/* ui-clone.c: functions for http cloning, based on
 * git's http-backend.c by Shawn O. Pearce
 *
 * 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-clone.h"
#include "html.h"
#include "ui-shared.h"

static int print_ref_info(const char *refname, const unsigned char *sha1,
                          int flags, void *cb_data)
{
	struct object *obj;

	if (!(obj = parse_object(sha1)))
		return 0;

	htmlf("%s\t%s\n", sha1_to_hex(sha1), refname);
	if (obj->type == OBJ_TAG) {
		if (!(obj = deref_tag(obj, refname, 0)))
			return 0;
		htmlf("%s\t%s^{}\n", sha1_to_hex(obj->sha1), refname);
	}
	return 0;
}

static void print_pack_info(void)
{
	struct packed_git *pack;
	int ofs;

	ctx.page.mimetype = "text/plain";
	ctx.page.filename = "objects/info/packs";
	cgit_print_http_headers();
	ofs = strlen(ctx.repo->path) + strlen("/objects/pack/");
	prepare_packed_git();
	for (pack = packed_git; pack; pack = pack->next)
		if (pack->pack_local)
			htmlf("P %s\n", pack->pack_name + ofs);
}

static void send_file(char *path)
{
	struct stat st;

	if (stat(path, &st)) {
		switch (errno) {
		case ENOENT:
			html_status(404, "Not found", 0);
			break;
		case EACCES:
			html_status(403, "Forbidden", 0);
			break;
		default:
			html_status(400, "Bad request", 0);
		}
		return;
	}
	ctx.page.mimetype = "application/octet-stream";
	ctx.page.filename = path;
	if (!starts_with(ctx.repo->path, path))
		ctx.page.filename += strlen(ctx.repo->path) + 1;
	cgit_print_http_headers();
	html_include(path);
}

static void dispatch_to_git_http_backend(void)
{
	if (access(ctx.cfg.http_backend_path, X_OK) != -1) {
		size_t git_root_len;
		char *git_root = NULL;

		/* git-http-backend does it's own URL parsing and concatenates
		 * GIT_PROJECT_ROOT and PATH_INFO to find the git repo.
		 * The root is the same as scan-path, but scan-path is not
		 * always available so we calculate the root path.
		 * Example:
		 *   repo.path   = /srv/git/some/more/dirs/
		 *   qry.repo    = some/more/dirs
		 *   -> git_root = /srv/git/
		 */
		strip_suffix(ctx.repo->path, "/", &git_root_len);
		strip_suffix_mem(ctx.repo->path, &git_root_len, ctx.qry.repo);

		git_root = xmalloc(git_root_len + 1);
		strncpy(git_root, ctx.repo->path, git_root_len);
		git_root[git_root_len] = '\0';

		setenv("GIT_PROJECT_ROOT", git_root, 1);
		execl(ctx.cfg.http_backend_path, "git-http-backend", NULL);
	} else {
		fprintf(stderr, "[cgit] http-backend-path (%s) is not executable: %s\n",
			ctx.cfg.http_backend_path, strerror(errno));
		html_status(500, "Internal Server Error", 0);
	}
}

void cgit_clone_info(void)
{
	if (ctx.cfg.http_backend_path) {
		return dispatch_to_git_http_backend();
	}

	if (!ctx.qry.path || strcmp(ctx.qry.path, "refs"))
		return;

	ctx.page.mimetype = "text/plain";
	ctx.page.filename = "info/refs";
	cgit_print_http_headers();
	for_each_ref(print_ref_info, NULL);
}

void cgit_clone_objects(void)
{
	if (ctx.cfg.http_backend_path) {
		return dispatch_to_git_http_backend();
	}

	if (!ctx.qry.path) {
		html_status(400, "Bad request", 0);
		return;
	}

	if (!strcmp(ctx.qry.path, "info/packs")) {
		print_pack_info();
		return;
	}

	send_file(git_path("objects/%s", ctx.qry.path));
}

void cgit_clone_head(void)
{
	if (ctx.cfg.http_backend_path) {
		return dispatch_to_git_http_backend();
	}

	send_file(git_path("%s", "HEAD"));
}

void cgit_clone_git_upload_pack(void)
{
	if (ctx.cfg.http_backend_path) {
		return dispatch_to_git_http_backend();
	}

	html_status(404, "Not found", 0);
}

void cgit_clone_git_receive_pack(void)
{
	if (ctx.cfg.http_backend_path) {
		return dispatch_to_git_http_backend();
	}

	html_status(404, "Not found", 0);
}