package services

import (
	"bytes"
	"context"
	"fmt"
	"io"
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"strings"

	"gitea.com/gitea/pr-deployer/pkgs/settings"

	"github.com/cloudflare/cloudflare-go"
	"github.com/docker/docker/api/types"
	"github.com/docker/docker/client"
	"github.com/pkg/errors"
	log "github.com/sirupsen/logrus"
	"golang.org/x/oauth2"
)

func UpdateAndStartPullRequest(ctx context.Context, client Client, number int, sha string) error {
	log.Trace("CheckWebhook")
	if err := client.CheckWebhook(ctx); err != nil {
		return err
	}

	// 0 download the git
	log.Trace("updateGitRepo")

	newSHA, err := updateGitRepo(number, sha)
	if err != nil {
		return err
	}

	log.Trace("UpdateCommitStatus pending", newSHA)
	// 1 send commit status
	if err := client.UpdateCommitStatus(ctx, number, newSHA, statusPending, "", ""); err != nil {
		return err
	}

	if err := updateAndStartPullRequest(ctx, client, number, newSHA); err != nil {
		log.Errorf("UpdateCommitStatus %s failure: %v", newSHA, err)
		if err := client.UpdateCommitStatus(ctx, number, newSHA, statusFailure, err.Error(), ""); err != nil {
			return err
		}
	}
	return nil
}

func updateAndStartPullRequest(ctx context.Context, client Client, number int, newSHA string) error {
	log.Trace("checkAndUpdateSubDomain")
	// 2 change domain
	if err := checkAndUpdateSubDomain(number); err != nil {
		return err
	}

	log.Trace("buildImage")
	// 3 build
	if err := buildImage(ctx, number); err != nil {
		return err
	}

	log.Trace("runImage")
	// 4 change reverse server
	if err := runImage(ctx, number); err != nil {
		return err
	}

	log.Trace("UpdateCommitStatus success", newSHA)
	// 5 send commit status
	if err := client.UpdateCommitStatus(ctx, number, newSHA, statusSuccess, "", fmt.Sprintf("https://try-pr-%d.gitea.io", number)); err != nil {
		return err
	}

	return nil
}

func runImage(ctx context.Context, number int) error {
	cli, err := client.NewClientWithOpts(client.FromEnv)
	if err != nil {
		return err
	}

	// TODO: stop the old container

	// start the new container
	_, err = cli.ContainerExecCreate(ctx, fmt.Sprintf("%s/%s:%s", settings.RepoOwner, settings.RepoName, getImageTag(number)), types.ExecConfig{
		WorkingDir: getPRDir(number),
	})
	return err
}

const (
	statusPending = "pending"
	statusSuccess = "success"
	statusError   = "error"
	statusFailure = "failure"
)

func getPRDir(number int) string {
	return filepath.Join(settings.CodeCacheDir, strconv.Itoa(number))
}

func WithDir(cmd *exec.Cmd, dir string) *exec.Cmd {
	cmd.Dir = dir
	return cmd
}

func updateGitRepo(number int, sha string) (string, error) {
	p := getPRDir(number)
	log.Trace("clone code into", p)

	var local = fmt.Sprintf("pull/%d/head:pr/%d", number, number)
	st, err := os.Stat(p)
	if err != nil {
		if os.IsNotExist(err) {
			if err := exec.Command("git", "clone", settings.RepoURL, p).Run(); err != nil {
				return "", fmt.Errorf("git clone: %v", err)
			}

			cmd := exec.Command("git", "fetch", "origin", local)
			if err := WithDir(cmd, p).Run(); err != nil {
				return "", errors.Wrap(err, "fetch")
			}
		}
		return "", err
	}
	if !st.IsDir() {
		return "", fmt.Errorf("%s is a file but not a dir", p)
	}

	cmd := exec.Command("git", "pull", "origin", local)
	if err := WithDir(cmd, p).Run(); err != nil {
		return "", errors.Wrap(err, fmt.Sprintf("checkout %s", sha))
	}

	var branchName = fmt.Sprintf("pr/%d", number)
	var newSHA = sha

	if sha != "" {
		cmd := exec.Command("git", "checkout", sha)
		if err := WithDir(cmd, p).Run(); err != nil {
			return "", errors.Wrap(err, fmt.Sprintf("checkout %s", sha))
		}
		newSHA = sha
	} else {
		cmd := exec.Command("git", "rev-parse", "--abbrev-ref", "HEAD")
		cmd.Dir = p
		var buf bytes.Buffer
		cmd.Stdout = &buf
		if err := cmd.Run(); err != nil {
			return "", fmt.Errorf("rev-parse --abbrev-ref: %v", err)
		}

		if buf.String() != branchName {
			cmd := exec.Command("git", "checkout", branchName)
			if err := WithDir(cmd, p).Run(); err != nil {
				return "", fmt.Errorf("git checkout %s: %v", branchName, err)
			}
		}

		cmd = exec.Command("git", "rev-parse", "HEAD")
		cmd.Dir = p
		var buf2 bytes.Buffer
		cmd.Stdout = &buf2
		if err := cmd.Run(); err != nil {
			return "", fmt.Errorf("git rev-parse Head: %v", err)
		}
		newSHA = strings.TrimSpace(buf2.String())
	}

	return newSHA, nil
}

func getImageTag(number int) string {
	return fmt.Sprintf("pr-%d", number)
}

// buildImage build the docker image via Dockerfile
func buildImage(ctx context.Context, number int) error {
	cli, err := client.NewClientWithOpts(client.FromEnv)
	if err != nil {
		return err
	}

	var buildContext io.Reader
	if _, err = cli.ImageBuild(ctx, buildContext, types.ImageBuildOptions{
		Tags: []string{getImageTag(number)},
	}); err != nil {
		return err
	}

	return nil
}

func checkAndUpdateSubDomain(number int) error {
	api, err := cloudflare.NewWithAPIToken(settings.CloudflareToken)
	if err != nil {
		return err
	}

	zoneID, err := api.ZoneIDByName("gitea.io")
	if err != nil {
		return err
	}

	var found bool
	var name = fmt.Sprintf("try-pr-%d.gitea.io", number)
	foo := cloudflare.DNSRecord{
		Type: "name",
		Name: name,
	}
	recs, err := api.DNSRecords(context.Background(), zoneID, foo)
	if err != nil {
		return err
	}

	for _, r := range recs {
		if name == r.Name {
			found = true
			break
		}
	}
	if found {
		// check ip address
		return nil
	}

	asciiInput := cloudflare.DNSRecord{
		Type:    "A",
		Name:    name,
		Content: settings.DomainIP,
		TTL:     120,
		//Priority: &priority,
		//Proxied:  &proxied,
	}

	_, err = api.CreateDNSRecord(context.Background(), zoneID, asciiInput)
	if err != nil {
		return err
	}
	return nil
}

func StopPullRequest(number int) error {
	return nil
}

func NewClient(token *oauth2.Token) (Client, error) {
	if settings.ServiceType == "github" {
		return NewGithubClient(token), nil
	}

	return nil, fmt.Errorf("unsupported service type: %s", settings.ServiceType)
}