package main

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
)

func handleSuggestions(w http.ResponseWriter, r *http.Request) {
	query := r.URL.Query().Get("q")
	if query == "" {
		w.Header().Set("Content-Type", "application/json")
		fmt.Fprintf(w, `["",[]]`)
		return
	}

	// Define the fallback sequence with Google lower in the hierarchy
	suggestionSources := []func(string) []string{
		fetchDuckDuckGoSuggestions,
		fetchEdgeSuggestions,
		fetchBraveSuggestions,
		fetchEcosiaSuggestions,
		fetchQwantSuggestions,
		fetchStartpageSuggestions,
		// fetchGoogleSuggestions, // I advise against it, but you can use it if you want to
	}

	var suggestions []string
	for _, fetchFunc := range suggestionSources {
		suggestions = fetchFunc(query)
		if len(suggestions) > 0 {
			printDebug("Suggestions found using %T", fetchFunc)
			break
		} else {
			printWarn("%T did not return any suggestions or failed.", fetchFunc)
		}
	}

	if len(suggestions) == 0 {
		printErr("All suggestion services failed. Returning empty response.")
	}

	// Return the final suggestions as JSON
	w.Header().Set("Content-Type", "application/json")
	fmt.Fprintf(w, `["",%s]`, toJSONStringArray(suggestions))
}

func fetchGoogleSuggestions(query string) []string {
	encodedQuery := url.QueryEscape(query)
	url := fmt.Sprintf("http://suggestqueries.google.com/complete/search?client=firefox&q=%s", encodedQuery)
	printDebug("Fetching suggestions from Google: %s", url)
	return fetchSuggestionsFromURL(url)
}

func fetchDuckDuckGoSuggestions(query string) []string {
	encodedQuery := url.QueryEscape(query)
	url := fmt.Sprintf("https://duckduckgo.com/ac/?q=%s&type=list", encodedQuery)
	printDebug("Fetching suggestions from DuckDuckGo: %s", url)
	return fetchSuggestionsFromURL(url)
}

func fetchEdgeSuggestions(query string) []string {
	encodedQuery := url.QueryEscape(query)
	url := fmt.Sprintf("https://api.bing.com/osjson.aspx?query=%s", encodedQuery)
	printDebug("Fetching suggestions from Edge (Bing): %s", url)
	return fetchSuggestionsFromURL(url)
}

func fetchBraveSuggestions(query string) []string {
	encodedQuery := url.QueryEscape(query)
	url := fmt.Sprintf("https://search.brave.com/api/suggest?q=%s", encodedQuery)
	printDebug("Fetching suggestions from Brave: %s", url)
	return fetchSuggestionsFromURL(url)
}

func fetchEcosiaSuggestions(query string) []string {
	encodedQuery := url.QueryEscape(query)
	url := fmt.Sprintf("https://ac.ecosia.org/?q=%s&type=list", encodedQuery)
	printDebug("Fetching suggestions from Ecosia: %s", url)
	return fetchSuggestionsFromURL(url)
}

func fetchQwantSuggestions(query string) []string {
	encodedQuery := url.QueryEscape(query)
	url := fmt.Sprintf("https://api.qwant.com/v3/suggest?q=%s", encodedQuery)
	printDebug("Fetching suggestions from Qwant: %s", url)
	return fetchSuggestionsFromURL(url)
}

func fetchStartpageSuggestions(query string) []string {
	encodedQuery := url.QueryEscape(query)
	url := fmt.Sprintf("https://startpage.com/suggestions?q=%s", encodedQuery)
	printDebug("Fetching suggestions from Startpage: %s", url)
	return fetchSuggestionsFromURL(url)
}

func fetchSuggestionsFromURL(url string) []string {
	resp, err := http.Get(url)
	if err != nil {
		printWarn("Error fetching suggestions from %s: %v", url, err)
		return []string{}
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		printWarn("Error reading response body from %s: %v", url, err)
		return []string{}
	}

	// Log the Content-Type for debugging
	contentType := resp.Header.Get("Content-Type")
	printDebug("Response Content-Type from %s: %s", url, contentType)

	// Check if the body is non-empty
	if len(body) == 0 {
		printWarn("Received empty response body from %s", url)
		return []string{}
	}

	// Attempt to parse the response as JSON regardless of Content-Type
	var parsedResponse []interface{}
	if err := json.Unmarshal(body, &parsedResponse); err != nil {
		printErr("Error parsing JSON from %s: %v", url, err)
		printDebug("Response body: %s", string(body))
		return []string{}
	}

	// Ensure the response structure is as expected
	if len(parsedResponse) < 2 {
		printWarn("Unexpected response format from %v: %v", url, string(body))
		return []string{}
	}

	suggestions := []string{}
	if items, ok := parsedResponse[1].([]interface{}); ok {
		for _, item := range items {
			if suggestion, ok := item.(string); ok {
				suggestions = append(suggestions, suggestion)
			}
		}
	} else {
		printErr("Unexpected suggestions format in response from: %v", url)
	}

	return suggestions
}

func toJSONStringArray(strings []string) string {
	result := ""
	for i, str := range strings {
		result += fmt.Sprintf(`"%s"`, str)
		if i < len(strings)-1 {
			result += ","
		}
	}
	return "[" + result + "]"
}