package handlers

import (
	"html/template"
	"mealprep/auth"
	"mealprep/database"
	"net/http"
	"strconv"
	"strings"
)

// IngredientsHandler handles the ingredients page
func IngredientsHandler(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r)

	// Check if there's a search query
	searchTags := r.URL.Query().Get("tags")
	var ingredients []interface{}
	var err error

	if searchTags != "" {
		tagNames := strings.Split(searchTags, ",")
		for i := range tagNames {
			tagNames[i] = strings.TrimSpace(tagNames[i])
		}
		ings, err := database.SearchIngredientsByTags(userID, tagNames)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		for _, ing := range ings {
			ingredients = append(ingredients, ing)
		}
	} else {
		ings, err := database.GetIngredientsWithTags(userID)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		for _, ing := range ings {
			ingredients = append(ingredients, ing)
		}
	}

	// Get all available tags for the filter UI (only tags that are in use)
	allTags, err := database.GetUsedTags(userID)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	tmpl := `
		<div id="ingredients-content">
			<h2>Ingredients</h2>

			<form hx-post="/ingredients" hx-target="#ingredients-list" hx-swap="beforeend" class="add-form">
				<input type="text" name="name" placeholder="Ingredient name" required />
				<input type="text" name="unit" placeholder="Unit (e.g., grams, cups)" required />
				<input type="text" name="tags" placeholder="Tags (comma-separated)" />
				<button type="submit">Add Ingredient</button>
			</form>

			<div class="search-section">
				<h3>Filter by Tags</h3>
				<div class="tag-filter">
					{{range .AllTags}}
					<button class="tag-filter-btn"
							onclick="toggleTagFilter('{{.Name}}')">
						{{.Name}}
					</button>
					{{end}}
				</div>
				<div id="active-filters" class="active-filters"></div>
				<button onclick="clearFilters()" class="clear-filters-btn">Clear Filters</button>
			</div>

			<div id="ingredients-list" class="items-list">
				{{range .Ingredients}}
				<div class="item" id="ingredient-{{.ID}}">
					<div class="item-content">
						<span class="item-name">{{.Name}}</span>
						<span class="item-unit">({{.Unit}})</span>
						<div class="item-tags">
							{{range .Tags}}
							<span class="tag">{{.Name}}</span>
							{{end}}
						</div>
					</div>
					<div class="item-actions">
						<button
							hx-get="/ingredients/{{.ID}}/tags"
							hx-target="#tag-modal-content"
							hx-swap="innerHTML"
							onclick="document.getElementById('tag-modal').style.display='block'"
							class="edit-tags-btn">
							Edit Tags
						</button>
						<button
							hx-delete="/ingredients/{{.ID}}"
							hx-target="#ingredient-{{.ID}}"
							hx-swap="outerHTML"
							hx-confirm="Are you sure you want to delete this ingredient?"
							class="delete-btn">
							Delete
						</button>
					</div>
				</div>
				{{end}}
			</div>
		</div>

		<!-- Tag Edit Modal -->
		<div id="tag-modal" class="modal">
			<div class="modal-content">
				<span class="close" onclick="document.getElementById('tag-modal').style.display='none'">&times;</span>
				<div id="tag-modal-content">
					<!-- Content loaded via HTMX -->
				</div>
			</div>
		</div>

		<script>
			let activeFilters = new Set();

			// Listen for tag changes and refresh ingredients
			document.body.addEventListener('refreshIngredients', function() {
				// Close the modal first
				document.getElementById('tag-modal').style.display='none';
				// Then refresh the page
				htmx.ajax('GET', '/ingredients', {target: '#ingredients-content', swap: 'innerHTML'});
			});

			function toggleTagFilter(tagName) {
				if (activeFilters.has(tagName)) {
					activeFilters.delete(tagName);
				} else {
					activeFilters.add(tagName);
				}
				updateFilters();
			}

			function clearFilters() {
				activeFilters.clear();
				updateFilters();
			}

			function updateFilters() {
				// Update active filters display
				const activeFiltersDiv = document.getElementById('active-filters');
				if (activeFilters.size > 0) {
					activeFiltersDiv.innerHTML = 'Active filters: ' + Array.from(activeFilters).join(', ');
				} else {
					activeFiltersDiv.innerHTML = '';
				}

				// Update filter button states
				document.querySelectorAll('.tag-filter-btn').forEach(btn => {
					if (activeFilters.has(btn.textContent.trim())) {
						btn.classList.add('active');
					} else {
						btn.classList.remove('active');
					}
				});

				// Reload ingredients with filters
				const url = activeFilters.size > 0
					? '/ingredients?tags=' + Array.from(activeFilters).join(',')
					: '/ingredients';

				htmx.ajax('GET', url, {target: '#ingredients-content', swap: 'innerHTML'});
			}
		</script>
	`

	data := struct {
		Ingredients []interface{}
		AllTags     []interface{}
	}{
		Ingredients: ingredients,
		AllTags:     []interface{}{},
	}

	for _, tag := range allTags {
		data.AllTags = append(data.AllTags, tag)
	}

	t := template.Must(template.New("ingredients").Parse(tmpl))
	t.Execute(w, data)
}

// AddIngredientHandler handles adding a new ingredient
func AddIngredientHandler(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r)

	if err := r.ParseForm(); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	name := strings.TrimSpace(r.FormValue("name"))
	unit := strings.TrimSpace(r.FormValue("unit"))
	tagsStr := strings.TrimSpace(r.FormValue("tags"))

	if name == "" || unit == "" {
		http.Error(w, "Name and unit are required", http.StatusBadRequest)
		return
	}

	id, err := database.AddIngredient(userID, name, unit)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Process tags if provided
	var tags []string
	if tagsStr != "" {
		tagNames := strings.Split(tagsStr, ",")
		for _, tagName := range tagNames {
			tagName = strings.TrimSpace(tagName)
			if tagName != "" {
				// Get or create tag
				tagID, err := database.GetOrCreateTag(userID, tagName)
				if err != nil {
					continue // Skip this tag on error
				}
				// Link tag to ingredient
				database.AddIngredientTag(userID, int(id), int(tagID))
				tags = append(tags, tagName)
			}
		}
	}

	tmpl := `
		<div class="item" id="ingredient-{{.ID}}">
			<div class="item-content">
				<span class="item-name">{{.Name}}</span>
				<span class="item-unit">({{.Unit}})</span>
				<div class="item-tags">
					{{range .Tags}}
					<span class="tag">{{.}}</span>
					{{end}}
				</div>
			</div>
			<div class="item-actions">
				<button
					hx-get="/ingredients/{{.ID}}/tags"
					hx-target="#tag-modal-content"
					hx-swap="innerHTML"
					onclick="document.getElementById('tag-modal').style.display='block'"
					class="edit-tags-btn">
					Edit Tags
				</button>
				<button
					hx-delete="/ingredients/{{.ID}}"
					hx-target="#ingredient-{{.ID}}"
					hx-swap="outerHTML"
					hx-confirm="Are you sure you want to delete this ingredient?"
					class="delete-btn">
					Delete
				</button>
			</div>
		</div>
	`

	data := struct {
		ID   int64
		Name string
		Unit string
		Tags []string
	}{id, name, unit, tags}

	t := template.Must(template.New("ingredient").Parse(tmpl))
	t.Execute(w, data)
}

// DeleteIngredientHandler handles deleting an ingredient
func DeleteIngredientHandler(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r)

	idStr := strings.TrimPrefix(r.URL.Path, "/ingredients/")
	id, err := strconv.Atoi(idStr)
	if err != nil {
		http.Error(w, "Invalid ID", http.StatusBadRequest)
		return
	}

	if err := database.DeleteIngredient(userID, id); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	w.WriteHeader(http.StatusOK)
}

// GetIngredientTagsHandler returns the tag editing UI for an ingredient
func GetIngredientTagsHandler(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r)

	// Extract ingredient ID from path /ingredients/{id}/tags
	pathParts := strings.Split(strings.TrimPrefix(r.URL.Path, "/ingredients/"), "/")
	if len(pathParts) < 1 {
		http.Error(w, "Invalid path", http.StatusBadRequest)
		return
	}

	ingredientID, err := strconv.Atoi(pathParts[0])
	if err != nil {
		http.Error(w, "Invalid ingredient ID", http.StatusBadRequest)
		return
	}

	// Get current tags for ingredient
	currentTags, err := database.GetIngredientTags(userID, ingredientID)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Get all available tags
	allTags, err := database.GetAllTags(userID)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Build a set of current tag IDs for easy lookup
	currentTagIDs := make(map[int]bool)
	for _, tag := range currentTags {
		currentTagIDs[tag.ID] = true
	}

	tmpl := `
		<h3>Edit Tags</h3>
		<div class="tag-edit-section">
			<h4>Current Tags</h4>
			<div id="current-tags-{{.IngredientID}}">
				{{range .CurrentTags}}
				<span class="tag">
					{{.Name}}
					<button
						hx-delete="/ingredients/{{$.IngredientID}}/tags/{{.ID}}"
						hx-target="#current-tags-{{$.IngredientID}}"
						hx-swap="innerHTML"
						class="tag-remove">
						×
					</button>
				</span>
				{{end}}
			</div>

			<h4>Add Tags</h4>
			<form hx-post="/ingredients/{{.IngredientID}}/tags"
				  hx-target="#current-tags-{{.IngredientID}}"
				  hx-swap="innerHTML"
				  class="add-tag-form">
				<input type="text" name="tag_name" placeholder="New tag name" list="existing-tags" required />
				<datalist id="existing-tags">
					{{range .AllTags}}
					{{if not (index $.CurrentTagIDs .ID)}}
					<option value="{{.Name}}">
					{{end}}
					{{end}}
				</datalist>
				<button type="submit">Add Tag</button>
			</form>
		</div>
	`

	data := struct {
		IngredientID  int
		CurrentTags   []interface{}
		AllTags       []interface{}
		CurrentTagIDs map[int]bool
	}{
		IngredientID:  ingredientID,
		CurrentTags:   []interface{}{},
		AllTags:       []interface{}{},
		CurrentTagIDs: currentTagIDs,
	}

	for _, tag := range currentTags {
		data.CurrentTags = append(data.CurrentTags, tag)
	}
	for _, tag := range allTags {
		data.AllTags = append(data.AllTags, tag)
	}

	t := template.Must(template.New("ingredient-tags").Parse(tmpl))
	t.Execute(w, data)
}

// AddIngredientTagHandler adds a tag to an ingredient
func AddIngredientTagHandler(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r)

	// Extract ingredient ID from path
	pathParts := strings.Split(strings.TrimPrefix(r.URL.Path, "/ingredients/"), "/")
	if len(pathParts) < 1 {
		http.Error(w, "Invalid path", http.StatusBadRequest)
		return
	}

	ingredientID, err := strconv.Atoi(pathParts[0])
	if err != nil {
		http.Error(w, "Invalid ingredient ID", http.StatusBadRequest)
		return
	}

	if err := r.ParseForm(); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}

	tagName := strings.TrimSpace(r.FormValue("tag_name"))
	if tagName == "" {
		http.Error(w, "Tag name is required", http.StatusBadRequest)
		return
	}

	// Get or create the tag
	tagID, err := database.GetOrCreateTag(userID, tagName)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Add tag to ingredient
	if err := database.AddIngredientTag(userID, ingredientID, int(tagID)); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Return updated tag list with trigger to refresh page
	w.Header().Set("HX-Trigger", "refreshIngredients")
	renderCurrentTags(w, userID, ingredientID)
}

// RemoveIngredientTagHandler removes a tag from an ingredient
func RemoveIngredientTagHandler(w http.ResponseWriter, r *http.Request) {
	userID := auth.GetUserID(r)

	// Extract ingredient ID and tag ID from path /ingredients/{ingredient_id}/tags/{tag_id}
	pathParts := strings.Split(strings.TrimPrefix(r.URL.Path, "/ingredients/"), "/")
	if len(pathParts) < 3 {
		http.Error(w, "Invalid path", http.StatusBadRequest)
		return
	}

	ingredientID, err := strconv.Atoi(pathParts[0])
	if err != nil {
		http.Error(w, "Invalid ingredient ID", http.StatusBadRequest)
		return
	}

	tagID, err := strconv.Atoi(pathParts[2])
	if err != nil {
		http.Error(w, "Invalid tag ID", http.StatusBadRequest)
		return
	}

	// Remove tag from ingredient
	if err := database.RemoveIngredientTag(userID, ingredientID, tagID); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Return updated tag list with trigger to refresh page
	w.Header().Set("HX-Trigger", "refreshIngredients")
	renderCurrentTags(w, userID, ingredientID)
}

// Helper function to render current tags
func renderCurrentTags(w http.ResponseWriter, userID, ingredientID int) {
	currentTags, err := database.GetIngredientTags(userID, ingredientID)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	tmpl := `
		{{range .Tags}}
		<span class="tag">
			{{.Name}}
			<button
				hx-delete="/ingredients/{{$.IngredientID}}/tags/{{.ID}}"
				hx-target="#current-tags-{{$.IngredientID}}"
				hx-swap="innerHTML"
				class="tag-remove">
				×
			</button>
		</span>
		{{end}}
	`

	type TagWithID struct {
		ID   int
		Name string
	}

	data := struct {
		Tags         []TagWithID
		IngredientID int
	}{
		Tags:         []TagWithID{},
		IngredientID: ingredientID,
	}

	for _, tag := range currentTags {
		data.Tags = append(data.Tags, TagWithID{ID: tag.ID, Name: tag.Name})
	}

	t := template.Must(template.New("current-tags").Parse(tmpl))
	t.Execute(w, data)
}