/*
 * Copyright (c) 2017 Martin Pieuchot
 *
 * 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.
 */

#include <err.h>
#include <errno.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <git2.h>

#ifndef nitems
#define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
#endif

struct cmd {
	const char	 *cmd_name;
	int		(*cmd_main)(int, char *[]);
};

__dead void	usage(void);

int		cmd_log(int, char *[]);
int		cmd_status(int, char *[]);

struct cmd got_commands[] = {
	{ "log",	cmd_log },
	{ "status",	cmd_status },
};

int
main(int argc, char *argv[])
{
	struct cmd *cmd;
	unsigned int i;
	int ch;

	setlocale(LC_ALL, "");

	if (pledge("stdio rpath", NULL) == -1)
		err(1, "pledge");

	while ((ch = getopt(argc, argv, "")) != -1) {
		switch (ch) {
		default:
			usage();
			/* NOTREACHED */
		}
	}

	argc -= optind;
	argv += optind;

	if (argc <= 0)
		usage();

	for (i = 0; i < nitems(got_commands); i++) {
		cmd = &got_commands[i];

		if (strncmp(cmd->cmd_name, argv[0], strlen(argv[0])))
			continue;

		return got_commands[i].cmd_main(argc, argv);
		/* NOTREACHED */
	}

	fprintf(stderr, "%s: unknown command -- %s\n", getprogname(), argv[0]);
	return 1;
}

__dead void
usage(void)
{
	fprintf(stderr, "usage: %s command [arg ...]\n", getprogname());
	exit(1);
}

int
cmd_log(int argc __unused, char *argv[] __unused)
{
	git_repository *repo = NULL;
	git_revwalk *walker = NULL;
	git_commit *commit = NULL;
	git_oid oid;

	git_libgit2_init();

	if (git_repository_open_ext(&repo, ".", 0, NULL))
		errx(1, "git_repository_open: %s", giterr_last()->message);

	if (git_revwalk_new(&walker, repo))
		errx(1, "git_revwalk_new: %s", giterr_last()->message);

	if (git_revwalk_push_head(walker))
		errx(1, "git_revwalk_push_head: %s", giterr_last()->message);

	while (git_revwalk_next(&oid, walker) == 0) {
		char buf[GIT_OID_HEXSZ + 1];
		const git_signature *sig;

		git_commit_free(commit);
		if (git_commit_lookup(&commit, repo, &oid))
			errx(1, "git_commit_lookup: %s", giterr_last()->message);

		printf("-----------------------------------------------\n");
		git_oid_tostr(buf, sizeof(buf), git_commit_id(commit));
		printf("commit %s\n", buf);

		if ((sig = git_commit_author(commit)) != NULL) {
			printf("Author: %s <%s>\n", sig->name, sig->email);
		}
		printf("\n%s\n", git_commit_message_raw(commit));
	}
	git_commit_free(commit);

	git_repository_free(repo);
	git_libgit2_shutdown();

	return 0;
}

int
cmd_status(int argc __unused, char *argv[] __unused)
{
	git_repository *repo = NULL;
	git_status_list *status;
	git_status_options statusopts;
	size_t i;

	git_libgit2_init();

	if (git_repository_open_ext(&repo, ".", 0, NULL))
		errx(1, "git_repository_open: %s", giterr_last()->message);

	if (git_repository_is_bare(repo))
		errx(1, "bar repository");

	if (git_status_init_options(&statusopts, GIT_STATUS_OPTIONS_VERSION))
		errx(1, "git_status_init_options: %s", giterr_last()->message);

	statusopts.show  = GIT_STATUS_SHOW_INDEX_AND_WORKDIR;
	statusopts.flags = GIT_STATUS_OPT_INCLUDE_UNTRACKED |
	    GIT_STATUS_OPT_RENAMES_HEAD_TO_INDEX |
	    GIT_STATUS_OPT_SORT_CASE_SENSITIVELY;

	if (git_status_list_new(&status, repo, &statusopts))
		errx(1, "git_status_list_new: %s", giterr_last()->message);

	for (i = 0; i < git_status_list_entrycount(status); i++) {
		const git_status_entry *se;

		se = git_status_byindex(status, i);
		switch (se->status) {
		case GIT_STATUS_WT_NEW:
			printf("? %s\n", se->index_to_workdir->new_file.path);
			break;
		case GIT_STATUS_WT_MODIFIED:
			printf("M %s\n", se->index_to_workdir->new_file.path);
			break;
		case GIT_STATUS_WT_DELETED:
			printf("R %s\n", se->index_to_workdir->new_file.path);
			break;
		case GIT_STATUS_WT_RENAMED:
			printf("m %s -> %s\n",
			    se->index_to_workdir->old_file.path,
			    se->index_to_workdir->new_file.path);
			break;
		case GIT_STATUS_WT_TYPECHANGE:
			printf("t %s\n", se->index_to_workdir->new_file.path);
			break;
		case GIT_STATUS_INDEX_NEW:
			printf("A %s\n", se->head_to_index->new_file.path);
			break;
		case GIT_STATUS_INDEX_MODIFIED:
			printf("M %s\n", se->head_to_index->old_file.path);
			break;
		case GIT_STATUS_INDEX_DELETED:
			printf("R %s\n", se->head_to_index->old_file.path);
			break;
		case GIT_STATUS_INDEX_RENAMED:
			printf("m %s -> %s\n",
			    se->head_to_index->old_file.path,
			    se->head_to_index->new_file.path);
			break;
		case GIT_STATUS_INDEX_TYPECHANGE:
			printf("t %s\n", se->head_to_index->old_file.path);
			break;
		case GIT_STATUS_CURRENT:
		default:
			break;
		}
	}

	git_status_list_free(status);
	git_repository_free(repo);
	git_libgit2_shutdown();

	return 0;
}