package rpm

import "io/fs"
import "path/filepath"
import "sort"
import "strings"

import repokit "repokit"

type PackageSummary struct {
	Filename string `json:"filename"`
	Name     string `json:"name"`
	Version  string `json:"version"`
	Release  string `json:"release"`
	Arch     string `json:"arch"`
	Summary  string `json:"summary"`
}

type PackageDetail struct {
	PackageSummary
	Description string   `json:"description"`
	License     string   `json:"license"`
	URL         string   `json:"url"`
	BuildTime   int64    `json:"build_time"`
	Size        int64    `json:"size"`
	Files       []string `json:"files"`
	Requires    []string `json:"requires"`
	Provides    []string `json:"provides"`
	Changelogs  []PackageChangeLog `json:"changelogs"`
}

type PackageChangeLog struct {
	Author string `json:"author"`
	Date   int64  `json:"date"`
	Text   string `json:"text"`
}

func ListPackages(repoPath string) ([]PackageSummary, error) {
	var packages []PackageSummary
	var walkErr error
	var err error
	walkErr = filepath.WalkDir(repoPath, func(path string, entry fs.DirEntry, entryErr error) error {
		var lower string
		var rel string
		var pkg *repokit.RpmPackage
		var summary PackageSummary
		if entryErr != nil {
			return entryErr
		}
		if entry.IsDir() {
			return nil
		}
		lower = strings.ToLower(entry.Name())
		if !strings.HasSuffix(lower, ".rpm") {
			return nil
		}
		rel, err = filepath.Rel(repoPath, path)
		if err != nil {
			return err
		}
		pkg, err = repokit.RpmPackageFromRpmBase(path, 0)
		if err != nil {
			return nil
		}
		summary = packageSummaryFromRepokit(pkg, filepath.ToSlash(rel))
		packages = append(packages, summary)
		return nil
	})
	if walkErr != nil {
		return nil, walkErr
	}
	sort.Slice(packages, func(i int, j int) bool {
		if packages[i].Name == packages[j].Name {
			return packages[i].Filename < packages[j].Filename
		}
		return packages[i].Name < packages[j].Name
	})
	return packages, nil
}

func GetPackageDetail(repoPath string, filename string) (PackageDetail, error) {
	var detail PackageDetail
	var fullPath string
	var pkg *repokit.RpmPackage
	var err error
	fullPath = filepath.Join(repoPath, filepath.FromSlash(filename))
	pkg, err = repokit.RpmPackageFromRpmBase(fullPath, 256)
	if err != nil {
		return detail, err
	}
	detail = packageDetailFromRepokit(pkg, filename)
	return detail, nil
}

func packageSummaryFromRepokit(pkg *repokit.RpmPackage, filename string) PackageSummary {
	var summary PackageSummary
	summary = PackageSummary{
		Filename: filename,
		Name:     strings.TrimSpace(pkg.Name),
		Version:  strings.TrimSpace(pkg.Version),
		Release:  strings.TrimSpace(pkg.Release),
		Arch:     strings.TrimSpace(pkg.Arch),
		Summary:  strings.TrimSpace(pkg.Summary),
	}
	return summary
}

func packageDetailFromRepokit(pkg *repokit.RpmPackage, filename string) PackageDetail {
	var files []string
	var file repokit.RpmPackageFile
	var changelogs []PackageChangeLog
	var changelog repokit.RpmChangelogEntry
	var detail PackageDetail
	files = make([]string, 0, len(pkg.Files))
	for _, file = range pkg.Files {
		if file.FullPath == "" {
			continue
		}
		files = append(files, file.FullPath)
	}
	changelogs = make([]PackageChangeLog, 0, len(pkg.Changelogs))
	for _, changelog = range pkg.Changelogs {
		changelogs = append(changelogs, PackageChangeLog{
			Author: strings.TrimSpace(changelog.Author),
			Date:   changelog.Date,
			Text:   strings.TrimSpace(changelog.Changelog),
		})
	}
	sort.SliceStable(changelogs, func(i int, j int) bool {
		return changelogs[i].Date > changelogs[j].Date
	})
	sort.Strings(files)
	detail = PackageDetail{
		PackageSummary: packageSummaryFromRepokit(pkg, filename),
		Description:    strings.TrimSpace(pkg.Description),
		License:        strings.TrimSpace(pkg.RpmLicense),
		URL:            strings.TrimSpace(pkg.Url),
		BuildTime:      pkg.TimeBuild,
		Size:           pkg.SizePackage,
		Files:          files,
		Requires:       dependencyListToStrings(pkg.Requires),
		Provides:       dependencyListToStrings(pkg.Provides),
		Changelogs:     changelogs,
	}
	return detail
}

func dependencyListToStrings(deps []repokit.RpmDependency) []string {
	var lines []string
	var dep repokit.RpmDependency
	lines = make([]string, 0, len(deps))
	for _, dep = range deps {
		lines = append(lines, dependencyToString(dep))
	}
	return lines
}

func dependencyToString(dep repokit.RpmDependency) string {
	var op string
	var evr string
	var line string
	op = normalizeDependencyOp(dep.Flags)
	evr = dependencyEVR(dep)
	line = dep.Name
	if op == "" || evr == "" {
		return line
	}
	line = line + " " + op + " " + evr
	return line
}

func normalizeDependencyOp(flag string) string {
	switch strings.ToUpper(strings.TrimSpace(flag)) {
	case "LT":
		return "<"
	case "GT":
		return ">"
	case "EQ":
		return "="
	case "LE":
		return "<="
	case "GE":
		return ">="
	default:
		return strings.TrimSpace(flag)
	}
}

func dependencyEVR(dep repokit.RpmDependency) string {
	var value string
	var version string
	version = strings.TrimSpace(dep.Version)
	if version == "" {
		return ""
	}
	value = version
	if strings.TrimSpace(dep.Release) != "" {
		value = value + "-" + strings.TrimSpace(dep.Release)
	}
	if strings.TrimSpace(dep.Epoch) != "" && strings.TrimSpace(dep.Epoch) != "0" {
		value = strings.TrimSpace(dep.Epoch) + ":" + value
	}
	return value
}