#!/usr/bin/env bash
# validate-patches.sh — Check that all recipe patches apply cleanly.
#
# Usage: ./local/scripts/validate-patches.sh [--rebase] [recipe...]
#
#   Without arguments, validates all recipes with patches.
#   With --rebase, runs patch --dry-run -R to check if the patch can
#     be reverse-applied (meaning it IS currently applied).
#   With recipe names/paths, validates only those recipes.
#
# Exit code: number of failed patches (0 = all clean).

set -euo pipefail

ROOT="$(cd "$(dirname "$0")/../.." && pwd)"
cd "$ROOT"

MODE="apply"   # apply | rebase
FAILED=0
CHECKED=0
TOTAL_PATCHES=0

red()  { printf "\033[1;31m%s\033[0m\n" "$*"; }
green(){ printf "\033[1;32m%s\033[0m\n" "$*"; }
cyan() { printf "\033[1;36m%s\033[0m\n" "$*"; }

while [[ $# -gt 0 ]]; do
    case "$1" in
        --rebase) MODE="rebase"; shift ;;
        *) break ;;
    esac
done

RECIPE_DIRS=("$@")
if [ ${#RECIPE_DIRS[@]} -eq 0 ]; then
    mapfile -t RECIPE_DIRS < <(find recipes -name "recipe.toml" -exec dirname {} \; | sort)
fi

validate_patch() {
    local recipe_dir="$1"
    local patch_name="$2"
    local patch_file="$3"
    local source_dir="$4"

    local flags="--strip=1 --batch --fuzz=0"
    if [ "$MODE" = "rebase" ]; then
        # Check if patch can be reverse-applied (it IS currently applied)
        if patch --dry-run --directory "$source_dir" $flags -R < "$patch_file" >/dev/null 2>&1; then
            return 0  # already applied → OK
        else
            echo "  $(red NEEDS REBASE) $patch_name"
            FAILED=$((FAILED + 1))
            return 1
        fi
    fi

    # Forward-apply check
    if patch --dry-run --directory "$source_dir" $flags < "$patch_file" >/dev/null 2>&1; then
        return 0
    fi

    # Show the actual error for diagnosis
    echo "  $(red FAILED) $patch_name"
    patch --dry-run --directory "$source_dir" $flags < "$patch_file" 2>&1 | head -5 | sed 's/^/    /'
    FAILED=$((FAILED + 1))
    return 1
}

for recipe_dir in "${RECIPE_DIRS[@]}"; do
    recipe_toml="$recipe_dir/recipe.toml"
    [ -f "$recipe_toml" ] || continue

    # Extract patch list from recipe.toml
    patches=$(grep -o '"[^"]*\.patch"' "$recipe_toml" 2>/dev/null | tr -d '"')

    [ -n "$patches" ] || continue

    source_dir="$recipe_dir/source"
    if [ ! -d "$source_dir" ]; then
        echo "$(cyan SKIP) $recipe_dir — no source directory"
        continue
    fi

    recipe_failed=0
    recipe_checked=0

    for patch_name in $patches; do
        # Resolve patch file path (handle relative paths like ../../../local/patches/...)
        patch_file="$recipe_dir/$patch_name"
        if [ ! -f "$patch_file" ]; then
            echo "  $(red MISSING) $patch_name ($patch_file)"
            FAILED=$((FAILED + 1))
            continue
        fi

        recipe_checked=$((recipe_checked + 1))
        TOTAL_PATCHES=$((TOTAL_PATCHES + 1))

        validate_patch "$recipe_dir" "$patch_name" "$patch_file" "$source_dir" || true
    done

    if [ "$recipe_checked" -gt 0 ]; then
        CHECKED=$((CHECKED + 1))
        if [ "$recipe_failed" -eq 0 ]; then
            echo "$(green OK) $recipe_dir — $recipe_checked patch(es) clean"
        fi
    fi
done

echo ""
echo "──────────────────────────────────────────"
echo "  Recipes checked: $CHECKED"
echo "  Total patches:   $TOTAL_PATCHES"
echo "  Failed:          $FAILED"
echo "──────────────────────────────────────────"

if [ "$FAILED" -eq 0 ]; then
    echo "$(green All patches apply cleanly)"
else
    red "$FAILED patch(es) need rebasing or fixing"
fi

exit $FAILED