import db from "../index.js"

class ArticleModel {
    static async findAll() {
        return db("articles").orderBy("created_at", "desc")
    }

    static async findPublished() {
        return db("articles")
            .where("status", "published")
            .whereNotNull("published_at")
            .orderBy("published_at", "desc")
    }

    static async findDrafts() {
        return db("articles")
            .where("status", "draft")
            .orderBy("updated_at", "desc")
    }

    static async findById(id) {
        return db("articles").where("id", id).first()
    }

    static async findBySlug(slug) {
        return db("articles").where("slug", slug).first()
    }

    static async findByAuthor(author) {
        return db("articles")
            .where("author", author)
            .where("status", "published")
            .orderBy("published_at", "desc")
    }

    static async findByCategory(category) {
        return db("articles")
            .where("category", category)
            .where("status", "published")
            .orderBy("published_at", "desc")
    }

    static async findByTags(tags) {
        // 支持多个标签搜索，标签以逗号分隔
        const tagArray = tags.split(',').map(tag => tag.trim())
        return db("articles")
            .where("status", "published")
            .whereRaw("tags LIKE ?", [`%${tagArray[0]}%`])
            .orderBy("published_at", "desc")
    }

    static async searchByKeyword(keyword) {
        return db("articles")
            .where("status", "published")
            .where(function() {
                this.where("title", "like", `%${keyword}%`)
                    .orWhere("content", "like", `%${keyword}%`)
                    .orWhere("keywords", "like", `%${keyword}%`)
                    .orWhere("description", "like", `%${keyword}%`)
                    .orWhere("excerpt", "like", `%${keyword}%`)
            })
            .orderBy("published_at", "desc")
    }

    static async create(data) {
        // 验证必填字段
        if (!data.title || !data.content) {
            throw new Error("标题和内容为必填字段")
        }

        // 处理标签，确保格式一致
        let tags = data.tags
        if (tags && typeof tags === "string") {
            tags = tags.split(',').map(tag => tag.trim()).filter(tag => tag).join(', ')
        }

        // 生成slug（如果未提供）
        let slug = data.slug
        if (!slug) {
            slug = this.generateSlug(data.title)
        }

        // 计算阅读时间（如果未提供）
        let readingTime = data.reading_time
        if (!readingTime) {
            readingTime = this.calculateReadingTime(data.content)
        }

        // 生成摘要（如果未提供）
        let excerpt = data.excerpt
        if (!excerpt && data.content) {
            excerpt = this.generateExcerpt(data.content)
        }

        return db("articles").insert({
            ...data,
            tags,
            slug,
            reading_time: readingTime,
            excerpt,
            status: data.status || "draft",
            view_count: 0,
            created_at: db.fn.now(),
            updated_at: db.fn.now(),
        }).returning("*")
    }

    static async update(id, data) {
        const current = await db("articles").where("id", id).first()
        if (!current) {
            throw new Error("文章不存在")
        }

        // 处理标签，确保格式一致
        let tags = data.tags
        if (tags && typeof tags === "string") {
            tags = tags.split(',').map(tag => tag.trim()).filter(tag => tag).join(', ')
        }

        // 生成slug（如果标题改变且未提供slug）
        let slug = data.slug
        if (data.title && data.title !== current.title && !slug) {
            slug = this.generateSlug(data.title)
        }

        // 计算阅读时间（如果内容改变且未提供）
        let readingTime = data.reading_time
        if (data.content && data.content !== current.content && !readingTime) {
            readingTime = this.calculateReadingTime(data.content)
        }

        // 生成摘要（如果内容改变且未提供）
        let excerpt = data.excerpt
        if (data.content && data.content !== current.content && !excerpt) {
            excerpt = this.generateExcerpt(data.content)
        }

        // 如果状态改为published，设置发布时间
        let publishedAt = data.published_at
        if (data.status === "published" && current.status !== "published" && !publishedAt) {
            publishedAt = db.fn.now()
        }

        return db("articles").where("id", id).update({
            ...data,
            tags: tags || current.tags,
            slug: slug || current.slug,
            reading_time: readingTime || current.reading_time,
            excerpt: excerpt || current.excerpt,
            published_at: publishedAt || current.published_at,
            updated_at: db.fn.now(),
        }).returning("*")
    }

    static async delete(id) {
        const article = await db("articles").where("id", id).first()
        if (!article) {
            throw new Error("文章不存在")
        }
        return db("articles").where("id", id).del()
    }

    static async publish(id) {
        return db("articles")
            .where("id", id)
            .update({
                status: "published",
                published_at: db.fn.now(),
                updated_at: db.fn.now(),
            })
            .returning("*")
    }

    static async unpublish(id) {
        return db("articles")
            .where("id", id)
            .update({
                status: "draft",
                published_at: null,
                updated_at: db.fn.now(),
            })
            .returning("*")
    }

    static async incrementViewCount(id) {
        return db("articles")
            .where("id", id)
            .increment("view_count", 1)
            .returning("*")
    }

    static async findByDateRange(startDate, endDate) {
        return db("articles")
            .where("status", "published")
            .whereBetween("published_at", [startDate, endDate])
            .orderBy("published_at", "desc")
    }

    static async getArticleCount() {
        const result = await db("articles").count("id as count").first()
        return result ? result.count : 0
    }

    static async getPublishedArticleCount() {
        const result = await db("articles")
            .where("status", "published")
            .count("id as count")
            .first()
        return result ? result.count : 0
    }

    static async getArticleCountByCategory() {
        return db("articles")
            .select("category")
            .count("id as count")
            .where("status", "published")
            .groupBy("category")
            .orderBy("count", "desc")
    }

    static async getArticleCountByStatus() {
        return db("articles")
            .select("status")
            .count("id as count")
            .groupBy("status")
            .orderBy("count", "desc")
    }

    static async getRecentArticles(limit = 10) {
        return db("articles")
            .where("status", "published")
            .orderBy("published_at", "desc")
            .limit(limit)
    }

    static async getPopularArticles(limit = 10) {
        return db("articles")
            .where("status", "published")
            .orderBy("view_count", "desc")
            .limit(limit)
    }

    static async getFeaturedArticles(limit = 5) {
        return db("articles")
            .where("status", "published")
            .whereNotNull("featured_image")
            .orderBy("published_at", "desc")
            .limit(limit)
    }

    static async getRelatedArticles(articleId, limit = 5) {
        const current = await this.findById(articleId)
        if (!current) return []

        return db("articles")
            .where("status", "published")
            .where("id", "!=", articleId)
            .where(function() {
                if (current.category) {
                    this.orWhere("category", current.category)
                }
                if (current.tags) {
                    const tags = current.tags.split(',').map(tag => tag.trim())
                    tags.forEach(tag => {
                        this.orWhereRaw("tags LIKE ?", [`%${tag}%`])
                    })
                }
            })
            .orderBy("published_at", "desc")
            .limit(limit)
    }

    // 工具方法
    static generateSlug(title) {
        return title
            .toLowerCase()
            .replace(/[^\w\s-]/g, '')
            .replace(/\s+/g, '-')
            .replace(/-+/g, '-')
            .trim()
    }

    static calculateReadingTime(content) {
        // 假设平均阅读速度为每分钟200个单词
        const wordCount = content.split(/\s+/).length
        return Math.ceil(wordCount / 200)
    }

    static generateExcerpt(content, maxLength = 150) {
        if (content.length <= maxLength) {
            return content
        }
        return content.substring(0, maxLength).trim() + "..."
    }
}

export default ArticleModel
export { ArticleModel }