<?php

namespace MathPHP\Tests\LinearAlgebra;

use MathPHP\LinearAlgebra\Vector;
use MathPHP\Exception;

class VectorInterfaceTest extends \PHPUnit\Framework\TestCase
{
    /** @var array */
    private $A;

    /** @var Vector */
    private $V;

    public function setUp()
    {
        // Given
        $this->A = [1, 2, 3, 4, 5];
        $this->V = new Vector($this->A);
    }

    /**
     * @test Interfaces
     */
    public function testInterfaces()
    {
        // Given
        $interfaces = class_implements('\MathPHP\LinearAlgebra\Vector');

        // Then
        $this->assertContains('Countable', $interfaces);
        $this->assertContains('ArrayAccess', $interfaces);
        $this->assertContains('JsonSerializable', $interfaces);
    }

    /**
     * @test ArrayAccess interface
     */
    public function testArrayAccessInterfaceOffsetGet()
    {
        // Then
        $this->assertEquals(1, $this->V[0]);
        $this->assertEquals(2, $this->V[1]);
        $this->assertEquals(3, $this->V[2]);
        $this->assertEquals(4, $this->V[3]);
        $this->assertEquals(5, $this->V[4]);
    }

    /**
     * @test ArrayAccess interface
     */
    public function testArrayAccessInterfaceOffsetSet()
    {
        // Then
        $this->expectException(Exception\VectorException::class);

        // When
        $this->V[0] = 1;
    }

    /**
     * @test ArrayAccess interface
     */
    public function testArrayAccessOffsetExists()
    {
        // Then
        $this->assertTrue($this->V->offsetExists(0));
    }

    /**
     * @test ArrayAccess interface
     */
    public function testArrayAccessOffsetUnsetException()
    {
        // Then
        $this->expectException(Exception\VectorException::class);

        // When
        unset($this->V[0]);
    }

    /**
     * @test         Countable interface
     * @dataProvider dataProviderForCountable
     * @param        array $A
     * @param        int $n
     */
    public function testCountableInterface(array $A, int $n)
    {
        // Given
        $V = new Vector($A);

        // When
        $count = count($V);

        // Then
        $this->assertEquals($n, $count);
    }

    public function dataProviderForCountable(): array
    {
        return [
            [[1], 1],
            [[1, 1], 2],
            [[1, 1, 1], 3],
            [[1, 1, 1, 1], 4],
            [[1, 1, 1, 1, 1], 5],
            [[1, 1, 1, 1, 1, 1], 6],
            [[1, 1, 1, 1, 1, 1, 1], 7],
            [[1, 1, 1, 1, 1, 1, 1, 1], 8],
            [[1, 1, 1, 1, 1, 1, 1, 1, 1], 9],
            [[1, 1, 1, 1, 1, 1, 1, 1, 1, 1], 10],
        ];
    }

    /**
     * @test         JsonSerializable interface
     * @dataProvider dataProviderForJsonSerializable
     * @param        array $A
     * @param        string $json
     */
    public function testJsonSerializable(array $A, string $json)
    {
        // Given
        $A = new Vector($A);

        // When
        $jsonString = json_encode($A);

        // Then
        $this->assertEquals($json, $jsonString);
    }

    public function dataProviderForJsonSerializable(): array
    {
        return [
            [
                [1],
                '[1]',
            ],
            [
                [1, 2, 3],
                '[1,2,3]',
            ],
        ];
    }

    /**
     * @test Iteration
     */
    public function testIteration()
    {
        // When
        foreach ($this->V as $element) {
            // Then
            $this->assertTrue(is_int($element));
        }

        // When Rewinding
        foreach ($this->V as $element) {
            // Then
            $this->assertTrue(is_int($element));
        }
    }

    public function testIteratorKeys()
    {
        // When
        foreach ($this->V as $k => $v) {
            // Then
            $this->assertSame($v, $this->A[$k]);
        }
    }
}