package httpapi

import (
	"context"
	"encoding/hex"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"mime"
	"net/http"
	"os"
	"regexp"
	"strconv"
	"strings"
	"time"

	"rk3588sys/agent/internal/config"
	"rk3588sys/agent/internal/files"
	"rk3588sys/agent/internal/mediaserver"
	"rk3588sys/agent/internal/modelstore"
	"rk3588sys/agent/internal/procctl"
	"rk3588sys/agent/internal/sysinfo"
)

type Server struct {
	agentCfg  config.AgentConfig
	ms        *mediaserver.Client
	store     *modelstore.Store
	proc      *procctl.Controller
	deviceID  string
	hostname  string
	agentPort int
	mediaPort int
	version   string
	gitSHA    string
}

type InfoResponse struct {
	DeviceID     string `json:"device_id"`
	DeviceName   string `json:"device_name"`
	Hostname     string `json:"hostname"`
	IP           string `json:"ip"`
	AgentPort    int    `json:"agent_port"`
	MediaPort    int    `json:"media_port"`
	Version      string `json:"version"`
	GitSHA       string `json:"git_sha"`
	ConfigPath   string `json:"config_path"`
	LastGoodPath string `json:"last_good_path"`
	UptimeSec    int64  `json:"uptime_sec"`
}

func New(agentCfg config.AgentConfig, baseDir string, ms *mediaserver.Client, store *modelstore.Store, deviceID string, agentPort int, mediaPort int, version, gitSHA string) http.Handler {
	var pc *procctl.Controller
	if agentCfg.MediaServerProcess.Enable {
		pc = procctl.New(agentCfg, baseDir)
	}
	s := &Server{
		agentCfg:  agentCfg,
		ms:        ms,
		store:     store,
		proc:      pc,
		deviceID:  deviceID,
		hostname:  sysinfo.Hostname(),
		agentPort: agentPort,
		mediaPort: mediaPort,
		version:   version,
		gitSHA:    gitSHA,
	}

	mux := http.NewServeMux()
	mux.HandleFunc("/v1/info", s.handleInfo)
	mux.HandleFunc("/v1/config", s.handleConfig)
	mux.HandleFunc("/v1/config/ui/schema", s.handleConfigUISchema)
	mux.HandleFunc("/v1/config/ui/state", s.handleConfigUIState)
	mux.HandleFunc("/v1/config/ui/plan", s.handleConfigUIPlan)
	mux.HandleFunc("/v1/config/ui/apply", s.handleConfigUIApply)
	mux.HandleFunc("/v1/face-gallery", s.handleFaceGallery)
	mux.HandleFunc("/v1/face-gallery/reload", s.handleFaceGalleryReload)
	mux.HandleFunc("/v1/models", s.handleModelsList)
	mux.HandleFunc("/v1/models/", s.handleModelUpload)
	mux.HandleFunc("/v1/media-server/reload", s.handleMediaReload)
	mux.HandleFunc("/v1/media-server/rollback", s.handleMediaRollback)
	mux.HandleFunc("/v1/media-server/start", s.handleMediaStart)
	mux.HandleFunc("/v1/media-server/restart", s.handleMediaRestart)
	mux.HandleFunc("/v1/media-server/stop", s.handleMediaStop)
	mux.HandleFunc("/v1/media-server/status", s.handleMediaStatus)
	mux.HandleFunc("/v1/graphs", s.handleGraphs)
	mux.HandleFunc("/v1/graphs/", s.handleGraphDetail)
	mux.HandleFunc("/v1/logs/recent", s.handleLogsRecent)

	return mux
}

func (s *Server) handleInfo(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		errorJSON(w, http.StatusMethodNotAllowed, "method not allowed")
		return
	}
	if !s.authorize(r, false) {
		errorJSON(w, http.StatusUnauthorized, "unauthorized")
		return
	}

	ip := sysinfo.PrimaryIPv4()
	resp := InfoResponse{
		DeviceID:     s.deviceID,
		DeviceName:   s.agentCfg.DeviceName,
		Hostname:     s.hostname,
		IP:           ip,
		AgentPort:    s.agentPort,
		MediaPort:    s.mediaPort,
		Version:      s.version,
		GitSHA:       s.gitSHA,
		ConfigPath:   s.agentCfg.ConfigPath,
		LastGoodPath: s.agentCfg.ConfigPath + ".last_good.json",
		UptimeSec:    sysinfo.UptimeSec(),
	}
	writeJSON(w, http.StatusOK, resp)
}

func (s *Server) handleConfig(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case http.MethodGet:
		if !s.authorize(r, false) {
			errorJSON(w, http.StatusUnauthorized, "unauthorized")
			return
		}
		b, err := os.ReadFile(s.agentCfg.ConfigPath)
		if err != nil {
			if os.IsNotExist(err) {
				errorJSON(w, http.StatusNotFound, "not found")
				return
			}
			errorJSON(w, http.StatusInternalServerError, "internal error: read config failed: "+err.Error())
			return
		}
		var tmp any
		if err := json.Unmarshal(b, &tmp); err != nil {
			errorJSON(w, http.StatusInternalServerError, "internal error: config is not valid json: "+err.Error())
			return
		}
		writeRawJSON(w, http.StatusOK, b)
		return

	case http.MethodPut:
		if !s.authorize(r, true) {
			errorJSON(w, http.StatusUnauthorized, "unauthorized")
			return
		}
		if mt, _, err := mime.ParseMediaType(r.Header.Get("Content-Type")); err != nil || mt != "application/json" {
			errorJSON(w, http.StatusBadRequest, "validation failed: Content-Type must be application/json")
			return
		}

		const maxConfigBytes = int64(20 << 20)
		r.Body = http.MaxBytesReader(w, r.Body, maxConfigBytes)
		body, err := io.ReadAll(r.Body)
		if err != nil {
			if strings.Contains(err.Error(), "request body too large") {
				errorJSON(w, http.StatusRequestEntityTooLarge, "payload too large")
				return
			}
			errorJSON(w, http.StatusBadRequest, "invalid json: "+err.Error())
			return
		}
		if len(body) == 0 {
			errorJSON(w, http.StatusBadRequest, "validation failed: empty body")
			return
		}
		var tmp any
		if err := json.Unmarshal(body, &tmp); err != nil {
			errorJSON(w, http.StatusBadRequest, "invalid json: "+err.Error())
			return
		}

		if err := s.applyRootConfigBytes(r.Context(), body); err != nil {
			errorJSON(w, http.StatusInternalServerError, "internal error: "+err.Error())
			return
		}
		writeJSON(w, http.StatusOK, map[string]any{"ok": true})
		return
	default:
		errorJSON(w, http.StatusMethodNotAllowed, "method not allowed")
		return
	}
}

func (s *Server) applyRootConfigBytes(ctx context.Context, body []byte) error {
	if err := files.WriteFileAtomic(s.agentCfg.ConfigPath, append(body, '\n'), 0o644); err != nil {
		return fmt.Errorf("write config failed: %w", err)
	}

	ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
	defer cancel()
	if err := s.ms.Reload(ctx); err != nil {
		rerr := err
		rbErr := s.ms.Rollback(ctx)
		if rbErr != nil {
			return fmt.Errorf("reload failed: %v; rollback failed: %v", rerr, rbErr)
		}
		return fmt.Errorf("reload failed: %v; rollback ok", rerr)
	}
	return nil
}

var modelNameRE = regexp.MustCompile(`^[A-Za-z0-9._-]+$`)

func (s *Server) handleModelUpload(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPut {
		errorJSON(w, http.StatusMethodNotAllowed, "method not allowed")
		return
	}
	if !s.authorize(r, true) {
		errorJSON(w, http.StatusUnauthorized, "unauthorized")
		return
	}
	if mt, _, err := mime.ParseMediaType(r.Header.Get("Content-Type")); err != nil || mt != "application/octet-stream" {
		errorJSON(w, http.StatusBadRequest, "validation failed: Content-Type must be application/octet-stream")
		return
	}
	name := strings.TrimPrefix(r.URL.Path, "/v1/models/")
	name = strings.TrimSpace(name)
	if name == "" || strings.Contains(name, "/") || strings.Contains(name, "\\") {
		errorJSON(w, http.StatusBadRequest, "validation failed: invalid name")
		return
	}
	if !modelNameRE.MatchString(name) {
		errorJSON(w, http.StatusBadRequest, "validation failed: invalid name")
		return
	}
	if r.ContentLength <= 0 {
		errorJSON(w, http.StatusBadRequest, "validation failed: missing Content-Length")
		return
	}

	expected := strings.TrimSpace(r.Header.Get("X-Model-Sha256"))
	if expected != "" {
		if len(expected) != 64 {
			errorJSON(w, http.StatusBadRequest, "validation failed: invalid X-Model-Sha256")
			return
		}
		if _, err := hex.DecodeString(expected); err != nil {
			errorJSON(w, http.StatusBadRequest, "validation failed: invalid X-Model-Sha256")
			return
		}
	}

	item, err := s.store.Upload(name, r.Body, r.ContentLength, expected)
	if err != nil {
		if errors.Is(err, modelstore.ErrPayloadTooLarge) {
			errorJSON(w, http.StatusRequestEntityTooLarge, "payload too large")
			return
		}
		if strings.Contains(err.Error(), "sha256 mismatch") {
			errorJSON(w, http.StatusBadRequest, "validation failed: sha256 mismatch")
			return
		}
		errorJSON(w, http.StatusInternalServerError, "internal error: "+err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{
		"ok":     true,
		"name":   item.Name,
		"sha256": item.Sha256,
		"path":   item.Path,
		"size":   item.Size,
	})
}

func (s *Server) handleModelsList(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		errorJSON(w, http.StatusMethodNotAllowed, "method not allowed")
		return
	}
	if !s.authorize(r, false) {
		errorJSON(w, http.StatusUnauthorized, "unauthorized")
		return
	}
	m, err := s.store.List()
	if err != nil {
		errorJSON(w, http.StatusInternalServerError, "internal error: "+err.Error())
		return
	}
	writeJSON(w, http.StatusOK, m)
}

func (s *Server) handleMediaReload(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		errorJSON(w, http.StatusMethodNotAllowed, "method not allowed")
		return
	}
	if !s.authorize(r, true) {
		errorJSON(w, http.StatusUnauthorized, "unauthorized")
		return
	}
	if err := s.ms.Reload(r.Context()); err != nil {
		errorJSON(w, http.StatusInternalServerError, "internal error: "+err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"ok": true})
}

func (s *Server) handleMediaRollback(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		errorJSON(w, http.StatusMethodNotAllowed, "method not allowed")
		return
	}
	if !s.authorize(r, true) {
		errorJSON(w, http.StatusUnauthorized, "unauthorized")
		return
	}
	if err := s.ms.Rollback(r.Context()); err != nil {
		errorJSON(w, http.StatusInternalServerError, "internal error: "+err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"ok": true})
}

type mediaProcReq struct {
	Config string `json:"config"`
}

func (s *Server) handleMediaStart(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		errorJSON(w, http.StatusMethodNotAllowed, "method not allowed")
		return
	}
	if !s.authorize(r, true) {
		errorJSON(w, http.StatusUnauthorized, "unauthorized")
		return
	}
	if s.proc == nil || !s.proc.Enabled() {
		errorJSON(w, http.StatusNotImplemented, "not supported")
		return
	}

	req, err := readOptionalJSON[mediaProcReq](w, r, 1<<20)
	if err != nil {
		errorJSON(w, http.StatusBadRequest, err.Error())
		return
	}

	st, err := s.proc.Start(req.Config)
	if err != nil {
		if errors.Is(err, procctl.ErrConflict) {
			errorJSON(w, http.StatusConflict, err.Error())
			return
		}
		if errors.Is(err, procctl.ErrInvalidConfig) || errors.Is(err, procctl.ErrConfigNotFound) {
			errorJSON(w, http.StatusBadRequest, "validation failed: "+err.Error())
			return
		}
		if errors.Is(err, procctl.ErrNotSupported) {
			errorJSON(w, http.StatusNotImplemented, "not supported")
			return
		}
		errorJSON(w, http.StatusInternalServerError, "internal error: "+err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"ok": true, "running": st.Running, "pid": st.Pid, "config_path": st.ConfigPath})
}

func (s *Server) handleMediaRestart(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		errorJSON(w, http.StatusMethodNotAllowed, "method not allowed")
		return
	}
	if !s.authorize(r, true) {
		errorJSON(w, http.StatusUnauthorized, "unauthorized")
		return
	}
	if s.proc == nil || !s.proc.Enabled() {
		errorJSON(w, http.StatusNotImplemented, "not supported")
		return
	}

	req, err := readOptionalJSON[mediaProcReq](w, r, 1<<20)
	if err != nil {
		errorJSON(w, http.StatusBadRequest, err.Error())
		return
	}

	st, err := s.proc.Restart(req.Config)
	if err != nil {
		if errors.Is(err, procctl.ErrInvalidConfig) || errors.Is(err, procctl.ErrConfigNotFound) {
			errorJSON(w, http.StatusBadRequest, "validation failed: "+err.Error())
			return
		}
		if errors.Is(err, procctl.ErrNotSupported) {
			errorJSON(w, http.StatusNotImplemented, "not supported")
			return
		}
		errorJSON(w, http.StatusInternalServerError, "internal error: "+err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"ok": true, "running": st.Running, "pid": st.Pid, "config_path": st.ConfigPath})
}

func (s *Server) handleMediaStop(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		errorJSON(w, http.StatusMethodNotAllowed, "method not allowed")
		return
	}
	if !s.authorize(r, true) {
		errorJSON(w, http.StatusUnauthorized, "unauthorized")
		return
	}
	if s.proc == nil || !s.proc.Enabled() {
		errorJSON(w, http.StatusNotImplemented, "not supported")
		return
	}
	st, err := s.proc.Stop()
	if err != nil {
		if errors.Is(err, procctl.ErrNotSupported) {
			errorJSON(w, http.StatusNotImplemented, "not supported")
			return
		}
		errorJSON(w, http.StatusInternalServerError, "internal error: "+err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"ok": true, "running": st.Running, "pid": st.Pid, "config_path": st.ConfigPath})
}

func (s *Server) handleMediaStatus(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		errorJSON(w, http.StatusMethodNotAllowed, "method not allowed")
		return
	}
	if !s.authorize(r, false) {
		errorJSON(w, http.StatusUnauthorized, "unauthorized")
		return
	}
	if s.proc == nil || !s.proc.Enabled() {
		errorJSON(w, http.StatusNotImplemented, "not supported")
		return
	}
	st, err := s.proc.Status()
	if err != nil {
		if errors.Is(err, procctl.ErrNotSupported) {
			errorJSON(w, http.StatusNotImplemented, "not supported")
			return
		}
		errorJSON(w, http.StatusInternalServerError, "internal error: "+err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"ok": true, "running": st.Running, "pid": st.Pid, "config_path": st.ConfigPath})
}

func readOptionalJSON[T any](w http.ResponseWriter, r *http.Request, maxBytes int64) (T, error) {
	var zero T
	if r.Body == nil {
		return zero, nil
	}

	r.Body = http.MaxBytesReader(w, r.Body, maxBytes)
	body, err := io.ReadAll(r.Body)
	if err != nil {
		if strings.Contains(err.Error(), "request body too large") {
			return zero, errors.New("payload too large")
		}
		return zero, fmt.Errorf("invalid json: %v", err)
	}
	if len(strings.TrimSpace(string(body))) == 0 {
		return zero, nil
	}

	if mt, _, err := mime.ParseMediaType(r.Header.Get("Content-Type")); err != nil || mt != "application/json" {
		return zero, errors.New("validation failed: Content-Type must be application/json")
	}

	var v T
	if err := json.Unmarshal(body, &v); err != nil {
		return zero, fmt.Errorf("invalid json: %v", err)
	}
	return v, nil
}

func (s *Server) handleGraphs(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		errorJSON(w, http.StatusMethodNotAllowed, "method not allowed")
		return
	}
	if !s.authorize(r, false) {
		errorJSON(w, http.StatusUnauthorized, "unauthorized")
		return
	}
	st, b, err := s.ms.GetGraphs(r.Context())
	if err != nil {
		errorJSON(w, http.StatusInternalServerError, "internal error: "+err.Error())
		return
	}
	writeRawJSON(w, st, b)
}

func (s *Server) handleGraphDetail(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		errorJSON(w, http.StatusMethodNotAllowed, "method not allowed")
		return
	}
	if !s.authorize(r, false) {
		errorJSON(w, http.StatusUnauthorized, "unauthorized")
		return
	}
	name := strings.TrimPrefix(r.URL.Path, "/v1/graphs/")
	if name == "" {
		errorJSON(w, http.StatusNotFound, "not found")
		return
	}
	st, b, err := s.ms.GetGraph(r.Context(), name)
	if err != nil {
		errorJSON(w, http.StatusInternalServerError, "internal error: "+err.Error())
		return
	}
	writeRawJSON(w, st, b)
}

func (s *Server) handleLogsRecent(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		errorJSON(w, http.StatusMethodNotAllowed, "method not allowed")
		return
	}
	if !s.authorize(r, false) {
		errorJSON(w, http.StatusUnauthorized, "unauthorized")
		return
	}
	limit := 200
	if v := strings.TrimSpace(r.URL.Query().Get("limit")); v != "" {
		if n, err := strconv.Atoi(v); err == nil && n > 0 {
			limit = n
		}
	}
	st, b, err := s.ms.GetLogsRecent(r.Context(), limit)
	if err != nil {
		errorJSON(w, http.StatusInternalServerError, "internal error: "+err.Error())
		return
	}
	writeRawJSON(w, st, b)
}

func (s *Server) authorize(r *http.Request, write bool) bool {
	need := write || s.agentCfg.RequireTokenForRead
	if !need {
		return true
	}
	tok := r.Header.Get("X-RK-Token")
	return tok != "" && tok == s.agentCfg.Token
}

func writeJSON(w http.ResponseWriter, status int, v any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(v)
}

func writeRawJSON(w http.ResponseWriter, status int, raw []byte) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_, _ = w.Write(raw)
}

func errorJSON(w http.ResponseWriter, status int, msg string) {
	writeJSON(w, status, map[string]any{"error": msg})
}