<?php
declare(strict_types=1);

namespace AttHc\Server;

/**
 * Thin DB access layer. All methods return plain arrays, ready to JSON-encode.
 * Timestamps stored as unix seconds (UTC).
 */
final class Store {
    public static function insertHealthcheck(array $row): void {
        $now = time();
        $stmt = Db::pdo()->prepare('INSERT INTO healthchecks
            (id, site_key, started_at, finished_at, technician_id, reporting_url, wp_version, php_version, next_due, created_at, updated_at)
            VALUES (:id, :site_key, :started_at, NULL, :technician_id, :reporting_url, :wp_version, :php_version, :next_due, :created_at, :updated_at)');
        $stmt->execute([
            ':id'            => $row['id'],
            ':site_key'      => $row['site_key'],
            ':started_at'    => $row['started_at'],
            ':technician_id' => $row['technician_id'] ?? null,
            ':reporting_url' => $row['reporting_url'],
            ':wp_version'    => $row['wp_version'] ?? null,
            ':php_version'   => $row['php_version'] ?? null,
            ':next_due'      => $row['next_due'] ?? null,
            ':created_at'    => $now,
            ':updated_at'    => $now,
        ]);
    }

    public static function getHealthcheck(string $id): ?array {
        $stmt = Db::pdo()->prepare('SELECT * FROM healthchecks WHERE id = ?');
        $stmt->execute([$id]);
        $row = $stmt->fetch();
        return $row ?: null;
    }

    public static function updateHealthcheck(string $id, ?int $finishedAt): bool {
        $stmt = Db::pdo()->prepare('UPDATE healthchecks SET finished_at = :finished_at, updated_at = :updated_at WHERE id = :id');
        $stmt->execute([
            ':id'           => $id,
            ':finished_at'  => $finishedAt,
            ':updated_at'   => time(),
        ]);
        return $stmt->rowCount() > 0;
    }

    /**
     * Set (or clear, with null) the next-due date on one healthcheck.
     *
     * Deliberately separate from updateHealthcheck() so that finishing or
     * reopening a session never touches the scheduled date, and vice versa.
     */
    public static function setNextDue(string $id, ?string $nextDue): bool {
        $stmt = Db::pdo()->prepare('UPDATE healthchecks SET next_due = :next_due, updated_at = :updated_at WHERE id = :id');
        $stmt->execute([
            ':id'         => $id,
            ':next_due'   => $nextDue,
            ':updated_at' => time(),
        ]);
        return $stmt->rowCount() > 0;
    }

    public static function upsertStep(string $healthcheckId, string $stepId, array $row): void {
        $pdo    = Db::pdo();
        $driver = $pdo->getAttribute(\PDO::ATTR_DRIVER_NAME);

        $base = 'INSERT INTO step_updates
            (healthcheck_id, step_id, status, notes, autocheck_json, reporting_url, updated_at)
            VALUES (:hc, :sid, :status, :notes, :autocheck, :reporting_url, :updated_at)';

        if ($driver === 'mysql') {
            // MySQL: VALUES(col) in ON DUPLICATE KEY UPDATE is deprecated in 8.0.20+
            // but still works; the new spelling needs an alias on the row. Stick
            // with VALUES() for broader compatibility back to MySQL 5.7.
            $sql = $base . '
                ON DUPLICATE KEY UPDATE
                    status         = VALUES(status),
                    notes          = VALUES(notes),
                    autocheck_json = VALUES(autocheck_json),
                    reporting_url  = VALUES(reporting_url),
                    updated_at     = VALUES(updated_at)';
        } else {
            // SQLite (and PostgreSQL, by happy accident).
            $sql = $base . '
                ON CONFLICT (healthcheck_id, step_id) DO UPDATE SET
                    status         = excluded.status,
                    notes          = excluded.notes,
                    autocheck_json = excluded.autocheck_json,
                    reporting_url  = excluded.reporting_url,
                    updated_at     = excluded.updated_at';
        }

        $stmt = $pdo->prepare($sql);
        $stmt->execute([
            ':hc'            => $healthcheckId,
            ':sid'           => $stepId,
            ':status'        => $row['status'],
            ':notes'         => $row['notes'] ?? '',
            ':autocheck'     => isset($row['autocheck']) ? json_encode($row['autocheck']) : null,
            ':reporting_url' => $row['reporting_url'],
            ':updated_at'    => time(),
        ]);
        // Bump parent's updated_at so list views sort sensibly.
        $pdo->prepare('UPDATE healthchecks SET updated_at = ? WHERE id = ?')
            ->execute([time(), $healthcheckId]);
    }

    /** @return array<int, array> */
    public static function stepsFor(string $healthcheckId): array {
        $stmt = Db::pdo()->prepare('SELECT step_id, status, notes, autocheck_json, reporting_url, updated_at
            FROM step_updates WHERE healthcheck_id = ? ORDER BY updated_at ASC');
        $stmt->execute([$healthcheckId]);
        $rows = $stmt->fetchAll();
        foreach ($rows as &$r) {
            $r['autocheck'] = $r['autocheck_json'] !== null ? json_decode($r['autocheck_json'], true) : null;
            unset($r['autocheck_json']);
        }
        return $rows;
    }

    /** @return array<int, array> */
    public static function listHealthchecksForSite(string $siteKey, int $limit = 50): array {
        $stmt = Db::pdo()->prepare('SELECT * FROM healthchecks WHERE site_key = ? ORDER BY started_at DESC LIMIT ?');
        $stmt->bindValue(1, $siteKey);
        $stmt->bindValue(2, $limit, \PDO::PARAM_INT);
        $stmt->execute();
        return $stmt->fetchAll();
    }

    /**
     * Notes for one step across the last N sessions for a site.
     * @return array<int, array>
     */
    public static function stepHistory(string $stepId, string $siteKey, int $limit = 5, ?string $excludeId = null): array {
        $sql = 'SELECT h.id AS healthcheck_id, h.started_at, h.finished_at, h.reporting_url AS session_reporting_url,
                   s.status, s.notes, s.autocheck_json, s.reporting_url AS step_reporting_url, s.updated_at
            FROM step_updates s
            JOIN healthchecks h ON h.id = s.healthcheck_id
            WHERE s.step_id = ? AND h.site_key = ?';
        $params = [$stepId, $siteKey];
        if ($excludeId !== null && $excludeId !== '') {
            $sql .= ' AND h.id != ?';
            $params[] = $excludeId;
        }
        $sql .= ' ORDER BY h.started_at DESC LIMIT ?';

        $stmt = Db::pdo()->prepare($sql);
        $i = 1;
        foreach ($params as $p) {
            $stmt->bindValue($i++, $p);
        }
        $stmt->bindValue($i, $limit, \PDO::PARAM_INT);
        $stmt->execute();
        $rows = $stmt->fetchAll();
        foreach ($rows as &$r) {
            $r['autocheck'] = $r['autocheck_json'] !== null ? json_decode($r['autocheck_json'], true) : null;
            unset($r['autocheck_json']);
        }
        return $rows;
    }

    /**
     * Per-step note count for every step that has at least one row for the site.
     * Drives the "Previous notes (N)" disclosure on each step card.
     * @return array<string, int> step_id => count
     */
    public static function stepCountsForSite(string $siteKey, ?string $excludeId = null): array {
        $sql = 'SELECT s.step_id, COUNT(*) AS c
            FROM step_updates s
            JOIN healthchecks h ON h.id = s.healthcheck_id
            WHERE h.site_key = ?';
        $params = [$siteKey];
        if ($excludeId !== null && $excludeId !== '') {
            $sql .= ' AND h.id != ?';
            $params[] = $excludeId;
        }
        $sql .= ' GROUP BY s.step_id';
        $stmt = Db::pdo()->prepare($sql);
        $stmt->execute($params);
        $out = [];
        foreach ($stmt->fetchAll() as $row) {
            $out[(string) $row['step_id']] = (int) $row['c'];
        }
        return $out;
    }

    /** @return array<int, string> */
    public static function recentSiteKeys(int $limit = 20): array {
        $stmt = Db::pdo()->prepare('SELECT site_key, MAX(updated_at) AS last_seen
            FROM healthchecks GROUP BY site_key ORDER BY last_seen DESC LIMIT ?');
        $stmt->bindValue(1, $limit, \PDO::PARAM_INT);
        $stmt->execute();
        $rows = $stmt->fetchAll();
        return array_map(static fn($r) => ['site_key' => $r['site_key'], 'last_seen' => (int) $r['last_seen']], $rows);
    }

    /**
     * Summary of all sites for the dashboard: one row per site_key,
     * ordered by most-recently-active first.
     * `next_due` is taken from the most recent session, not from the most recent
     * session that happens to have one set. If the latest visit didn't schedule a
     * return, the site genuinely has nothing scheduled — carrying an older date
     * forward would show a visit as overdue immediately after it was completed.
     *
     * @return array<int, array{site_key:string, total:int, finished:int, last_started_at:int, last_finished_at:int|null, last_reporting_url:string, next_due:string|null}>
     */
    public static function allSitesSummary(): array {
        $stmt = Db::pdo()->query(
            'SELECT
                site_key,
                COUNT(*)                                        AS total,
                SUM(CASE WHEN finished_at IS NOT NULL THEN 1 ELSE 0 END) AS finished,
                MAX(started_at)                                 AS last_started_at
             FROM healthchecks
             GROUP BY site_key
             ORDER BY MAX(updated_at) DESC'
        );
        $rows = $stmt->fetchAll();
        // Fetch the reporting_url and finished_at from the most recent session per site.
        $out = [];
        foreach ($rows as $r) {
            $detail = Db::pdo()->prepare(
                'SELECT reporting_url, finished_at, next_due FROM healthchecks
                 WHERE site_key = ? ORDER BY started_at DESC LIMIT 1'
            );
            $detail->execute([$r['site_key']]);
            $last = $detail->fetch() ?: [];
            $out[] = [
                'site_key'         => (string) $r['site_key'],
                'total'            => (int) $r['total'],
                'finished'         => (int) $r['finished'],
                'last_started_at'  => (int) $r['last_started_at'],
                'last_finished_at' => isset($last['finished_at']) && $last['finished_at'] !== null ? (int) $last['finished_at'] : null,
                'last_reporting_url' => (string) ($last['reporting_url'] ?? ''),
                'next_due'         => isset($last['next_due']) && $last['next_due'] !== null && $last['next_due'] !== ''
                    ? (string) $last['next_due']
                    : null,
            ];
        }
        return $out;
    }
}