package main

import (
	diff "0dev.org/diff"
	"bufio"
	"flag"
	"fmt"
	"hash"
	"hash/fnv"
	"io"
	"os"
)

const usage = "Usage: plaindiff <file1> <file2>"

func main() {
	flag.Parse()

	var args []string = flag.Args()
	if len(args) != 2 {
	var args []string = os.Args
	if len(args) != 3 {
		os.Stderr.WriteString(usage)
		os.Exit(1)
	}

	var hd hashDiff
	hd.hash = fnv.New64a()
	hd.first = read(args[0], hd.hash)
	hd.second = read(args[1], hd.hash)
	hd.first = read(args[1], hd.hash)
	hd.second = read(args[2], hd.hash)

	var result diff.Delta = diff.Diff(&hd)

	gen := source(result)
	out := bufio.NewWriter(os.Stdout)
	for have, added, mark := gen(); have; have, added, mark = gen() {
		var from []line = hd.line(!added)

		fmt.Println()
		fmt.Fprintln(out)
		for i := mark.From; i < mark.Length; i++ {
			fmt.Print(i)
			fmt.Fprint(out, i)
			if added {
				fmt.Print(" > ")
				fmt.Fprint(out, " > ")
			} else {
				fmt.Print(" < ")
				fmt.Fprint(out, " < ")
			}
			fmt.Println(from[i].text)
			fmt.Fprintln(out, from[i].text)
		}
	}

	out.Flush()
}

// Returns a closure over the provided diff.Delta
// that returns diff.Mark entries while prioritizing removals when possible
func source(d diff.Delta) func() (bool, bool, diff.Mark) {
	var addedAt, removedAt int = 0, 0
	return func() (bool, bool, diff.Mark) {