package main

import (
	"encoding/json"
	"html/template"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"path"
	"strconv"
	"strings"

	"github.com/russross/blackfriday"
)

func main() {
	if err := loadConfig(); err != nil {
		log.Fatal(`Failed to load config. ` + err.Error())
	}

	if err := updateTemplate(); err != nil {
		log.Fatal(`Failed to load template. ` + err.Error())
	}

	log.Fatal(http.ListenAndServe(":"+strconv.Itoa(config.Port), http.HandlerFunc(serveRequest)))
}

var config struct {
	Port     int    `json:"port"`
	Template string `json:"template"`
}

func loadConfig() error {
	f, err := os.Open(`config.json`)
	if err != nil && !os.IsNotExist(err) {
		return err
	}

	// Set defaults
	config.Port = 80
	config.Template = `template.html`

	if err != nil {
		return
	}

	err = json.NewDecoder(f).Decode(&config)
	if err != nil {
		return err
	}
}

var t *template.Template

func updateTemplate() error {
	var err error
	t, err = template.ParseFiles(config.Template)
	if err != nil {
		return err
	}
	return nil
}

func serveRequest(w http.ResponseWriter, r *http.Request) {
	if strings.HasPrefix(r.URL.Path, `/static/`) {
		p, _ := os.Getwd()
		p = path.Join(p, r.URL.Path)
		http.ServeFile(w, r, p)
		return
	}
	servePage(w, r)
}

func servePage(w http.ResponseWriter, r *http.Request) {
	p := `pages` + path.Clean(r.URL.Path)

	s, err := os.Stat(p)
	if err != nil {
		w.WriteHeader(404)
		return
	}
	if s.IsDir() {
		if p[len(p)-1] != '/' {
			p += `/`
		}
		p += `index`
	}

	c, err := ioutil.ReadFile(p + `.md`)
	if err != nil {
		w.WriteHeader(404)
		return
	}

	t.Execute(w, template.HTML(blackfriday.MarkdownCommon(c)))
}