#!/usr/bin/env bash
set -e

# Nexus Rumpk Build Script v0.4
# "Split Brain" Networking Edition

RUMPK_DIR=$(pwd)
BUILD_DIR="$RUMPK_DIR/build"
mkdir -p "$BUILD_DIR"

export ZIG_GLOBAL_CACHE_DIR="$BUILD_DIR/.zig-cache"
export ZIG_LOCAL_CACHE_DIR="$BUILD_DIR/.zig-cache-local"

ARCH=${1:-riscv64}

case $ARCH in
    riscv64)
        ZIG_TARGET="riscv64-freestanding-none"
        ZIG_OBJ_FLAGS="-mcpu=sifive_u54 -mcmodel=medany"
        ARCH_FLAGS="-mcpu=sifive_u54 -mabi=lp64d -mcmodel=medany -ffunction-sections -fdata-sections"
        NIM_CPU="riscv64"
        NIM_DEFINE="riscv64"
        ENTRY_FILE="riscv"
        ;;
    x86_64)
        ZIG_TARGET="x86_64-freestanding-none"
        ARCH_FLAGS="-mno-red-zone"
        NIM_CPU="amd64"
        NIM_DEFINE="x86_64"
        ENTRY_FILE="x86_64"
        ;;
    aarch64)
        ZIG_TARGET="aarch64-freestanding-none"
        ARCH_FLAGS=""
        NIM_CPU="arm64"
        NIM_DEFINE="aarch64"
        ENTRY_FILE="aarch64"
        ;;
    *)
        echo "Unsupported architecture: $ARCH"
        exit 1
        ;;
esac

echo "╔═══════════════════════════════════════╗"
echo "║    RUMPK MULTI-ARCH BUILD v0.4        ║"
echo "║    Architecture: $ARCH                 "
echo "╚═══════════════════════════════════════╝"

# =========================================================
# Step 1: Compile Zig L0 (HAL + libc stubs)
# =========================================================
echo "[1/8] Compiling Zig L0 (HAL + libc stubs)..."
zig build-obj \
    -target $ZIG_TARGET \
    $ZIG_OBJ_FLAGS \
    -O ReleaseFast \
    "$RUMPK_DIR/hal/entry_$ENTRY_FILE.zig" \
    --name hal

mv hal.o "$BUILD_DIR/hal.o"
echo "      → $BUILD_DIR/hal.o"

zig build-obj \
    -target $ZIG_TARGET \
    $ZIG_OBJ_FLAGS \
    -O ReleaseFast \
    "$RUMPK_DIR/hal/stubs.zig" \
    --name stubs

mv stubs.o "$BUILD_DIR/stubs.o"
echo "      → $BUILD_DIR/stubs.o"

zig build-obj \
    -target $ZIG_TARGET \
    $ZIG_OBJ_FLAGS \
    -O ReleaseFast \
    "$RUMPK_DIR/hal/channel.zig" \
    --name channel

mv channel.o "$BUILD_DIR/channel.o"
echo "      → $BUILD_DIR/channel.o"

# Compile NexShell NPL (Immune System Voice)
echo "[1.1/8] Compiling NexShell NPL..."
zig build-obj \
    -target $ZIG_TARGET \
    $ZIG_OBJ_FLAGS \
    -O ReleaseFast \
    "$RUMPK_DIR/src/npl/system/nexshell.zig" \
    --name nexshell

mv nexshell.o "$BUILD_DIR/nexshell.o"
echo "      → $BUILD_DIR/nexshell.o"

# =========================================================
# Step 2: Compile context switch assembly
# =========================================================
echo "[2/8] Compiling context switch ($ARCH)..."
zig cc \
    -target $ZIG_TARGET \
    $ARCH_FLAGS \
    -ffreestanding \
    -c "$RUMPK_DIR/hal/arch/$ARCH/switch.S" \
    -o "$BUILD_DIR/switch.o"
echo "      → $BUILD_DIR/switch.o"

# =========================================================
# Step 2.1: Compile Monocypher
# =========================================================
echo "[2.1/8] Compiling Monocypher..."
zig cc \
    -target $ZIG_TARGET \
    -ffreestanding \
    -fno-stack-protector \
    -fno-builtin \
    -O3 \
    -c "$RUMPK_DIR/hal/crypto/monocypher.c" \
    -o "$BUILD_DIR/monocypher.o"
echo "      → $BUILD_DIR/monocypher.o"

# =========================================================
# Step 2.2: Compile LwIP (Kernel Stack)
# =========================================================
# echo "[2.2/8] Compiling LwIP (Kernel)..."
# LWIP_CORE_FILES=(
#     "src/core/init.c"
#     "src/core/def.c"
#     "src/core/dns.c"
#     "src/core/inet_chksum.c"
#     "src/core/ip.c"
#     "src/core/mem.c"
#     "src/core/memp.c"
#     "src/core/netif.c"
#     "src/core/pbuf.c"
#     "src/core/raw.c"
#     "src/core/stats.c"
#     "src/core/sys.c"
#     "src/core/tcp.c"
#     "src/core/tcp_in.c"
#     "src/core/tcp_out.c"
#     "src/core/timeouts.c"
#     "src/core/udp.c"
#     "src/core/ipv4/autoip.c"
#     "src/core/ipv4/dhcp.c"
#     "src/core/ipv4/etharp.c"
#     "src/core/ipv4/icmp.c"
#     "src/core/ipv4/igmp.c"
#     "src/core/ipv4/ip4.c"
#     "src/core/ipv4/ip4_addr.c"
#     "src/core/ipv4/ip4_frag.c"
#     "src/netif/ethernet.c"
# )
# 
# for cfile in "${LWIP_CORE_FILES[@]}"; do
#     cfile_path="$RUMPK_DIR/vendor/lwip/$cfile"
#     objname=$(basename "$cfile" .c)
#     zig cc \
#         -target $ZIG_TARGET \
#         $ARCH_FLAGS \
#         -ffreestanding \
#         -fno-stack-protector \
#         -fno-builtin \
#         -O2 \
#         -I"$RUMPK_DIR/core/include" \
#         -I"$RUMPK_DIR/core/net" \
#         -I"$RUMPK_DIR/vendor/lwip/src/include" \
#         -c "$cfile_path" \
#         -o "$BUILD_DIR/lwip_kernel_$objname.o"
# done

# =========================================================
# Step 2.3: Compile LwIP (Membrane Stack)
# =========================================================
echo "[2.3/8] Compiling LwIP (Membrane)..."
for cfile in "${LWIP_CORE_FILES[@]}"; do
    cfile_path="$RUMPK_DIR/vendor/lwip/$cfile"
    objname=$(basename "$cfile" .c)
    zig cc \
        -target $ZIG_TARGET \
        $ARCH_FLAGS \
        -ffreestanding \
        -fno-stack-protector \
        -fno-builtin \
        -O2 \
        -I"$RUMPK_DIR/core/include" \
        -I"$RUMPK_DIR/core/net" \
        -I"$RUMPK_DIR/libs/membrane/include" \
        -I"$RUMPK_DIR/vendor/lwip/src/include" \
        -c "$cfile_path" \
        -o "$BUILD_DIR/lwip_membrane_$objname.o"
done
LWIP_MEMBRANE_OBJS=$(ls $BUILD_DIR/lwip_membrane_*.o)

# Compile sys_arch.c (LwIP Platform Abstraction)
echo "[2.4/8] Compiling LwIP Platform Layer (sys_arch.c)..."
# zig cc \
#     -target $ZIG_TARGET \
#     $ARCH_FLAGS \
#     -ffreestanding \
#     -fno-stack-protector \
#     -fno-builtin \
#     -O2 \
#     -I"$RUMPK_DIR/core/include" \
#     -I"$RUMPK_DIR/core/net" \
#     -I"$RUMPK_DIR/vendor/lwip/src/include" \
#     -c "$RUMPK_DIR/core/net/sys_arch.c" \
#     -o "$BUILD_DIR/sys_arch.o"
# 
# echo "      → LwIP objects compiled."

# =========================================================
# Step 3: Compile Nim L1 (Kernel + Fibers)
# =========================================================
echo "[3/8] Compiling Nim L1 (Kernel + Fibers)..."
mkdir -p "$BUILD_DIR/nimcache"
nim c \
    --cpu:$NIM_CPU \
    --os:any \
    --mm:arc \
    --noMain:on \
    --cc:clang \
    --passC:"-target ${ZIG_TARGET/-freestanding-none/-unknown-none} -ffreestanding -fno-stack-protector -fno-builtin $ARCH_FLAGS -I$RUMPK_DIR/core/include" \
    --define:useMalloc \
    --define:nimNoLibc \
    --define:noSignalHandler \
    --define:$NIM_DEFINE \
    -d:release \
    -d:danger \
    --nimcache:"$BUILD_DIR/nimcache" \
    --path:"$RUMPK_DIR/core" \
    -c \
    "$RUMPK_DIR/core/kernel.nim"

# =========================================================
# Step 4: Compile Nim C files
# =========================================================
echo "[4/8] Compiling Nim C files..."
zig cc \
    -target $ZIG_TARGET \
    $ARCH_FLAGS \
    -ffreestanding \
    -fno-stack-protector \
    -fno-builtin \
    -O2 \
    -I"$RUMPK_DIR/core/include" \
    -c "$RUMPK_DIR/core/cstubs.c" \
    -o "$BUILD_DIR/cstubs.o"
echo "      → $BUILD_DIR/cstubs.o"

NIM_OBJS=""
for cfile in "$BUILD_DIR/nimcache"/*.c; do
    ofile="${cfile%.c}.o"
    zig cc \
        -target $ZIG_TARGET \
        -ffreestanding \
        -fno-stack-protector \
        -fno-builtin \
        -fno-sanitize=all \
        $ARCH_FLAGS \
        -I"$RUMPK_DIR/core/include" \
        -I/usr/lib/nim \
        -I"$RUMPK_DIR/core" \
        -c "$cfile" \
        -o "$ofile"
    NIM_OBJS="$NIM_OBJS $ofile"
done
echo "      → $BUILD_DIR/nimcache/*.o"

# =========================================================
# Step 4.1: Compile Overrides (Math/Atomics Stubs)
# =========================================================
echo "[4.1/8] Compiling Sovereign Overrides..."
zig cc \
    -target $ZIG_TARGET \
    $ARCH_FLAGS \
    -ffreestanding \
    -fno-stack-protector \
    -fno-builtin \
    -O2 \
    -I"$RUMPK_DIR/core/include" \
    -c "$RUMPK_DIR/core/overrides.c" \
    -o "$BUILD_DIR/overrides.o"
echo "      → $BUILD_DIR/overrides.o"

# =========================================================
# Step 5: Compile Membrane Library (libnexus.a)
# =========================================================
echo "[5/8] Compiling Membrane Library (libnexus.a)..."
mkdir -p "$BUILD_DIR/membrane_nimcache"

# Compile clib.c (The Mini-Libc)
zig cc \
    -target $ZIG_TARGET \
    $ARCH_FLAGS \
    -ffreestanding \
    -fno-stack-protector \
    -fno-builtin \
    -O2 \
    -I"$RUMPK_DIR/core/include" \
    -c "$RUMPK_DIR/libs/membrane/clib.c" \
    -o "$BUILD_DIR/clib.o"

# Compile sys_arch.c (Membrane LwIP Platform Layer)
zig cc \
    -target $ZIG_TARGET \
    $ARCH_FLAGS \
    -ffreestanding \
    -fno-stack-protector \
    -fno-builtin \
    -O2 \
    -I"$RUMPK_DIR/core/include" \
    -I"$RUMPK_DIR/libs/membrane/include" \
    -I"$RUMPK_DIR/vendor/lwip/src/include" \
    -c "$RUMPK_DIR/libs/membrane/sys_arch.c" \
    -o "$BUILD_DIR/membrane_sys_arch.o"

nim c \
    --cpu:$NIM_CPU \
    --os:any \
    -d:is_membrane \
    -d:danger \
    -d:useMalloc \
    -d:nimNoLibc \
    -d:noSignalHandler \
    --gc:arc \
    --panics:on \
    --noMain \
    --hint:Conf:off \
    --hint:OSLib:off \
    --nimcache:"$BUILD_DIR/membrane_nimcache" \
    --path:"$RUMPK_DIR/libs/membrane" \
    --path:"$RUMPK_DIR/core" \
    -c \
    "$RUMPK_DIR/libs/membrane/libc.nim"

MEMBRANE_NIM_OBJS=""
for cfile in "$BUILD_DIR/membrane_nimcache"/*.c; do
    ofile="${cfile%.c}.o"
    zig cc \
        -target $ZIG_TARGET \
        -ffreestanding \
        -fno-stack-protector \
        -fno-builtin \
        -fno-sanitize=all \
        $ARCH_FLAGS \
        -I"$RUMPK_DIR/core/include" \
        -I/usr/lib/nim \
        -I"$RUMPK_DIR/core" \
        -I"$RUMPK_DIR/libs/membrane" \
        -I"$RUMPK_DIR/libs/membrane/include" \
        -I"$RUMPK_DIR/vendor/lwip/src/include" \
        -c "$cfile" \
        -o "$ofile"
    MEMBRANE_NIM_OBJS="$MEMBRANE_NIM_OBJS $ofile"
done

# =========================================================
# Step 5.1: Compile Subject Zig Object (Diamond Glass)
# =========================================================
echo "[5.1/8] Compiling Subject Zig Object..."

SUBJECT_SRC=${SUBJECT_SRC:-"$RUMPK_DIR/apps/subject_zig/main.zig"}

zig build-obj \
    -target $ZIG_TARGET \
    $ZIG_OBJ_FLAGS \
    -O ReleaseSmall \
    "$SUBJECT_SRC" \
    --name subject_zig

mv subject_zig.o "$BUILD_DIR/subject_zig.o"

# =========================================================
# Step 5.5: Patch Atomic References & Nuke Cache (GLOBAL)
# =========================================================
# We must do this BEFORE creating archives or linking anything.
# This ensures broken libcompiler_rt refs are removed from ALL objects.

echo "[5.5/8] Patching Atomic References & Nuking Cache..."

find "$BUILD_DIR" -name "*.o" | while read obj; do
    zig objcopy --redefine-syms="$RUMPK_DIR/core/re-symbol.txt" "$obj" "$obj" 2>/dev/null || true
    # Remove auto-linking sections
    zig objcopy \
        --remove-section .linker-options \
        --remove-section .comment \
        --remove-section .deplibs \
        --remove-section .llvm_addrsig \
        --remove-section .dependent-lib \
        "$obj" "$obj" 2>/dev/null || true
done

echo "      → SWAPPING libcompiler_rt.a with dummy archive (GLOB)..."
echo "" > "$BUILD_DIR/dummy.c"
zig cc -target $ZIG_TARGET -c "$BUILD_DIR/dummy.c" -o "$BUILD_DIR/dummy.o" $ARCH_FLAGS

for lib in "$BUILD_DIR"/.zig-cache/o/*/libcompiler_rt.a; do
    if [ -f "$lib" ]; then
        echo "        Replacing $lib"
        rm -f "$lib"
        zig ar rc "$lib" "$BUILD_DIR/dummy.o"
    fi
done

# =========================================================
# Step 5b: Create Membrane Archive
# =========================================================

# Note: We manually include ion_switch.o from the KERNEL nimcache if needed,
# but it should be in membrane_nimcache too because libc.nim imports it.
# Let's verify if ion_switch.o exists in membrane_nimcache.
ION_SWITCH_OBJ=$(ls "$BUILD_DIR/membrane_nimcache"/*ion_switch*o 2>/dev/null || echo "")

zig ar rc "$BUILD_DIR/libnexus.a" \
    $MEMBRANE_NIM_OBJS \
    $LWIP_MEMBRANE_OBJS \
    "$BUILD_DIR/clib.o" \
    "$BUILD_DIR/membrane_sys_arch.o" \
    "$BUILD_DIR/switch.o"

echo "      → $BUILD_DIR/libnexus.a"

# =========================================================
# Step 6: Link Subject Zero
# =========================================================
echo "[6/8] Linking Subject Zero (Canary)..."

# Note: subject_zero.o and libnexus.a are already compiled and patched.

# =========================================================
# Step 6: Link Subject Zig
# =========================================================
echo "[6/8] Linking Subject Zig..."

zig cc \
    -target $ZIG_TARGET \
    -nostdlib \
    -T "$RUMPK_DIR/apps/linker_user.ld" \
    "$BUILD_DIR/subject_zig.o" \
    "$BUILD_DIR/libnexus.a" \
    -o "$BUILD_DIR/subject.elf" \
    -lgcc

echo "      → $BUILD_DIR/subject.elf"
zig objcopy -O binary "$BUILD_DIR/subject.elf" "$BUILD_DIR/subject.bin"
echo "      → $BUILD_DIR/subject.bin"

# =========================================================
# Step 7: Compile Loader (After Subject)
# =========================================================
echo "[7/8] Compiling Loader (with Embedded Subject)..."

# Copy subject.bin to core/ so loader.zig can embed it (package path restriction)
cp "$BUILD_DIR/subject.bin" "$RUMPK_DIR/core/subject.bin"

zig build-obj \
    -target $ZIG_TARGET \
    $ZIG_OBJ_FLAGS \
    -O ReleaseFast \
    "$RUMPK_DIR/core/loader.zig" \
    --name loader
mv loader.o "$BUILD_DIR/loader.o"
echo "      → $BUILD_DIR/loader.o"

# Clean up temp file
rm "$RUMPK_DIR/core/subject.bin"

# Patch Loader Object specifically
echo "      → Patching Loader Object..."
obj="$BUILD_DIR/loader.o"
zig objcopy --redefine-syms="$RUMPK_DIR/core/re-symbol.txt" "$obj" "$obj" 2>/dev/null || true
zig objcopy \
    --remove-section .linker-options \
    --remove-section .comment \
    --remove-section .deplibs \
    --remove-section .llvm_addrsig \
    --remove-section .dependent-lib \
    "$obj" "$obj" 2>/dev/null || true

# =========================================================
# Step 8: Link Kernel (Direct LLD Bypass)
# =========================================================
echo "[8/8] Linking Kernel ($ARCH) using LLD..."

# Check if ld.lld is available, otherwise assume zig cc wrapper but we try direct first
LINKER="ld.lld"
EMULATION=""

if [ "$ARCH" = "riscv64" ]; then
    EMULATION="-m elf64lriscv"
elif [ "$ARCH" = "x86_64" ]; then
    EMULATION="-m elf_x86_64"
elif [ "$ARCH" = "aarch64" ]; then
    EMULATION="-m aarch64elf"
fi

$LINKER \
    -t \
    $EMULATION \
    --gc-sections \
    -T "$RUMPK_DIR/hal/arch/$ARCH/linker.ld" \
    "$BUILD_DIR/hal.o" \
    "$BUILD_DIR/stubs.o" \
    "$BUILD_DIR/channel.o" \
    "$BUILD_DIR/switch.o" \
    "$BUILD_DIR/monocypher.o" \
    "$BUILD_DIR/cstubs.o" \
    "$BUILD_DIR/overrides.o" \
    "$BUILD_DIR/loader.o" \
    "$BUILD_DIR/nexshell.o" \
    $NIM_OBJS \
    -o "$BUILD_DIR/rumpk-$ARCH.elf"

echo "      → $BUILD_DIR/rumpk-$ARCH.elf"

echo ""
echo "✅ Build complete for $ARCH!"
echo "Run with:"
echo "  qemu-system-riscv64 -M virt -nographic -kernel $BUILD_DIR/rumpk-riscv64.elf -netdev user,id=n0 -device virtio-net-pci,netdev=n0,disable-modern=on"
echo ""