/*
 * Copyright (c) 2011, Vicent Marti
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#define RSTRING_NOT_MODIFIED

#include <stdio.h>
#include "ruby.h"

#ifdef HAVE_RUBY_ENCODING_H
#include <ruby/encoding.h>
#else
#define rb_enc_copy(dst, src)
#endif

#include "autolink.h"
#include "buffer.h"

static VALUE rb_cRinku;

extern void
upshtml_autolink(
	struct buf *ob,
	struct buf *text,
	unsigned int flags,
	const char *link_attr,
	void (*link_text_cb)(struct buf *ob, const struct buf *link, void *payload),
	void *payload);

static void
autolink_callback(struct buf *link_text, const struct buf *link, void *block)
{
	VALUE rb_link, rb_link_text;
	rb_link = rb_str_new(link->data, link->size);
	rb_link_text = rb_funcall((VALUE)block, rb_intern("call"), 1, rb_link);
	Check_Type(rb_link_text, T_STRING);
	bufput(link_text, RSTRING_PTR(rb_link_text), RSTRING_LEN(rb_link_text));
}

/*
 * Document-method: auto_link
 *
 * call-seq:
 *  auto_link(text, mode=:all, link_attr=nil)
 *  auto_link(text, mode=:all, link_attr=nil) { |link_text| ... }
 *
 * Parses a block of text looking for "safe" urls or email addresses,
 * and turns them into HTML links with the given attributes.
 *
 * NOTE: Currently the follow protocols are considered safe and are the
 * only ones that will be autolinked.
 *
 *		http:// https:// ftp:// mailto://
 *
 * Email addresses are also autolinked by default. URLs without a protocol
 * specifier but starting with 'www.' will also be autolinked, defaulting to
 * the 'http://' protocol.
 *
 * +text+ is a string in plain text or HTML markup. If the string is formatted in
 * HTML, Rinku is smart enough to skip the links that are already enclosed in <a>
 * tags.
 *
 * +mode+ is a symbol, either :all, :urls or :email_addresses, which specifies which
 * kind of links will be auto-linked.
 *
 * +link_attr+ is a string containing the link attributes for each link that
 * will be generated. These attributes are not sanitized and will be include as-is
 * in each generated link, e.g.
 *
 *	auto_link('http://www.pokemon.com', :all, 'target="_blank"')
 *	# => '<a href="http://www.pokemon.com" target="_blank">http://www.pokemon.com</a>'
 *
 * This string can be autogenerated from a hash using the Rails `tag_options` helper.
 *
 * +block+ The method takes an optional block argument. If a block is passed, it will
 * be yielded for each found link in the text, and its return value will be used instead
 * of the name of the link. E.g.
 *
 *	auto_link('Check it out at http://www.pokemon.com') do |url|
 *		"THE POKEMAN WEBSITEZ"
 *	end
 *	# => 'Check it out at <a href="http://www.pokemon.com">THE POKEMAN WEBSITEZ</a>'
 */
static VALUE
rb_rinku_autolink(int argc, VALUE *argv, VALUE self)
{
	VALUE result, rb_text, rb_mode, rb_html, rb_block;
	struct buf input_buf = {0, 0, 0, 0, 0}, *output_buf;
	int link_mode;
	const char *link_attr = NULL;
	ID mode_sym;

	rb_scan_args(argc, argv, "12&", &rb_text, &rb_mode, &rb_html, &rb_block);

	Check_Type(rb_text, T_STRING);

	if (!NIL_P(rb_mode)) {
		Check_Type(rb_mode, T_SYMBOL);
		mode_sym = SYM2ID(rb_mode);
	} else {
		mode_sym = rb_intern("all");
	}

	if (!NIL_P(rb_html)) {
		Check_Type(rb_html, T_STRING);
		link_attr = RSTRING_PTR(rb_html);
	}

	input_buf.data = RSTRING_PTR(rb_text);
	input_buf.size = RSTRING_LEN(rb_text);
	output_buf = bufnew(128);

	if (mode_sym == rb_intern("all"))
		link_mode = AUTOLINK_ALL;
	else if (mode_sym == rb_intern("email_addresses"))
		link_mode = AUTOLINK_EMAILS;
	else if (mode_sym == rb_intern("urls"))
		link_mode = AUTOLINK_URLS;
	else
		rb_raise(rb_eTypeError,
			"Invalid linking mode (possible values are :all, :urls, :email_addresses)");

	link_mode |= AUTOLINK_SANITIZE;

	if (RTEST(rb_block))
		upshtml_autolink(output_buf, &input_buf, link_mode, link_attr, &autolink_callback, (void*)rb_block);
	else
		upshtml_autolink(output_buf, &input_buf, link_mode, link_attr, NULL, NULL);

	result = rb_str_new(output_buf->data, output_buf->size);
	bufrelease(output_buf);

	/* force the input encoding */
	rb_enc_copy(result, rb_text);

	return result;
}

void Init_rinku()
{
	rb_cRinku = rb_define_class("Rinku", rb_cObject);
	rb_define_singleton_method(rb_cRinku, "auto_link", rb_rinku_autolink, -1);
}