feat: article history entry struct + insert/query/cleanup functions

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/db/article_history.rs

@@ -3,10 +3,43 @@
 //! Prevents the same article from appearing in multiple syntheses.
 
 use std::collections::HashSet;
+use chrono::{DateTime, Utc};
+use serde::Serialize;
 use sqlx::PgPool;
 use uuid::Uuid;
 use crate::errors::AppError;
 
+/// Entry for inserting into article_history with full tracing metadata.
+pub struct ArticleHistoryEntry {
+    pub user_id: Uuid,
+    pub url: String,
+    pub url_hash: String,
+    pub title: String,
+    pub source_type: String,
+    pub source_url: Option<String>,
+    pub category: Option<String>,
+    pub synthesis_id: Option<Uuid>,
+    pub status: String,
+    pub scraped_ok: bool,
+    pub job_id: Uuid,
+}
+
+/// Row returned from article_history queries.
+#[derive(Debug, Clone, Serialize, sqlx::FromRow)]
+pub struct ArticleHistoryRow {
+    pub id: Uuid,
+    pub url: String,
+    pub title: String,
+    pub source_type: String,
+    pub source_url: Option<String>,
+    pub category: Option<String>,
+    pub synthesis_id: Option<Uuid>,
+    pub status: String,
+    pub scraped_ok: bool,
+    pub job_id: Uuid,
+    pub created_at: DateTime<Utc>,
+}
+
 /// Check which URL hashes already exist in history for this user.
 ///
 /// Returns the set of url_hashes that were found (i.e., already used).
@@ -56,8 +89,109 @@ pub async fn insert_urls(
     Ok(())
 }
 
+/// Insert a single article history entry with full tracing metadata.
+pub async fn insert_entry(pool: &PgPool, entry: &ArticleHistoryEntry) -> Result<(), AppError> {
+    sqlx::query(
+        r#"
+        INSERT INTO article_history (user_id, url_hash, url, title, source_type, source_url, category, synthesis_id, status, scraped_ok, job_id)
+        VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11)
+        "#,
+    )
+    .bind(entry.user_id)
+    .bind(&entry.url_hash)
+    .bind(&entry.url)
+    .bind(&entry.title)
+    .bind(&entry.source_type)
+    .bind(&entry.source_url)
+    .bind(&entry.category)
+    .bind(entry.synthesis_id)
+    .bind(&entry.status)
+    .bind(entry.scraped_ok)
+    .bind(entry.job_id)
+    .execute(pool)
+    .await?;
+    Ok(())
+}
+
+/// List article history with optional filters, paginated.
+pub async fn list_history(
+    pool: &PgPool,
+    user_id: Uuid,
+    limit: i64,
+    offset: i64,
+    status_filter: Option<&str>,
+    source_type_filter: Option<&str>,
+) -> Result<Vec<ArticleHistoryRow>, AppError> {
+    let rows = sqlx::query_as::<_, ArticleHistoryRow>(
+        r#"
+        SELECT id, url, title, source_type, source_url, category, synthesis_id, status, scraped_ok, job_id, created_at
+        FROM article_history
+        WHERE user_id = $1
+            AND ($4::TEXT IS NULL OR status = $4)
+            AND ($5::TEXT IS NULL OR source_type = $5)
+        ORDER BY created_at DESC
+        LIMIT $2 OFFSET $3
+        "#,
+    )
+    .bind(user_id)
+    .bind(limit)
+    .bind(offset)
+    .bind(status_filter)
+    .bind(source_type_filter)
+    .fetch_all(pool)
+    .await?;
+    Ok(rows)
+}
+
+/// Count article history entries with optional filters.
+pub async fn count_history(
+    pool: &PgPool,
+    user_id: Uuid,
+    status_filter: Option<&str>,
+    source_type_filter: Option<&str>,
+) -> Result<i64, AppError> {
+    let row = sqlx::query_scalar::<_, i64>(
+        r#"
+        SELECT COUNT(*) FROM article_history
+        WHERE user_id = $1
+            AND ($2::TEXT IS NULL OR status = $2)
+            AND ($3::TEXT IS NULL OR source_type = $3)
+        "#,
+    )
+    .bind(user_id)
+    .bind(status_filter)
+    .bind(source_type_filter)
+    .fetch_one(pool)
+    .await?;
+    Ok(row)
+}
+
+/// List all article history entries for a generation job.
+pub async fn list_by_job_id(
+    pool: &PgPool,
+    user_id: Uuid,
+    job_id: Uuid,
+) -> Result<Vec<ArticleHistoryRow>, AppError> {
+    let rows = sqlx::query_as::<_, ArticleHistoryRow>(
+        r#"
+        SELECT id, url, title, source_type, source_url, category, synthesis_id, status, scraped_ok, job_id, created_at
+        FROM article_history
+        WHERE user_id = $1 AND job_id = $2
+        ORDER BY created_at ASC
+        "#,
+    )
+    .bind(user_id)
+    .bind(job_id)
+    .fetch_all(pool)
+    .await?;
+    Ok(rows)
+}
+
 /// Delete history entries older than N days for this user.
 ///
+/// Only removes entries where synthesis_id IS NULL (dropped articles).
+/// Used articles linked to syntheses stay until the synthesis is deleted.
+///
 /// Returns the number of deleted rows.
 pub async fn cleanup_old(
     pool: &PgPool,
@@ -65,7 +199,7 @@ pub async fn cleanup_old(
     days: i32,
 ) -> Result<u64, AppError> {
     let result = sqlx::query(
-        "DELETE FROM article_history WHERE user_id = $1 AND created_at < now() - make_interval(days => $2)",
+        "DELETE FROM article_history WHERE user_id = $1 AND created_at < now() - make_interval(days => $2) AND synthesis_id IS NULL",
     )
     .bind(user_id)
     .bind(days)