/*
 * Copyright (c) 2015 Alex Yatskov <alex@foosoft.net>
 * Author: Alex Yatskov <alex@foosoft.net>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package main

import (
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"os"

	"github.com/russross/blackfriday"
)

func usage() {
	fmt.Fprintf(os.Stderr, "Usage: %s [options] [input] [output]\n", os.Args[0])
	fmt.Fprintf(os.Stderr, "http://foosoft.net/projects/vimdown/\n\n")
	fmt.Fprintf(os.Stderr, "Parameters:\n")
	flag.PrintDefaults()
}
func main() {
	flag.Usage = usage
	flag.Parse()

	args := flag.Args()

	var input []byte
	var err error
	switch len(args) {
	case 0:
		if input, err = ioutil.ReadAll(os.Stdin); err != nil {
			log.Fatal("error reading from stdin")
		}
	case 1, 2:
		if input, err = ioutil.ReadFile(args[0]); err != nil {
			log.Fatalf("error reading from %s", args[0])
		}
	default:
		flag.Usage()
		os.Exit(-1)
	}

	renderer := VimDocRenderer()

	extensions := 0
	extensions |= blackfriday.EXTENSION_NO_INTRA_EMPHASIS
	extensions |= blackfriday.EXTENSION_TABLES
	extensions |= blackfriday.EXTENSION_FENCED_CODE
	extensions |= blackfriday.EXTENSION_AUTOLINK
	extensions |= blackfriday.EXTENSION_STRIKETHROUGH
	extensions |= blackfriday.EXTENSION_SPACE_HEADERS

	output := blackfriday.Markdown(input, renderer, extensions)

	var file *os.File
	switch len(args) {
	case 2:
		if file, err = os.Create(args[1]); err != nil {
			fmt.Fprintf(os.Stderr, "Error creating %s: %v", args[1], err)
			os.Exit(-1)
		}
		defer file.Close()
	default:
		file = os.Stdout
	}

	if _, err = file.Write(output); err != nil {
		log.Fatal("error writing output")
	}
}