import { MigrationInterface, QueryRunner } from "typeorm";

/**
 * Customer-support chat. A `support_conversations` row is the single ongoing
 * thread with a company; `support_messages` are its text messages. There is no
 * lifecycle column — a thread is opened by whichever side speaks first and
 * stays open. Enum-like columns are varchar (no PG enum churn).
 *
 * The unique index on `company_id` is load-bearing, not just an optimization:
 * the get-or-create path depends on it to settle concurrent first-messages.
 * It is partial on `deleted_at IS NULL` so a soft-deleted thread doesn't block
 * a fresh one.
 */
export class CreateSupportChat2310000000000 implements MigrationInterface {
  name = "CreateSupportChat2310000000000";

  public async up(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.query(`
      CREATE TABLE IF NOT EXISTS freight.support_conversations (
        id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
        company_id uuid NOT NULL,
        company_name varchar(200),
        created_by_user_id uuid,
        last_message_at timestamptz,
        last_message_preview varchar(280),
        last_message_author_role varchar(12),
        customer_last_read_at timestamptz,
        agent_last_read_at timestamptz,
        created_at timestamptz NOT NULL DEFAULT now(),
        updated_at timestamptz NOT NULL DEFAULT now(),
        deleted_at timestamptz
      )
    `);
    await queryRunner.query(`
      CREATE UNIQUE INDEX IF NOT EXISTS "IDX_SUPPORT_CONV_COMPANY"
      ON freight.support_conversations (company_id)
      WHERE deleted_at IS NULL
    `);
    await queryRunner.query(`
      CREATE INDEX IF NOT EXISTS "IDX_SUPPORT_CONV_LASTMSG"
      ON freight.support_conversations (last_message_at)
    `);

    await queryRunner.query(`
      CREATE TABLE IF NOT EXISTS freight.support_messages (
        id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
        conversation_id uuid NOT NULL,
        author_user_id uuid NOT NULL,
        author_role varchar(12) NOT NULL,
        author_name varchar(200),
        body text NOT NULL,
        created_at timestamptz NOT NULL DEFAULT now(),
        updated_at timestamptz NOT NULL DEFAULT now(),
        deleted_at timestamptz
      )
    `);
    await queryRunner.query(`
      CREATE INDEX IF NOT EXISTS "IDX_SUPPORT_MSG_CONV_CREATED"
      ON freight.support_messages (conversation_id, created_at)
    `);
  }

  public async down(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.query(
      `DROP INDEX IF EXISTS freight."IDX_SUPPORT_MSG_CONV_CREATED"`,
    );
    await queryRunner.query(`DROP TABLE IF EXISTS freight.support_messages`);
    await queryRunner.query(
      `DROP INDEX IF EXISTS freight."IDX_SUPPORT_CONV_LASTMSG"`,
    );
    await queryRunner.query(
      `DROP INDEX IF EXISTS freight."IDX_SUPPORT_CONV_COMPANY"`,
    );
    await queryRunner.query(
      `DROP TABLE IF EXISTS freight.support_conversations`,
    );
  }
}