<?php

use GuzzleHttp\Client;
use GuzzleHttp\Handler\MockHandler;
use GuzzleHttp\HandlerStack;
use GuzzleHttp\Middleware;
use GuzzleHttp\Psr7\HttpFactory;
use GuzzleHttp\Psr7\Response;
use Laya\Exception\UnexpectedResponseException;
use Laya\Laya;
use Laya\LayaClient;
use Laya\Question\QuestionSet;
use Laya\Question\YesNoQuestion;

/** @return array{LayaClient, ArrayObject} client and the recorded request history */
function fakeClient(array $responses): array
{
    $history = new ArrayObject();
    $stack = HandlerStack::create(new MockHandler($responses));
    $stack->push(Middleware::history($history));
    $factory = new HttpFactory();

    return [new LayaClient(new Client(['handler' => $stack]), $factory, $factory, 'http://laya.test'), $history];
}

function json(array $body, int $status = 200): Response
{
    return new Response($status, ['Content-Type' => 'application/json'], json_encode($body));
}

function questions(): QuestionSet
{
    return QuestionSet::make()->add(new YesNoQuestion('angry', 'Upset?'));
}

it('posts the state and questions to /predict', function () {
    [$client, $history] = fakeClient([json(['answers' => ['angry' => ['type' => 'noul', 'noul' => 0.8]]])]);

    $result = $client->decide('hello', questions());

    $request = $history[0]['request'];
    expect($request->getMethod())->toBe('POST')
        ->and((string) $request->getUri())->toBe('http://laya.test/predict')
        ->and($request->getHeaderLine('Content-Type'))->toBe('application/json')
        ->and($request->getHeaderLine('Accept'))->toBe('application/json')
        ->and(json_decode((string) $request->getBody(), true))->toBe([
            'state' => ['body' => 'hello'],
            'questions' => ['angry' => ['type' => 'noul', 'instructions' => 'Upset?']],
        ])
        ->and($result->get('angry')->probability())->toBe(0.8);
});

it('sends an array state unchanged and includes the model when given', function () {
    [$client, $history] = fakeClient([json(['answers' => []])]);

    $client->decide(['subject' => 's', 'body' => 'b'], questions(), 'my-model');

    $sent = json_decode((string) $history[0]['request']->getBody(), true);
    expect($sent['state'])->toBe(['subject' => 's', 'body' => 'b'])
        ->and($sent['model'])->toBe('my-model');
});

it('omits model when none is given', function () {
    [$client, $history] = fakeClient([json(['answers' => []])]);

    $client->decide('x', questions());

    expect(json_decode((string) $history[0]['request']->getBody(), true))->not->toHaveKey('model');
});

it('gets /models', function () {
    [$client, $history] = fakeClient([json(['models' => ['a', 'b']])]);

    expect($client->models())->toBe(['models' => ['a', 'b']])
        ->and($history[0]['request']->getMethod())->toBe('GET')
        ->and((string) $history[0]['request']->getUri())->toBe('http://laya.test/models');
});

it('throws UnexpectedResponseException with the server detail on HTTP errors', function () {
    [$client] = fakeClient([json(['detail' => 'bad model'], 422)]);

    try {
        $client->decide('x', questions());
        $this->fail('expected exception');
    } catch (UnexpectedResponseException $e) {
        expect($e->statusCode())->toBe(422)
            ->and($e->getMessage())->toBe('Laya returned HTTP 422: bad model');
    }
});

it('throws JsonException when the body is not JSON', function () {
    [$client] = fakeClient([new Response(200, [], 'not json')]);

    $client->models();
})->throws(JsonException::class);

it('builds a client through discovery', function () {
    expect(Laya::client('http://laya.test'))->toBeInstanceOf(LayaClient::class);
});