package service

import (
	"errors"
	"fmt"
	"time"

	"github.com/2930134478/AI-CS/backend/models"
	"github.com/2930134478/AI-CS/backend/repository"
	"github.com/2930134478/AI-CS/backend/utils"
)

// EmbeddingConfigService 知识库向量配置服务
type EmbeddingConfigService struct {
	repo     *repository.EmbeddingConfigRepository
	userRepo *repository.UserRepository
}

// NewEmbeddingConfigService 创建服务实例
func NewEmbeddingConfigService(repo *repository.EmbeddingConfigRepository, userRepo *repository.UserRepository) *EmbeddingConfigService {
	return &EmbeddingConfigService{repo: repo, userRepo: userRepo}
}

// GetForAPI 返回给前端的配置（API Key 脱敏，不返回明文）
func (s *EmbeddingConfigService) GetForAPI() (*EmbeddingConfigResult, error) {
	c, err := s.repo.Get()
	if err != nil {
		return nil, err
	}
	if c == nil {
		return &EmbeddingConfigResult{
			EmbeddingType:           "openai",
			APIURL:                  "",
			APIKeyMasked:            "",
			Model:                   "text-embedding-3-small",
			CustomerCanUseKB:        true,
			VisitorWebSearchEnabled: false,
			WebSearchSource:         "custom",
		}, nil
	}
	masked := ""
	if c.APIKey != "" {
		masked = "sk-***"
	}
	return &EmbeddingConfigResult{
		ID:                       c.ID,
		EmbeddingType:             c.EmbeddingType,
		APIURL:                    c.APIURL,
		APIKeyMasked:              masked,
		Model:                     c.Model,
		CustomerCanUseKB:          c.CustomerCanUseKB,
		VisitorWebSearchEnabled:   c.VisitorWebSearchEnabled,
		WebSearchSource:           normalizeWebSearchSource(c.WebSearchSource),
		UpdatedAt:                 c.UpdatedAt,
	}, nil
}

func normalizeWebSearchSource(v string) string {
	if v == "vendor" || v == "custom" {
		return v
	}
	return "custom"
}

// GetRaw 供 embedding 工厂使用，返回含解密后 API Key 的配置；若 DB 无有效配置返回 nil, nil
func (s *EmbeddingConfigService) GetRaw() (embeddingType, apiURL, apiKey, model string, err error) {
	c, err := s.repo.Get()
	if err != nil || c == nil || c.APIKey == "" {
		return "", "", "", "", nil
	}
	decrypted, err := utils.DecryptAPIKey(c.APIKey)
	if err != nil {
		return "", "", "", "", fmt.Errorf("解密 API Key 失败: %w", err)
	}
	return c.EmbeddingType, c.APIURL, decrypted, c.Model, nil
}

// CustomerCanUseKB 是否开放知识库给客服使用
func (s *EmbeddingConfigService) CustomerCanUseKB() (bool, error) {
	c, err := s.repo.Get()
	if err != nil {
		return false, err
	}
	if c == nil {
		return true, nil // 默认开放
	}
	return c.CustomerCanUseKB, nil
}

// GetVisitorWebSearchConfig 返回访客端联网设置（供小窗拉取，无需登录）
func (s *EmbeddingConfigService) GetVisitorWebSearchConfig() (*VisitorWebSearchConfig, error) {
	c, err := s.repo.Get()
	if err != nil {
		return nil, err
	}
	if c == nil {
		return &VisitorWebSearchConfig{WebSearchEnabled: false}, nil
	}
	return &VisitorWebSearchConfig{WebSearchEnabled: c.VisitorWebSearchEnabled}, nil
}

// GetWebSearchSource 返回联网方式：vendor（厂商内置）/ custom（自建 Serper）
func (s *EmbeddingConfigService) GetWebSearchSource() (string, error) {
	c, err := s.repo.Get()
	if err != nil {
		return "custom", err
	}
	if c == nil {
		return "custom", nil
	}
	return normalizeWebSearchSource(c.WebSearchSource), nil
}

// CheckKnowledgeBaseAccess 校验当前用户是否允许使用知识库（创建/上传/导入等）
// 若未开放且用户非 admin 则返回 error
func (s *EmbeddingConfigService) CheckKnowledgeBaseAccess(userID uint) error {
	ok, err := s.CustomerCanUseKB()
	if err != nil {
		return err
	}
	if ok {
		return nil
	}
	user, err := s.userRepo.GetByID(userID)
	if err != nil || user == nil {
		return errors.New("用户不存在")
	}
	if user.Role == "admin" {
		return nil
	}
	return errors.New("当前未开放知识库功能，仅管理员可使用")
}

// Update 更新配置（仅管理员可调）；若传入 api_key 为空则保留原密钥
func (s *EmbeddingConfigService) Update(userID uint, input UpdateEmbeddingConfigInput) (*EmbeddingConfigResult, error) {
	user, err := s.userRepo.GetByID(userID)
	if err != nil || user == nil {
		return nil, errors.New("用户不存在")
	}
	if user.Role != "admin" {
		return nil, errors.New("仅管理员可修改知识库向量配置")
	}

	c, err := s.repo.Get()
	if err != nil {
		return nil, err
	}
	if c == nil {
		c = &models.EmbeddingConfig{ID: 1}
	}

	if input.EmbeddingType != nil {
		c.EmbeddingType = *input.EmbeddingType
	}
	if input.APIURL != nil {
		c.APIURL = *input.APIURL
	}
	if input.APIKey != nil && *input.APIKey != "" {
		encrypted, err := utils.EncryptAPIKey(*input.APIKey)
		if err != nil {
			return nil, fmt.Errorf("加密 API Key 失败: %v", err)
		}
		c.APIKey = encrypted
	}
	if input.Model != nil {
		c.Model = *input.Model
	}
	if input.CustomerCanUseKB != nil {
		c.CustomerCanUseKB = *input.CustomerCanUseKB
	}
	if input.VisitorWebSearchEnabled != nil {
		c.VisitorWebSearchEnabled = *input.VisitorWebSearchEnabled
	}
	if input.WebSearchSource != nil {
		c.WebSearchSource = normalizeWebSearchSource(*input.WebSearchSource)
	}

	if err := s.repo.Save(c); err != nil {
		return nil, err
	}
	return s.GetForAPI()
}

// EmbeddingConfigResult 返回给前端的结构（不含明文 API Key）
type EmbeddingConfigResult struct {
	ID                      uint      `json:"id"`
	EmbeddingType           string    `json:"embedding_type"`
	APIURL                  string    `json:"api_url"`
	APIKeyMasked            string    `json:"api_key_masked"`
	Model                   string    `json:"model"`
	CustomerCanUseKB        bool      `json:"customer_can_use_kb"`
	VisitorWebSearchEnabled bool      `json:"visitor_web_search_enabled"`
	WebSearchSource         string    `json:"web_search_source"`
	UpdatedAt               time.Time `json:"updated_at,omitempty"`
}

// VisitorWebSearchConfig 访客端联网设置（供小窗拉取，无需登录）
type VisitorWebSearchConfig struct {
	WebSearchEnabled bool `json:"web_search_enabled"`
}

// UpdateEmbeddingConfigInput 更新入参
type UpdateEmbeddingConfigInput struct {
	EmbeddingType           *string `json:"embedding_type"`
	APIURL                  *string `json:"api_url"`
	APIKey                  *string `json:"api_key"`
	Model                   *string `json:"model"`
	CustomerCanUseKB        *bool   `json:"customer_can_use_kb"`
	VisitorWebSearchEnabled *bool   `json:"visitor_web_search_enabled"`
	WebSearchSource         *string `json:"web_search_source"`
}