// Phase 3 — rooms, membership, and messages.
// Messages use a crypto-agnostic content envelope so E2EE can be layered on
// later with no schema change (content holds plaintext now, ciphertext later).

/** @param {import('node-pg-migrate').MigrationBuilder} pgm */
exports.up = (pgm) => {
  pgm.createTable('rooms', {
    id: { type: 'uuid', primaryKey: true, default: pgm.func('gen_random_uuid()') },
    name: { type: 'text', notNull: true },
    created_by: { type: 'uuid', notNull: true, references: 'users', onDelete: 'RESTRICT' },
    created_at: { type: 'timestamptz', notNull: true, default: pgm.func('now()') },
  });

  pgm.createTable('room_members', {
    room_id: { type: 'uuid', notNull: true, references: 'rooms', onDelete: 'CASCADE' },
    user_id: { type: 'uuid', notNull: true, references: 'users', onDelete: 'CASCADE' },
    role: { type: 'text', notNull: true, default: 'member' },
    joined_at: { type: 'timestamptz', notNull: true, default: pgm.func('now()') },
  });
  pgm.addConstraint('room_members', 'room_members_pkey', {
    primaryKey: ['room_id', 'user_id'],
  });
  pgm.createIndex('room_members', 'user_id');

  pgm.createTable('messages', {
    id: { type: 'uuid', primaryKey: true, default: pgm.func('gen_random_uuid()') },
    // Server-assigned monotonic ordering.
    seq: { type: 'bigserial', notNull: true },
    room_id: { type: 'uuid', notNull: true, references: 'rooms', onDelete: 'CASCADE' },
    sender_id: { type: 'uuid', notNull: true, references: 'users', onDelete: 'RESTRICT' },
    // Client-generated idempotency / dedupe key.
    client_msg_id: { type: 'text', notNull: true },
    // Opaque content envelope (see file header).
    content: { type: 'text', notNull: true },
    content_type: { type: 'text', notNull: true, default: 'text' },
    encryption: { type: 'text' },
    created_at: { type: 'timestamptz', notNull: true, default: pgm.func('now()') },
  });
  pgm.createIndex('messages', 'seq', { unique: true });
  pgm.createIndex('messages', ['room_id', 'seq']);
  // Idempotent sends: one message per (room, sender, client_msg_id).
  pgm.addConstraint('messages', 'messages_dedupe_uq', {
    unique: ['room_id', 'sender_id', 'client_msg_id'],
  });
};

/** @param {import('node-pg-migrate').MigrationBuilder} pgm */
exports.down = (pgm) => {
  pgm.dropTable('messages');
  pgm.dropTable('room_members');
  pgm.dropTable('rooms');
};