package api

import (
	"encoding/json"
	"fmt"
	"net/http"
	"net/url"
	"strings"
	"time"

	"3588AdminBackend/internal/models"
	"3588AdminBackend/internal/service"
	"github.com/go-chi/chi/v5"
)

type Handler struct {
	discovery *service.DiscoveryService
	registry  *service.RegistryService
	agent     *service.AgentClient
	tasks     *service.TaskService
	templates *service.TemplateService
}

func NewHandler(discovery *service.DiscoveryService, registry *service.RegistryService, agent *service.AgentClient, tasks *service.TaskService, templates *service.TemplateService) *Handler {
	return &Handler{
		discovery: discovery,
		registry:  registry,
		agent:     agent,
		tasks:     tasks,
		templates: templates,
	}
}

func (h *Handler) Search(w http.ResponseWriter, r *http.Request) {
	var req struct {
		TimeoutMs int `json:"timeout_ms"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		req.TimeoutMs = 1200 // Default
	}

	items, err := h.discovery.Search(req.TimeoutMs)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	json.NewEncoder(w).Encode(map[string]interface{}{
		"items": items,
	})
}

func (h *Handler) ListDevices(w http.ResponseWriter, r *http.Request) {
	h.ensureDevicesLoaded()
	items := h.registry.GetDevices()
	json.NewEncoder(w).Encode(map[string]interface{}{
		"items": items,
	})
}

func (h *Handler) CreateDevice(w http.ResponseWriter, r *http.Request) {
	var req struct {
		DeviceID   string `json:"device_id"`
		DeviceName string `json:"device_name"`
		IP         string `json:"ip"`
		AgentPort  int    `json:"agent_port"`
		MediaPort  int    `json:"media_port"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "invalid request body", http.StatusBadRequest)
		return
	}
	if req.DeviceID == "" || req.IP == "" {
		http.Error(w, "device_id and ip are required", http.StatusBadRequest)
		return
	}
	if req.AgentPort == 0 {
		req.AgentPort = 9100
	}
	if req.MediaPort == 0 {
		req.MediaPort = 9000
	}

	dev := &models.Device{
		DeviceID:   req.DeviceID,
		DeviceName: req.DeviceName,
		IP:         req.IP,
		AgentPort:  req.AgentPort,
		MediaPort:  req.MediaPort,
		Online:     true,
		LastSeenMs: time.Now().UnixMilli(),
	}
	h.registry.UpdateDevice(dev)
	json.NewEncoder(w).Encode(map[string]interface{}{"ok": true})
}

func (h *Handler) GetDevice(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	dev, ok := h.findDevice(id)
	if !ok {
		http.Error(w, "device not found", http.StatusNotFound)
		return
	}
	json.NewEncoder(w).Encode(dev)
}

func (h *Handler) findDevice(id string) (*models.Device, bool) {
	h.ensureDevicesLoaded()
	devices := h.registry.GetDevices()
	for _, d := range devices {
		if d.DeviceID == id {
			return d, true
		}
	}
	if h.discovery != nil {
		_, _ = h.discovery.SearchDefault()
		devices = h.registry.GetDevices()
		for _, d := range devices {
			if d.DeviceID == id {
				return d, true
			}
		}
	}
	return nil, false
}

func (h *Handler) ensureDevicesLoaded() {
	if h.registry == nil || h.discovery == nil {
		return
	}
	if len(h.registry.GetDevices()) > 0 {
		return
	}
	_, _ = h.discovery.SearchDefault()
}

func (h *Handler) ProxyAgent(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	name := chi.URLParam(r, "name")
	dev, ok := h.findDevice(id)
	if !ok {
		http.Error(w, "device not found", http.StatusNotFound)
		return
	}
	var agentPath string
	method := r.Method

	switch {
	case r.URL.Path == fmt.Sprintf("/api/devices/%s/info", id):
		agentPath = "/v1/info"
	case r.URL.Path == fmt.Sprintf("/api/devices/%s/config/status", id):
		agentPath = "/v1/config/status"
	case r.URL.Path == fmt.Sprintf("/api/devices/%s/config/candidate", id):
		agentPath = "/v1/config/candidate"
		method = "PUT"
	case r.URL.Path == fmt.Sprintf("/api/devices/%s/config/candidate/apply", id):
		agentPath = "/v1/config/candidate/apply"
		method = "POST"
	case r.URL.Path == fmt.Sprintf("/api/devices/%s/reload", id):
		agentPath = "/v1/media-server/reload"
		method = "POST"
	case r.URL.Path == fmt.Sprintf("/api/devices/%s/rollback", id):
		agentPath = "/v1/media-server/rollback"
		method = "POST"
	case r.URL.Path == fmt.Sprintf("/api/devices/%s/media-server/start", id):
		agentPath = "/v1/media-server/start"
		method = "POST"
	case r.URL.Path == fmt.Sprintf("/api/devices/%s/media-server/restart", id):
		agentPath = "/v1/media-server/restart"
		method = "POST"
	case r.URL.Path == fmt.Sprintf("/api/devices/%s/media-server/stop", id):
		agentPath = "/v1/media-server/stop"
		method = "POST"
	case r.URL.Path == fmt.Sprintf("/api/devices/%s/media-server/status", id):
		agentPath = "/v1/media-server/status"
	case r.URL.Path == fmt.Sprintf("/api/devices/%s/graphs", id):
		agentPath = "/v1/graphs"
	case name != "" && r.URL.Path == fmt.Sprintf("/api/devices/%s/graphs/%s", id, name):
		agentPath = "/v1/graphs/" + url.PathEscape(name)
	case r.URL.Path == fmt.Sprintf("/api/devices/%s/logs", id):
		agentPath = "/v1/logs/recent"
		if q := r.URL.RawQuery; q != "" {
			agentPath += "?" + q
		}
	case r.URL.Path == fmt.Sprintf("/api/devices/%s/config/apply", id):
		agentPath = "/v1/config"
		method = "PUT"
	case r.URL.Path == fmt.Sprintf("/api/devices/%s/models", id):
		agentPath = "/v1/models"
	default:
		http.Error(w, "path not mapped", http.StatusNotFound)
		return
	}

	contentType := r.Header.Get("Content-Type")
	resp, code, err := h.agent.DoStream(method, dev.IP, dev.AgentPort, agentPath, r.Body, contentType, r.ContentLength)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Update online status on successful response
	if code < 500 && h.registry != nil {
		h.registry.TouchDevice(id)
	}

	w.WriteHeader(code)
	w.Write(resp)
}

// ProxyAgentV1 proxies any request under /api/devices/{id}/v1/* to the device agent as-is (path preserved).
func (h *Handler) ProxyAgentV1(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	dev, ok := h.findDevice(id)
	if !ok {
		http.Error(w, "device not found", http.StatusNotFound)
		return
	}
	prefix := fmt.Sprintf("/api/devices/%s", id)
	agentPath := strings.TrimPrefix(r.URL.Path, prefix)
	if !strings.HasPrefix(agentPath, "/v1/") && agentPath != "/v1" {
		http.Error(w, "path not mapped", http.StatusNotFound)
		return
	}
	if q := r.URL.RawQuery; q != "" {
		agentPath += "?" + q
	}

	contentType := r.Header.Get("Content-Type")
	resp, code, err := h.agent.DoStream(r.Method, dev.IP, dev.AgentPort, agentPath, r.Body, contentType, r.ContentLength)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Update online status on successful response
	if code < 500 && h.registry != nil {
		h.registry.TouchDevice(id)
	}

	w.WriteHeader(code)
	_, _ = w.Write(resp)
}

func (h *Handler) CreateTask(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Type      string      `json:"type"`
		DeviceIDs []string    `json:"device_ids"`
		Payload   interface{} `json:"payload"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "invalid request body", http.StatusBadRequest)
		return
	}

	task, err := h.tasks.CreateTask(req.Type, req.DeviceIDs, req.Payload)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	json.NewEncoder(w).Encode(map[string]string{"task_id": task.ID})
}

func (h *Handler) ListTasks(w http.ResponseWriter, r *http.Request) {
	if h.tasks == nil {
		http.Error(w, "task service not initialized", http.StatusInternalServerError)
		return
	}

	items := h.tasks.ListTasks()
	json.NewEncoder(w).Encode(map[string]interface{}{
		"items": items,
	})
}

func (h *Handler) TaskEvents(w http.ResponseWriter, r *http.Request) {
	taskID := chi.URLParam(r, "id")
	ch, cleanup := h.tasks.Subscribe(taskID)
	defer cleanup()

	w.Header().Set("Content-Type", "text/event-stream")
	w.Header().Set("Cache-Control", "no-cache")
	w.Header().Set("Connection", "keep-alive")

	flusher, ok := w.(http.Flusher)
	if !ok {
		http.Error(w, "SSE not supported", http.StatusInternalServerError)
		return
	}

	for {
		select {
		case <-r.Context().Done():
			return
		case update := <-ch:
			data, _ := json.Marshal(update)
			fmt.Fprintf(w, "event: device_update\ndata: %s\n\n", data)
			flusher.Flush()
		}
	}
}

func (h *Handler) ListTemplates(w http.ResponseWriter, r *http.Request) {
	list, err := h.templates.ListTemplates()
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	json.NewEncoder(w).Encode(list)
}

func (h *Handler) GetTemplate(w http.ResponseWriter, r *http.Request) {
	name := chi.URLParam(r, "name")
	t, err := h.templates.GetTemplate(name)
	if err != nil {
		http.Error(w, err.Error(), http.StatusNotFound)
		return
	}
	json.NewEncoder(w).Encode(t)
}

func (h *Handler) UploadModel(w http.ResponseWriter, r *http.Request) {
	id := chi.URLParam(r, "id")
	dev, ok := h.findDevice(id)
	if !ok {
		http.Error(w, "device not found", http.StatusNotFound)
		return
	}

	// Parse multipart
	if err := r.ParseMultipartForm(100 << 20); err != nil { // 100MB
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	name := r.FormValue("name")
	file, hdr, err := r.FormFile("file")
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	defer file.Close()

	if name == "" {
		http.Error(w, "name is required", http.StatusBadRequest)
		return
	}

	// Forward to agent
	agentPath := fmt.Sprintf("/v1/models/%s", name)
	resp, code, err := h.agent.DoStream("PUT", dev.IP, dev.AgentPort, agentPath, file, "application/octet-stream", hdr.Size)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	w.WriteHeader(code)
	w.Write(resp)
}