<?php

namespace Tests\Unit\Services;

use App\Models\Setting;
use App\Services\Invoice;
use Illuminate\Foundation\Testing\DatabaseTransactions;
use Illuminate\Support\Facades\DB;
use Tests\TestCase;

/**
 * Unit tests for Invoice Service
 */
class InvoiceServiceTest extends TestCase
{
    use DatabaseTransactions;

    protected function setUp(): void
    {
        parent::setUp();

        // Ensure clean state
        Setting::where('slug', 'invoice-number')->delete();
    }

    /**
     * Test invoice number retrieval
     *
     * @test
     */
    public function it_gets_current_invoice_number()
    {
        Setting::create([
            'slug' => 'invoice-number',
            'type' => 'int',
            'int' => 12345,
        ]);

        $number = Invoice::getInvoiceNumber();

        $this->assertEquals(12345, $number);
    }

    /**
     * Test invoice number increment
     *
     * @test
     */
    public function it_increments_invoice_number()
    {
        Setting::create([
            'slug' => 'invoice-number',
            'type' => 'int',
            'int' => 100,
        ]);

        $newNumber = Invoice::makeNextInvoiceNumber();

        $this->assertEquals(101, $newNumber);

        // Verify it was persisted
        $storedNumber = Invoice::getInvoiceNumber();
        $this->assertEquals(101, $storedNumber);
    }

    /**
     * Test multiple sequential increments
     *
     * @test
     */
    public function it_increments_sequentially()
    {
        Setting::create([
            'slug' => 'invoice-number',
            'type' => 'int',
            'int' => 1,
        ]);

        $numbers = [];
        for ($i = 0; $i < 5; $i++) {
            $numbers[] = Invoice::makeNextInvoiceNumber();
        }

        $this->assertEquals([2, 3, 4, 5, 6], $numbers);
    }

    /**
     * Test invoice number format with year prefix
     *
     * @test
     */
    public function it_formats_invoice_number_with_year_prefix()
    {
        $formatted = Invoice::createInvoiceNumber(123, '15.06.2024');
        $this->assertEquals('202400123', $formatted);

        $formatted = Invoice::createInvoiceNumber(1, '01.01.2025');
        $this->assertEquals('202500001', $formatted);

        $formatted = Invoice::createInvoiceNumber(99999, '31.12.2026');
        $this->assertEquals('202699999', $formatted);
    }

    /**
     * Test invoice storage directory path
     *
     * @test
     */
    public function it_generates_correct_storage_paths()
    {
        $path = Invoice::getInvoiceStorageDir('15.06.2024');
        $this->assertEquals('invoice/2024/06/', $path);

        $path = Invoice::getDeliveryStorageDir('01.01.2025');
        $this->assertEquals('delivery/2025/01/', $path);
    }

    /**
     * Test invoice filename generation
     *
     * @test
     */
    public function it_generates_correct_filenames()
    {
        $filename = Invoice::makeInvoiceFilename('202400123');
        $this->assertEquals('202400123-MIVITA-Rechnung.pdf', $filename);

        $filename = Invoice::makeDeliveryFilename('202400123');
        $this->assertEquals('202400123-MIVITA-Lieferschein.pdf', $filename);
    }

    /**
     * Test invoice number initialization when not exists
     *
     * @test
     */
    public function it_initializes_invoice_number_when_not_exists()
    {
        // Make sure it doesn't exist
        Setting::where('slug', 'invoice-number')->delete();

        $number = Invoice::makeNextInvoiceNumber();

        $this->assertEquals(1, $number);

        // Verify setting was created
        $setting = Setting::where('slug', 'invoice-number')->first();
        $this->assertNotNull($setting);
        $this->assertEquals('int', $setting->type);
        $this->assertEquals(1, $setting->int);
    }

    /**
     * Test invoice number atomicity with explicit transaction
     *
     * @test
     */
    public function it_uses_transaction_for_invoice_number_increment()
    {
        Setting::create([
            'slug' => 'invoice-number',
            'type' => 'int',
            'int' => 500,
        ]);

        // makeNextInvoiceNumber includes its own transaction
        $number = Invoice::makeNextInvoiceNumber();

        $this->assertEquals(501, $number);

        // Can be called within another transaction
        DB::transaction(function () {
            $number = Invoice::makeNextInvoiceNumber();
            $this->assertEquals(502, $number);
        });

        $finalNumber = Invoice::getInvoiceNumber();
        $this->assertEquals(502, $finalNumber);
    }

    /**
     * Test invoice number with database lock
     *
     * @test
     */
    public function it_locks_setting_during_increment()
    {
        Setting::create([
            'slug' => 'invoice-number',
            'type' => 'int',
            'int' => 1000,
        ]);

        // Verify the lock mechanism works
        DB::transaction(function () {
            $setting = Setting::where('slug', 'invoice-number')
                ->lockForUpdate()
                ->first();

            $this->assertNotNull($setting);
            $this->assertEquals(1000, $setting->int);
        });
    }

    /**
     * Test invoice number padding
     *
     * @test
     */
    public function it_pads_invoice_numbers_correctly()
    {
        $tests = [
            [1, '202400001'],
            [12, '202400012'],
            [123, '202400123'],
            [1234, '202401234'],
            [12345, '202412345'],
        ];

        foreach ($tests as [$number, $expected]) {
            $formatted = Invoice::createInvoiceNumber($number, '01.01.2024');
            $this->assertEquals($expected, $formatted);
        }
    }

    /**
     * Test getInvoiceNumber returns 0 when setting doesn't exist
     *
     * @test
     */
    public function it_returns_zero_when_invoice_number_not_set()
    {
        Setting::where('slug', 'invoice-number')->delete();

        $number = Invoice::getInvoiceNumber();

        $this->assertEquals(0, $number);
    }

    /**
     * Test concurrent increment simulation
     *
     * @test
     */
    public function it_handles_rapid_increments_without_gaps()
    {
        Setting::create([
            'slug' => 'invoice-number',
            'type' => 'int',
            'int' => 7000,
        ]);

        $numbers = [];
        $iterations = 15;

        for ($i = 0; $i < $iterations; $i++) {
            $numbers[] = Invoice::makeNextInvoiceNumber();
        }

        // Check for uniqueness
        $unique = array_unique($numbers);
        $this->assertCount($iterations, $unique, 'All numbers must be unique');

        // Check for no gaps
        sort($numbers);
        for ($i = 0; $i < $iterations; $i++) {
            $expected = 7001 + $i;
            $this->assertEquals($expected, $numbers[$i], 'No gaps allowed in sequence');
        }
    }

    /**
     * Test invoice number type casting
     *
     * @test
     */
    public function it_returns_integer_invoice_number()
    {
        Setting::create([
            'slug' => 'invoice-number',
            'type' => 'int',
            'int' => 999,
        ]);

        $number = Invoice::getInvoiceNumber();

        $this->assertIsInt($number);
        $this->assertEquals(999, $number);
    }
}