package main

import (
	"flag"
	"io/ioutil"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"

	"gopkg.in/yaml.v2"
)

// Assumes we're getting a pageName ending in .page
func convertPage(newDir, pageName string) error {
	yamlName := pageName[:len(pageName)-5] + ".yml"
	headName := pageName[:len(pageName)-5] + ".head"
	newPageName := pageName[:len(pageName)-5] + ".md"
	hasHead := false
	headBytes := []byte{}
	if _, err := os.Stat(headName); err == nil {
		hasHead = true
	}

	if hasHead {
		var err error
		headBytes, err = ioutil.ReadFile(headName)
		if err != nil {
			return err
		}
	}

	y, err := yaml.Marshal(map[string]string{
		"head": string(headBytes),
	})
	if err != nil {
		return err
	}

	cmd := exec.Command("mkdir", "-p", filepath.Join(newDir, filepath.Dir(pageName)))
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	err = cmd.Run()
	if err != nil {
		return err
	}
	cmd = exec.Command("cp", "-v", pageName, filepath.Join(newDir, newPageName))
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	err = cmd.Run()
	if err != nil {
		return err
	}

	if len(headBytes) == 0 {
		return nil
	} else {
		return ioutil.WriteFile(newDir+"/"+yamlName, y, 0644)
	}
}

func main() {
	fl := flag.NewFlagSet("Website converter", flag.ExitOnError)
	origDirectory := fl.String("d", ".", "Directory to read from")
	newDirectory := fl.String("D", ".", "Directory to write to")
	_ = fl.Parse(os.Args[1:])

	newDir, _ := filepath.Abs(*newDirectory)
	origDir, _ := filepath.Abs(*origDirectory)

	if err := os.Chdir(origDir); err != nil {
		log.Fatal(err)
	}

	pageRe := regexp.MustCompile(`\.page$`)
	_ = filepath.Walk(".", func(path string, info os.FileInfo, err error) error {
		if err != nil {
			// Prevents panic
			log.Println(err)
			return err
		}

		if pageRe.MatchString(info.Name()) {
			if err := convertPage(newDir, path); err != nil {
				log.Println(err)
				return err
			}
		}

		return nil
	})

}