package handlers

import (
	"context"
	"encoding/json"
	"html/template"
	"log"
	"net/http"
	"sync"
	"time"

	"task-dashboard/internal/api"
	"task-dashboard/internal/config"
	"task-dashboard/internal/models"
	"task-dashboard/internal/store"
)

// Handler holds dependencies for HTTP handlers
type Handler struct {
	store           *store.Store
	todoistClient   api.TodoistAPI
	trelloClient    api.TrelloAPI
	obsidianClient  api.ObsidianAPI
	planToEatClient api.PlanToEatAPI
	config          *config.Config
	templates       *template.Template
}

// New creates a new Handler instance
func New(store *store.Store, todoist api.TodoistAPI, trello api.TrelloAPI, obsidian api.ObsidianAPI, planToEat api.PlanToEatAPI, cfg *config.Config) *Handler {
	// Parse templates
	tmpl, err := template.ParseGlob("web/templates/*.html")
	if err != nil {
		log.Printf("Warning: failed to parse templates: %v", err)
	}

	return &Handler{
		store:           store,
		todoistClient:   todoist,
		trelloClient:    trello,
		obsidianClient:  obsidian,
		planToEatClient: planToEat,
		config:          cfg,
		templates:       tmpl,
	}
}

// HandleDashboard renders the main dashboard view
func (h *Handler) HandleDashboard(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()

	// Aggregate data from all sources
	data, err := h.aggregateData(ctx, false)
	if err != nil {
		http.Error(w, "Failed to load dashboard data", http.StatusInternalServerError)
		log.Printf("Error aggregating data: %v", err)
		return
	}

	// Render template
	if h.templates == nil {
		http.Error(w, "Templates not loaded", http.StatusInternalServerError)
		return
	}

	if err := h.templates.ExecuteTemplate(w, "index.html", data); err != nil {
		http.Error(w, "Failed to render template", http.StatusInternalServerError)
		log.Printf("Error rendering template: %v", err)
	}
}

// HandleRefresh forces a refresh of all data
func (h *Handler) HandleRefresh(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()

	// Force refresh by passing true
	data, err := h.aggregateData(ctx, true)
	if err != nil {
		http.Error(w, "Failed to refresh data", http.StatusInternalServerError)
		log.Printf("Error refreshing data: %v", err)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(data)
}

// HandleGetTasks returns tasks as JSON
func (h *Handler) HandleGetTasks(w http.ResponseWriter, r *http.Request) {
	tasks, err := h.store.GetTasks()
	if err != nil {
		http.Error(w, "Failed to get tasks", http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(tasks)
}

// HandleGetNotes returns notes as JSON
func (h *Handler) HandleGetNotes(w http.ResponseWriter, r *http.Request) {
	notes, err := h.store.GetNotes(20)
	if err != nil {
		http.Error(w, "Failed to get notes", http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(notes)
}

// HandleGetMeals returns meals as JSON
func (h *Handler) HandleGetMeals(w http.ResponseWriter, r *http.Request) {
	startDate := time.Now()
	endDate := startDate.AddDate(0, 0, 7)

	meals, err := h.store.GetMeals(startDate, endDate)
	if err != nil {
		http.Error(w, "Failed to get meals", http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(meals)
}

// HandleGetBoards returns Trello boards with cards as JSON
func (h *Handler) HandleGetBoards(w http.ResponseWriter, r *http.Request) {
	boards, err := h.store.GetBoards()
	if err != nil {
		http.Error(w, "Failed to get boards", http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(boards)
}

// aggregateData fetches and caches data from all sources
func (h *Handler) aggregateData(ctx context.Context, forceRefresh bool) (*models.DashboardData, error) {
	data := &models.DashboardData{
		LastUpdated: time.Now(),
		Errors:      make([]string, 0),
	}

	var wg sync.WaitGroup
	var mu sync.Mutex

	// Fetch Trello boards (PRIORITY - most important)
	wg.Add(1)
	go func() {
		defer wg.Done()
		boards, err := h.fetchBoards(ctx, forceRefresh)
		mu.Lock()
		defer mu.Unlock()
		if err != nil {
			data.Errors = append(data.Errors, "Trello: "+err.Error())
		} else {
			data.Boards = boards
		}
	}()

	// Fetch Todoist tasks
	wg.Add(1)
	go func() {
		defer wg.Done()
		tasks, err := h.fetchTasks(ctx, forceRefresh)
		mu.Lock()
		defer mu.Unlock()
		if err != nil {
			data.Errors = append(data.Errors, "Todoist: "+err.Error())
		} else {
			data.Tasks = tasks
		}
	}()

	// Fetch Obsidian notes (if configured)
	if h.obsidianClient != nil {
		wg.Add(1)
		go func() {
			defer wg.Done()
			notes, err := h.fetchNotes(ctx, forceRefresh)
			mu.Lock()
			defer mu.Unlock()
			if err != nil {
				data.Errors = append(data.Errors, "Obsidian: "+err.Error())
			} else {
				data.Notes = notes
			}
		}()
	}

	// Fetch PlanToEat meals (if configured)
	if h.planToEatClient != nil {
		wg.Add(1)
		go func() {
			defer wg.Done()
			meals, err := h.fetchMeals(ctx, forceRefresh)
			mu.Lock()
			defer mu.Unlock()
			if err != nil {
				data.Errors = append(data.Errors, "PlanToEat: "+err.Error())
			} else {
				data.Meals = meals
			}
		}()
	}

	wg.Wait()

	return data, nil
}

// fetchTasks fetches tasks from cache or API
func (h *Handler) fetchTasks(ctx context.Context, forceRefresh bool) ([]models.Task, error) {
	cacheKey := "todoist_tasks"

	// Check cache validity
	if !forceRefresh {
		valid, err := h.store.IsCacheValid(cacheKey)
		if err == nil && valid {
			return h.store.GetTasks()
		}
	}

	// Fetch from API
	tasks, err := h.todoistClient.GetTasks(ctx)
	if err != nil {
		// Try to return cached data even if stale
		cachedTasks, cacheErr := h.store.GetTasks()
		if cacheErr == nil && len(cachedTasks) > 0 {
			return cachedTasks, nil
		}
		return nil, err
	}

	// Save to cache
	if err := h.store.SaveTasks(tasks); err != nil {
		log.Printf("Failed to save tasks to cache: %v", err)
	}

	// Update cache metadata
	if err := h.store.UpdateCacheMetadata(cacheKey, h.config.CacheTTLMinutes); err != nil {
		log.Printf("Failed to update cache metadata: %v", err)
	}

	return tasks, nil
}

// fetchNotes fetches notes from cache or filesystem
func (h *Handler) fetchNotes(ctx context.Context, forceRefresh bool) ([]models.Note, error) {
	cacheKey := "obsidian_notes"

	// Check cache validity
	if !forceRefresh {
		valid, err := h.store.IsCacheValid(cacheKey)
		if err == nil && valid {
			return h.store.GetNotes(20)
		}
	}

	// Fetch from filesystem
	notes, err := h.obsidianClient.GetNotes(ctx, 20)
	if err != nil {
		// Try to return cached data even if stale
		cachedNotes, cacheErr := h.store.GetNotes(20)
		if cacheErr == nil && len(cachedNotes) > 0 {
			return cachedNotes, nil
		}
		return nil, err
	}

	// Save to cache
	if err := h.store.SaveNotes(notes); err != nil {
		log.Printf("Failed to save notes to cache: %v", err)
	}

	// Update cache metadata
	if err := h.store.UpdateCacheMetadata(cacheKey, h.config.CacheTTLMinutes); err != nil {
		log.Printf("Failed to update cache metadata: %v", err)
	}

	return notes, nil
}

// fetchMeals fetches meals from cache or API
func (h *Handler) fetchMeals(ctx context.Context, forceRefresh bool) ([]models.Meal, error) {
	cacheKey := "plantoeat_meals"

	// Check cache validity
	if !forceRefresh {
		valid, err := h.store.IsCacheValid(cacheKey)
		if err == nil && valid {
			startDate := time.Now()
			endDate := startDate.AddDate(0, 0, 7)
			return h.store.GetMeals(startDate, endDate)
		}
	}

	// Fetch from API
	meals, err := h.planToEatClient.GetUpcomingMeals(ctx, 7)
	if err != nil {
		// Try to return cached data even if stale
		startDate := time.Now()
		endDate := startDate.AddDate(0, 0, 7)
		cachedMeals, cacheErr := h.store.GetMeals(startDate, endDate)
		if cacheErr == nil && len(cachedMeals) > 0 {
			return cachedMeals, nil
		}
		return nil, err
	}

	// Save to cache
	if err := h.store.SaveMeals(meals); err != nil {
		log.Printf("Failed to save meals to cache: %v", err)
	}

	// Update cache metadata
	if err := h.store.UpdateCacheMetadata(cacheKey, h.config.CacheTTLMinutes); err != nil {
		log.Printf("Failed to update cache metadata: %v", err)
	}

	return meals, nil
}

// fetchBoards fetches Trello boards from cache or API
func (h *Handler) fetchBoards(ctx context.Context, forceRefresh bool) ([]models.Board, error) {
	cacheKey := "trello_boards"

	// Check cache validity
	if !forceRefresh {
		valid, err := h.store.IsCacheValid(cacheKey)
		if err == nil && valid {
			return h.store.GetBoards()
		}
	}

	// Fetch from API
	boards, err := h.trelloClient.GetBoardsWithCards(ctx)
	if err != nil {
		// Try to return cached data even if stale
		cachedBoards, cacheErr := h.store.GetBoards()
		if cacheErr == nil && len(cachedBoards) > 0 {
			return cachedBoards, nil
		}
		return nil, err
	}

	// Save to cache
	if err := h.store.SaveBoards(boards); err != nil {
		log.Printf("Failed to save boards to cache: %v", err)
	}

	// Update cache metadata
	if err := h.store.UpdateCacheMetadata(cacheKey, h.config.CacheTTLMinutes); err != nil {
		log.Printf("Failed to update cache metadata: %v", err)
	}

	return boards, nil
}