package service

import (
	"errors"
	"fmt"
	"time"

	"gorm.io/gorm"

	"gitea.kmux.cn/zhilv/scriptforge/internal/idgen"
	"gitea.kmux.cn/zhilv/scriptforge/internal/model"
)

var (
	ErrNotFound         = errors.New("script not found or expired")
	ErrAlreadyPublished = errors.New("script already published")
	ErrInvalidCategory  = errors.New("invalid category")
)

type ScriptService struct {
	db *gorm.DB
}

func NewScriptService(db *gorm.DB) *ScriptService {
	return &ScriptService{db: db}
}

type CreateInput struct {
	Title       string
	Description string
	Content     string
	CategoryID  uint
	ExpiresIn   string
	Publish     bool
	UserID      uint
}

type CreateResult struct {
	Script     model.Script
	AdminToken string
	RawURL     string
}

func (s *ScriptService) Create(input CreateInput, scheme, host string) (*CreateResult, error) {
	var cat model.RuntimeCategory
	if err := s.db.First(&cat, input.CategoryID).Error; err != nil {
		return nil, ErrInvalidCategory
	}

	var d time.Duration
	switch input.ExpiresIn {
	case "1h":
		d = 1 * time.Hour
	case "24h":
		d = 24 * time.Hour
	case "7d":
		d = 7 * 24 * time.Hour
	case "30d":
		d = 30 * 24 * time.Hour
	default:
		d = 24 * time.Hour
	}

	id, err := idgen.GenerateID(8)
	if err != nil {
		return nil, err
	}

	adminToken, err := idgen.GenerateToken()
	if err != nil {
		return nil, err
	}

	status := "draft"
	var publishedAt *time.Time
	if input.Publish {
		status = "published"
		now := time.Now()
		publishedAt = &now
	}

	script := model.Script{
		ID:          id,
		Title:       input.Title,
		Description: input.Description,
		Content:     input.Content,
		CategoryID:  input.CategoryID,
		UserID:      input.UserID,
		AdminToken:  adminToken,
		Status:      status,
		ExpiresAt:   time.Now().Add(d),
		PublishedAt: publishedAt,
	}

	if err := s.db.Create(&script).Error; err != nil {
		return nil, err
	}

	rawURL := scheme + "://" + host + "/raw/" + id

	return &CreateResult{
		Script:     script,
		AdminToken: adminToken,
		RawURL:     rawURL,
	}, nil
}

func (s *ScriptService) GetByID(id string) (*model.Script, error) {
	var script model.Script
	err := s.db.Where("id = ? AND expires_at > ?", id, time.Now()).First(&script).Error
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return nil, ErrNotFound
	}
	return &script, err
}

func (s *ScriptService) GetCategoryByID(id uint) (*model.RuntimeCategory, error) {
	var cat model.RuntimeCategory
	err := s.db.Preload("Variants").First(&cat, id).Error
	return &cat, err
}

func (s *ScriptService) GetVariants(categoryID uint) ([]model.RuntimeVariant, error) {
	var variants []model.RuntimeVariant
	err := s.db.Where("category_id = ?", categoryID).Order("sort_order ASC").Find(&variants).Error
	return variants, err
}

func (s *ScriptService) GetDefaultVariant(categoryID uint) (*model.RuntimeVariant, error) {
	var v model.RuntimeVariant
	err := s.db.Where("category_id = ? AND is_default = true", categoryID).First(&v).Error
	if errors.Is(err, gorm.ErrRecordNotFound) {
		err = s.db.Where("category_id = ?", categoryID).Order("sort_order ASC").First(&v).Error
	}
	return &v, err
}

func (s *ScriptService) Publish(id, token string) (*model.Script, error) {
	var script model.Script
	err := s.db.Where("id = ? AND admin_token = ? AND expires_at > ?", id, token, time.Now()).First(&script).Error
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return nil, ErrNotFound
	}
	if err != nil {
		return nil, err
	}
	if script.Status == "published" {
		return nil, ErrAlreadyPublished
	}

	now := time.Now()
	script.Status = "published"
	script.PublishedAt = &now
	if err := s.db.Save(&script).Error; err != nil {
		return nil, err
	}
	return &script, nil
}

type MarketQuery struct {
	Page       int
	PerPage    int
	CategoryID uint
	Search     string
}

type MarketResult struct {
	Items   []model.Script
	Total   int64
	Page    int
	PerPage int
}

func (s *ScriptService) ListMarket(q MarketQuery) (*MarketResult, error) {
	if q.Page < 1 {
		q.Page = 1
	}
	if q.PerPage < 1 || q.PerPage > 50 {
		q.PerPage = 20
	}

	query := s.db.Model(&model.Script{}).
		Where("status = ? AND expires_at > ?", "published", time.Now())

	if q.CategoryID > 0 {
		query = query.Where("category_id = ?", q.CategoryID)
	}
	if q.Search != "" {
		search := "%" + q.Search + "%"
		query = query.Where("title LIKE ? OR description LIKE ?", search, search)
	}

	var total int64
	query.Count(&total)

	var scripts []model.Script
	err := query.Order("published_at DESC").
		Offset((q.Page - 1) * q.PerPage).
		Limit(q.PerPage).
		Find(&scripts).Error

	return &MarketResult{
		Items:   scripts,
		Total:   total,
		Page:    q.Page,
		PerPage: q.PerPage,
	}, err
}

func (s *ScriptService) Delete(id, token string) error {
	result := s.db.Where("id = ? AND admin_token = ?", id, token).Delete(&model.Script{})
	if result.RowsAffected == 0 {
		return ErrNotFound
	}
	return result.Error
}

func (s *ScriptService) CleanupExpired() (int64, error) {
	result := s.db.Where("expires_at <= ?", time.Now()).Delete(&model.Script{})
	return result.RowsAffected, result.Error
}

func (s *ScriptService) ListCategories() ([]model.RuntimeCategory, error) {
	var cats []model.RuntimeCategory
	err := s.db.Preload("Variants").Order("sort_order ASC").Find(&cats).Error
	return cats, err
}

func (s *ScriptService) CreateCategory(cat *model.RuntimeCategory) error {
	return s.db.Create(cat).Error
}

func (s *ScriptService) UpdateCategory(cat *model.RuntimeCategory) error {
	return s.db.Save(cat).Error
}

func (s *ScriptService) DeleteCategory(id uint) error {
	s.db.Where("category_id = ?", id).Delete(&model.RuntimeVariant{})
	return s.db.Delete(&model.RuntimeCategory{}, id).Error
}

func (s *ScriptService) CreateVariant(v *model.RuntimeVariant) error {
	return s.db.Create(v).Error
}

func (s *ScriptService) UpdateVariant(v *model.RuntimeVariant) error {
	return s.db.Save(v).Error
}

func (s *ScriptService) DeleteVariant(id uint) error {
	return s.db.Delete(&model.RuntimeVariant{}, id).Error
}

func FormatCommand(template, url string) string {
	return fmt.Sprintf(template, url)
}