/*
 * The branch and tag listings, shown as sections of the summary page and as
 * the whole of a repository's refs page. Every row is one ref beside
 * the commit or tag object it points at, ordered newest first, with branches
 * then reordered by name unless branch-sort asks for age. A section longer
 * than max-ref-count is cut short and ends in a link to a dedicated heads or
 * tags page, which walks the same list one offset at a time.
 */

#define USE_THE_REPOSITORY_VARIABLE

#include "cgit.h"
#include "filter.h"
#include "html.h"
#include "shared.h"
#include "ui-refs.h"
#include "ui-shared.h"

// The slice of a sorted ref list that one page shows, with end one past the
// last row. size is what a full page holds, so it also decides whether the
// list needs a pager.
struct ref_page {
	int size;
	int start;
	int end;
};

/*
 * The tagger date and the committer date live in a union in struct refinfo and
 * only the member matching the object type is ever filled, so assuming a ref
 * points at a commit reads past the end of the smaller struct.
 */
static timestamp_t ref_date(struct refinfo *ref)
{
	if (!ref->object)
		return 0;
	switch (ref->object->type) {
	case OBJ_TAG:
		return ref->tag ? ref->tag->tagger_date : 0;
	case OBJ_COMMIT:
		return ref->commit ? ref->commit->committer_date : 0;
	}
	return 0;
}

static int cmp_date(const void *a, const void *b)
{
	struct refinfo *ref1 = *(struct refinfo **)a;
	struct refinfo *ref2 = *(struct refinfo **)b;
	timestamp_t date1 = ref_date(ref1), date2 = ref_date(ref2);

	// Compared rather than subtracted, at the width the dates are stored
	// at. A commit may carry any timestamp, so a difference that does not
	// fit an int would leave qsort with a contradictory ordering.
	if (date1 < date2)
		return 1;
	if (date1 > date2)
		return -1;
	return 0;
}

static int cmp_name(const void *a, const void *b)
{
	struct refinfo *ref1 = *(struct refinfo **)a;
	struct refinfo *ref2 = *(struct refinfo **)b;

	return strcmp(ref1->refname, ref2->refname);
}

static void collect_branches(struct reflist *list)
{
	list->refs = NULL;
	list->alloc = list->count = 0;
	refs_for_each_branch_ref(get_main_ref_store(the_repository), cgit_refs_cb, list);
	if (ctx.repo->enable_remote_branches)
		refs_for_each_remote_ref(get_main_ref_store(the_repository), cgit_refs_cb, list);
}

static void print_branch_header(void)
{
	html(
		"<tbody class='branches'>\n"
		"<tr class='nohover'><th class='left' scope='col'>Branch</th>"
		"<th class='left' scope='col'>Commit message</th>"
		"<th class='left col-author' scope='col'>Author</th>"
		"<th colspan='2' class='left' scope='col'>Age</th></tr>\n"
	);
}

static int print_branch(struct refinfo *ref)
{
	struct commitinfo *info = ref->commit;
	const char *name = ref->refname;

	if (!info)
		return 1;
	html("<tr class='branch'><td>");
	cgit_log_link(name, NULL, NULL, name, NULL, NULL, 0, NULL, NULL, ctx.qry.showmsg, 0);
	html("</td><td>");

	if (ref->object->type == OBJ_COMMIT) {
		cgit_commit_link(info->subject, NULL, NULL, name, NULL, NULL);
		html("</td><td class='col-author'>");
		// A filter must not be handed a NULL argument.
		cgit_open_filter(
			ctx.repo->email_filter, info->author_email ? info->author_email : "", "refs"
		);
		html_txt(info->author);
		cgit_close_filter(ctx.repo->email_filter);
		html("</td><td colspan='2'>");
		cgit_print_age(info->committer_date, info->committer_tz, -1);
	} else {
		// The object link sits in the message column, and the empty
		// tail cells keep the row as wide as the header.
		cgit_object_link(ref->object, 0);
		html("</td><td class='col-author'></td><td colspan='2'>");
	}
	html("</td></tr>\n");
	return 0;
}

static void collect_tags(struct reflist *list)
{
	list->refs = NULL;
	list->alloc = list->count = 0;
	refs_for_each_tag_ref(get_main_ref_store(the_repository), cgit_refs_cb, list);
}

static void print_tag_header(void)
{
	html(
		"<tbody class='tags'>\n"
		"<tr class='nohover'><th class='left' scope='col'>Tag</th>"
		"<th class='left' scope='col'>Download</th>"
		"<th class='left col-author' scope='col'>Author</th>"
		"<th colspan='2' class='left' scope='col'>Age</th></tr>\n"
	);
}

static int print_tag(struct refinfo *ref)
{
	struct taginfo *info = NULL;
	const char *name = ref->refname;
	struct object *obj = ref->object;

	// A lightweight tag has no tag object, so the author and age columns
	// below fall back to the commit.
	if (obj->type == OBJ_TAG) {
		struct tag *tag = (struct tag *)obj;

		obj = tag->tagged;
		info = ref->tag;
		if (!info)
			return 1;
	}

	html("<tr class='tag'><td>");
	cgit_tag_link(name, NULL, NULL, name);
	html("</td><td>");
	if (ctx.repo->snapshots && (obj->type == OBJ_COMMIT))
		cgit_print_snapshot_links(ctx.repo, name, " ");
	else
		cgit_object_link(obj, 0);
	html("</td><td class='col-author'>");
	if (info) {
		if (info->tagger) {
			cgit_open_filter(ctx.repo->email_filter, info->tagger_email, "refs");
			html_txt(info->tagger);
			cgit_close_filter(ctx.repo->email_filter);
		}
	} else if (ref->object->type == OBJ_COMMIT) {
		cgit_open_filter(
			ctx.repo->email_filter, ref->commit->author_email ? ref->commit->author_email : "",
			"refs"
		);
		html_txt(ref->commit->author);
		cgit_close_filter(ctx.repo->email_filter);
	}
	html("</td><td colspan='2'>");
	if (info) {
		if (info->tagger_date > 0)
			cgit_print_age(info->tagger_date, info->tagger_tz, -1);
	} else if (ref->object->type == OBJ_COMMIT) {
		cgit_print_age(ref->commit->commit->date, 0, -1);
	}
	html("</td></tr>\n");

	return 0;
}

static void print_refs_link(const char *path)
{
	html("<tr class='nohover'><td colspan='5'>");
	cgit_refs_link("[...]", NULL, NULL, ctx.qry.head, NULL, path);
	html("</td></tr>\n");
}

static void print_ref_pager(int ofs, int pagesize, int count, const char *path)
{
	char *url;

	html("<tr class='nohover'><td colspan='5' class='refs-pager'>");
	if (ofs > 0) {
		int prev_ofs = ofs > pagesize ? ofs - pagesize : 0;

		url = cgit_pageurl(ctx.qry.repo, cgit_fmt("refs/%s", path), cgit_fmt("ofs=%d", prev_ofs));
		html("<a href='");
		html_attr(url);
		html("'>[prev]</a> ");
		free(url);
	}
	htmlf("%d - %d of %d", ofs + 1, ofs + pagesize < count ? ofs + pagesize : count, count);
	if (ofs + pagesize < count) {
		url = cgit_pageurl(ctx.qry.repo, cgit_fmt("refs/%s", path),
			cgit_fmt("ofs=%d", ofs + pagesize));
		html(" <a href='");
		html_attr(url);
		html("'>[next]</a>");
		free(url);
	}
	html("</td></tr>\n");
}

static struct ref_page page_bounds(int pagesize, int count)
{
	struct ref_page page;

	page.size = (pagesize <= 0 || pagesize > count) ? count : pagesize;
	page.start = ctx.qry.ofs > 0 ? ctx.qry.ofs : 0;
	if (page.start > count)
		page.start = count;
	page.end = page.start + page.size < count ? page.start + page.size : count;
	return page;
}

/*
 * Unlike the capped sections, the whole list is sorted before a page is cut
 * out of it, so a branch keeps its place no matter which page it lands on.
 */
static void print_branches_page(int pagesize)
{
	struct reflist list;
	struct ref_page page;
	int i;

	print_branch_header();
	collect_branches(&list);

	qsort(list.refs, list.count, sizeof(*list.refs), cmp_date);
	if (ctx.repo->branch_sort == 0)
		qsort(list.refs, list.count, sizeof(*list.refs), cmp_name);

	page = page_bounds(pagesize, list.count);

	for (i = page.start; i < page.end; i++)
		print_branch(list.refs[i]);

	if (page.size < list.count)
		print_ref_pager(page.start, page.size, list.count, "heads");
	html("</tbody>\n");

	cgit_free_reflist_inner(&list);
}

static void print_tags_page(int pagesize)
{
	struct reflist list;
	struct ref_page page;
	int i;

	collect_tags(&list);
	if (list.count == 0)
		return;
	qsort(list.refs, list.count, sizeof(*list.refs), cmp_date);

	page = page_bounds(pagesize, list.count);

	print_tag_header();
	for (i = page.start; i < page.end; i++)
		print_tag(list.refs[i]);

	if (page.size < list.count)
		print_ref_pager(page.start, page.size, list.count, "tags");
	html("</tbody>\n");

	cgit_free_reflist_inner(&list);
}

void cgit_print_branches(int maxcount)
{
	struct reflist list;
	int i;

	print_branch_header();
	collect_branches(&list);

	if (maxcount == 0 || maxcount > list.count)
		maxcount = list.count;

	// The date sort covers the list, the name sort only the rows about to
	// be shown, so the section holds the newest branches rather than the
	// first ones by name.
	qsort(list.refs, list.count, sizeof(*list.refs), cmp_date);
	if (ctx.repo->branch_sort == 0)
		qsort(list.refs, maxcount, sizeof(*list.refs), cmp_name);

	for (i = 0; i < maxcount; i++)
		print_branch(list.refs[i]);

	if (maxcount < list.count)
		print_refs_link("heads");
	html("</tbody>\n");

	cgit_free_reflist_inner(&list);
}

void cgit_print_tags(int maxcount)
{
	struct reflist list;
	int i;

	collect_tags(&list);
	if (list.count == 0)
		return;
	qsort(list.refs, list.count, sizeof(*list.refs), cmp_date);
	if (!maxcount)
		maxcount = list.count;
	else if (maxcount > list.count)
		maxcount = list.count;
	print_tag_header();
	for (i = 0; i < maxcount; i++)
		print_tag(list.refs[i]);

	if (maxcount < list.count)
		print_refs_link("tags");
	html("</tbody>\n");

	cgit_free_reflist_inner(&list);
}

void cgit_print_refs(void)
{
	cgit_print_layout_start();
	html("<table class='list refs' aria-label='Branches and tags'>\n");

	if (ctx.qry.path && starts_with(ctx.qry.path, "heads")) {
		print_branches_page(ctx.cfg.max_ref_count);
	} else if (ctx.qry.path && starts_with(ctx.qry.path, "tags")) {
		print_tags_page(ctx.cfg.max_ref_count);
	} else {
		cgit_print_branches(ctx.cfg.max_ref_count);
		cgit_print_tags(ctx.cfg.max_ref_count);
	}
	html("</table>\n");
	cgit_print_layout_end();
}