import { QueryInterface, DataTypes } from 'sequelize';

/**
 * Migration to create TAT alerts/reminders table
 * Stores all TAT-related notifications sent (50%, 75%, 100%)
 */
export async function up(queryInterface: QueryInterface): Promise<void> {
  await queryInterface.createTable('tat_alerts', {
    alert_id: {
      type: DataTypes.UUID,
      defaultValue: DataTypes.UUIDV4,
      primaryKey: true
    },
    request_id: {
      type: DataTypes.UUID,
      allowNull: false,
      references: {
        model: 'workflow_requests',
        key: 'request_id'
      }
    },
    level_id: {
      type: DataTypes.UUID,
      allowNull: false,
      references: {
        model: 'approval_levels',
        key: 'level_id'
      }
    },
    approver_id: {
      type: DataTypes.UUID,
      allowNull: false,
      references: {
        model: 'users',
        key: 'user_id'
      }
    },
    alert_type: {
      type: DataTypes.ENUM('TAT_50', 'TAT_75', 'TAT_100'),
      allowNull: false
    },
    threshold_percentage: {
      type: DataTypes.INTEGER,
      allowNull: false,
      comment: '50, 75, or 100'
    },
    tat_hours_allocated: {
      type: DataTypes.DECIMAL(10, 2),
      allowNull: false,
      comment: 'Total TAT hours for this level'
    },
    tat_hours_elapsed: {
      type: DataTypes.DECIMAL(10, 2),
      allowNull: false,
      comment: 'Hours elapsed when alert was sent'
    },
    tat_hours_remaining: {
      type: DataTypes.DECIMAL(10, 2),
      allowNull: false,
      comment: 'Hours remaining when alert was sent'
    },
    level_start_time: {
      type: DataTypes.DATE,
      allowNull: false,
      comment: 'When the approval level started'
    },
    alert_sent_at: {
      type: DataTypes.DATE,
      allowNull: false,
      defaultValue: DataTypes.NOW,
      comment: 'When the alert was sent'
    },
    expected_completion_time: {
      type: DataTypes.DATE,
      allowNull: false,
      comment: 'When the level should be completed'
    },
    alert_message: {
      type: DataTypes.TEXT,
      allowNull: false,
      comment: 'The notification message sent'
    },
    notification_sent: {
      type: DataTypes.BOOLEAN,
      defaultValue: true,
      comment: 'Whether notification was successfully sent'
    },
    notification_channels: {
      type: DataTypes.ARRAY(DataTypes.STRING),
      defaultValue: [],
      comment: 'push, email, sms'
    },
    is_breached: {
      type: DataTypes.BOOLEAN,
      defaultValue: false,
      comment: 'Whether this was a breach alert (100%)'
    },
    was_completed_on_time: {
      type: DataTypes.BOOLEAN,
      allowNull: true,
      comment: 'Set when level is completed - was it on time?'
    },
    completion_time: {
      type: DataTypes.DATE,
      allowNull: true,
      comment: 'When the level was actually completed'
    },
    metadata: {
      type: DataTypes.JSONB,
      defaultValue: {},
      comment: 'Additional context (priority, request title, etc.)'
    },
    created_at: {
      type: DataTypes.DATE,
      allowNull: false,
      defaultValue: DataTypes.NOW
    }
  });

  // Indexes for performance (with IF NOT EXISTS check)
  await queryInterface.sequelize.query('CREATE INDEX IF NOT EXISTS "tat_alerts_request_id" ON "tat_alerts" ("request_id");');
  await queryInterface.sequelize.query('CREATE INDEX IF NOT EXISTS "tat_alerts_level_id" ON "tat_alerts" ("level_id");');
  await queryInterface.sequelize.query('CREATE INDEX IF NOT EXISTS "tat_alerts_approver_id" ON "tat_alerts" ("approver_id");');
  await queryInterface.sequelize.query('CREATE INDEX IF NOT EXISTS "tat_alerts_alert_type" ON "tat_alerts" ("alert_type");');
  await queryInterface.sequelize.query('CREATE INDEX IF NOT EXISTS "tat_alerts_alert_sent_at" ON "tat_alerts" ("alert_sent_at");');
  await queryInterface.sequelize.query('CREATE INDEX IF NOT EXISTS "tat_alerts_is_breached" ON "tat_alerts" ("is_breached");');
  await queryInterface.sequelize.query('CREATE INDEX IF NOT EXISTS "tat_alerts_was_completed_on_time" ON "tat_alerts" ("was_completed_on_time");');
}

export async function down(queryInterface: QueryInterface): Promise<void> {
  await queryInterface.dropTable('tat_alerts');
  await queryInterface.sequelize.query('DROP TYPE IF EXISTS "enum_tat_alerts_alert_type";');
}