// NextNVR v0.1.0 — API handlers
// REST endpoints for cameras, configuration, ONVIF discovery, and status.
package main

import (
	"encoding/json"
	"net"
	"net/http"
	"os"
	"strings"
	"time"
)

// handleCameras returns the list of all cameras with runtime status.
// GET /api/cameras
func (s *Server) handleCameras(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		jsonResponse(w, http.StatusMethodNotAllowed, APIResponse{Error: "method not allowed"})
		return
	}

	statuses := make([]CameraStatus, 0, len(s.appConfig.Cameras))
	for _, cam := range s.appConfig.Cameras {
		statuses = append(statuses, CameraStatus{
			CameraConfig: cam,
			Online:       false, // TODO: real stream health check in M2
			Uptime:       "n/a",
			Streams:      0,
		})
	}

	jsonResponse(w, http.StatusOK, APIResponse{Success: true, Data: statuses})
}

// handleCameraByID handles single-camera operations.
// GET  /api/cameras/{id}  — get camera details
// PUT  /api/cameras/{id}  — update camera config
func (s *Server) handleCameraByID(w http.ResponseWriter, r *http.Request) {
	camID := strings.TrimPrefix(r.URL.Path, "/api/cameras/")
	if camID == "" {
		jsonResponse(w, http.StatusBadRequest, APIResponse{Error: "camera ID required"})
		return
	}

	cam, idx := s.findCamera(camID)
	if cam == nil {
		jsonResponse(w, http.StatusNotFound, APIResponse{Error: "camera not found: " + camID})
		return
	}

	switch r.Method {
	case http.MethodGet:
		status := CameraStatus{
			CameraConfig: *cam,
			Online:       false,
			Uptime:       "n/a",
			Streams:      0,
		}
		jsonResponse(w, http.StatusOK, APIResponse{Success: true, Data: status})

	case http.MethodPut:
		var updated CameraConfig
		if err := json.NewDecoder(r.Body).Decode(&updated); err != nil {
			jsonResponse(w, http.StatusBadRequest, APIResponse{Error: "invalid JSON: " + err.Error()})
			return
		}
		updated.ID = camID
		s.appConfig.Cameras[idx] = updated
		jsonResponse(w, http.StatusOK, APIResponse{Success: true, Data: updated})

	default:
		jsonResponse(w, http.StatusMethodNotAllowed, APIResponse{Error: "method not allowed"})
	}
}

// handleConfig handles configuration read/write.
// GET  /api/config  — return current config (without passwords)
// POST /api/config  — save full config to config.yaml
func (s *Server) handleConfig(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case http.MethodGet:
		// Return config with passwords masked.
		safe := *s.appConfig
		for i := range safe.Cameras {
			if safe.Cameras[i].Password != "" {
				safe.Cameras[i].Password = "********"
			}
		}
		jsonResponse(w, http.StatusOK, APIResponse{Success: true, Data: safe})

	case http.MethodPost:
		var newCfg Config
		if err := json.NewDecoder(r.Body).Decode(&newCfg); err != nil {
			jsonResponse(w, http.StatusBadRequest, APIResponse{Error: "invalid JSON: " + err.Error()})
			return
		}

		// Preserve passwords if not provided (masked in UI).
		for i := range newCfg.Cameras {
			if newCfg.Cameras[i].Password == "********" || newCfg.Cameras[i].Password == "" {
				if old := s.findCameraByIP(newCfg.Cameras[i].IP); old != nil {
					newCfg.Cameras[i].Password = old.Password
				}
			}
		}

		*s.appConfig = newCfg

		if err := SaveConfig(*s.appConfig, "/opt/nextnvr/config.yaml"); err != nil {
			// Try saving to the app's config path.
			_ = SaveConfig(*s.appConfig, "config.yaml")
		}

		jsonResponse(w, http.StatusOK, APIResponse{Success: true, Data: "config saved"})

	default:
		jsonResponse(w, http.StatusMethodNotAllowed, APIResponse{Error: "method not allowed"})
	}
}

// handleScan triggers ONVIF network discovery.
// POST /api/scan
// Body: {"method":"range","from":"192.168.1.200","to":"192.168.1.210","username":"admin","password":"..."}
func (s *Server) handleScan(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		jsonResponse(w, http.StatusMethodNotAllowed, APIResponse{Error: "method not allowed"})
		return
	}

	var req ScanRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		// Fall back to legacy stub scan if no body provided.
		s.legacyScan(w)
		return
	}

	if req.From == "" || req.To == "" {
		jsonResponse(w, http.StatusBadRequest, APIResponse{Error: "from and to IP addresses required"})
		return
	}

	fromIP := net.ParseIP(req.From)
	toIP := net.ParseIP(req.To)
	if fromIP == nil || toIP == nil {
		jsonResponse(w, http.StatusBadRequest, APIResponse{Error: "invalid IP address"})
		return
	}

	results := make([]ONVIFDiscovery, 0)
	// Inclusive scan from fromIP to toIP.
	ip := make(net.IP, len(fromIP))
	copy(ip, fromIP)
	for {
		d := probeDevice(ip.String(), req.Username, req.Password)
		results = append(results, d)
		if ip.Equal(toIP) {
			break
		}
		ip = nextIP(ip)
	}

	jsonResponse(w, http.StatusOK, APIResponse{Success: true, Data: results})
}

// legacyScan is the old stub handler for backward compatibility.
func (s *Server) legacyScan(w http.ResponseWriter) {
	type DiscoveredCamera struct {
		IP           string `json:"ip"`
		Manufacturer string `json:"manufacturer"`
		Model        string `json:"model"`
		RTSPMain     string `json:"rtsp_main"`
		RTSPSub      string `json:"rtsp_sub"`
		Found        bool   `json:"found"`
	}
	results := make([]DiscoveredCamera, 0)
	for ip := 201; ip <= 209; ip++ {
		if ip == 204 {
			continue
		}
		ipStr := "192.168.1." + itoa(ip)
		results = append(results, DiscoveredCamera{
			IP:       ipStr,
			Found:    false,
			RTSPMain: "rtsp://" + ipStr + ":554/Streaming/Channels/101",
			RTSPSub:  "rtsp://" + ipStr + ":554/Streaming/Channels/102",
		})
	}
	jsonResponse(w, http.StatusOK, APIResponse{Success: true, Data: results})
}

// nextIP returns the next IP address in sequence.
func nextIP(ip net.IP) net.IP {
	next := make(net.IP, len(ip))
	copy(next, ip)
	for i := len(next) - 1; i >= 0; i-- {
		next[i]++
		if next[i] != 0 {
			break
		}
	}
	return next
}

// handleStatus returns server health and runtime information.
// GET /api/status
func (s *Server) handleStatus(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		jsonResponse(w, http.StatusMethodNotAllowed, APIResponse{Error: "method not allowed"})
		return
	}

	status := map[string]interface{}{
		"version":        Version,
		"cameras_total":  len(s.appConfig.Cameras),
		"cameras_active": 0, // TODO: real counts in M2
		"uptime":         "n/a",
	}
	jsonResponse(w, http.StatusOK, APIResponse{Success: true, Data: status})
}

// handleRecordings returns available recordings for playback.
// GET /api/recordings?cam={id}&preset={today|yesterday|week}&from={date}&to={date}
//
// The recordings directory structure is flat per camera:
//
//	/mnt/recordings/{cam-name}/{YYYY-MM-DD-HH-MM}.mp4
//
// In-progress recordings use .part.mp4 suffix and are excluded from results.
func (s *Server) handleRecordings(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		jsonResponse(w, http.StatusMethodNotAllowed, APIResponse{Error: "method not allowed"})
		return
	}

	camID := r.URL.Query().Get("cam")
	preset := r.URL.Query().Get("preset")
	fromStr := r.URL.Query().Get("from")
	toStr := r.URL.Query().Get("to")

	type Clip struct {
		Name string `json:"name"`
		Path string `json:"path"`
		Size int64  `json:"size"`
		Time string `json:"time"`
		Live bool   `json:"live"`
	}

	clips := make([]Clip, 0)

	if camID == "" {
		jsonResponse(w, http.StatusOK, APIResponse{Success: true, Data: clips})
		return
	}

	// Resolve camera name for directory lookup.
	cam, _ := s.findCamera(camID)
	camDir := camID
	if cam != nil && cam.Name != "" {
		camDir = cam.Name
	}

	// Determine date range from preset or custom range.
	var fromTime, toTime time.Time
	now := time.Now()

	switch preset {
	case "today":
		fromTime = time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
		toTime = now
	case "yesterday":
		yesterday := now.AddDate(0, 0, -1)
		fromTime = time.Date(yesterday.Year(), yesterday.Month(), yesterday.Day(), 0, 0, 0, 0, now.Location())
		toTime = time.Date(yesterday.Year(), yesterday.Month(), yesterday.Day(), 23, 59, 59, 0, now.Location())
	case "week":
		fromTime = now.AddDate(0, 0, -7)
		toTime = now
	default:
		// Parse custom date range.
		if fromStr != "" {
			fromTime, _ = time.Parse("2006-01-02", fromStr)
		}
		if toStr != "" {
			toTime, _ = time.Parse("2006-01-02", toStr)
			toTime = toTime.Add(24*time.Hour - time.Second) // end of day
		}
		if fromStr == "" {
			fromTime = now.AddDate(0, 0, -1) // default: last 24h
		}
		if toStr == "" {
			toTime = now
		}
	}

	// Scan the flat camera directory.
	recDir := s.appConfig.Storage.RecordingsPath
	scanDir := recDir + "/" + camDir

	entries, err := os.ReadDir(scanDir)
	if err != nil {
		// Directory doesn't exist yet — no recordings.
		jsonResponse(w, http.StatusOK, APIResponse{Success: true, Data: clips})
		return
	}

	for _, entry := range entries {
		if entry.IsDir() {
			continue
		}
		name := entry.Name()

		// Skip in-progress .part files.
		isPart := strings.HasSuffix(strings.ToLower(name), ".part.mp4")
		isMP4 := strings.HasSuffix(strings.ToLower(name), ".mp4")

		if !isMP4 && !isPart {
			continue
		}

		// Extract timestamp from filename: YYYY-MM-DD-HH-MM.mp4
		base := strings.TrimSuffix(strings.TrimSuffix(name, ".mp4"), ".part")
		fileTime, parseErr := time.Parse("2006-01-02-15-04", base)

		info, statErr := entry.Info()
		if statErr != nil {
			continue
		}

		clip := Clip{
			Name: name,
			Path: camDir + "/" + name,
			Size: info.Size(),
			Live: isPart,
		}

		if parseErr == nil {
			clip.Time = fileTime.Format("15:04")
			// Apply date filter.
			if !fromTime.IsZero() && fileTime.Before(fromTime) {
				continue
			}
			if !toTime.IsZero() && fileTime.After(toTime) {
				continue
			}
		}

		clips = append([]Clip{clip}, clips...) // prepend = newest first
	}

	jsonResponse(w, http.StatusOK, APIResponse{Success: true, Data: clips})
}

// findCamera locates a camera by ID.
func (s *Server) findCamera(id string) (*CameraConfig, int) {
	for i, cam := range s.appConfig.Cameras {
		if cam.ID == id {
			return &s.appConfig.Cameras[i], i
		}
	}
	return nil, -1
}

// findCameraByIP locates a camera by IP address.
func (s *Server) findCameraByIP(ip string) *CameraConfig {
	for i := range s.appConfig.Cameras {
		if s.appConfig.Cameras[i].IP == ip {
			return &s.appConfig.Cameras[i]
		}
	}
	return nil
}

// itoa is a simple int-to-string helper (avoids importing strconv).
func itoa(i int) string {
	if i == 0 {
		return "0"
	}
	digits := ""
	for n := i; n > 0; n /= 10 {
		digits = string(rune('0'+n%10)) + digits
	}
	return digits
}