package utils

import (
	"compress/gzip"
	"context"
	"fmt"
	"io"
	"net/http"
	"os"
)

var httpClient http.Client

func DownloadE6Data(ctx context.Context, filename string, targetPath string) error {
	req, err := buildE6Request(fmt.Sprintf("/db_export/%s", filename))

	if err != nil {
		return err
	}

	req = req.WithContext(ctx)
	resp, err := httpClient.Do(req)

	if err != nil {
		return err
	}
	defer resp.Body.Close()

	uncompressedStream, err := gzip.NewReader(resp.Body)

	if err != nil {
		return err
	}
	defer uncompressedStream.Close()

	out, err := os.Create(targetPath)

	if err != nil {
		return err
	}

	defer out.Close()
	_, err = io.Copy(out, uncompressedStream)

	return err
}

func buildE6Request(url string) (*http.Request, error) {
	request, err := http.NewRequest("GET", fmt.Sprintf("%s%s", "https://e621.net", url), nil)
	if err != nil {
		return nil, err
	}

	request.Header.Add("User-Agent", "Anthrove downloader (by alphyron)")

	return request, nil
}