package agent

import (
	"context"
	"crypto/tls"
	"errors"
	"fmt"
	"io"
	"net/http"
	"strconv"
	"time"

	portainer "github.com/portainer/portainer/api"
	"github.com/portainer/portainer/api/url"
	"github.com/portainer/portainer/pkg/libhttp/ssrf"

	"github.com/rs/zerolog/log"
)

// GetAgentVersionAndPlatform returns the agent version and platform
//
// it sends a ping to the agent and parses the version and platform from the headers
func GetAgentVersionAndPlatform(endpointUrl string, tlsConfig *tls.Config) (portainer.AgentPlatform, string, error) { //nolint:forbidigo
	if err := ssrf.CheckURL(context.Background(), endpointUrl); err != nil {
		return 0, "", err
	}

	httpCli := &http.Client{Timeout: 3 * time.Second}

	if tlsConfig != nil {
		httpCli.Transport = ssrf.NewTransport(tlsConfig)
	}

	parsedURL, err := url.ParseURL(endpointUrl + "/ping")
	if err != nil {
		return 0, "", err
	}

	parsedURL.Scheme = "https"

	req, err := http.NewRequest(http.MethodGet, parsedURL.String(), nil)
	if err != nil {
		return 0, "", err
	}

	resp, err := httpCli.Do(req)
	if err != nil {
		return 0, "", err
	}

	_, _ = io.Copy(io.Discard, resp.Body)
	if err := resp.Body.Close(); err != nil {
		log.Warn().Err(err).Msg("failed to close response body")
	}

	if resp.StatusCode != http.StatusNoContent {
		return 0, "", fmt.Errorf("Failed request with status %d", resp.StatusCode)
	}

	version := resp.Header.Get(portainer.PortainerAgentHeader)
	if version == "" {
		return 0, "", errors.New("Version Header is missing")
	}

	agentPlatformHeader := resp.Header.Get(portainer.HTTPResponseAgentPlatform)
	if agentPlatformHeader == "" {
		return 0, "", errors.New("Agent Platform Header is missing")
	}

	agentPlatformNumber, err := strconv.Atoi(agentPlatformHeader)
	if err != nil {
		return 0, "", err
	}

	if agentPlatformNumber == 0 {
		return 0, "", errors.New("Agent platform is invalid")
	}

	return portainer.AgentPlatform(agentPlatformNumber), version, nil
}