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"
	"github.com/sandrodach/mindsift/internal/storage"
)

func (s *Server) handleCaptureInbox(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	var req struct {
		Content      string `json:"content"`
		Priority     string `json:"priority"`
		Source       string `json:"source"`
		DueDate      string `json:"dueDate"`
		DueDate2     string `json:"due_date"`
		Target       string `json:"target"` // inbox | task | list_item | document
		TargetListID string `json:"targetListId"`
		TargetList2  string `json:"target_list_id"`
		TaskListID   string `json:"taskListId"`
		TaskListID2  string `json:"task_list_id"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "Ungültiges JSON")
		return
	}
	dueDate := req.DueDate
	if dueDate == "" {
		dueDate = req.DueDate2
	}
	targetListID := req.TargetListID
	if targetListID == "" {
		targetListID = req.TargetList2
	}
	taskListID := req.TaskListID
	if taskListID == "" {
		taskListID = req.TaskListID2
	}

	source := strings.ToLower(strings.TrimSpace(req.Source))
	if source == "" {
		source = strings.ToLower(strings.TrimSpace(r.URL.Query().Get("source")))
	}
	if source == "" {
		source = strings.ToLower(strings.TrimSpace(r.Header.Get("X-Source")))
	}
	if source == "" {
		// When called via API key or webhook token, automatically default source to "webhook"
		if r.Header.Get("X-API-Key") != "" ||
			strings.HasPrefix(r.Header.Get("Authorization"), "Bearer mindsift_sec_") ||
			strings.HasPrefix(r.URL.Query().Get("token"), "mindsift_sec_") {
			source = "webhook"
		} else {
			source = "manual"
		}
	}

	thought, err := s.store.CreateThoughtWithDetails(userID, req.Content, req.Priority, source, dueDate, taskListID, "todo", "")
	if err != nil {
		writeStoreError(w, http.StatusBadRequest, err)
		return
	}

	target := strings.TrimSpace(req.Target)
	if target == "task" || target == "document" || (target == "list_item" && targetListID != "") {
		if converted, convErr := s.store.UpdateThoughtTriage(userID, thought.ID, "keep", target, targetListID, dueDate, taskListID); convErr == nil && converted != nil {
			thought = converted
			if target == "list_item" && targetListID != "" {
				if lst, lErr := s.store.GetListByID(userID, targetListID); lErr == nil && lst != nil {
					s.wsHub.BroadcastListEvent(lst.ID, "LIST_UPDATED", lst)
				}
			}
		}
	}

	s.wsHub.BroadcastToUsers(s.taskAudience(thought), "TASK_CREATED", thought)
	writeJSON(w, http.StatusCreated, thought)
}

func (s *Server) handleGetThoughts(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	status := r.URL.Query().Get("status")
	thoughts, err := s.store.GetThoughts(userID, status, 250)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, thoughts)
}

func (s *Server) handleGetThought(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	thoughtID := chi.URLParam(r, "id")
	thought, err := s.store.GetThoughtByID(userID, thoughtID)
	if err != nil || thought == nil {
		writeError(w, http.StatusNotFound, "Aufgabe nicht gefunden")
		return
	}
	writeJSON(w, http.StatusOK, thought)
}

func (s *Server) handleGetTriageDeck(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	thoughts, err := s.store.GetThoughts(userID, "inbox", 100)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, thoughts)
}

func (s *Server) handleTriageAction(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	thoughtID := chi.URLParam(r, "id")

	var req struct {
		Action       string `json:"action"` // keep | discard | restore
		ConvertTo    string `json:"convertTo"`
		ConvertTo2   string `json:"convert_to"`
		TargetListID string `json:"targetListId"`
		TargetList2  string `json:"target_list_id"`
		TaskListID   string `json:"taskListId"`
		TaskListID2  string `json:"task_list_id"`
		DueDate      string `json:"dueDate"`
		DueDate2     string `json:"due_date"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "Ungültiges JSON")
		return
	}

	convertTo := req.ConvertTo
	if convertTo == "" {
		convertTo = req.ConvertTo2
	}
	targetListID := req.TargetListID
	if targetListID == "" {
		targetListID = req.TargetList2
	}
	taskListID := req.TaskListID
	if taskListID == "" {
		taskListID = req.TaskListID2
	}
	dueDate := req.DueDate
	if dueDate == "" {
		dueDate = req.DueDate2
	}

	updated, err := s.store.UpdateThoughtTriage(userID, thoughtID, req.Action, convertTo, targetListID, dueDate, taskListID)
	if err != nil {
		writeStoreError(w, http.StatusBadRequest, err)
		return
	}

	// If converted to a list item, broadcast via WebSocket to the space
	if convertTo == "list_item" && targetListID != "" {
		if lst, err := s.store.GetListByID(userID, targetListID); err == nil && lst != nil {
			s.wsHub.BroadcastListEvent(lst.ID, "LIST_UPDATED", lst)
		}
	}

	s.wsHub.BroadcastToUsers(s.taskAudience(updated), "TASK_UPDATED", updated)
	writeJSON(w, http.StatusOK, updated)
}

func (s *Server) handleGetTasks(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	taskListID := r.URL.Query().Get("taskListId")
	tasks, err := s.store.GetTasks(userID, taskListID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, tasks)
}

func (s *Server) handleReorderTasks(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	taskListID := chi.URLParam(r, "id")
	if taskListID == "" {
		taskListID = r.URL.Query().Get("taskListId")
	}

	var req struct {
		Items []domain.ThoughtReorderItem `json:"items"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "Ungültiges JSON")
		return
	}

	if taskListID != "" && !s.store.CanEditTaskList(userID, taskListID) {
		writeError(w, http.StatusForbidden, storage.ErrTaskListReadOnly.Error())
		return
	}
	// ReorderTasks updates by ID only, so every item must be a task the caller may edit
	audience := []string{userID}
	for _, it := range req.Items {
		th, err := s.store.GetThoughtByID(userID, it.ID)
		if err != nil {
			writeError(w, http.StatusNotFound, "Aufgabe nicht gefunden")
			return
		}
		if th.TaskListID != "" && !s.store.CanEditTaskList(userID, th.TaskListID) {
			writeError(w, http.StatusForbidden, storage.ErrTaskListReadOnly.Error())
			return
		}
		audience = append(audience, s.taskAudience(th)...)
	}

	if err := s.store.ReorderTasks(taskListID, req.Items); err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	s.wsHub.BroadcastToUsers(audience, "TASK_REORDERED", map[string]interface{}{
		"taskListId": taskListID,
		"items":      req.Items,
		"userId":     userID,
	})
	writeJSON(w, http.StatusOK, map[string]bool{"success": true})
}

func (s *Server) handleUpdateThought(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	thoughtID := chi.URLParam(r, "id")

	var req struct {
		Content      *string           `json:"content"`
		IsCompleted  *bool             `json:"isCompleted"`
		DueDate      *string           `json:"dueDate"`
		Priority     *string           `json:"priority"`
		TaskListID   *string           `json:"taskListId"`
		KanbanStatus *string           `json:"kanbanStatus"`
		Notes        *string           `json:"notes"`
		Subtasks     *[]domain.SubTask `json:"subtasks"`
		Tags         *[]string         `json:"tags"`
		Assignees    *[]string         `json:"assignees"`
		Recurrence   *string           `json:"recurrence"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "Ungültiges JSON")
		return
	}

	before, _ := s.store.GetThoughtByID(userID, thoughtID)
	// The rule is set first, so completing a task in the same request already repeats it
	if req.Recurrence != nil {
		if err := s.store.SetTaskRecurrence(userID, thoughtID, strings.TrimSpace(*req.Recurrence)); err != nil {
			writeStoreError(w, http.StatusBadRequest, err)
			return
		}
	}
	updated, err := s.store.UpdateThoughtDetails(userID, thoughtID, req.Content, req.IsCompleted, req.DueDate, req.Priority, req.TaskListID, req.KanbanStatus, req.Notes, req.Subtasks, req.Tags)
	if err != nil {
		writeStoreError(w, http.StatusBadRequest, err)
		return
	}
	if req.Assignees != nil {
		assignees, err := s.store.SetTaskAssignees(userID, thoughtID, *req.Assignees)
		if err != nil {
			writeStoreError(w, http.StatusBadRequest, err)
			return
		}
		updated.Assignees = assignees
	}
	if docID := s.store.SyncDocBlockAndTask(userID, thoughtID, updated.IsCompleted); docID != "" {
		_, head, _ := s.store.GetDocOpsSince(docID, 0, 0)
		s.notifyDocChanged(docID, head)
	}
	s.wsHub.BroadcastToUsers(append(s.taskAudience(before), s.taskAudience(updated)...), "TASK_UPDATED", updated)
	writeJSON(w, http.StatusOK, updated)
}

func (s *Server) handleUnlinkEnhancedTask(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	thoughtID := chi.URLParam(r, "id")
	s.store.UnlinkTaskFromDocBlock(userID, thoughtID)
	writeJSON(w, http.StatusOK, map[string]bool{"unlinked": true})
}

func (s *Server) handleDeleteThought(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	thoughtID := chi.URLParam(r, "id")
	th, err := s.store.GetThoughtByID(userID, thoughtID)
	if err == nil && th.TaskListID != "" && !s.store.CanEditTaskList(userID, th.TaskListID) {
		writeError(w, http.StatusForbidden, storage.ErrTaskListReadOnly.Error())
		return
	}
	audience := s.taskAudience(th)
	s.store.UnlinkTaskFromDocBlock(userID, thoughtID)
	if err := s.store.DeleteThought(userID, thoughtID); err != nil {
		writeStoreError(w, http.StatusInternalServerError, err)
		return
	}
	s.wsHub.BroadcastToUsers(audience, "TASK_DELETED", map[string]string{"id": thoughtID})
	writeJSON(w, http.StatusOK, map[string]bool{"deleted": true})
}

func (s *Server) handlePurgeDiscarded(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	count, err := s.store.PurgeDiscardedThoughts(userID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]int64{"purged": count})
}

// --- SEARCH & EXPORT ---

func (s *Server) handleSearch(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r.Context())
	q := r.URL.Query().Get("q")
	res, err := s.store.SearchGlobal(userID, q)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, res)
}