use axum::{
    extract::{Path, State},
    Json,
};
use serde_json::{json, Value};

use crate::{
    app::AppState,
    error::{AppError, AppResult},
    services::{
        club as club_svc, notification as notif_svc, objective as obj_svc, profile as profile_svc,
    },
};

/// GET /notifications
///
/// Returns persistent (event-driven) notifications merged with dynamic state
/// notifications (unclaimed objectives, expiring loans, season ending soon).
/// Persistent notifications carry an `id` and `is_read` flag; dynamic ones
/// have `id: null` and are always considered unread.
pub async fn get_notifications(State(state): State<AppState>) -> AppResult<Json<Value>> {
    let profile = profile_svc::get_active_profile(&state.pool).await?;
    let club = club_svc::get_club_by_profile(&state.pool, &profile.id).await?;

    // ── Persistent notifications ─────────────────────────────────────────────
    let persistent = notif_svc::list(&state.pool).await?;
    let persistent_unread = persistent.iter().filter(|n| !n.is_read).count() as i64;

    // ── Dynamic: unclaimed objective rewards ─────────────────────────────────
    let objectives =
        obj_svc::get_objectives_with_progress(&state.pool, &profile.id, &state.obj_defs).await?;
    let mut dynamic: Vec<Value> = objectives
        .iter()
        .filter(|o| o.completed && !o.claimed)
        .map(|o| json!({
            "id": null,
            "type": "objective_complete",
            "title": format!("Objective complete: {}", o.definition.title),
            "body": format!("Claim your reward for \"{}\" (+{} coins)", o.definition.title, o.definition.reward_coins),
            "is_read": false,
            "created_at": null,
        }))
        .collect();

    // ── Dynamic: loan cards expiring within 2 matches ────────────────────────
    let expiring: Vec<(String, String, Option<i64>)> = sqlx::query_as(
        "SELECT oc.id, oc.card_id, oc.loan_matches_remaining \
         FROM owned_cards oc WHERE oc.club_id = ? AND oc.is_loan = 1 \
         AND oc.loan_matches_remaining IS NOT NULL AND oc.loan_matches_remaining <= 2",
    )
    .bind(&club.id)
    .fetch_all(&state.pool)
    .await?;

    for (owned_id, card_id, remaining) in expiring {
        let card_name = state
            .card_db
            .get(&card_id)
            .map(|c| c.name.clone())
            .unwrap_or_else(|| card_id.clone());
        dynamic.push(json!({
            "id": null,
            "type": "loan_expiring",
            "title": format!("Loan expiring: {card_name}"),
            "body": format!("{card_name} has {} match(es) remaining on loan.", remaining.unwrap_or(0)),
            "is_read": false,
            "created_at": null,
            "owned_card_id": owned_id,
        }));
    }

    // ── Dynamic: season ending soon ──────────────────────────────────────────
    let season_row: Option<(i64, i64)> =
        sqlx::query_as("SELECT matches_played, division FROM seasons WHERE profile_id = ?")
            .bind(&profile.id)
            .fetch_optional(&state.pool)
            .await?;

    if let Some((played, division)) = season_row {
        let remaining = (10 - played).max(0);
        if remaining <= 2 && remaining > 0 {
            dynamic.push(json!({
                "id": null,
                "type": "season_ending",
                "title": format!("Season ending — Division {division}"),
                "body": format!("{remaining} match(es) left in the current season."),
                "is_read": false,
                "created_at": null,
            }));
        }
    }

    // ── Merge: persistent first (newest first), then dynamic ─────────────────
    // Use "type" key for compatibility with dashboard and existing tests.
    let all: Vec<Value> = persistent
        .iter()
        .map(|n| {
            json!({
                "id": n.id,
                "type": n.kind,
                "title": n.title,
                "body": n.body,
                "is_read": n.is_read,
                "created_at": n.created_at,
            })
        })
        .chain(dynamic.iter().cloned())
        .collect();

    let total_unread = persistent_unread + dynamic.len() as i64;

    Ok(Json(json!({
        "notifications": all,
        "unread_count": total_unread,
    })))
}

/// PATCH /notifications/:id/read
pub async fn mark_notification_read(
    State(state): State<AppState>,
    Path(id): Path<String>,
) -> AppResult<Json<Value>> {
    let found = notif_svc::mark_read(&state.pool, &id).await?;
    if !found {
        return Err(AppError::NotFound(format!("notification '{id}' not found")));
    }
    Ok(Json(json!({ "marked_read": id })))
}

/// POST /notifications/read-all
pub async fn mark_all_notifications_read(State(state): State<AppState>) -> AppResult<Json<Value>> {
    let count = notif_svc::mark_all_read(&state.pool).await?;
    Ok(Json(json!({ "marked_read": count })))
}