<?php

namespace classes;

/**
 * Explicit account-deletion schema management.
 *
 * apply() must only be invoked by the dedicated CLI. Web requests and cron jobs
 * are deliberately limited to the read-only check().
 */
class account_deletion_schema_bootstrap
{
    /** @return array{ready:bool,missing:array<int,string>} */
    public static function check(): array
    {
        global $db;
        $missing = [];
        foreach (['account_deletion_requests', 'account_deletion_credential_attempts', 'account_deletion_outbox'] as $table) {
            $tableSql = $db->escape_string($table);
            $result = $db->query("SHOW TABLES LIKE '$tableSql'");
            if ($result === false || $result->num_rows === 0) {
                $missing[] = 'table:' . $table;
            }
        }
        foreach (['users' => 'deleted_at', 'subusers' => 'deleted_at'] as $table => $column) {
            $result = $db->query("SHOW COLUMNS FROM `$table` LIKE '$column'");
            if ($result === false || $result->num_rows === 0) {
                $missing[] = 'column:' . $table . '.' . $column;
            }
        }
        if (!in_array('table:account_deletion_requests', $missing, true)) {
            $result = $db->query("SHOW COLUMNS FROM account_deletion_requests LIKE 'manual_review_required_at'");
            if ($result === false || $result->num_rows === 0) {
                $missing[] = 'column:account_deletion_requests.manual_review_required_at';
            }
        }
        return ['ready' => $missing === [], 'missing' => $missing];
    }

    public static function apply(): void
    {
        if (PHP_SAPI !== 'cli') {
            throw new \RuntimeException('Account deletion schema changes are CLI-only.');
        }
        global $db;
        self::execute("CREATE TABLE IF NOT EXISTS account_deletion_requests (
            id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
            request_id CHAR(36) NOT NULL,
            principal_type VARCHAR(16) NOT NULL,
            principal_id BIGINT UNSIGNED NOT NULL,
            customer_number_snapshot INT NULL,
            active_principal_key VARCHAR(191) NULL,
            status VARCHAR(32) NOT NULL DEFAULT 'requested',
            policy_version VARCHAR(32) NOT NULL,
            retained_data_json LONGTEXT NOT NULL,
            request_ip VARCHAR(45) NULL,
            request_user_agent VARCHAR(512) NULL,
            retry_count INT UNSIGNED NOT NULL DEFAULT 0,
            failure_code VARCHAR(191) NULL,
            requested_at DATETIME NOT NULL,
            processing_at DATETIME NULL,
            completed_at DATETIME NULL,
            next_attempt_at DATETIME NULL,
            manual_review_required_at DATETIME NULL,
            created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
            updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
            PRIMARY KEY (id),
            UNIQUE KEY uniq_account_deletion_request_id (request_id),
            UNIQUE KEY uniq_account_deletion_active_principal (active_principal_key),
            INDEX idx_account_deletion_worker (status, next_attempt_at, requested_at),
            INDEX idx_account_deletion_principal (principal_type, principal_id, requested_at)
        ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci");
        self::ensureColumn('account_deletion_requests', 'manual_review_required_at', 'DATETIME NULL AFTER `next_attempt_at`');
        self::execute("CREATE TABLE IF NOT EXISTS account_deletion_credential_attempts (
            throttle_key CHAR(64) NOT NULL,
            attempt_count INT UNSIGNED NOT NULL DEFAULT 1,
            window_started_at DATETIME NOT NULL,
            blocked_until DATETIME NULL,
            updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
            PRIMARY KEY (throttle_key), INDEX idx_account_deletion_throttle_expiry (updated_at)
        ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci");
        self::execute("CREATE TABLE IF NOT EXISTS account_deletion_outbox (
            id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
            request_id CHAR(36) NOT NULL,
            event_type VARCHAR(64) NOT NULL,
            payload_json LONGTEXT NOT NULL,
            status VARCHAR(16) NOT NULL DEFAULT 'pending',
            attempts INT UNSIGNED NOT NULL DEFAULT 0,
            available_at DATETIME NOT NULL,
            processing_at DATETIME NULL,
            delivered_at DATETIME NULL,
            last_error VARCHAR(191) NULL,
            created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
            PRIMARY KEY (id), UNIQUE KEY uniq_account_deletion_outbox_event (request_id, event_type),
            INDEX idx_account_deletion_outbox_delivery (status, available_at)
        ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci");
        self::ensureColumn('account_deletion_outbox', 'processing_at', 'DATETIME NULL AFTER `available_at`');
        self::ensureColumn('users', 'deleted_at', 'DATETIME NULL AFTER `updated_at`');
        self::ensureColumn('subusers', 'deleted_at', 'DATETIME NULL AFTER `suspended_at`');
        self::ensureIndex('users', 'idx_users_deleted_at', '`deleted_at`');
        self::ensureIndex('subusers', 'idx_subusers_deleted_at', '`deleted_at`');
    }

    private static function execute(string $sql): void
    {
        global $db;
        if ($db->query($sql) === false) {
            throw new \RuntimeException('Account deletion schema operation failed.');
        }
    }

    private static function ensureColumn(string $table, string $column, string $definition): void
    {
        global $db;
        $result = $db->query("SHOW COLUMNS FROM `$table` LIKE '$column'");
        if ($result === false) throw new \RuntimeException('Unable to inspect account deletion schema.');
        if ($result->num_rows === 0) self::execute("ALTER TABLE `$table` ADD COLUMN `$column` $definition");
    }

    private static function ensureIndex(string $table, string $index, string $columns): void
    {
        global $db;
        $result = $db->query("SHOW INDEX FROM `$table` WHERE Key_name = '$index'");
        if ($result === false) throw new \RuntimeException('Unable to inspect account deletion indexes.');
        if ($result->num_rows === 0) self::execute("ALTER TABLE `$table` ADD INDEX `$index` ($columns)");
    }
}