#!/bin/bash
# ---------------------------------------------------------------------------
# Cross-build CPython 3.13 for the FlashForge Creator 5 Pro (Ingenic mipsel).
#
# THIS IS THE MEASUREMENT HARNESS, NOT THE BUILD. pkg/python is what produces
# the interpreter a package ships: it compiles inside the repo's own build
# image, from the tarballs pinned in versions.env, and caches the result in
# work/pkg/python. The two are the same build -- same flags,
# same wrappers, same gates -- but this one re-execs itself inside a
# throwaway debian:bookworm, which is how every number in README.md beside it
# was measured, and which is the fastest way to try a change to the recipe
# without touching the build lane. Exactly the relationship
# tools/supervisor/build.sh has to section 5b.
#
# Target ABI, measured, non-negotiable:
#   e_flags = 0x70001405  =  ELF32 / little-endian / NAN2008 / O32 /
#                            hard-float / mips32r2
#   loader  = /lib/ld-linux-mipsn8.so.1 , rootfs glibc 2.33
#
# Toolchain: the repo's Ingenic gcc 7.2 / glibc 2.29 cross compiler -- the SAME
# one bin/patch.sh uses for klippy's c_helper.so. musl is forbidden: a
# musl-linked interpreter cannot dlopen a glibc c_helper.so, which is exactly
# how klippy loads it. glibc 2.29 -> 2.33 is forward compatible.
#
# `-EL -mnan=2008` must reach BOTH the compile and the link of every object.
# Rather than trust each project's build system to forward CFLAGS to its link
# line (several do not), we install PATH wrappers that bake the two flags into
# the driver itself. That is the single most important trick in this file.
#
# Usage:
#     ./tools/python/build.sh                  # the whole thing, in docker
#     ./tools/python/build.sh --in-container   # the actual build
#
# Artifacts land in tools/python/out/ (gitignored, like everything else this
# repo builds): py313.tgz is the trimmed tree the payload would carry,
# py313-full.tgz is everything `make install` produced.
# ---------------------------------------------------------------------------
set -euo pipefail

HERE="$(cd "$(dirname "$0")" && pwd)"
REPO="${REPO:-$(cd "$HERE/../.." && pwd)}"
TOOLCHAIN_HOST="$REPO/work/.mips-toolchain/mips-gcc720-glibc229"

# --------------------------------------------------------------- versions ---
# Kept in step with versions.env by hand. They are duplicated rather than
# sourced because this script has to run against a source tree it is
# experimenting on -- bumping a version HERE first, seeing what breaks, and
# only then editing the pin -- which is the whole reason it still exists.
PY_VER="${PY_VER:-3.13.7}"
ZLIB_VER=1.3.1
OSSL_VER=3.0.15
FFI_VER=3.4.6
SQLITE_TAR=sqlite-autoconf-3460100      # 3.46.1
XZ_VER=5.4.7
BZIP2_VER=1.0.8
EXPAT_VER=2.6.4
EXPAT_TAG=R_2_6_4
# The mod's prefix root on the printer, and the same --prefix bin/patch.sh
# builds with: bin/python3.13 beside bin/s6-svscan, stdlib in
# lib/python3.13/. The one difference is that patch.sh deletes the `python3`
# symlink (and idle3/pydoc3/*-config) out of bin/ before staging, so that
# putting $MODDIR/bin on PATH cannot quietly change what `python3` means --
# see tools/python/README.md. This harness leaves the tree as `make install`
# produced it, because the sizes reported below are of that tree.
PREFIX=/usr/data/anvil

# ------------------------------------------------------- docker wrapper -----
if [ "${1:-}" != "--in-container" ]; then
    [ -x "$TOOLCHAIN_HOST/bin/mips-linux-gnu-gcc" ] || {
        echo "!! no toolchain at $TOOLCHAIN_HOST" >&2
        echo "   run ./bin/fetch-assets.sh, then any build (bin/patch.sh unpacks it)" >&2
        exit 1; }
    exec docker run --rm \
        -v "$TOOLCHAIN_HOST":/toolchain:ro \
        -v "$HERE":/work \
        -e PY_VER="$PY_VER" -e PY_EXTRA_CONFIGURE="${PY_EXTRA_CONFIGURE:-}" \
        -e HOST_UID="$(id -u)" -e HOST_GID="$(id -g)" \
        -w /work debian:bookworm \
        bash /work/build.sh --in-container
fi

# =========================== everything below runs inside the container ======
START=$(date +%s)
export DEBIAN_FRONTEND=noninteractive
TC=/toolchain
W=/work
SRC=$W/src            # tarball cache (survives between runs)
B=$W/build            # scratch: unpacked trees
HOSTPY=$W/hostpy      # the x86-64 build-Python 3.13 (--with-build-python)
DEP=$W/deproot        # cross-built C libraries, STATIC.  Not shipped.
STAGE=$W/stage        # DESTDIR: what actually goes on the printer
OUT=$W/out
mkdir -p "$SRC" "$B" "$HOSTPY" "$DEP" "$OUT"

log() { echo; echo "===== $* ====="; }

log "apt: build dependencies"
apt-get update -qq
apt-get install -y -qq --no-install-recommends \
    build-essential curl ca-certificates pkg-config perl file xz-utils \
    zlib1g-dev libssl-dev libffi-dev >/dev/null

# ------------------------------------------------------- the wrappers -------
# -EL -mnan=2008 on every invocation, compile or link.  Without -mnan=2008 the
# objects are legacy-NaN and the kernel refuses to load the result.
log "toolchain wrappers (-EL -mnan=2008 baked in)"
mkdir -p /opt/xw/bin
for t in gcc g++ cpp; do
    cat > /opt/xw/bin/mips-linux-gnu-$t <<EOF
#!/bin/sh
exec $TC/bin/mips-linux-gnu-$t -EL -mnan=2008 "\$@"
EOF
    chmod +x /opt/xw/bin/mips-linux-gnu-$t
done
for t in ar as ld nm objcopy objdump ranlib readelf strip strings size; do
    ln -sf $TC/bin/mips-linux-gnu-$t /opt/xw/bin/mips-linux-gnu-$t
done
export PATH=/opt/xw/bin:$PATH
mips-linux-gnu-gcc --version | head -1

# gate the wrapper itself before building 300MB on top of it
echo 'int main(void){return 0;}' > /tmp/abi.c
mips-linux-gnu-gcc /tmp/abi.c -o /tmp/abi.out
FLAGS=$(mips-linux-gnu-readelf -h /tmp/abi.out | awk '/Flags:/{print $2}' | tr -d ,)
echo "wrapper produces e_flags=$FLAGS"
[ "$FLAGS" = "0x70001405" ] || { echo "!! wrong ABI from the wrapper"; exit 1; }

# ------------------------------------------------------------ fetch ---------
# No sha256 here on purpose: versions.env holds the pins and
# bin/fetch-assets.sh is what enforces them for anything that ships. This
# harness downloads whatever version you point it at, which is what makes it
# useful for deciding whether a bump is safe BEFORE it becomes a pin.
fetch() {  # fetch <url>  -> $SRC/<basename>, cached
    local url=$1 f="$SRC/$(basename "$1")"
    [ -s "$f" ] || { echo ">> $url"; curl -sSLf -o "$f.part" "$url" && mv "$f.part" "$f"; }
}
log "fetch sources"
fetch https://www.python.org/ftp/python/$PY_VER/Python-$PY_VER.tgz
fetch https://zlib.net/fossils/zlib-$ZLIB_VER.tar.gz
fetch https://github.com/openssl/openssl/releases/download/openssl-$OSSL_VER/openssl-$OSSL_VER.tar.gz
fetch https://github.com/libffi/libffi/releases/download/v$FFI_VER/libffi-$FFI_VER.tar.gz
fetch https://www.sqlite.org/2024/$SQLITE_TAR.tar.gz
fetch https://github.com/tukaani-project/xz/releases/download/v$XZ_VER/xz-$XZ_VER.tar.gz
fetch https://sourceware.org/pub/bzip2/bzip2-$BZIP2_VER.tar.gz
fetch https://github.com/libexpat/libexpat/releases/download/$EXPAT_TAG/expat-$EXPAT_VER.tar.gz

unpack() { rm -rf "$B/${2}"; tar -xf "$SRC/$1" -C "$B"; }

# ============================================ 1. host CPython 3.13 ==========
# Cross-building CPython needs a build-Python of the *same* version: the
# Makefile runs it to freeze modules, generate deepfreeze sources and byte
# compile the stdlib.  A distro python3.11 will not do.
if [ ! -x "$HOSTPY/bin/python3.13" ]; then
    log "host CPython $PY_VER (x86-64, for --with-build-python)"
    unpack Python-$PY_VER.tgz Python-$PY_VER
    cd "$B/Python-$PY_VER"
    ./configure --prefix="$HOSTPY" --without-ensurepip >/dev/null
    make -j"$(nproc)" >/dev/null
    make install >/dev/null
    cd /
else
    log "host CPython already built -- reusing $HOSTPY"
fi
"$HOSTPY/bin/python3.13" -VV

# ============================================ 2. cross C libraries ==========
# All STATIC (-fPIC) into $DEP.  Rationale: linking them into the interpreter
# and its extension modules means the shipped tree has no .so of ours to find
# at runtime, so there is no LD_LIBRARY_PATH for dependencies, no chance of
# picking up FlashForge's /usr/prog copies, and nothing to version-skew.  The
# only cost is a few MB of duplicated libcrypto between _ssl.so and _hashlib.so.
export CC=mips-linux-gnu-gcc
export CXX=mips-linux-gnu-g++
export AR=mips-linux-gnu-ar
export RANLIB=mips-linux-gnu-ranlib
export STRIP=mips-linux-gnu-strip
export CFLAGS="-O2 -fPIC -D_FILE_OFFSET_BITS=64"
export CPPFLAGS="-I$DEP/include"
export LDFLAGS="-L$DEP/lib"
# pkg-config must see ONLY our sysroot, never the container's /usr/lib.
export PKG_CONFIG_LIBDIR="$DEP/lib/pkgconfig"
export PKG_CONFIG_PATH="$DEP/lib/pkgconfig"
HOSTTRIPLE=mips-linux-gnu
BUILDTRIPLE=x86_64-linux-gnu

log "zlib $ZLIB_VER"
unpack zlib-$ZLIB_VER.tar.gz zlib-$ZLIB_VER
cd "$B/zlib-$ZLIB_VER"
CHOST=$HOSTTRIPLE ./configure --prefix="$DEP" --static >/dev/null
make -j"$(nproc)" >/dev/null && make install >/dev/null

log "openssl $OSSL_VER"
unpack openssl-$OSSL_VER.tar.gz openssl-$OSSL_VER
cd "$B/openssl-$OSSL_VER"
# linux-mips32 is the O32 target.  openssldir points at where the interpreter
# will look for certs ON THE PRINTER, not at a build path.
#
# Two traps, both hit for real:
#  * `no-docs` only exists from OpenSSL 3.1.  On 3.0.15 it is an "Unsupported
#    options" hard error, not a warning.
#  * the linux-mips32 target hardcodes `-mips2` into its cflags.  This
#    toolchain defaults to -mfp64 (hard-float, fp64 registers), and gcc
#    rejects `-mgp32 -mfp64` on anything below mips32r2:
#       error: '-mgp32' and '-mfp64' can only be combined if the target
#              supports the mfhc1 and mthc1 instructions
#    User cflags land AFTER the target's on the command line, so appending
#    -mips32r2 puts the ISA back where the printer actually is.  If a future
#    OpenSSL orders them the other way, linux-generic32 (portable C, no mips
#    assembly) is the fallback and is exercised below.
OSSL_TARGET=linux-mips32
OSSL_ISA=-mips32r2
./Configure $OSSL_TARGET \
    --prefix="$DEP" --libdir=lib --openssldir=$PREFIX/ssl \
    no-shared no-tests \
    -fPIC -O2 $OSSL_ISA -D_FILE_OFFSET_BITS=64 >/dev/null
if ! make -j"$(nproc)" >"$OUT/openssl.log" 2>&1; then
    echo "!! $OSSL_TARGET failed; falling back to linux-generic32 (no mips asm)"
    tail -20 "$OUT/openssl.log"
    make distclean >/dev/null 2>&1 || true
    ./Configure linux-generic32 \
        --prefix="$DEP" --libdir=lib --openssldir=$PREFIX/ssl \
        no-shared no-tests no-asm \
        -fPIC -O2 -D_FILE_OFFSET_BITS=64 >/dev/null
    make -j"$(nproc)" >"$OUT/openssl.log" 2>&1
fi
make install_sw >/dev/null

log "libffi $FFI_VER"
unpack libffi-$FFI_VER.tar.gz libffi-$FFI_VER
cd "$B/libffi-$FFI_VER"
./configure --host=$HOSTTRIPLE --build=$BUILDTRIPLE --prefix="$DEP" \
    --disable-shared --enable-static --with-pic --disable-docs >/dev/null
make -j"$(nproc)" >/dev/null && make install >/dev/null

log "sqlite ($SQLITE_TAR) -- THE reason this whole exercise exists"
unpack $SQLITE_TAR.tar.gz $SQLITE_TAR
cd "$B/$SQLITE_TAR"
./configure --host=$HOSTTRIPLE --build=$BUILDTRIPLE --prefix="$DEP" \
    --disable-shared --enable-static --with-pic \
    --disable-readline --disable-editline >/dev/null
make -j"$(nproc)" >/dev/null && make install >/dev/null

log "xz (liblzma) $XZ_VER"
unpack xz-$XZ_VER.tar.gz xz-$XZ_VER
cd "$B/xz-$XZ_VER"
./configure --host=$HOSTTRIPLE --build=$BUILDTRIPLE --prefix="$DEP" \
    --disable-shared --enable-static --with-pic \
    --disable-xz --disable-xzdec --disable-lzmadec --disable-lzmainfo \
    --disable-scripts --disable-doc --disable-nls >/dev/null
make -j"$(nproc)" >/dev/null && make install >/dev/null

log "bzip2 $BZIP2_VER"
unpack bzip2-$BZIP2_VER.tar.gz bzip2-$BZIP2_VER
cd "$B/bzip2-$BZIP2_VER"
# bzip2 has no configure; drive its Makefile directly.
make -j"$(nproc)" libbz2.a CC="$CC" AR="$AR" RANLIB="$RANLIB" \
    CFLAGS="-O2 -fPIC -D_FILE_OFFSET_BITS=64 -Wall -Winline" >/dev/null
install -m644 libbz2.a "$DEP/lib/"
install -m644 bzlib.h  "$DEP/include/"

log "expat $EXPAT_VER"
unpack expat-$EXPAT_VER.tar.gz expat-$EXPAT_VER
cd "$B/expat-$EXPAT_VER"
./configure --host=$HOSTTRIPLE --build=$BUILDTRIPLE --prefix="$DEP" \
    --disable-shared --enable-static --with-pic \
    --without-docbook --without-examples --without-tests >/dev/null
make -j"$(nproc)" >/dev/null && make install >/dev/null

echo "-- $DEP/lib --"; ls "$DEP/lib"

# ============================================ 3. CPython, cross =============
log "CPython $PY_VER cross for $HOSTTRIPLE"
unpack Python-$PY_VER.tgz Python-$PY_VER
cd "$B/Python-$PY_VER"

# Answers configure cannot probe because it may not run target binaries.
cat > "$B/config.site" <<'EOF'
ac_cv_file__dev_ptmx=yes
ac_cv_file__dev_ptc=no
ac_cv_buggy_getaddrinfo=no
ac_cv_little_endian_double=yes
ac_cv_big_endian_double=no
ac_cv_mixed_endian_double=no
ac_cv_working_tzset=yes
ac_cv_have_long_long_format=yes
ac_cv_no_strict_aliasing=no
ac_cv_pthread_system_supported=yes
EOF

export CONFIG_SITE="$B/config.site"
export CPPFLAGS="-I$DEP/include"
export LDFLAGS="-L$DEP/lib"
# -latomic: 64-bit atomics on mips32 are out-of-line calls into libatomic, and
#   CPython 3.13's _Py_atomic_* on 64-bit types needs them.
# -lm: because the sqlite/lzma/expat libraries here are STATIC.  A shared
#   libsqlite3.so carries its own DT_NEEDED on libm; a libsqlite3.a does not,
#   so configure's `checking for sqlite3_bind_double in -lsqlite3` link probe
#   fails with a wall of `undefined reference to floor/log/pow/...` and 3.13
#   silently records _sqlite3 as "missing" -- which is the one module this
#   whole build exists for.  It is a probe failure, not a compile failure, so
#   nothing in the build output says why.
export LIBS="-latomic -lm"
export CFLAGS="-O2 -D_FILE_OFFSET_BITS=64"
# Bypass pkg-config for sqlite and state the static link line outright, so the
# -lm above cannot be reordered out from under the probe.
export LIBSQLITE3_CFLAGS="-I$DEP/include"
export LIBSQLITE3_LIBS="-L$DEP/lib -lsqlite3 -lm"

./configure \
    --host=$HOSTTRIPLE --build=$BUILDTRIPLE \
    --with-build-python="$HOSTPY/bin/python3.13" \
    --prefix=$PREFIX \
    --disable-shared \
    --without-ensurepip \
    --disable-test-modules \
    --with-openssl="$DEP" \
    --with-system-expat \
    ${PY_EXTRA_CONFIGURE:-} 2>&1 | tee "$OUT/configure.log" | tail -60

echo "-- configure: modules it decided it could not build --"
grep -iE 'could not be built|missing|failed to build' -A6 "$OUT/configure.log" | tail -40 || true

make -j"$(nproc)" 2>&1 | tee "$OUT/make.log" | tail -40
echo "-- build: modules that failed --"
grep -iE 'necessary bits|could not be found|failed to build these' -A10 "$OUT/make.log" | tail -40 || true

rm -rf "$STAGE"
make install DESTDIR="$STAGE" 2>&1 | tail -20

# ============================================ 4. gates + package ============
log "ABI gate on every ELF in the stage"
# The measured target word is 0x70001405 for an EXECUTABLE.  Shared objects
# additionally carry EF_MIPS_PIC (0x2) and so read 0x70001407 -- that is
# correct and unavoidable for a DYN, and klippy's own c_helper.so has it too.
# So gate on the ABI ATTRIBUTES, which is also what bin/patch.sh does
# (`readelf -h | grep -q nan2008`), and pin the whole word per ELF type.
BAD=0; N=0
while IFS= read -r f; do
    case "$(file -b "$f")" in *ELF*) ;; *) continue;; esac
    hdr=$(mips-linux-gnu-readelf -h "$f" 2>/dev/null)
    fl=$(echo "$hdr" | awk '/Flags:/{print $2}' | tr -d ,)
    typ=$(echo "$hdr" | awk '/^  Type:/{print $2}')
    want=0x70001405; [ "$typ" = "DYN" ] && want=0x70001407
    case "$hdr" in
        *nan2008*o32*mips32r2*) ;;
        *) echo "!! $f  not nan2008/o32/mips32r2"; BAD=1; continue;;
    esac
    if [ "$fl" != "$want" ]; then
        echo "!! $f  type=$typ flags=$fl want=$want"; BAD=1
    fi
    N=$((N+1))
done < <(find "$STAGE" -type f)
[ $BAD -eq 0 ] && echo "$N ELF objects, all nan2008/o32/mips32r2 (EXEC 0x70001405, DYN 0x70001407)" || exit 1

# _sqlite3 is the reason this build exists.  Its absence must be a hard error,
# not a line in a 400-line make log that nobody reads.
if ! ls "$STAGE$PREFIX/lib/python3.13/lib-dynload/"_sqlite3*.so >/dev/null 2>&1; then
    echo "!! NO _sqlite3 MODULE WAS BUILT -- see $OUT/configure.log and config.log"
    exit 1
fi
echo "_sqlite3 present: $(basename "$(ls "$STAGE$PREFIX/lib/python3.13/lib-dynload/"_sqlite3*.so)")"

echo "-- NEEDED of the interpreter --"
mips-linux-gnu-readelf -d "$STAGE$PREFIX/bin/python3.13" | grep -E 'NEEDED|RPATH|RUNPATH' || true
echo "-- lib-dynload --"
ls "$STAGE$PREFIX/lib/python3.13/lib-dynload/" | sed 's/\.cpython.*//' | sort | tr '\n' ' '; echo

log "sizes"
FULL=$(du -sm "$STAGE" | cut -f1)
# trimmed: what would actually ship
rm -rf "$W/stage-trim"
cp -a "$STAGE" "$W/stage-trim"
rm -rf "$W/stage-trim$PREFIX/lib/python3.13/test" \
       "$W/stage-trim$PREFIX/lib/python3.13/idlelib" \
       "$W/stage-trim$PREFIX/lib/python3.13/tkinter" \
       "$W/stage-trim$PREFIX/lib/python3.13/turtledemo" \
       "$W/stage-trim$PREFIX/lib/python3.13/config-"* \
       "$W/stage-trim$PREFIX/include" \
       "$W/stage-trim$PREFIX/share"
find "$W/stage-trim" -name '__pycache__' -prune -exec rm -rf {} + 2>/dev/null || true
find "$W/stage-trim" -name '*.a' -delete
mips-linux-gnu-strip "$W/stage-trim$PREFIX/bin/python3.13" 2>/dev/null || true
find "$W/stage-trim$PREFIX/lib/python3.13/lib-dynload" -name '*.so' \
    -exec mips-linux-gnu-strip {} + 2>/dev/null || true
TRIM=$(du -sm "$W/stage-trim" | cut -f1)
echo "staged  : ${FULL} MB, $(find "$STAGE" -type f | wc -l) files"
echo "trimmed : ${TRIM} MB, $(find "$W/stage-trim" -type f | wc -l) files"

log "tarballs"
# The tarball's root is 'usr/data/anvil/...' relative -- unpack with -C /
( cd "$STAGE" && tar -czf "$OUT/py313-full.tgz" usr )
( cd "$W/stage-trim" && tar -czf "$OUT/py313.tgz" usr )
ls -l "$OUT"/*.tgz
chown -R "${HOST_UID:-0}:${HOST_GID:-0}" "$W" 2>/dev/null || true

END=$(date +%s)
log "done in $(( (END-START)/60 ))m $(( (END-START)%60 ))s"