#!/usr/bin/env php
<?php
/* Copyright (C) 2026 Moko Consulting <hello@mokoconsulting.tech>
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 * FILE INFORMATION
 * DEFGROUP: moko-platform.CLI
 * INGROUP: moko-platform
 * REPO: https://git.mokoconsulting.tech/MokoConsulting/moko-platform
 * PATH: /cli/changelog_prune.php
 * BRIEF: Prune old CHANGELOG.md entries — keeps [Unreleased] + last N releases
 *
 * Usage:
 *   php changelog_prune.php --path /repo --keep 5
 *   php changelog_prune.php --path /repo --keep 3 --dry-run
 */

declare(strict_types=1);

$path = '.';
$keep = 5;
$dryRun = false;

foreach ($argv as $i => $arg) {
    if ($arg === '--path' && isset($argv[$i + 1])) $path = $argv[$i + 1];
    if ($arg === '--keep' && isset($argv[$i + 1])) $keep = (int)$argv[$i + 1];
    if ($arg === '--dry-run') $dryRun = true;
    if ($arg === '--help') {
        echo "changelog_prune — Keep [Unreleased] + last N versioned entries\n\n";
        echo "Usage: php changelog_prune.php --path . --keep 5 [--dry-run]\n\n";
        echo "Options:\n";
        echo "  --path    Repository path (default: .)\n";
        echo "  --keep    Number of versioned releases to keep (default: 5)\n";
        echo "  --dry-run Preview without writing\n";
        exit(0);
    }
}

$changelog = realpath($path) . '/CHANGELOG.md';
if (!file_exists($changelog)) {
    fwrite(STDERR, "No CHANGELOG.md found at {$path}\n");
    exit(1);
}

$content = file_get_contents($changelog);
$lines = explode("\n", $content);

// Split into sections by ## headings
$sections = [];
$current = [];
$currentHeading = null;

foreach ($lines as $line) {
    if (preg_match('/^## /', $line)) {
        if ($currentHeading !== null) {
            $sections[] = ['heading' => $currentHeading, 'lines' => $current];
        }
        $currentHeading = $line;
        $current = [$line];
    } else {
        $current[] = $line;
    }
}
if ($currentHeading !== null) {
    $sections[] = ['heading' => $currentHeading, 'lines' => $current];
}

// Find the header (everything before the first ## section)
$header = [];
$contentLines = explode("\n", $content);
foreach ($contentLines as $line) {
    if (preg_match('/^## /', $line)) {
        break;
    }
    $header[] = $line;
}

// Separate [Unreleased] from versioned sections
$unreleased = null;
$versioned = [];

foreach ($sections as $section) {
    if (preg_match('/\[Unreleased\]/i', $section['heading'])) {
        $unreleased = $section;
    } else {
        $versioned[] = $section;
    }
}

$totalVersioned = count($versioned);
$pruned = $totalVersioned - $keep;

if ($pruned <= 0) {
    echo "CHANGELOG has {$totalVersioned} versioned entries — nothing to prune (keeping {$keep})\n";
    exit(0);
}

// Keep only the first N versioned sections
$keptVersioned = array_slice($versioned, 0, $keep);
$droppedVersioned = array_slice($versioned, $keep);

// Report
echo "CHANGELOG: {$totalVersioned} versioned entries found\n";
echo "  Keeping: {$keep} most recent\n";
echo "  Pruning: {$pruned} old entries\n";

foreach ($droppedVersioned as $section) {
    $heading = trim($section['heading']);
    echo "    - {$heading}\n";
}

if ($dryRun) {
    echo "\n(dry-run) No changes written\n";
    exit(0);
}

// Rebuild the file
$output = implode("\n", $header);

if ($unreleased !== null) {
    $output .= implode("\n", $unreleased['lines']) . "\n";
}

foreach ($keptVersioned as $section) {
    $output .= implode("\n", $section['lines']) . "\n";
}

// Clean up excessive blank lines at end
$output = rtrim($output) . "\n";

file_put_contents($changelog, $output);
echo "\nCHANGELOG pruned: removed {$pruned} old entries\n";
exit(0);