package main

import (
	"context"
	"encoding/json"
	"fmt"
	"log/slog"
	"net/http"
	"os/exec"
	"slices"
	"strconv"
	"strings"
	"time"
	"watch-tool/models"
)

type WebService struct {
	server  *http.Server
	storage StorageInterface
	config  *Config
}

func LoggingMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		slog.Debug("WebService", "Remote-Address", r.RemoteAddr, "Method", r.Method, "Path", r.URL.Path)
		next.ServeHTTP(w, r)
	})
}

func NewWebService(config *Config, storage StorageInterface) *WebService {
	mux := http.NewServeMux()

	ws := &WebService{
		storage: storage,
		config:  config,
	}

	mux.HandleFunc("GET /health", ws.handleHealth)
	mux.HandleFunc("GET /logs", ws.handleLogs)
	mux.HandleFunc("GET /export", ws.handleExport)
	mux.HandleFunc("GET /stats", ws.handleStats)
	mux.HandleFunc("GET /stats/{service}", ws.handleServiceStats)

	loggedMux := LoggingMiddleware(mux)

	addr := fmt.Sprintf("%s:%d", config.WebService.Host, config.WebService.Port)
	ws.server = &http.Server{
		Addr:         addr,
		Handler:      loggedMux,
		ReadTimeout:  30 * time.Second,
		WriteTimeout: 300 * time.Second,
		IdleTimeout:  60 * time.Second,
	}

	return ws
}

func (ws *WebService) Start(ctx context.Context) error {
	go func() {
		<-ctx.Done()
		shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		defer cancel()

		if err := ws.server.Shutdown(shutdownCtx); err != nil {
			slog.Error("web service shutdown error", "error", err)
		}
	}()

	slog.Info("Starting web service", "address", ws.server.Addr)

	if err := ws.server.ListenAndServe(); err != http.ErrServerClosed {
		return fmt.Errorf("web service error: %w", err)
	}

	return nil
}

func (ws *WebService) handleHealth(w http.ResponseWriter, r *http.Request) {

	status := map[string]any{
		"status":    "healthy",
		"timestamp": time.Now(),
		"storage":   "sqlite",
	}

	ctx, cancel := context.WithTimeout(r.Context(), 5*time.Second)
	defer cancel()

	_, err := ws.storage.Query(ctx, StorageQuery{
		Limit: 1,
	})

	if err != nil {
		status["storage_status"] = "unhealthy"
		status["storage_error"] = err.Error()
		w.WriteHeader(http.StatusServiceUnavailable)
	} else {
		status["storage_status"] = "healthy"
	}
	statusMap := make(map[string]any)
	statusMap["watch"] = status

	for _, service := range ws.config.Services {
		statusCommand := []string{"sudo", "systemctl", "status", service.Name, "--no-pager"}
		if service.Enabled {
			serviceStatus, err := exec.Command(statusCommand[0], statusCommand[1:]...).Output()
			if err != nil {
				slog.Error("error executing status command", "error", err)
				continue
			}
			lines := strings.SplitSeq(string(serviceStatus), "\n")
			for line := range lines {
				if strings.Contains(line, "Active:") {
					serviceHealth, found := strings.CutPrefix(strings.TrimSpace(line), "Active:")
					if found {
						statusMap[service.Name] = map[string]any{"status": serviceHealth, "timestamp": time.Now()}
					}
				}
			}
		}
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(statusMap)
}

func (ws *WebService) handleLogs(w http.ResponseWriter, r *http.Request) {

	query := ws.parseLogsQuery(r)

	ctx, cancel := context.WithTimeout(r.Context(), 30*time.Second)
	defer cancel()

	entries, err := ws.storage.Query(ctx, query)
	if err != nil {
		http.Error(w, fmt.Sprintf("Query error: %v", err), http.StatusInternalServerError)
		return
	}

	response := map[string]any{
		"entries": entries,
		"count":   len(entries),
		"query":   query,
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(response)
}

func (ws *WebService) handleExport(w http.ResponseWriter, r *http.Request) {

	query := ws.parseLogsQuery(r)

	ctx, cancel := context.WithTimeout(r.Context(), 300*time.Second)
	defer cancel()

	entries, err := ws.storage.Query(ctx, query)
	if err != nil {
		http.Error(w, fmt.Sprintf("Export query error: %v", err), http.StatusInternalServerError)
		return
	}

	filename := fmt.Sprintf("watch_export_%s.json", time.Now().Format("20060102_150405"))
	w.Header().Set("Content-Type", "application/json")
	w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=%s", filename))

	exportData := map[string]any{
		"export_info": map[string]any{
			"timestamp":   time.Now(),
			"entry_count": len(entries),
			"query":       query,
			"exported_by": "watch",
		},
		"entries": entries,
	}

	if err := json.NewEncoder(w).Encode(exportData); err != nil {
		slog.Error("Failed to encode export data", "error", err)
		return
	}

	slog.Info("Data exported", "count", len(entries), "query", query)
}

func (ws *WebService) handleStats(w http.ResponseWriter, r *http.Request) {

	ctx, cancel := context.WithTimeout(r.Context(), 10*time.Second)
	defer cancel()

	allEntries, err := ws.storage.Query(ctx, StorageQuery{})
	if err != nil {
		http.Error(w, fmt.Sprintf("Stats query error: %v", err), http.StatusInternalServerError)
		return
	}

	recentEntries, err := ws.storage.Query(ctx, StorageQuery{
		StartTime: time.Now().Add(-time.Hour),
	})
	if err != nil {
		slog.Error("Failed to query recent entries", "error", err)
		recentEntries = []models.LogMessage{}
	}

	stats := map[string]any{
		"total_entries":  len(allEntries),
		"recent_entries": len(recentEntries),
		"timestamp":      time.Now(),
	}

	typeCounts := make(map[string]int)
	serviceCounts := make(map[string]int)
	toolCounts := make(map[string]int)

	for _, entry := range allEntries {
		typeCounts[entry.Type]++
		if entry.Service != "" {
			serviceCounts[entry.Service]++
		}
		if entry.Tool != "" {
			toolCounts[entry.Tool]++
		}
	}

	stats["by_type"] = typeCounts
	stats["by_service"] = serviceCounts
	stats["by_tool"] = toolCounts

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(stats)
}

func (ws *WebService) handleServiceStats(w http.ResponseWriter, r *http.Request) {
	service := r.PathValue("service")
	if service == "" {
		http.Error(w, "Service parameter is missing", http.StatusBadRequest)
		return
	}

	timeRangeStr := r.URL.Query().Get("time_range")
	var startTime time.Time
	if timeRangeStr == "" {
		startTime = time.Now().Add(-24 * time.Hour)
	} else {
		duration, err := time.ParseDuration(timeRangeStr)
		if err != nil {
			http.Error(w, fmt.Sprintf("Invalid time_range: %v", err), http.StatusBadRequest)
			return
		}
		startTime = time.Now().Add(-duration)
	}

	query := StorageQuery{
		Service:   service,
		StartTime: startTime,
		Limit:     0,
		OrderDesc: false,
	}

	ctx, cancel := context.WithTimeout(r.Context(), 30*time.Second)
	defer cancel()

	entries, err := ws.storage.Query(ctx, query)
	if err != nil {
		slog.Error("Failed to query service stats", "service", service, "error", err)
		http.Error(w, fmt.Sprintf("Query error: %v", err), http.StatusInternalServerError)
		return
	}

	uniqueTransfersTotal := make(map[string]struct{})
	uniqueTransfersIncoming := make(map[string]struct{})
	uniqueTransfersOutgoing := make(map[string]struct{})
	uniqueTransfersNil := make(map[string]struct{})

	for _, entry := range entries {
		var identifier string
		var direction string

		if entry.Fields != nil {
			if id, ok := entry.Fields["transfer_id"].(string); ok {
				identifier = id
			} else if id, ok := entry.Fields["correlation_id"].(string); ok {
				identifier = id
			}

			if dir, ok := entry.Fields["direction"].(string); ok {
				direction = dir
			} else if rawName, ok := entry.Fields["transfer_name_raw"].(string); ok {
				if strings.Contains(rawName, "-in") {
					direction = "incoming"
				} else if strings.Contains(rawName, "-out") {
					direction = "outgoing"
				}
			}

			if direction == "" && entry.Service == "tixstream" {
				if strings.HasPrefix(entry.Raw, "in:") {
					direction = "incoming"
				} else if strings.HasPrefix(entry.Raw, "out:") {
					direction = "outgoing"
				}
			}
		}

		if identifier == "" && entry.ServiceInformation != nil {
			switch v := entry.ServiceInformation.(type) {
			case models.TSTransferInfo:
				identifier = v.TransferID
				direction = v.Direction
			case *models.TSTransferInfo:
				identifier = v.TransferID
				direction = v.Direction
			case models.TJMTransferInfo:
				identifier = v.TransferID
				direction = v.Direction
			case *models.TJMTransferInfo:
				identifier = v.TransferID
				direction = v.Direction
			case map[string]any:
				identifier, _ = v["transfer_identifier"].(string)
				direction, _ = v["direction"].(string)
			}
		}

		if identifier != "" && identifier != "no_transfer_id" {
			uniqueTransfersTotal[identifier] = struct{}{}

			dirLower := strings.ToLower(direction)

			if strings.Contains(dirLower, "outgoing") || strings.Contains(dirLower, "out") {
				uniqueTransfersOutgoing[identifier] = struct{}{}
			} else if strings.Contains(dirLower, "incoming") || strings.Contains(dirLower, "in") {
				uniqueTransfersIncoming[identifier] = struct{}{}
			} else {
				uniqueTransfersNil[identifier] = struct{}{}
			}
		}
	}

	stats := map[string]any{
		"service":    service,
		"start_time": startTime,
		"end_time":   time.Now(),
		"transfer_counts": map[string]any{
			"total":                    len(uniqueTransfersTotal),
			"incoming":                 len(uniqueTransfersIncoming),
			"outgoing":                 len(uniqueTransfersOutgoing),
			"nil_or_unknown_direction": len(uniqueTransfersNil),
		},
		"entry_count": len(entries),
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(stats)
}

func (ws *WebService) parseLogsQuery(r *http.Request) StorageQuery {
	query := StorageQuery{
		Limit:     100,
		OrderBy:   "timestamp",
		OrderDesc: true,
	}

	if limitStr := r.URL.Query().Get("limit"); limitStr != "" {
		if limit, err := strconv.Atoi(limitStr); err == nil && limit > 0 {
			if limit > 10000 {
				limit = 10000
			}
			query.Limit = limit
		}
	}

	if offsetStr := r.URL.Query().Get("offset"); offsetStr != "" {
		if offset, err := strconv.Atoi(offsetStr); err == nil && offset >= 0 {
			query.Offset = offset
		}
	}

	if startTime := r.URL.Query().Get("start_time"); startTime != "" {
		if t, err := time.Parse(time.RFC3339, startTime); err == nil {
			query.StartTime = t
		}
	}

	if endTime := r.URL.Query().Get("end_time"); endTime != "" {
		if t, err := time.Parse(time.RFC3339, endTime); err == nil {
			query.EndTime = t
		}
	}

	if service := r.URL.Query().Get("service"); service != "" {
		query.Service = strings.TrimSpace(service)
	}

	if tool := r.URL.Query().Get("tool"); tool != "" {
		query.Tool = strings.TrimSpace(tool)
	}

	if logLevel := r.URL.Query().Get("log_level"); logLevel != "" {
		query.LogLevel = strings.TrimSpace(logLevel)
	}

	if entryType := r.URL.Query().Get("type"); entryType != "" {
		query.Type = strings.TrimSpace(entryType)
	}

	if orderBy := r.URL.Query().Get("order_by"); orderBy != "" {
		validFields := []string{"timestamp", "service", "tool", "type", "log_level"}
		if slices.Contains(validFields, orderBy) {
			query.OrderBy = orderBy
		}
	}

	if orderDesc := r.URL.Query().Get("order_desc"); orderDesc != "" {
		query.OrderDesc = orderDesc == "true"
	}

	return query
}