#!/usr/bin/env bash
set -euo pipefail

# Configuration
TARGET="i386-elf"
BINUTILS_VERSION="2.45"
GCC_VERSION="15.2.0"

# Paths
SCRIPT_PATH="$(realpath "${BASH_SOURCE[0]}")"
SCRIPT_DIR="$(dirname "$SCRIPT_PATH")"
PREFIX="$SCRIPT_DIR/cross"
SRC_DIR="$PREFIX/src"

BINUTILS_SRC="$SRC_DIR/binutils-$BINUTILS_VERSION"
BINUTILS_BUILD="$PREFIX/build-binutils"
GCC_SRC="$SRC_DIR/gcc-$GCC_VERSION"
GCC_BUILD="$PREFIX/build-gcc"

# Flags
DEBUG=0
HELP=0

# Parse arguments
for arg in "$@"; do
  case "$arg" in
    -h|--help)
      HELP=1
      ;;
    -d|--debug)
      DEBUG=1
      ;;
    *)
      echo "Unknown option: $arg"
      echo "Use -h or --help for usage information"
      exit 1
      ;;
  esac
done

# Show help
if [[ "$HELP" -eq 1 ]]; then
  cat << EOF
Usage: $0 [OPTIONS]

Build a cross-compiler toolchain for $TARGET.

OPTIONS:
  -h, --help     Show this help message
  -d, --debug    Enable debug mode (set -x)

This script will:
  1. Download binutils $BINUTILS_VERSION and GCC $GCC_VERSION
  2. Build and install them to: $PREFIX

EOF
  exit 0
fi

# Enable debug mode
if [[ "$DEBUG" -eq 1 ]]; then
  set -x
fi

# Print configuration
cat << EOF

=== Build Configuration ===
Target       : $TARGET
Prefix       : $PREFIX
Binutils     : $BINUTILS_VERSION
GCC          : $GCC_VERSION
===========================

EOF

# Create directory structure
echo "Setting up directories..."
mkdir -p "$SRC_DIR"

# Download sources
cd "$SRC_DIR"

if [[ ! -d "$BINUTILS_SRC" ]]; then
  echo "Downloading binutils $BINUTILS_VERSION..."
  wget "https://ftp.gnu.org/gnu/binutils/binutils-$BINUTILS_VERSION.tar.gz"
  echo "Extracting binutils..."
  tar xf "binutils-$BINUTILS_VERSION.tar.gz"
  rm "binutils-$BINUTILS_VERSION.tar.gz"
else
  echo "Binutils source already exists, skipping download"
fi

if [[ ! -d "$GCC_SRC" ]]; then
  echo "Downloading GCC $GCC_VERSION..."
  wget "https://ftp.gnu.org/gnu/gcc/gcc-$GCC_VERSION/gcc-$GCC_VERSION.tar.gz"
  echo "Extracting GCC..."
  tar xf "gcc-$GCC_VERSION.tar.gz"
  rm "gcc-$GCC_VERSION.tar.gz"
else
  echo "GCC source already exists, skipping download"
fi

# Download GCC prerequisites
if [[ ! -d "$GCC_SRC/gmp" ]]; then
  echo "Downloading GCC prerequisites..."
  cd "$GCC_SRC"
  ./contrib/download_prerequisites
  cd "$SRC_DIR"
else
  echo "GCC prerequisites already downloaded, skipping"
fi

# Build binutils
if [[ ! -f "$PREFIX/bin/$TARGET-ld" ]]; then
  echo "Building binutils..."
  mkdir -p "$BINUTILS_BUILD"
  cd "$BINUTILS_BUILD"

  "$BINUTILS_SRC/configure" \
    --target="$TARGET" \
    --prefix="$PREFIX" \
    --with-sysroot \
    --disable-nls \
    --disable-werror

  make -j"$(nproc)"
  make install
else
  echo "Binutils already installed, skipping build"
fi

# Build GCC
if [[ ! -f "$PREFIX/bin/$TARGET-gcc" ]]; then
  echo "Building GCC..."
  mkdir -p "$GCC_BUILD"
  cd "$GCC_BUILD"

  "$GCC_SRC/configure" \
    --target="$TARGET" \
    --prefix="$PREFIX" \
    --disable-nls \
    --enable-languages=c \
    --without-headers

  make all-gcc -j"$(nproc)"
  make all-target-libgcc -j"$(nproc)"
  make install-gcc
  make install-target-libgcc
else
  echo "GCC already installed, skipping build"
fi

cd "$SCRIPT_DIR"

# Generate .build.env file
cat > .build.env << EOF
# Generated by configure on $(date)
# Source this file to add the cross-compiler toolchain to your PATH
export PATH="$PREFIX/bin:\$PATH"
EOF

echo ""
echo "=== Build Complete ==="
echo "Toolchain installed to: $PREFIX"
echo ""
echo "To use the toolchain, run:"
echo "  source .build.env"
echo "======================"