const path = require('path');

// Change working directory to script directory
process.chdir(path.dirname(__filename));

require('dotenv').config({ path: path.resolve(__dirname, '..', '.env') });

// Configuration flags for controlling which metrics to calculate
// Set to 1 to skip the corresponding calculation, 0 to run it
const SKIP_PRODUCT_METRICS = 0;
const SKIP_TIME_AGGREGATES = 0;
const SKIP_FINANCIAL_METRICS = 0;
const SKIP_VENDOR_METRICS = 0;
const SKIP_CATEGORY_METRICS = 0;
const SKIP_BRAND_METRICS = 0;
const SKIP_SALES_FORECASTS = 0;

// Add error handler for uncaught exceptions
process.on('uncaughtException', (error) => {
    console.error('Uncaught Exception:', error);
    process.exit(1);
});

// Add error handler for unhandled promise rejections
process.on('unhandledRejection', (reason, promise) => {
    console.error('Unhandled Rejection at:', promise, 'reason:', reason);
    process.exit(1);
});

const progress = require('./metrics/utils/progress');
console.log('Progress module loaded:', {
    modulePath: require.resolve('./metrics/utils/progress'),
    exports: Object.keys(progress),
    currentDir: process.cwd(),
    scriptDir: __dirname
});

// Store progress functions in global scope to ensure availability
global.formatElapsedTime = progress.formatElapsedTime;
global.estimateRemaining = progress.estimateRemaining;
global.calculateRate = progress.calculateRate;
global.outputProgress = progress.outputProgress;
global.clearProgress = progress.clearProgress;
global.getProgress = progress.getProgress;
global.logError = progress.logError;

const { getConnection, closePool } = require('./metrics/utils/db');
const calculateProductMetrics = require('./metrics/product-metrics');
const calculateTimeAggregates = require('./metrics/time-aggregates');
const calculateFinancialMetrics = require('./metrics/financial-metrics');
const calculateVendorMetrics = require('./metrics/vendor-metrics');
const calculateCategoryMetrics = require('./metrics/category-metrics');
const calculateBrandMetrics = require('./metrics/brand-metrics');
const calculateSalesForecasts = require('./metrics/sales-forecasts');

// Add cancel handler
let isCancelled = false;

function cancelCalculation() {
    isCancelled = true;
    global.clearProgress();
    // Format as SSE event
    const event = {
        progress: {
            status: 'cancelled',
            operation: 'Calculation cancelled',
            current: 0,
            total: 0,
            elapsed: null,
            remaining: null,
            rate: 0,
            timestamp: Date.now()
        }
    };
    process.stdout.write(JSON.stringify(event) + '\n');
    process.exit(0);
}

// Handle SIGTERM signal for cancellation
process.on('SIGTERM', cancelCalculation);

// Update the main calculation function to use the new modular structure
async function calculateMetrics() {
    let connection;
    const startTime = Date.now();
    let processedCount = 0;
    let totalProducts = 0;
    
    try {
        // Add debug logging for the progress functions
        console.log('Debug - Progress functions:', {
            formatElapsedTime: typeof global.formatElapsedTime,
            estimateRemaining: typeof global.estimateRemaining,
            calculateRate: typeof global.calculateRate,
            startTime: startTime
        });

        try {
            const elapsed = global.formatElapsedTime(startTime);
            console.log('Debug - formatElapsedTime test successful:', elapsed);
        } catch (err) {
            console.error('Debug - Error testing formatElapsedTime:', err);
            throw err;
        }

        isCancelled = false;
        connection = await getConnection();

        try {
            global.outputProgress({
                status: 'running',
                operation: 'Starting metrics calculation',
                current: 0,
                total: 100,
                elapsed: '0s',
                remaining: 'Calculating...',
                rate: 0,
                percentage: '0',
                timing: {
                    start_time: new Date(startTime).toISOString(),
                    end_time: new Date().toISOString(),
                    elapsed_seconds: Math.round((Date.now() - startTime) / 1000)
                }
            });

            // Get total number of products
            const [countResult] = await connection.query('SELECT COUNT(*) as total FROM products')
                .catch(err => {
                    global.logError(err, 'Failed to count products');
                    throw err;
                });
            totalProducts = countResult[0].total;
            
            if (!SKIP_PRODUCT_METRICS) {
                processedCount = await calculateProductMetrics(startTime, totalProducts);
            } else {
                console.log('Skipping product metrics calculation...');
                processedCount = Math.floor(totalProducts * 0.6);
                global.outputProgress({
                    status: 'running',
                    operation: 'Skipping product metrics calculation',
                    current: processedCount,
                    total: totalProducts,
                    elapsed: global.formatElapsedTime(startTime),
                    remaining: global.estimateRemaining(startTime, processedCount, totalProducts),
                    rate: global.calculateRate(startTime, processedCount),
                    percentage: '60',
                    timing: {
                        start_time: new Date(startTime).toISOString(),
                        end_time: new Date().toISOString(),
                        elapsed_seconds: Math.round((Date.now() - startTime) / 1000)
                    }
                });
            }

            // Calculate time-based aggregates
            if (!SKIP_TIME_AGGREGATES) {
                processedCount = await calculateTimeAggregates(startTime, totalProducts, processedCount);
            } else {
                console.log('Skipping time aggregates calculation');
            }

            // Calculate financial metrics
            if (!SKIP_FINANCIAL_METRICS) {
                processedCount = await calculateFinancialMetrics(startTime, totalProducts, processedCount);
            } else {
                console.log('Skipping financial metrics calculation');
            }
            
            // Calculate vendor metrics
            if (!SKIP_VENDOR_METRICS) {
                processedCount = await calculateVendorMetrics(startTime, totalProducts, processedCount);
            } else {
                console.log('Skipping vendor metrics calculation');
            }

            // Calculate category metrics
            if (!SKIP_CATEGORY_METRICS) {
                processedCount = await calculateCategoryMetrics(startTime, totalProducts, processedCount);
            } else {
                console.log('Skipping category metrics calculation');
            }

            // Calculate brand metrics
            if (!SKIP_BRAND_METRICS) {
                processedCount = await calculateBrandMetrics(startTime, totalProducts, processedCount);
            } else {
                console.log('Skipping brand metrics calculation');
            }

            // Calculate sales forecasts
            if (!SKIP_SALES_FORECASTS) {
                processedCount = await calculateSalesForecasts(startTime, totalProducts, processedCount);
            } else {
                console.log('Skipping sales forecasts calculation');
            }

            // Calculate ABC classification
            outputProgress({
                status: 'running',
                operation: 'Starting ABC classification',
                current: processedCount,
                total: totalProducts,
                elapsed: formatElapsedTime(startTime),
                remaining: estimateRemaining(startTime, processedCount, totalProducts),
                rate: calculateRate(startTime, processedCount),
                percentage: ((processedCount / totalProducts) * 100).toFixed(1),
                timing: {
                    start_time: new Date(startTime).toISOString(),
                    end_time: new Date().toISOString(),
                    elapsed_seconds: Math.round((Date.now() - startTime) / 1000)
                }
            });

            if (isCancelled) return processedCount;

            const [abcConfig] = await connection.query('SELECT a_threshold, b_threshold FROM abc_classification_config WHERE id = 1');
            const abcThresholds = abcConfig[0] || { a_threshold: 20, b_threshold: 50 };

            // First, create and populate the rankings table with an index
            await connection.query('DROP TEMPORARY TABLE IF EXISTS temp_revenue_ranks');
            await connection.query(`
                CREATE TEMPORARY TABLE temp_revenue_ranks (
                    pid BIGINT NOT NULL,
                    total_revenue DECIMAL(10,3),
                    rank_num INT,
                    total_count INT,
                    PRIMARY KEY (pid),
                    INDEX (rank_num)
                ) ENGINE=MEMORY
            `);

            outputProgress({
                status: 'running',
                operation: 'Creating revenue rankings',
                current: processedCount,
                total: totalProducts,
                elapsed: formatElapsedTime(startTime),
                remaining: estimateRemaining(startTime, processedCount, totalProducts),
                rate: calculateRate(startTime, processedCount),
                percentage: ((processedCount / totalProducts) * 100).toFixed(1),
                timing: {
                    start_time: new Date(startTime).toISOString(),
                    end_time: new Date().toISOString(),
                    elapsed_seconds: Math.round((Date.now() - startTime) / 1000)
                }
            });

            if (isCancelled) return processedCount;

            await connection.query(`
                INSERT INTO temp_revenue_ranks
                SELECT 
                    pid,
                    total_revenue,
                    @rank := @rank + 1 as rank_num,
                    @total_count := @rank as total_count
                FROM (
                    SELECT pid, total_revenue 
                    FROM product_metrics 
                    WHERE total_revenue > 0 
                    ORDER BY total_revenue DESC
                ) ranked, 
                (SELECT @rank := 0) r
            `);

            // Get total count for percentage calculation
            const [rankingCount] = await connection.query('SELECT MAX(rank_num) as total_count FROM temp_revenue_ranks');
            const totalCount = rankingCount[0].total_count || 1;
            const max_rank = totalCount; // Store max_rank for use in classification

            outputProgress({
                status: 'running',
                operation: 'Updating ABC classifications',
                current: processedCount,
                total: totalProducts,
                elapsed: formatElapsedTime(startTime),
                remaining: estimateRemaining(startTime, processedCount, totalProducts),
                rate: calculateRate(startTime, processedCount),
                percentage: ((processedCount / totalProducts) * 100).toFixed(1),
                timing: {
                    start_time: new Date(startTime).toISOString(),
                    end_time: new Date().toISOString(),
                    elapsed_seconds: Math.round((Date.now() - startTime) / 1000)
                }
            });

            if (isCancelled) return processedCount;

            // Process updates in batches
            let abcProcessedCount = 0;
            const batchSize = 5000;

            while (true) {
                if (isCancelled) return processedCount;

                // First get a batch of PIDs that need updating
                const [pids] = await connection.query(`
                    SELECT pm.pid 
                    FROM product_metrics pm
                    LEFT JOIN temp_revenue_ranks tr ON pm.pid = tr.pid
                    WHERE pm.abc_class IS NULL 
                    OR pm.abc_class != 
                        CASE 
                            WHEN tr.rank_num IS NULL THEN 'C'
                            WHEN (tr.rank_num / ?) * 100 <= ? THEN 'A'
                            WHEN (tr.rank_num / ?) * 100 <= ? THEN 'B'
                            ELSE 'C'
                        END
                    LIMIT ?
                `, [max_rank, abcThresholds.a_threshold,
                    max_rank, abcThresholds.b_threshold,
                    batchSize]);

                if (pids.length === 0) {
                    break;
                }

                // Then update just those PIDs
                const [result] = await connection.query(`
                    UPDATE product_metrics pm
                    LEFT JOIN temp_revenue_ranks tr ON pm.pid = tr.pid
                    SET pm.abc_class = 
                        CASE 
                            WHEN tr.rank_num IS NULL THEN 'C'
                            WHEN (tr.rank_num / ?) * 100 <= ? THEN 'A'
                            WHEN (tr.rank_num / ?) * 100 <= ? THEN 'B'
                            ELSE 'C'
                        END,
                        pm.last_calculated_at = NOW()
                    WHERE pm.pid IN (?)
                `, [max_rank, abcThresholds.a_threshold,
                    max_rank, abcThresholds.b_threshold,
                    pids.map(row => row.pid)]);

                abcProcessedCount += result.affectedRows;
                processedCount = Math.floor(totalProducts * (0.99 + (abcProcessedCount / totalCount) * 0.01));

                outputProgress({
                    status: 'running',
                    operation: 'ABC classification progress',
                    current: processedCount,
                    total: totalProducts,
                    elapsed: formatElapsedTime(startTime),
                    remaining: estimateRemaining(startTime, processedCount, totalProducts),
                    rate: calculateRate(startTime, processedCount),
                    percentage: ((processedCount / totalProducts) * 100).toFixed(1),
                    timing: {
                        start_time: new Date(startTime).toISOString(),
                        end_time: new Date().toISOString(),
                        elapsed_seconds: Math.round((Date.now() - startTime) / 1000)
                    }
                });

                // Small delay between batches to allow other transactions
                await new Promise(resolve => setTimeout(resolve, 100));
            }

            // Clean up
            await connection.query('DROP TEMPORARY TABLE IF EXISTS temp_revenue_ranks');

            // Final success message
            outputProgress({
                status: 'complete',
                operation: 'Metrics calculation complete',
                current: totalProducts,
                total: totalProducts,
                elapsed: formatElapsedTime(startTime),
                remaining: '0s',
                rate: calculateRate(startTime, totalProducts),
                percentage: '100',
                timing: {
                    start_time: new Date(startTime).toISOString(),
                    end_time: new Date().toISOString(),
                    elapsed_seconds: Math.round((Date.now() - startTime) / 1000)
                }
            });

            // Clear progress file on successful completion
            global.clearProgress();

        } catch (error) {
            if (isCancelled) {
                global.outputProgress({
                    status: 'cancelled',
                    operation: 'Calculation cancelled',
                    current: processedCount,
                    total: totalProducts || 0,
                    elapsed: global.formatElapsedTime(startTime),
                    remaining: null,
                    rate: global.calculateRate(startTime, processedCount),
                    percentage: ((processedCount / (totalProducts || 1)) * 100).toFixed(1),
                    timing: {
                        start_time: new Date(startTime).toISOString(),
                        end_time: new Date().toISOString(),
                        elapsed_seconds: Math.round((Date.now() - startTime) / 1000)
                    }
                });
            } else {
                global.outputProgress({
                    status: 'error',
                    operation: 'Error: ' + error.message,
                    current: processedCount,
                    total: totalProducts || 0,
                    elapsed: global.formatElapsedTime(startTime),
                    remaining: null,
                    rate: global.calculateRate(startTime, processedCount),
                    percentage: ((processedCount / (totalProducts || 1)) * 100).toFixed(1),
                    timing: {
                        start_time: new Date(startTime).toISOString(),
                        end_time: new Date().toISOString(),
                        elapsed_seconds: Math.round((Date.now() - startTime) / 1000)
                    }
                });
            }
            throw error;
        } finally {
            if (connection) {
            connection.release();
            }
        }
    } finally {
        // Close the connection pool when we're done
        await closePool();
    }
}

// Export both functions and progress checker
module.exports = calculateMetrics;
module.exports.cancelCalculation = cancelCalculation;
module.exports.getProgress = global.getProgress;

// Run directly if called from command line
if (require.main === module) {
    calculateMetrics().catch(error => {
        if (!error.message.includes('Operation cancelled')) {
            console.error('Error:', error);
        }
        process.exit(1);
    });
}