package common

import (
	"crypto/hmac"
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"sort"

	"golang.org/x/exp/maps"

	"fmt"
	"net/url"
	"strings"
	"time"

	cfg "github.com/alibaba/higress/plugins/wasm-go/extensions/ai-security-guard/config"
	"github.com/google/uuid"
)

const (
	ALGORITHM = "ACS3-HMAC-SHA256"
)

type Request struct {
	httpMethod   string
	canonicalUri string
	host         string
	xAcsAction   string
	xAcsVersion  string
	headers      map[string]string
	body         []byte
	queryParam   map[string]interface{}
}

func newRequest(httpMethod, canonicalUri, host, xAcsAction, xAcsVersion string) *Request {
	req := &Request{
		httpMethod:   httpMethod,
		canonicalUri: canonicalUri,
		host:         host,
		xAcsAction:   xAcsAction,
		xAcsVersion:  xAcsVersion,
		headers:      make(map[string]string),
		queryParam:   make(map[string]interface{}),
	}
	req.headers["host"] = host
	req.headers["x-acs-action"] = xAcsAction
	req.headers["x-acs-version"] = xAcsVersion
	req.headers["x-acs-date"] = time.Now().UTC().Format(time.RFC3339)
	req.headers["x-acs-signature-nonce"] = uuid.New().String()
	return req
}

func getAuthorization(req *Request, AccessKeyId, AccessKeySecret, SecurityToken string) {
	newQueryParams := make(map[string]interface{})
	processObject(newQueryParams, "", req.queryParam)
	req.queryParam = newQueryParams
	canonicalQueryString := ""
	keys := maps.Keys(req.queryParam)
	sort.Strings(keys)
	for _, k := range keys {
		v := req.queryParam[k]
		canonicalQueryString += percentCode(url.QueryEscape(k)) + "=" + percentCode(url.QueryEscape(fmt.Sprintf("%v", v))) + "&"
	}
	canonicalQueryString = strings.TrimSuffix(canonicalQueryString, "&")

	var bodyContent []byte
	if req.body == nil {
		bodyContent = []byte("")
	} else {
		bodyContent = req.body
	}
	hashedRequestPayload := sha256Hex(bodyContent)
	req.headers["x-acs-content-sha256"] = hashedRequestPayload

	if SecurityToken != "" {
		req.headers["x-acs-security-token"] = SecurityToken
	}

	canonicalHeaders := ""
	signedHeaders := ""
	HeadersKeys := maps.Keys(req.headers)
	sort.Strings(HeadersKeys)
	for _, k := range HeadersKeys {
		lowerKey := strings.ToLower(k)
		if lowerKey == "host" || strings.HasPrefix(lowerKey, "x-acs-") || lowerKey == "content-type" {
			canonicalHeaders += lowerKey + ":" + req.headers[k] + "\n"
			signedHeaders += lowerKey + ";"
		}
	}
	signedHeaders = strings.TrimSuffix(signedHeaders, ";")

	canonicalRequest := req.httpMethod + "\n" + req.canonicalUri + "\n" + canonicalQueryString + "\n" + canonicalHeaders + "\n" + signedHeaders + "\n" + hashedRequestPayload

	hashedCanonicalRequest := sha256Hex([]byte(canonicalRequest))
	stringToSign := ALGORITHM + "\n" + hashedCanonicalRequest

	byteData, err := hmac256([]byte(AccessKeySecret), stringToSign)
	if err != nil {
		fmt.Println(err)
		panic(err)
	}
	signature := strings.ToLower(hex.EncodeToString(byteData))

	authorization := ALGORITHM + " Credential=" + AccessKeyId + ",SignedHeaders=" + signedHeaders + ",Signature=" + signature
	req.headers["Authorization"] = authorization
}

func hmac256(key []byte, toSignString string) ([]byte, error) {
	h := hmac.New(sha256.New, key)
	_, err := h.Write([]byte(toSignString))
	if err != nil {
		return nil, err
	}
	return h.Sum(nil), nil
}

func sha256Hex(byteArray []byte) string {
	hash := sha256.New()
	_, _ = hash.Write(byteArray)
	hexString := hex.EncodeToString(hash.Sum(nil))
	return hexString
}

func percentCode(str string) string {
	str = strings.ReplaceAll(str, "+", "%20")
	str = strings.ReplaceAll(str, "*", "%2A")
	str = strings.ReplaceAll(str, "%7E", "~")
	return str
}

func formDataToString(formData map[string]interface{}) *string {
	tmp := make(map[string]interface{})
	processObject(tmp, "", formData)
	res := ""
	urlEncoder := url.Values{}
	for key, value := range tmp {
		v := fmt.Sprintf("%v", value)
		urlEncoder.Add(key, v)
	}
	res = urlEncoder.Encode()
	return &res
}

// processObject 递归处理对象，将复杂对象（如Map和List）展开为平面的键值对
func processObject(mapResult map[string]interface{}, key string, value interface{}) {
	if value == nil {
		return
	}

	switch v := value.(type) {
	case []interface{}:
		for i, item := range v {
			processObject(mapResult, fmt.Sprintf("%s.%d", key, i+1), item)
		}
	case map[string]interface{}:
		for subKey, subValue := range v {
			processObject(mapResult, fmt.Sprintf("%s.%s", key, subKey), subValue)
		}
	default:
		if strings.HasPrefix(key, ".") {
			key = key[1:]
		}
		if b, ok := v.([]byte); ok {
			mapResult[key] = string(b)
		} else {
			mapResult[key] = fmt.Sprintf("%v", v)
		}
	}
}

func GenerateRequestForText(config cfg.AISecurityConfig, checkAction, checkService, text, sessionID string) (path string, headers [][2]string, reqBody []byte) {
	httpMethod := "POST"
	canonicalUri := "/"
	xAcsVersion := "2022-03-02"
	req := newRequest(httpMethod, canonicalUri, config.Host, checkAction, xAcsVersion)

	req.queryParam["Service"] = checkService

	body := make(map[string]interface{})
	serviceParameters := make(map[string]interface{})
	serviceParameters["content"] = text
	serviceParameters["sessionId"] = sessionID
	serviceParameters["requestFrom"] = cfg.AliyunUserAgent
	serviceParametersJSON, _ := json.Marshal(serviceParameters)
	body["ServiceParameters"] = serviceParametersJSON
	str := formDataToString(body)
	req.body = []byte(*str)
	req.headers["content-type"] = "application/x-www-form-urlencoded"
	req.headers["User-Agent"] = cfg.AliyunUserAgent

	getAuthorization(req, config.AK, config.SK, config.Token)

	q := url.Values{}
	keys := maps.Keys(req.queryParam)
	sort.Strings(keys)
	for _, k := range keys {
		v := req.queryParam[k]
		q.Set(k, fmt.Sprintf("%v", v))
	}
	for k, v := range req.headers {
		if k != "host" {
			headers = append(headers, [2]string{k, v})
		}
	}
	return "?" + q.Encode(), headers, req.body
}

func GenerateRequestForImage(config cfg.AISecurityConfig, checkAction, checkService, imgUrl, imgBase64 string) (path string, headers [][2]string, reqBody []byte) {
	httpMethod := "POST"
	canonicalUri := "/"
	xAcsVersion := "2022-03-02"
	req := newRequest(httpMethod, canonicalUri, config.Host, checkAction, xAcsVersion)

	req.queryParam["Service"] = checkService

	body := make(map[string]interface{})
	serviceParameters := make(map[string]interface{})
	if imgUrl != "" {
		serviceParameters["imageUrls"] = []string{imgUrl}
	}
	serviceParameters["requestFrom"] = cfg.AliyunUserAgent
	serviceParametersJSON, _ := json.Marshal(serviceParameters)
	body["ServiceParameters"] = serviceParametersJSON
	if imgBase64 != "" {
		body["ImageBase64Str"] = imgBase64
	}
	str := formDataToString(body)
	req.body = []byte(*str)
	req.headers["content-type"] = "application/x-www-form-urlencoded"
	req.headers["User-Agent"] = cfg.AliyunUserAgent

	getAuthorization(req, config.AK, config.SK, config.Token)

	q := url.Values{}
	keys := maps.Keys(req.queryParam)
	sort.Strings(keys)
	for _, k := range keys {
		v := req.queryParam[k]
		q.Set(k, fmt.Sprintf("%v", v))
	}
	for k, v := range req.headers {
		// host will be added by envoy automatically
		if k != "host" {
			headers = append(headers, [2]string{k, v})
		}
	}
	return "?" + q.Encode(), headers, req.body
}