use axum::{extract::State, Json};

use super::{AppError, AppState};

pub async fn get_stats(
    State(state): State<AppState>,
) -> Result<Json<serde_json::Value>, AppError> {
    // Total sessions
    let total_sessions: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM imaging_log")
        .fetch_one(&state.pool)
        .await?;

    // Total integration time
    let total_integration_min: Option<i64> =
        sqlx::query_scalar("SELECT SUM(integration_min) FROM imaging_log")
            .fetch_optional(&state.pool)
            .await?
            .flatten();

    // Objects imaged (at least one keeper)
    let objects_with_keeper: i64 = sqlx::query_scalar(
        "SELECT COUNT(DISTINCT catalog_id) FROM imaging_log WHERE quality = 'keeper'",
    )
    .fetch_one(&state.pool)
    .await?;

    // Filter usage
    let filter_usage = sqlx::query(
        "SELECT filter_id, COUNT(*) as count, SUM(integration_min) as total_min FROM imaging_log GROUP BY filter_id",
    )
    .fetch_all(&state.pool)
    .await?;

    let filter_stats: Vec<serde_json::Value> = filter_usage.iter().map(|r| {
        use sqlx::Row;
        serde_json::json!({
            "filter_id": r.try_get::<String, _>("filter_id").unwrap_or_default(),
            "count": r.try_get::<i64, _>("count").unwrap_or_default(),
            "total_min": r.try_get::<Option<i64>, _>("total_min").unwrap_or_default(),
        })
    }).collect();

    // Integration per month (last 12 months)
    let monthly = sqlx::query(
        r#"SELECT substr(session_date, 1, 7) as month,
               COUNT(*) as sessions,
               SUM(integration_min) as total_min
           FROM imaging_log
           WHERE session_date >= date('now', '-12 months')
           GROUP BY month
           ORDER BY month"#,
    )
    .fetch_all(&state.pool)
    .await?;

    let monthly_stats: Vec<serde_json::Value> = monthly.iter().map(|r| {
        use sqlx::Row;
        serde_json::json!({
            "month": r.try_get::<String, _>("month").unwrap_or_default(),
            "sessions": r.try_get::<i64, _>("sessions").unwrap_or_default(),
            "total_min": r.try_get::<Option<i64>, _>("total_min").unwrap_or_default(),
        })
    }).collect();

    // Object type breakdown
    let type_breakdown = sqlx::query(
        r#"SELECT c.obj_type, COUNT(*) as sessions, SUM(l.integration_min) as total_min
           FROM imaging_log l JOIN catalog c ON c.id = l.catalog_id
           GROUP BY c.obj_type ORDER BY total_min DESC"#,
    )
    .fetch_all(&state.pool)
    .await?;

    let type_stats: Vec<serde_json::Value> = type_breakdown.iter().map(|r| {
        use sqlx::Row;
        serde_json::json!({
            "obj_type": r.try_get::<String, _>("obj_type").unwrap_or_default(),
            "sessions": r.try_get::<i64, _>("sessions").unwrap_or_default(),
            "total_min": r.try_get::<Option<i64>, _>("total_min").unwrap_or_default(),
        })
    }).collect();

    // Quality breakdown
    let quality = sqlx::query(
        "SELECT quality, COUNT(*) as count FROM imaging_log GROUP BY quality",
    )
    .fetch_all(&state.pool)
    .await?;

    let quality_stats: Vec<serde_json::Value> = quality.iter().map(|r| {
        use sqlx::Row;
        serde_json::json!({
            "quality": r.try_get::<String, _>("quality").unwrap_or_default(),
            "count": r.try_get::<i64, _>("count").unwrap_or_default(),
        })
    }).collect();

    // Top targets by integration
    let top_targets = sqlx::query(
        r#"SELECT c.id, c.name, c.common_name, c.obj_type,
               COUNT(l.id) as sessions,
               SUM(l.integration_min) as total_min
           FROM imaging_log l JOIN catalog c ON c.id = l.catalog_id
           GROUP BY l.catalog_id
           ORDER BY total_min DESC
           LIMIT 20"#,
    )
    .fetch_all(&state.pool)
    .await?;

    let top_target_list: Vec<serde_json::Value> = top_targets.iter().map(|r| {
        use sqlx::Row;
        serde_json::json!({
            "id": r.try_get::<String, _>("id").unwrap_or_default(),
            "name": r.try_get::<String, _>("name").unwrap_or_default(),
            "common_name": r.try_get::<Option<String>, _>("common_name").unwrap_or_default(),
            "obj_type": r.try_get::<String, _>("obj_type").unwrap_or_default(),
            "sessions": r.try_get::<i64, _>("sessions").unwrap_or_default(),
            "total_min": r.try_get::<Option<i64>, _>("total_min").unwrap_or_default(),
        })
    }).collect();

    // Guiding RMS over time
    let guiding = sqlx::query(
        "SELECT session_date, rms_total, rms_ra, rms_dec FROM phd2_logs ORDER BY session_date",
    )
    .fetch_all(&state.pool)
    .await?;

    let guiding_data: Vec<serde_json::Value> = guiding.iter().map(|r| {
        use sqlx::Row;
        serde_json::json!({
            "date": r.try_get::<String, _>("session_date").unwrap_or_default(),
            "rms_total": r.try_get::<Option<f64>, _>("rms_total").unwrap_or_default(),
            "rms_ra": r.try_get::<Option<f64>, _>("rms_ra").unwrap_or_default(),
            "rms_dec": r.try_get::<Option<f64>, _>("rms_dec").unwrap_or_default(),
        })
    }).collect();

    // Integration gap detector: targets with one narrowband filter but missing the companion.
    // Pairs: sv220 ↔ c2 (for full SHO palette), uvir ↔ sv260 (broadband pair).
    let gaps_raw = sqlx::query(
        r#"SELECT
               l.catalog_id,
               c.name,
               c.common_name,
               c.obj_type,
               SUM(CASE WHEN l.filter_id = 'sv220' THEN l.integration_min ELSE 0 END) as sv220_min,
               SUM(CASE WHEN l.filter_id = 'c2'    THEN l.integration_min ELSE 0 END) as c2_min,
               SUM(CASE WHEN l.filter_id = 'uvir'  THEN l.integration_min ELSE 0 END) as uvir_min,
               SUM(CASE WHEN l.filter_id = 'sv260' THEN l.integration_min ELSE 0 END) as sv260_min
           FROM imaging_log l
           JOIN catalog c ON c.id = l.catalog_id
           WHERE l.quality IN ('keeper', 'needs_more')
           GROUP BY l.catalog_id
           HAVING (sv220_min > 0 AND c2_min = 0)
               OR (c2_min > 0 AND sv220_min = 0)
               OR (uvir_min > 0 AND sv260_min = 0)
               OR (sv260_min > 0 AND uvir_min = 0)
           ORDER BY (sv220_min + c2_min + uvir_min + sv260_min) DESC
           LIMIT 10"#,
    )
    .fetch_all(&state.pool)
    .await?;

    let gaps: Vec<serde_json::Value> = gaps_raw.iter().map(|r| {
        use sqlx::Row;
        let sv220_min: i64 = r.try_get("sv220_min").unwrap_or(0);
        let c2_min: i64 = r.try_get("c2_min").unwrap_or(0);
        let uvir_min: i64 = r.try_get("uvir_min").unwrap_or(0);
        let sv260_min: i64 = r.try_get("sv260_min").unwrap_or(0);

        let mut missing: Vec<&str> = Vec::new();
        if sv220_min > 0 && c2_min == 0 { missing.push("c2"); }
        if c2_min > 0 && sv220_min == 0 { missing.push("sv220"); }
        if uvir_min > 0 && sv260_min == 0 { missing.push("sv260"); }
        if sv260_min > 0 && uvir_min == 0 { missing.push("uvir"); }

        serde_json::json!({
            "catalog_id": r.try_get::<String, _>("catalog_id").unwrap_or_default(),
            "name": r.try_get::<String, _>("name").unwrap_or_default(),
            "common_name": r.try_get::<Option<String>, _>("common_name").unwrap_or_default(),
            "obj_type": r.try_get::<String, _>("obj_type").unwrap_or_default(),
            "sv220_min": sv220_min,
            "c2_min": c2_min,
            "uvir_min": uvir_min,
            "sv260_min": sv260_min,
            "missing_filters": missing,
        })
    }).collect();

    // Catalogue completion: per-catalogue keeper counts vs total observable
    struct CatEntry { name: &'static str, sql_filter: &'static str }
    let catalogues: &[CatEntry] = &[
        CatEntry { name: "Messier",   sql_filter: "c.messier_num IS NOT NULL" },
        CatEntry { name: "Caldwell",  sql_filter: "c.caldwell_num IS NOT NULL" },
        CatEntry { name: "Sharpless", sql_filter: "c.id LIKE 'Sh2-%'" },
        CatEntry { name: "LDN",       sql_filter: "c.id LIKE 'LDN%'" },
        CatEntry { name: "VdB",       sql_filter: "c.id LIKE 'VdB%'" },
        CatEntry { name: "NGC",       sql_filter: "c.id LIKE 'NGC%'" },
        CatEntry { name: "IC",        sql_filter: "c.id LIKE 'IC%'" },
    ];

    let mut catalogue_completion: Vec<serde_json::Value> = Vec::new();
    for cat in catalogues {
        let total_sql = format!("SELECT COUNT(DISTINCT c.id) FROM catalog c WHERE {}", cat.sql_filter);
        let keeper_sql = format!(
            "SELECT COUNT(DISTINCT l.catalog_id) FROM imaging_log l JOIN catalog c ON c.id = l.catalog_id WHERE l.quality = 'keeper' AND {}",
            cat.sql_filter
        );
        let total: i64 = sqlx::query_scalar::<_, i64>(&total_sql)
            .fetch_one(&state.pool).await.unwrap_or(0);
        let keepers: i64 = sqlx::query_scalar::<_, i64>(&keeper_sql)
            .fetch_one(&state.pool).await.unwrap_or(0);
        if total > 0 {
            catalogue_completion.push(serde_json::json!({
                "name": cat.name,
                "total": total,
                "keepers": keepers,
                "pct": if total > 0 { (keepers as f64 / total as f64 * 100.0).round() as i64 } else { 0 },
            }));
        }
    }

    // Session history timeline: all sessions with first gallery image if available
    let history_rows = sqlx::query(
        r#"SELECT
               l.session_date,
               l.catalog_id,
               COALESCE(c.name, l.catalog_id) as name,
               c.common_name,
               c.obj_type,
               l.filter_id,
               l.integration_min,
               l.quality,
               l.notes,
               g.filename as gallery_filename
           FROM imaging_log l
           LEFT JOIN catalog c ON c.id = l.catalog_id
           LEFT JOIN (
               SELECT catalog_id, MIN(filename) as filename
               FROM gallery
               GROUP BY catalog_id
           ) g ON g.catalog_id = l.catalog_id
           ORDER BY l.session_date DESC, l.created_at DESC
           LIMIT 500"#,
    )
    .fetch_all(&state.pool)
    .await?;

    let history: Vec<serde_json::Value> = history_rows.iter().map(|r| {
        use sqlx::Row;
        let catalog_id: String = r.try_get("catalog_id").unwrap_or_default();
        let gallery_filename: Option<String> = r.try_get("gallery_filename").unwrap_or_default();
        let gallery_url = gallery_filename.map(|f| format!("/api/gallery/files/{}/{}", catalog_id, f));
        serde_json::json!({
            "date": r.try_get::<String, _>("session_date").unwrap_or_default(),
            "catalog_id": catalog_id,
            "name": r.try_get::<String, _>("name").unwrap_or_default(),
            "common_name": r.try_get::<Option<String>, _>("common_name").unwrap_or_default(),
            "obj_type": r.try_get::<Option<String>, _>("obj_type").unwrap_or_default(),
            "filter_id": r.try_get::<String, _>("filter_id").unwrap_or_default(),
            "integration_min": r.try_get::<i64, _>("integration_min").unwrap_or(0),
            "quality": r.try_get::<String, _>("quality").unwrap_or_default(),
            "notes": r.try_get::<Option<String>, _>("notes").unwrap_or_default(),
            "gallery_url": gallery_url,
        })
    }).collect();

    // Integration goals: keeper minutes per filter per target, for goal progress tracking
    let goals_raw = sqlx::query(
        r#"SELECT
               c.id, c.name, c.common_name, c.obj_type,
               SUM(CASE WHEN l.filter_id = 'sv220' AND l.quality = 'keeper' THEN l.integration_min ELSE 0 END) as sv220_min,
               SUM(CASE WHEN l.filter_id = 'c2'    AND l.quality = 'keeper' THEN l.integration_min ELSE 0 END) as c2_min,
               SUM(CASE WHEN l.filter_id = 'uvir'  AND l.quality = 'keeper' THEN l.integration_min ELSE 0 END) as uvir_min,
               SUM(CASE WHEN l.filter_id = 'sv260' AND l.quality = 'keeper' THEN l.integration_min ELSE 0 END) as sv260_min
           FROM imaging_log l
           JOIN catalog c ON c.id = l.catalog_id
           WHERE l.quality = 'keeper'
           GROUP BY l.catalog_id
           ORDER BY (sv220_min + c2_min + uvir_min + sv260_min) DESC
           LIMIT 30"#,
    )
    .fetch_all(&state.pool)
    .await?;

    let integration_goals: Vec<serde_json::Value> = goals_raw.iter().map(|r| {
        use sqlx::Row;
        serde_json::json!({
            "id":          r.try_get::<String, _>("id").unwrap_or_default(),
            "name":        r.try_get::<String, _>("name").unwrap_or_default(),
            "common_name": r.try_get::<Option<String>, _>("common_name").unwrap_or_default(),
            "obj_type":    r.try_get::<String, _>("obj_type").unwrap_or_default(),
            "sv220_min":   r.try_get::<i64, _>("sv220_min").unwrap_or(0),
            "c2_min":      r.try_get::<i64, _>("c2_min").unwrap_or(0),
            "uvir_min":    r.try_get::<i64, _>("uvir_min").unwrap_or(0),
            "sv260_min":   r.try_get::<i64, _>("sv260_min").unwrap_or(0),
        })
    }).collect();

    Ok(Json(serde_json::json!({
        "total_sessions": total_sessions,
        "total_integration_min": total_integration_min.unwrap_or(0),
        "objects_with_keeper": objects_with_keeper,
        "filter_usage": filter_stats,
        "monthly": monthly_stats,
        "by_type": type_stats,
        "quality": quality_stats,
        "top_targets": top_target_list,
        "guiding": guiding_data,
        "integration_gaps": gaps,
        "history": history,
        "catalogue_completion": catalogue_completion,
        "integration_goals": integration_goals,
    })))
}