<?php

declare(strict_types=1);

namespace App\Services\TenantConfiguration;

use App\Support\Providers\ProviderReasonCodes;
use Throwable;

final class ExchangePowerShellRuntimeReadinessChecker
{
    public function __construct(
        private readonly ExchangePowerShellProcessExecutor $executor,
    ) {}

    public function check(?ExchangePowerShellRuntimePolicy $policy = null): ExchangePowerShellGateResult
    {
        $policy ??= ExchangePowerShellRuntimePolicy::fromConfig();

        try {
            if (! $policy->invocationEnabled) {
                return $this->blocked('runtime_blocked_feature_disabled', [
                    'runtime_state' => 'blocked_feature_disabled',
                ]);
            }

            if (! $policy->productionRunnerEnabled) {
                return $this->blocked('runtime_blocked_runner_disabled', [
                    'runtime_state' => 'blocked_runner_disabled',
                ]);
            }

            if (! $policy->environmentAllowed()) {
                return $this->blocked('runtime_blocked_environment_not_allowed', [
                    'runtime_state' => 'environment_not_allowed',
                    'runtime_environment' => $policy->currentEnvironment,
                ]);
            }

            if (! $policy->timeoutPolicyValid()) {
                return $this->blocked('runtime_blocked_timeout_policy_missing', [
                    'runtime_state' => 'timeout_policy_missing',
                ]);
            }

            if (! $policy->tempPolicySafe()) {
                return $this->blocked('runtime_blocked_temp_policy_unsafe', [
                    'runtime_state' => 'temp_policy_unsafe',
                ]);
            }

            if (! $this->executor->available()) {
                return $this->blocked('runtime_blocked_process_executor_missing', [
                    'runtime_state' => 'process_executor_missing',
                ]);
            }

            $powershell = $this->executor->run(new ExchangePowerShellProcessCommand(
                arguments: [
                    $policy->powershellBinary,
                    '-NoLogo',
                    '-NoProfile',
                    '-NonInteractive',
                    '-Command',
                    '$PSVersionTable.PSVersion.ToString()',
                ],
                timeoutSeconds: $policy->checkTimeoutSeconds,
                stdoutMaxBytes: 4096,
                stderrMaxBytes: 4096,
            ));

            if ($powershell->timedOut || $powershell->exitCode !== 0 || trim($powershell->stdout) === '') {
                return $this->blocked('runtime_blocked_powershell_missing', [
                    'runtime_state' => 'powershell_missing',
                ]);
            }

            if (! $policy->moduleCheckEnabled) {
                return ExchangePowerShellGateResult::allowed([
                    'runtime_state' => 'ready',
                    'module_state' => 'unchecked',
                ]);
            }

            $module = $this->executor->run(new ExchangePowerShellProcessCommand(
                arguments: [
                    $policy->powershellBinary,
                    '-NoLogo',
                    '-NoProfile',
                    '-NonInteractive',
                    '-Command',
                    'Get-Module -ListAvailable -Name ExchangeOnlineManagement',
                ],
                timeoutSeconds: $policy->checkTimeoutSeconds,
                stdoutMaxBytes: 4096,
                stderrMaxBytes: 4096,
            ));

            if ($module->timedOut || $module->exitCode !== 0) {
                return $this->blocked('runtime_blocked_exchange_module_unknown', [
                    'runtime_state' => 'exchange_module_unknown',
                ]);
            }

            if (! str_contains(trim($module->stdout), 'ExchangeOnlineManagement')) {
                return $this->blocked('runtime_blocked_exchange_module_missing', [
                    'runtime_state' => 'exchange_module_missing',
                ]);
            }

            return ExchangePowerShellGateResult::allowed([
                'runtime_state' => 'ready',
                'module_state' => 'available',
            ]);
        } catch (Throwable) {
            return ExchangePowerShellGateResult::blocked(
                reasonCode: ProviderReasonCodes::UnknownError,
                failureCode: 'runtime_failed_unexpected',
                message: 'Exchange PowerShell runtime readiness failed safely.',
                context: ['runtime_state' => 'unexpected_failure'],
            );
        }
    }

    /**
     * @param  array<string, mixed>  $context
     */
    private function blocked(string $failureCode, array $context): ExchangePowerShellGateResult
    {
        return ExchangePowerShellGateResult::blocked(
            reasonCode: ProviderReasonCodes::ProviderBindingUnsupported,
            failureCode: $failureCode,
            message: 'Exchange PowerShell runtime readiness is not satisfied.',
            context: $context,
        );
    }
}