<?php

namespace Wikimedia\RemexHtml\TreeBuilder;

use Wikimedia\RemexHtml\HTMLData;
use Wikimedia\RemexHtml\Tokenizer\Attributes;
use Wikimedia\RemexHtml\Tokenizer\PlainAttributes;
use Wikimedia\RemexHtml\Tokenizer\Tokenizer;

/**
 * The "in body" insertion mode.
 */
class InBody extends InsertionMode {
	/**
	 * The tag names h1-h6, which are referred to at a couple of points.
	 * @var array<string,bool>
	 */
	private static $headingNames = [
		'h1' => true,
		'h2' => true,
		'h3' => true,
		'h4' => true,
		'h5' => true,
		'h6' => true
	];

	/**
	 * The tag names which can be closed by </body> or </html> without causing
	 * an error.
	 *
	 * @var array<string,bool>
	 */
	private static $implicitClose = [
		'dd' => true,
		'dt' => true,
		'li' => true,
		'optgroup' => true,
		'option' => true,
		'p' => true,
		'rb' => true,
		'rp' => true,
		'rt' => true,
		'rtc' => true,
		'tbody' => true,
		'td' => true,
		'tfoot' => true,
		'th' => true,
		'thead' => true,
		'tr' => true,
		'body' => true,
		'html' => true,
	];

	public function characters( $text, $start, $length, $sourceStart, $sourceLength ) {
		$handleNonNull = function ( $text, $start, $length, $sourceStart, $sourceLength ) {
			if ( strspn( $text, "\t\n\f\r ", $start, $length ) !== $length ) {
				$this->builder->framesetOK = false;
			}
			$this->builder->reconstructAFE( $sourceStart );
			$this->builder->insertCharacters( $text, $start, $length, $sourceStart, $sourceLength );
		};
		if ( !$this->builder->ignoreNulls ) {
			$this->stripNulls( $handleNonNull, $text, $start, $length, $sourceStart, $sourceLength );
		} else {
			$handleNonNull( $text, $start, $length, $sourceStart, $sourceLength );
		}
	}

	public function startTag( $name, Attributes $attrs, $selfClose, $sourceStart, $sourceLength ) {
		$mode = null;
		$textMode = null;
		$tokenizerState = null;
		$isNewAFE = false;
		$builder = $this->builder;
		$stack = $builder->stack;
		$dispatcher = $this->dispatcher;
		$void = false;

		switch ( $name ) {
			case 'html':
				$builder->error( 'merging unexpected html tag', $sourceStart );
				if ( $stack->hasTemplate() ) {
					return;
				}
				if ( $stack->length() < 1 ) {
					return;
				}
				$builder->mergeAttributes( $stack->item( 0 ), $attrs, $sourceStart, $sourceLength );
				return;

			case 'base':
			case 'basefont':
			case 'bgsound':
			case 'link':
			case 'meta':
			case 'noframes':
			case 'script':
			case 'style':
			case 'template':
			case 'title':
				$dispatcher->inHead->startTag(
					$name, $attrs, $selfClose, $sourceStart, $sourceLength );
				return;

			case 'body':
				if ( $stack->length() < 2 || $stack->hasTemplate() ) {
					$builder->error( 'ignored unexpected body tag', $sourceStart );
					return;
				}
				$body = $stack->item( 1 );
				if ( $body->htmlName !== 'body' ) {
					$builder->error( 'ignored unexpected body tag', $sourceStart );
					return;
				}
				$builder->error( 'merged unexpected body tag', $sourceStart );
				$this->builder->framesetOK = false;
				$this->builder->mergeAttributes( $body, $attrs, $sourceStart, $sourceLength );
				return;

			case 'frameset':
				if ( !$builder->framesetOK || $stack->length() < 2 || $stack->hasTemplate() ) {
					$builder->error( 'ignored unexpected frameset tag', $sourceStart );
					return;
				}
				$body = $stack->item( 1 );
				if ( $body->htmlName !== 'body' ) {
					$builder->error( 'ignored unexpected frameset tag', $sourceStart );
					return;
				}
				$builder->error( 'unexpected frameset tag erases body contents', $sourceStart );
				$builder->handler->removeNode( $body, $sourceStart );
				// Pop all the nodes from the bottom of the stack of open elements,
				// from the current node up to, but not including, the root html element.
				$n = $stack->length();
				for ( $i = 0; $i < $n - 1; $i++ ) {
					$stack->pop();
				}
				$mode = Dispatcher::IN_FRAMESET;
				// Insert as normal
				break;

			case 'address':
			case 'article':
			case 'aside':
			case 'blockquote':
			case 'center':
			case 'details':
			case 'dir':
			case 'div':
			case 'dl':
			case 'fieldset':
			case 'figcaption':
			case 'figure':
			case 'footer':
			case 'header':
			case 'main':
			case 'menu':
			case 'nav':
			case 'ol':
			case 'p':
			case 'section':
			case 'summary':
			case 'ul':
				$builder->closePInButtonScope( $sourceStart );
				break;

			case 'h1':
			case 'h2':
			case 'h3':
			case 'h4':
			case 'h5':
			case 'h6':
				$builder->closePInButtonScope( $sourceStart );
				if ( isset( self::$headingNames[$stack->current->htmlName] ) ) {
					$builder->error( 'invalid nested heading, closing previous', $sourceStart );
					$builder->pop( $sourceStart, 0 );
				}
				break;

			case 'pre':
			case 'listing':
				$builder->closePInButtonScope( $sourceStart );
				$builder->framesetOK = false;
				$textMode = Dispatcher::IN_PRE;
				break;

			case 'form':
				if ( $builder->formElement !== null && !$stack->hasTemplate() ) {
					$builder->error( 'ignoring nested form tag', $sourceStart );
					return;
				}
				$builder->closePInButtonScope( $sourceStart );
				$elt = $builder->insertElement( 'form', $attrs, false,
				$sourceStart, $sourceLength );
				if ( !$stack->hasTemplate() ) {
					$builder->formElement = $elt;
				}
				return;

			case 'li':
				$builder->framesetOK = false;
				for ( $idx = $stack->length() - 1; $idx >= 0; $idx-- ) {
					$node = $stack->item( $idx );
					$htmlName = $node->htmlName;
					if ( $htmlName === 'li' ) {
						$builder->generateImpliedEndTagsAndPop( 'li', $sourceStart, 0 );
						break;
					}
					if ( isset( HTMLData::$special[$node->namespace][$node->name] )
					&& $htmlName !== 'address' && $htmlName !== 'div' && $htmlName !== 'p'
					) {
						break;
					}
				}
				$builder->closePInButtonScope( $sourceStart );
				break;

			case 'dd':
			case 'dt':
				$builder->framesetOK = false;
				for ( $idx = $stack->length() - 1; $idx >= 0; $idx-- ) {
					$node = $stack->item( $idx );
					$htmlName = $node->htmlName;
					if ( $htmlName === 'dd' || $htmlName === 'dt' ) {
						$builder->generateImpliedEndTagsAndPop( $htmlName, $sourceStart, 0 );
						break;
					}
					if ( isset( HTMLData::$special[$node->namespace][$node->name] )
					&& $htmlName !== 'address' && $htmlName !== 'div' && $htmlName !== 'p'
					) {
						break;
					}
				}
				$builder->closePInButtonScope( $sourceStart );
				break;

			case 'plaintext':
				$builder->closePInButtonScope( $sourceStart );
				$tokenizerState = Tokenizer::STATE_PLAINTEXT;
				break;

			case 'button':
				if ( $stack->isInScope( 'button' ) ) {
					$builder->error( 'invalid nested button tag, closing previous', $sourceStart );
					$builder->generateImpliedEndTags( false, $sourceStart );
					$builder->popAllUpToName( 'button', $sourceStart, 0 );
				}
				$builder->reconstructAFE( $sourceStart );
				$builder->framesetOK = false;
				break;

			case 'a':
				$elt = $builder->afe->findElementByName( 'a' );
				if ( $elt !== null ) {
					$builder->error( 'invalid nested a tag, closing previous', $sourceStart );
					$builder->adoptionAgency( 'a', $sourceStart, 0 );
					if ( $builder->afe->isInList( $elt ) ) {
						$builder->afe->remove( $elt );
					}
					if ( $elt->stackIndex !== null ) {
						$stack->remove( $elt );
					}
				}
				$builder->reconstructAFE( $sourceStart );
				$isNewAFE = true;
				break;

			case 'b':
			case 'big':
			case 'code':
			case 'em':
			case 'font':
			case 'i':
			case 's':
			case 'small':
			case 'strike':
			case 'strong':
			case 'tt':
			case 'u':
				$builder->reconstructAFE( $sourceStart );
				$isNewAFE = true;
				break;

			case 'nobr':
				$builder->reconstructAFE( $sourceStart );
				if ( $stack->isInScope( 'nobr' ) ) {
					$builder->error( 'invalid nested nobr tag, closing previous', $sourceStart );
					$builder->adoptionAgency( 'nobr', $sourceStart, 0 );
					$builder->reconstructAFE( $sourceStart );
				}
				$isNewAFE = true;
				break;

			case 'applet':
			case 'marquee':
			case 'object':
				$builder->reconstructAFE( $sourceStart );
				$builder->afe->insertMarker();
				$builder->framesetOK = false;
				break;

			case 'table':
				if ( $builder->quirks !== TreeBuilder::QUIRKS ) {
					$builder->closePInButtonScope( $sourceStart );
				}
				$builder->framesetOK = false;
				$mode = Dispatcher::IN_TABLE;
				break;

			case 'area':
			case 'br':
			case 'embed':
			case 'img':
			case 'keygen':
			case 'wbr':
				$builder->reconstructAFE( $sourceStart );
				$dispatcher->ack = true;
				$void = true;
				$builder->framesetOK = false;
				break;

			case 'input':
				$builder->reconstructAFE( $sourceStart );
				$dispatcher->ack = true;
				$void = true;
				if ( !isset( $attrs['type'] ) || strcasecmp( $attrs['type'], 'hidden' ) !== 0 ) {
					$builder->framesetOK = false;
				}
				break;

			case 'menuitem':
			case 'param':
			case 'source':
			case 'track':
				$dispatcher->ack = true;
				$void = true;
				break;

			case 'hr':
				$builder->closePInButtonScope( $sourceStart );
				$dispatcher->ack = true;
				$void = true;
				$builder->framesetOK = false;
				break;

			case 'image':
				$builder->error( 'invalid "image" tag, assuming "img"', $sourceStart );
				$this->startTag( 'img', $attrs, $selfClose, $sourceStart, $sourceLength );
				return;

			case 'textarea':
				$tokenizerState = Tokenizer::STATE_RCDATA;
				$textMode = Dispatcher::IN_TEXTAREA;
				$builder->framesetOK = false;
				break;

			case 'xmp':
				$builder->closePInButtonScope( $sourceStart );
				$builder->reconstructAFE( $sourceStart );
				$builder->framesetOK = false;
				$tokenizerState = Tokenizer::STATE_RAWTEXT;
				$textMode = Dispatcher::TEXT;
				break;

			case 'iframe':
				$builder->framesetOK = false;
				$tokenizerState = Tokenizer::STATE_RAWTEXT;
				$textMode = Dispatcher::TEXT;
				break;

			case 'noscript':
				if ( !$builder->scriptingFlag ) {
					$builder->reconstructAFE( $sourceStart );
					break;
				}
				// fall through
			case 'noembed':
				$tokenizerState = Tokenizer::STATE_RAWTEXT;
				$textMode = Dispatcher::TEXT;
				break;

			case 'select':
				$builder->reconstructAFE( $sourceStart );
				$builder->framesetOK = false;
				if ( $dispatcher->isInTableMode() ) {
					$mode = Dispatcher::IN_SELECT_IN_TABLE;
				} else {
					$mode = Dispatcher::IN_SELECT;
				}
				break;

			case 'optgroup':
			case 'option':
				if ( $stack->current->htmlName === 'option' ) {
					$builder->pop( $sourceStart, 0 );
				}
				$builder->reconstructAFE( $sourceStart );
				break;

			case 'rb':
			case 'rtc':
				if ( $stack->isInScope( 'ruby' ) ) {
					$builder->generateImpliedEndTags( false, $sourceStart );
					if ( $stack->current->htmlName !== 'ruby'
					) {
						$builder->error( "<$name> is not a child of <ruby>", $sourceStart );
					}
				}
				break;

			case 'rp':
			case 'rt':
				if ( $stack->isInScope( 'ruby' ) ) {
					$builder->generateImpliedEndTags( 'rtc', $sourceStart );
					if ( !in_array( $stack->current->htmlName, [ 'ruby', 'rtc' ] ) ) {
						$builder->error( "<$name> is not a child of <ruby> or <rtc>", $sourceStart );
					}
				}
				break;

			case 'math':
				$builder->reconstructAFE( $sourceStart );
				$attrs = new ForeignAttributes( $attrs, 'math' );
				$dispatcher->ack = true;
				$builder->insertForeign( HTMLData::NS_MATHML, 'math', $attrs, $selfClose,
					$sourceStart, $sourceLength );
				return;

			case 'svg':
				$builder->reconstructAFE( $sourceStart );
				$attrs = new ForeignAttributes( $attrs, 'svg' );
				$dispatcher->ack = true;
				$builder->insertForeign( HTMLData::NS_SVG, 'svg', $attrs, $selfClose,
					$sourceStart, $sourceLength );
				return;

			case 'caption':
			case 'col':
			case 'colgroup':
			case 'frame':
			case 'head':
			case 'tbody':
			case 'td':
			case 'tfoot':
			case 'th':
			case 'thead':
			case 'tr':
				$builder->error( "$name is invalid in body mode", $sourceStart );
				return;

			default:
				$builder->reconstructAFE( $sourceStart );
		}

		// Generic element insertion, for all cases that didn't return above
		$element = $builder->insertElement( $name, $attrs, $void,
			$sourceStart, $sourceLength );
		if ( $isNewAFE ) {
			$builder->afe->push( $element );
		}

		if ( $tokenizerState !== null ) {
			$builder->tokenizer->switchState( $tokenizerState, $name );
		}
		if ( $mode !== null ) {
			$dispatcher->switchMode( $mode );
		} elseif ( $textMode !== null ) {
			$dispatcher->switchAndSave( $textMode );
		}
	}

	public function endTag( $name, $sourceStart, $sourceLength ) {
		$builder = $this->builder;
		$stack = $builder->stack;
		$dispatcher = $this->dispatcher;

		switch ( $name ) {
			case 'template':
				$dispatcher->inHead->endTag( $name, $sourceStart, $sourceLength );
				break;

			case 'body':
				if ( !$stack->isInScope( 'body' ) ) {
					$builder->error( '</body> has no matching start tag in scope', $sourceStart );
					break;
				}
				$builder->checkUnclosed( self::$implicitClose, $sourceStart );
				$dispatcher->switchMode( Dispatcher::AFTER_BODY );
				break;

			case 'html':
				if ( !$stack->isInScope( 'body' ) ) {
					$builder->error( '</html> found in body mode but the body is not in scope',
						$sourceStart );
					break;
				}
				$builder->checkUnclosed( self::$implicitClose, $sourceStart );
				$dispatcher->switchMode( Dispatcher::AFTER_BODY )
					->endTag( $name, $sourceStart, $sourceLength );
				break;

			case 'address':
			case 'article':
			case 'aside':
			case 'blockquote':
			case 'button':
			case 'center':
			case 'details':
			case 'dir':
			case 'div':
			case 'dl':
			case 'fieldset':
			case 'figcaption':
			case 'figure':
			case 'footer':
			case 'header':
			case 'listing':
			case 'main':
			case 'menu':
			case 'nav':
			case 'ol':
			case 'pre':
			case 'section':
			case 'summary':
			case 'ul':
				if ( !$stack->isInScope( $name ) ) {
					$builder->error( "unmatched </$name>, ignoring", $sourceStart );
					break;
				}
				$builder->generateImpliedEndTagsAndPop( $name, $sourceStart, $sourceLength );
				break;

			case 'form':
				if ( !$stack->hasTemplate() ) {
					$node = $builder->formElement;
					$builder->formElement = null;
					if ( $node === null ) {
						$builder->error( "found </form> when there is no open form element",
							$sourceStart );
						break;
					}
					if ( !$stack->isElementInScope( $node ) ) {
						$builder->error( "found </form> when there is no form in scope",
						$sourceStart );
						break;
					}
					$builder->generateImpliedEndTags( false, $sourceStart );
					if ( $stack->current === $node ) {
						$builder->pop( $sourceStart, $sourceLength );
					} else {
						$builder->error( "found </form> when there are tags open " .
							"which cannot be closed automatically", $sourceStart );
						$stack->remove( $node );
						// FIXME cannot garbage collect in Serializer since children
						// of the form are still in the stack
						// $builder->handler->endTag( $node, $sourceStart, $sourceLength );
					}
				} else {
					if ( !$stack->isInScope( 'form' ) ) {
						$builder->error( "found </form> when there is no form in scope",
							$sourceStart );
						break;
					}
					$builder->generateImpliedEndTagsAndPop( 'form', $sourceStart, $sourceLength );
				}
				break;

			case 'p':
				if ( !$stack->isInButtonScope( 'p' ) ) {
					$builder->error( "found </p> when there is no p in scope",
						$sourceStart );
					$builder->insertElement( 'p', new PlainAttributes, false, $sourceStart, 0 );
					$builder->pop( $sourceStart, $sourceLength );
					break;
				}
				$builder->generateImpliedEndTagsAndPop( 'p', $sourceStart, $sourceLength );
				break;

			case 'li':
				if ( !$stack->isInListScope( 'li' ) ) {
					$builder->error( "found </li> when there is no li in scope, ignoring",
						$sourceStart );
					break;
				}
				$builder->generateImpliedEndTagsAndPop( 'li', $sourceStart, $sourceLength );
				break;

			case 'dd':
			case 'dt':
				if ( !$stack->isInScope( $name ) ) {
					$builder->error( "found </$name> when there is no $name in scope, ignoring",
						$sourceStart );
					break;
				}
				$builder->generateImpliedEndTagsAndPop( $name, $sourceStart, $sourceLength );
				break;

			case 'h1':
			case 'h2':
			case 'h3':
			case 'h4':
			case 'h5':
			case 'h6':
				if ( !$stack->isOneOfSetInScope( self::$headingNames ) ) {
					$builder->error( "found </$name> when there is no heading tag in scope, ignoring",
						$sourceStart );
					break;
				}
				$builder->generateImpliedEndTags( false, $sourceStart );
				if ( $stack->current->htmlName !== $name ) {
					$builder->error( "end tag </$name> assumed to close non-matching heading tag",
						$sourceStart );
				}
				$builder->popAllUpToNames( self::$headingNames, $sourceStart, $sourceLength );
				break;

			case 'a':
			case 'b':
			case 'big':
			case 'code':
			case 'em':
			case 'font':
			case 'i':
			case 'nobr':
			case 's':
			case 'small':
			case 'strike':
			case 'strong':
			case 'tt':
			case 'u':
				$builder->adoptionAgency( $name, $sourceStart, $sourceLength );
				break;

			case 'applet':
			case 'marquee':
			case 'object':
				if ( !$stack->isInScope( $name ) ) {
					$builder->error( "found </$name> when there is no $name in scope",
						$sourceStart );
					break;
				}
				$builder->generateImpliedEndTags( false, $sourceStart );
				if ( $stack->current->htmlName !== $name ) {
					$builder->error( "found </$name> when there are tags open which " .
						"cannot be implicitly closed, closing them anyway", $sourceStart );
				}
				$builder->popAllUpToName( $name, $sourceStart, $sourceLength );
				$builder->afe->clearToMarker();
				break;

			case 'br':
				$builder->error( 'end tag </br> is invalid, assuming start tag', $sourceStart );
				$this->startTag( $name, new PlainAttributes, false, $sourceStart, $sourceLength );
				break;

			default:
				$builder->anyOtherEndTag( $name, $sourceStart, $sourceLength );
				break;
		}
	}

	public function endDocument( $pos ) {
		$allowed = [
			'dd' => true,
			'dt' => true,
			'li' => true,
			'p' => true,
			'tbody' => true,
			'td' => true,
			'tfoot' => true,
			'th' => true,
			'thead' => true,
			'tr' => true,
			'body' => true,
			'html' => true,
		];

		$this->builder->checkUnclosed( $allowed, $pos );
		if ( !$this->dispatcher->templateModeStack->isEmpty() ) {
			$this->dispatcher->inTemplate->endDocument( $pos );
		} else {
			$this->builder->stopParsing( $pos );
		}
	}
}