# Not unlike factory pattern.

# This code's been directly written in due to time and lazy, but
# will be thrown into submodules eventually to clean readability up.

## Recursively creates virtual file systems.
static func create_meta_accessor(file_accessors:Array[VFileAccess])->VFileAccess:
	var vfiler := VFileAccess.new()
	
	vfiler._get_stuff = func()->Variant: return file_accessors
	
	vfiler._file_exists = func(path:String)->bool:
		return file_accessors.any(func(vfs:VFileAccess)->bool:
			return vfs.file_exists(path))
	
	vfiler._get_files_at = func(path:String)->Array[String]:
		var accum:Array[String] = []
		accum.assign(
			file_accessors.reduce(
				(func _merge_files(total:Array[String], current:VFileAccess)->Array[String]:
					var res:Array[String] = total.duplicate()
					for file:String in current.get_files_at(path):
						if not file in total:
							res.append(file)
					return res) ,[]))
		return accum
	
	vfiler._get_buffer = func(path:String)->PackedByteArray:
		for vfs:VFileAccess in file_accessors:
			if vfs.file_exists(path):
				return vfs.get_buffer(path)
		push_error("File '%s' not found in any checked accessors." % path)
		return PackedByteArray()
	
	vfiler._write_file = func _zip_write(_path:String, _buffer:PackedByteArray)->Error:
		return ERR_FILE_CANT_WRITE
	
	vfiler._close = func()->void:
		file_accessors.map(func(vfs:VFileAccess)->void: vfs.close())
	
	return vfiler


## A basic file accessor.
static func create_file_access(
		root:String = "./",
		support_files:Dictionary[String,Callable] = VFileAccess.IMPORTS.DEFAULT_SUPPORTED_FILES
	)->VFileAccess:
	var vfiler := VFileAccess.new(root, support_files)
	
	vfiler._get_buffer = FileAccess.get_file_as_bytes	# thanks for being static
	
	vfiler._file_exists = FileAccess.file_exists		# thanks for being static
	
	vfiler._write_file = func _file_access_write(path:String, buffer:PackedByteArray)->void:
		var abs_path := vfiler.get_absolute_path(path)
		if not DirAccess.dir_exists_absolute(abs_path):
			DirAccess.make_dir_recursive_absolute(abs_path.get_base_dir())
		var f := FileAccess.open(abs_path, FileAccess.WRITE_READ)
		f.store_buffer(buffer)
		f.close()
	
	vfiler._get_files_at = func(path:String)->Array[String]:
		var paths:Array[String] = []
		#var abs_path := vfiler.get_absolute_path(path)
		if not DirAccess.dir_exists_absolute(path):
			print("Path '%s' not found. Adding..." % path)
			DirAccess.make_dir_recursive_absolute(path)
		paths.assign(DirAccess.get_files_at(path))
		return paths
	
	return vfiler


static func create_writeonly_zip_access(
		zip_path:String,
		append := ZIPPacker.ZipAppend.APPEND_CREATE,
	)->VFileAccess:
	var vfiler := VFileAccess.new()
	if not is_instance_valid(vfiler): return null
	
	var writer := ZIPPacker.new()	
	# Open once to verify it exists and works.
	var _open_err := writer.open(zip_path, append)
	#if open_err != OK:
		#push_error("Could not open zip writer '%s'" % error_string(open_err))
		#return null
	#writer.close()
	
	vfiler._get_stuff = func()->Variant: return writer
	
	vfiler._write_file = func _zip_write(path:String, buffer:PackedByteArray)->Error:
		var abs_path := vfiler.get_absolute_path(path)
		writer.start_file(path)
		var write_err := writer.write_file(buffer)
		writer.close_file()
		return write_err
	
	vfiler._get_buffer = func(_path:String)->PackedByteArray:
		push_error("Attempted to read from write-only zip access! Returning 0 bytes.")
		return PackedByteArray()
	
	vfiler._get_files_at = func(_path:String)->Array[String]:
		push_error("Attempted to get files from write-only zip access!")
		return []
	
	vfiler._close = func()->void: writer.close()
	
	return vfiler



## A single zip file accessor, but with write functions disabled.
## TODO option to keep zips open, for OS to flag files as in-use.
static func create_readonly_zip_access(
		zip_path:String, keep_open:bool = false,
		support_files:Dictionary[String,Callable] = VFileAccess.IMPORTS.DEFAULT_SUPPORTED_FILES
	)->VFileAccess:
	var vfiler := create_bulk_readonly_zip_access([zip_path], keep_open, support_files)
	vfiler._get_stuff = func()->Variant: return vfiler.get_stuff()[0]
	return vfiler

## A multi-zip readonly accessor. Allows for multiple zips to load with overrides.
## TODO option to keep zips open, for OS to flag files as in-use.
## [param if_missing_zip(String)] executes if a requested file is not found.
static func create_bulk_readonly_zip_access(
		zip_paths:Array[String], keep_open:bool = false,
		support_files:Dictionary[String,Callable] = VFileAccess.IMPORTS.DEFAULT_SUPPORTED_FILES,
		if_missing_zip := func _ignore(_zip_path:String)->bool: return false,
	)->VFileAccess:
	var vfiler := VFileAccess.new("", support_files)
	
	var readers:Array[ZIPReader] = []
	readers.assign(zip_paths.map(
		func _open_zip_reader(zip_path:String)->ZIPReader:
			var zip := ZIPReader.new()
			if not FileAccess.file_exists(zip_path):	# Use VFileAccess recursively so we are more powerful?
				if_missing_zip.call(zip_path)
			var open_err := zip.open(zip_path)
			if open_err:
				push_error("Could not open zip '%s': %s" % [zip_path, error_string(open_err)])
				return null
			return zip))
	
	readers.assign(readers.filter(is_instance_valid))
	
	vfiler._get_stuff = func()->Variant: return readers
	
	# file exists set first so we can bulk-check later
	vfiler._file_exists = func(abs_path:String)->bool:
		return readers.any(
			func(z:ZIPReader)->bool: return z.file_exists(abs_path))
	
	vfiler._get_buffer = func(abs_path:String)->PackedByteArray:
		var output := PackedByteArray()
		if not vfiler.file_exists(abs_path):
			push_error("Zips don't have file id '%s'" % abs_path)
			return output
		for index:int in readers.size():
			var z := readers[index]
			if not z.file_exists(abs_path):	continue
			output = z.read_file(abs_path)
			break
		return output
	
	vfiler._write_file = func _zip_write(_path:String, _buffer:PackedByteArray)->Error:
		return ERR_FILE_CANT_WRITE
	vfiler._close = func()->void:
		readers.map(func(z:ZIPReader)->void: z.close())
	
	vfiler._get_files_at = func(path:String)->Array[String]:
		if not path.ends_with("/"):		# TODO ensure no // as well because that can be problem.
			path += "/"					# sorry for the mutation
		var accum:Array[String] = []
		accum.assign(	readers.reduce(
			(func _merge_files(total:Array[String], current:ZIPReader)->Array[String]:
				var res:Array[String] = total.duplicate()
				var filtered:Array = []
				filtered.assign(current.get_files())
				filtered.filter(
					func _filter_dir(curpath:String)->bool:
						return curpath.begins_with(path))
				for file:String in filtered:
					var stripped_file:String = file.replace(path, "")
					# remove files with / after the file stripping to prevent directories.
					if not file in total and not stripped_file.contains("/"):
						res.append(file)
				return res) ,[]))
		return accum
	
	return vfiler