import type Database from "better-sqlite3";

export function runMigrations(db: Database.Database): void {
  db.exec(`
    CREATE TABLE IF NOT EXISTS users (
      id             INTEGER PRIMARY KEY AUTOINCREMENT,
      email          TEXT UNIQUE NOT NULL,
      password_hash  TEXT NOT NULL,
      display_name   TEXT NOT NULL,
      role           TEXT NOT NULL DEFAULT 'user',
      email_verified INTEGER DEFAULT 0,
      verify_token   TEXT,
      verify_expires INTEGER,
      reset_token    TEXT,
      reset_expires  INTEGER,
      created_at     INTEGER DEFAULT (unixepoch()),
      updated_at     INTEGER DEFAULT (unixepoch())
    );

    CREATE TABLE IF NOT EXISTS saved_exams (
      id          INTEGER PRIMARY KEY AUTOINCREMENT,
      user_id     INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
      title       TEXT NOT NULL,
      subtitle    TEXT,
      exam_json   TEXT NOT NULL,
      created_at  INTEGER DEFAULT (unixepoch()),
      updated_at  INTEGER DEFAULT (unixepoch())
    );

    CREATE TABLE IF NOT EXISTS exam_results (
      id            INTEGER PRIMARY KEY AUTOINCREMENT,
      user_id       INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
      exam_id       INTEGER REFERENCES saved_exams(id) ON DELETE SET NULL,
      title         TEXT NOT NULL,
      score_points  REAL NOT NULL,
      total_points  REAL NOT NULL,
      correct_count INTEGER NOT NULL,
      graded_count  INTEGER NOT NULL,
      passing_score REAL DEFAULT 60,
      elapsed_ms    INTEGER NOT NULL,
      state_json    TEXT NOT NULL,
      exam_json     TEXT NOT NULL,
      completed_at  INTEGER DEFAULT (unixepoch())
    );

    CREATE TABLE IF NOT EXISTS site_settings (
      key        TEXT PRIMARY KEY,
      value      TEXT NOT NULL,
      updated_at INTEGER DEFAULT (unixepoch())
    );

    CREATE INDEX IF NOT EXISTS idx_saved_exams_user ON saved_exams(user_id);
    CREATE INDEX IF NOT EXISTS idx_exam_results_user ON exam_results(user_id);
  `);

  // ── Add share_token and is_public columns if missing ──
  const examCols = db.prepare(`PRAGMA table_info(saved_exams)`).all() as { name: string }[];
  if (!examCols.some((c) => c.name === 'share_token')) {
    db.exec(`ALTER TABLE saved_exams ADD COLUMN share_token TEXT`);
  }
  if (!examCols.some((c) => c.name === 'is_public')) {
    db.exec(`ALTER TABLE saved_exams ADD COLUMN is_public INTEGER DEFAULT 0`);
  }

  db.exec(`
    CREATE UNIQUE INDEX IF NOT EXISTS idx_saved_exams_share ON saved_exams(share_token);
  `);

  // ── Add role column if missing (existing databases) ──
  const cols = db.prepare(`PRAGMA table_info(users)`).all() as {
    name: string;
  }[];
  if (!cols.some((c) => c.name === "role")) {
    db.exec(`ALTER TABLE users ADD COLUMN role TEXT NOT NULL DEFAULT 'user'`);
  }

    // ── Add storage_quota_bytes if missing ──
    if (!cols.some((c) => c.name === "storage_quota_bytes")) {
      db.exec(`ALTER TABLE users ADD COLUMN storage_quota_bytes INTEGER NOT NULL DEFAULT 1073741824`);
    }

    // ── Add plan if missing ──
    if (!cols.some((c) => c.name === "plan")) {
      db.exec(`ALTER TABLE users ADD COLUMN plan TEXT NOT NULL DEFAULT 'free'`);
    }

    // ── Add is_favorite to saved_exams if missing ──
    const examSavedCols = db.prepare(`PRAGMA table_info(saved_exams)`).all() as { name: string }[];
    if (!examSavedCols.some((c) => c.name === 'is_favorite')) {
      db.exec(`ALTER TABLE saved_exams ADD COLUMN is_favorite INTEGER DEFAULT 0`);
    }

    // ── Add tags to saved_exams if missing ──
    if (!examSavedCols.some((c) => c.name === 'tags')) {
      db.exec(`ALTER TABLE saved_exams ADD COLUMN tags TEXT DEFAULT '[]'`);
    }

    // ── Add collection_id to saved_exams if missing ──
    if (!examSavedCols.some((c) => c.name === 'collection_id')) {
      db.exec(`ALTER TABLE saved_exams ADD COLUMN collection_id INTEGER REFERENCES collections(id) ON DELETE SET NULL`);
    }

    // ── Add share_mode to saved_exams if missing ──
    if (!examSavedCols.some((c) => c.name === 'share_mode')) {
      db.exec(`ALTER TABLE saved_exams ADD COLUMN share_mode TEXT DEFAULT 'clone'`);
    }

    // ── Add cloned_from_share_token to saved_exams if missing ──
    if (!examSavedCols.some((c) => c.name === 'cloned_from_share_token')) {
      db.exec(`ALTER TABLE saved_exams ADD COLUMN cloned_from_share_token TEXT`);
    }

    // ── Collections table ──
    db.exec(`
      CREATE TABLE IF NOT EXISTS collections (
        id          INTEGER PRIMARY KEY AUTOINCREMENT,
        user_id     INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
        name        TEXT NOT NULL,
        created_at  INTEGER DEFAULT (unixepoch()),
        updated_at  INTEGER DEFAULT (unixepoch())
      );
      CREATE INDEX IF NOT EXISTS idx_collections_user ON collections(user_id);
    `);

  // ── Promote first user to admin if no admins exist ──
  const adminCount = db
    .prepare(`SELECT COUNT(*) AS cnt FROM users WHERE role = 'admin'`)
    .get() as { cnt: number };
  if (adminCount.cnt === 0) {
    db.prepare(
      `UPDATE users SET role = 'admin' WHERE id = (SELECT MIN(id) FROM users)`,
    ).run();
  }

  // ── Seed default settings ──
  const defaults: Record<string, string> = {
    site_name: "BrainWave",
    max_upload_mb: "5",
    allow_guest_mode: "true",
    registration_enabled: "true",
    default_theme: "light",
    maintenance_mode: "false",
    maintenance_message:
      "We are currently performing maintenance. Please check back soon.",
    smtp_host: "",
    smtp_port: "587",
    smtp_user: "",
    smtp_pass: "",
    smtp_from: "BrainWave <noreply@brainwave.local>",
    smtp_secure: "auto",
    app_url: "http://localhost:5173",
  };
  const upsert = db.prepare(`
    INSERT INTO site_settings (key, value) VALUES (?, ?)
    ON CONFLICT(key) DO NOTHING
  `);
  for (const [key, value] of Object.entries(defaults)) {
    upsert.run(key, value);
  }
}