// Copyright 2020 the Drone Authors. All rights reserved.
// Use of this source code is governed by the Blue Oak Model License
// that can be found in the LICENSE file.

package main

import (
	"errors"
	"fmt"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"strings"

	"github.com/kelseyhightower/envconfig"

	"github.com/appleboy/drone-git-push/repo"
)

// Args provides plugin execution arguments.
type Args struct {
	Folder       string `required:"true" envconfig:"INPUT_FOLDER"`
	RemoteFolder string `envconfig:"INPUT_REMOTE_FOLDER" default:"/"`
	SshKey       string `envconfig:"INPUT_SSH_KEY"`
	GitRemote    string `envconfig:"INPUT_GIT_REMOTE"`
	GitBranch    string `envconfig:"INPUT_GIT_BRANCH"`
	GitName      string `envconfig:"INPUT_GIT_NAME" default:"[BOT] pages deployer"`
	GitEmail     string `envconfig:"INPUT_GIT_EMAIL" default:"noreply@pages.bot"`
	Token        string `envconfig:"INPUT_TOKEN"`
	Username     string `envconfig:"INPUT_USERNAME"`
	Force        bool   `envconfig:"INPUT_FORCE" default:"false"`

	GithubToken      string `envconfig:"GITHUB_TOKEN"`
	GithubTokenActor string `envconfig:"GITHUB_ACTOR"`
	GithubRepository string `envconfig:"GITHUB_REPOSITORY"`
	GithubServerUrl  string `envconfig:"GITHUB_SERVER_URL"`
}

const BRANCH_NAME = "pages"

func main() {
	var args Args
	if err := envconfig.Process("", &args); err != nil {
		log.Fatalln(err)
	}

	if err := Exec(args); err != nil {
		log.Fatalln(err)
	}

}

// Exec executes the plugin.
func Exec(args Args) error {
	if err := checkArgs(&args); err != nil {
		return err
	}

	if args.SshKey != "" {
		if err := repo.WriteKey(strings.ReplaceAll(args.SshKey, "\\n", "\n") + "\n"); err != nil {
			return err
		}
	} else {
		var err error
		args.GitRemote, err = repo.WriteToken(args.GitRemote, args.Username, args.Token)
		if err != nil {
			return err
		}
	}

	if err := cleanTempDir(); err != nil {
		return err
	}

	if args.Force {
		if err := initRepo(args); err != nil {
			return err
		}
	} else {
		if err := cloneRepo(args); err != nil {
			return err
		}
	}

	if err := copyFiles(args); err != nil {
		return err
	}

	if err := writeConfig(args); err != nil {
		return err
	}

	if err := doCommit(args); err != nil {
		return err
	}

	if err := push(args); err != nil {
		return err
	}

	// write code here
	return nil
}

func checkArgs(args *Args) error {
	if args.Token == "" && args.GithubToken != "" {
		args.Token = args.GithubToken
	}

	if args.Username == "" && args.GithubTokenActor != "" {
		args.Username = args.GithubTokenActor
	}

	if (args.Token == "" || args.Username == "") && args.SshKey == "" {
		return errors.New("(INPUT_TOKEN and INPUT_USERNAME) or INPUT_SSH_KEY is required!")
	}

	if folderInfo, err := os.Stat(args.Folder); os.IsNotExist(err) || !folderInfo.IsDir() {
		return errors.New("INPUT_FOLDER is not a folder!")
	}

	if args.GitRemote == "" && (args.GithubServerUrl == "" || args.GithubRepository == "") {
		return errors.New("INPUT_GIT_REMOTE is required!")
	}

	if args.GitRemote == "" {
		args.GitRemote = fmt.Sprintf("%s/%s.git", args.GithubServerUrl, args.GithubRepository)
	}

	if args.GitBranch == "" {
		args.GitBranch = BRANCH_NAME
	}

	folder, err := filepath.Abs(args.Folder)
	if err != nil {
		return err
	}

	args.Folder = folder

	_, err = os.Stat(args.Folder)
	if err != nil {
		return err
	}

	return nil
}

func writeConfig(args Args) error {
	if err := execute(exec.Command("git", "config", "user.name", args.GitName)); err != nil {
		return err
	}

	if err := execute(exec.Command("git", "config", "user.email", args.GitEmail)); err != nil {
		return err
	}

	return nil
}

func cleanTempDir() error {
	if err := os.RemoveAll("/tmp/pages"); err != nil {
		return err
	}

	if err := os.MkdirAll("/tmp", 777); err != nil {
		return err
	}

	return nil
}

func copyFiles(args Args) error {
	if args.Folder[len(args.Folder)-1:] != "/" {
		args.Folder += "/"
	}

	if args.RemoteFolder[:1] != "/" {
		args.RemoteFolder = "/" + args.RemoteFolder
	}

	cmd := exec.Command("rsync", "-av", args.Folder, "/tmp/pages"+args.RemoteFolder, "--exclude", ".git", "--ignore-times", "--delete")
	if err := execute(cmd); err != nil {
		return err
	}

	if err := os.Chown("/tmp/pages", os.Getuid(), os.Getgid()); err != nil {
		return err
	}

	return nil
}

func initRepo(args Args) error {
	cmd := exec.Command(
		"git",
		"init", "-b", args.GitBranch, "/tmp/pages")

	if err := execute(cmd); err != nil {
		return err
	}

	return os.Chdir("/tmp/pages")
}

func cloneRepo(args Args) error {
	cmd := exec.Command(
		"git",
		"clone", args.GitRemote, "/tmp/pages")

	if err := execute(cmd); err != nil {
		return err
	}

	// check if branch exists and create if not
	cmd = exec.Command(
		"git",
		"ls-remote", "--heads", args.GitRemote, args.GitBranch)

	out, err := cmd.Output()
	if err != nil {
		return err
	}

	fmt.Println("remote branch: ", string(out))

	if err := os.Chdir("/tmp/pages"); err != nil {
		return err
	}

	if len(out) == 0 {
		cmd = exec.Command(
			"git",
			"checkout", "-b", args.GitBranch)
	} else {
		cmd = exec.Command(
			"git",
			"checkout", args.GitBranch)
	}

	if err := execute(cmd); err != nil {
		return err
	}

	return nil
}

func doCommit(args Args) error {
	if err := execute(repo.Add()); err != nil {
		return err
	}

	if err := execute(repo.ForceCommit("Update pages  🚀", true, args.GitName, args.GitEmail)); err != nil {
		return err
	}

	return nil
}

func push(args Args) error {
	return execute(repo.RemotePushNamedBranch(args.GitRemote, args.GitBranch, args.GitBranch, args.Force, false))
}

func execute(cmd *exec.Cmd) error {
	fmt.Println("+", strings.Join(cmd.Args, " "))

	cmd.Env = os.Environ()
	cmd.Stderr = os.Stderr
	cmd.Stdin = os.Stdin

	return cmd.Run()
}