//! Synthesis generation pipeline.
//!
//! Orchestrates the two-phase pipeline:
//! 1. Personalized sources: scrape user sources, classify+summarize per article
//! 2. Web search fallback: LLM search for missing categories, scrape to validate
//!
//! Progress is reported via `tokio::sync::watch` channels per job,
//! consumed by SSE endpoints for real-time client updates.

use std::collections::HashMap;
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::Arc;
use std::time::Duration;

use chrono::{DateTime, Utc};
use tokio::sync::watch;
use uuid::Uuid;

use crate::app_state::AppState;
use crate::db;
use crate::errors::AppError;
use crate::models::settings::UserSettings;
use crate::models::synthesis::{
    get_iso_week_string, NewsItem, NewsSection,
};
use crate::services::encryption;
use crate::services::llm::factory::create_provider;
use crate::services::scraper;
use crate::services::source_scraper;
use crate::services::feed_parser;

mod helpers;
pub(crate) use helpers::{
    ArticleTrace, assign_category, build_trace_entry, extract_domain,
    filter_phase2_url, hash_article_url,
};

// Re-export for downstream consumers that previously imported from synthesis.
pub use crate::services::job_store::{emit_progress, JobStore, ProgressEvent};

// ───────────────────────────────────────────────────────────────────
// Generation Pipeline
// ───────────────────────────────────────────────────────────────────

/// Run the full generation pipeline for a user.
///
/// This is the core orchestration function. It is spawned as a background
/// tokio task and communicates progress via the `watch` channel.
///
/// # Phases
/// 1. Personalized sources: extract links, scrape, classify+summarize per article
/// 2. Web search fallback: LLM search for under-filled categories, scrape to validate
/// 3. Save synthesis to DB
pub async fn run_generation(
    job_id: Uuid,
    state: AppState,
    user_id: Uuid,
    theme_id: Uuid,
    tx: Arc<watch::Sender<ProgressEvent>>,
    provider_override: Option<Arc<dyn crate::services::llm::LlmProvider>>,
    cancelled: Arc<AtomicBool>,
) {
    let result = run_generation_inner(job_id, &state, user_id, theme_id, &tx, provider_override, &cancelled).await;

    match result {
        Ok(synthesis_id) => {
            tx.send(ProgressEvent::Complete { synthesis_id }).ok();
            tracing::info!(job_id = %job_id, synthesis_id = %synthesis_id, "Generation completed");
        }
        Err(e) => {
            tracing::error!(job_id = %job_id, error = %e, "Generation failed");
            // Sanitize error message — never expose API keys or internal details
            let safe_message = sanitize_error_message(&e.to_string());
            tx.send(ProgressEvent::Error {
                message: safe_message,
            })
            .ok();
        }
    }

    // Keep the job in the store for 5 minutes after completion
    // to allow SSE reconnection
    let store = state.job_store.clone();
    let jid = job_id;
    tokio::spawn(async move {
        tokio::time::sleep(Duration::from_secs(300)).await;
        store.remove(&jid);
    });
}

/// Inner implementation of the generation pipeline, returning a Result.
pub async fn run_generation_inner(
    job_id: Uuid,
    state: &AppState,
    user_id: Uuid,
    theme_id: Uuid,
    tx: &watch::Sender<ProgressEvent>,
    provider_override: Option<Arc<dyn crate::services::llm::LlmProvider>>,
    cancelled: &AtomicBool,
) -> Result<Uuid, AppError> {
    // Batch buffer for article history traces (flushed at logical boundaries)
    let mut pending_traces: Vec<db::article_history::ArticleHistoryEntry> = Vec::new();

    // === INITIALIZATION ===
    emit_progress(tx, "sources", "Chargement des parametres...", 5);
    let settings = db::settings::get_or_create_default(&state.pool, user_id).await?;

    // Load theme
    let theme = db::themes::get_by_id(&state.pool, user_id, theme_id).await?
        .ok_or_else(|| AppError::BadRequest("Theme introuvable.".into()))?;
    let theme_categories: Vec<String> = serde_json::from_value(theme.categories).unwrap_or_default();

    if settings.article_history_days > 0 {
        db::article_history::cleanup_old(&state.pool, user_id, settings.article_history_days).await.unwrap_or(0);
        db::llm_call_log::truncate_old(&state.pool, user_id, settings.article_history_days).await.ok();
    }

    let user_categories = if theme_categories.is_empty() {
        Vec::new()
    } else {
        theme_categories.clone()
    };
    let mut classification_categories = user_categories.clone();
    classification_categories.push("Divers".to_string());

    emit_progress(tx, "sources", "Chargement des sources...", 10);
    let sources = db::sources::list_for_user(&state.pool, user_id, Some(theme_id)).await?;

    emit_progress(tx, "sources", "Configuration du fournisseur IA...", 12);
    let (provider_name, provider) = if let Some(mock_provider) = provider_override {
        ("mock".to_string(), mock_provider)
    } else {
        let (pname, api_key) = resolve_provider_and_key(state, user_id, &settings).await?;
        let p = create_provider(&pname, api_key)?;
        (pname, p)
    };
    let (model_research, model_websearch) = if provider_name == "mock" {
        let research = if settings.ai_model.is_empty() { "mock-model".to_string() } else { settings.ai_model.clone() };
        let websearch = if settings.ai_model_websearch.is_empty() { "mock-model".to_string() } else { settings.ai_model_websearch.clone() };
        (research, websearch)
    } else {
        let model_research = if !settings.ai_model.is_empty() { settings.ai_model.clone() } else { resolve_model(state, &provider_name).await? };
        let model_websearch = if !settings.ai_model_websearch.is_empty() { settings.ai_model_websearch.clone() } else { model_research.clone() };
        (model_research, model_websearch)
    };
    let user_rate_limiter = get_user_rate_limiter(state, &settings, user_id);

    // Tracking structures
    let mut article_scraped: HashMap<String, Vec<NewsItem>> = HashMap::new();
    let mut source_counts: HashMap<String, usize> = HashMap::new();
    let mut url_source: HashMap<String, String> = HashMap::new();
    let mut filled_counts: HashMap<String, usize> = HashMap::new();
    let mut seen_urls: std::collections::HashSet<String> = std::collections::HashSet::new();
    let max_total = (user_categories.len() + 1) * theme.max_items_per_category as usize;
    let classify_schema = Arc::new(crate::services::llm::schema::build_article_classify_schema());
    let model_research = Arc::new(model_research);
    let classification_categories = Arc::new(classification_categories);

    // === PHASE 1: Personalized Sources ===
    if !sources.is_empty() {
        emit_progress(tx, "sources", "Analyse des sources personnalisees...", 15);

        let last_source = db::article_history::get_last_source_url(&state.pool, user_id).await.unwrap_or(None);
        let rotated_sources = rotate_sources(sources.clone(), last_source.as_deref());
        // Preferred sources first, preserving rotation order within each group
        let preferred: Vec<_> = rotated_sources.iter().filter(|s| s.is_preferred).cloned().collect();
        let non_preferred: Vec<_> = rotated_sources.iter().filter(|s| !s.is_preferred).cloned().collect();
        let ordered_sources = [preferred, non_preferred].concat();
        let max_links = settings.max_links_per_source.max(1) as usize;
        let window_size = settings.source_extraction_window.max(1) as usize;

        // Process sources in waves of `window_size`
        let source_chunks: Vec<Vec<&crate::models::source::Source>> = ordered_sources
            .chunks(window_size)
            .map(|chunk| chunk.iter().collect())
            .collect();
        let total_waves = source_chunks.len();

        'wave_loop: for (wave_idx, wave_sources) in source_chunks.iter().enumerate() {
            // Check cancellation before each wave
            if cancelled.load(Ordering::Relaxed) {
                tracing::info!(job_id = %job_id, "Generation cancelled by user (before wave)");
                emit_progress(tx, "saving", "Generation arretee, sauvegarde...", 90);
                break 'wave_loop;
            }

            let articles_so_far: usize = article_scraped.values().map(|v| v.len()).sum();
            let pct = 5 + ((articles_so_far as u32 * 60) / max_total.max(1) as u32).min(60);
            emit_progress(tx, "sources",
                &format!("Vague {}/{} : extraction des sources...", wave_idx + 1, total_waves),
                pct as u8);

            // 1a. Extract links from this wave's sources (RSS-first with HTML fallback)
            let mut wave_urls: Vec<(String, String)> = Vec::new();
            let mut rss_updates: Vec<(Uuid, Option<String>, Option<DateTime<Utc>>)> = Vec::new();
            {
                let mut join_set = tokio::task::JoinSet::new();
                for source in wave_sources {
                    let client = state.http_client.clone();
                    let source_id = source.id;
                    let source_url = source.url.clone();
                    let source_title = source.title.clone();
                    let rss_url = source.rss_url.clone();
                    let rss_discovered_at = source.rss_discovered_at;
                    let max_l = max_links;
                    join_set.spawn(async move {
                        // Try RSS feed first
                        let feed_result = feed_parser::detect_and_parse_feed(
                            &client,
                            &source_url,
                            rss_url.as_deref(),
                            rss_discovered_at,
                            max_l,
                        ).await;

                        match feed_result {
                            feed_parser::FeedResult::Found { feed_url, entries }
                                if entries.len() >= feed_parser::MIN_FEED_ENTRIES =>
                            {
                                let links: Vec<String> = entries.into_iter().map(|e| e.url).collect();
                                tracing::info!(
                                    source = %source_title,
                                    feed = %feed_url,
                                    links = links.len(),
                                    "Extracted links from RSS feed"
                                );
                                // Signal RSS URL update if it changed
                                let rss_changed = rss_url.as_deref() != Some(&feed_url);
                                let rss_stale = rss_discovered_at
                                    .map(|d| Utc::now().signed_duration_since(d).num_days() >= feed_parser::REDISCOVERY_DAYS)
                                    .unwrap_or(true);
                                let update = if rss_changed || rss_stale {
                                    Some((source_id, Some(feed_url), Some(Utc::now())))
                                } else {
                                    None
                                };
                                (source_url, source_title, Ok(links), update)
                            }
                            feed_parser::FeedResult::Found { .. } => {
                                // Feed found but too few entries — keep the cache, fall back to HTML
                                let links = source_scraper::extract_article_links(&client, &source_url, max_l).await;
                                (source_url, source_title, links, None)
                            }
                            feed_parser::FeedResult::NotFound => {
                                // No feed discovered — fall back to HTML and clear any stale cache
                                let links = source_scraper::extract_article_links(&client, &source_url, max_l).await;
                                let update = if rss_url.is_some() {
                                    Some((source_id, None, None))
                                } else {
                                    None
                                };
                                (source_url, source_title, links, update)
                            }
                        }
                    });
                }

                while let Some(join_result) = join_set.join_next().await {
                    if let Ok((source_url, source_title, links_result, rss_update)) = join_result {
                        if let Some(update) = rss_update {
                            rss_updates.push(update);
                        }
                        match links_result {
                            Ok(links) => {
                                tracing::info!(source = %source_title, links = links.len(), "Extracted links from source");
                                for link in links {
                                    if seen_urls.insert(link.to_lowercase()) {
                                        wave_urls.push((link, source_url.clone()));
                                    }
                                }
                            }
                            Err(e) => {
                                tracing::warn!(source = %source_title, error = %e, "Failed to extract links");
                            }
                        }
                    }
                }
            }

            // Persist RSS URL updates (fire-and-forget)
            for (source_id, new_rss_url, new_discovered_at) in rss_updates {
                db::sources::update_source_rss(
                    &state.pool,
                    source_id,
                    user_id,
                    new_rss_url.as_deref(),
                    new_discovered_at,
                ).await.ok();
            }

            // 1b. Filter against article history
            if settings.article_history_days > 0 && !wave_urls.is_empty() {
                let hashes: Vec<String> = wave_urls.iter().map(|(url, _)| hash_article_url(url)).collect();
                let existing = db::article_history::check_urls_exist(&state.pool, user_id, &hashes).await.unwrap_or_default();
                if !existing.is_empty() {
                    for (url, source_url) in &wave_urls {
                        if existing.contains(&hash_article_url(url)) {
                            pending_traces.push(build_trace_entry(user_id, job_id, &ArticleTrace {
                                url, title: "", source_type: "personalized_source",
                                source_url: Some(source_url), category: None, synthesis_id: None,
                                status: "filtered_history", scraped_ok: false,
                                published_date: None,
                            }));
                        }
                    }
                    wave_urls.retain(|(url, _)| !existing.contains(&hash_article_url(url)));
                    // Flush history dedup traces
                    if !pending_traces.is_empty() {
                        db::article_history::batch_insert_entries(&state.pool, &pending_traces).await.ok();
                        pending_traces.clear();
                    }
                }
            }

            // 1c. Preferred-first shuffle: preferred source URLs first, then others
            use rand::seq::SliceRandom;
            {
                let preferred_source_urls: std::collections::HashSet<String> = wave_sources.iter()
                    .filter(|s| s.is_preferred)
                    .map(|s| s.url.clone())
                    .collect();

                let mut preferred_urls: Vec<_> = wave_urls.iter()
                    .filter(|(_, source_url)| preferred_source_urls.contains(source_url))
                    .cloned()
                    .collect();
                let mut other_urls: Vec<_> = wave_urls.iter()
                    .filter(|(_, source_url)| !preferred_source_urls.contains(source_url))
                    .cloned()
                    .collect();

                preferred_urls.shuffle(&mut rand::thread_rng());
                other_urls.shuffle(&mut rand::thread_rng());

                wave_urls = [preferred_urls, other_urls].concat();
            }

            // Track url -> source
            for (url, source_url) in &wave_urls {
                url_source.insert(url.clone(), source_url.clone());
            }

            // 1d. Batch scrape+classify (operates on this wave's URLs)
            if !wave_urls.is_empty() {
                let total_candidates = wave_urls.len();
                let batch_size = settings.batch_size.max(1) as usize;
                let snippet_size = match theme.summary_length { 1 => 500, 2 => 2000, _ => 4000 };
                let mut processed = 0usize;
                let mut candidates_iter = wave_urls.into_iter();
                let mut done = false;

                let ctx = ScrapeClassifyCtx {
                    state, user_id, job_id, provider: &provider,
                    model_research: &model_research, classify_schema: &classify_schema,
                    classification_categories: &classification_categories,
                    user_categories: &user_categories, snippet_size, summary_length: theme.summary_length,
                    max_age_days: theme.max_age_days as i64,
                    max_items_per_category: theme.max_items_per_category as usize,
                    source_type: "personalized_source",
                };

                while !done {
                    // Take next batch of candidates, filtering source limits
                    let mut batch: Vec<(String, Option<String>)> = Vec::new();
                    while batch.len() < batch_size {
                        let Some((url, source_url)) = candidates_iter.next() else {
                            break;
                        };
                        let source_domain = extract_domain(&source_url).unwrap_or_default();
                        let source_count = source_counts.get(&source_domain).copied().unwrap_or(0);
                        if source_count >= settings.max_articles_per_source as usize {
                            pending_traces.push(build_trace_entry(user_id, job_id, &ArticleTrace {
                                url: &url, title: "", source_type: "personalized_source",
                                source_url: Some(&source_url), category: None, synthesis_id: None,
                                status: "filtered_diversity", scraped_ok: false,
                                published_date: None,
                            }));
                            continue;
                        }
                        batch.push((url, Some(source_url)));
                    }

                    if batch.is_empty() {
                        break;
                    }

                    let articles_so_far: usize = article_scraped.values().map(|v| v.len()).sum();
                    let pct = 5 + ((articles_so_far as u32 * 60) / max_total.max(1) as u32).min(60);
                    emit_progress(tx, "sources", &format!("Vague {}/{} : articles {}/{}...", wave_idx + 1, total_waves, processed + 1, total_candidates), pct as u8);

                    scrape_and_classify_batch(
                        &ctx, &batch, &mut article_scraped, &mut filled_counts,
                        &mut source_counts, &mut pending_traces, &user_rate_limiter, &provider_name,
                    ).await?;

                    processed += batch.len();

                    // Check cancellation after each batch
                    if cancelled.load(Ordering::Relaxed) {
                        tracing::info!(job_id = %job_id, "Generation cancelled by user (after batch)");
                        emit_progress(tx, "saving", "Generation arretee, sauvegarde...", 90);
                        break;
                    }

                    // Check if we've reached the maximum after this batch
                    let total: usize = article_scraped.values().map(|v| v.len()).sum();
                    if total >= max_total {
                        done = true;
                    }
                }
            }

            // 1e. Check if full after this wave
            let total: usize = article_scraped.values().map(|v| v.len()).sum();
            if total >= max_total {
                tracing::info!(wave = wave_idx + 1, total_waves = total_waves, "Synthesis full after wave, skipping remaining sources");
                break 'wave_loop;
            }

            // 1f. Flush traces between waves
            if !pending_traces.is_empty() {
                db::article_history::batch_insert_entries(&state.pool, &pending_traces).await.ok();
                pending_traces.clear();
            }
        }
    }

    // === PHASE 2: Web Search Fallback ===
    // Skip Phase 2 if cancelled
    let is_cancelled = cancelled.load(Ordering::Relaxed);
    if is_cancelled {
        tracing::info!(job_id = %job_id, "Skipping Phase 2 — generation cancelled by user");
    }

    let category_gaps: Vec<(String, i32)> = user_categories.iter().filter_map(|cat| {
        let filled = filled_counts.get(cat).copied().unwrap_or(0);
        let needed = (theme.max_items_per_category as usize).saturating_sub(filled);
        if needed > 0 { Some((cat.clone(), needed as i32)) } else { None }
    }).collect();

    if !category_gaps.is_empty() && !is_cancelled {
        if settings.use_brave_search {
            // === BRAVE SEARCH PATH ===
            emit_progress(tx, "websearch", "Recherche Brave Search...", 70);

            let brave_key = resolve_brave_key(state, user_id).await?;
            let query = format!("{} actualites", theme.theme);
            let brave_results = crate::services::brave_search::search(
                &state.http_client, &brave_key, &query, 20, theme.max_age_days,
            ).await?;

            tracing::info!(results = brave_results.len(), "Brave Search returned results");

            // Filter Brave results
            let mut brave_urls: Vec<String> = Vec::new();
            for result in &brave_results {
                if let Some(reason) = filter_phase2_url(
                    &state.pool, user_id, &result.url, &seen_urls, &source_counts,
                    settings.article_history_days, settings.max_articles_per_source as usize,
                ).await {
                    pending_traces.push(build_trace_entry(user_id, job_id, &ArticleTrace {
                        url: &result.url, title: &result.title, source_type: "brave_search",
                        source_url: None, category: None, synthesis_id: None,
                        status: reason, scraped_ok: false,
                        published_date: None,
                    }));
                    continue;
                }

                seen_urls.insert(result.url.to_lowercase());
                url_source.insert(result.url.clone(), "brave_search".to_string());
                brave_urls.push(result.url.clone());
            }

            // Flush Brave filter traces
            if !pending_traces.is_empty() {
                db::article_history::batch_insert_entries(&state.pool, &pending_traces).await.ok();
                pending_traces.clear();
            }

            // Scrape + classify in batches (same as Phase 1)
            if !brave_urls.is_empty() {
                emit_progress(tx, "websearch", "Traitement des articles Brave...", 75);
                let total_candidates = brave_urls.len();
                let batch_size = settings.batch_size.max(1) as usize;
                let snippet_size = match theme.summary_length { 1 => 500, 2 => 2000, _ => 4000 };
                let mut processed = 0usize;
                let mut candidates_iter = brave_urls.into_iter();
                let mut done = false;

                let ctx = ScrapeClassifyCtx {
                    state, user_id, job_id, provider: &provider,
                    model_research: &model_research, classify_schema: &classify_schema,
                    classification_categories: &classification_categories,
                    user_categories: &user_categories, snippet_size, summary_length: theme.summary_length,
                    max_age_days: theme.max_age_days as i64,
                    max_items_per_category: theme.max_items_per_category as usize,
                    source_type: "brave_search",
                };

                while !done {
                    let mut batch: Vec<(String, Option<String>)> = Vec::new();
                    while batch.len() < batch_size {
                        let Some(url) = candidates_iter.next() else { break };
                        batch.push((url, None));
                    }

                    if batch.is_empty() { break; }

                    let pct = 75 + ((processed as u32 * 10) / total_candidates.max(1) as u32).min(10);
                    emit_progress(tx, "websearch", &format!("Verification des sources {}/{}...", processed + 1, total_candidates), pct as u8);

                    scrape_and_classify_batch(
                        &ctx, &batch, &mut article_scraped, &mut filled_counts,
                        &mut source_counts, &mut pending_traces, &user_rate_limiter, &provider_name,
                    ).await?;

                    processed += batch.len();

                    let total: usize = article_scraped.values().map(|v| v.len()).sum();
                    if total >= max_total {
                        done = true;
                    }
                }

                // Flush Brave scrape/classify traces
                if !pending_traces.is_empty() {
                    db::article_history::batch_insert_entries(&state.pool, &pending_traces).await.ok();
                    pending_traces.clear();
                }
            }
        } else {
            // === EXISTING LLM SEARCH PATH ===
            emit_progress(tx, "websearch", "Recherche d'actualites...", 70);
            check_rate_limit(state, &user_rate_limiter, &provider_name).await?;

            let search_schema = crate::services::llm::schema::build_category_schema(&user_categories, theme.max_items_per_category);
            let current_date = Utc::now().format("%A %d %B %Y").to_string();
            let (sys_prompt, usr_prompt) = crate::services::prompts::build_search_prompt(&theme.theme, &user_categories, theme.max_items_per_category, theme.max_age_days, &settings.search_agent_behavior, &[], &current_date, &[], Some(&category_gaps));

            let llm_start = std::time::Instant::now();
            let raw_results = provider.call_llm(&model_websearch, &sys_prompt, &usr_prompt, &search_schema).await?;
            let llm_duration = llm_start.elapsed().as_millis() as u64;
            log_llm_call(&state.pool, user_id, job_id, "search", &model_websearch, &sys_prompt, &usr_prompt, &raw_results, llm_duration, None).await;

            emit_progress(tx, "websearch", "Analyse des resultats...", 75);
            let parsed = parse_llm_output(&raw_results, &user_categories)?;

            // Filter and validate Phase 2 articles
            let mut phase2_items: Vec<(String, NewsItem)> = Vec::new();

            for (cat_key, items) in parsed {
                for item in items {
                    if let Some(reason) = filter_phase2_url(
                        &state.pool, user_id, &item.url, &seen_urls, &source_counts,
                        settings.article_history_days, settings.max_articles_per_source as usize,
                    ).await {
                        pending_traces.push(build_trace_entry(user_id, job_id, &ArticleTrace {
                            url: &item.url, title: &item.title, source_type: "web_search",
                            source_url: None, category: None, synthesis_id: None,
                            status: reason, scraped_ok: false,
                            published_date: None,
                        }));
                        continue;
                    }

                    seen_urls.insert(item.url.to_lowercase());
                    phase2_items.push((cat_key.clone(), item));
                }
            }

            // Flush Phase 2 filter traces
            if !pending_traces.is_empty() {
                db::article_history::batch_insert_entries(&state.pool, &pending_traces).await.ok();
                pending_traces.clear();
            }

            // Scrape Phase 2 for validation
            emit_progress(tx, "websearch", "Verification des sources...", 80);
            for (cat_key, item) in phase2_items {
                let (_body_text, _, final_url, drop_reason) = scrape_single_article(&state.http_client, &item.url, theme.max_age_days as i64).await;

                if let Some(reason) = drop_reason {
                    pending_traces.push(build_trace_entry(user_id, job_id, &ArticleTrace {
                        url: &final_url, title: &item.title, source_type: "web_search",
                        source_url: None, category: None, synthesis_id: None,
                        status: reason, scraped_ok: false,
                        published_date: None,
                    }));
                    continue;
                }

                article_scraped.entry(cat_key).or_default().push(NewsItem {
                    title: item.title,
                    url: final_url,
                    summary: item.summary,
                    date: None,
                });

                if let Some(domain) = extract_domain(&item.url) {
                    *source_counts.entry(domain).or_insert(0) += 1;
                }
            }

            // Flush Phase 2 scrape traces
            if !pending_traces.is_empty() {
                db::article_history::batch_insert_entries(&state.pool, &pending_traces).await.ok();
                pending_traces.clear();
            }
        }
    }

    // === SAVE ===
    let is_cancelled = cancelled.load(Ordering::Relaxed);
    let has_articles = article_scraped.values().any(|items| !items.is_empty());

    if !has_articles {
        if is_cancelled {
            return Err(AppError::BadRequest("Generation arretee. Aucun article n'avait encore ete collecte.".into()));
        }
        return Err(AppError::BadRequest("Aucun article valide trouve. Verifiez vos sources et categories.".into()));
    }

    if is_cancelled {
        emit_progress(tx, "saving", "Generation arretee, sauvegarde des articles collectes...", 90);
    } else {
        emit_progress(tx, "saving", "Sauvegarde de la synthese...", 90);
    }

    let mut final_sections: Vec<NewsSection> = Vec::new();
    for (i, cat_name) in user_categories.iter().enumerate() {
        let key = format!("category_{}", i);
        if let Some(items) = article_scraped.get(&key) {
            if !items.is_empty() {
                final_sections.push(NewsSection { title: cat_name.clone(), items: items.clone() });
            }
        }
    }
    if let Some(autre_items) = article_scraped.get("category_autre") {
        if !autre_items.is_empty() {
            final_sections.push(NewsSection { title: "Divers".to_string(), items: autre_items.clone() });
        }
    }

    let sections_json = serde_json::to_value(&final_sections).map_err(|e| AppError::Internal(anyhow::anyhow!("Failed to serialize: {}", e)))?;
    let sections_json = sanitize_json_null_bytes(sections_json);

    let synthesis = db::syntheses::create(&state.pool, user_id, &get_iso_week_string(Utc::now().date_naive()), &sections_json, job_id, Some(theme_id)).await?;

    if settings.article_history_days > 0 {
        for section in &final_sections {
            for item in &section.items {
                let source_type = match url_source.get(&item.url).map(|s| s.as_str()) {
                    Some("brave_search") => "brave_search",
                    Some(_) => "personalized_source",
                    None => "web_search",
                };
                pending_traces.push(build_trace_entry(user_id, job_id, &ArticleTrace {
                    url: &item.url, title: &item.title, source_type,
                    source_url: if source_type == "personalized_source" { url_source.get(&item.url).map(|s| s.as_str()) } else { None },
                    category: Some(&section.title), synthesis_id: Some(synthesis.id),
                    status: "used", scraped_ok: true,
                    published_date: item.date.as_deref(),
                }));
            }
        }

        // Flush final "used" traces
        if !pending_traces.is_empty() {
            db::article_history::batch_insert_entries(&state.pool, &pending_traces).await.ok();
            pending_traces.clear();
        }
    }

    Ok(synthesis.id)
}

// ───────────────────────────────────────────────────────────────────
// Helper Functions
// ───────────────────────────────────────────────────────────────────

/// Recursively strip `\u0000` null bytes from JSON values.
///
/// PostgreSQL rejects null bytes in JSONB text. LLM output occasionally
/// contains them (e.g., `Meta AI a annonc\u0000...`).
fn sanitize_json_null_bytes(value: serde_json::Value) -> serde_json::Value {
    match value {
        serde_json::Value::String(s) => serde_json::Value::String(s.replace('\0', "")),
        serde_json::Value::Array(arr) => {
            serde_json::Value::Array(arr.into_iter().map(sanitize_json_null_bytes).collect())
        }
        serde_json::Value::Object(map) => serde_json::Value::Object(
            map.into_iter()
                .map(|(k, v)| (k, sanitize_json_null_bytes(v)))
                .collect(),
        ),
        other => other,
    }
}

/// Context passed to [`scrape_and_classify_batch`] to avoid long argument lists.
struct ScrapeClassifyCtx<'a> {
    state: &'a AppState,
    user_id: Uuid,
    job_id: Uuid,
    provider: &'a Arc<dyn crate::services::llm::LlmProvider>,
    model_research: &'a Arc<String>,
    classify_schema: &'a Arc<serde_json::Value>,
    classification_categories: &'a Arc<Vec<String>>,
    user_categories: &'a [String],
    snippet_size: usize,
    summary_length: i32,
    max_age_days: i64,
    max_items_per_category: usize,
    source_type: &'a str,
}

/// Scrape and classify a batch of articles, updating shared state.
///
/// Each article is represented as `(url, Option<source_url>)`.
/// - `source_type` is used for tracing (e.g. "personalized_source", "brave_search").
/// - When `source_url` is `Some`, it is recorded in traces; the domain for
///   source counting comes from the source URL.
/// - When `source_url` is `None`, traces have no source URL; the domain for
///   source counting comes from the article URL.
#[allow(clippy::too_many_arguments)]
async fn scrape_and_classify_batch(
    ctx: &ScrapeClassifyCtx<'_>,
    articles: &[(String, Option<String>)],
    article_scraped: &mut HashMap<String, Vec<NewsItem>>,
    filled_counts: &mut HashMap<String, usize>,
    source_counts: &mut HashMap<String, usize>,
    pending_traces: &mut Vec<db::article_history::ArticleHistoryEntry>,
    user_rate_limiter: &Option<crate::services::rate_limiter::RateLimiter>,
    provider_name: &str,
) -> Result<(), AppError> {
    // Phase A: Scrape batch in parallel
    let mut scrape_set = tokio::task::JoinSet::new();
    for (url, source_url) in articles {
        let client = ctx.state.http_client.clone();
        let u = url.clone();
        let su = source_url.clone();
        let mad = ctx.max_age_days;
        scrape_set.spawn(async move {
            let result = scrape_single_article(&client, &u, mad).await;
            (u, su, result)
        });
    }

    let mut scraped_articles: Vec<(String, Option<String>, String, String)> = Vec::new();
    while let Some(join_result) = scrape_set.join_next().await {
        if let Ok((_url, source_url, (body_text, page_title, final_url, drop_reason))) = join_result {
            if let Some(reason) = drop_reason {
                pending_traces.push(build_trace_entry(ctx.user_id, ctx.job_id, &ArticleTrace {
                    url: &final_url, title: &page_title, source_type: ctx.source_type,
                    source_url: source_url.as_deref(), category: None, synthesis_id: None,
                    status: reason, scraped_ok: false,
                    published_date: None,
                }));
            } else {
                scraped_articles.push((final_url, source_url, body_text, page_title));
            }
        }
    }

    if scraped_articles.is_empty() {
        return Ok(());
    }

    // Phase B: Classify/summarize batch in parallel
    check_rate_limit(ctx.state, user_rate_limiter, provider_name).await?;

    let mut classify_set = tokio::task::JoinSet::new();
    for (final_url, source_url, body_text, page_title) in &scraped_articles {
        let provider_clone = Arc::clone(ctx.provider);
        let model = Arc::clone(ctx.model_research);
        let schema = Arc::clone(ctx.classify_schema);
        let cats = Arc::clone(ctx.classification_categories);
        let body_snippet: String = body_text.chars().take(ctx.snippet_size).collect();
        let title = page_title.clone();
        let url = final_url.clone();
        let su = source_url.clone();
        let pool = ctx.state.pool.clone();
        let uid = ctx.user_id;
        let jid = ctx.job_id;
        let summary_length = ctx.summary_length;

        let (sys, usr) = crate::services::prompts::build_article_classify_prompt(&title, &body_snippet, &cats, summary_length);

        classify_set.spawn(async move {
            let llm_start = std::time::Instant::now();
            let result = provider_clone.call_llm(&model, &sys, &usr, &schema).await;
            let duration = llm_start.elapsed().as_millis() as u64;

            if let Ok(ref resp) = result {
                let resp_str = serde_json::to_string_pretty(resp).unwrap_or_default();
                crate::db::llm_call_log::insert(&pool, uid, jid, "classify_summarize", &model, &sys, &usr, &resp_str, duration as i32, Some(&url)).await.ok();
            }

            (url, su, title, result)
        });
    }

    while let Some(join_result) = classify_set.join_next().await {
        if let Ok((final_url, source_url, page_title, llm_result)) = join_result {
            let class_response = match llm_result {
                Ok(resp) => resp,
                Err(e) => {
                    tracing::warn!(url = %final_url, error = %e, "LLM classify failed, skipping article");
                    continue;
                }
            };

            // Check if LLM considers this a real article
            let is_article = class_response.get("is_article").and_then(|v| v.as_bool()).unwrap_or(true);
            if !is_article {
                tracing::info!(url = %final_url, "Article filtered by LLM: not a real article");
                pending_traces.push(build_trace_entry(ctx.user_id, ctx.job_id, &ArticleTrace {
                    url: &final_url, title: &page_title, source_type: ctx.source_type,
                    source_url: source_url.as_deref(), category: None, synthesis_id: None,
                    status: "filtered_not_article", scraped_ok: true,
                    published_date: None,
                }));
                continue;
            }

            // Check LLM-extracted date as fallback
            if let Some(date_str) = class_response.get("date").and_then(|d| d.as_str()) {
                if !date_str.is_empty() {
                    if let Some(parsed) = scraper::parse_date_string(date_str) {
                        if scraper::is_article_too_old(Some(parsed), ctx.max_age_days) {
                            tracing::info!(url = %final_url, date = date_str, "Article filtered by LLM-extracted date (too old)");
                            pending_traces.push(build_trace_entry(ctx.user_id, ctx.job_id, &ArticleTrace {
                                url: &final_url, title: &page_title, source_type: ctx.source_type,
                                source_url: source_url.as_deref(), category: None, synthesis_id: None,
                                status: "filtered_too_old", scraped_ok: true,
                                published_date: Some(date_str),
                            }));
                            continue;
                        }
                    }
                }
            }

            let llm_date = class_response.get("date").and_then(|d| d.as_str()).filter(|s| !s.is_empty()).map(|s| s.to_string());

            // Domain for source counting: prefer source_url if available, else article url
            let count_domain = source_url.as_deref()
                .and_then(extract_domain)
                .or_else(|| extract_domain(&final_url));

            let Some((final_cat_key, final_cat_name, llm_title, llm_summary)) = assign_category(
                &class_response, &page_title, ctx.user_categories, ctx.classification_categories,
                filled_counts, ctx.max_items_per_category,
            ) else {
                continue;
            };

            article_scraped.entry(final_cat_key).or_default().push(NewsItem {
                title: llm_title,
                url: final_url.clone(),
                summary: llm_summary,
                date: llm_date,
            });
            *filled_counts.entry(final_cat_name).or_insert(0) += 1;

            if let Some(domain) = count_domain {
                *source_counts.entry(domain).or_insert(0) += 1;
            }
        }
    }

    Ok(())
}

/// Log an LLM call with full prompt, response, and timing.
#[allow(clippy::too_many_arguments)]
async fn log_llm_call(
    pool: &sqlx::PgPool,
    user_id: Uuid,
    job_id: Uuid,
    call_type: &str,
    model: &str,
    system_prompt: &str,
    user_prompt: &str,
    response: &serde_json::Value,
    duration_ms: u64,
    article_url: Option<&str>,
) {
    let response_str = serde_json::to_string_pretty(response).unwrap_or_default();
    db::llm_call_log::insert(
        pool, user_id, job_id, call_type, model,
        system_prompt, user_prompt, &response_str, duration_ms as i32,
        article_url,
    )
    .await
    .ok(); // Don't fail synthesis if logging fails
}

/// Look up or create a per-user rate limiter stored in AppState.
///
/// Returns `None` if the user has no rate limit overrides, in which case the
/// global provider rate limiter should be used instead.
///
/// Uses DashMap's entry API for atomic check-and-insert, preventing concurrent
/// generation jobs from creating independent limiters for the same user.
fn get_user_rate_limiter(
    state: &AppState,
    settings: &UserSettings,
    user_id: Uuid,
) -> Option<crate::services::rate_limiter::RateLimiter> {
    use crate::app_state::UserRateLimitEntry;

    match (
        settings.rate_limit_max_requests,
        settings.rate_limit_time_window_seconds,
    ) {
        (Some(max_req), Some(window_sec)) => {
            let mut entry = state
                .user_rate_limiters
                .entry(user_id)
                .or_insert_with(|| UserRateLimitEntry::new(max_req, window_sec));
            // Replace if user's settings changed since the limiter was created
            if entry.settings_changed(max_req, window_sec) {
                *entry = UserRateLimitEntry::new(max_req, window_sec);
            }
            Some(entry.limiter.clone())
        }
        _ => {
            state.user_rate_limiters.remove(&user_id);
            None
        }
    }
}

/// Check rate limits using the user's limiter if provided, otherwise the global limiter.
/// Check rate limits, waiting if necessary (up to 60 seconds).
///
/// Instead of failing with an error, this function sleeps until the rate
/// limit window passes. If still rate limited after 60 seconds, returns an error.
async fn check_rate_limit(
    state: &AppState,
    user_limiter: &Option<crate::services::rate_limiter::RateLimiter>,
    provider_name: &str,
) -> Result<(), AppError> {
    let max_wait = std::time::Duration::from_secs(60);
    let start = std::time::Instant::now();

    loop {
        let allowed = match user_limiter {
            Some(limiter) => limiter.check(&format!("user_gen_{}", provider_name)),
            None => state.provider_rate_limiter.check(provider_name),
        };

        if allowed {
            return Ok(());
        }

        // Calculate how long to wait
        let wait_time = match user_limiter {
            Some(limiter) => limiter.time_until_available(&format!("user_gen_{}", provider_name)),
            None => state.provider_rate_limiter.time_until_available(provider_name),
        };

        let wait = wait_time.unwrap_or(std::time::Duration::from_secs(1));

        if start.elapsed() + wait > max_wait {
            return Err(AppError::RateLimited(
                "Limite de requetes atteinte. Veuillez reessayer dans quelques instants.".into(),
            ));
        }

        tracing::info!(wait_ms = wait.as_millis() as u64, "Rate limited, waiting...");
        tokio::time::sleep(wait).await;
    }
}

/// Decrypt the Brave Search API key for a user.
async fn resolve_brave_key(
    state: &AppState,
    user_id: Uuid,
) -> Result<String, AppError> {
    let master_key = encryption::MasterKey::from_hex(&state.config.master_encryption_key)?;
    let key_record = db::api_keys::get_for_user_and_provider(
        &state.pool, user_id, "brave_search",
    ).await?
    .ok_or_else(|| AppError::BadRequest(
        "Brave Search est active mais aucune cle API Brave n'est configuree. \
         Veuillez ajouter une cle API Brave Search dans vos parametres.".into(),
    ))?;

    encryption::decrypt(&master_key, &key_record.encrypted_key, &key_record.nonce)
}

/// Resolve the LLM provider and decrypt the user's API key.
///
/// If the user has a preferred provider in settings, looks for a key matching
/// that provider specifically. Otherwise falls back to the first available key.
async fn resolve_provider_and_key(
    state: &AppState,
    user_id: Uuid,
    settings: &UserSettings,
) -> Result<(String, String), AppError> {
    let master_key = encryption::MasterKey::from_hex(&state.config.master_encryption_key)?;

    // If the user has a preferred provider, look for that specific key
    if !settings.ai_provider.is_empty() {
        let key_record = db::api_keys::get_for_user_and_provider(
            &state.pool,
            user_id,
            &settings.ai_provider,
        )
        .await?;

        match key_record {
            Some(record) => {
                let api_key =
                    encryption::decrypt(&master_key, &record.encrypted_key, &record.nonce)?;
                return Ok((record.provider_name.clone(), api_key));
            }
            None => {
                return Err(AppError::BadRequest(format!(
                    "Aucune cle API configuree pour le fournisseur '{}'. \
                     Veuillez ajouter une cle API pour ce fournisseur dans vos parametres.",
                    settings.ai_provider
                )));
            }
        }
    }

    // Fall back to first available key
    let keys = db::api_keys::list_for_user(&state.pool, user_id).await?;

    if keys.is_empty() {
        return Err(AppError::BadRequest(
            "Aucune cle API configuree. Veuillez ajouter une cle API dans vos parametres.".into(),
        ));
    }

    let key_record = &keys[0];
    let api_key = encryption::decrypt(
        &master_key,
        &key_record.encrypted_key,
        &key_record.nonce,
    )?;

    Ok((key_record.provider_name.clone(), api_key))
}

/// Resolve the model to use for a given provider.
///
/// Looks up the first enabled model for the provider from the admin config.
/// Falls back to sensible defaults if no admin-configured models exist.
async fn resolve_model(state: &AppState, provider_name: &str) -> Result<String, AppError> {
    // Try to get the default model from the admin_providers JSONB models_scraping array
    let model = sqlx::query_scalar::<_, String>(
        r#"
        SELECT m->>'model_id'
        FROM admin_providers, jsonb_array_elements(models_scraping) AS m
        WHERE provider_name = $1 AND is_enabled = true AND (m->>'is_default')::boolean = true
        LIMIT 1
        "#,
    )
    .bind(provider_name)
    .fetch_optional(&state.pool)
    .await?;

    match model {
        Some(m) => Ok(m),
        None => {
            // Fall back to sensible defaults
            match provider_name {
                "gemini" => Ok("gemini-2.5-pro".into()),
                "openai" => Ok("gpt-4o".into()),
                "anthropic" => Ok("claude-sonnet-4-20250514".into()),
                _ => Err(AppError::BadRequest(format!(
                    "Aucun modele configure pour le fournisseur '{}'",
                    provider_name
                ))),
            }
        }
    }
}

/// Parse the LLM's structured JSON output into category-keyed news items.
///
/// Expects the output to have keys like `category_0`, `category_1`, etc.
/// Each key maps to an array of `{title, url, summary}` objects.
fn parse_llm_output(
    raw: &serde_json::Value,
    categories: &[String],
) -> Result<Vec<(String, Vec<NewsItem>)>, AppError> {
    let mut result = Vec::new();

    for (i, _cat) in categories.iter().enumerate() {
        let key = format!("category_{}", i);
        let items_val = raw.get(&key).cloned().unwrap_or(serde_json::json!([]));

        let items: Vec<NewsItem> = serde_json::from_value(items_val).unwrap_or_default();
        result.push((key, items));
    }

    Ok(result)
}

/// Rotate the sources list so that the source after the last-used source comes first.
fn rotate_sources(sources: Vec<crate::models::source::Source>, last_source_url: Option<&str>) -> Vec<crate::models::source::Source> {
    let Some(last_url) = last_source_url else {
        return sources;
    };
    let pos = sources.iter().position(|s| s.url == last_url);
    match pos {
        Some(idx) => {
            let next = (idx + 1) % sources.len();
            let mut rotated = sources[next..].to_vec();
            rotated.extend_from_slice(&sources[..next]);
            rotated
        }
        None => sources,
    }
}

/// Scrape a single article. Returns (body_text, page_title, final_url, drop_reason).
/// `drop_reason` is `Some("filtered_empty")` or `Some("filtered_too_old")` if rejected, `None` if OK.
async fn scrape_single_article(
    http_client: &reqwest::Client,
    url: &str,
    max_age_days: i64,
) -> (String, String, String, Option<&'static str>) {
    match scraper::scrape_url(http_client, url).await {
        Ok(content) => {
            let final_url = content.url.clone();
            if !content.ok || content.is_soft_404 {
                tracing::warn!(url = url, "Soft 404 or error page detected, skipping content");
                return (String::new(), String::new(), final_url, Some("filtered_empty"));
            }
            if scraper::is_article_too_old(content.published_date, max_age_days) {
                tracing::warn!(url = url, "Article too old, skipping content");
                return (String::new(), String::new(), final_url, Some("filtered_too_old"));
            }
            let title = content.title.unwrap_or_default();
            (content.body_text, title, final_url, None)
        }
        Err(e) => {
            tracing::warn!(url = url, error = %e, "Failed to scrape URL, keeping article with empty content");
            (String::new(), String::new(), url.to_string(), Some("filtered_empty"))
        }
    }
}

/// Sanitize error messages to prevent leaking sensitive information.
///
/// Removes potential API keys, internal paths, and other sensitive data.
fn sanitize_error_message(msg: &str) -> String {
    // If the message contains common API key patterns, replace with generic message
    if msg.contains("API key")
        || msg.contains("api_key")
        || msg.contains("AIza")
        || msg.contains("sk-")
        || msg.contains("sk-ant-")
        || msg.contains("PERMISSION_DENIED")
    {
        return "Erreur d'authentification avec le fournisseur IA. Verifiez votre cle API.".into();
    }

    if msg.contains("rate limit") || msg.contains("quota") || msg.contains("429") {
        return "Limite de requetes du fournisseur IA atteinte. Reessayez plus tard.".into();
    }

    if msg.contains("Database") || msg.contains("sqlx") || msg.contains("postgres") {
        return "Erreur interne du serveur. Veuillez reessayer.".into();
    }

    // For other errors, truncate and sanitize
    if msg.len() > 200 {
        let truncated: String = msg.chars().take(200).collect();
        format!("{}...", truncated)
    } else {
        msg.to_string()
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    // ── parse_llm_output tests ───────────────────────────────────

    #[test]
    fn parse_llm_output_valid() {
        let raw = serde_json::json!({
            "category_0": [
                {"title": "Art 1", "url": "https://a.com", "summary": "Sum 1"},
                {"title": "Art 2", "url": "https://b.com", "summary": "Sum 2"}
            ],
            "category_1": [
                {"title": "Art 3", "url": "https://c.com", "summary": "Sum 3"}
            ]
        });

        let categories = vec!["AI News".into(), "Research".into()];
        let result = parse_llm_output(&raw, &categories).unwrap();

        assert_eq!(result.len(), 2);
        assert_eq!(result[0].0, "category_0");
        assert_eq!(result[0].1.len(), 2);
        assert_eq!(result[1].0, "category_1");
        assert_eq!(result[1].1.len(), 1);
    }

    #[test]
    fn parse_llm_output_missing_category() {
        let raw = serde_json::json!({
            "category_0": [
                {"title": "Art 1", "url": "https://a.com", "summary": "Sum 1"}
            ]
            // category_1 is missing
        });

        let categories = vec!["AI News".into(), "Research".into()];
        let result = parse_llm_output(&raw, &categories).unwrap();

        assert_eq!(result.len(), 2);
        assert_eq!(result[0].1.len(), 1);
        assert_eq!(result[1].1.len(), 0); // Missing category → empty
    }

    // ── sanitize_error_message tests ─────────────────────────────

    #[test]
    fn sanitize_hides_api_key_references() {
        let msg = "Invalid API key: AIzaSyB-test-key";
        let sanitized = sanitize_error_message(msg);
        assert!(sanitized.contains("cle API"));
        assert!(!sanitized.contains("AIza"));
    }

    #[test]
    fn sanitize_hides_rate_limit_details() {
        let msg = "Resource exhausted: rate limit exceeded for project 12345";
        let sanitized = sanitize_error_message(msg);
        assert!(sanitized.contains("Limite"));
        assert!(!sanitized.contains("12345"));
    }

    #[test]
    fn sanitize_hides_database_details() {
        let msg = "Database connection to postgres://user:pass@localhost failed";
        let sanitized = sanitize_error_message(msg);
        assert!(sanitized.contains("Erreur interne"));
        assert!(!sanitized.contains("postgres"));
    }

    #[test]
    fn sanitize_truncates_long_messages() {
        let msg = "x".repeat(300);
        let sanitized = sanitize_error_message(&msg);
        assert!(sanitized.len() < 210);
        assert!(sanitized.ends_with("..."));
    }

    #[test]
    fn sanitize_passes_normal_messages() {
        let msg = "Generation failed due to network timeout";
        let sanitized = sanitize_error_message(msg);
        assert_eq!(sanitized, msg);
    }

    // ── sanitize_json_null_bytes tests ──────────────────────────

    #[test]
    fn sanitize_null_bytes_in_json_strings() {
        let json = serde_json::json!({
            "title": "Hello\u{0000}World",
            "items": [{"summary": "Text\u{0000}with\u{0000}nulls"}]
        });
        let sanitized = sanitize_json_null_bytes(json);
        assert_eq!(sanitized["title"], "HelloWorld");
        assert_eq!(sanitized["items"][0]["summary"], "Textwithnulls");
    }

    #[test]
    fn sanitize_preserves_clean_json() {
        let json = serde_json::json!({
            "title": "Clean text",
            "count": 42,
            "active": true,
            "items": [{"url": "https://example.com"}]
        });
        let sanitized = sanitize_json_null_bytes(json.clone());
        assert_eq!(sanitized, json);
    }

    // ── rotate_sources tests ──────────────────────────────────

    #[test]
    fn rotate_sources_no_last_url() {
        let sources = vec![
            crate::models::source::Source { id: Uuid::new_v4(), user_id: Uuid::new_v4(), title: "A".into(), url: "https://a.com".into(), theme_id: None, is_preferred: false, rss_url: None, rss_discovered_at: None, created_at: chrono::Utc::now() },
            crate::models::source::Source { id: Uuid::new_v4(), user_id: Uuid::new_v4(), title: "B".into(), url: "https://b.com".into(), theme_id: None, is_preferred: false, rss_url: None, rss_discovered_at: None, created_at: chrono::Utc::now() },
        ];
        let result = rotate_sources(sources.clone(), None);
        assert_eq!(result.len(), 2);
        assert_eq!(result[0].url, "https://a.com");
    }

    #[test]
    fn rotate_sources_with_last_url() {
        let sources = vec![
            crate::models::source::Source { id: Uuid::new_v4(), user_id: Uuid::new_v4(), title: "A".into(), url: "https://a.com".into(), theme_id: None, is_preferred: false, rss_url: None, rss_discovered_at: None, created_at: chrono::Utc::now() },
            crate::models::source::Source { id: Uuid::new_v4(), user_id: Uuid::new_v4(), title: "B".into(), url: "https://b.com".into(), theme_id: None, is_preferred: false, rss_url: None, rss_discovered_at: None, created_at: chrono::Utc::now() },
            crate::models::source::Source { id: Uuid::new_v4(), user_id: Uuid::new_v4(), title: "C".into(), url: "https://c.com".into(), theme_id: None, is_preferred: false, rss_url: None, rss_discovered_at: None, created_at: chrono::Utc::now() },
        ];
        let result = rotate_sources(sources, Some("https://a.com"));
        assert_eq!(result[0].url, "https://b.com");
        assert_eq!(result[1].url, "https://c.com");
        assert_eq!(result[2].url, "https://a.com");
    }

    #[test]
    fn rotate_sources_last_url_not_found() {
        let sources = vec![
            crate::models::source::Source { id: Uuid::new_v4(), user_id: Uuid::new_v4(), title: "A".into(), url: "https://a.com".into(), theme_id: None, is_preferred: false, rss_url: None, rss_discovered_at: None, created_at: chrono::Utc::now() },
        ];
        let result = rotate_sources(sources.clone(), Some("https://notfound.com"));
        assert_eq!(result[0].url, "https://a.com");
    }

    #[test]
    fn sanitize_error_message_handles_multibyte_utf8() {
        let msg = "é".repeat(150); // 300 bytes, 150 chars
        let result = sanitize_error_message(&msg);
        assert!(result.ends_with("..."));
    }

}