<?php

if (!defined('ABSPATH')) {
    exit;
}

/**
 * Admin-list view snapshot caching: a `wp_abj404_view_cache` table holds JSON
 * payloads for the admin list/count views so a fast first paint is possible
 * without waiting on the heavy aggregate queries. This trait owns the
 * lifecycle: table DDL, refresh-lock dance (option-based, cooldown-bounded),
 * snapshot read/write/wait, and stale-row cleanup. Constants
 * (`VIEW_SNAPSHOT_*`) and the request-local "DDL ensured" flag remain on the
 * using class because tests reset them via the public static accessor.
 */
trait ABJ_404_Solution_DataAccess_ViewSnapshotCacheTrait {

    /**
     * Build a stable cache key for admin list data/count snapshots.
     *
     * @param string $prefix
     * @param string $sub
     * @param array<string, mixed> $tableOptions
     * @return string
     */
    private function getViewSnapshotCacheKey($prefix, $sub, $tableOptions) {
        $cacheShape = array(
            'sub' => (string)$sub,
            'filter' => is_scalar($tableOptions['filter'] ?? 0) ? (int)($tableOptions['filter'] ?? 0) : 0,
            'orderby' => is_scalar($tableOptions['orderby'] ?? 'url') ? (string)($tableOptions['orderby'] ?? 'url') : 'url',
            'order' => is_scalar($tableOptions['order'] ?? 'ASC') ? (string)($tableOptions['order'] ?? 'ASC') : 'ASC',
            'paged' => is_scalar($tableOptions['paged'] ?? 1) ? (int)($tableOptions['paged'] ?? 1) : 1,
            'perpage' => is_scalar($tableOptions['perpage'] ?? ABJ404_OPTION_DEFAULT_PERPAGE) ? (int)($tableOptions['perpage'] ?? ABJ404_OPTION_DEFAULT_PERPAGE) : ABJ404_OPTION_DEFAULT_PERPAGE,
            'filterText' => is_scalar($tableOptions['filterText'] ?? '') ? (string)($tableOptions['filterText'] ?? '') : '',
            'score_range' => (function ($v) { return is_string($v) ? $v : 'all'; })($tableOptions['score_range'] ?? 'all'),
            'blog' => function_exists('get_current_blog_id') ? (int)get_current_blog_id() : 1,
        );
        $encoded = function_exists('wp_json_encode') ? wp_json_encode($cacheShape) : json_encode($cacheShape);
        return $prefix . '_' . md5((string)$encoded);
    }

    /** @return void */
    private function ensureViewSnapshotTableExists(): void {
        if (self::$viewSnapshotTableEnsured) {
            return;
        }
        self::$viewSnapshotTableEnsured = true;
        $sqlFile = __DIR__ . '/sql/createViewCacheTable.sql';
        $create = ABJ_404_Solution_Functions::readFileContents($sqlFile);
        if (is_string($create) && trim($create) !== '') {
            $this->queryAndGetResults($create, array('log_errors' => false));
        }
    }

    /** @param string $cacheKey @return string */
    private function getViewSnapshotLockOptionName(string $cacheKey): string {
        return $this->getLowercasePrefix() . 'abj404_view_cache_lock_' . md5((string)$cacheKey);
    }

    /** @param string $cacheKey @return bool */
    private function isViewSnapshotRefreshLocked(string $cacheKey): bool {
        if (!function_exists('get_option')) {
            return false;
        }
        $lockKey = $this->getViewSnapshotLockOptionName($cacheKey);
        $lockValue = get_option($lockKey, false);
        if ($lockValue === false || $lockValue === '' || $lockValue === null) {
            return false;
        }
        $lockTs = is_numeric($lockValue) ? (int)$lockValue : 0;
        if ($lockTs > 0 && (time() - $lockTs) > self::VIEW_SNAPSHOT_REFRESH_COOLDOWN_SECONDS) {
            if (function_exists('delete_option')) {
                delete_option($lockKey);
            }
            return false;
        }
        return true;
    }

    /** @param string $cacheKey @return bool */
    private function acquireViewSnapshotRefreshLock(string $cacheKey): bool {
        if (!function_exists('add_option')) {
            return true;
        }
        if ($this->isViewSnapshotRefreshLocked($cacheKey)) {
            return false;
        }
        $lockKey = $this->getViewSnapshotLockOptionName($cacheKey);
        return (bool)add_option($lockKey, time(), '', false);
    }

    /** @param string $cacheKey @return void */
    private function releaseViewSnapshotRefreshLock(string $cacheKey): void {
        if (function_exists('delete_option')) {
            delete_option($this->getViewSnapshotLockOptionName($cacheKey));
        }
    }

    /**
     * @param mixed $payload
     * @return array<string, mixed>|null
     */
    private function decodeSnapshotPayload($payload) {
        if (!is_string($payload) || $payload === '') {
            return null;
        }
        $decoded = json_decode($payload, true);
        return is_array($decoded) ? $decoded : null;
    }

    /**
     * @param string $cacheKey
     * @param bool $allowExpired
     * @param bool $respectCooldown
     * @return array<string, mixed>|null
     */
    private function getViewRowsSnapshotFromTable(string $cacheKey, bool $allowExpired = false, bool $respectCooldown = false) {
        $this->ensureViewSnapshotTableExists();
        $query = "SELECT payload, refreshed_at, expires_at
            FROM {wp_abj404_view_cache}
            WHERE cache_key = %s LIMIT 1";
        $result = $this->queryAndGetResults($query, array('query_params' => array($cacheKey), 'log_errors' => false));
        if (!is_array($result['rows']) || empty($result['rows']) || !is_array($result['rows'][0])) {
            return null;
        }
        $row = $result['rows'][0];
        $expiresAt = intval($row['expires_at'] ?? 0);
        $refreshedAt = intval($row['refreshed_at'] ?? 0);
        $now = time();
        $isFresh = ($expiresAt > $now);
        $recentEnough = ($refreshedAt > 0 && ($now - $refreshedAt) <= self::VIEW_SNAPSHOT_REFRESH_COOLDOWN_SECONDS);
        if (!$allowExpired && !$isFresh) {
            return null;
        }
        if ($respectCooldown && !$isFresh && !$recentEnough) {
            return null;
        }
        return $this->decodeSnapshotPayload((string)($row['payload'] ?? ''));
    }

    /**
     * @param string $cacheKey
     * @param string $sub
     * @param mixed $rows
     * @param int $ttlSeconds
     * @return void
     */
    private function setViewRowsSnapshotToTable(string $cacheKey, string $sub, $rows, int $ttlSeconds): void {
        if (!is_array($rows)) {
            return;
        }
        $this->ensureViewSnapshotTableExists();
        $encoded = function_exists('wp_json_encode') ? wp_json_encode($rows) : json_encode($rows);
        if (!is_string($encoded)) {
            return;
        }
        $bytes = strlen($encoded);
        if ($bytes > self::VIEW_SNAPSHOT_MAX_PAYLOAD_BYTES) {
            return;
        }
        $now = time();
        $expiresAt = $now + max(1, intval($ttlSeconds));
        $query = "INSERT INTO {wp_abj404_view_cache}
            (cache_key, subpage, payload, payload_bytes, refreshed_at, expires_at, updated_at)
            VALUES (%s, %s, %s, %d, %d, %d, %d)
            ON DUPLICATE KEY UPDATE
                subpage = VALUES(subpage),
                payload = VALUES(payload),
                payload_bytes = VALUES(payload_bytes),
                refreshed_at = VALUES(refreshed_at),
                expires_at = VALUES(expires_at),
                updated_at = VALUES(updated_at)";
        $this->queryAndGetResults($query, array(
            'query_params' => array($cacheKey, (string)$sub, $encoded, $bytes, $now, $expiresAt, $now),
            'log_errors' => false,
        ));
        $this->cleanupExpiredViewSnapshotRowsIfNeeded();
    }

    /**
     * @param string $cacheKey
     * @param int $timeoutMs
     * @return array<string, mixed>|null
     */
    private function waitForViewRowsSnapshotFromTable(string $cacheKey, int $timeoutMs = 4000) {
        $deadline = microtime(true) + (max(100, intval($timeoutMs)) / 1000);
        while (microtime(true) < $deadline) {
            $rows = $this->getViewRowsSnapshotFromTable($cacheKey, false, false);
            if (is_array($rows)) {
                return $rows;
            }
            usleep(100000);
        }
        return null;
    }

    /** @return void */
    private function cleanupExpiredViewSnapshotRowsIfNeeded(): void {
        if (!function_exists('get_transient') || !function_exists('set_transient')) {
            return;
        }
        $marker = get_transient('abj404_view_cache_cleanup_marker');
        if ($marker !== false) {
            return;
        }
        set_transient('abj404_view_cache_cleanup_marker', time(), 1800);
        $query = "DELETE FROM {wp_abj404_view_cache} WHERE expires_at < %d";
        $this->queryAndGetResults($query, array(
            'query_params' => array(time() - self::VIEW_SNAPSHOT_REFRESH_COOLDOWN_SECONDS),
            'log_errors' => false,
        ));
    }
}