import Database from "better-sqlite3";
import path from "path";
import { fileURLToPath } from "url";

const __dirname = path.dirname(fileURLToPath(import.meta.url));
const DB_PATH = path.join(__dirname, "../../events.db");

let _db: Database.Database | null = null;

function getDb(): Database.Database {
  if (!_db) {
    _db = new Database(DB_PATH);
    _db.pragma("journal_mode = WAL");
    _db.pragma("foreign_keys = ON");
    initSchema(_db);
  }
  return _db;
}

function initSchema(db: Database.Database) {
  db.exec(`
    CREATE TABLE IF NOT EXISTS venues (
      id    TEXT PRIMARY KEY,
      name  TEXT NOT NULL,
      url   TEXT NOT NULL,
      area  TEXT
    );

    CREATE TABLE IF NOT EXISTS events (
      id          INTEGER PRIMARY KEY AUTOINCREMENT,
      venue_id    TEXT    NOT NULL REFERENCES venues(id),
      title       TEXT    NOT NULL,
      artist      TEXT,
      date        TEXT    NOT NULL,
      start_time  TEXT,
      open_time   TEXT,
      ticket_url  TEXT,
      price       TEXT,
      image_url   TEXT,
      description TEXT,
      source_url  TEXT,
      fetched_at  TEXT    NOT NULL DEFAULT (datetime('now')),
      UNIQUE(venue_id, title, date)
    );

    CREATE INDEX IF NOT EXISTS idx_events_date     ON events(date);
    CREATE INDEX IF NOT EXISTS idx_events_venue_id ON events(venue_id);
  `);
}

export interface Venue {
  id: string;
  name: string;
  url: string;
  area: string | null;
  event_count?: number;
}

export interface Event {
  id: number;
  venue_id: string;
  venue_name: string;
  venue_area: string | null;
  venue_url?: string;
  title: string;
  artist: string | null;
  date: string;
  start_time: string | null;
  open_time: string | null;
  ticket_url: string | null;
  price: string | null;
  image_url: string | null;
  description: string | null;
  source_url: string | null;
  fetched_at: string;
}

export interface EventInput {
  venue_id: string;
  title: string;
  artist?: string | null;
  date: string;
  start_time?: string | null;
  open_time?: string | null;
  ticket_url?: string | null;
  price?: string | null;
  image_url?: string | null;
  description?: string | null;
  source_url?: string | null;
}

export function upsertVenue(
  id: string,
  name: string,
  url: string,
  area?: string
) {
  getDb()
    .prepare(
      "INSERT OR REPLACE INTO venues (id, name, url, area) VALUES (?, ?, ?, ?)"
    )
    .run(id, name, url, area ?? null);
}

export function upsertEvent(event: EventInput) {
  getDb()
    .prepare(
      `INSERT INTO events
        (venue_id, title, artist, date, start_time, open_time,
         ticket_url, price, image_url, description, source_url, fetched_at)
       VALUES
        (@venue_id, @title, @artist, @date, @start_time, @open_time,
         @ticket_url, @price, @image_url, @description, @source_url, datetime('now'))
       ON CONFLICT(venue_id, title, date) DO UPDATE SET
         artist      = excluded.artist,
         start_time  = excluded.start_time,
         open_time   = excluded.open_time,
         ticket_url  = excluded.ticket_url,
         price       = excluded.price,
         image_url   = excluded.image_url,
         description = excluded.description,
         source_url  = excluded.source_url,
         fetched_at  = excluded.fetched_at`
    )
    .run(event);
}

export interface QueryEventsParams {
  date_from?: string;
  date_to?: string;
  venue_id?: string;
  keyword?: string;
  limit?: number;
  offset?: number;
}

export function queryEvents(params: QueryEventsParams = {}): Event[] {
  const { date_from, date_to, venue_id, keyword, limit = 60, offset = 0 } =
    params;

  const clauses: string[] = [];
  const args: unknown[] = [];

  if (date_from) {
    clauses.push("e.date >= ?");
    args.push(date_from);
  }
  if (date_to) {
    clauses.push("e.date <= ?");
    args.push(date_to);
  }
  if (venue_id) {
    clauses.push("e.venue_id = ?");
    args.push(venue_id);
  }
  if (keyword) {
    clauses.push("(e.title LIKE ? OR e.artist LIKE ?)");
    args.push(`%${keyword}%`, `%${keyword}%`);
  }

  const where = clauses.length ? `WHERE ${clauses.join(" AND ")}` : "";

  return getDb()
    .prepare(
      `SELECT e.*, v.name AS venue_name, v.area AS venue_area
       FROM events e JOIN venues v ON e.venue_id = v.id
       ${where}
       ORDER BY e.date ASC, e.start_time ASC
       LIMIT ? OFFSET ?`
    )
    .all(...args, limit, offset) as Event[];
}

export function getEvent(id: number): Event | undefined {
  return getDb()
    .prepare(
      `SELECT e.*, v.name AS venue_name, v.url AS venue_url, v.area AS venue_area
       FROM events e JOIN venues v ON e.venue_id = v.id
       WHERE e.id = ?`
    )
    .get(id) as Event | undefined;
}

export function getVenues(): Venue[] {
  return getDb()
    .prepare(
      `SELECT v.*, COUNT(e.id) AS event_count
       FROM venues v LEFT JOIN events e ON v.id = e.venue_id
       GROUP BY v.id ORDER BY v.name`
    )
    .all() as Venue[];
}