// Package torguard contains code to obtain the server information
// for the Torguard provider.
package torguard

import (
	"context"
	"errors"
	"fmt"
	"strings"

	"github.com/qdm12/gluetun/internal/models"
	"github.com/qdm12/gluetun/internal/updater/openvpn"
	"github.com/qdm12/gluetun/internal/updater/unzip"
)

var ErrNotEnoughServers = errors.New("not enough servers found")

func GetServers(ctx context.Context, unzipper unzip.Unzipper, minServers int) (
	servers []models.TorguardServer, warnings []string, err error) {
	const url = "https://torguard.net/downloads/OpenVPN-TCP-Linux.zip"
	contents, err := unzipper.FetchAndExtract(ctx, url)
	if err != nil {
		return nil, nil, err
	} else if len(contents) < minServers {
		return nil, nil, fmt.Errorf("%w: %d and expected at least %d",
			ErrNotEnoughServers, len(contents), minServers)
	}

	servers = make([]models.TorguardServer, 0, len(contents))
	for fileName, content := range contents {
		if !strings.HasSuffix(fileName, ".ovpn") {
			continue // not an OpenVPN file
		}

		country, city := parseFilename(fileName)

		host, warning, err := openvpn.ExtractHost(content)
		if warning != "" {
			warnings = append(warnings, warning)
		}
		if err != nil {
			// treat error as warning and go to next file
			warning := err.Error() + " in " + fileName
			warnings = append(warnings, warning)
			continue
		}

		ip, warning, err := openvpn.ExtractIP(content)
		if warning != "" {
			warnings = append(warnings, warning)
		}
		if err != nil {
			// treat error as warning and go to next file
			warning := err.Error() + " in " + fileName
			warnings = append(warnings, warning)
			continue
		}

		server := models.TorguardServer{
			Country:  country,
			City:     city,
			Hostname: host,
			IP:       ip,
		}
		servers = append(servers, server)
	}

	if len(servers) < minServers {
		return nil, warnings, fmt.Errorf("%w: %d and expected at least %d",
			ErrNotEnoughServers, len(servers), minServers)
	}

	sortServers(servers)

	return servers, warnings, nil
}