package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"os"
	"sort"
	"strings"
	"time"

	toc "github.com/abhinav/goldmark-toc"
	"github.com/spf13/cobra"
	meta "github.com/yuin/goldmark-meta"
	"github.com/yuin/goldmark/parser"
	"github.com/yuin/goldmark/text"
)

func generateCmd() *cobra.Command {
	var outter Outter

	cmd := &cobra.Command{
		Use:     "generate",
		Aliases: []string{"g"},
		Short:   "generate project to dist folder",
		Run: func(cmd *cobra.Command, args []string) {
			startAt := time.Now()
			// 读取配置文件
			outter.Config = readConfigFile()
			// 读取资源文件
			outter.MetaData = readDataSource()
			// 读取文章列表
			outter.Posts = readAllPosts()
			// 读取页面列表
			outter.Pages = readAllPages()
			// 读取主题模板文件
			outter.Theme = readTheme(outter.Config.Theme)
			// 数据写入模板文件
			outter.generate()
			endAt := time.Since(startAt)
			fmt.Printf("generate used: %s\n", endAt.String())
		},
	}
	return cmd
}

// readDataSource 读取资源文件
func readDataSource() map[string]interface{} {
	var source = make(map[string]interface{})
	const dataDir = "./data"
	dirs, err := os.ReadDir(dataDir)
	if err != nil {
		return nil
	}
	for _, dir := range dirs {
		if dir.IsDir() {
			continue
		}
		// 不是json文件
		if !strings.HasSuffix(dir.Name(), ".json") {
			continue
		}
		body := readFile(fmt.Sprintf("%s/%s", dataDir, dir.Name()))
		var obj interface{}
		if err := json.Unmarshal(body, &obj); err != nil {
			sfault("unmarshal file failed: %v", err)
		}
		source[strings.ReplaceAll(dir.Name(), ".json", "")] = obj
	}
	return source
}

// readPosts 读取文章
func readAllPosts() []Post {
	const postDir = "./posts"
	dirs, err := os.ReadDir(postDir)
	if err != nil {
		sfault("read directory failed: %v", err)
	}
	var posts []Post
	for _, info := range dirs {
		// 获取文件信息
		fsInfo, err := info.Info()
		if err != nil {
			sfault("read file info failed: %v", err)
		}
		// 不是目录 没有分类
		if !info.IsDir() {
			if !strings.HasSuffix(info.Name(), ".md") {
				continue
			}
			post := readPost(fmt.Sprintf("%s/%s", postDir, info.Name()))
			post.UpdatedAt = fsInfo.ModTime()
			post.UpdatedAtFormat = post.UpdatedAt.Format("2006-01-02")
			post.FileBasename = strings.ReplaceAll(fsInfo.Name(), ".md", "")
			post.Link = fmt.Sprintf("/default/%s.html", post.FileBasename)
			post.Category = "default"
			posts = append(posts, post)
			continue
		}
		// 是目录
		posts = append(posts, readPosts(postDir, info.Name())...)
	}
	sort.Slice(posts, func(i, j int) bool {
		return posts[i].CreatedAt.Unix() > posts[j].CreatedAt.Unix()
	})

	return posts
}

func readPost(fp string) Post {
	var post = Post{}
	content := readFile(fp)
	var buf bytes.Buffer

	var parserContext = parser.NewContext()
	doc := markdown.Parser().Parse(text.NewReader(content), parser.WithContext(parserContext))

	tocTree, err := toc.Inspect(doc, content)
	if err != nil {
		sfault("read content toc tree failed: %v", err)
	}

	list := toc.RenderList(tocTree)

	if list != nil {
		if err := markdown.Renderer().Render(&buf, content, list); err != nil {
			sfault("render toc content failed: %v", err)
		}
		post.TOC = buf.String()
		buf.Reset()
	}

	if err := markdown.Renderer().Render(&buf, content, doc); err != nil {
		sfault("render content failed: %v", err)
	}

	metaData := meta.Get(parserContext)
	post.CreatedAt, err = datetimeStringToTime(mustString(metaData["date"]))
	if err != nil {
		serr("get post %s created_at time failed, please check file content", post.FileBasename)
	}
	post.CreatedAtFormat = post.CreatedAt.Format("2006-01-02")
	post.Title = mustString(metaData["title"])
	post.Tags = mustStringSlice(metaData["tags"])
	post.Category = mustString(metaData["category"])
	post.MD = buf.String()
	return post
}

func readPage(fp string) Page {
	var page Page
	content := readFile(fp)
	var buf bytes.Buffer
	context := parser.NewContext()
	if err := markdown.Convert(content, &buf, parser.WithContext(context)); err != nil {
		sfault("render content failed: %v", err)
	}
	metaData := meta.Get(context)
	page.Title = mustString(metaData["title"])
	page.MD = buf.String()
	return page
}

func readPosts(base, category string) []Post {
	var dir = fmt.Sprintf("%s/%s", base, category)
	dirs, err := os.ReadDir(dir)
	if err != nil {
		sfault("read directory failed: %v", err)
	}
	var posts []Post
	for _, info := range dirs {
		if info.IsDir() {
			continue
		}
		if !strings.HasSuffix(info.Name(), ".md") {
			continue
		}
		// 获取文件信息
		fsInfo, err := info.Info()
		if err != nil {
			sfault("read file info failed: %v", err)
		}
		post := readPost(fmt.Sprintf("%s/%s", dir, info.Name()))
		post.UpdatedAt = fsInfo.ModTime()
		post.UpdatedAtFormat = post.UpdatedAt.Format("2006-01-02")
		post.FileBasename = strings.ReplaceAll(fsInfo.Name(), ".md", "")
		post.Link = fmt.Sprintf("/%s/%s.html", strings.ToLower(category), post.FileBasename)
		post.Category = category
		posts = append(posts, post)
	}
	return posts
}

func readAllPages() []Page {
	var dir = "./pages"
	dirs, err := os.ReadDir(dir)
	if err != nil {
		sfault("read directory failed: %v", err)
	}

	var pages []Page
	for _, info := range dirs {
		if info.IsDir() {
			continue
		}
		if !strings.HasSuffix(info.Name(), ".md") {
			continue
		}
		page := readPage(fmt.Sprintf("%s/%s", dir, info.Name()))
		page.Link = strings.ReplaceAll(info.Name(), ".md", "")
		pages = append(pages, page)
	}
	return pages
}

func readTheme(themeName string) Theme {
	var theme Theme
	var dir = fmt.Sprintf("./themes/%s", themeName)
	theme.BaseLayout = readFile(fmt.Sprintf("%s/base.html", dir))
	theme.IndexLayout = readFile(fmt.Sprintf("%s/index.html", dir))
	theme.PageLayout = readFile(fmt.Sprintf("%s/page.html", dir))
	theme.PostLayout = readFile(fmt.Sprintf("%s/post.html", dir))
	theme.ArchiveLayout = readFile(fmt.Sprintf("%s/archive.html", dir))
	theme.TagLayout = readFile(fmt.Sprintf("%s/tag.html", dir))

	theme.IndexLayout = bytes.ReplaceAll(theme.BaseLayout, []byte("{{layout_placeholder}}"), theme.IndexLayout)
	theme.PageLayout = bytes.ReplaceAll(theme.BaseLayout, []byte("{{layout_placeholder}}"), theme.PageLayout)
	theme.PostLayout = bytes.ReplaceAll(theme.BaseLayout, []byte("{{layout_placeholder}}"), theme.PostLayout)
	theme.ArchiveLayout = bytes.ReplaceAll(theme.BaseLayout, []byte("{{layout_placeholder}}"), theme.ArchiveLayout)
	theme.TagLayout = bytes.ReplaceAll(theme.BaseLayout, []byte("{{layout_placeholder}}"), theme.TagLayout)
	return theme
}