import { QueryInterface, DataTypes } from 'sequelize';

export async function up(queryInterface: QueryInterface): Promise<void> {
  // Create claim_budget_tracking table for comprehensive budget management
  await queryInterface.createTable('claim_budget_tracking', {
    budget_id: {
      type: DataTypes.UUID,
      primaryKey: true,
      defaultValue: DataTypes.UUIDV4
    },
    request_id: {
      type: DataTypes.UUID,
      allowNull: false,
      unique: true,
      references: {
        model: 'workflow_requests',
        key: 'request_id'
      },
      onDelete: 'CASCADE',
      onUpdate: 'CASCADE'
    },
    // Initial Budget (from claim creation)
    initial_estimated_budget: {
      type: DataTypes.DECIMAL(15, 2),
      allowNull: true,
      comment: 'Initial estimated budget when claim was created'
    },
    // Proposal Budget (from Step 1 - Dealer Proposal)
    proposal_estimated_budget: {
      type: DataTypes.DECIMAL(15, 2),
      allowNull: true,
      comment: 'Total estimated budget from dealer proposal'
    },
    proposal_submitted_at: {
      type: DataTypes.DATE,
      allowNull: true,
      comment: 'When dealer submitted proposal'
    },
    // Approved Budget (from Step 2 - Requestor Evaluation)
    approved_budget: {
      type: DataTypes.DECIMAL(15, 2),
      allowNull: true,
      comment: 'Budget approved by requestor in Step 2'
    },
    approved_at: {
      type: DataTypes.DATE,
      allowNull: true,
      comment: 'When budget was approved by requestor'
    },
    approved_by: {
      type: DataTypes.UUID,
      allowNull: true,
      references: {
        model: 'users',
        key: 'user_id'
      },
      onDelete: 'SET NULL',
      onUpdate: 'CASCADE',
      comment: 'User who approved the budget'
    },
    // IO Blocked Budget (from Step 3 - Department Lead)
    io_blocked_amount: {
      type: DataTypes.DECIMAL(15, 2),
      allowNull: true,
      comment: 'Amount blocked in IO (from internal_orders table)'
    },
    io_blocked_at: {
      type: DataTypes.DATE,
      allowNull: true,
      comment: 'When budget was blocked in IO'
    },
    // Closed Expenses (from Step 5 - Dealer Completion)
    closed_expenses: {
      type: DataTypes.DECIMAL(15, 2),
      allowNull: true,
      comment: 'Total closed expenses from completion documents'
    },
    closed_expenses_submitted_at: {
      type: DataTypes.DATE,
      allowNull: true,
      comment: 'When completion expenses were submitted'
    },
    // Final Claim Amount (from Step 6 - Requestor Claim Approval)
    final_claim_amount: {
      type: DataTypes.DECIMAL(15, 2),
      allowNull: true,
      comment: 'Final claim amount approved/modified by requestor in Step 6'
    },
    final_claim_amount_approved_at: {
      type: DataTypes.DATE,
      allowNull: true,
      comment: 'When final claim amount was approved'
    },
    final_claim_amount_approved_by: {
      type: DataTypes.UUID,
      allowNull: true,
      references: {
        model: 'users',
        key: 'user_id'
      },
      onDelete: 'SET NULL',
      onUpdate: 'CASCADE',
      comment: 'User who approved final claim amount'
    },
    // Credit Note (from Step 8 - Finance)
    credit_note_amount: {
      type: DataTypes.DECIMAL(15, 2),
      allowNull: true,
      comment: 'Credit note amount issued by finance'
    },
    credit_note_issued_at: {
      type: DataTypes.DATE,
      allowNull: true,
      comment: 'When credit note was issued'
    },
    // Budget Status
    budget_status: {
      type: DataTypes.ENUM('DRAFT', 'PROPOSED', 'APPROVED', 'BLOCKED', 'CLOSED', 'SETTLED'),
      defaultValue: 'DRAFT',
      allowNull: false,
      comment: 'Current status of budget lifecycle'
    },
    // Currency
    currency: {
      type: DataTypes.STRING(3),
      defaultValue: 'INR',
      allowNull: false,
      comment: 'Currency code (INR, USD, etc.)'
    },
    // Budget Variance
    variance_amount: {
      type: DataTypes.DECIMAL(15, 2),
      allowNull: true,
      comment: 'Difference between approved and closed expenses (closed - approved)'
    },
    variance_percentage: {
      type: DataTypes.DECIMAL(5, 2),
      allowNull: true,
      comment: 'Variance as percentage of approved budget'
    },
    // Audit fields
    last_modified_by: {
      type: DataTypes.UUID,
      allowNull: true,
      references: {
        model: 'users',
        key: 'user_id'
      },
      onDelete: 'SET NULL',
      onUpdate: 'CASCADE',
      comment: 'Last user who modified budget'
    },
    last_modified_at: {
      type: DataTypes.DATE,
      allowNull: true,
      comment: 'When budget was last modified'
    },
    modification_reason: {
      type: DataTypes.TEXT,
      allowNull: true,
      comment: 'Reason for budget modification'
    },
    created_at: {
      type: DataTypes.DATE,
      allowNull: false,
      defaultValue: DataTypes.NOW
    },
    updated_at: {
      type: DataTypes.DATE,
      allowNull: false,
      defaultValue: DataTypes.NOW
    }
  });

  // Create indexes
  await queryInterface.addIndex('claim_budget_tracking', ['request_id'], {
    name: 'idx_claim_budget_tracking_request_id',
    unique: true
  });

  await queryInterface.addIndex('claim_budget_tracking', ['budget_status'], {
    name: 'idx_claim_budget_tracking_status'
  });

  await queryInterface.addIndex('claim_budget_tracking', ['approved_by'], {
    name: 'idx_claim_budget_tracking_approved_by'
  });

  await queryInterface.addIndex('claim_budget_tracking', ['final_claim_amount_approved_by'], {
    name: 'idx_claim_budget_tracking_final_approved_by'
  });
}

export async function down(queryInterface: QueryInterface): Promise<void> {
  await queryInterface.dropTable('claim_budget_tracking');
}