#!/usr/bin/env bash
# Remove generated build output from this checkout.
#
# Targets are limited to directories this project generates. Nothing tracked by
# git is removed, and Source/, third_party/, .git and the other project
# directories are refused even if they are named as a target.
set -euo pipefail

REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
cd "$REPO_ROOT"

usage() {
    cat <<'EOF'
Usage: scripts/clean.sh [options]

Removes generated build output. With no options it removes the build trees
under build/.

Options:
  --staging   also remove the staged Windows bundle, SerumAlt_Windows/
  --legacy    also remove build trees left in the repository root by earlier
              versions of the build scripts (build_*, cmake-build-*)
  --all       --staging and --legacy together
  --dry-run   print every path and its size, and remove nothing
  -h, --help  print this text
EOF
}

DRY_RUN=false
STAGING=false
LEGACY=false
for arg in "$@"; do
    case "$arg" in
        --dry-run) DRY_RUN=true ;;
        --staging) STAGING=true ;;
        --legacy) LEGACY=true ;;
        --all) STAGING=true; LEGACY=true ;;
        -h|--help) usage; exit 0 ;;
        *) echo "ERROR: unknown option: $arg" >&2; usage >&2; exit 2 ;;
    esac
done

if ! command -v git >/dev/null 2>&1; then
    echo "ERROR: git is required to confirm that no tracked file is removed." >&2
    exit 2
fi

# A build directory outside the repository belongs to some other checkout, and
# this script has no business deciding whether it is disposable.
for var in BUILD_DIR OUTPUT_DIR; do
    value="${!var:-}"
    [ -n "$value" ] || continue
    case "$value" in
        /*) abs="$value" ;;
        *) abs="$REPO_ROOT/$value" ;;
    esac
    abs="$(realpath -m -- "$abs" 2>/dev/null || printf '%s' "$abs")"
    case "$abs" in
        "$REPO_ROOT"/*) ;;
        *)
            echo "ERROR: $var=$value resolves outside $REPO_ROOT." >&2
            echo "       Unset $var to clean this repository." >&2
            exit 2
            ;;
    esac
done

PROTECTED=(Source third_party .git scripts cmake docs graft)

refused=0
removed=0

remove_target() {
    local path="$1"
    [ -e "$path" ] || return 0

    local abs rel size
    abs="$(realpath -m -- "$path")"
    rel="${abs#"$REPO_ROOT"/}"

    case "$abs" in
        "$REPO_ROOT"/*) ;;
        *)
            echo "refusing, outside the repository: $abs" >&2
            refused=$((refused + 1))
            return 1
            ;;
    esac

    local deny
    for deny in "${PROTECTED[@]}"; do
        if [ "$rel" = "$deny" ] || [ "${rel#"$deny"/}" != "$rel" ]; then
            echo "refusing, protected path: $rel" >&2
            refused=$((refused + 1))
            return 1
        fi
    done

    if [ -n "$(git ls-files -- "$rel")" ]; then
        echo "refusing, tracked by git: $rel" >&2
        refused=$((refused + 1))
        return 1
    fi

    size="$(du -sh -- "$rel" 2>/dev/null | cut -f1)"
    if [ "$DRY_RUN" = true ]; then
        printf 'would remove  %6s  %s\n' "${size:-?}" "$rel"
    else
        rm -rf -- "$abs"
        printf 'removed       %6s  %s\n' "${size:-?}" "$rel"
    fi
    removed=$((removed + 1))
}

TARGETS=("$REPO_ROOT/build")
if [ "$STAGING" = true ]; then
    TARGETS+=("$REPO_ROOT/SerumAlt_Windows")
fi
if [ "$LEGACY" = true ]; then
    shopt -s nullglob
    for dir in "$REPO_ROOT"/build_* "$REPO_ROOT"/cmake-build-*; do
        TARGETS+=("$dir")
    done
    shopt -u nullglob
fi

for target in "${TARGETS[@]}"; do
    remove_target "$target" || true
done

if [ "$removed" -eq 0 ] && [ "$refused" -eq 0 ]; then
    echo "Nothing to remove."
elif [ "$DRY_RUN" = true ]; then
    echo "Dry run: $removed path(s) listed, nothing removed."
fi

[ "$refused" -eq 0 ]