package site

import (
	"bufio"
	"bytes"
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
	"sort"
	"strings"
	"text/template"

	goutil "git.gutmet.org/goutil.git/misc"
	. "git.gutmet.org/wombat.git/templatestructures"
)

type metadata struct {
	explicit explicitMetadata
	subpages []string
}

type explicitMetadata struct {
	title       string
	description string
}

func (m *metadata) getSubpages() []Subpage {
	if len(m.subpages) == 0 {
		return nil
	}
	ret := make([]Subpage, 0)
	for _, path := range m.subpages {
		emd := getExplicitMetadata(path)
		if len(emd.title) > 0 && len(emd.description) > 0 {
			subpage := Subpage{emd.title, emd.description, path}
			ret = append(ret, subpage)
		}
	}
	sort.Slice(ret, func(i, j int) bool { return strings.ToUpper(ret[i].Title) < strings.ToUpper(ret[j].Title) })
	return ret
}

func metapath(htmlfile string) string {
	if !strings.HasPrefix(htmlfile, "stage1") {
		htmlfile = filepath.Join("stage1", htmlfile)
	}
	return goutil.TrimExt(htmlfile) + ".desc"
}

func getExplicitMetadata(htmlfile string) explicitMetadata {
	metapath := metapath(htmlfile)
	ret := explicitMetadata{}
	f, err := os.Open(metapath)
	if err == nil {
		defer f.Close()
		scanner := bufio.NewScanner(f)
		for scanner.Scan() {
			text := scanner.Text()
			if strings.HasPrefix(text, "title:") {
				ret.title = strings.Trim(strings.TrimPrefix(text, "title:"), "\" ")
			} else if strings.HasPrefix(text, "description:") {
				ret.description = strings.TrimSpace(strings.TrimPrefix(text, "description:"))
			}
		}
	} else {
		fmt.Fprintln(os.Stderr, err)
	}
	return ret
}

func isHTML(file os.FileInfo) bool {
	return isHTMLFile(file.Name())
}

func isHTMLFile(path string) bool {
	return strings.HasSuffix(path, ".html")
}

func hasDescription(path string) bool {
	metapath := metapath(path)
	if _, err := os.Stat(metapath); os.IsNotExist(err) {
		return false
	} else {
		return true
	}
}

func getSubpages(filename string) []string {
	ret := []string{}
	dirpath := goutil.TrimExt(filename)
	if files, err := ioutil.ReadDir(dirpath); err == nil {
		for _, file := range files {
			if isHTML(file) {
				fullpath := strings.TrimPrefix(strings.TrimPrefix(dirpath, "stage1/"), "stage1\\")
				ret = append(ret, filepath.Join(fullpath, file.Name()))
			}
		}
	}
	return ret
}

func getMetadata(path string) metadata {
	ret := metadata{}
	ret.explicit = getExplicitMetadata(path)
	ret.subpages = getSubpages(path)
	return ret
}

func completePage(path string, t *template.Template, style string, script string) {
	md := getMetadata(path)
	emd := md.explicit
	content, _ := goutil.ReadFile(path)
	page := Page{}
	page.Title = emd.title
	page.Style = style
	page.Script = script
	page.Subpages = md.getSubpages()
	page.Description = emd.description
	page.Content = content
	buf := new(bytes.Buffer)
	err := t.Execute(buf, page)
	if err != nil {
		fmt.Println(err)
	}
	destination := strings.Replace(path, "stage1", "stage2", 1)
	os.Remove(destination) // remove hardlink before writing
	goutil.WriteFile(destination, buf.String())
}

func ignore(path string) bool {
	var ignorePaths = []string{filepath.Join("stage1", "blog") + string(os.PathSeparator)}
	for _, prefix := range ignorePaths {
		if strings.HasPrefix(path, prefix) {
			return true
		}
	}
	return false
}

func traverse(t *template.Template, style string, script string, path string, info os.FileInfo, err error) error {
	if !ignore(path) && isHTMLFile(path) && hasDescription(path) {
		completePage(path, t, style, script)
	}
	return nil
}

func Generate() {
	style, err := goutil.ReadFile("style.css")
	script, err2 := goutil.ReadFile("script.js")
	templateString, err3 := goutil.ReadFile("template")
	t := template.Must(template.New("page").Parse(templateString))
	traverseFunc := func(path string, info os.FileInfo, err error) error {
		return traverse(t, style, script, path, info, err)
	}
	if err == nil && err2 == nil && err3 == nil {
		filepath.Walk("stage1", traverseFunc)
	} else {
		fmt.Println(err)
		fmt.Println(err2)
		fmt.Println(err3)
	}
}