// Copyright 2021 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.

package repository

import (
	"errors"
	"fmt"

	"code.gitea.io/gitea/models"
	"code.gitea.io/gitea/modules/git"
	"code.gitea.io/gitea/modules/log"
	"code.gitea.io/gitea/modules/notification"
	repo_module "code.gitea.io/gitea/modules/repository"
	pull_service "code.gitea.io/gitea/services/pull"
)

// CreateNewBranch creates a new repository branch
func CreateNewBranch(doer *models.User, repo *models.Repository, oldBranchName, branchName string) (err error) {
	// Check if branch name can be used
	if err := checkBranchName(repo, branchName); err != nil {
		return err
	}

	if !git.IsBranchExist(repo.RepoPath(), oldBranchName) {
		return models.ErrBranchDoesNotExist{
			BranchName: oldBranchName,
		}
	}

	if err := git.Push(repo.RepoPath(), git.PushOptions{
		Remote: repo.RepoPath(),
		Branch: fmt.Sprintf("%s:%s%s", oldBranchName, git.BranchPrefix, branchName),
		Env:    models.PushingEnvironment(doer, repo),
	}); err != nil {
		if git.IsErrPushOutOfDate(err) || git.IsErrPushRejected(err) {
			return err
		}
		return fmt.Errorf("Push: %v", err)
	}

	return nil
}

// GetBranches returns branches from the repository, skipping skip initial branches and
// returning at most limit branches, or all branches if limit is 0.
func GetBranches(repo *models.Repository, skip, limit int) ([]*git.Branch, int, error) {
	return git.GetBranchesByPath(repo.RepoPath(), skip, limit)
}

// checkBranchName validates branch name with existing repository branches
func checkBranchName(repo *models.Repository, name string) error {
	gitRepo, err := git.OpenRepository(repo.RepoPath())
	if err != nil {
		return err
	}
	defer gitRepo.Close()

	branches, _, err := GetBranches(repo, 0, 0)
	if err != nil {
		return err
	}

	for _, branch := range branches {
		if branch.Name == name {
			return models.ErrBranchAlreadyExists{
				BranchName: branch.Name,
			}
		} else if (len(branch.Name) < len(name) && branch.Name+"/" == name[0:len(branch.Name)+1]) ||
			(len(branch.Name) > len(name) && name+"/" == branch.Name[0:len(name)+1]) {
			return models.ErrBranchNameConflict{
				BranchName: branch.Name,
			}
		}
	}

	if _, err := gitRepo.GetTag(name); err == nil {
		return models.ErrTagAlreadyExists{
			TagName: name,
		}
	}

	return nil
}

// CreateNewBranchFromCommit creates a new repository branch
func CreateNewBranchFromCommit(doer *models.User, repo *models.Repository, commit, branchName string) (err error) {
	// Check if branch name can be used
	if err := checkBranchName(repo, branchName); err != nil {
		return err
	}

	if err := git.Push(repo.RepoPath(), git.PushOptions{
		Remote: repo.RepoPath(),
		Branch: fmt.Sprintf("%s:%s%s", commit, git.BranchPrefix, branchName),
		Env:    models.PushingEnvironment(doer, repo),
	}); err != nil {
		if git.IsErrPushOutOfDate(err) || git.IsErrPushRejected(err) {
			return err
		}
		return fmt.Errorf("Push: %v", err)
	}

	return nil
}

// RenameBranch rename a branch
func RenameBranch(repo *models.Repository, doer *models.User, gitRepo *git.Repository, from, to string) (string, error) {
	if from == to {
		return "target_exist", nil
	}

	if gitRepo.IsBranchExist(to) {
		return "target_exist", nil
	}

	if !gitRepo.IsBranchExist(from) {
		return "from_not_exist", nil
	}

	if err := repo.RenameBranch(from, to, func(isDefault bool) error {
		err2 := gitRepo.RenameBranch(from, to)
		if err2 != nil {
			return err2
		}

		if isDefault {
			err2 = gitRepo.SetDefaultBranch(to)
			if err2 != nil {
				return err2
			}
		}

		return nil
	}); err != nil {
		return "", err
	}

	notification.NotifyDeleteRef(doer, repo, "branch", "refs/heads/"+from)
	notification.NotifyCreateRef(doer, repo, "branch", "refs/heads/"+to)

	return "", nil
}

// enmuerates all branch related errors
var (
	ErrBranchIsDefault   = errors.New("branch is default")
	ErrBranchIsProtected = errors.New("branch is protected")
)

// DeleteBranch delete branch
func DeleteBranch(doer *models.User, repo *models.Repository, gitRepo *git.Repository, branchName string) error {
	if branchName == repo.DefaultBranch {
		return ErrBranchIsDefault
	}

	isProtected, err := repo.IsProtectedBranch(branchName)
	if err != nil {
		return err
	}

	if isProtected {
		return ErrBranchIsProtected
	}

	commit, err := gitRepo.GetBranchCommit(branchName)
	if err != nil {
		return err
	}

	if err := gitRepo.DeleteBranch(branchName, git.DeleteBranchOptions{
		Force: true,
	}); err != nil {
		return err
	}

	if err := pull_service.CloseBranchPulls(doer, repo.ID, branchName); err != nil {
		return err
	}

	// Don't return error below this
	if err := PushUpdate(
		&repo_module.PushUpdateOptions{
			RefFullName:  git.BranchPrefix + branchName,
			OldCommitID:  commit.ID.String(),
			NewCommitID:  git.EmptySHA,
			PusherID:     doer.ID,
			PusherName:   doer.Name,
			RepoUserName: repo.OwnerName,
			RepoName:     repo.Name,
		}); err != nil {
		log.Error("Update: %v", err)
	}

	if err := repo.AddDeletedBranch(branchName, commit.ID.String(), doer.ID); err != nil {
		log.Warn("AddDeletedBranch: %v", err)
	}

	return nil
}