#!/bin/bash
# verify-absorbed-patches.sh — verify which local/patches/relibc/absorbed/ patches
# have their changes present in local/sources/relibc source.
#
# Strategy: hardlink-copy relibc source into tmp, then test each patch.
# Use hardlinks so the relibc working tree is not mutated and the copy
# is fast (no full 4.5G copy).

set -euo pipefail

ROOT="$(cd "$(dirname "$0")/../.." && pwd)"
ABSORBED_DIR="$ROOT/local/patches/relibc/absorbed"
RELIBC_DIR="$ROOT/local/sources/relibc"

if [ ! -d "$ABSORBED_DIR" ]; then
    echo "ERROR: $ABSORBED_DIR not found"; exit 1
fi
if [ ! -d "$RELIBC_DIR" ]; then
    echo "ERROR: $RELIBC_DIR not found"; exit 1
fi

TMPDIR="$(mktemp -d -t rb-absorbed-check.XXXXXX)"
mkdir -p "$TMPDIR/src"

# Hardlink-copy with .git excluded (avoid cross-device hardlink failures)
rsync -a --exclude='.git' "$RELIBC_DIR"/ "$TMPDIR/src/"
cd "$TMPDIR/src"

OK_COUNT=0
GONE_COUNT=0
FAIL_COUNT=0
declare -a GONE_PATCHES=()
declare -a FAIL_PATCHES=()

for patch in "$ABSORBED_DIR"/*.patch; do
    [ -e "$patch" ] || continue
    name="$(basename "$patch")"

    # Try dry-run apply first (-N = no backup, --dry-run = test only).
    if patch --dry-run -p1 -N -i "$patch" >/dev/null 2>&1; then
        # Forward applies. Now test reverse — if reverse applies, the
        # content is currently present (STILL-EFFECTIVE); if reverse fails,
        # the content was merged upstream (MERGED-UPSTREAM).
        if patch --dry-run -p1 -R -N -i "$patch" >/dev/null 2>&1; then
            OK_COUNT=$((OK_COUNT+1)); status="STILL-EFFECTIVE"
        else
            OK_COUNT=$((OK_COUNT+1)); status="MERGED-UPSTREAM"
        fi
        # Restore source by removing the forward-applied hunks via reverse.
        patch -p1 -R -N -i "$patch" >/dev/null 2>&1 || true
    else
        # Forward dry-run fails. Test real apply; if successful, the content
        # was missing and the patch is now applied.
        if patch -p1 -N -i "$patch" >/dev/null 2>&1; then
            GONE_COUNT=$((GONE_COUNT+1)); status="APPLIED-NEW"
            GONE_PATCHES+=("$name")
            # Restore source for next patch.
            patch -p1 -R -N -i "$patch" >/dev/null 2>&1 || true
        else
            FAIL_COUNT=$((FAIL_COUNT+1)); status="BROKEN"
            FAIL_PATCHES+=("$name")
        fi
    fi

    printf '%-45s %s\n' "$name" "$status"
done

echo ""
echo "=========================================="
echo " ABSORBED-PATCH AUDIT SUMMARY"
echo "=========================================="
echo "Effective or merged: $OK_COUNT"
echo "APPLIED-NEW  (was missing): $GONE_COUNT"
echo "Broken (cannot apply): $FAIL_COUNT"
echo ""

if [ ${#GONE_PATCHES[@]} -gt 0 ]; then
    echo "Patches now applicable (likely needed):"
    for p in "${GONE_PATCHES[@]}"; do echo "  - $p"; done
    echo ""
fi

if [ ${#FAIL_PATCHES[@]} -gt 0 ]; then
    echo "Broken patches:"
    for p in "${FAIL_PATCHES[@]}"; do echo "  - $p"; done
    echo ""
fi

rm -rf "$TMPDIR"

if [ $FAIL_COUNT -gt 0 ]; then
    exit 1
fi
exit 0