package gui

import (
	"encoding/json"
	"fmt"
	"html/template"
	"log"
	"net"
	"net/http"
	"strings"

	"verstak/internal/core/files"
	"verstak/internal/core/notes"
	"verstak/internal/core/nodes"
	"verstak/internal/core/storage"
)

// Server is the GUI HTTP server bound to a vault.
type Server struct {
	db        *storage.DB
	vaultRoot string
	nodes     *nodes.Repository
	files     *files.Service
	notes     *notes.Service
	srv       *http.Server
	listener  net.Listener
	port      int
}

// NewServer creates a GUI server for the given vault.
func NewServer(db *storage.DB, vaultRoot string) *Server {
	nodeRepo := nodes.NewRepository(db)
	fileSvc := files.NewService(db, vaultRoot)
	noteSvc := notes.NewService(db, vaultRoot, nodeRepo, fileSvc)
	return &Server{
		db: db, vaultRoot: vaultRoot,
		nodes: nodeRepo, files: fileSvc, notes: noteSvc,
	}
}

// Start binds on a free port and returns the base URL.
func (s *Server) Start() (string, error) {
	mux := http.NewServeMux()
	mux.HandleFunc("/api/nodes", s.handleNodes)
	mux.HandleFunc("/api/nodes/", s.handleNodeDetail)
	mux.HandleFunc("/api/notes/", s.handleNotes)
	mux.HandleFunc("/api/files/", s.handleFiles)
	mux.HandleFunc("/api/search", s.handleSearch)
	mux.HandleFunc("/", s.handleStatic)

	s.srv = &http.Server{Handler: mux}
	ln, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		return "", err
	}
	s.listener = ln
	s.port = ln.Addr().(*net.TCPAddr).Port
	go func() {
		if e := s.srv.Serve(ln); e != nil && e != http.ErrServerClosed {
			log.Printf("GUI: %v", e)
		}
	}()
	return fmt.Sprintf("http://127.0.0.1:%d", s.port), nil
}

// Stop shuts down the server.
func (s *Server) Stop() error {
	if s.srv != nil {
		return s.srv.Close()
	}
	return nil
}

// Addr returns the base URL.
func (s *Server) Addr() string {
	return fmt.Sprintf("http://127.0.0.1:%d", s.port)
}

// --- handlers ---

func (s *Server) handleStatic(w http.ResponseWriter, r *http.Request) {
	if r.URL.Path != "/" && r.URL.Path != "/index.html" {
		http.NotFound(w, r)
		return
	}
	t := template.Must(template.New("idx").Parse(indexHTML))
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	t.Execute(w, nil)
}

func jsonOK(w http.ResponseWriter, v interface{}) {
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(v)
}

func jsonErr(w http.ResponseWriter, code int, msg string) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(code)
	json.NewEncoder(w).Encode(map[string]string{"error": msg})
}

// GET /api/nodes[?parent=ID]  POST /api/nodes
func (s *Server) handleNodes(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case "GET":
		parent := r.URL.Query().Get("parent")
		var list interface{}
		var err error
		if parent == "" {
			list, err = s.nodes.ListRoots(false)
		} else {
			list, err = s.nodes.ListChildren(parent, false)
		}
		if err != nil {
			jsonErr(w, 500, err.Error())
			return
		}
		jsonOK(w, list)
	case "POST":
		var req struct {
			ParentID string `json:"parent_id"`
			Type     string `json:"type"`
			Title    string `json:"title"`
		}
		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
			jsonErr(w, 400, "bad json")
			return
		}
		n, err := s.nodes.Create(req.ParentID, req.Type, req.Title)
		if err != nil {
			jsonErr(w, 500, err.Error())
			return
		}
		jsonOK(w, n)
	default:
		jsonErr(w, 405, "method not allowed")
	}
}

// GET/PUT/DELETE /api/nodes/{id}
func (s *Server) handleNodeDetail(w http.ResponseWriter, r *http.Request) {
	id := strings.TrimPrefix(r.URL.Path, "/api/nodes/")
	switch r.Method {
	case "GET":
		n, err := s.nodes.GetActive(id)
		if err != nil {
			jsonErr(w, 404, "not found")
			return
		}
		children, _ := s.nodes.ListChildren(id, false)
		fl, _ := s.files.ListByNode(id)
		meta, _ := s.nodes.MetaList(id)
		jsonOK(w, map[string]interface{}{
			"node": n, "children": children, "files": fl, "meta": meta,
		})
	case "PUT":
		var req struct {
			Title    string `json:"title"`
			ParentID string `json:"parent_id"`
			Sort     int    `json:"sort_order"`
		}
		json.NewDecoder(r.Body).Decode(&req)
		if req.Title != "" {
			s.nodes.UpdateTitle(id, req.Title)
		}
		if req.ParentID != "" {
			s.nodes.Move(id, req.ParentID, req.Sort)
		}
		jsonOK(w, map[string]string{"status": "ok"})
	case "DELETE":
		s.nodes.SoftDelete(id)
		jsonOK(w, map[string]string{"status": "deleted"})
	default:
		jsonErr(w, 405, "method not allowed")
	}
}

// POST /api/notes/{parentID}  PUT/GET /api/notes/{nodeID}
func (s *Server) handleNotes(w http.ResponseWriter, r *http.Request) {
	path := strings.TrimPrefix(r.URL.Path, "/api/notes/")
	switch r.Method {
	case "GET":
		rec, err := s.notes.Load(path)
		if err != nil {
			jsonErr(w, 404, "not found")
			return
		}
		content, _ := s.notes.Read(path)
		jsonOK(w, map[string]interface{}{"record": rec, "content": content})
	case "POST":
		var req struct{ Title string `json:"title"` }
		json.NewDecoder(r.Body).Decode(&req)
		n, _, err := s.notes.Create(path, req.Title)
		if err != nil {
			jsonErr(w, 500, err.Error())
			return
		}
		jsonOK(w, n)
	case "PUT":
		var req struct{ Content string `json:"content"` }
		json.NewDecoder(r.Body).Decode(&req)
		if err := s.notes.Save(path, req.Content); err != nil {
			jsonErr(w, 500, err.Error())
			return
		}
		jsonOK(w, map[string]string{"status": "saved"})
	default:
		jsonErr(w, 405, "method not allowed")
	}
}

// GET/DELETE /api/files/{id}
func (s *Server) handleFiles(w http.ResponseWriter, r *http.Request) {
	id := strings.TrimPrefix(r.URL.Path, "/api/files/")
	switch r.Method {
	case "GET":
		rec, err := s.files.Get(id)
		if err != nil {
			jsonErr(w, 404, err.Error())
			return
		}
		jsonOK(w, rec)
	case "DELETE":
		if err := s.files.DeleteToTrash(id); err != nil {
			jsonErr(w, 500, err.Error())
			return
		}
		jsonOK(w, map[string]string{"status": "trashed"})
	default:
		jsonErr(w, 405, "method not allowed")
	}
}

// GET /api/search?q=...
func (s *Server) handleSearch(w http.ResponseWriter, r *http.Request) {
	q := strings.ToLower(r.URL.Query().Get("q"))
	if len(q) < 2 {
		jsonOK(w, []interface{}{})
		return
	}
	roots, _ := s.nodes.ListRoots(false)
	var hits []map[string]interface{}
	for _, n := range roots {
		if strings.Contains(strings.ToLower(n.Title), q) {
			hits = append(hits, map[string]interface{}{"id": n.ID, "title": n.Title, "type": n.Type})
		}
	}
	jsonOK(w, hits)
}