package service

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

	"github.com/google/uuid"
	"go.uber.org/zap"
	"gorm.io/gorm"
)

// profileServiceImpl ProfileService的实现
type profileServiceImpl struct {
	profileRepo repository.ProfileRepository
	userRepo    repository.UserRepository
	logger      *zap.Logger
}

// NewProfileService 创建ProfileService实例
func NewProfileService(
	profileRepo repository.ProfileRepository,
	userRepo repository.UserRepository,
	logger *zap.Logger,
) ProfileService {
	return &profileServiceImpl{
		profileRepo: profileRepo,
		userRepo:    userRepo,
		logger:      logger,
	}
}

func (s *profileServiceImpl) Create(userID int64, name string) (*model.Profile, error) {
	// 验证用户存在
	user, err := s.userRepo.FindByID(userID)
	if err != nil || user == nil {
		return nil, errors.New("用户不存在")
	}
	if user.Status != 1 {
		return nil, errors.New("用户状态异常")
	}

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

	// 生成UUID和RSA密钥
	profileUUID := uuid.New().String()
	privateKey, err := generateRSAPrivateKeyInternal()
	if err != nil {
		return nil, fmt.Errorf("生成RSA密钥失败: %w", err)
	}

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

	if err := s.profileRepo.Create(profile); err != nil {
		return nil, fmt.Errorf("创建档案失败: %w", err)
	}

	// 设置活跃状态
	if err := s.profileRepo.SetActive(profileUUID, userID); err != nil {
		return nil, fmt.Errorf("设置活跃状态失败: %w", err)
	}

	return profile, nil
}

func (s *profileServiceImpl) GetByUUID(uuid string) (*model.Profile, error) {
	profile, err := s.profileRepo.FindByUUID(uuid)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, ErrProfileNotFound
		}
		return nil, fmt.Errorf("查询档案失败: %w", err)
	}
	return profile, nil
}

func (s *profileServiceImpl) GetByUserID(userID int64) ([]*model.Profile, error) {
	profiles, err := s.profileRepo.FindByUserID(userID)
	if err != nil {
		return nil, fmt.Errorf("查询档案列表失败: %w", err)
	}
	return profiles, nil
}

func (s *profileServiceImpl) Update(uuid string, userID int64, name *string, skinID, capeID *int64) (*model.Profile, error) {
	// 获取档案并验证权限
	profile, err := s.profileRepo.FindByUUID(uuid)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, ErrProfileNotFound
		}
		return nil, fmt.Errorf("查询档案失败: %w", err)
	}

	if profile.UserID != userID {
		return nil, ErrProfileNoPermission
	}

	// 检查角色名是否重复
	if name != nil && *name != profile.Name {
		existingName, err := s.profileRepo.FindByName(*name)
		if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
			return nil, fmt.Errorf("查询角色名失败: %w", err)
		}
		if existingName != nil {
			return nil, errors.New("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 := s.profileRepo.Update(profile); err != nil {
		return nil, fmt.Errorf("更新档案失败: %w", err)
	}

	return s.profileRepo.FindByUUID(uuid)
}

func (s *profileServiceImpl) Delete(uuid string, userID int64) error {
	// 获取档案并验证权限
	profile, err := s.profileRepo.FindByUUID(uuid)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return ErrProfileNotFound
		}
		return fmt.Errorf("查询档案失败: %w", err)
	}

	if profile.UserID != userID {
		return ErrProfileNoPermission
	}

	if err := s.profileRepo.Delete(uuid); err != nil {
		return fmt.Errorf("删除档案失败: %w", err)
	}
	return nil
}

func (s *profileServiceImpl) SetActive(uuid string, userID int64) error {
	// 获取档案并验证权限
	profile, err := s.profileRepo.FindByUUID(uuid)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return ErrProfileNotFound
		}
		return fmt.Errorf("查询档案失败: %w", err)
	}

	if profile.UserID != userID {
		return ErrProfileNoPermission
	}

	if err := s.profileRepo.SetActive(uuid, userID); err != nil {
		return fmt.Errorf("设置活跃状态失败: %w", err)
	}

	if err := s.profileRepo.UpdateLastUsedAt(uuid); err != nil {
		return fmt.Errorf("更新使用时间失败: %w", err)
	}

	return nil
}

func (s *profileServiceImpl) CheckLimit(userID int64, maxProfiles int) error {
	count, err := s.profileRepo.CountByUserID(userID)
	if err != nil {
		return fmt.Errorf("查询档案数量失败: %w", err)
	}

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

func (s *profileServiceImpl) GetByNames(names []string) ([]*model.Profile, error) {
	profiles, err := s.profileRepo.GetByNames(names)
	if err != nil {
		return nil, fmt.Errorf("查找失败: %w", err)
	}
	return profiles, nil
}

func (s *profileServiceImpl) GetByProfileName(name string) (*model.Profile, error) {
	profile, err := s.profileRepo.FindByName(name)
	if err != nil {
		return nil, errors.New("用户角色未创建")
	}
	return profile, nil
}

// generateRSAPrivateKeyInternal 生成RSA-2048私钥（PEM格式）
func generateRSAPrivateKeyInternal() (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
}