import { MigrationInterface, QueryRunner } from "typeorm";

/**
 * Maker–checker for manual actions on shipping-line credit invoices.
 *
 * A shipping-line credit invoice is normally settled by the CBE webhook. Two
 * manual paths exist for finance: recording an offline payment (MARK_PAID)
 * and voiding an invoice raised in error (CANCEL, which releases its credits
 * back to the unbilled pool). Both erase or move real debt, so neither is a
 * single-person action: one permission raises the request, a different
 * permission — held by a chief, and never the requester themselves — approves
 * or rejects it. Rows are never deleted; decided requests are the audit trail.
 *
 * One PENDING row per invoice at a time (partial unique index): a second
 * request while one is undecided is a coordination failure, not a workflow.
 */
export class ShippingLineInvoiceApprovals3530000000000
  implements MigrationInterface
{
  public async up(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.query(`
      DO $$ BEGIN
        CREATE TYPE freight.shipping_line_invoice_approvals_action_enum
          AS ENUM ('MARK_PAID', 'CANCEL');
      EXCEPTION WHEN duplicate_object THEN NULL; END $$
    `);

    await queryRunner.query(`
      DO $$ BEGIN
        CREATE TYPE freight.shipping_line_invoice_approvals_status_enum
          AS ENUM ('PENDING', 'APPROVED', 'REJECTED');
      EXCEPTION WHEN duplicate_object THEN NULL; END $$
    `);

    await queryRunner.query(`
      CREATE TABLE IF NOT EXISTS freight.shipping_line_invoice_approvals (
        id uuid PRIMARY KEY DEFAULT uuid_generate_v4(),
        invoice_id uuid NOT NULL REFERENCES freight.invoices (id),
        action freight.shipping_line_invoice_approvals_action_enum NOT NULL,
        status freight.shipping_line_invoice_approvals_status_enum NOT NULL DEFAULT 'PENDING',
        requested_by uuid NOT NULL,
        reason varchar(500) NOT NULL,
        payment_reference varchar(255),
        decided_by uuid,
        decided_at timestamptz,
        decision_note varchar(500),
        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_sl_invoice_approvals_invoice_status
        ON freight.shipping_line_invoice_approvals (invoice_id, status)
    `);

    // The workflow invariant, enforced where it cannot race: at most one
    // undecided request per invoice.
    await queryRunner.query(`
      CREATE UNIQUE INDEX IF NOT EXISTS uq_sl_invoice_approvals_one_pending
        ON freight.shipping_line_invoice_approvals (invoice_id)
        WHERE status = 'PENDING' AND deleted_at IS NULL
    `);
  }

  public async down(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.query(
      `DROP TABLE IF EXISTS freight.shipping_line_invoice_approvals`,
    );
    await queryRunner.query(
      `DROP TYPE IF EXISTS freight.shipping_line_invoice_approvals_status_enum`,
    );
    await queryRunner.query(
      `DROP TYPE IF EXISTS freight.shipping_line_invoice_approvals_action_enum`,
    );
  }
}