<?php
/*************************************************************
# 076 License

Copyright (c) テクニカル諏訪子

Permission is hereby granted to any person obtaining a copy of the software
Little Beast (the "Software") to use, modify, merge, copy, publish, distribute,
sublicense, and/or sell copies of the Software, subject to the following conditions:

    1. **Origin Attribution**:
       - You must not misrepresent the origin of the Software; you must not claim
         you created the original Software.
       - If the Software is used in a product, you must either:
         a. Provide clear attribution in the product's documentation, user interface,
            or other visible areas, **OR**
         b. Pay the original developers a fee they specify in writing.
    2. **Usage Restriction**:
       - The Software, or any derivative works, dependencies, or libraries
         incorporating it, must not be used for censorship or to suppress freedom of
         speech, expression, or creativity. Prohibited uses include, but are not
         limited to:
         - Censorship of so-called "hate speech", visuals, non-mainstream opinions,
           ideas, or objective reality.
         - Tools or systems designed to restrict access to information or
           artistic works.
    3. **Notice Preservation**:
       - This license and the above copyright notice must remain intact in all copies
         of the source code.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
namespace Site\Controller;

use Std\Lib\Git\Diff;
use Std\Lib\Git\GitException;
use Std\Lib\Git\Repository;
use Std\Lib\Gitler\Federation;
use Std\Lib\Gitler\Gitler as Hosting;
use Std\Lib\Gitler\Issues;
use Std\Lib\Gitler\Notify;
use Std\Lib\Gitler\Pulls;

/**
 * Gitlerのプルリクエスト（比較・作成、コミット、変更されたファイルと行へのコメント、レビュー、マージ）とフォーク
 *
 * 会話のページはGitlerIssuesのissue()（プルリクエストならgitler/pull）。
 */
trait GitlerPulls {
  //////// フォーク

  /** …/fork（POST） */
  public function fork(array $params): void {
    $this->load($params);
    if (!$this->user) $this->redirect('/login');
    if ($_SERVER['REQUEST_METHOD'] !== 'POST' || !$this->csrfOk()) $this->redirect($this->repoUrl());
    $res = Hosting::fork($this->user, $this->owner, $this->name);
    if (!$res->isSuccess) $this->message((string)$res->message, $this->repoUrl());
    $this->redirect('/gitler/'.$res->data['owner'].'/'.rawurlencode($res->data['name']));
  }

  /** …/forks */
  public function forks(array $params): void {
    $this->load($params);
    $list = [];
    foreach (Hosting::forks($this->owner, $this->name) as [$o, $n]) {
      if (Hosting::access($this->user, $o, $n) === Hosting::NONE) continue;
      $list[] = ['owner' => $o, 'name' => $n, 'url' => '/gitler/'.$o.'/'.rawurlencode($n)];
    }
    $this->renderRepo('gitler/forks', 'フォーク', ['list' => $list]);
  }

  //////// 比較と作成

  /** …/compare?base=&head=（headは「ブランチ」又は「所有者/名前:ブランチ」（フォーク）） */
  public function compare(array $params): void {
    $this->loadPulls($params);
    $base = trim((string)($_REQUEST['base'] ?? $this->defaultBranch()));
    $head = trim((string)($_REQUEST['head'] ?? ''));
    $error = '';
    $heads = $this->headChoices();
    $baseId = $this->repo->refs->resolve('refs/heads/'.$base);
    $found = $head !== '' ? $this->resolveHead($head) : null;
    $vars = ['base' => $base, 'head' => $head, 'branches' => array_map(fn($r) => substr($r, 11), array_keys($this->repo->refs->all('refs/heads/'))), 'heads' => $heads,
             'commits' => [], 'files' => [], 'stats' => null, 'canPull' => $this->canPull(), 'in' => ['title' => '', 'body' => ''], 'ready' => false, 'note' => ''];
    if ($head !== '' && ($found === null || $baseId === null)) {
      $vars['note'] = 'ブランチが有りません。';
    } else if ($found !== null) {
      [$kind, $headArr, $headId] = $found;
      $cmp = Pulls::compare($this->repo, $baseId, $headId);
      if (empty($cmp['commits'])) {
        $vars['note'] = "「{$base}」に無いコミットが有りません。";
      } else {
        $vars['commits'] = array_map(fn($id) => $this->presentCommit($this->repo->commit($id)), array_reverse($cmp['commits']));
        [$vars['files'], $vars['stats']] = $this->diffFiles($cmp['mergeBase'], $headId, null, []);
        $first = $this->repo->commit($cmp['commits'][0]);
        $vars['in'] = count($cmp['commits']) === 1
          ? ['title' => $first->subject(), 'body' => trim(substr($first->message, strlen($first->subject())))]
          : ['title' => $kind === 'fork' ? $headArr['branch'] : $head, 'body' => ''];
        $vars['ready'] = true;
        if ($_SERVER['REQUEST_METHOD'] === 'POST') {
          $vars['in'] = ['title' => (string)($_POST['title'] ?? ''), 'body' => str_replace("\r\n", "\n", (string)($_POST['body'] ?? ''))];
          if (!$this->csrfOk()) {
            $error = 'セッションの有効期限が切れました。もう一度お試し下さい。';
          } else if (!$this->canPull()) {
            $error = 'プルリクエストを作る権限が有りません（管理者に「Gitのプルリクエスト」のロールを付けて貰って下さい）。';
          } else {
            $res = Pulls::open($this->owner, $this->name, $this->me(), $vars['in']['title'], $vars['in']['body'], $base, $kind, $headArr, $headId);
            if ($res->isSuccess) $this->redirect($this->repoUrl().'/pulls/'.$res->data['number']);
            if (isset($res->data['number'])) $this->redirect($this->repoUrl().'/pulls/'.$res->data['number']);
            $error = (string)$res->message;
          }
        }
      }
    }
    $this->renderRepo('gitler/compare', 'プルリクエストを作る', $vars + ['error' => $error]);
  }

  /** headの選択肢（このリポジトリのブランチと、見られるフォークのブランチ） */
  private function headChoices(): array {
    $out = [['label' => "{$this->owner}/{$this->name}", 'items' => array_map(fn($r) => substr($r, 11), array_keys($this->repo->refs->all('refs/heads/')))]];
    foreach (Hosting::forks($this->owner, $this->name) as [$o, $n]) {
      if (Hosting::access($this->user, $o, $n) === Hosting::NONE) continue;
      $out[] = ['label' => "{$o}/{$n}", 'items' => array_map(fn($r) => "{$o}/{$n}:".substr($r, 11), array_keys(Hosting::open($o, $n)->refs->all('refs/heads/')))];
    }
    return $out;
  }

  /**
   * headを解決する（フォークのコミットはこのリポジトリに持って来る）
   *
   * @return array|null  [kind, head, headId]
   */
  private function resolveHead(string $head): ?array {
    if (preg_match('#^([A-Za-z0-9]+)/([A-Za-z0-9._-]+):(.+)$#', $head, $m)) {
      [, $o, $n, $branch] = $m;
      if (!Hosting::exists($o, $n) || Hosting::meta($o, $n)['forkOf'] !== "{$this->owner}/{$this->name}" || Hosting::access($this->user, $o, $n) === Hosting::NONE) return null;
      $fork = Hosting::open($o, $n);
      $id = $fork->refs->resolve('refs/heads/'.$branch);
      if ($id === null) return null;
      try {
        Pulls::fetch($fork, $this->repo, $id);
      } catch (GitException) {
        return null;
      }
      return ['fork', ['owner' => $o, 'name' => $n, 'branch' => $branch], $id];
    }
    $id = $this->repo->refs->resolve('refs/heads/'.$head);
    return $id === null ? null : ['branch', ['owner' => $this->owner, 'name' => $this->name, 'branch' => $head], $id];
  }

  //////// プルリクエストのページ

  /** …/pulls/{n}/commits */
  public function pullCommits(array $params): void {
    [$issue, $range] = $this->loadPull($params);
    $list = [];
    if ($range !== null) foreach (array_reverse(Pulls::compare($this->repo, $range[0], $range[1])['commits']) as $id) $list[] = $this->presentCommit($this->repo->commit($id));
    $this->renderRepo('gitler/pullcommits', '#'.$issue['number'].' '.$issue['title'], $this->pullHead($issue) + ['list' => $list, 'tab' => 'commits']);
  }

  /** …/pulls/{n}/files?path=&side=&line=（行を選ぶとコメントの欄） */
  public function pullFiles(array $params): void {
    [$issue, $range] = $this->loadPull($params);
    $n = $issue['number'];
    $error = '';
    if ($_SERVER['REQUEST_METHOD'] === 'POST') {
      $error = $this->csrfOk() ? $this->issueAction($issue) : 'セッションの有効期限が切れました。もう一度お試し下さい。';
      $issue = $this->issueDb->get($n) ?? $issue;
    }
    $files = [];
    $stats = null;
    if ($range !== null) {
      $mb = (new \Std\Lib\Git\Walk($this->repo))->mergeBase($range[0], $range[1]);
      $form = isset($_GET['path'], $_GET['line']) ? ['path' => (string)$_GET['path'], 'side' => ($_GET['side'] ?? 'new') === 'old' ? 'old' : 'new', 'line' => (int)$_GET['line']] : null;
      [$files, $stats] = $this->diffFiles($mb, $range[1], $this->canReview() ? $form : null, $issue);
    }
    $me = $this->user ? Issues::authorKey($this->me()) : '';
    $pending = count(array_filter($issue['comments'], fn($c) => !empty($c['pending']) && Issues::authorKey($c['author']) === $me));
    $this->renderRepo('gitler/pullfiles', '#'.$n.' '.$issue['title'], $this->pullHead($issue) + [
      'files' => $files, 'stats' => $stats, 'tab' => 'files', 'error' => $error, 'pending' => $pending, 'canReview' => $this->canReview(),
      'canApprove' => $this->canReview() && ($issue['author']['user'] ?? null) !== $this->user?->username, 'filesUrl' => $this->repoUrl().'/pulls/'.$n.'/files',
    ]);
  }

  /** 会話のページ（issue()）に足す物 */
  private function pullVars(array $issue): array {
    $p = $issue['pull'];
    try {
      $m = Pulls::mergeability($this->repo, $issue);
    } catch (GitException) {
      $m = ['state' => 'error', 'conflicts' => [], 'baseId' => null];
    }
    // レビュアー毎の最後の承認・変更の依頼
    $latest = [];
    foreach ($issue['reviews'] ?? [] as $r) if ($r['state'] !== 'commented') $latest[Issues::authorKey($r['author'])] = $r;
    $branchId = $p['kind'] === 'branch' ? $this->repo->refs->resolve('refs/heads/'.$p['head']['branch']) : null;
    $msg = "Merge pull request #{$issue['number']} from ".$this->headLabel($p)."\n\n{$issue['title']}";
    return $this->pullHead($issue) + [
      'merge' => $m, 'tab' => 'conversation',
      'approvals' => array_values(array_map(fn($r) => ['who' => $this->who($r['author']), 'state' => $r['state']], $latest)),
      'canMerge' => !$this->meta['archived'] && $this->access >= Hosting::WRITE && in_array($m['state'], ['ff', 'clean', 'conflict'], true),
      'mergeMessage' => $msg, 'squashMessage' => "{$issue['title']} (#{$issue['number']})",
      'canDeleteBranch' => !$this->meta['archived'] && $this->access >= Hosting::WRITE && $issue['state'] === 'closed' && $branchId !== null && $branchId === $p['headId']
                           && $p['head']['branch'] !== $this->defaultBranch(),
      'fetchCommand' => 'git fetch origin '.Pulls::ref($issue['number']).':pr-'.$issue['number'],
    ];
  }

  /** プルリクエストのページの頭（タブ等） */
  private function pullHead(array $issue): array {
    $p = $issue['pull'];
    $u = $this->repoUrl().'/pulls/'.$issue['number'];
    $range = Pulls::range($this->repo, $issue);
    $count = $range !== null ? count(Pulls::compare($this->repo, $range[0], $range[1])['commits']) : 0;
    $headUrl = match ($p['kind']) {
      'branch' => $this->url('tree', $p['head']['branch'], ''),
      'fork' => '/gitler/'.$p['head']['owner'].'/'.rawurlencode($p['head']['name']).'/tree?ref='.rawurlencode($p['head']['branch']),
      default => '',
    };
    return ['pull' => $p, 'pullUrl' => $u, 'commitsTabUrl' => $u.'/commits', 'filesTabUrl' => $u.'/files', 'commitCount' => $count,
            'headLabel' => $this->headLabel($p), 'headUrl' => $headUrl, 'issue' => $issue, 'who' => $this->who($issue['author']),
            'merged' => !empty($p['merged']), 'mergedBy' => !empty($p['merged']) ? $this->who($p['merged']['by']) : null];
  }

  private function headLabel(array $p): string {
    return match ($p['kind']) {
      'fork' => "{$p['head']['owner']}/{$p['head']['name']}:{$p['head']['branch']}",
      'agit' => "{$p['head']['user']}:{$p['head']['topic']}（AGit）",
      default => (string)$p['head']['branch'],
    };
  }

  /**
   * プルリクエストのPOST（GitlerIssuesのissueActionから）
   *
   * @return string  エラー（成功したらリダイレクト）
   */
  private function pullAction(array $issue, string $do): string {
    $n = $issue['number'];
    $url = $this->repoUrl().'/pulls/'.$n;
    if (!$this->user) return 'ログインして下さい。';
    if ($this->meta['archived']) return 'アーカイブされたリポジトリです（読むだけ）。';
    $me = $this->me();
    $body = str_replace("\r\n", "\n", (string)($_POST['body'] ?? ''));

    if ($do === 'merge') {
      if ($this->access < Hosting::WRITE) return 'マージする権限が有りません。';
      $res = Pulls::merge($this->owner, $this->name, $n, $this->user, (string)($_POST['method'] ?? 'merge'), (string)($_POST['message'] ?? ''));
      if (!$res->isSuccess) return (string)$res->message;
      $this->redirect($url);
    }
    if ($do === 'deleteBranch') {
      $p = $issue['pull'];
      if ($this->access < Hosting::WRITE || $p['kind'] !== 'branch' || $p['head']['branch'] === $this->defaultBranch()) return '削除出来ません。';
      try {
        $this->repo->refs->update('refs/heads/'.$p['head']['branch'], null, $p['headId']);
      } catch (GitException) {
        return 'ブランチが変わっているので削除出来ません。';
      }
      $this->issueDb->update($n, function(array $i) use ($me, $p): array {
        $i['events'][] = ['type' => 'branchDeleted', 'by' => $me, 'at' => time(), 'branch' => $p['head']['branch']];
        return $i;
      });
      $this->redirect($url);
    }
    if (!$this->canReview()) return 'コメントする権限が有りません。';
    if ($do === 'inline' || $do === 'inlinePending') {
      $at = ['path' => (string)($_POST['path'] ?? ''), 'side' => ($_POST['side'] ?? 'new') === 'old' ? 'old' : 'new', 'line' => (int)($_POST['line'] ?? 0),
             'commit' => $issue['pull']['headId'], 'pending' => $do === 'inlinePending'];
      $at['hunk'] = $this->hunkFor($issue, $at['path'], $at['side'], $at['line']);
      if ($at['hunk'] === null) return 'その行が有りません。';
      $res = $this->issueDb->inlineComment($n, $me, $body, $at);
      if (!$res->isSuccess) return (string)$res->message;
      if ($do === 'inline') $this->notifyComment($res->data['issue'], $res->data['comment']);
      $this->redirect($url.'/files#c'.$res->data['comment']['id']);
    }
    if ($do === 'reply') {
      $res = $this->issueDb->inlineComment($n, $me, $body, ['replyTo' => (int)($_POST['id'] ?? 0)]);
      if (!$res->isSuccess) return (string)$res->message;
      $this->notifyComment($res->data['issue'], $res->data['comment']);
      $back = ($_POST['back'] ?? '') === 'files' ? $url.'/files' : $url;
      $this->redirect($back.'#c'.$res->data['comment']['id']);
    }
    if ($do === 'review') {
      $state = (string)($_POST['state'] ?? 'commented');
      if ($state !== 'commented' && ($issue['author']['user'] ?? null) === $this->user->username) return '自分のプルリクエストは承認・変更の依頼が出来ません。';
      $res = $this->issueDb->submitReview($n, $me, $state, $body, $issue['pull']['headId']);
      if (!$res->isSuccess) return (string)$res->message;
      Notify::reviewed($this->owner, $this->name, $this->meta, $this->issueDb, $res->data['issue'], $res->data['review']);
      $this->redirect($url.'#r'.$res->data['review']['id']);
    }
    return '';
  }

  private function notifyComment(array $issue, array $c): void {
    Federation::commentAdded($this->owner, $this->name, $this->meta, $issue, $c);
    Notify::commented($this->owner, $this->name, $this->meta, $this->issueDb, $issue, $c);
  }

  /** 行へのコメントの表示用の前の行（無ければnull） */
  private function hunkFor(array $issue, string $path, string $side, int $line): ?array {
    $range = Pulls::range($this->repo, $issue);
    if ($range === null || $path === '' || $line < 1) return null;
    $mb = (new \Std\Lib\Git\Walk($this->repo))->mergeBase($range[0], $range[1]);
    foreach (Diff::trees($this->repo, $mb !== null ? $this->repo->commit($mb)->tree : null, $this->repo->commit($range[1])->tree) as $ch) {
      if ((($ch['new'] ?? $ch['old'])[1]) !== $path) continue;
      $add = $del = 0;
      $budget = self::MAX_DIFF_TOTAL;
      $f = $this->presentChange($ch, $range[1], $add, $del, $budget);
      foreach ($f['hunks'] as $h) {
        foreach ($h['rows'] as $k => $r) {
          if ($r[$side] !== $line || ($side === 'new' && $r['op'] === '-') || ($side === 'old' && $r['op'] !== '-')) continue;
          return array_map(fn($x) => $x['op'].$x['text'], array_slice($h['rows'], max(0, $k - 3), min(4, $k + 1)));
        }
      }
    }
    return null;
  }

  /**
   * 変更されたファイル（行へのコメント付き）
   *
   * @param array|null $form  コメントの欄を出す行（path、side、line）
   * @param array $issue  プルリクエスト（コメントを付けない場合は空）
   * @return array  [ファイル, 統計]
   */
  private function diffFiles(?string $from, string $to, ?array $form, array $issue): array {
    $changes = Diff::trees($this->repo, $from !== null ? $this->repo->commit($from)->tree : null, $this->repo->commit($to)->tree);
    $add = $del = 0;
    $budget = self::MAX_DIFF_TOTAL;
    // スレッド（今のheadへのコメントだけ）
    $threads = [];
    $replies = [];
    $me = $this->user ? Issues::authorKey($this->me()) : '';
    foreach ($issue['comments'] ?? [] as $c) {
      if (!isset($c['path']) || (!empty($c['pending']) && Issues::authorKey($c['author']) !== $me)) continue;
      if ($c['replyTo'] !== null) $replies[$c['replyTo']][] = $c;
      else if ($c['commit'] === $to) $threads["{$c['path']}\0{$c['side']}\0{$c['line']}"][] = $c;
    }
    $files = [];
    foreach (array_slice($changes, 0, self::MAX_DIFF_FILES) as $i => $ch) {
      $f = $this->presentChange($ch, $to, $add, $del, $budget);
      $f['index'] = $i;
      foreach ($f['hunks'] as $hk => $h) {
        foreach ($h['rows'] as $rk => $r) {
          $side = $r['op'] === '-' ? 'old' : 'new';
          $line = (int)$r[$side];
          $key = "{$f['path']}\0{$side}\0{$line}";
          $r['anchor'] = "f{$i}-{$side}{$line}";
          $r['link'] = !empty($issue) && $this->canReview() ? '?'.http_build_query(['path' => $f['path'], 'side' => $side, 'line' => $line]).'#'.$r['anchor'] : '';
          $r['threads'] = array_map(fn($c) => $this->presentInline($c, $replies[$c['id']] ?? []), $threads[$key] ?? []);
          $r['form'] = $form !== null && $form['path'] === $f['path'] && $form['side'] === $side && $form['line'] === $line ? ['path' => $f['path'], 'side' => $side, 'line' => $line] : null;
          $f['hunks'][$hk]['rows'][$rk] = $r;
        }
      }
      $files[] = $f;
    }
    return [$files, ['files' => count($changes), 'add' => $add, 'del' => $del, 'truncated' => count($changes) > self::MAX_DIFF_FILES]];
  }

  /** 行へのコメントとその返信 */
  private function presentInline(array $c, array $replies): array {
    $one = function(array $x): array {
      $mine = $this->user && ($x['author']['user'] ?? null) === $this->user->username;
      return ['id' => $x['id'], 'who' => $this->who($x['author']), 'html' => $this->bodyHtml($x['body'], !empty($x['html'])), 'date' => date('Y-m-d H:i', $x['created']),
              'pending' => !empty($x['pending']), 'canDelete' => !$this->meta['archived'] && ($mine || $this->access >= Hosting::ADMIN)];
    };
    return $one($c) + ['path' => $c['path'], 'line' => $c['line'], 'side' => $c['side'], 'hunk' => $c['hunk'] ?? [], 'replies' => array_map($one, $replies)];
  }

  //////// 共通

  private function loadPulls(array $params): void {
    $this->load($params);
    if (!$this->meta['pulls']) $this->notFound();
    $this->issueDb = new Issues($this->repo);
  }

  /** @return array  [プルリクエスト, 範囲] */
  private function loadPull(array $params): array {
    $this->loadPulls($params);
    $issue = $this->issueDb->get((int)($params['n'] ?? 0));
    if ($issue === null || !isset($issue['pull'])) $this->notFound();
    return [$issue, Pulls::range($this->repo, $issue)];
  }

  /** プルリクエストを作れるか */
  private function canPull(): bool {
    return $this->user !== null && $this->meta['pulls'] && !$this->meta['archived'] && Hosting::userCan($this->user, 'pulls');
  }

  /** レビューとコメントが出来るか */
  private function canReview(): bool {
    return $this->user !== null && !$this->meta['archived'] && (Hosting::userCan($this->user, 'issues') || Hosting::userCan($this->user, 'pulls'));
  }
}