#!/usr/bin/env bash
# scripts/quality/clang-format.sh
#
# Verify every source file under code/{include,src,tests} matches the
# project's `.clang-format` policy.  Runs in dry-run mode by default —
# only reports diffs; never edits files.
#
# Pass `--fix` to apply the suggested formatting in place.
#
# Local-only.  Promotion to CI is intended once the existing tree is
# 100 %-conformant; today we report drift but don't fail (the script
# exits non-zero only with `--strict`).
#
# Usage:
#   bash scripts/quality/clang-format.sh           # dry-run, exit 0 always
#   bash scripts/quality/clang-format.sh --strict  # dry-run, exit 1 on drift
#   bash scripts/quality/clang-format.sh --fix     # apply changes
#
# Exit codes:
#   0  no drift, or drift but --strict not set
#   1  drift detected AND --strict (or fixes applied AND --fix)
#   2  prerequisite missing

set -uo pipefail
ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
cd "$ROOT" || exit 2

command -v clang-format >/dev/null 2>&1 || {
    echo "FAIL: clang-format not in PATH." >&2
    echo "        macOS: brew install clang-format" >&2
    echo "        Linux: sudo apt install clang-format" >&2
    exit 2
}

STRICT=0
FIX=0
for arg in "$@"; do
    case "$arg" in
        --strict) STRICT=1 ;;
        --fix)    FIX=1 ;;
        *) echo "Unknown arg: $arg" >&2; exit 2 ;;
    esac
done

FILES_LIST="$(find code/include code/src code/tests \
    \( -name "*.h" -o -name "*.hpp" -o -name "*.cpp" \) \
    -type f 2>/dev/null \
    | grep -v "^code/deps/" \
    | grep -v " 2\." \
    | sort)"

n_total=0
n_drift=0
drift_list=""
while IFS= read -r f; do
    [ -z "$f" ] && continue
    n_total=$((n_total + 1))
    if [ "$FIX" -eq 1 ]; then
        clang-format -i "$f"
    else
        # --dry-run + -Werror sets non-zero exit when changes would be made.
        if ! clang-format --dry-run -Werror "$f" >/dev/null 2>&1; then
            n_drift=$((n_drift + 1))
            drift_list="$drift_list  $f
"
        fi
    fi
done <<EOF
$FILES_LIST
EOF

echo "clang-format ($(clang-format --version | head -1))"
echo "Scanned $n_total source files."

if [ "$FIX" -eq 1 ]; then
    echo "FIX mode: applied formatting in place."
    exit 0
fi

if [ "$n_drift" -gt 0 ]; then
    echo
    echo "DRIFT: $n_drift file(s) do not match .clang-format policy:"
    printf "%s" "$drift_list"
    echo
    echo "Recovery:"
    echo "  bash scripts/quality/clang-format.sh --fix   # apply"
    echo "  git diff                                     # review"
    if [ "$STRICT" -eq 1 ]; then
        exit 1
    fi
    echo "  (--strict not set → exiting 0 anyway)"
    exit 0
fi

echo "OK: every file matches .clang-format policy."
exit 0