/* markupwriter.vala
 *
 * Copyright (C) 2008-2009 Florian Brosch, Didier Villevalois
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
 *
 * Author:
 * 	Didier 'Ptitjes Villevalois <ptitjes@free.fr>
 */


/**
 * Writes markups and text to a file.
 */
public class Valadoc.MarkupWriter {
	protected WriteFunc write;
	protected int indent;

	protected long current_column = 0;
	protected bool last_was_tag;
	private bool wrap = true;

	public static string escape (string txt) {
		StringBuilder builder = new StringBuilder ();
		unowned string start = txt;
		unowned string pos;
		unichar c;

		for (pos = txt; (c = pos.get_char ()) != '\0'; pos = pos.next_char ()) {
			switch (c) {
			case '"':
				builder.append_len (start, (ssize_t) ((char*) pos - (char*) start));
				builder.append ("&quot;");
				start = pos.next_char ();
				break;

			case '<':
				builder.append_len (start, (ssize_t) ((char*) pos - (char*) start));
				builder.append ("&lt;");
				start = pos.next_char ();
				break;

			case '>':
				builder.append_len (start, (ssize_t) ((char*) pos - (char*) start));
				builder.append ("&gt;");
				start = pos.next_char ();
				break;

			case '&':
				builder.append_len (start, (ssize_t) ((char*) pos - (char*) start));
				builder.append ("&amp;");
				start = pos.next_char ();
				break;

			case '\'':
				builder.append_len (start, (ssize_t) ((char*) pos - (char*) start));
				builder.append ("&apos;");
				start = pos.next_char ();
				break;
			}
		}

		if (&txt == &start) {
			return txt;
		} else {
			builder.append_len (start, (ssize_t) ((char*) pos - (char*) start));
			return (owned) builder.str;
		}
	}

	/**
	 * Writes text to a destination like a {@link GLib.StringBuilder} or a {@link GLib.FileStream}
	 */
	public delegate void WriteFunc (string text);

	private const int MAX_COLUMN = 150;

	/**
	 * Initializes a new instance of the MarkupWriter
	 *
	 * @param write stream a WriteFunc
	 * @param xml_declaration specifies whether this file starts with an xml-declaration
	 */
	public MarkupWriter (owned WriteFunc write, bool xml_declaration = true) {
		this.write = (owned) write;
		if (xml_declaration) {
			do_write ("<?xml version=\"1.0\" encoding=\"utf-8\"?>");
		}
		indent = -1;
		last_was_tag = true;
	}

	/**
	 * Writes an start tag of a markup element to the file
	 *
	 * @param name the name of the markup
	 * @param attributes a list of name/value pairs
	 * @return this
	 */
	public unowned MarkupWriter start_tag (string name, string[]? attributes=null) {
		indent++;
		check_column (name);

		if (attributes.length % 2 != 0) {
			warning ("Given attributes array is not a list of pairs (name and value)");
			// This only effects array length of this in-parameter in this scope
			attributes.length -= 1;
		}

		var content = new StringBuilder ("<");
		content.append (name);
		for (int i = 0; i < attributes.length; i=i+2) {
			if (attributes[i+1] != null) {
				content.append_printf (" %s=\"%s\"", attributes[i], attributes[i+1]);
			}
		}
		content.append (">");

		do_write (content.str);
		last_was_tag = true;
		return this;
	}

	/**
	 * Writes a simple tag (<name />) to the file
	 *
	 * @param name the name of the markup
	 * @param attributes a list of name/value pairs
	 * @return this
	 */
	public unowned MarkupWriter simple_tag (string name, string[]? attributes=null) {
		indent++;
		check_column (name);

		if (attributes.length % 2 != 0) {
			warning ("Given attributes array is not a list of pairs (name and value)");
			// This only effects array length of this in-parameter in this scope
			attributes.length -= 1;
		}

		var content = new StringBuilder ("<");
		content.append (name);
		for (int i = 0; i < attributes.length; i=i+2) {
			if (attributes[i+1] != null) {
				content.append_printf (" %s=\"%s\"", attributes[i], attributes[i+1]);
			}
		}
		content.append ("/>");

		do_write (content.str);
		indent--;
		last_was_tag = true;
		return this;
	}

	/**
	 * Writes an end tag of a markup element to the file
	 *
	 * @param name the name of the markup
	 * @return this
	 */
	public unowned MarkupWriter end_tag (string name) {
		check_column (name, true);
		do_write ("</%s>".printf (name));
		indent--;
		last_was_tag = true;
		return this;
	}

	/**
	 * Writes the specified string to the output stream
	 *
	 * @see raw_text
	 * @return this
	 */
	public unowned MarkupWriter text (string text) {
		if (wrap && text.length + current_column > MAX_COLUMN) {
			long wrote = 0;
			while (wrote < text.length) {
				long space_pos = -1;
				for (long i = wrote + 1; i < text.length; i++) {
					if (text[i] == ' ') {
						if (i - wrote + current_column > MAX_COLUMN) {
							break;
						}
						space_pos = i;
					}
				}
				if (text.length - wrote + current_column <= MAX_COLUMN) {
					do_write (text.substring (wrote));
					wrote = text.length + 1;
				} else if (space_pos == -1) {
					// Force line break
				} else {
					do_write (text.substring (wrote, space_pos - wrote));
					wrote = space_pos + 1;
				}
				if (wrote < text.length) {
					break_line ();
					do_write ("  ");
				}
			}
		} else {
			do_write (text);
		}
		last_was_tag = false;
		return this;
	}

	/**
	 * Writes the specified string to the output stream
	 *
	 * @see text
	 * @return this
	 */
	public unowned MarkupWriter raw_text (string text) {
		do_write (text);
		last_was_tag = false;
		return this;
	}

	public void set_wrap (bool wrap) {
		this.wrap = wrap;
	}

	private void break_line () {
		write ("\n");
		write (string.nfill (indent * 2, ' '));
		current_column = indent * 2;
	}

	protected void do_write (string text) {
		if (wrap && current_column + text.length > MAX_COLUMN) {
			break_line ();
		}
		write (text);
		current_column += text.length;
	}

	private void check_column (string name, bool end_tag = false) {
		if (!wrap) {
			return;
		} else if (!end_tag && inline_element (name) /*&& !last_was_tag*/) {
			return;
		} else if (end_tag && content_inline_element (name)) {
			return;
		} else if (end_tag && !last_was_tag) {
			return;
		}
		break_line ();
	}

	protected virtual bool inline_element (string name) {
		return false;
	}

	protected virtual bool content_inline_element (string name) {
		return true;
	}
}