// 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 plugin

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

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

// Args provides plugin execution arguments.
type Args struct {
	Pipeline

	// Level defines the plugin log level.
	Level string `envconfig:"PLUGIN_LOG_LEVEL"`

	Folder             string `envconfig:"PLUGIN_FOLDER"`
	SshKey             string `envconfig:"PLUGIN_SSH_KEY"`
	GitRemote          string `envconfig:"PLUGIN_GIT_REMOTE"`
	GitBranch          string `envconfig:"PLUGIN_GIT_BRANCH"`
	GitRemoteFromDrone string `envconfig:"DRONE_GIT_SSH_URL"`
}

const BRANCH_NAME = "pages"

// Exec executes the plugin.
func Exec(ctx context.Context, args Args) error {

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

	if err := repo.WriteKey(strings.ReplaceAll(args.SshKey, "\\n", "\n") + "\n"); err != nil {
		return err
	}

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

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

	if err := initRepo(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.Folder == "" {
		return errors.New("PLUGIN_FOLDER is required!")
	}

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

	if args.SshKey == "" {
		return errors.New("PLUGIN_SSH_KEY is required!")
	}

	if args.GitRemote == "" && args.GitRemoteFromDrone == "" {
		return errors.New("PLUGIN_GIT_REMOTE is required!")
	}

	if args.GitRemote == "" && args.GitRemoteFromDrone != "" {
		args.GitRemote = args.GitRemoteFromDrone
	}

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

	return nil
}

func writeConfig(args Args) error {
	if err := repo.GlobalName("[BOT] pages deployer").Run(); err != nil {
		return err
	}

	if err := repo.GlobalUser("noreply@pages.bot").Run(); err != nil {
		return err
	}

	return nil
}

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

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

	cmd := exec.Command("mv", folder, "/tmp/pages")
	if err := execute(cmd); err != nil {
		return err
	}

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

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

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

	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)); err != nil {
		return err
	}

	return nil
}

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