package devices

import (
	"encoding/json"
	"net/http"
	"strings"

	"github.com/go-chi/chi/v5"
	"github.com/wangjia/pangolin/server/internal/apierr"
	"github.com/wangjia/pangolin/server/internal/auth"
)

// Handler serves the account device endpoints. It assumes the JWT auth
// middleware (module #2) has set CtxKeyUserID on the request context.
type Handler struct {
	svc *Service
}

// NewHandler creates a Handler backed by svc.
func NewHandler(svc *Service) *Handler { return &Handler{svc: svc} }

// RegisterRoutes mounts the device routes on r under the caller's chosen prefix
// (the API mounts these beneath /v1/me):
//
//	GET    /devices
//	DELETE /devices/{id}
//	POST   /devices/{id}/logout
func (h *Handler) RegisterRoutes(r chi.Router) {
	r.Get("/devices", h.ListDevices)
	r.Delete("/devices/{id}", h.DeleteDevice)
	r.Post("/devices/{id}/logout", h.ForceLogout)
	r.Post("/devices/{id}/rename", h.RenameDevice)
	r.Get("/session", h.SessionCheck) // GET /v1/me/session?device_id= — 会话有效性轮询
}

type listDevicesResponse struct {
	Devices []Device `json:"devices"`
}

// ListDevices handles GET /v1/me/devices.
func (h *Handler) ListDevices(w http.ResponseWriter, r *http.Request) {
	userID, ok := auth.UserIDFromContext(r.Context())
	if !ok {
		apierr.WriteJSON(w, http.StatusUnauthorized, apierr.ErrUnauthorized)
		return
	}

	devices, apiErr := h.svc.ListDevices(r.Context(), userID)
	if apiErr != nil {
		apierr.WriteJSON(w, StatusForError(apiErr), apiErr)
		return
	}

	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(http.StatusOK)
	_ = json.NewEncoder(w).Encode(listDevicesResponse{Devices: devices})
}

// DeleteDevice handles DELETE /v1/me/devices/{id}.
func (h *Handler) DeleteDevice(w http.ResponseWriter, r *http.Request) {
	userID, ok := auth.UserIDFromContext(r.Context())
	if !ok {
		apierr.WriteJSON(w, http.StatusUnauthorized, apierr.ErrUnauthorized)
		return
	}

	deviceUUID := chi.URLParam(r, "id")
	if apiErr := h.svc.DeleteDevice(r.Context(), userID, deviceUUID); apiErr != nil {
		apierr.WriteJSON(w, StatusForError(apiErr), apiErr)
		return
	}

	w.WriteHeader(http.StatusNoContent)
}

// ForceLogout handles POST /v1/me/devices/{id}/logout — revoke the device's
// sessions (kick it offline); the device stays in the list.
func (h *Handler) ForceLogout(w http.ResponseWriter, r *http.Request) {
	userID, ok := auth.UserIDFromContext(r.Context())
	if !ok {
		apierr.WriteJSON(w, http.StatusUnauthorized, apierr.ErrUnauthorized)
		return
	}

	deviceUUID := chi.URLParam(r, "id")
	if apiErr := h.svc.ForceLogout(r.Context(), userID, deviceUUID); apiErr != nil {
		apierr.WriteJSON(w, StatusForError(apiErr), apiErr)
		return
	}

	w.WriteHeader(http.StatusNoContent)
}

// SessionCheck handles GET /v1/me/session?device_id=UUID — reports whether the
// caller's device still has a live session. false ⇒ force-logged-out elsewhere;
// the client polls this (~15s) and logs out on {"active":false} → near-instant kick.
// Always 200 (the verdict is in the body); device_id 取自 query。
func (h *Handler) SessionCheck(w http.ResponseWriter, r *http.Request) {
	userID, ok := auth.UserIDFromContext(r.Context())
	if !ok {
		apierr.WriteJSON(w, http.StatusUnauthorized, apierr.ErrUnauthorized)
		return
	}
	deviceUUID := strings.TrimSpace(r.URL.Query().Get("device_id"))
	active, apiErr := h.svc.SessionActive(r.Context(), userID, deviceUUID)
	if apiErr != nil {
		apierr.WriteJSON(w, StatusForError(apiErr), apiErr)
		return
	}
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(http.StatusOK)
	_ = json.NewEncoder(w).Encode(map[string]bool{"active": active})
}

// RenameDevice handles POST /v1/me/devices/{id}/rename — set a device's name.
func (h *Handler) RenameDevice(w http.ResponseWriter, r *http.Request) {
	userID, ok := auth.UserIDFromContext(r.Context())
	if !ok {
		apierr.WriteJSON(w, http.StatusUnauthorized, apierr.ErrUnauthorized)
		return
	}
	var req struct {
		Name string `json:"name"`
	}
	if err := json.NewDecoder(http.MaxBytesReader(w, r.Body, 1<<14)).Decode(&req); err != nil {
		apierr.WriteJSON(w, http.StatusBadRequest, apierr.ErrBadRequest)
		return
	}
	deviceUUID := chi.URLParam(r, "id")
	if apiErr := h.svc.RenameDevice(r.Context(), userID, deviceUUID, req.Name); apiErr != nil {
		apierr.WriteJSON(w, StatusForError(apiErr), apiErr)
		return
	}
	w.WriteHeader(http.StatusNoContent)
}