import { MigrationInterface, QueryRunner } from 'typeorm';

function quoteIdentifier(identifier: string): string {
  return `"${identifier.replaceAll('"', '""')}"`;
}

export class PhaseD5325VerificationEventHistory1788890400000 implements MigrationInterface {
  name = 'PhaseD5325VerificationEventHistory1788890400000';

  public async up(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.query(`
      CREATE TABLE inspection_finding_verification_events (
        id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
        finding_id uuid NOT NULL,
        verification_visit_id uuid NULL,
        event_type varchar(40) NOT NULL,
        occurred_at timestamptz NOT NULL DEFAULT CURRENT_TIMESTAMP,
        target_control_on date NULL,
        previous_control_on date NULL,
        next_control_on date NULL,
        outcome varchar(24) NULL,
        notes text NULL,
        actor_user_id uuid NULL,
        actor_username varchar(80) NULL,
        created_at timestamptz NOT NULL DEFAULT CURRENT_TIMESTAMP,
        CONSTRAINT chk_inspection_finding_verification_event_type CHECK (
          event_type IN (
            'CONTROL_DATE_DEFINED', 'CONTROL_DATE_CHANGED', 'CONTROL_DATE_CLEARED',
            'VISIT_PLANNED', 'RESULT_RECORDED'
          )
        ),
        CONSTRAINT chk_inspection_finding_verification_event_outcome CHECK (
          outcome IS NULL OR outcome IN ('RESOLVED', 'NOT_RESOLVED', 'REQUIRES_NEW_DATE')
        ),
        CONSTRAINT fk_inspection_finding_verification_event_finding FOREIGN KEY (finding_id)
          REFERENCES inspection_findings(id) ON DELETE RESTRICT,
        CONSTRAINT fk_inspection_finding_verification_event_visit FOREIGN KEY (verification_visit_id)
          REFERENCES inspection_visits(id) ON DELETE RESTRICT,
        CONSTRAINT fk_inspection_finding_verification_event_actor FOREIGN KEY (actor_user_id)
          REFERENCES users(id) ON DELETE SET NULL
      )
    `);
    await queryRunner.query(`
      CREATE INDEX idx_inspection_finding_verification_events_finding
      ON inspection_finding_verification_events (finding_id, occurred_at DESC, created_at DESC)
    `);
    await queryRunner.query(`
      CREATE INDEX idx_inspection_finding_verification_events_visit
      ON inspection_finding_verification_events (verification_visit_id, occurred_at DESC)
    `);

    await queryRunner.query(`
      WITH ordered AS (
        SELECT
          version.finding_id,
          version.event,
          version.created_at,
          version.actor_user_id,
          version.actor_username,
          NULLIF(version.snapshot ->> 'nextControlOn', '')::date AS next_control_on,
          NULLIF(LAG(version.snapshot ->> 'nextControlOn') OVER (
            PARTITION BY version.finding_id ORDER BY version.version_number
          ), '')::date AS previous_control_on
        FROM inspection_finding_versions version
      )
      INSERT INTO inspection_finding_verification_events (
        finding_id, event_type, occurred_at, target_control_on,
        previous_control_on, next_control_on, notes, actor_user_id, actor_username
      )
      SELECT
        ordered.finding_id,
        CASE
          WHEN ordered.next_control_on IS NULL THEN 'CONTROL_DATE_CLEARED'
          WHEN ordered.previous_control_on IS NULL THEN 'CONTROL_DATE_DEFINED'
          ELSE 'CONTROL_DATE_CHANGED'
        END,
        ordered.created_at,
        ordered.next_control_on,
        ordered.previous_control_on,
        ordered.next_control_on,
        'Reconstruido desde historial versionado de seguimiento',
        ordered.actor_user_id,
        ordered.actor_username
      FROM ordered
      WHERE ordered.event = 'FOLLOW_UP_UPDATED'
        AND ordered.next_control_on IS DISTINCT FROM ordered.previous_control_on
    `);

    await queryRunner.query(`
      INSERT INTO inspection_finding_verification_events (
        finding_id, verification_visit_id, event_type, occurred_at,
        target_control_on, next_control_on, notes, actor_user_id
      )
      SELECT
        verification_link.finding_id,
        verification_link.visit_id,
        'VISIT_PLANNED',
        verification_link.created_at,
        verification_link.target_control_on,
        verification_link.target_control_on,
        'Visita de verificación reconstruida desde vínculo histórico',
        verification_link.linked_by
      FROM inspection_finding_verification_visits verification_link
    `);

    await queryRunner.query(`
      INSERT INTO inspection_finding_verification_events (
        finding_id, verification_visit_id, event_type, occurred_at,
        target_control_on, previous_control_on, next_control_on,
        outcome, notes, actor_user_id
      )
      SELECT
        verification_link.finding_id,
        verification_link.visit_id,
        'RESULT_RECORDED',
        COALESCE(verification_link.result_recorded_at, verification_link.verified_at, verification_link.updated_at),
        verification_link.target_control_on,
        verification_link.target_control_on,
        verification_link.rescheduled_control_on,
        verification_link.outcome,
        verification_link.result_notes,
        verification_link.result_recorded_by
      FROM inspection_finding_verification_visits verification_link
      WHERE verification_link.outcome IS NOT NULL
    `);

    await queryRunner.query(`
      INSERT INTO inspection_finding_verification_events (
        finding_id, verification_visit_id, event_type, occurred_at,
        target_control_on, previous_control_on, next_control_on,
        notes, actor_user_id
      )
      SELECT
        verification_link.finding_id,
        verification_link.visit_id,
        CASE WHEN verification_link.rescheduled_control_on IS NULL
          THEN 'CONTROL_DATE_CLEARED'
          ELSE 'CONTROL_DATE_CHANGED'
        END,
        COALESCE(verification_link.result_recorded_at, verification_link.verified_at, verification_link.updated_at),
        verification_link.rescheduled_control_on,
        verification_link.target_control_on,
        verification_link.rescheduled_control_on,
        CASE WHEN verification_link.rescheduled_control_on IS NULL
          THEN 'La verificación consumió la fecha prevista sin fijar un nuevo control'
          ELSE 'Nueva fecha definida como resultado de la verificación'
        END,
        verification_link.result_recorded_by
      FROM inspection_finding_verification_visits verification_link
      WHERE verification_link.outcome IS NOT NULL
    `);

    await queryRunner.query(`
      CREATE OR REPLACE FUNCTION protect_inspection_verification_result_immutability()
      RETURNS trigger AS $$
      BEGIN
        IF OLD.result_recorded_at IS NOT NULL AND (
          NEW.outcome IS DISTINCT FROM OLD.outcome
          OR NEW.result_notes IS DISTINCT FROM OLD.result_notes
          OR NEW.verified_at IS DISTINCT FROM OLD.verified_at
          OR NEW.result_recorded_at IS DISTINCT FROM OLD.result_recorded_at
          OR NEW.result_recorded_by IS DISTINCT FROM OLD.result_recorded_by
          OR NEW.rescheduled_control_on IS DISTINCT FROM OLD.rescheduled_control_on
        ) THEN
          RAISE EXCEPTION 'El resultado de verificación ya registrado es inmutable';
        END IF;
        RETURN NEW;
      END;
      $$ LANGUAGE plpgsql
    `);
    await queryRunner.query(`
      CREATE TRIGGER trg_inspection_verification_result_immutable
      BEFORE UPDATE ON inspection_finding_verification_visits
      FOR EACH ROW
      EXECUTE FUNCTION protect_inspection_verification_result_immutability()
    `);

    const appRole = process.env.DB_APP_USER;
    if (!appRole) throw new Error('Missing required environment variable: DB_APP_USER');
    const applicationRole = quoteIdentifier(appRole);
    await queryRunner.query(`GRANT SELECT, INSERT ON TABLE inspection_finding_verification_events TO ${applicationRole}`);
    await queryRunner.query(`REVOKE UPDATE, DELETE ON TABLE inspection_finding_verification_events FROM ${applicationRole}`);
  }

  public async down(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.query('DROP TRIGGER IF EXISTS trg_inspection_verification_result_immutable ON inspection_finding_verification_visits');
    await queryRunner.query('DROP FUNCTION IF EXISTS protect_inspection_verification_result_immutability()');
    await queryRunner.query('DROP TABLE inspection_finding_verification_events');
  }
}