package fontinfo

import (
	"fmt"
	"io/fs"
	"os"
	"os/user"
	"path/filepath"
	"strings"
)

// Font represents a font file on disk
type Font struct {
	Family string
	Style  string
	Path   string
}

var validExtensions = map[string]FontParser{
	".ttf": &TruetypeParser{},
	".otf": &TruetypeParser{},
	//".bdf": &TruetypeParser{},
	//".pcf": &TruetypeParser{},
}

var fontDirs = []string{
	"~/.fonts",
	"~/.local/share/fonts",
	"/usr/local/share/fonts",
	"/usr/share/fonts",
	filepath.Join(os.Getenv("XDG_DATA_HOME"), "fonts"),
}

func init() {
	dataDirs := strings.Split(os.Getenv("XDG_DATA_DIRS"), string(os.PathListSeparator))
	for _, dir := range dataDirs {
		if dir == "" {
			continue
		}
		fontDirs = append(fontDirs, filepath.Join(dir, "fonts"))
	}
}

// Match finds all fonts installed on the system which match the provided matchers
func Match(matchers ...Matcher) ([]Font, error) {

	var fonts []Font
	meta := make(map[string]*FontMetadata)

	var home string
	if usr, _ := user.Current(); usr != nil {
		home = usr.HomeDir
	}

	for _, dir := range fontDirs {
		if home != "" && strings.HasPrefix(dir, "~/") {
			dir = filepath.Join(home, dir[2:])
		}
		if info, err := os.Stat(dir); os.IsNotExist(err) {
			continue
		} else if !info.IsDir() {
			continue
		}
		err := filepath.WalkDir(dir, func(path string, info fs.DirEntry, err error) error {
			if _, ok := meta[path]; ok {
				return nil
			}
			ext := filepath.Ext(path)
			if parser, ok := validExtensions[strings.ToLower(ext)]; ok {
				f, err := os.Open(path)
				if err != nil {
					return err
				}
				defer f.Close()
				metadata, err := parser.Parse(f)
				if err != nil {
					fmt.Printf("could not parse %s: %s\n", path, err)
					return nil
				}
				for _, match := range matchers {
					if match(metadata) {
						meta[path] = metadata
						break
					}
				}
				return nil
			}
			return nil
		})
		if err != nil {
			return nil, err
		}
	}
	for path, metadata := range meta {
		fonts = append(fonts, Font{
			Family: metadata.FontFamily,
			Style:  metadata.FontStyle,
			Path:   path,
		})
	}

	return fonts, nil
}