#!/usr/bin/env bash
# agents-tools-version: 2
# Copyright (C) 2026 Rootiest
# SPDX-License-Identifier: AGPL-3.0-or-later
#
# version-bump <precommit|prepmsg> [msgfile]
#
# Maintains <repo>/.version (MAJOR.MINOR.PATCH). MAJOR is manual-only.
# MINOR bumps when the tracked directory set changes between HEAD and the
# staged index; PATCH bumps on any other commit. Never blocks a commit:
# all hook paths exit 0 even on unexpected errors.

mode="${1:-}"
root="$(git rev-parse --show-toplevel 2>/dev/null)" || exit 0
vfile="$root/.version"

read_dirset() {
    # $1: HEAD|INDEX — print sorted unique content dirs (dot-dirs excluded)
    local listing
    if [ "$1" = HEAD ]; then
        listing="$(git ls-tree -r --name-only HEAD 2>/dev/null || true)"
    else
        listing="$(git ls-files 2>/dev/null || true)"
    fi
    printf '%s\n' "$listing" \
        | while IFS= read -r f; do [ -n "$f" ] && dirname "$f"; done \
        | { grep -v '^\.' || true; } \
        | sort -u
}

bump_precommit() {
    [ -f "$vfile" ] || printf '1.0.0\n' > "$vfile"

    # First commit: establish the baseline, no bump.
    if ! git rev-parse --verify -q HEAD >/dev/null 2>&1; then
        grep -Eq '^[0-9]+\.[0-9]+\.[0-9]+$' "$vfile" || printf '1.0.0\n' > "$vfile"
        git add -- "$vfile" 2>/dev/null || true
        return 0
    fi

    local ver major minor patch
    ver="$(head -n1 "$vfile")"
    if printf '%s' "$ver" | grep -Eq '^[0-9]+\.[0-9]+\.[0-9]+$'; then
        IFS=. read -r major minor patch <<< "$ver"
    else
        # Corrupt/partial .version (e.g. "1." or "abc") → reset to a clean baseline.
        major=1; minor=0; patch=0
    fi

    if [ "$(read_dirset HEAD)" != "$(read_dirset INDEX)" ]; then
        minor=$((minor + 1)); patch=0
    else
        patch=$((patch + 1))
    fi
    printf '%s.%s.%s\n' "$major" "$minor" "$patch" > "$vfile"
    git add -- "$vfile" 2>/dev/null || true
}

bump_prepmsg() {
    local msgfile="${1:-}" version first rest
    [ -n "$msgfile" ] && [ -f "$msgfile" ] || return 0
    [ -f "$vfile" ] || return 0
    version="$(head -n1 "$vfile")"
    [ -n "$version" ] || return 0
    head -n1 "$msgfile" | grep -qF "(v$version)" && return 0
    first="$(head -n1 "$msgfile")"
    rest="$(tail -n +2 "$msgfile")"
    if [ -n "$rest" ]; then
        { printf '%s (v%s)\n' "$first" "$version"; printf '%s\n' "$rest"; } > "$msgfile"
    else
        printf '%s (v%s)\n' "$first" "$version" > "$msgfile"
    fi
}

case "$mode" in
    precommit) bump_precommit ;;
    prepmsg)   bump_prepmsg "${2:-}" ;;
    *) echo "version-bump: unknown mode '$mode'" >&2; exit 2 ;;
esac
exit 0