package models

import (
	"encoding/json"
	"time"

	"gorm.io/gorm"
)

// Post 博客文章模型
type Post struct {
	ID          uint      `json:"id" gorm:"primaryKey;column:id"`
	OriginalID  string    `json:"originalId,omitempty" gorm:"-"` // For backward compatibility
	Title       string    `json:"title" gorm:"column:title"`
	CategoryID  uint      `json:"categoryId" gorm:"column:category_id"`
	Category    *Category `json:"category,omitempty" gorm:"foreignKey:CategoryID"`         // For join query result
	ColumnID    *uint     `json:"columnId,omitempty" gorm:"column:column_id;default:NULL"` // Optional column association
	Column      *Column   `json:"column,omitempty" gorm:"foreignKey:ColumnID"`             // For join query result
	Excerpt     string    `json:"excerpt" gorm:"column:excerpt"`
	Content     string    `json:"content" gorm:"column:content;type:text"`
	ReadCount   uint      `json:"readCount" gorm:"column:read_count;default:0"`
	IsPublished int       `json:"isPublished" gorm:"column:is_published;default:0"` // 0: draft, 1: published
	Tags        []Tag     `json:"tags" gorm:"many2many:post_tags;joinForeignKey:post_id;joinReferences:tag_id"`
	CreatedAt   int64     `json:"createdAt" gorm:"column:created_at"`
	UpdatedAt   int64     `json:"updatedAt" gorm:"column:updated_at"`
	DeletedAt   int64     `json:"deletedAt" gorm:"column:deleted_at;default:0"`
}

// TableName 指定表名
func (Post) TableName() string {
	return "posts"
}

// BeforeCreate 创建前钩子
func (p *Post) BeforeCreate(tx *gorm.DB) error {
	now := time.Now().Unix()
	if p.CreatedAt == 0 {
		p.CreatedAt = now
	}
	if p.UpdatedAt == 0 {
		p.UpdatedAt = now
	}
	if p.DeletedAt == 0 {
		p.DeletedAt = 0
	}
	return nil
}

// BeforeUpdate 更新前钩子
func (p *Post) BeforeUpdate(tx *gorm.DB) error {
	p.UpdatedAt = time.Now().Unix()
	return nil
}

// PostResponse 博客文章响应模型
type PostResponse struct {
	ID           uint    `json:"id"`
	Title        string  `json:"title"`
	CategoryID   uint    `json:"categoryId"`
	CategoryName string  `json:"categoryName"`
	CategorySlug string  `json:"categorySlug"`
	ColumnID     *uint   `json:"columnId,omitempty"`
	ColumnName   string  `json:"columnName,omitempty"`
	ColumnSlug   string  `json:"columnSlug,omitempty"`
	Date         string  `json:"date"`
	Excerpt      string  `json:"excerpt,omitempty"`
	Content      *string `json:"content,omitempty"` // 使用指针类型，当 includeContent=true 时总是设置
	Tags         []Tag   `json:"tags,omitempty"`
	IsPublished  int     `json:"isPublished,omitempty"`
	ReadCount    uint    `json:"readCount,omitempty"`
}

// PostHistory 文章历史记录模型
type PostHistory struct {
	ID          uint   `json:"id" gorm:"primaryKey;column:id"`
	PostID      uint   `json:"postId" gorm:"column:post_id;index"`
	Version     int    `json:"version" gorm:"column:version"`
	Title       string `json:"title" gorm:"column:title"`
	CategoryID  uint   `json:"categoryId" gorm:"column:category_id"`
	ColumnID    *uint  `json:"columnId,omitempty" gorm:"column:column_id"`
	TagIDs      string `json:"tagIds,omitempty" gorm:"column:tag_ids;type:json"`
	Excerpt     string `json:"excerpt" gorm:"column:excerpt"`
	Content     string `json:"content" gorm:"column:content;type:text"`
	IsPublished int    `json:"isPublished" gorm:"column:is_published"`
	ModifiedBy  uint   `json:"modifiedBy" gorm:"column:modified_by"`
	ModifiedAt  int64  `json:"modifiedAt" gorm:"column:modified_at"`
	CreatedAt   int64  `json:"createdAt" gorm:"column:created_at"`
}

// GetTagIDList parses stored tag_ids JSON into a slice of uint IDs.
func (ph *PostHistory) GetTagIDList() []uint {
	if ph.TagIDs == "" {
		return nil
	}
	var ids []uint
	if err := json.Unmarshal([]byte(ph.TagIDs), &ids); err != nil {
		return nil
	}
	return ids
}

// TableName 指定表名
func (PostHistory) TableName() string {
	return "post_history"
}

// BeforeCreate 创建前钩子
func (ph *PostHistory) BeforeCreate(tx *gorm.DB) error {
	now := time.Now().Unix()
	if ph.CreatedAt == 0 {
		ph.CreatedAt = now
	}
	if ph.ModifiedAt == 0 {
		ph.ModifiedAt = now
	}
	return nil
}

// PostHistoryResponse 文章历史记录响应模型
type PostHistoryResponse struct {
	ID           uint   `json:"id"`
	PostID       uint   `json:"postId"`
	Version      int    `json:"version"`
	Title        string `json:"title"`
	CategoryID   uint   `json:"categoryId"`
	CategoryName string `json:"categoryName,omitempty"`
	ColumnID     *uint  `json:"columnId,omitempty"`
	TagIDs       []uint `json:"tagIds,omitempty"`
	Excerpt      string `json:"excerpt,omitempty"`
	Content      string `json:"content,omitempty"`
	Date         string `json:"date"`
	IsPublished  int    `json:"isPublished"`
	ModifiedBy   uint   `json:"modifiedBy"`
	ModifiedAt   string `json:"modifiedAt"`
	CreatedAt    string `json:"createdAt"`
}

// PostHistoryFieldDiff 字段对比结果
type PostHistoryFieldDiff struct {
	From    string `json:"from"`
	To      string `json:"to"`
	Changed bool   `json:"changed"`
	Diff    string `json:"diff,omitempty"`
}

// PostHistoryDiffResponse 版本对比响应
type PostHistoryDiffResponse struct {
	FromVersion int                             `json:"fromVersion"`
	ToVersion   int                             `json:"toVersion"`
	Fields      map[string]PostHistoryFieldDiff `json:"fields"`
}