package service

import (
	"carrotskin/internal/model"
	"carrotskin/internal/repository"
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"encoding/pem"
	"errors"
	"fmt"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
	"gorm.io/gorm"
)

// CreateProfile 创建档案
func CreateProfile(db *gorm.DB, userID int64, name string) (*model.Profile, error) {
	// 验证用户存在
	user, err := EnsureUserExists(userID)
	if err != nil {
		return nil, err
	}
	if user.Status != 1 {
		return nil, fmt.Errorf("用户状态异常")
	}

	// 检查角色名是否已存在
	existingName, err := repository.FindProfileByName(name)
	if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
		return nil, WrapError(err, "查询角色名失败")
	}
	if existingName != nil {
		return nil, fmt.Errorf("角色名已被使用")
	}

	// 生成UUID和RSA密钥
	profileUUID := uuid.New().String()
	privateKey, err := generateRSAPrivateKey()
	if err != nil {
		return nil, WrapError(err, "生成RSA密钥失败")
	}

	// 创建档案
	profile := &model.Profile{
		UUID:          profileUUID,
		UserID:        userID,
		Name:          name,
		RSAPrivateKey: privateKey,
		IsActive:      true,
	}

	if err := repository.CreateProfile(profile); err != nil {
		return nil, WrapError(err, "创建档案失败")
	}

	// 设置活跃状态
	if err := repository.SetActiveProfile(profileUUID, userID); err != nil {
		return nil, WrapError(err, "设置活跃状态失败")
	}

	return profile, nil
}

// GetProfileByUUID 获取档案详情
func GetProfileByUUID(db *gorm.DB, uuid string) (*model.Profile, error) {
	profile, err := repository.FindProfileByUUID(uuid)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, ErrProfileNotFound
		}
		return nil, WrapError(err, "查询档案失败")
	}
	return profile, nil
}

// GetUserProfiles 获取用户的所有档案
func GetUserProfiles(db *gorm.DB, userID int64) ([]*model.Profile, error) {
	profiles, err := repository.FindProfilesByUserID(userID)
	if err != nil {
		return nil, WrapError(err, "查询档案列表失败")
	}
	return profiles, nil
}

// UpdateProfile 更新档案
func UpdateProfile(db *gorm.DB, uuid string, userID int64, name *string, skinID, capeID *int64) (*model.Profile, error) {
	// 获取档案并验证权限
	profile, err := GetProfileWithPermissionCheck(uuid, userID)
	if err != nil {
		return nil, err
	}

	// 检查角色名是否重复
	if name != nil && *name != profile.Name {
		existingName, err := repository.FindProfileByName(*name)
		if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, WrapError(err, "查询角色名失败")
		}
		if existingName != nil {
			return nil, fmt.Errorf("角色名已被使用")
		}
		profile.Name = *name
	}

	// 更新皮肤和披风
	if skinID != nil {
		profile.SkinID = skinID
	}
	if capeID != nil {
		profile.CapeID = capeID
	}

	if err := repository.UpdateProfile(profile); err != nil {
		return nil, WrapError(err, "更新档案失败")
	}

	return repository.FindProfileByUUID(uuid)
}

// DeleteProfile 删除档案
func DeleteProfile(db *gorm.DB, uuid string, userID int64) error {
	if _, err := GetProfileWithPermissionCheck(uuid, userID); err != nil {
		return err
	}

	if err := repository.DeleteProfile(uuid); err != nil {
		return WrapError(err, "删除档案失败")
	}
	return nil
}

// SetActiveProfile 设置活跃档案
func SetActiveProfile(db *gorm.DB, uuid string, userID int64) error {
	if _, err := GetProfileWithPermissionCheck(uuid, userID); err != nil {
		return err
	}

	if err := repository.SetActiveProfile(uuid, userID); err != nil {
		return WrapError(err, "设置活跃状态失败")
	}

	if err := repository.UpdateProfileLastUsedAt(uuid); err != nil {
		return WrapError(err, "更新使用时间失败")
	}

	return nil
}

// CheckProfileLimit 检查用户档案数量限制
func CheckProfileLimit(db *gorm.DB, userID int64, maxProfiles int) error {
	count, err := repository.CountProfilesByUserID(userID)
	if err != nil {
		return WrapError(err, "查询档案数量失败")
	}

	if int(count) >= maxProfiles {
		return fmt.Errorf("已达到档案数量上限（%d个）", maxProfiles)
	}
	return nil
}

// generateRSAPrivateKey 生成RSA-2048私钥（PEM格式）
func generateRSAPrivateKey() (string, error) {
	privateKey, err := rsa.GenerateKey(rand.Reader, 2048)
	if err != nil {
		return "", err
	}

	privateKeyBytes := x509.MarshalPKCS1PrivateKey(privateKey)
	privateKeyPEM := pem.EncodeToMemory(&pem.Block{
		Type:  "RSA PRIVATE KEY",
		Bytes: privateKeyBytes,
	})

	return string(privateKeyPEM), nil
}

func ValidateProfileByUserID(db *gorm.DB, userId int64, UUID string) (bool, error) {
	if userId == 0 || UUID == "" {
		return false, errors.New("用户ID或配置文件ID不能为空")
	}

	profile, err := repository.FindProfileByUUID(UUID)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return false, errors.New("配置文件不存在")
		}
		return false, WrapError(err, "验证配置文件失败")
	}
	return profile.UserID == userId, nil
}

func GetProfilesDataByNames(db *gorm.DB, names []string) ([]*model.Profile, error) {
	profiles, err := repository.GetProfilesByNames(names)
	if err != nil {
		return nil, WrapError(err, "查找失败")
	}
	return profiles, nil
}

func GetProfileKeyPair(db *gorm.DB, profileId string) (*model.KeyPair, error) {
	keyPair, err := repository.GetProfileKeyPair(profileId)
	if err != nil {
		return nil, WrapError(err, "查找失败")
	}
	return keyPair, nil
}