import type { Database } from 'bun:sqlite';

export type Migration = {
  version: number;
  name: string;
  checksum: string; // estático para trazabilidad básica
  up: (db: Database) => void | Promise<void>;
};

function tableHasColumn(db: Database, table: string, column: string): boolean {
  const cols = db.query(`PRAGMA table_info(${table})`).all() as any[];
  return Array.isArray(cols) && cols.some((c: any) => c.name === column);
}

export const migrations: Migration[] = [
  {
    version: 1,
    name: 'initial-schema',
    checksum: 'v1-initial-schema-2025-09-06',
    up: (db: Database) => {
      // Esquema inicial (equivalente al initializeDatabase actual)
      db.exec(`PRAGMA foreign_keys = ON;`);

      db.exec(`
        CREATE TABLE IF NOT EXISTS users (
          id TEXT PRIMARY KEY,
          first_seen TEXT DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
          last_seen TEXT DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now'))
        );
      `);

      db.exec(`
        CREATE TABLE IF NOT EXISTS groups (
          id TEXT PRIMARY KEY,
          community_id TEXT NOT NULL,
          name TEXT,
          last_verified TEXT DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
          active BOOLEAN DEFAULT TRUE
        );
      `);

      db.exec(`
        CREATE TABLE IF NOT EXISTS tasks (
          id INTEGER PRIMARY KEY AUTOINCREMENT,
          description TEXT NOT NULL,
          created_at TEXT DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
          due_date TEXT NULL,
          completed BOOLEAN DEFAULT FALSE,
          completed_at TEXT NULL,
          group_id TEXT NULL,
          created_by TEXT NOT NULL,
          completed_by TEXT NULL,
          FOREIGN KEY (created_by) REFERENCES users(id) ON DELETE CASCADE,
          FOREIGN KEY (completed_by) REFERENCES users(id) ON DELETE SET NULL,
          FOREIGN KEY (group_id) REFERENCES groups(id) ON DELETE SET NULL
        );
      `);

      db.exec(`
        CREATE TABLE IF NOT EXISTS task_assignments (
          task_id INTEGER NOT NULL,
          user_id TEXT NOT NULL,
          assigned_by TEXT NOT NULL,
          assigned_at TEXT DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
          PRIMARY KEY (task_id, user_id),
          FOREIGN KEY (task_id) REFERENCES tasks(id) ON DELETE CASCADE,
          FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
          FOREIGN KEY (assigned_by) REFERENCES users(id) ON DELETE CASCADE
        );
      `);

      db.exec(`
        CREATE TABLE IF NOT EXISTS response_queue (
          id INTEGER PRIMARY KEY AUTOINCREMENT,
          recipient TEXT NOT NULL,
          message TEXT NOT NULL,
          status TEXT NOT NULL DEFAULT 'queued' CHECK (status IN ('queued','processing','sent','failed')),
          attempts INTEGER NOT NULL DEFAULT 0,
          last_error TEXT NULL,
          metadata TEXT NULL,
          created_at TEXT DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
          updated_at TEXT DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now'))
        );
      `);

      db.exec(`
        CREATE INDEX IF NOT EXISTS idx_response_queue_status_created_at
        ON response_queue (status, created_at);
      `);
    }
  },
  {
    version: 2,
    name: 'response-queue-reliability',
    checksum: 'v2-rq-reliability-2025-09-06',
    up: (db: Database) => {
      // Añadir columnas necesarias si no existen (idempotente)
      if (!tableHasColumn(db, 'response_queue', 'next_attempt_at')) {
        db.exec(`ALTER TABLE response_queue ADD COLUMN next_attempt_at TEXT NULL;`);
      }
      if (!tableHasColumn(db, 'response_queue', 'lease_until')) {
        db.exec(`ALTER TABLE response_queue ADD COLUMN lease_until TEXT NULL;`);
      }
      if (!tableHasColumn(db, 'response_queue', 'last_status_code')) {
        db.exec(`ALTER TABLE response_queue ADD COLUMN last_status_code INTEGER NULL;`);
      }

      // Índices complementarios
      db.exec(`
        CREATE INDEX IF NOT EXISTS idx_response_queue_status_next_attempt
        ON response_queue (status, next_attempt_at);
      `);
      db.exec(`
        CREATE INDEX IF NOT EXISTS idx_response_queue_status_lease_until
        ON response_queue (status, lease_until);
      `);
    }
  },
  {
    version: 3,
    name: 'response-queue-retention-index',
    checksum: 'v3-rq-retention-index-2025-09-06',
    up: (db: Database) => {
      db.exec(`
        CREATE INDEX IF NOT EXISTS idx_response_queue_status_updated_at
        ON response_queue (status, updated_at);
      `);
    }
  },
  {
    version: 4,
    name: 'user-preferences-reminders',
    checksum: 'v4-user-preferences-2025-09-07',
    up: (db: Database) => {
      db.exec(`
        CREATE TABLE IF NOT EXISTS user_preferences (
          user_id TEXT PRIMARY KEY,
          reminder_freq TEXT NOT NULL DEFAULT 'off' CHECK (reminder_freq IN ('off','daily','weekly')),
          reminder_time TEXT NOT NULL DEFAULT '08:30',
          last_reminded_on TEXT NULL,
          updated_at TEXT DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
          FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
        );
      `);
      db.exec(`
        CREATE INDEX IF NOT EXISTS idx_user_prefs_freq_time
        ON user_preferences (reminder_freq, reminder_time);
      `);
    }
  },
  {
    version: 5,
    name: 'group-membership',
    checksum: 'v5-group-membership-2025-09-07',
    up: (db: Database) => {
      db.exec(`PRAGMA foreign_keys = ON;`);
      db.exec(`
        CREATE TABLE IF NOT EXISTS group_members (
          group_id TEXT NOT NULL,
          user_id TEXT NOT NULL,
          is_admin BOOLEAN NOT NULL DEFAULT 0,
          is_active BOOLEAN NOT NULL DEFAULT 1,
          first_seen_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
          last_seen_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
          last_role_change_at TEXT NULL,
          PRIMARY KEY (group_id, user_id),
          FOREIGN KEY (group_id) REFERENCES groups(id) ON DELETE CASCADE,
          FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
        );
      `);
      db.exec(`
        CREATE INDEX IF NOT EXISTS idx_group_members_group_active
        ON group_members (group_id, is_active);
      `);
      db.exec(`
        CREATE INDEX IF NOT EXISTS idx_group_members_user_active
        ON group_members (user_id, is_active);
      `);
    }
  },
  {
    version: 6,
    name: 'user-aliases',
    checksum: 'v6-user-aliases-2025-09-20',
    up: (db: Database) => {
      db.exec(`
        CREATE TABLE IF NOT EXISTS user_aliases (
          alias TEXT PRIMARY KEY,
          user_id TEXT NOT NULL,
          source TEXT NULL,
          created_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
          updated_at TEXT NOT NULL DEFAULT (strftime('%Y-%m-%d %H:%M:%f', 'now')),
          FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
        );
      `);
      db.exec(`
        CREATE INDEX IF NOT EXISTS idx_user_aliases_user_id
        ON user_aliases (user_id);
      `);
    }
  }
];