#!/usr/bin/env bash

# ---------------------------------------------------------------------------
# Script   : txt2bin - Convert text file to portable Linux binary with stdout
                       
# Usage    : txt2bin input.txt output_name

# Release  : 13 Dec 2025
# Update   : 12 Aug 2026 - Size-Optimized Binary (from ~16kb to ~5kb)
# 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
# ---------------------------------------------------------------------------

if [[ "$1" == "-h" || "$1" == "--help" ]]; then
    echo
    echo " ---------------------------------------------------------------------------"
    echo " txt2bin converts text files into self-displaying portable Linux binaries"
    echo
    echo " Usage   : txt2bin input.txt output_name  (.c extension 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 asciiart.txt art     # Creates art.bin (via art.c)"
    echo " ---------------------------------------------------------------------------"
    echo " Features:"
    echo 
    echo " - NEW: Size Optimizations (printf replaced with write(); compiler flags)"
    echo " - 80x25 input works best"
    echo " - Falls back to gcc if musl-gcc unavailable"
    echo " - Prevents accidental overwrites with safety prompts"
    echo " - Directly replaces \"cat file.txt\" (who wants to type all of that anyway?)"
    echo " - Keep your deep thoughts safe from malicious edits designed to mock them"
    echo " - Monetize open standards using a vendor lock-in technique"
    echo " - Subscriptions & spyware coming soon..."
    echo " ---------------------------------------------------------------------------"
    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 <unistd.h>'
    echo ''
    echo 'int main(void) {'
    echo '    const char text[] = R"('
    cat "$INPUT"
    echo ''
    echo ')";'
    echo '    write(1, text, sizeof(text) - 1);'
    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
        echo "   Created: $OUTPUT_BIN"
        echo "   Size: $(stat -c%s "$OUTPUT_BIN") bytes"
        return 0
    else
        echo " Failed"
        return 1
    fi
}

echo
echo " Generating minimal C source (using write() syscall)..."
generate_c_source > "$OUTPUT_C" || { echo "Error creating $OUTPUT_C"; exit 1; }
echo "   Created: $OUTPUT_C"
echo

SIZE_FLAGS="-Os -s -ffunction-sections -fdata-sections -Wl,--gc-sections -no-pie"

if command -v musl-gcc >/dev/null 2>&1; then
    if ! compile_with_fallback "musl-gcc" "-static $SIZE_FLAGS" "musl static (minimal)"; then
        echo "  musl-gcc failed, trying standard gcc..."
        if compile_with_fallback "gcc" "-static $SIZE_FLAGS" "glibc static (larger)"; then
            echo "  (Note: glibc static binaries are larger than musl)"
        fi
    fi
elif compile_with_fallback "gcc" "-static $SIZE_FLAGS" "glibc static (larger)"; then
    :
else
    echo "  Compilation failed: Could not create static binary"
    echo "  Please install musl-tools (for musl-gcc) or build-essential (for gcc)"
    exit 1
fi

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