package api

import (
	"context"
	"fmt"
	"io"
	"log"
	"net/http"
	"strings"
	"time"

	"github.com/PuerkitoBio/goquery"

	"task-dashboard/internal/models"
)

const (
	planToEatBaseURL = "https://www.plantoeat.com/api/v2"
	planToEatWebURL  = "https://app.plantoeat.com"
)

// PlanToEatClient handles interactions with the PlanToEat API
type PlanToEatClient struct {
	BaseClient
	apiKey        string
	sessionCookie string // For web scraping endpoints
}

// NewPlanToEatClient creates a new PlanToEat API client
func NewPlanToEatClient(apiKey string) *PlanToEatClient {
	return &PlanToEatClient{
		BaseClient: NewBaseClient(planToEatBaseURL),
		apiKey:     apiKey,
	}
}

// SetSessionCookie sets the session cookie for web scraping endpoints
func (c *PlanToEatClient) SetSessionCookie(cookie string) {
	c.sessionCookie = cookie
}

// GetUpcomingMeals fetches meals by scraping the planner web interface
// Requires a valid session cookie set via SetSessionCookie
func (c *PlanToEatClient) GetUpcomingMeals(ctx context.Context, days int) ([]models.Meal, error) {
	if c.sessionCookie == "" {
		return nil, fmt.Errorf("session cookie required for meals - use SetSessionCookie")
	}

	if days <= 0 {
		days = 7
	}

	req, err := http.NewRequestWithContext(ctx, "GET", planToEatWebURL+"/planner", nil)
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Cookie", c.sessionCookie)
	req.Header.Set("Accept", "text/html")
	req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36")

	resp, err := c.HTTPClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("request failed: %w", err)
	}
	defer func() { _ = resp.Body.Close() }()

	log.Printf("DEBUG [PlanToEat/Meals]: Response status %d", resp.StatusCode)

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("unexpected status %d (session may be expired)", resp.StatusCode)
	}

	return parsePlannerHTML(resp.Body, days)
}

// parsePlannerHTML extracts meals from the planner page HTML
func parsePlannerHTML(body io.Reader, days int) ([]models.Meal, error) {
	doc, err := goquery.NewDocumentFromReader(body)
	if err != nil {
		return nil, fmt.Errorf("failed to parse HTML: %w", err)
	}

	// Check for login page
	title := doc.Find("title").First().Text()
	titleLower := strings.ToLower(title)
	log.Printf("DEBUG [PlanToEat/Meals]: Page title: %q", title)
	if strings.Contains(titleLower, "login") || strings.Contains(titleLower, "log in") || strings.Contains(titleLower, "sign in") {
		return nil, fmt.Errorf("session expired - got login page (title: %s)", title)
	}

	var meals []models.Meal
	now := time.Now()
	today := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
	endDate := today.AddDate(0, 0, days)

	// PlanToEat structure:
	// - Day cells have data-date="YYYY-MM-DD"
	// - Within each day, sections: <div class="time" data-section="breakfast|lunch|dinner|xtra">
	// - Meal items inside sections: <div data-id="..." data-recipe-id="...">
	// - Recipe name: <a class="title recipe">Name</a>
	// - Non-recipe: <span class="title item">Name</span>

	// Find all day cells with data-date
	doc.Find("[data-date]").Each(func(_ int, dayEl *goquery.Selection) {
		dateStr, exists := dayEl.Attr("data-date")
		if !exists {
			return
		}

		mealDate, err := time.Parse("2006-01-02", dateStr)
		if err != nil {
			return
		}

		// Skip dates outside our range
		if mealDate.Before(today) || mealDate.After(endDate) {
			return
		}

		// Find meal sections within this day
		dayEl.Find("div.time[data-section]").Each(func(_ int, sectionEl *goquery.Selection) {
			section, _ := sectionEl.Attr("data-section")
			mealType := normalizeMealType(section)

			// Find meal items within this section
			sectionEl.Find("[data-id]").Each(func(_ int, itemEl *goquery.Selection) {
				meal := models.Meal{
					Date:     mealDate,
					MealType: mealType,
				}

				// Get ID
				if id, exists := itemEl.Attr("data-id"); exists {
					meal.ID = id
				}

				// Try to get recipe name from a.title.recipe or span.title.item
				if recipeLink := itemEl.Find("a.title.recipe, a.title").First(); recipeLink.Length() > 0 {
					meal.RecipeName = strings.TrimSpace(recipeLink.Text())
					if href, exists := recipeLink.Attr("href"); exists {
						// Convert /recipes/{id}/{event_id} to /recipes/{id}/cook/{event_id}
						if strings.HasPrefix(href, "/recipes/") {
							parts := strings.Split(href, "/")
							if len(parts) == 4 { // ["", "recipes", "id", "event_id"]
								href = fmt.Sprintf("/recipes/%s/cook/%s", parts[2], parts[3])
							}
						}
						if !strings.HasPrefix(href, "http") {
							meal.RecipeURL = planToEatWebURL + href
						} else {
							meal.RecipeURL = href
						}
					}
				} else if titleSpan := itemEl.Find("span.title.item, span.title").First(); titleSpan.Length() > 0 {
					meal.RecipeName = strings.TrimSpace(titleSpan.Text())
				}

				if meal.RecipeName != "" {
					meals = append(meals, meal)
				}
			})
		})
	})

	log.Printf("DEBUG [PlanToEat/Meals]: Found %d meals", len(meals))

	return meals, nil
}

// normalizeMealType ensures meal type matches DB constraint (breakfast, lunch, dinner, snack)
func normalizeMealType(mealType string) string {
	lower := strings.ToLower(strings.TrimSpace(mealType))
	switch lower {
	case "breakfast":
		return "breakfast"
	case "lunch":
		return "lunch"
	case "dinner":
		return "dinner"
	case "snack", "xtra", "snacks":
		return "snack"
	default:
		return "dinner"
	}
}

// GetRecipes fetches recipes (for Phase 2)
func (c *PlanToEatClient) GetRecipes(ctx context.Context) error {
	return fmt.Errorf("not implemented yet")
}

// AddMealToPlanner adds a meal to the planner (for Phase 2)
func (c *PlanToEatClient) AddMealToPlanner(ctx context.Context, recipeID string, date time.Time, mealType string) error {
	return fmt.Errorf("not implemented yet")
}

// GetShoppingList fetches the shopping list by scraping the web interface
// Requires a valid session cookie set via SetSessionCookie
func (c *PlanToEatClient) GetShoppingList(ctx context.Context) ([]models.ShoppingItem, error) {
	if c.sessionCookie == "" {
		return nil, fmt.Errorf("session cookie required for shopping list - use SetSessionCookie")
	}

	req, err := http.NewRequestWithContext(ctx, "GET", planToEatWebURL+"/shopping_lists", nil)
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Cookie", c.sessionCookie)
	req.Header.Set("Accept", "text/html")
	req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36")

	log.Printf("DEBUG [PlanToEat/Shopping]: Fetching %s", planToEatWebURL+"/shopping_lists")

	resp, err := c.HTTPClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("request failed: %w", err)
	}
	defer func() { _ = resp.Body.Close() }()

	log.Printf("DEBUG [PlanToEat/Shopping]: Response status %d", resp.StatusCode)

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("unexpected status %d (session may be expired)", resp.StatusCode)
	}

	return parseShoppingListHTML(resp.Body)
}

// parseShoppingListHTML extracts shopping items from the HTML response
func parseShoppingListHTML(body io.Reader) ([]models.ShoppingItem, error) {
	doc, err := goquery.NewDocumentFromReader(body)
	if err != nil {
		return nil, fmt.Errorf("failed to parse HTML: %w", err)
	}

	var items []models.ShoppingItem
	currentStore := ""
	currentCategory := ""

	// Debug: log page title and structure hints
	title := doc.Find("title").First().Text()
	log.Printf("DEBUG [PlanToEat/Shopping]: Page title: %q", title)

	// Check if we got a login page
	titleLower := strings.ToLower(title)
	if strings.Contains(titleLower, "login") || strings.Contains(titleLower, "log in") || strings.Contains(titleLower, "sign in") {
		return nil, fmt.Errorf("session expired - got login page (title: %s)", title)
	}

	// Debug: count elements to understand structure
	storeCount := doc.Find("div.store").Length()
	log.Printf("DEBUG [PlanToEat/Shopping]: Found %d div.store elements", storeCount)

	// Iterate through stores
	doc.Find("div.store").Each(func(_ int, store *goquery.Selection) {
		currentStore = strings.TrimSpace(store.Find("h4.store_name").First().Text())
		// Clean up store name (remove count and icons)
		if idx := strings.Index(currentStore, "("); idx > 0 {
			currentStore = strings.TrimSpace(currentStore[:idx])
		}

		log.Printf("DEBUG [PlanToEat/Shopping]: Processing store: %q", currentStore)

		// Iterate through categories within store
		store.Find("div.category-box").Each(func(_ int, catBox *goquery.Selection) {
			currentCategory = strings.TrimSpace(catBox.Find("p.category-title span").First().Text())

			// Iterate through items in category
			catBox.Find("li.sli").Each(func(_ int, li *goquery.Selection) {
				item := models.ShoppingItem{
					Store:    currentStore,
					Category: currentCategory,
				}

				// Extract ID from class (e.g., "sli i493745889")
				if class, exists := li.Attr("class"); exists {
					for _, c := range strings.Fields(class) {
						if strings.HasPrefix(c, "i") && len(c) > 1 {
							item.ID = c[1:] // Remove 'i' prefix
							break
						}
					}
				}

				// Extract name
				item.Name = strings.TrimSpace(li.Find("strong").First().Text())

				// Extract quantity
				item.Quantity = strings.TrimSpace(li.Find("span.quan").First().Text())
				// Clean up HTML entities in quantity
				item.Quantity = cleanQuantity(item.Quantity)

				// Check if item is checked (has specific class or attribute)
				if li.HasClass("checked") || li.HasClass("crossed") {
					item.Checked = true
				}

				if item.Name != "" {
					items = append(items, item)
				}
			})
		})
	})

	log.Printf("DEBUG [PlanToEat/Shopping]: Parsed %d items total", len(items))

	return items, nil
}

// cleanQuantity removes HTML entities and extra whitespace from quantity strings
func cleanQuantity(q string) string {
	q = strings.ReplaceAll(q, "\u00a0", " ") // non-breaking space
	q = strings.ReplaceAll(q, "  ", " ")
	return strings.TrimSpace(q)
}