// Phase 4 — reshape rooms into a unified "conversations" model (direct + group)
// and add contacts. Renames preserve existing group data (existing rooms become
// type='group').

/** @param {import('node-pg-migrate').MigrationBuilder} pgm */
exports.up = (pgm) => {
  // rooms -> conversations
  pgm.renameTable('rooms', 'conversations');
  pgm.renameColumn('conversations', 'name', 'title');
  pgm.alterColumn('conversations', 'title', { notNull: false });
  pgm.addColumns('conversations', {
    type: { type: 'text', notNull: true, default: 'group' },
    // Canonical sorted user-pair for a direct conversation; unique so a 1:1 is
    // never duplicated. NULL for groups (Postgres allows many NULLs in UNIQUE).
    direct_key: { type: 'text' },
    last_message_at: { type: 'timestamptz', notNull: true, default: pgm.func('now()') },
  });
  pgm.addConstraint('conversations', 'conversations_direct_key_uq', { unique: ['direct_key'] });

  // room_members -> conversation_members
  pgm.renameTable('room_members', 'conversation_members');
  pgm.renameColumn('conversation_members', 'room_id', 'conversation_id');

  // messages.room_id -> conversation_id (indexes + dedupe constraint follow the rename)
  pgm.renameColumn('messages', 'room_id', 'conversation_id');

  pgm.createTable('contacts', {
    owner_id: { type: 'uuid', notNull: true, references: 'users', onDelete: 'CASCADE' },
    contact_id: { type: 'uuid', notNull: true, references: 'users', onDelete: 'CASCADE' },
    created_at: { type: 'timestamptz', notNull: true, default: pgm.func('now()') },
  });
  pgm.addConstraint('contacts', 'contacts_pkey', { primaryKey: ['owner_id', 'contact_id'] });
};

/** @param {import('node-pg-migrate').MigrationBuilder} pgm */
exports.down = (pgm) => {
  pgm.dropTable('contacts');
  pgm.renameColumn('messages', 'conversation_id', 'room_id');
  pgm.renameColumn('conversation_members', 'conversation_id', 'room_id');
  pgm.renameTable('conversation_members', 'room_members');
  pgm.dropConstraint('conversations', 'conversations_direct_key_uq');
  pgm.dropColumns('conversations', ['type', 'direct_key', 'last_message_at']);
  pgm.alterColumn('conversations', 'title', { notNull: true });
  pgm.renameColumn('conversations', 'title', 'name');
  pgm.renameTable('conversations', 'rooms');
};