package api

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

	"github.com/go-chi/chi/v5"
	"github.com/sandrodach/mindsift/internal/auth"
	"github.com/sandrodach/mindsift/internal/domain"
)

// --- TASK LISTS ---

func (s *Server) handleGetTaskLists(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	lists, err := s.store.GetTaskLists(userID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, lists)
}

func (s *Server) handleCreateTaskList(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	var req struct {
		SpaceID string `json:"spaceId"`
		TeamID  string `json:"teamId"`
		Title   string `json:"title"`
		Icon    string `json:"icon"`
		Color   string `json:"color"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "Ungültiges JSON")
		return
	}
	tl, err := s.store.CreateTaskList(userID, req.SpaceID, req.TeamID, req.Title, req.Icon, req.Color)
	if err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	writeJSON(w, http.StatusCreated, tl)
}

func (s *Server) handleUpdateTaskList(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	listID := chi.URLParam(r, "id")
	var req struct {
		Title   *string                `json:"title"`
		Icon    *string                `json:"icon"`
		Color   *string                `json:"color"`
		SpaceID *string                `json:"spaceId"`
		Columns *[]domain.KanbanColumn `json:"columns"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "Ungültiges JSON")
		return
	}
	audienceBefore := s.store.GetTaskListUserIDs(listID)
	tl, err := s.store.UpdateTaskList(userID, listID, req.Title, req.Icon, req.Color, req.SpaceID, req.Columns)
	if err != nil {
		writeStoreError(w, http.StatusBadRequest, err)
		return
	}
	s.broadcastTaskListChange(listID, audienceBefore, "TASK_LIST_UPDATED")
	writeJSON(w, http.StatusOK, tl)
}

func (s *Server) handleDeleteTaskList(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	listID := chi.URLParam(r, "id")
	audienceBefore := s.store.GetTaskListUserIDs(listID)
	if err := s.store.DeleteTaskList(userID, listID); err != nil {
		writeError(w, http.StatusNotFound, err.Error())
		return
	}
	s.broadcastTaskListChange(listID, audienceBefore, "TASK_LIST_DELETED")
	writeJSON(w, http.StatusOK, map[string]bool{"deleted": true})
}

func (s *Server) handleGetTaskListShares(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	listID := chi.URLParam(r, "id")
	if _, err := s.store.GetTaskListByID(userID, listID); err != nil {
		writeError(w, http.StatusNotFound, "Aufgabenliste nicht gefunden oder kein Zugriff")
		return
	}
	shares, err := s.store.GetTaskListShares(listID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, shares)
}

func (s *Server) handleCreateTaskListShare(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	listID := chi.URLParam(r, "id")
	tl, err := s.store.GetTaskListByID(userID, listID)
	if err != nil || tl == nil {
		writeError(w, http.StatusNotFound, "Aufgabenliste nicht gefunden")
		return
	}
	if tl.UserID != userID {
		writeError(w, http.StatusForbidden, "Nur der Eigentümer kann die Liste freigeben")
		return
	}
	var req struct {
		TargetType string `json:"targetType"` // team | user
		TargetID   string `json:"targetId"`
		Permission string `json:"permission"` // editor | viewer
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "Ungültiges JSON")
		return
	}
	permission := strings.ToLower(strings.TrimSpace(req.Permission))
	if permission != "viewer" {
		permission = "editor"
	}
	share, err := s.store.AddTaskListShare(listID, req.TargetType, req.TargetID, permission, userID)
	if err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	s.broadcastTaskListChange(listID, nil, "TASK_LIST_UPDATED")
	if tl, err := s.store.GetTaskListByID(userID, listID); err == nil {
		s.notifyShared(userID, req.TargetType, req.TargetID, "die Aufgabenliste", tl.Title)
	}
	writeJSON(w, http.StatusCreated, share)
}

func (s *Server) handleDeleteTaskListShare(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	listID := chi.URLParam(r, "id")
	shareID := chi.URLParam(r, "shareId")
	tl, err := s.store.GetTaskListByID(userID, listID)
	if err != nil || tl == nil {
		writeError(w, http.StatusNotFound, "Aufgabenliste nicht gefunden")
		return
	}
	if tl.UserID != userID {
		writeError(w, http.StatusForbidden, "Nur der Eigentümer kann Freigaben entfernen")
		return
	}
	audienceBefore := s.store.GetTaskListUserIDs(listID)
	if err := s.store.RemoveTaskListShare(listID, shareID); err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	s.broadcastTaskListChange(listID, audienceBefore, "TASK_LIST_UPDATED")
	writeJSON(w, http.StatusOK, map[string]bool{"deleted": true})
}

// broadcastTaskListChange notifies everyone who could see the list before or can see it now. Only the ID is sent,
// because the list payload depends on the receiver's permission; clients reload their lists.
func (s *Server) broadcastTaskListChange(listID string, audienceBefore []string, event string) {
	users := append(audienceBefore, s.store.GetTaskListUserIDs(listID)...)
	s.wsHub.BroadcastToUsers(users, event, map[string]string{"id": listID})
}