<?php

namespace Controllers;

use Carbon\Carbon;
use Carbon\Exceptions\InvalidFormatException;
use Exceptions\InvalidTaskDateException;
use Exceptions\TaskNotFoundException;
use Models\Task;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use Repositories\TaskRepository;
use Utils\Enums\TaskStatus;
use Utils\StructuredResponseBuilder;

class TaskController
{

    private $repository, $builder;

    // instead of requesting the builder here, we could simply make it static
    public function __construct(TaskRepository $taskRepository, StructuredResponseBuilder $builder)
    {
        $this->repository = $taskRepository;
        $this->builder = $builder;
    }


    // response is immutable. psr-7 impl makes copies of stuff.
    // TODO: There's a LOT of validation here. We need to build a validator, use a library, or refactor this method.
    public function addTask(ServerRequestInterface $request, ResponseInterface $response): ResponseInterface
    {
        $params = $request->getParsedBody();
        $requiredKeys = ['name', 'description', 'status', 'start', 'end'];


        if (!array_key_exists('tasks', $params)) {
            $this->builder->setError();
            $this->builder->setErrorMessage('Malformed request payload. Please try again.');
            $this->builder->setErrorCode(400);

            $errorResponse = $response->withStatus(400, 'Invalid payload')->withHeader('Content-Type', 'application/json');
            $errorResponse->getBody()->write($this->builder->build());

            return $errorResponse;
        }

        $missingKeys = [];
        foreach ($requiredKeys as $key)
        {
            if (!array_key_exists($key, $params['tasks'])) {
                $missingKeys[] = $key;
            }
        }

        if (!empty($missingKeys)) {
            $this->builder->setError();
            $this->builder->setErrorMessage("The following parameters are missing: " . implode(', ', $missingKeys));
            $this->builder->setErrorCode(400);

            $errorResponse = $response->withStatus('400', 'Missing arguments')->withHeader('Content-Type', 'application/json');
            $errorResponse->getBody()->write($this->builder->build());

            return $errorResponse;
        }

        try
        {
            $start = Carbon::parse($params['tasks']['start']);
            $end = Carbon::parse($params['tasks']['end']);

            if ($start->gt($end) || $end->lt($start)) {
                throw new InvalidTaskDateException('Invalid task date. Start date must not be after end date.');
            }

        } catch (InvalidFormatException | \DomainException $exception)
        {
            $this->builder->setError();
            $this->builder->setErrorMessage($exception->getMessage());
            $this->builder->setErrorCode(400);

            $errorResponse = $response->withStatus(400)->withHeader('Content-Type', 'application/json');
            $errorResponse->getBody()->write($this->builder->build());

            return $errorResponse;
        }

        if (is_null(TaskStatus::tryFrom($params['tasks']['status']))) {
            $this->builder->setError();
            $this->builder->setErrorCode(400);
            $this->builder->setErrorMessage('Invalid task status code. Status must range from 1-4 (started, in progress, blocked, completed).');

            $errorResponse = $response->withStatus(400)->withHeader('Content-Type', 'application/json');
            $errorResponse->getBody()->write($this->builder->build());

            return $errorResponse;
        }

        $task = new Task();
        $task->setName($params['tasks']['name'])
            ->setStatusId(TaskStatus::tryFrom((int) $params['tasks']['status']))
            ->setDescription($params['tasks']['description'])
            ->setStart($params['tasks']['start'])
            ->setEnd($params['tasks']['end']);


        $createdTask = $this->repository->create($task);
        if ($createdTask == 0)
        {
            $this->builder->setError()
                ->setErrorMessage('An unexpected error has occurred whilst trying to perform this operation.')
                ->setErrorCode(500);

            $errorResponse = $response->withStatus(500)->withHeader('Content-Type', 'application/json');
            $errorResponse->getBody()->write($this->builder->build());

            return $errorResponse;
        }

        $createdResponse = $response->withStatus(201)->withHeader('Content-Type', 'application/json');
        $this->builder->setOptionalMessage('Task created.')
            ->setPayload($task->setId($createdTask)->persist());

        $createdResponse->getBody()->write($this->builder->build());
        return $createdResponse;
    }

    public function getTasks(ServerRequestInterface $request, ResponseInterface $response): ResponseInterface
    {
        $tasks = $this->repository->readAll();
        $payload['tasks'] = $tasks;

        $this->builder->setPayload($payload)->setOptionalMessage('Listing all tasks: ');
        $response->getBody()->write($this->builder->build());

        return $response;
    }

    public function getTask(ServerRequestInterface $request, ResponseInterface $response, string $id): ResponseInterface
    {
        try {
            $payload['task'] = $this->repository->readById((int)$id)->persist();

            $this->builder->setPayload($payload)->setOptionalMessage("Task retrieved.");
            $response->getBody()->write($this->builder->build());

            return $response;

        } catch (TaskNotFoundException $e) {

            $this->builder->setError()->setErrorMessage($e->getMessage())->setErrorCode(404);
            $errorResponse = $response->withStatus(404, $e->getMessage());

            $response->getBody()->write($this->builder->build());
            return $errorResponse;
        }
    }

    public function delete(ServerRequestInterface $request, ResponseInterface $response, $id): ResponseInterface
    {
        try
        {
            $task = $this->repository->readById((int) $id);
            $this->repository->delete($task);

            $this->builder->setOptionalMessage('Task deleted.');
            $response->getBody()->write($this->builder->build());

            return $response;

        } catch (TaskNotFoundException $exception)
        {
            $this->builder->setError()->setErrorMessage($exception->getMessage())->setErrorCode(404);

            $errorResponse = $response->withStatus(404);
            $errorResponse->getBody()->write($this->builder->build());

            return $errorResponse;
        }
    }


    public function update(ServerRequestInterface $request, ResponseInterface $response, $id): ResponseInterface
    {
        $payloadWarnings = [];

        $toUpdate = $request->getParsedBody()['payload']['update'];
        $toUpdate['updated_at'] = Carbon::now()->toDateTimeString();

        $acceptableFields = [
          'task_owner',
          'name',
          'description',
          'start',
          'end'
        ];

        foreach ($toUpdate as $updateField => $value)
        {
            if($updateField !== 'updated_at' && !in_array($updateField, $acceptableFields))
            {
                $payloadWarnings[] = "W: An invalid, unknown, or locked field has been truncated: " . $updateField;
                unset($toUpdate[$updateField]);
            }
        }

        try
        {
            $task = $this->repository->readById($id);
            // if we used the dirty implementation, we could skip all this code

            foreach($toUpdate as $property => $value)
            {
                // ignore updated_at
                if($property !== 'updated_at')
                {
                    $task->{'set' . ucfirst(snakeToCamel($property))}($value);
                }
            }

            $finalFields = array_keys($toUpdate);
            $result = $this->repository->updateSelective($task, $finalFields);

            if ($result && empty($payloadWarnings))
            {
                return $response->withStatus(204);
            }
            elseif($result)
            {
                $this->builder->setOptionalMessage('Task updated successfully with warnings.')
                    ->setPayload([
                        'updated' => $toUpdate,
                        'warnings' => $payloadWarnings,
                    ]);
                $response->getBody()->write($this->builder->build());

                return $response;
            }
            else
            {
                $this->builder->setError()
                    ->setErrorMessage('An unexpected error occurred while updating the resource.')
                    ->setErrorCode(500);

                $errorResponse = $response->withStatus(500)->withHeader('Content-Type', 'application/json');
                $errorResponse->getBody()->write($this->builder->build());

                return $errorResponse;
            }

        }
        catch (TaskNotFoundException $e)
        {
            $this->builder->setError()
                ->setErrorMessage($e->getMessage())
                ->setErrorCode(404);

            $errorResponse = $response->withStatus(404)->withHeader('Content-Type', 'application/json');
            $errorResponse->getBody()->write($this->builder->build());

            return $errorResponse;
        }
    }
}