package logic

import (
	"context"
	"crypto/hmac"
	"crypto/sha256"
	"encoding/base64"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"hash"
	"io"
	"time"

	"lone-services/pkg/utils"
	chore "lone-services/rpc/chore/pb"
	"lone-services/services/chore/internal/svc"

	"github.com/aliyun/credentials-go/credentials"
	"github.com/zeromicro/go-zero/core/logx"
)

type PolicyLogic struct {
	ctx    context.Context
	svcCtx *svc.ServiceContext
	logx.Logger
}

type PolicyToken struct {
	Policy           string `json:"policy"`
	SecurityToken    string `json:"security_token"`
	SignatureVersion string `json:"x_oss_signature_version"`
	Credential       string `json:"x_oss_credential"`
	Date             string `json:"x_oss_date"`
	Signature        string `json:"signature"`
	Host             string `json:"host"`
	Dir              string `json:"dir"`
}

func NewPolicyLogic(ctx context.Context, svcCtx *svc.ServiceContext) *PolicyLogic {
	return &PolicyLogic{
		ctx:    ctx,
		svcCtx: svcCtx,
		Logger: logx.WithContext(ctx),
	}
}

var (
	region     string
	bucketName string
	product    = "oss"
)

func (l *PolicyLogic) Policy(in *chore.PolicyReq) (*chore.Response, error) {
	// 设置bucket所处地域
	region = utils.GetConfigString("oss.region")
	// 替换为您的bucket名称
	bucketName = utils.GetConfigString("oss.bucketName")
	// 设置 OSS 上传地址
	// lone-images.oss-accelerate.aliyuncs.com
	host := fmt.Sprintf("https://%s.oss-%s.aliyuncs.com", bucketName, region)
	// 设置上传目录
	dir := utils.GetConfigString("oss.dir")
	config := new(credentials.Config).
		SetType("ram_role_arn").
		SetAccessKeyId(utils.GetConfigString("oss.accessKeyId")).
		SetAccessKeySecret(utils.GetConfigString("oss.accessKeySecret")).
		SetRoleArn(utils.GetConfigString("oss.roleArn")).
		SetRoleSessionName(utils.GetConfigString("oss.roleSessionName")).
		SetPolicy("").
		SetRoleSessionExpiration(3600)

	// 根据配置创建凭证提供器
	provider, err := credentials.NewCredential(config)
	if err != nil {
		l.Errorf("NewCredential fail, err:%v", err)
	}
	// 从凭证提供器获取凭证
	cred, err := provider.GetCredential()
	if err != nil {
		l.Errorf("GetCredential fail, err:%v", err)
	}
	// 构建policy
	utcTime := time.Now().UTC()
	date := utcTime.Format("20060102")
	expiration := utcTime.Add(1 * time.Hour)
	policyMap := map[string]any{
		"expiration": expiration.Format("2006-01-02T15:04:05.000Z"),
		"conditions": []any{
			map[string]string{"bucket": bucketName},
			map[string]string{"x-oss-signature-version": "OSS4-HMAC-SHA256"},
			map[string]string{"x-oss-credential": fmt.Sprintf("%v/%v/%v/%v/aliyun_v4_request", *cred.AccessKeyId, date, region, product)},
			map[string]string{"x-oss-date": utcTime.Format("20060102T150405Z")},
			map[string]string{"x-oss-security-token": *cred.SecurityToken},
		},
	}
	// 将policy转换为 JSON 格式
	policy, err := json.Marshal(policyMap)
	if err != nil {
		l.Errorf("json.Marshal fail, err:%v", err)
	}
	// 构造待签名字符串（StringToSign）
	stringToSign := base64.StdEncoding.EncodeToString([]byte(policy))
	hmacHash := func() hash.Hash { return sha256.New() }
	// 构建signing key
	signingKey := "aliyun_v4" + *cred.AccessKeySecret
	h1 := hmac.New(hmacHash, []byte(signingKey))
	io.WriteString(h1, date)
	h1Key := h1.Sum(nil)
	h2 := hmac.New(hmacHash, h1Key)
	io.WriteString(h2, region)
	h2Key := h2.Sum(nil)
	h3 := hmac.New(hmacHash, h2Key)
	io.WriteString(h3, product)
	h3Key := h3.Sum(nil)
	h4 := hmac.New(hmacHash, h3Key)
	io.WriteString(h4, "aliyun_v4_request")
	h4Key := h4.Sum(nil)
	// 生成签名
	h := hmac.New(hmacHash, h4Key)
	io.WriteString(h, stringToSign)
	signature := hex.EncodeToString(h.Sum(nil))
	// 构建返回给前端的表单
	policyToken := PolicyToken{
		Policy:           stringToSign,
		SecurityToken:    *cred.SecurityToken,
		SignatureVersion: "OSS4-HMAC-SHA256",
		Credential:       fmt.Sprintf("%v/%v/%v/%v/aliyun_v4_request", *cred.AccessKeyId, date, region, product),
		Date:             utcTime.UTC().Format("20060102T150405Z"),
		Signature:        signature,
		Host:             host, // 返回 OSS 上传地址
		Dir:              dir,  // 返回上传目录
	}
	response, err := json.Marshal(policyToken)
	if err != nil {
		fmt.Println("json err:", err)
	}
	return &chore.Response{
		Code: 0,
		Data: string(response),
	}, nil
}