<?php
declare(strict_types=1);

final class RuleRepository
{
    public function __construct(private string $baseDir = Settings::DATA_DIR)
    {
    }

    /** @return array<int,array<string,mixed>> */
    public function all(string $username): array
    {
        $data = $this->read($username);
        return array_values($data['rules'] ?? []);
    }

    /** @return array<string,mixed>|null */
    public function find(string $username, string $id): ?array
    {
        foreach ($this->all($username) as $rule) {
            if (($rule['id'] ?? '') === $id) {
                return $rule;
            }
        }
        return null;
    }

    /** @param array<string,mixed> $rule @return array<string,mixed> */
    public function create(string $username, array $rule): array
    {
        $data = $this->read($username);
        $now = time();
        $rule['id'] = bin2hex(random_bytes(12));
        $rule['created_at'] = $now;
        $rule['updated_at'] = $now;
        $data['rules'][] = $rule;
        $this->write($username, $data);
        return $rule;
    }

    /** @param array<string,mixed> $patch @return array<string,mixed> */
    public function update(string $username, string $id, array $patch): array
    {
        $data = $this->read($username);
        foreach ($data['rules'] as $i => $rule) {
            if (($rule['id'] ?? '') === $id) {
                $updated = array_merge($rule, $patch, ['id' => $id, 'updated_at' => time()]);
                $data['rules'][$i] = $updated;
                $this->write($username, $data);
                return $updated;
            }
        }
        throw new RuntimeException('Rule not found');
    }

    public function delete(string $username, string $id): void
    {
        $data = $this->read($username);
        $before = count($data['rules']);
        $data['rules'] = array_values(array_filter($data['rules'], static fn (array $rule): bool => ($rule['id'] ?? '') !== $id));
        if (count($data['rules']) === $before) {
            throw new RuntimeException('Rule not found');
        }
        $this->write($username, $data);
    }

    /** @return array{rules:array<int,array<string,mixed>>} */
    private function read(string $username): array
    {
        $path = $this->path($username);
        if (!is_file($path)) {
            return ['rules' => []];
        }
        $data = json_decode((string)file_get_contents($path), true);
        return is_array($data) && isset($data['rules']) && is_array($data['rules']) ? $data : ['rules' => []];
    }

    /** @param array{rules:array<int,array<string,mixed>>} $data */
    private function write(string $username, array $data): void
    {
        $path = $this->path($username);
        $dir = dirname($path);
        if (!is_dir($dir)) {
            mkdir($dir, 0700, true);
        }
        $tmp = $path . '.tmp.' . getmypid();
        file_put_contents($tmp, json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES), LOCK_EX);
        @chmod($tmp, 0600);
        rename($tmp, $path);
    }

    private function path(string $username): string
    {
        $this->assertUsername($username);
        return rtrim($this->baseDir, '/') . '/users/' . $username . '/rules.json';
    }

    private function assertUsername(string $username): void
    {
        if (!preg_match('/^[A-Za-z0-9._-]+$/', $username)) {
            throw new InvalidArgumentException('Invalid username');
        }
    }
}