package main

import (
	"flag"
	"fmt"
	"html/template"
	"log"
	"net/http"
	"sort"
	"sync"
	"time"
)

type TextSearchResult struct {
	URL         string
	Header      string
	Description string
	Source      string
}

var debugMode bool

func init() {
	flag.BoolVar(&debugMode, "debug", false, "enable debug mode")
	flag.Parse()
}

func HandleTextSearch(w http.ResponseWriter, query, safe, lang string) {
	startTime := time.Now()
	var combinedResults []TextSearchResult
	var resultMap = make(map[string]TextSearchResult)
	var wg sync.WaitGroup
	var mu sync.Mutex

	resultsChan := make(chan []TextSearchResult)

	searchFuncs := []struct {
		Func   func(string, string, string) ([]TextSearchResult, error)
		Source string
	}{
		{PerformGoogleTextSearch, "Google"},
		{PerformDuckDuckGoTextSearch, "DuckDuckGo"},
		{PerformQwantTextSearch, "Qwant"},
	}

	wg.Add(len(searchFuncs))

	for _, searchFunc := range searchFuncs {
		go func(searchFunc func(string, string, string) ([]TextSearchResult, error), source string) {
			defer wg.Done()
			results, err := searchFunc(query, safe, lang)
			if err == nil {
				for i := range results {
					results[i].Source = source
				}
				resultsChan <- results
			} else {
				log.Printf("Error performing search from %s: %v", source, err)
			}
		}(searchFunc.Func, searchFunc.Source)
	}

	go func() {
		wg.Wait()
		close(resultsChan)
	}()

	for results := range resultsChan {
		mu.Lock()
		for _, result := range results {
			existingResult, exists := resultMap[result.URL]
			if !exists || shouldReplace(existingResult.Source, result.Source) {
				resultMap[result.URL] = result
			}
			if debugMode {
				log.Printf("Result from %s: %+v\n", result.Source, result)
			}
		}
		mu.Unlock()
	}

	// Convert the map back to a slice
	for _, result := range resultMap {
		combinedResults = append(combinedResults, result)
	}

	// Custom sorting: Google first, DuckDuckGo second, Qwant third
	sort.SliceStable(combinedResults, func(i, j int) bool {
		return sourceOrder(combinedResults[i].Source) < sourceOrder(combinedResults[j].Source)
	})

	displayResults(w, combinedResults, query, lang, time.Since(startTime).Seconds())
}

func shouldReplace(existingSource, newSource string) bool {
	return sourceOrder(newSource) < sourceOrder(existingSource)
}

func sourceOrder(source string) int {
	switch source {
	case "Qwant":
		return 1
	case "DuckDuckGo":
		return 2
	case "Google":
		return 3
	default:
		return 4
	}
}

func displayResults(w http.ResponseWriter, results []TextSearchResult, query, lang string, elapsed float64) {
	tmpl, err := template.ParseFiles("templates/text.html")
	if err != nil {
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
		return
	}

	data := struct {
		Results         []TextSearchResult
		Query           string
		Fetched         string
		LanguageOptions []LanguageOption
		CurrentLang     string
	}{
		Results:         results,
		Query:           query,
		Fetched:         fmt.Sprintf("%.2f seconds", elapsed),
		LanguageOptions: languageOptions,
		CurrentLang:     lang,
	}

	err = tmpl.Execute(w, data)
	if err != nil {
		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
	}
}