package usecase

import (
	"context"
	"fmt"
	"strconv"
	"time"

	"backend/internal/config"
	"backend/pkg/library/errs"
	"backend/pkg/library/errs/code"
	"backend/pkg/permission/domain/entity"
	"backend/pkg/permission/domain/repository"
	"backend/pkg/permission/domain/token"
	"backend/pkg/permission/domain/usecase"

	"github.com/segmentio/ksuid"
	"github.com/zeromicro/go-zero/core/logx"
)

type TokenUseCaseParam struct {
	TokenRepo repository.TokenRepository

	Config *config.Config
}

type TokenUseCase struct {
	TokenUseCaseParam
}

func (use *TokenUseCase) ReadTokenBasicData(ctx context.Context, token string) (map[string]string, error) {
	claims, err := parseClaims(token, use.Config.Token.AccessSecret, false)
	if err != nil {
		return nil,
			use.wrapTokenError(ctx, wrapTokenErrorReq{
				funcName:  "parseClaims",
				req:       token,
				err:       err,
				message:   "validate token claims error",
				errorCode: code.TokenValidateError,
			})
	}

	return claims, nil
}

func MustTokenUseCase(param TokenUseCaseParam) usecase.TokenUseCase {
	return &TokenUseCase{
		param,
	}
}

// ============================================ token ============================================

func (use *TokenUseCase) NewToken(ctx context.Context, req entity.AuthorizationReq) (entity.TokenResp, error) {
	tokenObj, err := use.newToken(ctx, &req)
	if err != nil {
		return entity.TokenResp{}, err
	}

	err = use.TokenRepo.Create(ctx, *tokenObj)
	if err != nil {
		return entity.TokenResp{}, use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "TokenRepo.Create",
			req:       req,
			err:       err,
			message:   "failed to create token",
			errorCode: code.TokenCreateError,
		})
	}

	return entity.TokenResp{
		AccessToken:  tokenObj.AccessToken,
		TokenType:    token.TypeBearer.String(),
		ExpiresIn:    int64(tokenObj.ExpiresIn),
		RefreshToken: tokenObj.RefreshToken,
	}, nil
}

func (use *TokenUseCase) newToken(ctx context.Context, req *entity.AuthorizationReq) (*entity.Token, error) {
	// 準備建立 Token 所需
	now := time.Now().UTC()
	expires := req.Expires
	refreshExpires := req.Expires

	if expires <= 0 {
		// 將時間加上 n 秒
		sec := use.Config.Token.AccessTokenExpiry
		// 獲取 Unix 時間戳
		expires = now.Add(sec).Unix()
		refreshExpires = expires
	}

	// 如果這是一個 Refresh Token 過期時間要比普通的Token 長
	if req.IsRefreshToken {
		// 獲取 Unix 時間戳
		refresh := use.Config.Token.RefreshTokenExpiry
		refreshExpires = now.Add(refresh).Unix()
	}

	token := entity.Token{
		ID:               ksuid.New().String(),
		DeviceID:         req.DeviceID,
		ExpiresIn:        int(expires),
		RefreshExpiresIn: int(refreshExpires),
		AccessCreateAt:   now,
		RefreshCreateAt:  now,
	}

	tc := make(tokenClaims)
	if req.Data != nil {
		for k, v := range req.Data {
			tc[k] = v
		}
	}
	tc.SetRole(req.Role)
	tc.SetID(token.ID)
	tc.SetScope(req.Scope)
	tc.SetAccount(req.Account)

	token.UID = tc.UID()

	if req.DeviceID != "" {
		tc.SetDeviceID(req.DeviceID)
	}

	var err error
	token.AccessToken, err = accessTokenGenerator(token, tc, use.Config.Token.AccessSecret)
	if err != nil {
		return nil, use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "accessTokenGenerator",
			req:       req,
			err:       err,
			message:   "failed to generator access token",
			errorCode: code.TokenCreateError,
		})
	}

	if req.IsRefreshToken {
		token.RefreshToken = refreshTokenGenerator(token.AccessToken)
	}

	return &token, nil
}

func (use *TokenUseCase) RefreshToken(ctx context.Context, req entity.RefreshTokenReq) (entity.RefreshTokenResp, error) {
	// Step 1: 檢查 refresh token
	tokenObj, err := use.TokenRepo.GetAccessTokenByOneTimeToken(ctx, req.Token)
	if err != nil {
		return entity.RefreshTokenResp{},
			use.wrapTokenError(ctx, wrapTokenErrorReq{
				funcName:  "TokenRepo.GetAccessTokenByOneTimeToken",
				req:       req,
				err:       err,
				message:   "failed to get access token",
				errorCode: code.TokenValidateError,
			})
	}

	// Step 2: 提取 Claims Data
	claimsData, err := parseClaims(tokenObj.AccessToken, use.Config.Token.AccessSecret, false)
	if err != nil {
		return entity.RefreshTokenResp{},
			use.wrapTokenError(ctx, wrapTokenErrorReq{
				funcName:  "extractClaims",
				req:       req,
				err:       err,
				message:   "failed to extract claims",
				errorCode: code.TokenValidateError,
			})
	}

	// Step 3: 創建新 token
	credentials := token.ClientCredentials
	newToken, err := use.newToken(ctx, &entity.AuthorizationReq{
		GrantType:      credentials.ToString(),
		Scope:          req.Scope,
		DeviceID:       req.DeviceID,
		Data:           claimsData,
		Expires:        req.Expires,
		IsRefreshToken: true,
		Account:        req.DeviceID,
	})
	if err != nil {
		return entity.RefreshTokenResp{},
			use.wrapTokenError(ctx, wrapTokenErrorReq{
				funcName:  "use.newToken",
				req:       req,
				err:       err,
				message:   "failed to create new token",
				errorCode: code.TokenValidateError,
			})
	}

	if err := use.TokenRepo.Create(ctx, *newToken); err != nil {
		return entity.RefreshTokenResp{},
			use.wrapTokenError(ctx, wrapTokenErrorReq{
				funcName:  "TokenRepo.Create",
				req:       req,
				err:       err,
				message:   "failed to create new token",
				errorCode: code.TokenValidateError,
			})
	}

	// Step 4: 刪除舊 token 並創建新 token
	if err := use.TokenRepo.Delete(ctx, tokenObj); err != nil {
		return entity.RefreshTokenResp{},
			use.wrapTokenError(ctx, wrapTokenErrorReq{
				funcName:  "TokenRepo.Delete",
				req:       req,
				err:       err,
				message:   "failed to delete old token",
				errorCode: code.TokenValidateError,
			})
	}

	// 返回新的 Token 響應
	return entity.RefreshTokenResp{
		Token:        newToken.AccessToken,
		OneTimeToken: newToken.RefreshToken,
		ExpiresIn:    int64(newToken.ExpiresIn),
		TokenType:    token.TypeBearer.String(),
	}, nil
}

func (use *TokenUseCase) CancelToken(ctx context.Context, req entity.CancelTokenReq) error {
	claims, err := parseClaims(req.Token, use.Config.Token.AccessSecret, false)
	if err != nil {
		return use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "CancelToken extractClaims",
			req:       req,
			err:       err,
			message:   "failed to get token claims",
			errorCode: code.TokenValidateError,
		})
	}

	token, err := use.TokenRepo.GetAccessTokenByID(ctx, claims.ID())
	if err != nil {
		return use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "TokenRepo GetAccessTokenByID",
			req:       req,
			err:       err,
			message:   fmt.Sprintf("failed to get token claims :%s", claims.ID()),
			errorCode: code.TokenValidateError,
		})
	}

	err = use.TokenRepo.Delete(ctx, token)
	if err != nil {
		return use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "TokenRepo Delete",
			req:       req,
			err:       err,
			message:   fmt.Sprintf("failed to delete token :%s", token.ID),
			errorCode: code.TokenValidateError,
		})
	}

	return nil
}

func (use *TokenUseCase) ValidationToken(ctx context.Context, req entity.ValidationTokenReq) (entity.ValidationTokenResp, error) {
	claims, err := parseClaims(req.Token, use.Config.Token.AccessSecret, true)
	if err != nil {
		return entity.ValidationTokenResp{},
			use.wrapTokenError(ctx, wrapTokenErrorReq{
				funcName:  "parseClaims",
				req:       req,
				err:       err,
				message:   "validate token claims error",
				errorCode: code.TokenValidateError,
			})
	}

	token, err := use.TokenRepo.GetAccessTokenByID(ctx, claims.ID())
	if err != nil {
		return entity.ValidationTokenResp{},
			use.wrapTokenError(ctx, wrapTokenErrorReq{
				funcName:  "TokenRepo.GetAccessTokenByID",
				req:       req,
				err:       err,
				message:   fmt.Sprintf("failed to get token :%s", claims.ID()),
				errorCode: code.TokenValidateError,
			})
	}

	return entity.ValidationTokenResp{
		Token: entity.Token{
			ID:               token.ID,
			UID:              token.UID,
			DeviceID:         token.DeviceID,
			AccessCreateAt:   token.AccessCreateAt,
			AccessToken:      token.AccessToken,
			ExpiresIn:        token.ExpiresIn,
			RefreshToken:     token.RefreshToken,
			RefreshExpiresIn: token.RefreshExpiresIn,
			RefreshCreateAt:  token.RefreshCreateAt,
		},
		Data: claims,
	}, nil
}

func (use *TokenUseCase) CancelTokens(ctx context.Context, req entity.DoTokenByUIDReq) error {
	if req.UID != "" {
		err := use.TokenRepo.DeleteAccessTokensByUID(ctx, req.UID)
		if err != nil {
			return use.wrapTokenError(ctx, wrapTokenErrorReq{
				funcName:  "TokenRepo.DeleteAccessTokensByUID",
				req:       req,
				err:       err,
				message:   "failed to cancel tokens by uid",
				errorCode: code.TokenValidateError,
			})
		}
	}

	if len(req.IDs) > 0 {
		err := use.TokenRepo.DeleteAccessTokenByID(ctx, req.IDs)
		if err != nil {
			return use.wrapTokenError(ctx, wrapTokenErrorReq{
				funcName:  "TokenRepo.DeleteAccessTokenByID",
				req:       req,
				err:       err,
				message:   "failed to cancel tokens by token ids",
				errorCode: code.TokenValidateError,
			})
		}
	}

	return nil
}

func (use *TokenUseCase) CancelTokenByDeviceID(ctx context.Context, req entity.DoTokenByDeviceIDReq) error {
	err := use.TokenRepo.DeleteAccessTokensByDeviceID(ctx, req.DeviceID)
	if err != nil {
		return use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "TokenRepo.DeleteAccessTokensByDeviceID",
			req:       req,
			err:       err,
			message:   "failed to cancel token by device id",
			errorCode: code.TokenValidateError,
		})
	}

	return nil
}

func (use *TokenUseCase) GetUserTokensByDeviceID(ctx context.Context, req entity.DoTokenByDeviceIDReq) ([]*entity.TokenResp, error) {
	uidTokens, err := use.TokenRepo.GetAccessTokensByDeviceID(ctx, req.DeviceID)
	if err != nil {
		return nil, use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "TokenRepo.GetAccessTokensByDeviceID",
			req:       req,
			err:       err,
			message:   "failed to get token by device id",
			errorCode: code.TokenNotFound,
		})
	}

	tokens := make([]*entity.TokenResp, 0, len(uidTokens))
	for _, v := range uidTokens {
		tokens = append(tokens, &entity.TokenResp{
			AccessToken:  v.AccessToken,
			TokenType:    token.TypeBearer.String(),
			ExpiresIn:    int64(v.ExpiresIn),
			RefreshToken: v.RefreshToken,
		})
	}

	return tokens, nil
}

func (use *TokenUseCase) GetUserTokensByUID(ctx context.Context, req entity.QueryTokenByUIDReq) ([]*entity.TokenResp, error) {
	uidTokens, err := use.TokenRepo.GetAccessTokensByUID(ctx, req.UID)
	if err != nil {
		return nil, use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "TokenRepo.GetAccessTokensByUID",
			req:       req,
			err:       err,
			message:   "failed to get token by uid",
			errorCode: code.TokenNotFound,
		})
	}

	tokens := make([]*entity.TokenResp, 0, len(uidTokens))
	for _, v := range uidTokens {
		tokens = append(tokens, &entity.TokenResp{
			AccessToken:  v.AccessToken,
			TokenType:    token.TypeBearer.String(),
			ExpiresIn:    int64(v.ExpiresIn),
			RefreshToken: v.RefreshToken,
		})
	}

	return tokens, nil
}

func (use *TokenUseCase) NewOneTimeToken(ctx context.Context, req entity.CreateOneTimeTokenReq) (entity.CreateOneTimeTokenResp, error) {
	// 驗證Token
	claims, err := parseClaims(req.Token, use.Config.Token.AccessSecret, false)
	if err != nil {
		return entity.CreateOneTimeTokenResp{},
			use.wrapTokenError(ctx, wrapTokenErrorReq{
				funcName:  "parseClaims",
				req:       req,
				err:       err,
				message:   "failed to get token claims",
				errorCode: code.OneTimeTokenError,
			})
	}

	tokenObj, err := use.TokenRepo.GetAccessTokenByID(ctx, claims.ID())
	if err != nil {
		return entity.CreateOneTimeTokenResp{},
			use.wrapTokenError(ctx, wrapTokenErrorReq{
				funcName:  "TokenRepo.GetAccessTokenByID",
				req:       req,
				err:       err,
				message:   "failed to get token by id",
				errorCode: code.OneTimeTokenError,
			})
	}

	oneTimeToken := refreshTokenGenerator(ksuid.New().String())
	key := token.TicketKeyPrefix + oneTimeToken
	if err = use.TokenRepo.CreateOneTimeToken(ctx, key, entity.Ticket{
		Data:  claims,
		Token: tokenObj,
	}, time.Minute); err != nil {
		return entity.CreateOneTimeTokenResp{},
			use.wrapTokenError(ctx, wrapTokenErrorReq{
				funcName:  "TokenRepo.CreateOneTimeToken",
				req:       req,
				err:       err,
				message:   "create one time token error",
				errorCode: code.OneTimeTokenError,
			})
	}

	return entity.CreateOneTimeTokenResp{
		OneTimeToken: oneTimeToken,
	}, nil
}

func (use *TokenUseCase) CancelOneTimeToken(ctx context.Context, req entity.CancelOneTimeTokenReq) error {
	err := use.TokenRepo.DeleteOneTimeToken(ctx, req.Token, nil)
	if err != nil {
		return use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "TokenRepo.DeleteOneTimeToken",
			req:       req,
			err:       err,
			message:   "failed to del one time token by token",
			errorCode: code.OneTimeTokenError,
		})
	}

	return nil
}

type wrapTokenErrorReq struct {
	funcName  string
	req       any
	err       error
	message   string
	errorCode uint32
}

// wrapTokenError 將錯誤信息封裝到 errs.LibError 中
func (use *TokenUseCase) wrapTokenError(ctx context.Context, param wrapTokenErrorReq) error {
	logFields := []logx.LogField{
		{Key: "req", Value: param.req},
		{Key: "func", Value: param.funcName},
		{Key: "err", Value: param.err.Error()},
	}
	
	logx.WithContext(ctx).Errorw(param.message, logFields...)
	
	wrappedErr := errs.NewError(
		code.CatToken,
		code.CatToken,
		param.errorCode,
		param.message,
	).Wrap(param.err)

	return wrappedErr
}

// BlacklistToken 將 JWT token 加入黑名單 (立即撤銷)
func (use *TokenUseCase) BlacklistToken(ctx context.Context, token string, reason string) error {
	// 解析 JWT 獲取完整的 claims
	claimMap, err := parseToken(token, use.Config.Token.AccessSecret, false)
	if err != nil {
		return use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "BlacklistToken.parseToken",
			req:       token,
			err:       err,
			message:   "failed to parse token claims",
			errorCode: code.InvalidJWT,
		})
	}

	// 獲取 JTI (JWT ID)
	jti, exists := claimMap["jti"]
	if !exists {
		return use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "BlacklistToken.getJTI",
			req:       token,
			err:       entity.ErrInvalidJTI,
			message:   "token missing JTI claim",
			errorCode: code.InvalidJWT,
		})
	}

	jtiStr, ok := jti.(string)
	if !ok {
		return use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "BlacklistToken.convertJTI",
			req:       token,
			err:       entity.ErrInvalidJTI,
			message:   "JTI claim is not a string",
			errorCode: code.InvalidJWT,
		})
	}

	// 獲取 UID (可能在 data 中)
	var uid string
	if dataInterface, exists := claimMap["data"]; exists {
		if dataMap, ok := dataInterface.(map[string]interface{}); ok {
			if uidInterface, exists := dataMap["uid"]; exists {
				uid, _ = uidInterface.(string)
			}
		}
	}

	// 獲取過期時間
	exp, exists := claimMap["exp"]
	if !exists {
		return use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "BlacklistToken.getExp",
			req:       token,
			err:       entity.ErrTokenExpired,
			message:   "token missing exp claim",
			errorCode: code.TokenExpired,
		})
	}

	// 將 exp 轉換為 int64 (JWT 中通常是 float64)
	var expInt int64
	switch v := exp.(type) {
	case float64:
		expInt = int64(v)
	case int64:
		expInt = v
	case string:
		parsedExp, err := strconv.ParseInt(v, 10, 64)
		if err != nil {
			return use.wrapTokenError(ctx, wrapTokenErrorReq{
				funcName:  "BlacklistToken.parseExp",
				req:       token,
				err:       err,
				message:   "failed to parse exp claim",
				errorCode: code.TokenExpired,
			})
		}
		expInt = parsedExp
	default:
		return use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "BlacklistToken.convertExp",
			req:       token,
			err:       fmt.Errorf("exp claim is not a valid type: %T", exp),
			message:   "exp claim type conversion failed",
			errorCode: code.TokenExpired,
		})
	}

	// 創建黑名單條目
	blacklistEntry := &entity.BlacklistEntry{
		JTI:       jtiStr,
		UID:       uid,
		ExpiresAt: expInt,
		CreatedAt: time.Now().Unix(),
	}

	// 添加到黑名單
	err = use.TokenRepo.AddToBlacklist(ctx, blacklistEntry, 0) // TTL=0 表示使用默認計算
	if err != nil {
		return use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "BlacklistToken.AddToBlacklist",
			req:       jtiStr,
			err:       err,
			message:   "failed to add token to blacklist",
			errorCode: code.TokenCreateError,
		})
	}

	logx.WithContext(ctx).Infow("token blacklisted", 
		logx.Field("jti", jtiStr),
		logx.Field("uid", uid),
		logx.Field("reason", reason))

	return nil
}

// IsTokenBlacklisted 檢查 JWT token 是否在黑名單中
func (use *TokenUseCase) IsTokenBlacklisted(ctx context.Context, jti string) (bool, error) {
	isBlacklisted, err := use.TokenRepo.IsBlacklisted(ctx, jti)
	if err != nil {
		return false, use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "IsTokenBlacklisted",
			req:       jti,
			err:       err,
			message:   "failed to check blacklist status",
			errorCode: code.TokenValidateError,
		})
	}

	return isBlacklisted, nil
}

// BlacklistAllUserTokens 將用戶的所有 token 加入黑名單 (全設備登出)
func (use *TokenUseCase) BlacklistAllUserTokens(ctx context.Context, uid string, reason string) error {
	// 獲取用戶的所有 token
	tokens, err := use.TokenRepo.GetAccessTokensByUID(ctx, uid)
	if err != nil {
		return use.wrapTokenError(ctx, wrapTokenErrorReq{
			funcName:  "BlacklistAllUserTokens.GetAccessTokensByUID",
			req:       uid,
			err:       err,
			message:   "failed to get user tokens",
			errorCode: code.TokenValidateError,
		})
	}

	// 為每個 token 創建黑名單條目
	for _, token := range tokens {
		// 解析 token 獲取 JTI 和過期時間
		claims, err := parseClaims(token.AccessToken, use.Config.Token.AccessSecret, false)
		if err != nil {
			logx.WithContext(ctx).Errorw("failed to parse token for blacklisting",
				logx.Field("uid", uid),
				logx.Field("tokenID", token.ID),
				logx.Field("error", err))
			continue // 跳過無效的 token，繼續處理其他 token
		}

		jti, exists := claims["jti"]
		if !exists || jti == "" {
			logx.WithContext(ctx).Errorw("token missing JTI claim",
				logx.Field("uid", uid),
				logx.Field("tokenID", token.ID))
			continue
		}

		exp, exists := claims["exp"]
		if !exists {
			logx.WithContext(ctx).Errorw("token missing exp claim",
				logx.Field("uid", uid),
				logx.Field("tokenID", token.ID))
			continue
		}

		// 將 exp 字符串轉換為 int64
		expInt, err := strconv.ParseInt(exp, 10, 64)
		if err != nil {
			logx.WithContext(ctx).Errorw("failed to parse exp claim",
				logx.Field("uid", uid),
				logx.Field("tokenID", token.ID),
				logx.Field("error", err))
			continue
		}

		// 創建黑名單條目
		blacklistEntry := &entity.BlacklistEntry{
			JTI:       jti,
			UID:       uid,
			ExpiresAt: expInt,
			CreatedAt: time.Now().Unix(),
		}

		// 添加到黑名單
		err = use.TokenRepo.AddToBlacklist(ctx, blacklistEntry, 0) // TTL=0 表示使用默認計算
		if err != nil {
			logx.WithContext(ctx).Errorw("failed to add token to blacklist",
				logx.Field("uid", uid),
				logx.Field("jti", jti),
				logx.Field("error", err))
			// 繼續處理其他 token，不要因為一個失敗就停止
		}
	}

	// 刪除用戶的所有 token 記錄
	err = use.TokenRepo.DeleteAccessTokensByUID(ctx, uid)
	if err != nil {
		logx.WithContext(ctx).Errorw("failed to delete user tokens",
			logx.Field("uid", uid),
			logx.Field("error", err))
		// 這不是致命錯誤，因為 token 已經被加入黑名單
	}

	logx.WithContext(ctx).Infow("all user tokens blacklisted",
		logx.Field("uid", uid),
		logx.Field("tokenCount", len(tokens)),
		logx.Field("reason", reason))

	return nil
}