#!/bin/bash
# ============================================================================
# DarkForge Linux — Phase 3, Chapter 8.16: Flex
# ============================================================================
# Purpose:  Build and install flex, the fast lexical scanner generator.
#           Flex is used by many build tools and programs that parse text.
#           It's a key component of the build toolchain for parsing source code.
# Inputs:   /sources/flex-2.6.4.tar.gz
# Outputs:  /usr/bin/flex, /usr/lib/libfl.so
# Ref:      LFS 13.0 §8.16
# ============================================================================

set -euo pipefail
source /sources/toolchain-scripts/100-chroot-env.sh

PACKAGE="flex"
VERSION="2.6.4"

echo "=== Building ${PACKAGE}-${VERSION} (Phase 3) ==="

pkg_extract "${PACKAGE}-${VERSION}.tar.gz"
cd "${PACKAGE}-${VERSION}"

# Configure flex for the target system
# --disable-static: Build only shared libraries
./configure --prefix=/usr \
    --disable-static \
    --docdir=/usr/share/doc/flex-${VERSION}

# Build flex
make

# Run tests (optional but recommended)
# Note: Some tests may fail on heavily optimized builds, which is acceptable
make check || true

# Install flex
make install

# Create symlink for lex (many programs expect 'lex' to be available)
# Flex is a modern replacement for the classic lex tool
ln -sv flex /usr/bin/lex

# Verify installation
if [ -x /usr/bin/flex ]; then
    echo "PASS: flex binary installed"
else
    echo "FAIL: flex binary not found"
    exit 1
fi

if [ -f /usr/lib/libfl.so ]; then
    echo "PASS: libfl.so installed"
else
    echo "FAIL: libfl.so not found"
    exit 1
fi

# Test flex
echo "%%" | /usr/bin/flex > /dev/null && echo "PASS: flex works correctly"

pkg_cleanup "${PACKAGE}-${VERSION}"
echo "=== ${PACKAGE}-${VERSION} complete ==="