package main

import (
	"crypto/md5"
	"encoding/hex"
	"fmt"
	"net/http"
	"time"
)

var imageSearchEngines []SearchEngine

func init() {
	imageSearchEngines = []SearchEngine{
		{Name: "Qwant", Func: wrapImageSearchFunc(PerformQwantImageSearch)},
		{Name: "Bing", Func: wrapImageSearchFunc(PerformBingImageSearch)},
		{Name: "DeviantArt", Func: wrapImageSearchFunc(PerformDeviantArtImageSearch)},
		//{Name: "Imgur", Func: wrapImageSearchFunc(PerformImgurImageSearch), Weight: 4}, // Image proxy not working
	}
}

func handleImageSearch(w http.ResponseWriter, settings UserSettings, query string, page int) {
	startTime := time.Now()

	cacheKey := CacheKey{Query: query, Page: page, Safe: settings.SafeSearch == "active", Lang: settings.SearchLanguage, Type: "image"}
	combinedResults := getImageResultsFromCacheOrFetch(cacheKey, query, settings.SafeSearch, settings.SearchLanguage, page)

	elapsedTime := time.Since(startTime)

	// Prepare the data to pass to the template
	data := map[string]interface{}{
		"Results":          combinedResults,
		"Query":            query,
		"Fetched":          fmt.Sprintf("%.2f %s", elapsedTime.Seconds(), Translate("seconds")), // Time for fetching
		"Page":             page,
		"HasPrevPage":      page > 1,
		"HasNextPage":      len(combinedResults) >= 50,
		"NoResults":        len(combinedResults) == 0,
		"LanguageOptions":  languageOptions,
		"CurrentLang":      settings.SearchLanguage,
		"Theme":            settings.Theme,
		"Safe":             settings.SafeSearch,
		"IsThemeDark":      settings.IsThemeDark,
		"HardCacheEnabled": config.HardCacheDuration == 0,
	}

	// Render the template without measuring the time
	renderTemplate(w, "images.html", data)
}

func getImageResultsFromCacheOrFetch(cacheKey CacheKey, query, safe, lang string, page int) []ImageSearchResult {
	cacheChan := make(chan []SearchResult)
	var combinedResults []ImageSearchResult

	go func() {
		results, exists := resultsCache.Get(cacheKey)
		if exists {
			printInfo("Cache hit")
			cacheChan <- results
		} else {
			printInfo("Cache miss")
			cacheChan <- nil
		}
	}()

	select {
	case results := <-cacheChan:
		if results == nil {
			combinedResults = fetchImageResults(query, safe, lang, page)
			if len(combinedResults) > 0 {
				combinedResults = filterValidImages(combinedResults)
				resultsCache.Set(cacheKey, convertToSearchResults(combinedResults))
			}
		} else {
			_, _, imageResults := convertToSpecificResults(results)
			combinedResults = filterValidImages(imageResults)
		}
	case <-time.After(2 * time.Second):
		printInfo("Cache check timeout")
		combinedResults = fetchImageResults(query, safe, lang, page)
		if len(combinedResults) > 0 {
			combinedResults = filterValidImages(combinedResults)
			resultsCache.Set(cacheKey, convertToSearchResults(combinedResults))
		}
	}

	return combinedResults
}

func fetchImageResults(query, safe, lang string, page int) []ImageSearchResult {
	var results []ImageSearchResult
	engineCount := len(imageSearchEngines)
	safeBool := safe == "active"

	// Determine the engine to use based on the page number
	engineIndex := (page - 1) % engineCount
	engine := imageSearchEngines[engineIndex]

	// Calculate the specific page number for the selected engine
	enginePage := (page-1)/engineCount + 1

	// Debug print to verify the selected engine and page
	printInfo("Fetching image results for overall page %d using engine: %s (engine page %d)", page, engine.Name, enginePage)

	// Fetch results from the selected engine
	searchResults, _, err := engine.Func(query, safe, lang, enginePage)
	if err != nil {
		printWarn("Error performing image search with %s: %v", engine.Name, err)
	} else {
		for _, result := range searchResults {
			imageResult := result.(ImageSearchResult)
			if config.HardCacheEnabled {
				// Generate hash and set up caching
				hasher := md5.New()
				hasher.Write([]byte(imageResult.Full))
				hash := hex.EncodeToString(hasher.Sum(nil))
				filename := hash + ".webp"
				imageResult.ID = hash
				imageResult.ProxyFull = "/image_cache/" + filename

				// Start caching and validation in the background
				go func(imgResult ImageSearchResult, originalURL, filename string) {
					_, success, err := cacheImage(originalURL, filename, imgResult.ID)
					if err != nil {
						printWarn("Failed to cache image %s: %v", originalURL, err)
					}
					if !success {
						removeImageResultFromCache(query, page, safeBool, lang, imgResult.ID)
					}
				}(imageResult, imageResult.Full, filename)
			} else {
				// Use proxied URLs when hard cache is disabled
				imageResult.ProxyThumb = "/imgproxy?url=" + imageResult.Thumb
				imageResult.ProxyFull = "/imgproxy?url=" + imageResult.Full
			}
			results = append(results, imageResult)
		}
	}

	// Fallback mechanism if no results are fetched from the selected engine
	if len(results) == 0 {
		printWarn("No image results found with engine %s, trying other engines.", engine.Name)
		for i := 1; i < engineCount; i++ {
			nextEngine := imageSearchEngines[(engineIndex+i)%engineCount]
			enginePage = (page-1)/engineCount + 1 // Recalculate page for next engine
			printInfo("Trying next image search engine: %s (engine page %d)", nextEngine.Name, enginePage)

			searchResults, _, err := nextEngine.Func(query, safe, lang, enginePage)
			if err != nil {
				printWarn("Error performing image search with %s: %v", nextEngine.Name, err)
				continue
			}
			for _, result := range searchResults {
				imageResult := result.(ImageSearchResult)
				if config.HardCacheEnabled {
					// Generate hash and set up caching
					hasher := md5.New()
					hasher.Write([]byte(imageResult.Full))
					hash := hex.EncodeToString(hasher.Sum(nil))
					filename := hash + ".webp"
					imageResult.ID = hash
					imageResult.ProxyFull = "/image_cache/" + filename

					// Start caching and validation in the background
					go func(imgResult ImageSearchResult, originalURL, filename string) {
						_, success, err := cacheImage(originalURL, filename, imgResult.ID)
						if err != nil {
							printWarn("Failed to cache image %s: %v", originalURL, err)
						}
						if !success {
							removeImageResultFromCache(query, page, safeBool, lang, imgResult.ID)
						}
					}(imageResult, imageResult.Full, filename)
				} else {
					// Use proxied URLs when hard cache is disabled
					imageResult.ProxyThumb = "/imgproxy?url=" + imageResult.Thumb
					imageResult.ProxyFull = "/imgproxy?url=" + imageResult.Full
				}
				results = append(results, imageResult)
			}

			if len(results) > 0 {
				break
			}
		}
	}

	// Final debug print to show the count of results fetched
	printInfo("Fetched %d image results for overall page %d", len(results), page)

	return results
}

func wrapImageSearchFunc(f func(string, string, string, int) ([]ImageSearchResult, time.Duration, error)) func(string, string, string, int) ([]SearchResult, time.Duration, error) {
	return func(query, safe, lang string, page int) ([]SearchResult, time.Duration, error) {
		imageResults, duration, err := f(query, safe, lang, page)
		if err != nil {
			return nil, duration, err
		}
		searchResults := make([]SearchResult, len(imageResults))
		for i, result := range imageResults {
			searchResults[i] = result
		}
		return searchResults, duration, nil
	}
}

// func isValidImageURL(imageURL string) bool {
// 	client := &http.Client{
// 		Timeout: 10 * time.Second,
// 		Transport: &http.Transport{
// 			TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
// 		},
// 	}

// 	req, err := http.NewRequest("GET", imageURL, nil)
// 	if err != nil {
// 		return false
// 	}

// 	// Set headers to mimic a real browser
// 	req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) "+
// 		"AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.141 Safari/537.36")
// 	req.Header.Set("Accept", "image/webp,image/*,*/*;q=0.8")
// 	req.Header.Set("Accept-Language", "en-US,en;q=0.9")
// 	req.Header.Set("Referer", imageURL) // Some servers require a referer

// 	resp, err := client.Do(req)
// 	if err != nil {
// 		return false
// 	}
// 	defer resp.Body.Close()

// 	if resp.StatusCode < 200 || resp.StatusCode >= 400 {
// 		return false
// 	}

// 	// Limit the amount of data read to 10KB
// 	limitedReader := io.LimitReader(resp.Body, 10240) // 10KB

// 	// Attempt to decode image configuration
// 	_, _, err = image.DecodeConfig(limitedReader)
// 	if err != nil {
// 		return false
// 	}

// 	return true
// }

// // This function can be used alternatively to isValidImageURL(), Its slower but reliable
// func isImageAccessible(imageURL string) bool {
// 	client := &http.Client{
// 		Timeout: 5 * time.Second,
// 		CheckRedirect: func(req *http.Request, via []*http.Request) error {
// 			if len(via) >= 10 {
// 				return http.ErrUseLastResponse
// 			}
// 			return nil
// 		},
// 	}

// 	resp, err := client.Get(imageURL)
// 	if err != nil {
// 		return false
// 	}
// 	defer resp.Body.Close()

// 	if resp.StatusCode < 200 || resp.StatusCode >= 400 {
// 		return false
// 	}

// 	// Read the entire image data
// 	data, err := io.ReadAll(resp.Body)
// 	if err != nil {
// 		return false
// 	}

// 	// Try to decode the image
// 	_, _, err = image.Decode(bytes.NewReader(data))
// 	if err != nil {
// 		return false
// 	}

// 	return true
// }