//! LLM call logging: tracks every LLM interaction during synthesis generation.

use chrono::{DateTime, Utc};
use serde::Serialize;
use sqlx::PgPool;
use uuid::Uuid;

use crate::errors::AppError;

/// Row returned from llm_call_log queries.
#[derive(Debug, Clone, Serialize, sqlx::FromRow)]
pub struct LlmCallLogRow {
    pub id: Uuid,
    pub call_type: String,
    pub model: String,
    pub system_prompt: String,
    pub user_prompt: String,
    pub response_body: String,
    pub duration_ms: i32,
    pub article_url: Option<String>,
    pub created_at: DateTime<Utc>,
}

/// Insert a single LLM call log entry.
#[allow(clippy::too_many_arguments)]
pub async fn insert(
    pool: &PgPool,
    user_id: Uuid,
    job_id: Uuid,
    call_type: &str,
    model: &str,
    system_prompt: &str,
    user_prompt: &str,
    response_body: &str,
    duration_ms: i32,
    article_url: Option<&str>,
) -> Result<(), AppError> {
    sqlx::query(
        r#"
        INSERT INTO llm_call_log (user_id, job_id, call_type, model, system_prompt, user_prompt, response_body, duration_ms, article_url)
        VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
        "#,
    )
    .bind(user_id)
    .bind(job_id)
    .bind(call_type)
    .bind(model)
    .bind(system_prompt)
    .bind(user_prompt)
    .bind(response_body)
    .bind(duration_ms)
    .bind(article_url)
    .execute(pool)
    .await?;
    Ok(())
}

/// List all LLM call log entries for a generation job.
pub async fn list_by_job_id(
    pool: &PgPool,
    user_id: Uuid,
    job_id: Uuid,
) -> Result<Vec<LlmCallLogRow>, AppError> {
    let rows = sqlx::query_as::<_, LlmCallLogRow>(
        r#"
        SELECT id, call_type, model, system_prompt, user_prompt, response_body, duration_ms, article_url, created_at
        FROM llm_call_log
        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)
}

/// Truncate old LLM call log entries: replace prompt/response with first 500 chars.
pub async fn truncate_old(
    pool: &PgPool,
    user_id: Uuid,
    days: i32,
) -> Result<u64, AppError> {
    let result = sqlx::query(
        r#"
        UPDATE llm_call_log
        SET system_prompt = LEFT(system_prompt, 500) || E'\n[truncated]',
            user_prompt = LEFT(user_prompt, 500) || E'\n[truncated]',
            response_body = LEFT(response_body, 500) || E'\n[truncated]'
        WHERE user_id = $1
            AND created_at < now() - make_interval(days => $2)
            AND LENGTH(system_prompt) > 510
        "#,
    )
    .bind(user_id)
    .bind(days)
    .execute(pool)
    .await?;
    Ok(result.rows_affected())
}