package realdebrid

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

func UnrestrictCheck(accessToken, link string) (*UnrestrictResponse, error) {
	data := url.Values{}
	data.Set("link", link)

	req, err := http.NewRequest("POST", "https://api.real-debrid.com/rest/1.0/unrestrict/check", bytes.NewBufferString(data.Encode()))
	if err != nil {
		return nil, err
	}

	req.Header.Set("Authorization", "Bearer "+accessToken)
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")

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

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("HTTP error: %s", resp.Status)
	}

	var response UnrestrictResponse
	err = json.Unmarshal(body, &response)
	if err != nil {
		return nil, err
	}

	return &response, nil
}

func UnrestrictLink(accessToken, link string) (*UnrestrictResponse, error) {
	data := url.Values{}
	data.Set("link", link)

	req, err := http.NewRequest("POST", "https://api.real-debrid.com/rest/1.0/unrestrict/link", bytes.NewBufferString(data.Encode()))
	if err != nil {
		return nil, err
	}

	req.Header.Set("Authorization", "Bearer "+accessToken)
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")

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

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("HTTP error: %s", resp.Status)
	}

	var response UnrestrictResponse
	err = json.Unmarshal(body, &response)
	if err != nil {
		return nil, err
	}

	if !canFetchFirstByte(response.Download) {
		return nil, fmt.Errorf("can't fetch first byte")
	}
	return &response, nil
}

func canFetchFirstByte(url string) bool {
	// Create a new HTTP request
	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return false
	}

	// Set the Range header to request only the first byte
	req.Header.Set("Range", "bytes=0-0")

	// Execute the request
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return false
	}
	defer resp.Body.Close()

	// If server supports partial content
	if resp.StatusCode == http.StatusPartialContent {
		buffer := make([]byte, 1)
		_, err := resp.Body.Read(buffer)
		return err == nil
	}
	if resp.StatusCode != http.StatusOK {
		return false
	}
	// If server doesn't support partial content, try reading the first byte and immediately close
	buffer := make([]byte, 1)
	_, err = resp.Body.Read(buffer)
	resp.Body.Close() // Close immediately after reading
	return err == nil
}

// GetTorrents returns all torrents, paginated
// if customLimit is 0, the default limit of 2500 is used
func GetTorrents(accessToken string, customLimit int) ([]Torrent, int, error) {
	baseURL := "https://api.real-debrid.com/rest/1.0/torrents"
	var allTorrents []Torrent
	page := 1
	limit := customLimit
	if limit == 0 {
		limit = 2500
	}
	totalCount := 0

	for {
		params := url.Values{}
		params.Set("page", fmt.Sprintf("%d", page))
		params.Set("limit", fmt.Sprintf("%d", limit))

		reqURL := baseURL + "?" + params.Encode()

		req, err := http.NewRequest("GET", reqURL, nil)
		if err != nil {
			return nil, 0, err
		}

		req.Header.Set("Authorization", "Bearer "+accessToken)

		client := &http.Client{}
		resp, err := client.Do(req)
		if err != nil {
			return nil, 0, err
		}
		defer resp.Body.Close()

		if resp.StatusCode != http.StatusOK {
			return nil, 0, fmt.Errorf("HTTP error: %s", resp.Status)
		}

		var torrents []Torrent
		decoder := json.NewDecoder(resp.Body)
		err = decoder.Decode(&torrents)
		if err != nil {
			return nil, 0, err
		}

		allTorrents = append(allTorrents, torrents...)

		totalCountHeader := resp.Header.Get("x-total-count")
		totalCount, err = strconv.Atoi(totalCountHeader)
		if err != nil {
			break
		}

		if len(allTorrents) >= totalCount || (customLimit != 0 && customLimit <= len(allTorrents) && customLimit <= totalCount) {
			break
		}

		page++
	}

	return allTorrents, totalCount, nil
}

func GetTorrentInfo(accessToken, id string) (*Torrent, error) {
	url := "https://api.real-debrid.com/rest/1.0/torrents/info/" + id

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

	req.Header.Set("Authorization", "Bearer "+accessToken)

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

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("HTTP error: %s", resp.Status)
	}

	var response Torrent
	err = json.Unmarshal(body, &response)
	if err != nil {
		return nil, err
	}

	return &response, nil
}