#!/usr/bin/env bash
#
# Minimal reproducible MSVC 6.0 compile probe for the Windows 9x port.
#
# Runs the external MSVC600 `cl.exe` under Wine against the CPython 3.11.16
# baseline in ./cpython, using the project-local compatibility headers in
# ./compat/msvc600.  Compile-only (/c): this probe measures how far the VC6
# front end gets through the public headers, it does not attempt to link.
#
# The MSVC600 bundle is an external, local-only prerequisite; nothing under
# MSVC600/ is part of this project's source.
#
# Usage:
#   scripts/vc6-probe.sh                    # probe Programs/python.c
#   scripts/vc6-probe.sh path/to/other.c    # probe another translation unit
#
# Environment:
#   MSVC600_ROOT  override the MSVC600 location (default: <repo>/MSVC600)
#   WINEPREFIX    override the Wine prefix (default: ~/.wine-win9xport)

set -u

# Absolute POSIX path -> Wine drive Z: path.
winpath() { printf 'Z:%s' "${1//\//\\}"; }

# Strip a literal (non-regex) prefix from every line of stdin.
#
# sed and bash glob patterns both treat backslashes in the *pattern* as
# escape characters, so passing a Windows path (full of literal `\`
# separators) as a sed/glob pattern silently fails to match: `\h`, `\u`,
# etc. are consumed as (mostly no-op) escapes instead of literal
# characters. Quoting the parameter inside a bash `${var//pattern/}`
# expansion forces literal (non-glob) matching, which sidesteps the
# problem entirely.
strip_prefix() {
    local prefix="$1" line
    while IFS= read -r line || [ -n "$line" ]; do
        printf '%s\n' "${line//"$prefix"/}"
    done
}

run_probe() {
    REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
    MSVC600_ROOT="${MSVC600_ROOT:-$REPO_ROOT/MSVC600}"
    BUILD_DIR="$REPO_ROOT/build/vc6-probe"

    SOURCE_REL="${1:-cpython/Programs/python.c}"
    SOURCE_ABS="$REPO_ROOT/$SOURCE_REL"

    CL="$MSVC600_ROOT/VC98/Bin/CL.EXE"
    VCVARS="$MSVC600_ROOT/VC98/Bin/VCVARS32.BAT"

    for required in "$CL" "$VCVARS" "$MSVC600_ROOT/VC98/Include" \
                    "$MSVC600_ROOT/Common/MSDev98/Bin" "$SOURCE_ABS"; do
        if [ ! -e "$required" ]; then
            echo "vc6-probe: missing prerequisite: $required" >&2
            return 2
        fi
    done

    if ! command -v wine >/dev/null 2>&1; then
        echo "vc6-probe: wine is not installed" >&2
        return 2
    fi

    export WINEPREFIX="${WINEPREFIX:-$HOME/.wine-win9xport}"
    export WINEDEBUG="${WINEDEBUG:--all}"

    # CL.EXE loads C1/C2 from VC98/Bin and MSPDB60.DLL from Common/MSDev98/Bin.
    export WINEPATH="$(winpath "$MSVC600_ROOT/VC98/Bin");$(winpath "$MSVC600_ROOT/Common/MSDev98/Bin")"

    mkdir -p "$BUILD_DIR"

    INCLUDE_ARGS=(
        "$(winpath "$REPO_ROOT/compat/msvc600")"
        "$(winpath "$REPO_ROOT/cpython/Include")"
        "$(winpath "$REPO_ROOT/cpython/PC")"
        "$(winpath "$MSVC600_ROOT/VC98/Include")"
    )

    echo "== MSVC600 compile probe =="
    echo "source : $SOURCE_REL"
    echo "prefix : $WINEPREFIX"
    echo

    CMD="call $(winpath "$VCVARS") && cd /d $(winpath "$REPO_ROOT/cpython") && cl /nologo"
    for include_arg in "${INCLUDE_ARGS[@]}"; do
        CMD+=" /I $include_arg"
    done
    CMD+=" /c $(winpath "$SOURCE_ABS") /Fo$(winpath "$BUILD_DIR")\\"

    wine cmd /c "$CMD" 2>&1 |
        grep -v '^[0-9a-f]\{4\}:err:' |
        strip_prefix "$(winpath "$REPO_ROOT")\\"

    status="${PIPESTATUS[0]}"
    echo
    echo "== cl.exe exit status: $status =="
    return "$status"
}

# Allow `source scripts/vc6-probe.sh` (e.g. from tests) to pull in
# winpath/strip_prefix without running the probe itself.
if [ "${BASH_SOURCE[0]}" = "${0}" ]; then
    run_probe "$@"
    exit "$?"
fi