The Telegram Problem

README.md

Implement the function handle to accept lines of text and output reformatted text, wrapped at columnWidth characters, without breaking words.

So

Yr brunch Godard, readymade pug Pinterest gastropub put a bird on it Tumblr.
Sartorial swag beard, selvage bitters tofu vinyl.
Tattooed kogi organic scenester heirloom, cred four loko cardigan cray meh Portland master cleanse photo booth Shoreditch farm-to-table.

when wrapped at 30 characters becomes

Yr brunch Godard, readymade  
pug Pinterest gastropub put a  
bird on it Tumblr. Sartorial  
swag beard, selvage bitters  
tofu vinyl. Tattooed kogi  
organic scenester heirloom,  
cred four loko cardigan cray  
meh Portland master cleanse  
photo booth Shoreditch  
farm-to-table.  

Breaking like this:

Yr brunch Godard, readymade pu  
g Pinterest gastropub put a bi  
rd on it Tumblr. Sartorial swa  
g beard, selvage bitters tofu   
vinyl. Tattooed kogi organic s  
cenester heirloom, cred four l  
oko cardigan cray meh Portland  
 master cleanse photo booth Sh  
oreditch farm-to-table.  

is incorrect.

main.go

package main

import (
	"bufio"
	"os"
	"strconv"
)

var columnWidth uint64 // How long each line should be

func handle(line string) {
	// Implement this!
}

func main() {
	columnWidth, _ = strconv.ParseUint(os.Args[1], 10, 8)

	input := bufio.NewReader(os.Stdin)

	for line, err := input.ReadString('\n'); err == nil; line, err = input.ReadString('\n') {
		handle(line)
	}
}

var result []string

func handle(line string) {
    line = strings.Replace(line, "\n", "", -1)
    words := strings.Split(line, " ")

    for _, word := range words {
        if len(result)+len(word) <= int(columnWidth) {
            result = append(result, word)
        }
    }

    fmt.Println("\n")
    fmt.Println("======================")
    fmt.Printf("%+v\n", result)
    fmt.Printf("%+v\n", len(result))
    fmt.Println("======================")
}

package main

import (
    "fmt"
    "strings"
)

func Handle(text string) (result string) {
    columnWidth := 30
    textWithBreakLine := strings.Replace(text, "\n", " ", -1)
    words := strings.Split(textWithBreakLine, " ")

    newLine := ""
    extraWord := ""
    for _, w := range words {
        if extraWord != "" {
            newLine += extraWord + " "
            extraWord = ""
        }
        originLine := newLine

        if len(newLine) <= columnWidth {
            newLine += w + " "
            if len(newLine) > columnWidth {
                result += originLine + "\n"
                extraWord = w
                newLine = ""
            }
        }
    }
    if extraWord != "" {
        result += extraWord + "\n"
    }
    return result
}

func main() {
    text := `Yr brunch Godard, readymade pug Pinterest gastropub put a bird on it Tumblr.
Sartorial swag beard, selvage bitters tofu vinyl.
Tattooed kogi organic scenester heirloom, cred four loko cardigan cray meh Portland master cleanse photo booth Shoreditch farm-to-table.`

    fmt.Print(Handle(text))
}

TEST

package main

import (
    "strings"
    "testing"
)

func TestHandle(t *testing.T) {
    text := `Yr brunch Godard, readymade pug Pinterest gastropub put a bird on it Tumblr.
Sartorial swag beard, selvage bitters tofu vinyl.
Tattooed kogi organic scenester heirloom, cred four loko cardigan cray meh Portland master cleanse photo booth Shoreditch farm-to-table.`
    result := Handle(text)
    originOneLineText := strings.Replace(text, "\n", " ", -1)
    oneLineResult := strings.Replace(result, "\n", " ", -1)
    oneLineResult = strings.Trim(strings.Replace(oneLineResult, "  ", " ", -1), " ")

    if originOneLineText != oneLineResult {
        t.Errorf("Error")
    }

    lines := strings.Split(result, "\n")
    for _, l := range lines {
        if len(l) > 30 {
            t.Errorf("Error")
        }
    }
}

package main

import (
    "bufio"
    "fmt"
    // "strconv"
    "strings"
)

func main() {
    max := 30

    var input = `
Yr brunch Godard, readymade pug Pinterest gastropub put a bird on it Tumblr.
Sartorial swag beard, selvage bitters tofu vinyl.
Tattooed kogi organic scenester heirloom, cred four loko cardigan cray meh Portland master cleanse photo booth Shoreditch farm-to-table.
    `

    scanner := bufio.NewScanner(strings.NewReader(input))
    // Create a custom split function by wrapping the existing ScanWords function.
    split := func(data []byte, atEOF bool) (advance int, token []byte, err error) {
        // if len(data) >= max {
        //  advance = max
        //  token = data
        // }
        token = data[:max]
        li := strings.LastIndex(string(token), " ")
        if li != 0 {
            max = li
        }
        token = data[:max]
        advance = max
        // fmt.Println("data = ", string(data))
        // fmt.Println("atEOF = ", atEOF)
        return
    }

    // Set the split function for the scanning operation.
    scanner.Split(split)
    // Validate the input
    for scanner.Scan() {
        fmt.Printf("%s\n", scanner.Text())
    }

    if err := scanner.Err(); err != nil {
        fmt.Printf("Invalid input: %s", err)
    }

}

https://gist.github.com/jinzhu/371ee98051e0f661de39

BUG 1:
When run juice's program with:

go run main.go 1000

input is:

Yr brunch Godard, readymade pug Pinterest gastropub put a bird on it Tumblr. Sartorial swag beard, selvage bitters tofu vinyl. Tattooed kogi organic scenester heirloom, cred four loko cardigan cray meh Portland master cleanse photo booth Shoreditch

OUTPUT:

Yr 
brunch 
Godard, 
readymade 
pug 
Pinterest 
gastropub 
put 
a 
bird 
on 
it 
Tumblr. 
Sartorial 
swag 
beard, 
selvage 
bitters 
tofu 
vinyl. 
Tattooed 
kogi 
organic 
scenester 
heirloom, 
cred 
four 
loko 
cardigan 
cray 
meh 
Portland 
master 
cleanse 
photo 
booth 

BUG 2:

run go main.go 30

INPUT:

Yr brunch Godard, readymade pug Pinterest gastropub put a bird on it Tumblr. Sartorial swag beard, selvage bitters tofu vinyl. Tattooed kogi organic scenester heirloom, cred four loko cardigan cray meh Portland master cleanse photo booth Shoreditch farm-to-table.

OUTPUT:

Yr brunch Godard, readymade
pug Pinterest gastropub put a
bird on it Tumblr. Sartorial
swag beard, selvage bitters
tofu vinyl. Tattooed kogi
organic scenester heirloom,
cred four loko cardigan cray
meh Portland master cleanse
photo booth Shoreditch

farm-to-table.

The result doesn't come out at once, need to click Enter again. Actually it's not correct ;)

BUG:

run go main.go 5

INPUT:

Yr brunch Godard, readymade pug Pinterest gastropub put a bird on it Tumblr. Sartorial swag beard, selvage bitters tofu vinyl. Tattooed kogi organic scenester heirloom, cred four loko cardigan cray meh Portland master cleanse photo booth Shoreditch farm-to-table.

OUTPUT:

Yr
brunch
Godard,
readymade
pug
Pinterest
gastropub
put
a
bird
on
it
Tumblr.
Sartorial
swag
beard,
selvage
bitters
tofu
vinyl.
Tattooed
kogi
organic
scenester
heirloom,
cred
four
loko
cardigan
cray
meh
Portland
master
cleanse
photo
booth
Shoreditch

farm-to-table.