<?php
declare(strict_types=1);

namespace Unsupervised\Schedular\Tests\Unit\Guardian;

use Brain\Monkey\Functions;
use Mockery;
use Unsupervised\Schedular\Booking\BookingRepository;
use Unsupervised\Schedular\GroupClass\EnrollmentRepository;
use Unsupervised\Schedular\Guardian\GuardianLink;
use Unsupervised\Schedular\Guardian\GuardianRepository;
use Unsupervised\Schedular\Guardian\GuardianService;
use Unsupervised\Schedular\Tests\Unit\TestCase;

class GuardianServiceTest extends TestCase
{
    private GuardianRepository&Mockery\MockInterface $guardians;
    private BookingRepository&Mockery\MockInterface $bookings;
    private EnrollmentRepository&Mockery\MockInterface $enrollments;
    private GuardianService $service;

    /** @var array<int, array<string, string>> */
    private array $meta = [];

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

        $this->guardians   = Mockery::mock(GuardianRepository::class);
        $this->bookings    = Mockery::mock(BookingRepository::class);
        $this->enrollments = Mockery::mock(EnrollmentRepository::class);

        $this->service = new GuardianService($this->guardians, $this->bookings, $this->enrollments);

        $meta = &$this->meta;
        Functions\when('update_user_meta')->alias(
            static function (int $userId, string $key, $value) use (&$meta): bool {
                $meta[$userId][$key] = (string) $value;
                return true;
            }
        );
        // A regular closure, not an arrow fn: arrow functions capture by value,
        // so the stub would read a snapshot of the meta taken at setUp.
        Functions\when('get_user_meta')->alias(
            static function (int $userId, string $key, bool $single = false) use (&$meta): string {
                return $meta[$userId][$key] ?? '';
            }
        );
        Functions\when('delete_user_meta')->alias(
            static function (int $userId, string $key) use (&$meta): bool {
                unset($meta[$userId][$key]);
                return true;
            }
        );
        // The birth-year range is validated against "this year", so pin it.
        Functions\when('current_time')->justReturn('2026');
        Functions\when('wp_generate_password')->justReturn('abc123def456');
        Functions\when('email_exists')->justReturn(false);
        Functions\when('is_wp_error')->alias(static fn ($thing): bool => $thing instanceof \WP_Error);
    }

    private function user(int $id, string $first = '', string $last = '', string $nickname = '', string $email = ''): \WP_User
    {
        $user             = Mockery::mock(\WP_User::class);
        $user->ID         = $id;
        $user->first_name = $first;
        $user->last_name  = $last;
        $user->nickname   = $nickname;
        $user->user_email = $email;

        return $user;
    }

    public function testCreateChildInsertsALoginLessUserAndLinksIt(): void
    {
        $captured = [];
        Functions\when('wp_insert_user')->alias(
            static function (array $args) use (&$captured): int {
                $captured = $args;
                return 42;
            }
        );

        $this->guardians->shouldReceive('insert')
            ->once()
            ->with(Mockery::on(static fn (GuardianLink $l): bool => $l->guardianId === 5 && $l->studentId === 42 && $l->relationship === 'Parent'))
            ->andReturn(7);

        $result = $this->service->createChild(5, ' Ada ', '2015', 'Parent');

        self::assertSame(42, $result);
        self::assertSame('Ada', $captured['display_name']);
        // The address is on the reserved .invalid TLD, so it can never receive mail.
        self::assertStringEndsWith('@child.invalid', $captured['user_email']);
        self::assertSame('1', $this->meta[42][GuardianService::META_CHILD]);
        self::assertSame('2015', $this->meta[42][GuardianService::META_BIRTH_YEAR]);
    }

    public function testCreateChildRejectsABlankName(): void
    {
        Functions\expect('wp_insert_user')->never();

        $result = $this->service->createChild(5, '   ');

        self::assertInstanceOf(\WP_Error::class, $result);
    }

    /**
     * A child whose link could not be written would be an unreachable orphan
     * account, so the user is removed again rather than left behind.
     */
    public function testCreateChildDeletesTheUserWhenTheLinkFails(): void
    {
        Functions\when('wp_insert_user')->justReturn(42);
        $this->guardians->shouldReceive('insert')->once()->andReturn(0);

        Functions\expect('wp_delete_user')->once()->with(42);

        self::assertInstanceOf(\WP_Error::class, $this->service->createChild(5, 'Ada'));
    }

    /**
     * @dataProvider unusableBirthYears
     */
    public function testCreateChildClearsAnUnusableBirthYear(string $submitted): void
    {
        Functions\when('wp_insert_user')->justReturn(42);
        $this->guardians->shouldReceive('insert')->once()->andReturn(7);

        $this->service->createChild(5, 'Ada', $submitted);

        self::assertArrayNotHasKey(GuardianService::META_BIRTH_YEAR, $this->meta[42] ?? []);
    }

    /** @return array<string, array{string}> */
    public static function unusableBirthYears(): array
    {
        return [
            'not a number'      => ['not-a-year'],
            'a full date'       => ['2015-04-02'],
            'too few digits'    => ['15'],
            'too many digits'   => ['20155'],
            'before 1900'       => ['1899'],
            'later than today'  => ['2027'],
        ];
    }

    public function testCanActForSelfAndOwnChildOnly(): void
    {
        $this->guardians->shouldReceive('isGuardianOf')->with(5, 42)->andReturn(true);
        $this->guardians->shouldReceive('isGuardianOf')->with(5, 99)->andReturn(false);

        self::assertTrue($this->service->canActFor(5, 5));
        self::assertTrue($this->service->canActFor(5, 42));
        self::assertFalse($this->service->canActFor(5, 99));
    }

    public function testCanActForRejectsNonPositiveIds(): void
    {
        self::assertFalse($this->service->canActFor(0, 42));
        self::assertFalse($this->service->canActFor(5, 0));
    }

    public function testPayerForResolvesTheGuardianAndFallsBackToTheStudent(): void
    {
        $this->guardians->shouldReceive('findByStudent')->with(42)->andReturn(new GuardianLink(5, 42));
        $this->guardians->shouldReceive('findByStudent')->with(9)->andReturn(null);

        self::assertSame(5, $this->service->payerFor(42));
        self::assertSame(9, $this->service->payerFor(9));
    }

    public function testHouseholdIdsCoverTheUserAndEveryChild(): void
    {
        $this->guardians->shouldReceive('findByGuardian')->with(5)->andReturn([
            new GuardianLink(5, 42),
            new GuardianLink(5, 43),
        ]);

        self::assertSame([5, 42, 43], $this->service->householdIds(5));
    }

    /**
     * The order is the feature: a guardian's default selection must be a child,
     * never themselves, so a lesson meant for a kid is not booked in the
     * parent's name by simply not touching the picker.
     */
    public function testBookableStudentsListsChildrenBeforeTheAccountHolder(): void
    {
        $this->guardians->shouldReceive('findByGuardian')->with(5)->andReturn([
            new GuardianLink(5, 42),
            new GuardianLink(5, 43),
        ]);

        Functions\when('get_userdata')->alias(fn (int $id): \WP_User => match ($id) {
            5       => $this->user(5, 'Grace', 'Hopper'),
            42      => $this->user(42, 'Ada', 'Lovelace'),
            default => $this->user(43, 'Alan', 'Turing'),
        });

        $students = $this->service->bookableStudents(5);

        self::assertSame(['Ada Lovelace', 'Alan Turing', 'Grace Hopper'], array_column($students, 'name'));
        self::assertSame([42, 43, 5], array_column($students, 'id'));
        self::assertSame([false, false, true], array_column($students, 'is_self'));
    }

    public function testChildrenReportsTheStoredBirthYear(): void
    {
        $this->meta[42][GuardianService::META_BIRTH_YEAR] = '2015';

        $this->guardians->shouldReceive('findByGuardian')->with(5)->andReturn([new GuardianLink(5, 42)]);
        Functions\when('get_userdata')->justReturn($this->user(42, 'Ada', 'Lovelace'));

        self::assertSame('2015', $this->service->children(5)[0]['birth_year']);
    }

    /**
     * A child added before this feature switched to a year has only the old full
     * date on record, and must still show a birth year.
     */
    public function testChildrenDerivesABirthYearFromALegacyDateOfBirth(): void
    {
        $this->meta[42][GuardianService::META_DOB] = '2015-04-02';

        $this->guardians->shouldReceive('findByGuardian')->with(5)->andReturn([new GuardianLink(5, 42)]);
        Functions\when('get_userdata')->justReturn($this->user(42, 'Ada', 'Lovelace'));

        self::assertSame('2015', $this->service->children(5)[0]['birth_year']);
    }

    /**
     * Saving a child drops the legacy full date. Without that, clearing the birth
     * year on a child who predates the change would leave the old date behind for
     * the fallback above to resurrect on the next read.
     */
    public function testSavingAChildClearsTheLegacyDateOfBirth(): void
    {
        $this->meta[42][GuardianService::META_DOB] = '2015-04-02';

        $this->guardians->shouldReceive('isGuardianOf')->with(5, 42)->andReturn(true);
        Functions\when('wp_update_user')->justReturn(42);

        self::assertNull($this->service->updateChild(5, 42, 'Ada L', ''));

        self::assertArrayNotHasKey(GuardianService::META_DOB, $this->meta[42] ?? []);
        self::assertArrayNotHasKey(GuardianService::META_BIRTH_YEAR, $this->meta[42] ?? []);

        $this->guardians->shouldReceive('findByGuardian')->with(5)->andReturn([new GuardianLink(5, 42)]);
        Functions\when('get_userdata')->justReturn($this->user(42, 'Ada', 'Lovelace'));

        self::assertSame('', $this->service->children(5)[0]['birth_year']);
    }

    public function testBookableStudentsIsJustTheUserWithoutChildren(): void
    {
        $this->guardians->shouldReceive('findByGuardian')->with(9)->andReturn([]);
        Functions\when('get_userdata')->justReturn($this->user(9, 'Ada', 'Lovelace'));

        $students = $this->service->bookableStudents(9);

        self::assertCount(1, $students);
        self::assertTrue($students[0]['is_self']);
    }

    public function testContactForPrefersTheGuardian(): void
    {
        $this->guardians->shouldReceive('findByStudent')->with(42)->andReturn(new GuardianLink(5, 42));
        Functions\when('get_userdata')->justReturn($this->user(5, 'Grace', 'Hopper', email: 'grace@example.test'));

        self::assertSame(
            ['id' => 5, 'name' => 'Grace Hopper', 'email' => 'grace@example.test'],
            $this->service->contactFor(42)
        );
    }

    public function testContactForFallsBackToTheStudentThemselves(): void
    {
        $this->guardians->shouldReceive('findByStudent')->with(9)->andReturn(null);
        Functions\when('get_userdata')->justReturn($this->user(9, 'Ada', 'Lovelace', email: 'ada@example.test'));

        self::assertSame(
            ['id' => 9, 'name' => 'Ada Lovelace', 'email' => 'ada@example.test'],
            $this->service->contactFor(9)
        );
    }

    public function testUpdateChildRefusesAStudentTheCallerDoesNotGuard(): void
    {
        $this->guardians->shouldReceive('isGuardianOf')->with(5, 99)->andReturn(false);
        Functions\expect('wp_update_user')->never();

        self::assertInstanceOf(\WP_Error::class, $this->service->updateChild(5, 99, 'Mallory'));
    }

    public function testUpdateChildRenamesAndStoresTheBirthYear(): void
    {
        $this->guardians->shouldReceive('isGuardianOf')->with(5, 42)->andReturn(true);
        Functions\expect('wp_update_user')
            ->once()
            ->with(['ID' => 42, 'display_name' => 'Ada L', 'nickname' => 'Ada L'])
            ->andReturn(42);

        self::assertNull($this->service->updateChild(5, 42, 'Ada L', '2015'));
        self::assertSame('2015', $this->meta[42][GuardianService::META_BIRTH_YEAR]);
    }

    public function testRemoveChildUnlinksAndDeletesAChildWithNoHistory(): void
    {
        $this->guardians->shouldReceive('isGuardianOf')->with(5, 42)->andReturn(true);
        $this->bookings->shouldReceive('findByStudent')->with(42)->andReturn([]);
        $this->enrollments->shouldReceive('findByStudent')->with(42)->andReturn([]);
        $this->guardians->shouldReceive('delete')->once()->with(5, 42)->andReturn(true);

        Functions\expect('wp_delete_user')->once()->with(42);

        self::assertNull($this->service->removeChild(5, 42));
    }

    /**
     * A child's id is referenced by lessons, payments and credits, so deleting
     * one with history would orphan all of it.
     */
    public function testRemoveChildRefusesOnceTheyHaveLessons(): void
    {
        $this->guardians->shouldReceive('isGuardianOf')->with(5, 42)->andReturn(true);
        $this->bookings->shouldReceive('findByStudent')->with(42)->andReturn([Mockery::mock(\stdClass::class)]);
        $this->guardians->shouldNotReceive('delete');

        $result = $this->service->removeChild(5, 42);

        self::assertInstanceOf(\WP_Error::class, $result);
        self::assertSame('has_history', $result->get_error_code());
    }

    public function testRemoveChildRefusesOnceTheyHaveEnrolments(): void
    {
        $this->guardians->shouldReceive('isGuardianOf')->with(5, 42)->andReturn(true);
        $this->bookings->shouldReceive('findByStudent')->with(42)->andReturn([]);
        $this->enrollments->shouldReceive('findByStudent')->with(42)->andReturn([Mockery::mock(\stdClass::class)]);
        $this->guardians->shouldNotReceive('delete');

        self::assertInstanceOf(\WP_Error::class, $this->service->removeChild(5, 42));
    }

    public function testRemoveChildRefusesAStudentTheCallerDoesNotGuard(): void
    {
        $this->guardians->shouldReceive('isGuardianOf')->with(5, 99)->andReturn(false);
        $this->guardians->shouldNotReceive('delete');

        self::assertInstanceOf(\WP_Error::class, $this->service->removeChild(5, 99));
    }

    public function testIsChildReadsTheMetaFlag(): void
    {
        $this->meta[42][GuardianService::META_CHILD] = '1';

        self::assertTrue(GuardianService::isChild(42));
        self::assertFalse(GuardianService::isChild(9));
    }
}