// Copyright 2019 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT

package repository

import (
	"context"
	"fmt"
	"path/filepath"
	"sort"
	"strings"

	issues_model "code.gitea.io/gitea/models/issues"
	"code.gitea.io/gitea/modules/label"
	"code.gitea.io/gitea/modules/options"
	"code.gitea.io/gitea/modules/setting"
	"code.gitea.io/gitea/modules/util"
)

type OptionFile struct {
	DisplayName string
	Description string
}

var (
	// Gitignores contains the gitiginore files
	Gitignores []string

	// Licenses contains the license files
	Licenses []string

	// Readmes contains the readme files
	Readmes []string

	// LabelTemplateFiles contains the label template files, each item has its DisplayName and Description
	LabelTemplateFiles   []OptionFile
	labelTemplateFileMap = map[string]string{} // DisplayName => FileName mapping
)

type optionFileList struct {
	all    []string // all files provided by bindata & custom-path. Sorted.
	custom []string // custom files provided by custom-path. Non-sorted, internal use only.
}

// mergeCustomLabelFiles merges the custom label files. Always use the file's main name (DisplayName) as the key to de-duplicate.
func mergeCustomLabelFiles(fl optionFileList) []string {
	exts := map[string]int{"": 0, ".yml": 1, ".yaml": 2} // "yaml" file has the highest priority to be used.

	m := map[string]string{}
	merge := func(list []string) {
		sort.Slice(list, func(i, j int) bool { return exts[filepath.Ext(list[i])] < exts[filepath.Ext(list[j])] })
		for _, f := range list {
			m[strings.TrimSuffix(f, filepath.Ext(f))] = f
		}
	}
	merge(fl.all)
	merge(fl.custom)

	files := make([]string, 0, len(m))
	for _, f := range m {
		files = append(files, f)
	}
	sort.Strings(files)
	return files
}

// LoadRepoConfig loads the repository config
func LoadRepoConfig() error {
	types := []string{"gitignore", "license", "readme", "label"} // option file directories
	typeFiles := make([]optionFileList, len(types))
	for i, t := range types {
		var err error
		if typeFiles[i].all, err = options.AssetFS().ListFiles(t, true); err != nil {
			return fmt.Errorf("failed to list %s files: %w", t, err)
		}
		sort.Strings(typeFiles[i].all)
		customPath := filepath.Join(setting.CustomPath, "options", t)
		if isDir, err := util.IsDir(customPath); err != nil {
			return fmt.Errorf("failed to check custom %s dir: %w", t, err)
		} else if isDir {
			if typeFiles[i].custom, err = util.ListDirRecursively(customPath, &util.ListDirOptions{SkipCommonHiddenNames: true}); err != nil {
				return fmt.Errorf("failed to list custom %s files: %w", t, err)
			}
		}
	}

	Gitignores = typeFiles[0].all
	Licenses = typeFiles[1].all
	Readmes = typeFiles[2].all

	// Load label templates
	LabelTemplateFiles = nil
	labelTemplateFileMap = map[string]string{}
	for _, file := range mergeCustomLabelFiles(typeFiles[3]) {
		description, err := label.LoadTemplateDescription(file)
		if err != nil {
			return fmt.Errorf("failed to load labels: %w", err)
		}
		displayName := strings.TrimSuffix(file, filepath.Ext(file))
		labelTemplateFileMap[displayName] = file
		LabelTemplateFiles = append(LabelTemplateFiles, OptionFile{DisplayName: displayName, Description: description})
	}

	// Filter out invalid names and promote preferred licenses.
	sortedLicenses := make([]string, 0, len(Licenses))
	for _, name := range setting.Repository.PreferredLicenses {
		if util.SliceContainsString(Licenses, name, true) {
			sortedLicenses = append(sortedLicenses, name)
		}
	}
	for _, name := range Licenses {
		if !util.SliceContainsString(setting.Repository.PreferredLicenses, name, true) {
			sortedLicenses = append(sortedLicenses, name)
		}
	}
	Licenses = sortedLicenses
	return nil
}

// InitializeLabels adds a label set to a repository using a template
func InitializeLabels(ctx context.Context, id int64, labelTemplate string, isOrg bool) error {
	list, err := LoadTemplateLabelsByDisplayName(labelTemplate)
	if err != nil {
		return err
	}

	labels := make([]*issues_model.Label, len(list))
	for i := range list {
		labels[i] = &issues_model.Label{
			Name:           list[i].Name,
			Exclusive:      list[i].Exclusive,
			ExclusiveOrder: list[i].ExclusiveOrder,
			Description:    list[i].Description,
			Color:          list[i].Color,
		}
		if isOrg {
			labels[i].OrgID = id
		} else {
			labels[i].RepoID = id
		}
	}
	for _, label := range labels {
		if err = issues_model.NewLabel(ctx, label); err != nil {
			return err
		}
	}
	return nil
}

// LoadTemplateLabelsByDisplayName loads a label template by its display name
func LoadTemplateLabelsByDisplayName(displayName string) ([]*label.Label, error) {
	if fileName, ok := labelTemplateFileMap[displayName]; ok {
		return label.LoadTemplateFile(fileName)
	}
	return nil, label.ErrTemplateLoad{TemplateFile: displayName, OriginalError: fmt.Errorf("label template %q not found", displayName)}
}
