package main

import (
	"bufio"
	"flag"
	"fmt"
	"os"
	"regexp"
	"strings"
	"text/tabwriter"
)

type queue struct {
	q    []string
	maxl int
}

func (q *queue) insert(s string) {
	if len(q.q) <= q.maxl {
		q.q = append(q.q, s)
		return
	}
	q.q = append(q.q[1:len(q.q)], s)
}

type work struct {
	c    chan string
	left int
}

func printWithContext(all []string, ind, ctxlen int) {
	var slice []string
	slice = append(slice, "\""+all[ind]+"\"")

	if len(all[:ind]) < ctxlen {
		slice = append(all[:ind], slice...)
	} else {
		slice = append(all[ind-ctxlen:ind], slice...)
	}

	if len(all[ind:]) < ctxlen {
		slice = append(slice, all[ind+1:]...)
	} else {
		slice = append(slice, all[ind+1:ind+ctxlen]...)
	}

	fmt.Fprintf(tw, "%s\n", strings.Join(slice, "\t"))
}

func feedworkers(wlist []*work, w string) []*work {
	var onefinished bool
	var ret []*work
	for _, wc := range wlist {
		if wc.left == 0 {
			close(wc.c)
			onefinished = true
		}
	}

	if onefinished && len(wlist) > 1 {
		ret = wlist[1:]
	}
	return ret
}

func print_kwic(sl []string, c chan string) {
	for w := range c {
		sl = append(sl, w)
	}
	fmt.Fprintf(tw, "%s\n", strings.Join(sl, "\t"))
}

func printqueue(q *queue, c chan string, left int) {
	var hungryhippos []*work
	for w := range c {
		index := strings.Index(w, kw)
		if index < 0 {
			q.insert(w)
			feedworkers(hungryhippos, w)
			continue
		}

		q.insert(fmt.Sprintf("%q", w))

		fmt.Fprintf(os.Stdout, "%q totally matched %q\n", w, kw)
		fmt.Fprintf(os.Stdout, "queue was %v\n", q.q)

		wc := &work{c: make(chan string), left: 5}

		feedworkers(hungryhippos, w)

		sl := make([]string, MAX)
		n := copy(sl, q.q[6:])
		fmt.Fprintf(os.Stdout, "copied %d : %v\n", n, sl)
		hungryhippos = append(hungryhippos, wc)
		go print_kwic(sl, wc.c)
	}
	for _, wc := range hungryhippos {
		close(wc.c)
	}
}

var (
	tw *tabwriter.Writer
	kw string
)

const MAX int = 11

func main() {
	flag.Parse()
	kw = flag.Arg(0)
	if len(kw) == 0 {
		fmt.Printf("Need string to search for. Exiting...\n")
		os.Exit(1)
	}
	tw = tabwriter.NewWriter(os.Stdout, 1, 1, 1, ' ', 0)
	splitreg := regexp.MustCompile("[ \t\n]")

	q := queue{maxl: MAX, q: make([]string, MAX)}
	sc := make(chan string, 1000)

	reader := bufio.NewReader(os.Stdin)
	line, err := reader.ReadString(byte('\n'))
	go func(c chan string) {
		var w string
		for err == nil {
			splline := splitreg.Split(line, -1)
			for _, w = range splline {
				c <- w
			}
			line, err = reader.ReadString(byte('\n'))
		}
		fmt.Printf("Got an error: %q.\n", err)
		c <- w
		close(c)
	}(sc)

	printqueue(&q, sc, 5)
	//printWithContext(splline, i, 5)
	tw.Flush()
}