#!/usr/bin/env bash
#
# pre-commit — format and lint staged Swift files before commit.
# Refreshes the index only for fully staged files; partially staged files must be re-staged manually.

set -euo pipefail

ROOT_DIR="$(git rev-parse --show-toplevel 2>/dev/null || true)"
if [[ -z "${ROOT_DIR}" ]]; then
    echo "pre-commit: could not determine git repository root."
    exit 1
fi
cd "${ROOT_DIR}"

if ! command -v mint >/dev/null 2>&1; then
    echo "pre-commit: mint is not installed."
    echo "Run ./scripts/bootstrap (recommended) or: brew install mint && mint bootstrap"
    exit 1
fi

# BrewUILint runs over the WHOLE tree (Homebrew + Sources), not just the staged files. Its
# nonisolated-extension rule needs to see every `nonisolated` type declaration to flag a bad
# extension on it, and that declaration may live in an unstaged file in another package. Tests
# (Tests/) are intentionally excluded. Builds the tool first (cached in Tools/BrewUILint/.build).
echo "pre-commit: running BrewUILint (whole tree)..."
if ! xcrun swift build --package-path Tools/BrewUILint -c release >/dev/null 2>&1; then
    echo "pre-commit: failed to build BrewUILint (Tools/BrewUILint) — fix the toolchain/build and retry."
    exit 1
fi
brewuilint_bin="$(xcrun swift build --package-path Tools/BrewUILint -c release --show-bin-path)/BrewUILint"
set +e
brewuilint_output="$(find Homebrew HomebrewUpgradeHelper Sources -name '*.swift' -print0 | xargs -0 "${brewuilint_bin}" 2>&1)"
brewuilint_status=$?
set -e
if [[ ${brewuilint_status} -ne 0 ]]; then
    echo ""
    echo "pre-commit: commit blocked due to BrewUILint violations:"
    echo ""
    echo "${brewuilint_output}"
    exit 1
fi

swift_files=()
while IFS= read -r -d '' file; do
    if [[ "${file}" == *.swift ]]; then
        swift_files+=("${file}")
    fi
done < <(git diff --cached --name-only --diff-filter=ACMR -z)

if [[ ${#swift_files[@]} -eq 0 ]]; then
    echo "pre-commit: no staged Swift files, skipping format/lint checks."
    exit 0
fi

# Files with unstaged hunks must not be blanket `git add`ed — that would defeat selective staging.
partially_staged_files=()
worktree_hashes_before=()
for file in "${swift_files[@]}"; do
    if ! git diff --quiet -- "${file}"; then
        partially_staged_files+=("${file}")
    fi
    worktree_hashes_before+=("$(git hash-object -w "${file}")")
done

echo "pre-commit: formatting staged Swift files (mint run swiftformat)..."
mint run swiftformat "${swift_files[@]}"

echo "pre-commit: applying auto-fixes (mint run swiftlint --fix)..."
set +e
mint run swiftlint lint --fix --quiet "${swift_files[@]}"
fix_status=$?
set -e

if [[ ${fix_status} -ne 0 ]]; then
    echo "pre-commit: swiftlint auto-fix reported unresolved issues; running final validation."
fi

files_needing_manual_stage=()
for index in "${!swift_files[@]}"; do
    file="${swift_files[index]}"
    worktree_hash_before="${worktree_hashes_before[index]}"
    worktree_hash_after="$(git hash-object -w "${file}")"
    if [[ "${worktree_hash_before}" == "${worktree_hash_after}" ]]; then
        continue
    fi

    is_partial=false
    if ((${#partially_staged_files[@]} > 0)); then
        for partial in "${partially_staged_files[@]}"; do
            if [[ "${file}" == "${partial}" ]]; then
                is_partial=true
                break
            fi
        done
    fi

    if [[ "${is_partial}" == true ]]; then
        files_needing_manual_stage+=("${file}")
    else
        git add -- "${file}"
    fi
done

if [[ ${#files_needing_manual_stage[@]} -gt 0 ]]; then
    echo ""
    echo "pre-commit: formatter/linter updated partially staged file(s)."
    echo "Re-stage your intended changes (e.g. git add -p) and commit again:"
    printf '  - %s\n' "${files_needing_manual_stage[@]}"
    exit 1
fi

echo "pre-commit: validating lint status..."
set +e
lint_output="$(mint run swiftlint lint --strict --quiet "${swift_files[@]}" 2>&1)"
lint_status=$?
set -e

if [[ ${lint_status} -ne 0 ]]; then
    echo ""
    echo "pre-commit: commit blocked due to unresolved SwiftLint violations."
    echo "Fix the issues below, stage changes, and commit again:"
    echo ""
    echo "${lint_output}"
    exit 1
fi

echo "pre-commit: checks passed."
exit 0