// Package logging provides request logging functionality for the CLI Proxy API server.
// This file contains metrics integration for the FileStreamingLogWriter.
package logging

import (
	"os"
	"path/filepath"
	"sync/atomic"
	"time"

	"github.com/router-for-me/CLIProxyAPI/v6/internal/domain/ports"
)

// MetricsEnabledFileStreamingLogWriter wraps FileStreamingLogWriter with metrics collection
type MetricsEnabledFileStreamingLogWriter struct {
	*FileStreamingLogWriter
	metrics      ports.MetricsService
	dropCount    atomic.Uint64
	startTime    time.Time
	bytesWritten atomic.Int64
}

// NewMetricsEnabledFileStreamingLogWriter creates a new metrics-enabled streaming log writer
func NewMetricsEnabledFileStreamingLogWriter(
	base *FileStreamingLogWriter,
	metrics ports.MetricsService,
) *MetricsEnabledFileStreamingLogWriter {
	if metrics == nil {
		metrics = &ports.NoOpMetricsService{}
	}

	writer := &MetricsEnabledFileStreamingLogWriter{
		FileStreamingLogWriter: base,
		metrics:                metrics,
		startTime:              time.Now(),
	}

	// Report initial queue depth
	if base != nil && base.chunkChan != nil {
		metrics.RecordLogQueueDepth(len(base.chunkChan))
	}

	return writer
}

// WriteChunkAsync writes a response chunk asynchronously with metrics tracking
func (w *MetricsEnabledFileStreamingLogWriter) WriteChunkAsync(chunk []byte) {
	if w.FileStreamingLogWriter == nil {
		return
	}

	// Track queue depth before write
	if w.chunkChan != nil {
		w.metrics.RecordLogQueueDepth(len(w.chunkChan))
	}

	// Try to write to channel
	select {
	case w.chunkChan <- chunk:
		// Success - record bytes
		w.bytesWritten.Add(int64(len(chunk)))
	default:
		// Channel full - record drop
		w.dropCount.Add(1)
		w.metrics.RecordLogDropCount(1)
	}

	// Update queue depth after write
	if w.chunkChan != nil {
		w.metrics.RecordLogQueueDepth(len(w.chunkChan))
	}
}

// WriteStatus writes the response status with metrics tracking
func (w *MetricsEnabledFileStreamingLogWriter) WriteStatus(status int, headers map[string][]string) error {
	if w.FileStreamingLogWriter == nil {
		return nil
	}

	return w.FileStreamingLogWriter.WriteStatus(status, headers)
}

// WriteAPIRequest writes the API request with metrics tracking
func (w *MetricsEnabledFileStreamingLogWriter) WriteAPIRequest(apiRequest []byte) error {
	if w.FileStreamingLogWriter == nil {
		return nil
	}

	if len(apiRequest) > 0 {
		w.bytesWritten.Add(int64(len(apiRequest)))
	}

	return w.FileStreamingLogWriter.WriteAPIRequest(apiRequest)
}

// WriteAPIResponse writes the API response with metrics tracking
func (w *MetricsEnabledFileStreamingLogWriter) WriteAPIResponse(apiResponse []byte) error {
	if w.FileStreamingLogWriter == nil {
		return nil
	}

	if len(apiResponse) > 0 {
		w.bytesWritten.Add(int64(len(apiResponse)))
	}

	return w.FileStreamingLogWriter.WriteAPIResponse(apiResponse)
}

// Close finalizes the log and records final metrics
func (w *MetricsEnabledFileStreamingLogWriter) Close() error {
	if w.FileStreamingLogWriter == nil {
		return nil
	}

	// Record processing latency
	duration := time.Since(w.startTime)
	w.metrics.RecordLogProcessingLatency(duration)

	// Record total bytes written
	w.metrics.RecordLogWrite(w.bytesWritten.Load())

	// Record any drops
	drops := w.dropCount.Load()
	if drops > 0 {
		w.metrics.RecordLogDropCount(drops)
	}

	// Report final queue depth (should be 0 or close to it)
	if w.chunkChan != nil {
		w.metrics.RecordLogQueueDepth(len(w.chunkChan))
	}

	return w.FileStreamingLogWriter.Close()
}

// GetDropCount returns the number of dropped chunks
func (w *MetricsEnabledFileStreamingLogWriter) GetDropCount() uint64 {
	return w.dropCount.Load()
}

// GetBytesWritten returns the total bytes written
func (w *MetricsEnabledFileStreamingLogWriter) GetBytesWritten() int64 {
	return w.bytesWritten.Load()
}

// GetProcessingDuration returns the processing duration
func (w *MetricsEnabledFileStreamingLogWriter) GetProcessingDuration() time.Duration {
	return time.Since(w.startTime)
}

// FileRequestLoggerWithMetrics wraps FileRequestLogger with metrics support
type FileRequestLoggerWithMetrics struct {
	*FileRequestLogger
	metrics ports.MetricsService
}

// NewFileRequestLoggerWithMetrics creates a new FileRequestLogger with metrics support
func NewFileRequestLoggerWithMetrics(
	base *FileRequestLogger,
	metrics ports.MetricsService,
) *FileRequestLoggerWithMetrics {
	if metrics == nil {
		metrics = &ports.NoOpMetricsService{}
	}

	return &FileRequestLoggerWithMetrics{
		FileRequestLogger: base,
		metrics:           metrics,
	}
}

// LogStreamingRequest creates a metrics-enabled streaming log writer
func (l *FileRequestLoggerWithMetrics) LogStreamingRequest(
	url, method string,
	headers map[string][]string,
	body []byte,
	requestID string,
) (StreamingLogWriter, error) {
	if !l.enabled {
		return &NoOpStreamingLogWriter{}, nil
	}

	// Create the base writer using the parent implementation
	baseWriter, err := l.createBaseStreamingWriter(url, method, headers, body, requestID)
	if err != nil {
		l.metrics.RecordLogError(err)
		return nil, err
	}

	// Wrap with metrics
	return NewMetricsEnabledFileStreamingLogWriter(baseWriter, l.metrics), nil
}

// createBaseStreamingWriter creates the underlying FileStreamingLogWriter
func (l *FileRequestLoggerWithMetrics) createBaseStreamingWriter(
	url, method string,
	headers map[string][]string,
	body []byte,
	requestID string,
) (*FileStreamingLogWriter, error) {
	// This mirrors the logic in FileRequestLogger.LogStreamingRequest
	if err := l.ensureLogsDir(); err != nil {
		return nil, err
	}

	filename := l.generateFilename(url, requestID)
	filePath := filepath.Join(l.logsDir, filename)

	requestHeaders := make(map[string][]string, len(headers))
	for key, values := range headers {
		headerValues := make([]string, len(values))
		copy(headerValues, values)
		requestHeaders[key] = headerValues
	}

	requestBodyPath, errTemp := l.writeRequestBodyTempFile(body)
	if errTemp != nil {
		return nil, errTemp
	}

	responseBodyFile, errCreate := os.CreateTemp(l.logsDir, "response-body-*.tmp")
	if errCreate != nil {
		_ = os.Remove(requestBodyPath)
		return nil, errCreate
	}
	responseBodyPath := responseBodyFile.Name()

	writer := &FileStreamingLogWriter{
		logFilePath:      filePath,
		url:              url,
		method:           method,
		timestamp:        time.Now(),
		requestHeaders:   requestHeaders,
		requestBodyPath:  requestBodyPath,
		responseBodyPath: responseBodyPath,
		responseBodyFile: responseBodyFile,
		chunkChan:        make(chan []byte, 100),
		closeChan:        make(chan struct{}),
		errorChan:        make(chan error, 1),
	}

	go writer.asyncWriter()

	return writer, nil
}

// GetMetrics returns the current metrics
func (l *FileRequestLoggerWithMetrics) GetMetrics() *ports.LogMetrics {
	if l.metrics != nil {
		return l.metrics.GetMetrics()
	}
	return &ports.LogMetrics{}
}

// MetricsCollectorAdapter provides a callback-based interface for log writers
type MetricsCollectorAdapter struct {
	metrics ports.MetricsService
}

// NewMetricsCollectorAdapter creates a new adapter for the given metrics service
func NewMetricsCollectorAdapter(metrics ports.MetricsService) *MetricsCollectorAdapter {
	if metrics == nil {
		metrics = &ports.NoOpMetricsService{}
	}
	return &MetricsCollectorAdapter{metrics: metrics}
}

// OnQueueDepthChanged records queue depth changes
func (a *MetricsCollectorAdapter) OnQueueDepthChanged(depth int) {
	a.metrics.RecordLogQueueDepth(depth)
}

// OnProcessingCompleted records processing completion
func (a *MetricsCollectorAdapter) OnProcessingCompleted(duration time.Duration, bytesProcessed int64, err error) {
	a.metrics.RecordLogProcessingLatency(duration)
	a.metrics.RecordLogWrite(bytesProcessed)
	if err != nil {
		a.metrics.RecordLogError(err)
	}
}

// OnItemsDropped records dropped items
func (a *MetricsCollectorAdapter) OnItemsDropped(count uint64) {
	a.metrics.RecordLogDropCount(count)
}

// Ensure MetricsCollectorAdapter implements the interface
var _ ports.MetricsCollector = (*MetricsCollectorAdapter)(nil)