#!/usr/bin/env bash

# ---------------------------------------------------------------------------

# Script   : txt2bin - Convert text files to self-displaying portable Linux binaries
# Usage    : txt2bin input.txt output_name

# Release  : 13 December 2025
# License  : Blue Oak Model License
# Copyright: 640kb.neocities.org

# A fun little script based on the short story: The Council of Linux Greybeards
# https://640kb.neocities.org/short.stories/shorts/the.council.of.linux.greybeards.html

# See why this script exists:
# https://640kb.neocities.org/apps/apps.free/txt2bin-why.html

# ---------------------------------------------------------------------------

# Features:

# - Creates self-displaying files. 80-column or less input is recommended
# - Great for self-displaying ASCII Art
# - Preserves text layout with proper C string escaping
# - Uses musl-gcc for smallest size, falls back to gcc -static
# - Prevents accidental overwrites with safety prompts

# ---------------------------------------------------------------------------

if [[ "$1" == "-h" || "$1" == "--help" ]]; then
    echo
    echo " txt2bin converts text files into self-displaying portable Linux binaries"
    echo
    echo " Usage: txt2bin input.txt output_name  (.c extension is automatically added)"
    echo
    echo " Creates: output_name.bin (a portable Linux executable)"
    echo
    echo " Examples:"
    echo "   txt2bin infile.txt out.txt   # Creates out.txt.bin (via out.txt.c)"
    echo "   txt2bin art.txt picture      # Creates picture.bin (via picture.c)"
    echo
    exit 0
fi

if [ $# -ne 2 ]; then
    echo
    echo " Usage: txt2bin input.txt output_name"
    echo
    echo " For more information: txt2bin -h"
    echo
    exit 1
fi

INPUT="$1"
OUTPUT_BASE="$2"
OUTPUT_C="${OUTPUT_BASE}.c"
OUTPUT_BIN="${OUTPUT_BASE}.bin"

if [ "$INPUT" = "$OUTPUT_C" ] || [ "$INPUT" = "$OUTPUT_BIN" ]; then
    echo
    echo " Error: Input file cannot have the same name as output files"
    echo " This would overwrite your source file!"
    echo
    exit 1
fi

if [ -f "$OUTPUT_BIN" ]; then
    read -p "Warning: $OUTPUT_BIN already exists. Overwrite? (y/N) " -n 1 -r
    echo
    if [[ ! $REPLY =~ ^[Yy]$ ]]; then
        echo " Aborted. Please choose a different output name."
        exit 1
    fi
    rm -f "$OUTPUT_BIN"
fi

if [ -f "$OUTPUT_C" ]; then
    read -p "Warning: $OUTPUT_C already exists. Overwrite? (y/N) " -n 1 -r
    echo
    if [[ ! $REPLY =~ ^[Yy]$ ]]; then
        echo "Aborted. Please choose a different output name."
        exit 1
    fi
    rm -f "$OUTPUT_C"
fi

generate_c_source() {
    echo '#include <stdio.h>'
    echo ''
    echo 'int main(void) {'
    echo '    printf('
    sed 's/["\]/\\&/g; s/^/    "/; s/$/\\n"/' "$INPUT"
    echo '    );'
    echo '    return 0;'
    echo '}'
}

compile_with_fallback() {
    local compiler="$1"
    local flags="$2"
    local method="$3"
    
    echo -n " Compiling with $compiler... "
    
    if $compiler $flags -o "$OUTPUT_BIN" "$OUTPUT_C"; then
        # echo "   ($method)"
        echo
        echo "   Created: $OUTPUT_BIN"
        echo "   Size: $(stat -c%s "$OUTPUT_BIN") bytes"
        return 0
    else
        echo " Failed"
        return 1
    fi
}

echo
echo " Generating C source..."
generate_c_source > "$OUTPUT_C" || { echo "Error creating $OUTPUT_C"; exit 1; }
echo "   Created: $OUTPUT_C"
echo

if command -v musl-gcc >/dev/null 2>&1; then
    if ! compile_with_fallback "musl-gcc" "-static" "musl static"; then
        echo "  musl-gcc failed, trying standard gcc..."
        if compile_with_fallback "gcc" "-static" "glibc static"; then
            echo "  (Note: glibc static binaries are much larger)"
        fi
    fi
elif compile_with_fallback "gcc" "-static" "glibc static"; then
    :
else
    echo "  Compilation failed: Could not create static binary"
    exit 1
fi

echo
echo " The Linux portable binary is ready..."
echo "   Run it: ./$OUTPUT_BIN"
echo