package server

import (
	"io/fs"
	"net/http"
	"strings"
	"time"

	"task/internal/sqlite"
	"task/internal/syncbackend"
	"task/internal/webembed"
)

// Server is the HTTP API + embedded UI.
type Server struct {
	DB          *sqlite.DB
	Projects    *sqlite.ProjectStore
	Tickets     *sqlite.TicketStore
	Times       *sqlite.TimeStore
	Attachments *sqlite.AttachmentStore
	Sync        *syncbackend.Registry
	DataDir     string // root for on-disk attachments (cfg.DataDir)
	Secure      bool   // set Secure on cookies when behind TLS
	Static      fs.FS
}

// New constructs a server from an open DB.
func New(db *sqlite.DB) *Server {
	return &Server{
		DB:          db,
		Projects:    sqlite.NewProjectStore(db),
		Tickets:     sqlite.NewTicketStore(db),
		Times:       sqlite.NewTimeStore(db),
		Attachments: sqlite.NewAttachmentStore(db),
		Sync:        syncbackend.NewRegistry(),
		Static:      webembed.FS(),
	}
}

// Handler returns the root HTTP handler.
func (s *Server) Handler() http.Handler {
	mux := http.NewServeMux()
	s.routes(mux)
	return withCORS(mux)
}

func (s *Server) routes(mux *http.ServeMux) {
	api := http.NewServeMux()
	api.HandleFunc("GET /health", func(w http.ResponseWriter, _ *http.Request) {
		writeJSON(w, http.StatusOK, map[string]string{"status": "ok"})
	})

	api.HandleFunc("POST /auth/login", s.handleLogin)
	api.HandleFunc("POST /auth/logout", s.requireAuth(s.handleLogout))
	api.HandleFunc("GET /auth/me", s.requireAuth(s.handleMe))

	api.HandleFunc("GET /users", s.requireAdmin(s.handleListUsers))
	api.HandleFunc("POST /users", s.requireAdmin(s.handleCreateUser))
	api.HandleFunc("PATCH /users/{id}", s.requireAdmin(s.handlePatchUser))
	api.HandleFunc("DELETE /users/{id}", s.requireAdmin(s.handleDeleteUser))

	api.HandleFunc("GET /dashboard", s.requireAuth(s.handleDashboard))

	api.HandleFunc("GET /project-groups", s.requireAuth(s.handleListGroups))
	api.HandleFunc("POST /project-groups", s.requireAuth(s.handleCreateGroup))
	api.HandleFunc("PATCH /project-groups/{id}", s.requireAuth(s.handlePatchGroup))
	api.HandleFunc("DELETE /project-groups/{id}", s.requireAuth(s.handleDeleteGroup))

	api.HandleFunc("GET /projects", s.requireAuth(s.handleListProjects))
	api.HandleFunc("POST /projects", s.requireAuth(s.handleCreateProject))
	api.HandleFunc("GET /projects/{id}", s.requireAuth(s.handleGetProject))
	api.HandleFunc("PATCH /projects/{id}", s.requireAuth(s.handlePatchProject))
	api.HandleFunc("DELETE /projects/{id}", s.requireAuth(s.handleDeleteProject))

	api.HandleFunc("GET /projects/{id}/members", s.requireAuth(s.handleListMembers))
	api.HandleFunc("PUT /projects/{id}/members/{userId}", s.requireAuth(s.handleSetMember))
	api.HandleFunc("DELETE /projects/{id}/members/{userId}", s.requireAuth(s.handleRemoveMember))

	api.HandleFunc("GET /projects/{id}/tokens", s.requireAuth(s.handleListTokens))
	api.HandleFunc("POST /projects/{id}/tokens", s.requireAuth(s.handleCreateToken))
	api.HandleFunc("DELETE /projects/{id}/tokens/{tid}", s.requireAuth(s.handleRevokeToken))

	api.HandleFunc("GET /projects/{id}/sync", s.requireAuth(s.handleGetSync))
	api.HandleFunc("PUT /projects/{id}/sync", s.requireAuth(s.handlePutSync))
	api.HandleFunc("POST /projects/{id}/sync/pull", s.requireAuth(s.handleSyncPull))
	api.HandleFunc("POST /projects/{id}/sync/push", s.requireAuth(s.handleSyncPush))

	api.HandleFunc("GET /projects/{id}/tickets", s.requireAuth(s.handleListTickets))
	api.HandleFunc("POST /projects/{id}/tickets", s.requireAuth(s.handleCreateTicket))
	api.HandleFunc("GET /projects/{id}/tickets/{tid}", s.requireAuth(s.handleGetTicket))
	api.HandleFunc("PATCH /projects/{id}/tickets/{tid}", s.requireAuth(s.handlePatchTicket))
	api.HandleFunc("DELETE /projects/{id}/tickets/{tid}", s.requireAuth(s.handleDeleteTicket))
	api.HandleFunc("POST /projects/{id}/tickets/{tid}/move", s.requireAuth(s.handleMoveTicket))

	api.HandleFunc("GET /projects/{id}/tickets/{tid}/attachments", s.requireAuth(s.handleListAttachments))
	api.HandleFunc("POST /projects/{id}/tickets/{tid}/attachments", s.requireAuth(s.handleUploadAttachment))
	api.HandleFunc("GET /projects/{id}/tickets/{tid}/attachments/{aid}", s.requireAuth(s.handleGetAttachment))
	api.HandleFunc("PUT /projects/{id}/tickets/{tid}/attachments/{aid}", s.requireAuth(s.handlePutAttachment))
	api.HandleFunc("DELETE /projects/{id}/tickets/{tid}/attachments/{aid}", s.requireAuth(s.handleDeleteAttachment))

	api.HandleFunc("GET /projects/{id}/tickets/{tid}/revisions", s.requireAuth(s.handleListTicketRevisions))
	api.HandleFunc("POST /projects/{id}/tickets/{tid}/revisions/{rid}/restore", s.requireAuth(s.handleRestoreTicketRevision))

	api.HandleFunc("GET /projects/{id}/report", s.requireAuth(s.handleProjectReport))
	api.HandleFunc("GET /projects/{id}/time", s.requireAuth(s.handleListProjectTime))
	api.HandleFunc("POST /projects/{id}/time", s.requireAuth(s.handleCreateTime))
	api.HandleFunc("PATCH /projects/{id}/time/{eid}", s.requireAuth(s.handleUpdateTime))
	api.HandleFunc("DELETE /projects/{id}/time/{eid}", s.requireAuth(s.handleDeleteTime))
	api.HandleFunc("GET /timer", s.requireAuth(s.handleGetTimer))
	api.HandleFunc("POST /timer/start", s.requireAuth(s.handleStartTimer))
	api.HandleFunc("POST /timer/stop", s.requireAuth(s.handleStopTimer))

	api.HandleFunc("GET /connections", s.requireAdmin(s.handleListConnections))
	api.HandleFunc("POST /connections", s.requireAdmin(s.handleCreateConnection))
	api.HandleFunc("DELETE /connections/{id}", s.requireAdmin(s.handleDeleteConnection))
	api.HandleFunc("GET /connections/{id}/projects", s.requireAdmin(s.handleConnectionProjects))
	api.HandleFunc("POST /connections/{id}/import", s.requireAdmin(s.handleImportProject))

	mux.Handle("/api/v1/", http.StripPrefix("/api/v1", api))
	mux.Handle("/", s.spaHandler())
}

const sessionCookie = "tm_session"

func (s *Server) setSessionCookie(w http.ResponseWriter, token string, expires time.Time) {
	http.SetCookie(w, &http.Cookie{
		Name:     sessionCookie,
		Value:    token,
		Path:     "/",
		HttpOnly: true,
		SameSite: http.SameSiteLaxMode,
		Secure:   s.Secure,
		Expires:  expires,
	})
}

func (s *Server) clearSessionCookie(w http.ResponseWriter) {
	http.SetCookie(w, &http.Cookie{
		Name:     sessionCookie,
		Value:    "",
		Path:     "/",
		HttpOnly: true,
		SameSite: http.SameSiteLaxMode,
		Secure:   s.Secure,
		MaxAge:   -1,
		Expires:  time.Unix(0, 0),
	})
}

func withCORS(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		origin := r.Header.Get("Origin")
		if origin != "" {
			w.Header().Set("Access-Control-Allow-Origin", origin)
			w.Header().Set("Access-Control-Allow-Credentials", "true")
			w.Header().Set("Access-Control-Allow-Headers", "Content-Type")
			w.Header().Set("Access-Control-Allow-Methods", "GET,POST,PUT,PATCH,DELETE,OPTIONS")
		}
		if r.Method == http.MethodOptions {
			w.WriteHeader(http.StatusNoContent)
			return
		}
		next.ServeHTTP(w, r)
	})
}

func (s *Server) spaHandler() http.Handler {
	static := s.Static
	if static == nil {
		static = webembed.FS()
	}
	fileServer := http.FileServer(http.FS(static))
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		path := strings.TrimPrefix(r.URL.Path, "/")
		if path == "" {
			path = "index.html"
		}
		if f, err := static.Open(path); err == nil {
			_ = f.Close()
			fileServer.ServeHTTP(w, r)
			return
		}
		// SPA fallback
		r2 := r.Clone(r.Context())
		r2.URL.Path = "/index.html"
		fileServer.ServeHTTP(w, r2)
	})
}