import { QueryInterface, DataTypes } from 'sequelize';

/**
 * Migration: Add skip-related fields to approval_levels table
 * Purpose: Track approvers who were skipped by initiator
 * Date: 2025-11-05
 */

export async function up(queryInterface: QueryInterface): Promise<void> {
  // Check if table exists first
  const tables = await queryInterface.showAllTables();
  if (!tables.includes('approval_levels')) {
    console.log('⚠️  approval_levels table does not exist yet, skipping...');
    return;
  }

  // Get existing columns
  const tableDescription = await queryInterface.describeTable('approval_levels');

  // Add skip-related columns only if they don't exist
  if (!tableDescription.is_skipped) {
    await queryInterface.addColumn('approval_levels', 'is_skipped', {
      type: DataTypes.BOOLEAN,
      allowNull: false,
      defaultValue: false,
      comment: 'Indicates if this approver was skipped by initiator'
    });
    console.log('  ✅ Added is_skipped column');
  }

  if (!tableDescription.skipped_at) {
    await queryInterface.addColumn('approval_levels', 'skipped_at', {
      type: DataTypes.DATE,
      allowNull: true,
      comment: 'Timestamp when approver was skipped'
    });
    console.log('  ✅ Added skipped_at column');
  }

  if (!tableDescription.skipped_by) {
    await queryInterface.addColumn('approval_levels', 'skipped_by', {
      type: DataTypes.UUID,
      allowNull: true,
      references: {
        model: 'users',
        key: 'user_id'
      },
      onUpdate: 'CASCADE',
      onDelete: 'SET NULL',
      comment: 'User ID who skipped this approver'
    });
    console.log('  ✅ Added skipped_by column');
  }

  if (!tableDescription.skip_reason) {
    await queryInterface.addColumn('approval_levels', 'skip_reason', {
      type: DataTypes.TEXT,
      allowNull: true,
      comment: 'Reason for skipping this approver'
    });
    console.log('  ✅ Added skip_reason column');
  }

  // Check if index exists before creating
  try {
    const indexes: any[] = await queryInterface.showIndex('approval_levels') as any[];
    const indexExists = Array.isArray(indexes) && indexes.some((idx: any) => idx.name === 'idx_approval_levels_skipped');
    
    if (!indexExists) {
      await queryInterface.addIndex('approval_levels', ['is_skipped'], {
        name: 'idx_approval_levels_skipped',
        where: {
          is_skipped: true
        }
      });
      console.log('  ✅ Added idx_approval_levels_skipped index');
    }
  } catch (error) {
    // Index might already exist, which is fine
    console.log('  ℹ️  Index already exists or could not be created');
  }

  console.log('✅ Skip-related fields migration completed');
}

export async function down(queryInterface: QueryInterface): Promise<void> {
  // Remove index first
  await queryInterface.removeIndex('approval_levels', 'idx_approval_levels_skipped');

  // Remove columns
  await queryInterface.removeColumn('approval_levels', 'skip_reason');
  await queryInterface.removeColumn('approval_levels', 'skipped_by');
  await queryInterface.removeColumn('approval_levels', 'skipped_at');
  await queryInterface.removeColumn('approval_levels', 'is_skipped');

  console.log('✅ Removed skip-related fields from approval_levels table');
}