package main

import (
	"context"
	"fmt"
	"net/url"
	"strings"
	"time"

	"github.com/PuerkitoBio/goquery"
	"github.com/chromedp/chromedp"
)

func PerformGoogleTextSearch(query, safe, lang string, page int) ([]TextSearchResult, error) {
	opts := append(chromedp.DefaultExecAllocatorOptions[:],
		chromedp.DisableGPU,
		chromedp.NoDefaultBrowserCheck,
		chromedp.NoFirstRun,
		chromedp.Flag("disable-javascript", true),
	)
	ctx, cancel := chromedp.NewExecAllocator(context.Background(), opts...)
	defer cancel()

	ctx, cancel = chromedp.NewContext(ctx)
	defer cancel()

	var results []TextSearchResult

	searchURL := buildSearchURL(query, safe, lang, page, 10)
	var pageSource string
	err := chromedp.Run(ctx,
		chromedp.Navigate(searchURL),
		chromedp.Sleep(2*time.Second),
		chromedp.OuterHTML("html", &pageSource),
	)
	if err != nil {
		return nil, fmt.Errorf("failed to retrieve page source: %v", err)
	}

	newResults, err := parseResults(pageSource)
	if err != nil {
		return nil, fmt.Errorf("error parsing results: %v", err)
	}
	results = append(results, newResults...)

	return results, nil
}

func buildSearchURL(query, safe, lang string, page, resultsPerPage int) string {
	safeParam := "&safe=off"
	if safe == "active" {
		safeParam = "&safe=active"
	}

	langParam := ""
	if lang != "" {
		langParam = "&lr=" + lang
	}

	startParam := fmt.Sprintf("&start=%d", (page-1)*resultsPerPage)

	return fmt.Sprintf("https://www.google.com/search?q=%s%s%s%s", url.QueryEscape(query), safeParam, langParam, startParam)
}

func parseResults(pageSource string) ([]TextSearchResult, error) {
	var results []TextSearchResult

	doc, err := goquery.NewDocumentFromReader(strings.NewReader(pageSource))
	if err != nil {
		return nil, fmt.Errorf("loading HTML document: %v", err)
	}

	doc.Find(".yuRUbf").Each(func(i int, s *goquery.Selection) {
		link := s.Find("a")
		href, exists := link.Attr("href")
		if !exists {
			return
		}

		header := link.Find("h3").Text()
		header = strings.TrimSpace(strings.TrimSuffix(header, "›"))

		description := ""
		descSelection := doc.Find(".VwiC3b").Eq(i)
		if descSelection.Length() > 0 {
			description = descSelection.Text()
		}

		result := TextSearchResult{
			URL:         href,
			Header:      header,
			Description: description,
		}
		results = append(results, result)
	})

	return results, nil
}