/* ui-diff.c: show diff between two blobs
 *
 * Copyright (C) 2006-2014 cgit Development Team <cgit@lists.zx2c4.com>
 *
 * Licensed under GNU General Public License v2
 *   (see COPYING for full license text)
 */

#include "cgit.h"
#include "ui-diff.h"
#include "html.h"
#include "ui-shared.h"
#include "ui-ssdiff.h"

struct object_id old_rev_oid[1];
struct object_id new_rev_oid[1];

static int files, slots;
static int total_adds, total_rems, max_changes;
static int lines_added, lines_removed;

static struct fileinfo {
	char status;
	struct object_id old_oid[1];
	struct object_id new_oid[1];
	unsigned short old_mode;
	unsigned short new_mode;
	char *old_path;
	char *new_path;
	unsigned int added;
	unsigned int removed;
	unsigned long old_size;
	unsigned long new_size;
	unsigned int binary:1;
} *items;

static int use_ssdiff = 0;
static struct diff_filepair *current_filepair;
static const char *current_prefix;

struct diff_filespec *cgit_get_current_old_file(void)
{
	return current_filepair->one;
}

struct diff_filespec *cgit_get_current_new_file(void)
{
	return current_filepair->two;
}

static void print_fileinfo(struct fileinfo *info)
{
	char *class;

	switch (info->status) {
	case DIFF_STATUS_ADDED:
		class = "add";
		break;
	case DIFF_STATUS_COPIED:
		class = "cpy";
		break;
	case DIFF_STATUS_DELETED:
		class = "del";
		break;
	case DIFF_STATUS_MODIFIED:
		class = "upd";
		break;
	case DIFF_STATUS_RENAMED:
		class = "mov";
		break;
	case DIFF_STATUS_TYPE_CHANGED:
		class = "typ";
		break;
	case DIFF_STATUS_UNKNOWN:
		class = "unk";
		break;
	case DIFF_STATUS_UNMERGED:
		class = "stg";
		break;
	default:
		die("bug: unhandled diff status %c", info->status);
	}

	html("<tr>");
	html("<td class='mode'>");
	if (is_null_oid(info->new_oid)) {
		cgit_print_filemode(info->old_mode);
	} else {
		cgit_print_filemode(info->new_mode);
	}

	if (info->old_mode != info->new_mode &&
	    !is_null_oid(info->old_oid) &&
	    !is_null_oid(info->new_oid)) {
		html("<span class='modechange'>[");
		cgit_print_filemode(info->old_mode);
		html("]</span>");
	}
	htmlf("</td><td class='%s'>", class);
	cgit_diff_link(info->new_path, NULL, NULL, ctx.qry.head, ctx.qry.oid,
		       ctx.qry.oid2, info->new_path);
	if (info->status == DIFF_STATUS_COPIED || info->status == DIFF_STATUS_RENAMED) {
		htmlf(" (%s from ",
		      info->status == DIFF_STATUS_COPIED ? "copied" : "renamed");
		html_txt(info->old_path);
		html(")");
	}
	html("</td><td class='right'>");
	if (info->binary) {
		htmlf("bin</td><td class='graph'>%ld -> %ld bytes",
		      info->old_size, info->new_size);
		return;
	}
	htmlf("%d", info->added + info->removed);
	html("</td><td class='graph'>");
	htmlf("<table summary='file diffstat' width='%d%%'><tr>", (max_changes > 100 ? 100 : max_changes));
	htmlf("<td class='add' style='width: %.1f%%;'/>",
	      info->added * 100.0 / max_changes);
	htmlf("<td class='rem' style='width: %.1f%%;'/>",
	      info->removed * 100.0 / max_changes);
	htmlf("<td class='none' style='width: %.1f%%;'/>",
	      (max_changes - info->removed - info->added) * 100.0 / max_changes);
	html("</tr></table></td></tr>\n");
}

static void count_diff_lines(char *line, int len)
{
	if (line && (len > 0)) {
		if (line[0] == '+')
			lines_added++;
		else if (line[0] == '-')
			lines_removed++;
	}
}

static int show_filepair(struct diff_filepair *pair)
{
	/* Always show if we have no limiting prefix. */
	if (!current_prefix)
		return 1;

	/* Show if either path in the pair begins with the prefix. */
	if (starts_with(pair->one->path, current_prefix) ||
	    starts_with(pair->two->path, current_prefix))
		return 1;

	/* Otherwise we don't want to show this filepair. */
	return 0;
}

static void inspect_filepair(struct diff_filepair *pair)
{
	int binary = 0;
	unsigned long old_size = 0;
	unsigned long new_size = 0;

	if (!show_filepair(pair))
		return;

	files++;
	lines_added = 0;
	lines_removed = 0;
	cgit_diff_files(&pair->one->oid, &pair->two->oid, &old_size, &new_size,
			&binary, 0, ctx.qry.ignorews, count_diff_lines);
	if (files >= slots) {
		if (slots == 0)
			slots = 4;
		else
			slots = slots * 2;
		items = xrealloc(items, slots * sizeof(struct fileinfo));
	}
	items[files-1].status = pair->status;
	oidcpy(items[files-1].old_oid, &pair->one->oid);
	oidcpy(items[files-1].new_oid, &pair->two->oid);
	items[files-1].old_mode = pair->one->mode;
	items[files-1].new_mode = pair->two->mode;
	items[files-1].old_path = xstrdup(pair->one->path);
	items[files-1].new_path = xstrdup(pair->two->path);
	items[files-1].added = lines_added;
	items[files-1].removed = lines_removed;
	items[files-1].old_size = old_size;
	items[files-1].new_size = new_size;
	items[files-1].binary = binary;
	if (lines_added + lines_removed > max_changes)
		max_changes = lines_added + lines_removed;
	total_adds += lines_added;
	total_rems += lines_removed;
}

static void cgit_print_diffstat(const struct object_id *old_oid,
				const struct object_id *new_oid,
				const char *prefix)
{
	int i;

	html("<div class='diffstat-header'>");
	cgit_diff_link("Diffstat", NULL, NULL, ctx.qry.head, ctx.qry.oid,
		       ctx.qry.oid2, NULL);
	if (prefix) {
		html(" (limited to '");
		html_txt(prefix);
		html("')");
	}
	html("</div>");
	html("<table summary='diffstat' class='diffstat'>");
	max_changes = 0;
	cgit_diff_tree(old_oid, new_oid, inspect_filepair, prefix,
		       ctx.qry.ignorews);
	for (i = 0; i<files; i++)
		print_fileinfo(&items[i]);
	html("</table>");
	html("<div class='diffstat-summary'>");
	htmlf("%d files changed, %d insertions, %d deletions",
	      files, total_adds, total_rems);
	html("</div>");
}


/*
 * print a single line returned from xdiff
 */
static void print_line(char *line, int len)
{
	char *class = "ctx";
	char c = line[len-1];

	if (line[0] == '+')
		class = "add";
	else if (line[0] == '-')
		class = "del";
	else if (line[0] == '@')
		class = "hunk";

	htmlf("<div class='%s'>", class);
	line[len-1] = '\0';
	html_txt(line);
	html("</div>");
	line[len-1] = c;
}

static void header(const struct object_id *oid1, char *path1, int mode1,
		   const struct object_id *oid2, char *path2, int mode2)
{
	char *abbrev1, *abbrev2;
	int subproject;

	subproject = (S_ISGITLINK(mode1) || S_ISGITLINK(mode2));
	html("<div class='head'>");
	html("diff --git a/");
	html_txt(path1);
	html(" b/");
	html_txt(path2);

	if (mode1 == 0)
		htmlf("<br/>new file mode %.6o", mode2);

	if (mode2 == 0)
		htmlf("<br/>deleted file mode %.6o", mode1);

	if (!subproject) {
		abbrev1 = xstrdup(find_unique_abbrev(oid1, DEFAULT_ABBREV));
		abbrev2 = xstrdup(find_unique_abbrev(oid2, DEFAULT_ABBREV));
		htmlf("<br/>index %s..%s", abbrev1, abbrev2);
		free(abbrev1);
		free(abbrev2);
		if (mode1 != 0 && mode2 != 0) {
			htmlf(" %.6o", mode1);
			if (mode2 != mode1)
				htmlf("..%.6o", mode2<style>pre { line-height: 125%; }
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.highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */</style><div class="highlight"><pre><span></span><span class="ch">#!/bin/sh</span>
<span class="c1"># This script can be used to implement syntax highlighting in the cgit</span>
<span class="c1"># tree-view by referring to this file with the source-filter or repo.source-</span>
<span class="c1"># filter options in cgitrc.</span>
<span class="c1">#</span>
<span class="c1"># This script requires a shell supporting the ${var##pattern} syntax.</span>
<span class="c1"># It is supported by at least dash and bash, however busybox environments</span>
<span class="c1"># might have to use an external call to sed instead.</span>
<span class="c1">#</span>
<span class="c1"># Note: the highlight command (http://www.andre-simon.de/) uses css for syntax</span>
<span class="c1"># highlighting, so you&#39;ll probably want something like the following included</span>
<span class="c1"># in your css file:</span>
<span class="c1">#</span>
<span class="c1"># Style definition file generated by highlight 2.4.8, http://www.andre-simon.de/</span>
<span class="c1">#</span>
<span class="c1"># table