package doodle

import (
	"fmt"
	"os"
	"path/filepath"
	"regexp"
	"runtime"
	"strings"

	"git.kirsle.net/SketchyMaze/doodle/assets"
	"git.kirsle.net/SketchyMaze/doodle/pkg/log"
	"git.kirsle.net/SketchyMaze/doodle/pkg/userdir"
)

// Regexp to match simple filenames for maps and doodads.
var reSimpleFilename = regexp.MustCompile(`^([A-Za-z0-9-_.,+ '"\[\](){}]+)$`)

/*
EditFile opens a drawing file (Level or Doodad) in the EditorScene.

The filename can be one of the following:

  - A simple filename with no path separators in it and/or no file extension.
  - An absolute path beginning with "/"
  - A relative path beginning with "./"

If the filename has an extension (`.level` or `.doodad`), that will disambiguate
how to find the file and which mode to start the EditorMode in. Otherwise, the
"levels" folder is checked first and the "doodads" folder second.
*/
func (d *Doodle) EditFile(filename string) error {
	var absPath string

	// Is it a simple filename?
	if m := reSimpleFilename.FindStringSubmatch(filename); len(m) > 0 {
		log.Debug("EditFile: simple filename %s", filename)
		extension := strings.ToLower(filepath.Ext(filename))

		// Check the system level storage. TODO: no editing of system levels
		if _, err := assets.Asset("assets/levels/" + filename); err == nil {
			log.Info("Found level %s in bindata", filename)
			return d.EditDrawing(filename)
		}

		// Check the user's levels directory. In WASM this will check in
		// localStorage.
		if foundFilename := userdir.ResolvePath(filename, extension, false); foundFilename != "" {
			log.Info("EditFile: resolved name '%s' to path %s", filename, foundFilename)
			absPath = foundFilename
		} else {
			return fmt.Errorf("EditFile: %s: no level or doodad found", filename)
		}

	} else {
		log.Debug("Not a simple: %s %+v", filename, reSimpleFilename)

		// WASM: no filesystem access.
		if runtime.GOOS == "js" {
			log.Error("EditFile(%s): wasm can't open file paths", filename)
			return fmt.Errorf("EditFile(%s): wasm can't open file paths", filename)
		}

		if _, err := os.Stat(filename); !os.IsNotExist(err) {
			log.Debug("EditFile: verified path %s exists", filename)
			absPath = filename
		}
	}

	return d.EditDrawing(absPath)
}