// node_api/jobs/depreciationDatabase.js
const { Pool } = require('pg');
const { logger } = require('../utils/logger');

class DepreciationDatabase {
  constructor() {
    this.pool = new Pool({
      host: process.env.DB_HOST || 'localhost',
      port: process.env.DB_PORT || 5432,
      database: process.env.DB_DATABASE || 'directus',
      user: process.env.DB_USERNAME || 'directus',
      password: process.env.DB_PASSWORD || 'directus',
      max: 10,
      idleTimeoutMillis: 30000,
      connectionTimeoutMillis: 2000,
    });
  }

  /**
   * Get all assets eligible for depreciation
   */
  async getAssetsForDepreciation(calculationDate = new Date()) {
    const client = await this.pool.connect();
    
    try {
      const query = `
        SELECT 
          a.id,
          a.name,
          a.acquisition_cost,
          a.acquisition_date,
          a.depreciation_method,
          a.depreciation_percentage_rate,
          a.expected_useful_life_months,
          a.salvage_value,
          a.total_accumulated_depreciation,
          a.net_book_value,
          a.status,
          a.expected_total_units,
          a.current_month_units,
          a.organization_id,
          a.date_created,
          a.date_updated
        FROM assets a
        WHERE 
          a.status = 'active'
          AND a.acquisition_cost > 0
          AND a.acquisition_date IS NOT NULL
          AND a.acquisition_date <= $1
          AND a.depreciation_method IS NOT NULL
          AND (
            a.total_accumulated_depreciation IS NULL 
            OR a.total_accumulated_depreciation < (a.acquisition_cost - COALESCE(a.salvage_value, 0))
          )
        ORDER BY a.acquisition_date ASC
      `;

      const result = await client.query(query, [calculationDate]);
      
      logger.depreciation(`Found ${result.rows.length} assets eligible for depreciation`, {
        calculationDate,
        assetCount: result.rows.length
      });

      return result.rows;
    } catch (error) {
      logger.error('Error fetching assets for depreciation:', error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Get the last depreciation record for an asset
   */
  async getLastDepreciationRecord(assetId) {
    const client = await this.pool.connect();
    
    try {
      const query = `
        SELECT *
        FROM asset_depreciation_records
        WHERE asset_id = $1
        ORDER BY depreciation_date DESC
        LIMIT 1
      `;

      const result = await client.query(query, [assetId]);
      return result.rows[0] || null;
    } catch (error) {
      logger.error(`Error fetching last depreciation record for asset ${assetId}:`, error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Check if depreciation record exists for asset and date
   */
  async depreciationRecordExists(assetId, depreciationDate) {
    const client = await this.pool.connect();
    
    try {
      const query = `
        SELECT COUNT(*) as count
        FROM asset_depreciation_records
        WHERE asset_id = $1 
        AND DATE_TRUNC('month', depreciation_date) = DATE_TRUNC('month', $2)
      `;

      const result = await client.query(query, [assetId, depreciationDate]);
      return parseInt(result.rows[0].count) > 0;
    } catch (error) {
      logger.error(`Error checking depreciation record existence:`, error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Create a new depreciation record
   */
  async createDepreciationRecord(depreciationData) {
    const client = await this.pool.connect();
    
    try {
      await client.query('BEGIN');

      const {
        asset_id,
        depreciation_date,
        depreciation_method,
        monthly_depreciation,
        accumulated_depreciation_before,
        accumulated_depreciation_after,
        net_book_value_before,
        net_book_value_after,
        calculation_details
      } = depreciationData;

      // Insert depreciation record
      const insertQuery = `
        INSERT INTO asset_depreciation_records (
          id,
          asset_id,
          depreciation_date,
          depreciation_method,
          monthly_depreciation,
          accumulated_depreciation_before,
          accumulated_depreciation_after,
          net_book_value_before,
          net_book_value_after,
          calculation_details,
          date_created,
          date_updated
        ) VALUES (
          gen_random_uuid(),
          $1, $2, $3, $4, $5, $6, $7, $8, $9, NOW(), NOW()
        )
        RETURNING id
      `;

      const insertResult = await client.query(insertQuery, [
        asset_id,
        depreciation_date,
        depreciation_method,
        monthly_depreciation,
        accumulated_depreciation_before,
        accumulated_depreciation_after,
        net_book_value_before,
        net_book_value_after,
        JSON.stringify(calculation_details)
      ]);

      // Update asset's accumulated depreciation and net book value
      const updateAssetQuery = `
        UPDATE assets 
        SET 
          total_accumulated_depreciation = $1,
          net_book_value = $2,
          date_updated = NOW()
        WHERE id = $3
      `;

      await client.query(updateAssetQuery, [
        accumulated_depreciation_after,
        net_book_value_after,
        asset_id
      ]);

      await client.query('COMMIT');

      logger.depreciation(`Created depreciation record for asset ${asset_id}`, {
        recordId: insertResult.rows[0].id,
        assetId: asset_id,
        monthlyDepreciation: monthly_depreciation,
        accumulatedDepreciation: accumulated_depreciation_after
      });

      return insertResult.rows[0].id;
    } catch (error) {
      await client.query('ROLLBACK');
      logger.error(`Error creating depreciation record:`, error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Get depreciation summary for a specific period
   */
  async getDepreciationSummary(startDate, endDate) {
    const client = await this.pool.connect();
    
    try {
      const query = `
        SELECT 
          COUNT(*) as total_assets,
          SUM(monthly_depreciation) as total_monthly_depreciation,
          AVG(monthly_depreciation) as avg_monthly_depreciation,
          MIN(monthly_depreciation) as min_monthly_depreciation,
          MAX(monthly_depreciation) as max_monthly_depreciation,
          depreciation_method,
          COUNT(*) as method_count
        FROM asset_depreciation_records
        WHERE depreciation_date BETWEEN $1 AND $2
        GROUP BY depreciation_method
        ORDER BY method_count DESC
      `;

      const result = await client.query(query, [startDate, endDate]);
      
      const overallQuery = `
        SELECT 
          COUNT(*) as total_assets,
          SUM(monthly_depreciation) as total_monthly_depreciation,
          AVG(monthly_depreciation) as avg_monthly_depreciation
        FROM asset_depreciation_records
        WHERE depreciation_date BETWEEN $1 AND $2
      `;

      const overallResult = await client.query(overallQuery, [startDate, endDate]);

      return {
        overall: overallResult.rows[0],
        byMethod: result.rows
      };
    } catch (error) {
      logger.error('Error getting depreciation summary:', error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Get assets with depreciation issues
   */
  async getDepreciationIssues() {
    const client = await this.pool.connect();
    
    try {
      const query = `
        SELECT 
          a.id,
          a.name,
          a.acquisition_cost,
          a.total_accumulated_depreciation,
          a.net_book_value,
          a.depreciation_method,
          CASE 
            WHEN a.total_accumulated_depreciation > a.acquisition_cost THEN 'over_depreciated'
            WHEN a.net_book_value < 0 THEN 'negative_book_value'
            WHEN a.net_book_value != (a.acquisition_cost - COALESCE(a.total_accumulated_depreciation, 0)) THEN 'calculation_mismatch'
            ELSE 'unknown'
          END as issue_type
        FROM assets a
        WHERE 
          a.status = 'active'
          AND (
            a.total_accumulated_depreciation > a.acquisition_cost
            OR a.net_book_value < 0
            OR a.net_book_value != (a.acquisition_cost - COALESCE(a.total_accumulated_depreciation, 0))
          )
        ORDER BY a.name
      `;

      const result = await client.query(query);
      return result.rows;
    } catch (error) {
      logger.error('Error getting depreciation issues:', error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Fix calculation mismatches
   */
  async fixCalculationMismatches() {
    const client = await this.pool.connect();
    
    try {
      await client.query('BEGIN');

      const updateQuery = `
        UPDATE assets 
        SET 
          net_book_value = acquisition_cost - COALESCE(total_accumulated_depreciation, 0),
          date_updated = NOW()
        WHERE 
          status = 'active'
          AND net_book_value != (acquisition_cost - COALESCE(total_accumulated_depreciation, 0))
      `;

      const result = await client.query(updateQuery);
      
      await client.query('COMMIT');

      logger.depreciation(`Fixed calculation mismatches for ${result.rowCount} assets`);
      
      return result.rowCount;
    } catch (error) {
      await client.query('ROLLBACK');
      logger.error('Error fixing calculation mismatches:', error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Get monthly depreciation report
   */
  async getMonthlyDepreciationReport(year, month) {
    const client = await this.pool.connect();
    
    try {
      const query = `
        SELECT 
          a.id,
          a.name,
          a.acquisition_cost,
          dr.monthly_depreciation,
          dr.accumulated_depreciation_before,
          dr.accumulated_depreciation_after,
          dr.net_book_value_before,
          dr.net_book_value_after,
          dr.depreciation_method,
          dr.depreciation_date,
          c.name as category_name,
          l.name as location_name
        FROM asset_depreciation_records dr
        JOIN assets a ON dr.asset_id = a.id
        LEFT JOIN categories c ON a.category_id = c.id
        LEFT JOIN locations l ON a.location_id = l.id
        WHERE 
          EXTRACT(YEAR FROM dr.depreciation_date) = $1
          AND EXTRACT(MONTH FROM dr.depreciation_date) = $2
        ORDER BY dr.monthly_depreciation DESC
      `;

      const result = await client.query(query, [year, month]);
      return result.rows;
    } catch (error) {
      logger.error('Error getting monthly depreciation report:', error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Get all asset components eligible for depreciation
   */
  async getAssetComponentsForDepreciation(calculationDate = new Date()) {
    const client = await this.pool.connect();
    
    try {
      const query = `
        SELECT 
          ac.id,
          ac.name,
          ac.component_identifier,
          ac.parent_asset_id,
          ac.acquisition_cost,
          ac.acquisition_date,
          ac.depreciation_method,
          ac.depreciation_percentage_rate,
          ac.expected_useful_life_months,
          ac.salvage_value,
          ac.total_accumulated_depreciation,
          ac.net_book_value,
          ac.status,
          ac.expected_total_units,
          ac.current_month_units,
          ac.organization_id,
          ac.date_created,
          ac.date_updated,
          a.name as parent_asset_name,
          a.asset_identifier as parent_asset_identifier
        FROM asset_components ac
        JOIN assets a ON ac.parent_asset_id = a.id
        WHERE 
          ac.status = 'active'
          AND ac.acquisition_cost > 0
          AND ac.acquisition_date IS NOT NULL
          AND ac.acquisition_date <= $1
          AND ac.depreciation_method IS NOT NULL
          AND (
            ac.total_accumulated_depreciation IS NULL 
            OR ac.total_accumulated_depreciation < (ac.acquisition_cost - COALESCE(ac.salvage_value, 0))
          )
        ORDER BY ac.acquisition_date ASC
      `;

      const result = await client.query(query, [calculationDate]);
      
      logger.depreciation(`Found ${result.rows.length} asset components eligible for depreciation`, {
        calculationDate,
        componentCount: result.rows.length
      });

      return result.rows;
    } catch (error) {
      logger.error('Error fetching asset components for depreciation:', error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Get the last depreciation record for an asset component
   */
  async getLastComponentDepreciationRecord(componentId) {
    const client = await this.pool.connect();
    
    try {
      const query = `
        SELECT *
        FROM asset_component_depreciation_records
        WHERE component_id = $1
        ORDER BY depreciation_date DESC
        LIMIT 1
      `;

      const result = await client.query(query, [componentId]);
      return result.rows[0] || null;
    } catch (error) {
      logger.error(`Error fetching last depreciation record for component ${componentId}:`, error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Check if depreciation record exists for component and date
   */
  async componentDepreciationRecordExists(componentId, depreciationDate) {
    const client = await this.pool.connect();
    
    try {
      const query = `
        SELECT COUNT(*) as count
        FROM asset_component_depreciation_records
        WHERE component_id = $1 
        AND DATE_TRUNC('month', depreciation_date) = DATE_TRUNC('month', $2)
      `;

      const result = await client.query(query, [componentId, depreciationDate]);
      return parseInt(result.rows[0].count) > 0;
    } catch (error) {
      logger.error(`Error checking component depreciation record existence:`, error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Create a new asset component depreciation record
   */
  async createComponentDepreciationRecord(depreciationData) {
    const client = await this.pool.connect();
    
    try {
      await client.query('BEGIN');

      const {
        component_id,
        asset_id,
        depreciation_date,
        depreciation_method,
        monthly_depreciation,
        accumulated_depreciation_before,
        accumulated_depreciation_after,
        net_book_value_before,
        net_book_value_after,
        calculation_details
      } = depreciationData;

      // Insert component depreciation record
      const insertQuery = `
        INSERT INTO asset_component_depreciation_records (
          id,
          component_id,
          asset_id,
          depreciation_date,
          depreciation_method,
          monthly_depreciation,
          accumulated_depreciation_before,
          accumulated_depreciation_after,
          net_book_value_before,
          net_book_value_after,
          calculation_details,
          date_created,
          date_updated
        ) VALUES (
          gen_random_uuid(),
          $1, $2, $3, $4, $5, $6, $7, $8, $9, $10, NOW(), NOW()
        )
        RETURNING id
      `;

      const insertResult = await client.query(insertQuery, [
        component_id,
        asset_id,
        depreciation_date,
        depreciation_method,
        monthly_depreciation,
        accumulated_depreciation_before,
        accumulated_depreciation_after,
        net_book_value_before,
        net_book_value_after,
        JSON.stringify(calculation_details)
      ]);

      // Update component's accumulated depreciation and net book value
      const updateComponentQuery = `
        UPDATE asset_components 
        SET 
          total_accumulated_depreciation = $1,
          net_book_value = $2,
          date_updated = NOW()
        WHERE id = $3
      `;

      await client.query(updateComponentQuery, [
        accumulated_depreciation_after,
        net_book_value_after,
        component_id
      ]);

      await client.query('COMMIT');

      logger.depreciation(`Created component depreciation record for component ${component_id}`, {
        recordId: insertResult.rows[0].id,
        componentId: component_id,
        assetId: asset_id,
        monthlyDepreciation: monthly_depreciation,
        accumulatedDepreciation: accumulated_depreciation_after
      });

      return insertResult.rows[0].id;
    } catch (error) {
      await client.query('ROLLBACK');
      logger.error(`Error creating component depreciation record:`, error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Get asset components with depreciation issues
   */
  async getComponentDepreciationIssues() {
    const client = await this.pool.connect();
    
    try {
      const query = `
        SELECT 
          ac.id,
          ac.name,
          ac.component_identifier,
          ac.parent_asset_id,
          a.name as parent_asset_name,
          a.asset_identifier as parent_asset_identifier,
          ac.acquisition_cost,
          ac.total_accumulated_depreciation,
          ac.net_book_value,
          ac.depreciation_method,
          CASE 
            WHEN ac.total_accumulated_depreciation > ac.acquisition_cost THEN 'over_depreciated'
            WHEN ac.net_book_value < 0 THEN 'negative_book_value'
            WHEN ac.net_book_value != (ac.acquisition_cost - COALESCE(ac.total_accumulated_depreciation, 0)) THEN 'calculation_mismatch'
            ELSE 'unknown'
          END as issue_type
        FROM asset_components ac
        JOIN assets a ON ac.parent_asset_id = a.id
        WHERE 
          ac.status = 'active'
          AND (
            ac.total_accumulated_depreciation > ac.acquisition_cost
            OR ac.net_book_value < 0
            OR ac.net_book_value != (ac.acquisition_cost - COALESCE(ac.total_accumulated_depreciation, 0))
          )
        ORDER BY ac.name
      `;

      const result = await client.query(query);
      return result.rows;
    } catch (error) {
      logger.error('Error getting component depreciation issues:', error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Fix component calculation mismatches
   */
  async fixComponentCalculationMismatches() {
    const client = await this.pool.connect();
    
    try {
      await client.query('BEGIN');

      const updateQuery = `
        UPDATE asset_components 
        SET 
          net_book_value = acquisition_cost - COALESCE(total_accumulated_depreciation, 0),
          date_updated = NOW()
        WHERE 
          status = 'active'
          AND net_book_value != (acquisition_cost - COALESCE(total_accumulated_depreciation, 0))
      `;

      const result = await client.query(updateQuery);
      
      await client.query('COMMIT');

      logger.depreciation(`Fixed component calculation mismatches for ${result.rowCount} components`);
      
      return result.rowCount;
    } catch (error) {
      await client.query('ROLLBACK');
      logger.error('Error fixing component calculation mismatches:', error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Get monthly component depreciation report
   */
  async getMonthlyComponentDepreciationReport(year, month) {
    const client = await this.pool.connect();
    
    try {
      const query = `
        SELECT 
          ac.id,
          ac.name,
          ac.component_identifier,
          ac.parent_asset_id,
          a.name as parent_asset_name,
          a.asset_identifier as parent_asset_identifier,
          ac.acquisition_cost,
          dr.monthly_depreciation,
          dr.accumulated_depreciation_before,
          dr.accumulated_depreciation_after,
          dr.net_book_value_before,
          dr.net_book_value_after,
          dr.depreciation_method,
          dr.depreciation_date,
          c.name as category_name,
          l.name as location_name
        FROM asset_component_depreciation_records dr
        JOIN asset_components ac ON dr.component_id = ac.id
        JOIN assets a ON dr.asset_id = a.id
        LEFT JOIN asset_categories c ON a.category_id = c.id
        LEFT JOIN locations l ON a.location_id = l.id
        WHERE 
          EXTRACT(YEAR FROM dr.depreciation_date) = $1
          AND EXTRACT(MONTH FROM dr.depreciation_date) = $2
        ORDER BY dr.monthly_depreciation DESC
      `;

      const result = await client.query(query, [year, month]);
      return result.rows;
    } catch (error) {
      logger.error('Error getting monthly component depreciation report:', error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Get component depreciation summary for a period
   */
  async getComponentDepreciationSummary(startDate, endDate) {
    const client = await this.pool.connect();
    
    try {
      const query = `
        SELECT 
          COUNT(*) as total_components,
          SUM(monthly_depreciation) as total_monthly_depreciation,
          AVG(monthly_depreciation) as avg_monthly_depreciation,
          MIN(monthly_depreciation) as min_monthly_depreciation,
          MAX(monthly_depreciation) as max_monthly_depreciation,
          depreciation_method,
          COUNT(*) as method_count
        FROM asset_component_depreciation_records
        WHERE depreciation_date BETWEEN $1 AND $2
        GROUP BY depreciation_method
        ORDER BY method_count DESC
      `;

      const result = await client.query(query, [startDate, endDate]);
      
      const overallQuery = `
        SELECT 
          COUNT(*) as total_components,
          SUM(monthly_depreciation) as total_monthly_depreciation,
          AVG(monthly_depreciation) as avg_monthly_depreciation
        FROM asset_component_depreciation_records
        WHERE depreciation_date BETWEEN $1 AND $2
      `;

      const overallResult = await client.query(overallQuery, [startDate, endDate]);

      return {
        overall: overallResult.rows[0],
        byMethod: result.rows
      };
    } catch (error) {
      logger.error('Error getting component depreciation summary:', error);
      throw error;
    } finally {
      client.release();
    }
  }

  /**
   * Close database connection pool
   */
  async close() {
    await this.pool.end();
    logger.info('Database connection pool closed');
  }
}

module.exports = { DepreciationDatabase };