<?php
namespace Masterminds\HTML5\Parser;

/**
 * Standard events for HTML5.
 *
 * This is roughly analogous to a SAX2 or expat-style interface.
 * However, it is tuned specifically for HTML5, according to section 8
 * of the HTML5 specification.
 *
 * An event handler receives parser events. For a concrete
 * implementation, see DOMTreeBuilder.
 *
 * Quirks support in the parser is limited to close-in syntax (malformed
 * tags or attributes). Higher order syntax and semantic issues with a
 * document (e.g. mismatched tags, illegal nesting, etc.) are the
 * responsibility of the event handler implementation.
 *
 * See HTML5 spec section 8.2.4
 */
interface EventHandler
{

    const DOCTYPE_NONE = 0;

    const DOCTYPE_PUBLIC = 1;

    const DOCTYPE_SYSTEM = 2;

    /**
     * A doctype declaration.
     *
     * @param string $name
     *            The name of the root element.
     * @param int $idType
     *            One of DOCTYPE_NONE, DOCTYPE_PUBLIC, or DOCTYPE_SYSTEM.
     * @param string $id
     *            The identifier. For DOCTYPE_PUBLIC, this is the public ID. If DOCTYPE_SYSTEM,
     *            then this is a system ID.
     * @param boolean $quirks
     *            Indicates whether the builder should enter quirks mode.
     */
    public function doctype($name, $idType = 0, $id = null, $quirks = false);

    /**
     * A start tag.
     *
     * IMPORTANT: The parser watches the return value of this event. If this returns
     * an integer, the parser will switch TEXTMODE patters according to the int.
     *
     * This is how the Tree Builder can tell the Tokenizer when a certain tag should
     * cause the parser to go into RAW text mode.
     *
     * The HTML5 standard requires that the builder is the one that initiates this
     * step, and this is the only way short of a circular reference that we can
     * do that.
     *
     * Example: if a startTag even for a `script` name is fired, and the startTag()
     * implementation returns Tokenizer::TEXTMODE_RAW, then the tokenizer will
     * switch into RAW text mode and consume data until it reaches a closing
     * `script` tag.
     *
     * The textmode is automatically reset to Tokenizer::TEXTMODE_NORMAL when the
     * closing tag is encounter. **This behavior may change.**
     *
     * @param string $name
     *            The tag name.
     * @param array $attributes
     *            An array with all of the tag's attributes.
     * @param boolean $selfClosing
     *            An indicator of whether or not this tag is self-closing (<foo/>)
     * @return numeric One of the Tokenizer::TEXTMODE_* constants.
     */
    public function startTag($name, $attributes = array(), $selfClosing = false);

    /**
     * An end-tag.
     */
    public function endTag($name);

    /**
     * A comment section (unparsed character data).
     */
    public function comment($cdata);

    /**
     * A unit of parsed character data.
     *
     * Entities in this text are *already decoded*.
     */
    public function text($cdata);

    /**
     * Indicates that the document has been entirely processed.
     */
    public function eof();

    /**
     * Emitted when the parser encounters an error condition.
     */
    public function parseError($msg, $line, $col);

    /**
     * A CDATA section.
     *
     * @param string $data
     *            The unparsed character data.
     */
    public function cdata($data);

    /**
     * This is a holdover from the XML spec.
     *
     * While user agents don't get PIs, server-side does.
     *
     * @param string $name
     *            The name of the processor (e.g. 'php').
     * @param string $data
     *            The unparsed data.
     */
    public function processingInstruction($name, $data = null);
}
