ascii-art2

package main

import (
    "bufio"
    "fmt"
    "os"
    "strings"
)

func main() {
    args := ""
    if len(os.Args) == 3 {
        args = string(os.Args[2])
        args = args + ".txt"
    } else if len(os.Args) == 2 {
        args = "font.txt"
    } else {
        fmt.Println("Program uses os.Args as input. To run the program from terminal do it like this: \n\nExample:  go run . 'string you want to print' font")
    }
    if _, err := os.Stat(args); os.IsNotExist(err) {
        fmt.Println("Program uses os.Args as input. To run the program from terminal do it like that: \n\nExample:  go run . 'string you want to print' font")
        os.Exit(0)
    }

    font, _ := readLines(args)
    text := os.Args[1]
    textLines := strings.Split(text, "\\n")

    writeText(textLines, font)
}

// This function prints the lines
func writeText(textLines []string, font []string) {
    for i := 0; i < len(textLines); i++ {
        x := 0
        for j := 0; j < 8; j++ {
            for k := 0; k < len(textLines[i]); k++ {
                // Find the right line for the letter
                pos := 1 + (int(textLines[i][k])-32)*9 + x
                fmt.Printf(font[pos])
            }
            x++
            fmt.Println()
        }
    }
}

// This function reads the font file
func readLines(path string) ([]string, error) {
    file, err := os.Open(path)
    if err != nil {
        return nil, err
    }
    defer file.Close()

    var lines []string
    scanner := bufio.NewScanner(file)
    for scanner.Scan() {
        lines = append(lines, scanner.Text())
    }
    return lines, scanner.Err()
}