// Copyright 2021 Liuxiangchao iwind.liu@gmail.com. All rights reserved.
//go:build script
// +build script

package js

import (
	"crypto/hmac"
	"crypto/md5"
	"crypto/sha1"
	"crypto/sha256"
	"crypto/sha512"
	"errors"
	"fmt"
	teaconst "github.com/TeaOSLab/EdgeNode/internal/const"
	"hash"
)

func init() {
	if !teaconst.IsMain {
		return
	}

	SharedLibraryManager.Register(&JSHMACCryptoLibrary{})
}

type JSHMACCryptoLibrary struct {
	JSBaseLibrary
}

func (this *JSHMACCryptoLibrary) JSNamespace() string {
	return "gojs.crypto.JSHMACLibrary"
}

func (this *JSHMACCryptoLibrary) JSPrototype() string {
	return `gojs.crypto.HMAC = class {
	#goObjectId

	constructor(algorithm, key) {
		this.#goObjectId = $this.NewHMAC(algorithm, key)
	}

	update(data) {
		$this.Update(this.#goObjectId, data)
	}
	
	sum() {
		return $this.Sum(this.#goObjectId)
	}
}`
}

func (this *JSHMACCryptoLibrary) NewHMAC(arguments *FunctionArguments) (any, error) {
	algorithm, ok := arguments.StringAt(0)
	if !ok {
		return nil, errors.New("require hash algorithm")
	}

	key, ok := arguments.StringAt(1)
	if !ok {
		return nil, errors.New("require hash key")
	}

	var h hash.Hash
	switch algorithm {
	case "md5":
		h = hmac.New(md5.New, []byte(key))
	case "sha1":
		h = hmac.New(sha1.New, []byte(key))
	case "sha256":
		h = hmac.New(sha256.New, []byte(key))
	case "sha512":
		h = hmac.New(sha512.New, []byte(key))
	default:
		return nil, errors.New("invalid hash algorithm")
	}

	return arguments.Context().AddGoObject(h), nil
}

func (this *JSHMACCryptoLibrary) Update(arguments *FunctionArguments) (any, error) {
	obj, ok := arguments.GoObjectAt(0)
	if !ok {
		return nil, ErrGoObjectNotFound
	}

	data, ok := arguments.FormatStringAt(1)
	if !ok {
		return nil, errors.New("invalid data")
	}

	h, ok := obj.(hash.Hash)
	if !ok {
		return nil, errors.New("invalid hash")
	}

	h.Reset()
	h.Write([]byte(data))

	return nil, nil
}

func (this *JSHMACCryptoLibrary) Sum(arguments *FunctionArguments) (any, error) {
	obj, ok := arguments.GoObjectAt(0)
	if !ok {
		return nil, ErrGoObjectNotFound
	}

	h, ok := obj.(hash.Hash)
	if !ok {
		return nil, errors.New("invalid hash")
	}

	return fmt.Sprintf("%x", h.Sum(nil)), nil
}