// Copyright 2015 The Gogs Authors. All rights reserved.
// Copyright 2021 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT

package git

import (
	"errors"
	"os"
	"path/filepath"
	"strings"

	"code.gitea.io/gitea/modules/util"
)

// hookNames is a list of Git server hooks' name that are supported.
var hookNames = []string{
	"pre-receive",
	"update",
	"post-receive",
}

// ErrNotValidHook error when a git hook is not valid
var ErrNotValidHook = errors.New("not a valid Git hook")

// IsValidHookName returns true if given name is a valid Git hook.
func IsValidHookName(name string) bool {
	for _, hn := range hookNames {
		if hn == name {
			return true
		}
	}
	return false
}

// Hook represents a Git hook.
type Hook struct {
	name     string
	IsActive bool   // Indicates whether repository has this hook.
	Content  string // Content of hook if it's active.
	Sample   string // Sample content from Git.
	path     string // Hook file path.
}

// GetHook returns a Git hook by given name and repository.
func GetHook(repoPath, name string) (*Hook, error) {
	if !IsValidHookName(name) {
		return nil, ErrNotValidHook
	}
	h := &Hook{
		name: name,
		path: filepath.Join(repoPath, "hooks", name+".d", name),
	}
	isFile, err := util.IsFile(h.path)
	if err != nil {
		return nil, err
	}
	if isFile {
		data, err := os.ReadFile(h.path)
		if err != nil {
			return nil, err
		}
		h.IsActive = true
		h.Content = string(data)
		return h, nil
	}

	samplePath := filepath.Join(repoPath, "hooks", name+".sample")
	isFile, err = util.IsFile(samplePath)
	if err != nil {
		return nil, err
	}
	if isFile {
		data, err := os.ReadFile(samplePath)
		if err != nil {
			return nil, err
		}
		h.Sample = string(data)
	}
	return h, nil
}

// Name return the name of the hook
func (h *Hook) Name() string {
	return h.name
}

// Update updates hook settings.
func (h *Hook) Update() error {
	if len(strings.TrimSpace(h.Content)) == 0 {
		exist, err := util.IsExist(h.path)
		if err != nil {
			return err
		}
		if exist {
			err := util.Remove(h.path)
			if err != nil {
				return err
			}
		}
		h.IsActive = false
		return nil
	}
	d := filepath.Dir(h.path)
	if err := os.MkdirAll(d, os.ModePerm); err != nil {
		return err
	}

	err := os.WriteFile(h.path, []byte(strings.ReplaceAll(h.Content, "\r", "")), os.ModePerm)
	if err != nil {
		return err
	}
	h.IsActive = true
	return nil
}

// ListHooks returns a list of Git hooks of given repository.
func ListHooks(repoPath string) (_ []*Hook, err error) {
	exist, err := util.IsDir(filepath.Join(repoPath, "hooks"))
	if err != nil {
		return nil, err
	} else if !exist {
		return nil, errors.New("hooks path does not exist")
	}

	hooks := make([]*Hook, len(hookNames))
	for i, name := range hookNames {
		hooks[i], err = GetHook(repoPath, name)
		if err != nil {
			return nil, err
		}
	}
	return hooks, nil
}