#!/bin/bash
cd "$(dirname "$0")"
cd ..

BUILDMODE=${2:-"debug"}
OPT_FLAG="O0"
GF="uce_fastcgi"

mkdir bin > /dev/null 2>&1
mkdir bin/tmp > /dev/null 2>&1
mkdir bin/assets > /dev/null 2>&1
mkdir bin/wasm > /dev/null 2>&1
mkdir work > /dev/null 2>&1

COMPILER="clang++"
# -rdynamic is a link-time flag; the -c compiles below do not need it.
FLAGS="-g -w -Wall -$OPT_FLAG -std=c++20 -fpermissive -ffast-math"

# Wasmtime C++ API — needed only by the wasm backend object (src/wasm).
WASMTIME_HOME=${WASMTIME_HOME:-/opt/wasmtime}
WASM_FLAGS="-I$WASMTIME_HOME/include"
WASM_LIBS="-L$WASMTIME_HOME/lib -Wl,-rpath,$WASMTIME_HOME/lib -lwasmtime"

LIBS="-ldl -lm -lpthread -lpcre2-8 `mysql_config --cflags --libs` $WASM_LIBS"
SRCFLAGS="-D EXEC_NAME=\"$GF\" -D PLATFORM_NAME=\"linux\""

# The runtime is split into separately-compiled objects so an edit to one
# module no longer recompiles the others (notably: editing the wasm backend
# does not recompile the rest, and vendored SQLite is built once):
#   bin/sqlite3.o  vendored SQLite amalgamation (depends only on its own source)
#   bin/wasm.o     wasm backend + worker + wasmtime.hh (src/wasm)
#   bin/main.o     linux_fastcgi.cpp + the uce_lib core amalgamation
# All link into the single -rdynamic binary. Delete bin/*.o to force a clean
# rebuild.

# Rebuild $1 if it is missing or anything under the remaining find-args is newer.
needs_rebuild() {
	local obj="$1"; shift
	[ ! -f "$obj" ] && return 0
	[ -n "$(find "$@" -newer "$obj" -print -quit 2>/dev/null)" ] && return 0
	return 1
}

# core.wasm: guest runtime loaded by the native wasm backend.
if needs_rebuild bin/wasm/core.wasm src/wasm/core.cpp src/lib src/wasm/core_hostcalls.syms src/wasm/core_libc_exports.syms scripts/build_core_wasm.sh; then
	echo "Compiling wasm core..."
	bash scripts/build_core_wasm.sh || exit 1
else
	echo "Reusing bin/wasm/core.wasm"
fi

# SQLite: vendored C, depends only on its own source (not our headers).
if needs_rebuild bin/sqlite3.o src/3rdparty/sqlite/sqlite3.c src/3rdparty/sqlite/sqlite3.h; then
	echo "Compiling SQLite..."
	clang -g -O2 -fPIC \
		-DSQLITE_THREADSAFE=1 \
		-DSQLITE_OMIT_LOAD_EXTENSION=1 \
		-DSQLITE_DQS=0 \
		-DSQLITE_DEFAULT_FOREIGN_KEYS=1 \
		-DSQLITE_DEFAULT_WAL_SYNCHRONOUS=1 \
		-c src/3rdparty/sqlite/sqlite3.c -o bin/sqlite3.o 2>&1 || exit 1
else
	echo "Reusing bin/sqlite3.o"
fi

# wasm backend object: the wasm sources plus the lib headers it includes for
# declarations (not the lib .cpp — those are compiled into main.o).
if needs_rebuild bin/wasm.o src/wasm src/lib/*.h; then
	echo "Compiling wasm backend..."
	time -p $COMPILER -c src/wasm/wasm_module.cpp $SRCFLAGS $FLAGS $WASM_FLAGS -o bin/wasm.o 2>&1 || exit 1
else
	echo "Reusing bin/wasm.o"
fi

# main object: the FastCGI entrypoint + the uce_lib core amalgamation. Depends
# on linux_fastcgi.cpp, the whole lib tree, fcgicc, and the wasm backend header
# (its only view of the wasm object) — but not the wasm .cpp sources.
if needs_rebuild bin/main.o src/linux_fastcgi.cpp src/lib src/fastcgi src/wasm/backend.h; then
	echo "Compiling main..."
	time -p $COMPILER -c src/linux_fastcgi.cpp $SRCFLAGS $FLAGS -o bin/main.o 2>&1 || exit 1
else
	echo "Reusing bin/main.o"
fi

echo "Linking..."
$COMPILER -rdynamic bin/main.o bin/wasm.o bin/sqlite3.o $FLAGS $LIBS -o bin/$GF.linux.bin 2>&1

if [ $? -eq 0 ]
then
	ls -lh bin/ | grep $GF
	exit 0
else
	exit 1
fi