<?php

namespace SilverStripe\Forms\Tests;

use SilverStripe\Dev\SapphireTest;
use SilverStripe\Forms\ConfirmedPasswordField;
use SilverStripe\Forms\FieldList;
use SilverStripe\Forms\FormField;
use SilverStripe\Forms\LiteralField;
use SilverStripe\Forms\Tab;
use SilverStripe\Forms\TextField;
use SilverStripe\Forms\EmailField;
use SilverStripe\Forms\FieldGroup;
use SilverStripe\Forms\TextareaField;
use SilverStripe\Forms\TabSet;
use SilverStripe\Forms\NumericField;
use SilverStripe\Forms\CompositeField;
use SilverStripe\Forms\FormAction;
use SilverStripe\Forms\HiddenField;

/**
 * Tests for FieldList
 *
 * @skipUpgrade
 * @todo        test for {@link FieldList->setValues()}. Need to check
 *  that the values that were set are the correct ones given back.
 * @todo        test for {@link FieldList->transform()} and {@link FieldList->makeReadonly()}.
 *  Need to ensure that it correctly transforms the FieldList object.
 * @todo        test for {@link FieldList->HiddenFields()}. Need to check
 *  the fields returned are the correct HiddenField objects for a
 *  given FieldList instance.
 * @todo        test for {@link FieldList->dataFields()}.
 * @todo        test for {@link FieldList->findOrMakeTab()}.
 * @todo        the same as above with insertBefore() and insertAfter()
 */
class FieldListTest extends SapphireTest
{
    public function testRecursiveWalk()
    {
        $fields = [
            new TextField('Name'),
            new EmailField('Email'),
            new HiddenField('Hidden'),
            new LiteralField('Literal', 'Literal content'),
            new CompositeField(
                new TextField('Day'),
                new TextField('Month'),
                new TextField('Year')
            ),
        ];
        $fieldList = new FieldList($fields);

        $count = 0;

        $fieldList->recursiveWalk(function (FormField $field) use (&$count) {
            ++$count;
        });

        $this->assertEquals(8, $count);
    }

    public function testFlattenFields()
    {
        $fields = [
            new TextField('Name'),
            new EmailField('Email'),
            new HiddenField('Hidden'),
            new LiteralField('Literal', 'Literal content'),
            $composite = new CompositeField(
                $day = new TextField('Day'),
                $month = new TextField('Month'),
                $year = new TextField('Year')
            ),
        ];
        $fieldList = new FieldList($fields);

        array_pop($fields);
        array_push($fields, $composite, $day, $month, $year);

        $this->assertEquals($fields, $fieldList->flattenFields()->toArray());
    }

    public function testSaveableFields()
    {
        $fields = [
            new TextField('Name'),
            new EmailField('Email'),
            new HiddenField('Hidden'),
            new LiteralField('Literal', 'Literal content'),
            new CompositeField(
                $day = new TextField('Day'),
                $month = new TextField('Month'),
                $year = new TextField('Year')
            ),
        ];
        $fieldList = new FieldList($fields);

        array_pop($fields);
        array_pop($fields);
        array_push($fields, $day, $month, $year);

        $this->assertEquals($fields, array_values($fieldList->saveableFields() ?? []));
    }

    public function testFieldNames()
    {
        $fields = [
            new TextField('Name'),
            new EmailField('Email'),
            new HiddenField('Hidden'),
            new LiteralField('Literal', 'Literal content'),
            new CompositeField(
                $day = new TextField('Day'),
                $month = new TextField('Month'),
                $year = new TextField('Year')
            ),
        ];
        $fieldList = new FieldList($fields);

        $this->assertEquals(['Name', 'Email', 'Hidden', 'Day', 'Month', 'Year'], $fieldList->dataFieldNames());
    }

    /**
     * Test adding a field to a tab in a set.
     */
    public function testAddFieldToTab()
    {
        $fields = new FieldList();
        $tab = new Tab('Root');
        $fields->push($tab);

        /* We add field objects to the FieldList, using two different methods */
        $fields->addFieldToTab('Root', new TextField('Country'));
        $fields->addFieldsToTab(
            'Root',
            [
            new EmailField('Email'),
            new TextField('Name'),
            ]
        );

        /* Check that the field objects were created */
        $this->assertNotNull($fields->dataFieldByName('Country'));
        $this->assertNotNull($fields->dataFieldByName('Email'));
        $this->assertNotNull($fields->dataFieldByName('Name'));

        /* The field objects in the set should be the same as the ones we created */
        $this->assertSame($fields->dataFieldByName('Country'), $tab->fieldByName('Country'));
        $this->assertSame($fields->dataFieldByName('Email'), $tab->fieldByName('Email'));
        $this->assertSame($fields->dataFieldByName('Name'), $tab->fieldByName('Name'));

        /* We'll have 3 fields inside the tab */
        $this->assertEquals(3, $tab->Fields()->count());
    }

    /**
     * Test that groups can be added to a fieldlist
     */
    public function testFieldgroup()
    {
        $fields = new FieldList();
        $tab = new Tab('Root');
        $fields->push($tab);

        $fields->addFieldsToTab(
            'Root',
            [
            $group1 = new FieldGroup(
                new TextField('Name'),
                new EmailField('Email')
            ),
            $group2 = new FieldGroup(
                new TextField('Company'),
                new TextareaField('Address')
            )
            ]
        );

        /* Check that the field objects were created */
        $this->assertNotNull($fields->dataFieldByName('Name'));
        $this->assertNotNull($fields->dataFieldByName('Email'));
        $this->assertNotNull($fields->dataFieldByName('Company'));
        $this->assertNotNull($fields->dataFieldByName('Address'));

        /* The field objects in the set should be the same as the ones we created */
        $this->assertSame($fields->dataFieldByName('Name'), $group1->fieldByName('Name'));
        $this->assertSame($fields->dataFieldByName('Email'), $group1->fieldByName('Email'));
        $this->assertSame($fields->dataFieldByName('Company'), $group2->fieldByName('Company'));
        $this->assertSame($fields->dataFieldByName('Address'), $group2->fieldByName('Address'));

        /* We'll have 2 fields directly inside the tab */
        $this->assertEquals(2, $tab->Fields()->count());
    }

    /**
     * Test removing a single field from a tab in a set.
     */
    public function testRemoveSingleFieldFromTab()
    {
        $fields = new FieldList();
        $tab = new Tab('Root');
        $fields->push($tab);

        /* We add a field to the "Root" tab */
        $fields->addFieldToTab('Root', new TextField('Country'));

        /* We have 1 field inside the tab, which is the field we just created */
        $this->assertEquals(1, $tab->Fields()->count());

        /* We remove the field from the tab */
        $fields->removeFieldFromTab('Root', 'Country');

        /* We'll have no fields in the tab now */
        $this->assertEquals(0, $tab->Fields()->count());
    }

    public function testRemoveTab()
    {
        $fields = new FieldList(
            new TabSet(
                'Root',
                $tab1 = new Tab('Tab1'),
                $tab2 = new Tab('Tab2'),
                $tab3 = new Tab('Tab3')
            )
        );

        $fields->removeByName('Tab2');
        $this->assertNull($fields->fieldByName('Root')->fieldByName('Tab2'));

        $this->assertEquals($tab1, $fields->fieldByName('Root')->fieldByName('Tab1'));
    }

    public function testHasTabSet()
    {
        $untabbedFields = new FieldList(
            new TextField('Field1')
        );
        $this->assertFalse($untabbedFields->hasTabSet());

        $tabbedFields = new FieldList(
            new TabSet(
                'Root',
                new Tab('Tab1')
            )
        );
        $this->assertTrue($tabbedFields->hasTabSet());
    }

    public function testFindTab()
    {
        $fields = new FieldList(
            $root = new TabSet(
                'Root',
                $tab1 = new Tab('Tab1'),
                $tab2 = new Tab('Tab2'),
                $tab3 = new Tab('Tab3'),
                $more = new TabSet(
                    'More',
                    $tab4 = new Tab('Tab4')
                )
            )
        );

        $this->assertEquals($fields->findTab('Root'), $root);
        $this->assertNull($fields->findTab('Tab5'));

        $this->assertNull($fields->findTab('Tab3'));
        $this->assertEquals($fields->findTab('Root.Tab3'), $tab3);

        $this->assertNull($fields->findTab('More'));
        $this->assertEquals($fields->findTab('Root.More'), $more);
        $this->assertEquals($fields->findTab('Root.More.Tab4'), $tab4);
    }

    /**
     * Test removing an array of fields from a tab in a set.
     */
    public function testRemoveMultipleFieldsFromTab()
    {
        $fields = new FieldList();
        $tab = new Tab('Root');
        $fields->push($tab);

        /* We add an array of fields, using addFieldsToTab() */
        $fields->addFieldsToTab(
            'Root',
            [
            new TextField('Name', 'Your name'),
            new EmailField('Email', 'Email address'),
            new NumericField('Number', 'Insert a number')
            ]
        );

        /* We have 3 fields inside the tab, which we just created */
        $this->assertEquals(3, $tab->Fields()->count());

        /* We remove the 3 fields from the tab */
        $fields->removeFieldsFromTab(
            'Root',
            [
            'Name',
            'Email',
            'Number'
            ]
        );

        /* We have no fields in the tab now */
        $this->assertEquals(0, $tab->Fields()->count());
    }

    public function testRemoveFieldByName()
    {
        $fields = new FieldList();
        $fields->push(new TextField('Name', 'Your name'));

        $this->assertEquals(1, $fields->count());
        $fields->removeByName('Name');
        $this->assertEquals(0, $fields->count());

        $fields->push(new TextField('Name[Field]', 'Your name'));
        $this->assertEquals(1, $fields->count());
        $fields->removeByName('Name[Field]');
        $this->assertEquals(0, $fields->count());
    }

    public function testDataFieldByName()
    {
        $fields = new FieldList();
        $fields->push($basic = new TextField('Name', 'Your name'));
        $fields->push($brack = new TextField('Name[Field]', 'Your name'));

        $this->assertEquals($basic, $fields->dataFieldByName('Name'));
        $this->assertEquals($brack, $fields->dataFieldByName('Name[Field]'));
    }

    /**
     * Test removing multiple fields from a set by their names in an array.
     */
    public function testRemoveFieldsByName()
    {
        $fields = new FieldList();

        /* First of all, we add some fields into our FieldList object */
        $fields->push(new TextField('Name', 'Your name'));
        $fields->push(new TextField('Email', 'Your email'));

        /* We have 2 fields in our set now */
        $this->assertEquals(2, $fields->count());

        /* Then, we call up removeByName() to take it out again */
        $fields->removeByName(['Name', 'Email']);

        /* We have 0 fields in our set now, as we've just removed the one we added */
        $this->assertEquals(0, $fields->count());
    }

    /**
     * Test replacing a field with another one.
     */
    public function testReplaceField()
    {
        $fields = new FieldList();
        $tab = new Tab('Root');
        $fields->push($tab);

        /* A field gets added to the set */
        $fields->addFieldToTab('Root', new TextField('Country'));

        $this->assertSame($fields->dataFieldByName('Country'), $tab->fieldByName('Country'));

        $fields->replaceField('Country', new EmailField('Email'));
        $this->assertEquals(1, $tab->Fields()->count());

        $fields = new FieldList();
        $fields->push(new TextField('Name', 'Your name'));
        $brack = new TextField('Name[Field]', 'Your name');

        $fields->replaceField('Name', $brack);
        $this->assertEquals(1, $fields->count());

        $this->assertEquals('Name[Field]', $fields->first()->getName());
    }

    public function testRenameField()
    {
        $fields = new FieldList();
        $nameField = new TextField('Name', 'Before title');
        $fields->push($nameField);

        /* The title of the field object is the same as what we put in */
        $this->assertSame('Before title', $nameField->Title());

        /* The field gets renamed to a different title */
        $fields->renameField('Name', 'After title');

        /* The title of the field object is the title we renamed to, this
        includes the original object we created ($nameField), and getting
        the field back out of the set */
        $this->assertSame('After title', $nameField->Title());
        $this->assertSame('After title', $fields->dataFieldByName('Name')->Title());
    }

    public function testReplaceAFieldInADifferentTab()
    {
        /* A FieldList gets created with a TabSet and some field objects */
        $FieldList = new FieldList(
            new TabSet(
                'Root',
                $main = new Tab(
                    'Main',
                    new TextField('A'),
                    new TextField('B')
                ),
                $other = new Tab(
                    'Other',
                    new TextField('C'),
                    new TextField('D')
                )
            )
        );

        /* The field "A" gets added to the FieldList we just created created */
        $FieldList->addFieldToTab('Root.Other', $newA = new TextField('A', 'New Title'));

        /* The field named "A" has been removed from the Main tab to make way for our new field named "A" in
        * Other tab. */
        $this->assertEquals(1, $main->Fields()->count());
        $this->assertEquals(3, $other->Fields()->count());
    }

    /**
     * Test finding a field that's inside a tabset, within another tab.
     */
    public function testNestedTabsFindingFieldByName()
    {
        $fields = new FieldList();

        /* 2 tabs get created within a TabSet inside our set */
        $tab = new TabSet(
            'Root',
            new TabSet(
                'MyContent',
                $mainTab = new Tab('Main'),
                $otherTab = new Tab('Others')
            )
        );
        $fields->push($tab);

        /* Some fields get added to the 2 tabs we just created */
        $fields->addFieldToTab('Root.MyContent.Main', new TextField('Country'));
        $fields->addFieldToTab('Root.MyContent.Others', new TextField('Email'));

        /* The fields we just added actually exists in the set */
        $this->assertNotNull($fields->dataFieldByName('Country'));
        $this->assertNotNull($fields->dataFieldByName('Email'));

        /* The fields we just added actually exist in the tabs */
        $this->assertNotNull($mainTab->fieldByName('Country'));
        $this->assertNotNull($otherTab->fieldByName('Email'));

        /* We have 1 field for each of the tabs */
        $this->assertEquals(1, $mainTab->Fields()->count());
        $this->assertEquals(1, $otherTab->Fields()->count());

        $this->assertNotNull($fields->fieldByName('Root.MyContent'));
        $this->assertNotNull($fields->fieldByName('Root.MyContent'));
    }

    public function testTabTitles()
    {
        $set = new FieldList(
            $rootTabSet = new TabSet(
                'Root',
                $tabSetWithoutTitle = new TabSet('TabSetWithoutTitle'),
                $tabSetWithTitle = new TabSet(
                    'TabSetWithTitle',
                    'My TabSet Title',
                    new Tab('ExistingChildTab')
                )
            )
        );

        $this->assertEquals(
            'My TabSet Title',
            $tabSetWithTitle->Title(),
            'Existing field title should be used'
        );

        $tabWithoutTitle = $set->findOrMakeTab('Root.TabWithoutTitle');
        $this->assertEquals(
            'Tab without title',
            $tabWithoutTitle->Title(),
            'Automatic conversion of tab identifiers through findOrMakeTab() with FormField::name_to_label()'
        );

        $tabWithTitle = $set->findOrMakeTab('Root.TabWithTitle', 'My Tab with Title');
        $this->assertEquals(
            'My Tab with Title',
            $tabWithTitle->Title(),
            'Setting of simple tab titles through findOrMakeTab()'
        );

        $childTabWithTitle = $set->findOrMakeTab('Root.TabSetWithoutTitle.NewChildTab', 'My Child Tab Title');
        $this->assertEquals(
            'My Child Tab Title',
            $childTabWithTitle->Title(),
            'Setting of nested tab titles through findOrMakeTab() works on last child tab'
        );
    }

    /**
     * Test pushing a field to a set.
     *
     * This tests {@link FieldList->push()}.
     */
    public function testPushFieldToSet()
    {
        $fields = new FieldList();

        /* A field named Country is added to the set */
        $fields->push(new TextField('Country'));

        /* We only have 1 field in the set */
        $this->assertEquals(1, $fields->count());

        /* Another field called Email is added to the set */
        $fields->push(new EmailField('Email'));

        /* There are now 2 fields in the set */
        $this->assertEquals(2, $fields->count());

        // Test that pushing a composite field without a name onto the set works
        // See ticket #2932
        $fields->push(
            new CompositeField(
                new TextField('Test1'),
                new TextField('Test2')
            )
        );
        $this->assertEquals(3, $fields->count());
    }

    /**
     * Test pushing a field to the beginning of a set.
     *
     * This tests {@link FieldList->unshift()}.
     */
    public function testPushFieldToBeginningOfSet()
    {
        $fields = new FieldList();

        /* A field named Country is added to the set */
        $fields->unshift(new TextField('Country'));

        /* We only have 1 field in the set */
        $this->assertEquals(1, $fields->count());

        /* Another field called Email is added to the set */
        $fields->unshift(new EmailField('Email'));

        /* There are now 2 fields in the set */
        $this->assertEquals(2, $fields->count());

        /* The most recently added field is at the beginning of the set */
        $this->assertEquals('Email', $fields->first()->getName());

        // Test that pushing a composite field without a name onto the set works
        $fields->unshift(
            new CompositeField(
                new TextField('Test1'),
                new TextField('Test2')
            )
        );
        $this->assertEquals(3, $fields->count());
    }

    /**
     * Test inserting a field before another in a set.
     *
     * This tests {@link FieldList->insertBefore()}.
     */
    public function testInsertBeforeFieldToSet()
    {
        $fields = new FieldList();

        /* 3 fields are added to the set */
        $fields->push(new TextField('Country'));
        $fields->push(new TextField('Email'));
        $fields->push(new TextField('FirstName'));

        /* We now have 3 fields in the set */
        $this->assertEquals(3, $fields->count());

        /* We insert another field called Title before the FirstName field */
        $fields->insertBefore('FirstName', new TextField('Title'));

        /* The field we just added actually exists in the set */
        $this->assertNotNull($fields->dataFieldByName('Title'));

        /* We now have 4 fields in the set */
        $this->assertEquals(4, $fields->count());

        /* The position of the Title field is at number 3 */
        $this->assertEquals('Title', $fields[2]->getName());

        /* Test arguments are accepted in either order */
        $fields->insertBefore('FirstName', new TextField('Surname'));

        /* The field we just added actually exists in the set */
        $this->assertNotNull($fields->dataFieldByName('Surname'));

        /* We now have 5 fields in the set */
        $this->assertEquals(5, $fields->count());

        /* The position of the Surname field is at number 4 */
        $this->assertEquals('Surname', $fields[3]->getName());

        /* Test that inserting before a field that doesn't exist simply appends
         * Confirm that a composite field doesn't break this */
        $fields->push(new CompositeField([ new TextField('Nested1'), new TextField('Nested2')]));
        $this->assertTrue((bool)$fields->insertBefore('DoesNotExist', new TextField('MyName')));
        $this->assertEquals('MyName', $fields->Last()->Name);
    }

    public function testInsertBeforeMultipleFields()
    {
        $fields = new FieldList(
            $root = new TabSet(
                "Root",
                $main = new Tab(
                    "Main",
                    $a = new TextField("A"),
                    $b = new TextField("B")
                )
            )
        );

        $fields->addFieldsToTab(
            'Root.Main',
            [
            new TextField('NewField1'),
            new TextField('NewField2')
            ],
            'B'
        );

        $this->assertEquals(
            array_keys($fields->dataFields() ?? []),
            [
            'A',
            'NewField1',
            'NewField2',
            'B'
            ]
        );
    }

    /**
     * Test inserting a field after another in a set.
     */
    public function testInsertAfterFieldToSet()
    {
        $fields = new FieldList();

        /* 3 fields are added to the set */
        $fields->push(new TextField('Country'));
        $fields->push(new TextField('Email'));
        $fields->push(new TextField('FirstName'));

        /* We now have 3 fields in the set */
        $this->assertEquals(3, $fields->count());

        /* A field called Title is inserted after the Country field */
        $fields->insertAfter('Country', new TextField('Title'));

        /* The field we just added actually exists in the set */
        $this->assertNotNull($fields->dataFieldByName('Title'));

        /* We now have 4 fields in the FieldList */
        $this->assertEquals(4, $fields->count());

        /* The position of the Title field should be at number 2 */
        $this->assertEquals('Title', $fields[1]->getName());

        /* Test arguments are accepted in either order */
        $fields->insertAfter('FirstName', new TextField('Surname'));

        /* The field we just added actually exists in the set */
        $this->assertNotNull($fields->dataFieldByName('Surname'));

        /* We now have 5 fields in the set */
        $this->assertEquals(5, $fields->count());

        /* The position of the Surname field is at number 5 */
        $this->assertEquals('Surname', $fields[4]->getName());

        /* Test that inserting before a field that doesn't exist simply appends
         * Confirm that a composite field doesn't break this */
        $fields->push(new CompositeField([ new TextField('Nested1'), new TextField('Nested2')]));
        $this->assertTrue((bool)$fields->insertAfter('DoesNotExist', new TextField('MyName')));
        $this->assertEquals('MyName', $fields->Last()->Name);
    }

    public function testrootFieldList()
    {
        /* Given a nested set of FormField, CompositeField, and FieldList objects */
        $FieldList = new FieldList(
            $root = new TabSet(
                "Root",
                $main = new Tab(
                    "Main",
                    $a = new TextField("A"),
                    $b = new TextField("B")
                )
            )
        );

        /* rootFieldList() should always evaluate to the same object: the topmost FieldList */
        $this->assertSame($FieldList, $FieldList->rootFieldList());
        $this->assertSame($FieldList, $root->rootFieldList());
        $this->assertSame($FieldList, $main->rootFieldList());
        $this->assertSame($FieldList, $a->rootFieldList());
        $this->assertSame($FieldList, $b->rootFieldList());

        /* If we push additional fields, they should also have the same rootFieldList() */
        $root->push($other = new Tab("Other"));
        $other->push($c = new TextField("C"));
        $root->push($third = new Tab("Third", $d = new TextField("D")));

        $this->assertSame($FieldList, $other->rootFieldList());
        $this->assertSame($FieldList, $third->rootFieldList());
        $this->assertSame($FieldList, $c->rootFieldList());
        $this->assertSame($FieldList, $d->rootFieldList());
    }

    public function testAddingDuplicateReplacesOldField()
    {
        /* Given a nested set of FormField, CompositeField, and FieldList objects */
        $FieldList = new FieldList(
            $root = new TabSet(
                "Root",
                $main = new Tab(
                    "Main",
                    $a = new TextField("A"),
                    $b = new TextField("B")
                )
            )
        );

        /* Adding new fields of the same names should replace the original fields */
        $newA = new TextField("A", "New A");
        $newB = new TextField("B", "New B");

        $FieldList->addFieldToTab("Root.Main", $newA);
        $FieldList->addFieldToTab("Root.Other", $newB);

        $this->assertSame($newA, $FieldList->dataFieldByName("A"));
        $this->assertSame($newB, $FieldList->dataFieldByName("B"));
        $this->assertEquals(1, $main->Fields()->count());

        /* Pushing fields on the end of the field set should remove them from the tab */
        $thirdA = new TextField("A", "Third A");
        $thirdB = new TextField("B", "Third B");
        $FieldList->push($thirdA);
        $FieldList->push($thirdB);

        $this->assertSame($thirdA, $FieldList->fieldByName("A"));
        $this->assertSame($thirdB, $FieldList->fieldByName("B"));

        $this->assertEquals(0, $main->Fields()->count());
    }

    public function testAddingFieldToNonExistentTabCreatesThatTab()
    {
        $FieldList = new FieldList(
            $root = new TabSet(
                "Root",
                $main = new Tab(
                    "Main",
                    $a = new TextField("A")
                )
            )
        );

        /* Add a field to a non-existent tab, and it will be created */
        $FieldList->addFieldToTab("Root.Other", $b = new TextField("B"));
        $this->assertNotNull($FieldList->fieldByName('Root')->fieldByName('Other'));
        $this->assertSame($b, $FieldList->fieldByName('Root')->fieldByName('Other')->Fields()->first());
    }

    public function testAddingFieldToATabWithTheSameNameAsTheField()
    {
        $FieldList = new FieldList(
            $root = new TabSet(
                "Root",
                $main = new Tab(
                    "Main",
                    $a = new TextField("A")
                )
            )
        );

        /* If you have a tab with the same name as the field, then technically it's a duplicate. However, it's
        * allowed because tab isn't a data field.  Only duplicate data fields are problematic */
        $FieldList->addFieldToTab("Root.MyName", $myName = new TextField("MyName"));
        $this->assertNotNull($FieldList->fieldByName('Root')->fieldByName('MyName'));
        $this->assertSame($myName, $FieldList->fieldByName('Root')->fieldByName('MyName')->Fields()->first());
    }

    public function testInsertBeforeWithNestedCompositeFields()
    {
        $FieldList = new FieldList(
            new TextField('A_pre'),
            new TextField('A'),
            new TextField('A_post'),
            $compositeA = new CompositeField(
                new TextField('B_pre'),
                new TextField('B'),
                new TextField('B_post'),
                $compositeB = new CompositeField(
                    new TextField('C_pre'),
                    new TextField('C'),
                    new TextField('C_post')
                )
            )
        );

        $FieldList->insertBefore(
            'A',
            $A_insertbefore = new TextField('A_insertbefore')
        );
        $this->assertSame(
            $A_insertbefore,
            $FieldList->dataFieldByName('A_insertbefore'),
            'Field on toplevel FieldList can be inserted'
        );

        $FieldList->insertBefore(
            'B',
            $B_insertbefore = new TextField('B_insertbefore')
        );
        $this->assertSame(
            $FieldList->dataFieldByName('B_insertbefore'),
            $B_insertbefore,
            'Field on one nesting level FieldList can be inserted'
        );

        $FieldList->insertBefore(
            'C',
            $C_insertbefore = new TextField('C_insertbefore')
        );
        $this->assertSame(
            $FieldList->dataFieldByName('C_insertbefore'),
            $C_insertbefore,
            'Field on two nesting levels FieldList can be inserted'
        );
    }

    /**
     * @todo check actual placement of fields
     */
    public function testInsertBeforeWithNestedTabsets()
    {
        $FieldListA = new FieldList(
            $tabSetA = new TabSet(
                'TabSet_A',
                $tabA1 = new Tab(
                    'Tab_A1',
                    new TextField('A_pre'),
                    new TextField('A'),
                    new TextField('A_post')
                ),
                $tabB1 = new Tab(
                    'Tab_B1',
                    new TextField('B')
                )
            )
        );
        $tabSetA->insertBefore(
            'A',
            $A_insertbefore = new TextField('A_insertbefore')
        );
        $this->assertEquals(
            $FieldListA->dataFieldByName('A_insertbefore'),
            $A_insertbefore,
            'Field on toplevel tab can be inserted'
        );

        $this->assertEquals(0, $tabA1->fieldPosition('A_pre'));
        $this->assertEquals(1, $tabA1->fieldPosition('A_insertbefore'));
        $this->assertEquals(2, $tabA1->fieldPosition('A'));
        $this->assertEquals(3, $tabA1->fieldPosition('A_post'));

        $FieldListB = new FieldList(
            new TabSet(
                'TabSet_A',
                $tabsetB = new TabSet(
                    'TabSet_B',
                    $tabB1 = new Tab(
                        'Tab_B1',
                        new TextField('C')
                    ),
                    $tabB2 = new Tab(
                        'Tab_B2',
                        new TextField('B_pre'),
                        new TextField('B'),
                        new TextField('B_post')
                    )
                )
            )
        );
        $FieldListB->insertBefore(
            'B',
            $B_insertbefore = new TextField('B_insertbefore')
        );
        $this->assertSame(
            $FieldListB->dataFieldByName('B_insertbefore'),
            $B_insertbefore,
            'Field on nested tab can be inserted'
        );
        $this->assertEquals(0, $tabB2->fieldPosition('B_pre'));
        $this->assertEquals(1, $tabB2->fieldPosition('B_insertbefore'));
        $this->assertEquals(2, $tabB2->fieldPosition('B'));
        $this->assertEquals(3, $tabB2->fieldPosition('B_post'));
    }

    public function testInsertAfterWithNestedCompositeFields()
    {
        $FieldList = new FieldList(
            new TextField('A_pre'),
            new TextField('A'),
            new TextField('A_post'),
            $compositeA = new CompositeField(
                new TextField('B_pre'),
                new TextField('B'),
                new TextField('B_post'),
                $compositeB = new CompositeField(
                    new TextField('C_pre'),
                    new TextField('C'),
                    new TextField('C_post')
                )
            )
        );

        $FieldList->insertAfter(
            'A',
            $A_insertafter = new TextField('A_insertafter')
        );
        $this->assertSame(
            $A_insertafter,
            $FieldList->dataFieldByName('A_insertafter'),
            'Field on toplevel FieldList can be inserted after'
        );

        $FieldList->insertAfter(
            'B',
            $B_insertafter = new TextField('B_insertafter')
        );
        $this->assertSame(
            $FieldList->dataFieldByName('B_insertafter'),
            $B_insertafter,
            'Field on one nesting level FieldList can be inserted after'
        );

        $FieldList->insertAfter(
            'C',
            $C_insertafter = new TextField('C_insertafter')
        );
        $this->assertSame(
            $FieldList->dataFieldByName('C_insertafter'),
            $C_insertafter,
            'Field on two nesting levels FieldList can be inserted after'
        );
    }

    /**
     * @todo check actual placement of fields
     */
    public function testInsertAfterWithNestedTabsets()
    {
        $FieldListA = new FieldList(
            $tabSetA = new TabSet(
                'TabSet_A',
                $tabA1 = new Tab(
                    'Tab_A1',
                    new TextField('A_pre'),
                    new TextField('A'),
                    new TextField('A_post')
                ),
                $tabB1 = new Tab(
                    'Tab_B1',
                    new TextField('B')
                )
            )
        );
        $tabSetA->insertAfter(
            'A',
            $A_insertafter = new TextField('A_insertafter')
        );
        $this->assertEquals(
            $FieldListA->dataFieldByName('A_insertafter'),
            $A_insertafter,
            'Field on toplevel tab can be inserted after'
        );
        $this->assertEquals(0, $tabA1->fieldPosition('A_pre'));
        $this->assertEquals(1, $tabA1->fieldPosition('A'));
        $this->assertEquals(2, $tabA1->fieldPosition('A_insertafter'));
        $this->assertEquals(3, $tabA1->fieldPosition('A_post'));

        $FieldListB = new FieldList(
            new TabSet(
                'TabSet_A',
                $tabsetB = new TabSet(
                    'TabSet_B',
                    $tabB1 = new Tab(
                        'Tab_B1',
                        new TextField('C')
                    ),
                    $tabB2 = new Tab(
                        'Tab_B2',
                        new TextField('B_pre'),
                        new TextField('B'),
                        new TextField('B_post')
                    )
                )
            )
        );
        $FieldListB->insertAfter(
            'B',
            $B_insertafter = new TextField('B_insertafter')
        );
        $this->assertSame(
            $FieldListB->dataFieldByName('B_insertafter'),
            $B_insertafter,
            'Field on nested tab can be inserted after'
        );
        $this->assertEquals(0, $tabB2->fieldPosition('B_pre'));
        $this->assertEquals(1, $tabB2->fieldPosition('B'));
        $this->assertEquals(2, $tabB2->fieldPosition('B_insertafter'));
        $this->assertEquals(3, $tabB2->fieldPosition('B_post'));
    }
    /**
     * FieldList::changeFieldOrder() should place specified fields in given
     * order then add any unspecified remainders at the end. Can be given an
     * array or list of arguments.
     */
    public function testChangeFieldOrder()
    {
        $fieldNames = ['A','B','C','D','E'];
        $setArray = new FieldList();
        $setArgs = new FieldList();
        foreach ($fieldNames as $fN) {
            $setArray->push(new TextField($fN));
            $setArgs->push(new TextField($fN));
        }

        $setArray->changeFieldOrder(['D','B','E']);
        $this->assertEquals(0, $setArray->fieldPosition('D'));
        $this->assertEquals(1, $setArray->fieldPosition('B'));
        $this->assertEquals(2, $setArray->fieldPosition('E'));
        $this->assertEquals(3, $setArray->fieldPosition('A'));
        $this->assertEquals(4, $setArray->fieldPosition('C'));

        $setArgs->changeFieldOrder('D', 'B', 'E');
        $this->assertEquals(0, $setArgs->fieldPosition('D'));
        $this->assertEquals(1, $setArgs->fieldPosition('B'));
        $this->assertEquals(2, $setArgs->fieldPosition('E'));
        $this->assertEquals(3, $setArgs->fieldPosition('A'));
        $this->assertEquals(4, $setArgs->fieldPosition('C'));

        unset($setArray, $setArgs);
    }

    public function testFieldPosition()
    {
        $set = new FieldList(
            new TextField('A'),
            new TextField('B'),
            new TextField('C')
        );

        $this->assertEquals(0, $set->fieldPosition('A'));
        $this->assertEquals(1, $set->fieldPosition('B'));
        $this->assertEquals(2, $set->fieldPosition('C'));

        $set->insertBefore('B', new TextField('AB'));
        $this->assertEquals(0, $set->fieldPosition('A'));
        $this->assertEquals(1, $set->fieldPosition('AB'));
        $this->assertEquals(2, $set->fieldPosition('B'));
        $this->assertEquals(3, $set->fieldPosition('C'));

        unset($set);
    }

    /**
     * FieldList::forTemplate() returns a concatenation of FieldHolder values.
     */
    public function testForTemplate()
    {
        $set = new FieldList(
            $a = new TextField('A'),
            $b = new TextField('B')
        );

        $this->assertEquals($a->FieldHolder() . $b->FieldHolder(), $set->forTemplate());
    }

    /**
     * FieldList::forTemplate() for an action list returns a concatenation of Field values.
     * Internally, this works by having FormAction::FieldHolder return just the field, but it's an important
     * use-case to test.
     */
    public function testForTemplateForActionList()
    {
        $set = new FieldList(
            $a = new FormAction('A'),
            $b = new FormAction('B')
        );

        $this->assertEquals($a->Field() . $b->Field(), $set->forTemplate());
    }

    public function testMakeFieldReadonly()
    {
        $FieldList = new FieldList(
            new TabSet(
                'Root',
                new Tab(
                    'Main',
                    new TextField('A'),
                    new TextField('B')
                )
            )
        );

        $FieldList->makeFieldReadonly('A');
        $this->assertTrue(
            $FieldList->dataFieldByName('A')->isReadonly(),
            'Field nested inside a TabSet and FieldList can be marked readonly by FieldList->makeFieldReadonly()'
        );
    }

    /**
     * Test VisibleFields and HiddenFields
     */
    public function testVisibleAndHiddenFields()
    {
        $fields = new FieldList(
            new TextField("A"),
            new TextField("B"),
            new HiddenField("C"),
            new Tabset(
                "Root",
                new Tab(
                    "D",
                    new TextField("D1"),
                    new HiddenField("D2")
                )
            )
        );

        $hidden = $fields->HiddenFields();
        // Inside hidden fields, all HiddenField objects are included, even nested ones
        $this->assertNotNull($hidden->dataFieldByName('C'));
        $this->assertNotNull($hidden->dataFieldByName('D2'));
        // Visible fields are not
        $this->assertNull($hidden->dataFieldByName('B'));
        $this->assertNull($hidden->dataFieldByName('D1'));

        $visible = $fields->VisibleFields();
        // Visible fields exclude top level HiddenField objects
        $this->assertNotNull($visible->dataFieldByName('A'));
        $this->assertNull($visible->dataFieldByName('C'));
        // But they don't exclude nested HiddenField objects.  This is a limitation; you should
        // put all your HiddenFields at the top level.
        $this->assertNotNull($visible->dataFieldByName('D2'));
    }

    public function testContainerField()
    {
        $fieldlist = new FieldList();
        $container = CompositeField::create();

        $this->assertNull($fieldlist->getContainerField());

        $fieldlist->setContainerField($container);
        $this->assertEquals($container, $fieldlist->getContainerField());

        $fieldlist->setContainerField(null);
        $this->assertNull($fieldlist->getContainerField());
    }
}