<?php

declare(strict_types=1);

namespace Monitor\Api\Repository;

use InvalidArgumentException;
use Monitor\Api\Db\Database;
use Monitor\Api\Http\NotFoundException;

final class TicketRepository
{
    /** @var string[] */
    public const COLUMNS = ['backlog', 'bereit', 'in_arbeit', 'qa', 'testing', 'fertig', 'done'];

    /**
     * Spalten, die der Codeberg-Sync anhand von Issue-Status/Labels pflegt (F14). "qa" und
     * "fertig" sind fuer zukuenftige Labels reserviert und bleiben rein manuell.
     *
     * @var string[]
     */
    private const SYNC_MANAGED_COLUMNS = ['backlog', 'bereit', 'in_arbeit', 'testing', 'done'];

    public function __construct(private readonly Database $db)
    {
    }

    /** @param array<string, mixed> $data @return array<string, mixed> */
    public function create(array $data): array
    {
        $column = $data['column'] ?? 'backlog';
        $this->assertValidColumn($column);

        $now = $this->db->now();
        $stmt = $this->db->pdo()->prepare(
            'INSERT INTO tickets (external_ref, repo, title, description, column_name, type, color, assignee_agent_id, source, created_at, updated_at)
             VALUES (:external_ref, :repo, :title, :description, :column_name, :type, :color, :assignee_agent_id, :source, :created_at, :updated_at)'
        );
        $stmt->execute([
            'external_ref' => $data['external_ref'] ?? null,
            'repo' => $data['repo'] ?? null,
            'title' => $data['title'],
            'description' => $data['description'] ?? null,
            'column_name' => $column,
            'type' => $data['type'] ?? null,
            'color' => $data['color'] ?? null,
            'assignee_agent_id' => $data['assignee_agent_id'] ?? null,
            'source' => $data['source'] ?? 'api',
            'created_at' => $now,
            'updated_at' => $now,
        ]);

        return $this->find((int) $this->db->pdo()->lastInsertId());
    }

    /** @param array<string, mixed> $changes @return array<string, mixed> */
    public function update(int $id, array $changes): array
    {
        if ($this->find($id) === null) {
            throw new NotFoundException('Ticket nicht gefunden: ' . $id);
        }

        $fields = [];
        $params = ['id' => $id];

        if (array_key_exists('column', $changes)) {
            $this->assertValidColumn($changes['column']);
            $fields[] = 'column_name = :column_name';
            $params['column_name'] = $changes['column'];
        }
        foreach (['title', 'description', 'type', 'color'] as $key) {
            if (array_key_exists($key, $changes)) {
                $fields[] = "$key = :$key";
                $params[$key] = $changes[$key];
            }
        }
        if (array_key_exists('assignee_agent_id', $changes)) {
            $fields[] = 'assignee_agent_id = :assignee_agent_id';
            $params['assignee_agent_id'] = $changes['assignee_agent_id'];
        }

        if ($fields === []) {
            return $this->find($id);
        }

        $fields[] = 'updated_at = :updated_at';
        $params['updated_at'] = $this->db->now();

        $sql = 'UPDATE tickets SET ' . implode(', ', $fields) . ' WHERE id = :id';
        $this->db->pdo()->prepare($sql)->execute($params);

        return $this->find($id);
    }

    /** @return array<string, mixed>|null */
    public function find(int $id): ?array
    {
        $stmt = $this->db->pdo()->prepare('SELECT * FROM tickets WHERE id = :id');
        $stmt->execute(['id' => $id]);
        $row = $stmt->fetch();

        return $row === false ? null : $row;
    }

    /**
     * external_ref (Issue-Nummer) ist nur je Repo eindeutig (F26: mehrere Codeberg-Projekte),
     * daher zusaetzlich ueber "repo" ("owner/name") gescoped. $repo bleibt optional/null fuer
     * Tickets ohne Codeberg-Projektbezug.
     *
     * @return array<string, mixed>|null
     */
    public function findByExternalRef(string $externalRef, ?string $repo = null): ?array
    {
        $stmt = $this->db->pdo()->prepare('SELECT * FROM tickets WHERE external_ref = :ref AND repo IS :repo');
        $stmt->execute(['ref' => $externalRef, 'repo' => $repo]);
        $row = $stmt->fetch();

        return $row === false ? null : $row;
    }

    /**
     * Liefert Tickets sortiert nach Spalte und Alter, damit das Frontend die "aelteste 4 +
     * Stapel"-Regel (F4) ohne weitere API-Unterstuetzung umsetzen kann.
     *
     * @return array<int, array<string, mixed>>
     */
    public function all(?string $column = null): array
    {
        if ($column !== null) {
            $this->assertValidColumn($column);
            $stmt = $this->db->pdo()->prepare(
                'SELECT * FROM tickets WHERE column_name = :column ORDER BY created_at ASC, id ASC'
            );
            $stmt->execute(['column' => $column]);

            return $stmt->fetchAll();
        }

        $stmt = $this->db->pdo()->query('SELECT * FROM tickets ORDER BY column_name ASC, created_at ASC, id ASC');

        return $stmt->fetchAll();
    }

    /**
     * Legt ein Ticket aus einem Codeberg-Issue an oder aktualisiert es (Abgleich ueber
     * external_ref). Wird vom Codeberg-Sync fuer Backlog/Done verwendet (F4).
     *
     * @param array<string, mixed> $data
     * @return array<string, mixed>
     */
    public function upsertFromCodeberg(array $data): array
    {
        $existing = $this->findByExternalRef((string) $data['external_ref'], $data['repo'] ?? null);
        if ($existing === null) {
            return $this->create($data + ['source' => 'codeberg']);
        }

        // Manuell auf eine nicht vom Sync verwaltete Spalte bewegte Tickets (z. B. qa/fertig)
        // werden vom periodischen Codeberg-Sync nicht zurueckgesetzt.
        if (!in_array($existing['column_name'], self::SYNC_MANAGED_COLUMNS, true)) {
            return $existing;
        }

        return $this->update((int) $existing['id'], [
            'column' => $data['column'],
            'title' => $data['title'],
            'description' => $data['description'] ?? null,
            'type' => $data['type'] ?? null,
            'color' => $data['color'] ?? null,
        ]);
    }

    /**
     * Billiger "Fingerabdruck" (Anzahl + juengster Aenderungszeitpunkt) fuer den SSE-Endpoint
     * (Realtime\ChangeFeed, F13) - aendert sich bei jedem Anlegen/Verschieben eines Tickets.
     */
    public function fingerprint(): string
    {
        $row = $this->db->pdo()->query('SELECT COUNT(*) AS c, MAX(updated_at) AS m FROM tickets')->fetch();

        return $row['c'] . ':' . ($row['m'] ?? '');
    }

    private function assertValidColumn(mixed $column): void
    {
        if (!is_string($column) || !in_array($column, self::COLUMNS, true)) {
            throw new InvalidArgumentException('Ungueltige Spalte: ' . var_export($column, true));
        }
    }
}