/*
 * Copyright (C) the libgit2 contributors. All rights reserved.
 *
 * This file is part of libgit2, distributed under the GNU GPL v2 with
 * a Linking Exception. For full terms see the included COPYING file.
 */

#include "common.h"

#include "git2/types.h"
#include "git2/net.h"
#include "git2/repository.h"
#include "git2/object.h"
#include "git2/tag.h"
#include "git2/transport.h"
#include "git2/revwalk.h"
#include "git2/odb_backend.h"
#include "git2/pack.h"
#include "git2/commit.h"
#include "git2/revparse.h"

#include "pack-objects.h"
#include "refs.h"
#include "posix.h"
#include "path.h"
#include "buffer.h"
#include "repository.h"
#include "odb.h"
#include "push.h"
#include "remote.h"
#include "proxy.h"

typedef struct {
	git_transport parent;
	git_remote *owner;
	char *url;
	int direction;
	int flags;
	git_atomic cancelled;
	git_repository *repo;
	git_transport_message_cb progress_cb;
	git_transport_message_cb error_cb;
	void *message_cb_payload;
	git_vector refs;
	unsigned connected : 1,
		have_refs : 1;
} transport_local;

static void free_head(git_remote_head *head)
{
	git__free(head->name);
	git__free(head->symref_target);
	git__free(head);
}

static void free_heads(git_vector *heads)
{
	git_remote_head *head;
	size_t i;

	git_vector_foreach(heads, i, head)
		free_head(head);

	git_vector_free(heads);
}

static int add_ref(transport_local *t, const char *name)
{
	const char peeled[] = "^{}";
	git_reference *ref, *resolved;
	git_remote_head *head;
	git_oid obj_id;
	git_object *obj = NULL, *target = NULL;
	git_buf buf = GIT_BUF_INIT;
	int error;

	if ((error = git_reference_lookup(&ref, t->repo, name)) < 0)
		return error;

	error = git_reference_resolve(&resolved, ref);
	if (error < 0) {
		git_reference_free(ref);
		if (!strcmp(name, GIT_HEAD_FILE) && error == GIT_ENOTFOUND) {
			/* This is actually okay.  Empty repos often have a HEAD that
			 * points to a nonexistent "refs/heads/master". */
			giterr_clear();
			return 0;
		}
		return error;
	}

	git_oid_cpy(&obj_id, git_reference_target(resolved));
	git_reference_free(resolved);

	head = git__calloc(1, sizeof(git_remote_head));
	GITERR_CHECK_ALLOC(head);

	head->name = git__strdup(name);
	GITERR_CHECK_ALLOC(head->name);

	git_oid_cpy(&head->oid, &obj_id);

	if (git_reference_type(ref) == GIT_REF_SYMBOLIC) {
		head->symref_target = git__strdup(git_reference_symbolic_target(ref));
		GITERR_CHECK_ALLOC(head->symref_target);
	}
	git_reference_free(ref);

	if ((error = git_vector_insert(&t->refs, head)) < 0) {
		free_head(head);
		return error;
	}

	/* If it's not a tag, we don't need to try to peel it */
	if (git__prefixcmp(name, GIT_REFS_TAGS_DIR))
		return 0;

	if ((error = git_object_lookup(&obj, t->repo, &head->oid, GIT_OBJ_ANY)) < 0)
		return error;

	head = NULL;

	/* If it's not an annotated tag, or if we're mocking
	 * git-receive-pack, just get out */
	if (git_object_type(obj) != GIT_OBJ_TAG ||
		t->direction != GIT_DIRECTION_FETCH) {
		git_object_free(obj);
		return 0;
	}

	/* And if it's a tag, peel it, and add it to the list */
	head = git__calloc(1, sizeof(git_remote_head));
	GITERR_CHECK_ALLOC(head);

	if (git_buf_join(&buf, 0, name, peeled) < 0) {
		free_head(head);
		return -1;
	}
	head->name = git_buf_detach(&buf);

	if (!(error = git_tag_peel(&target, (git_tag *)obj))) {
		git_oid_cpy(&head->oid, git_object_id(target));

		if ((error = git_vector_insert(&t->refs, head)) < 0) {
			free_head(head);
		}
	}

	git_object_free(obj);
	git_object_free(target);

	return error;
}

static int store_refs(transport_local *t)
{
	size_t i;
	git_remote_head *head;
	git_strarray ref_names = {0};

	assert(t);

	if (git_reference_list(&ref_names, t->repo) < 0)
		goto on_error;

	/* Clear all heads we might have fetched in a previous connect */
	git_vector_foreach(&t->refs, i, head) {
		git__free(head->name);
		git__free(head);
	}

	/* Clear the vector so we can reuse it */
	git_vector_clear(&t->refs);

	/* Sort the references first */
	git__tsort((void **)ref_names.strings, ref_names.count, &git__strcmp_cb);

	/* Add HEAD iff direction is fetch */
	if (t->direction == GIT_DIRECTION_FETCH && add_ref(t, GIT_HEAD_FILE) < 0)
		goto on_error;

	for (i = 0; i < ref_names.count; ++i) {
		if (add_ref(t, ref_names.strings[i]) < 0)
			goto on_error;
	}

	t->have_refs = 1;
	git_strarray_free(&ref_names);
	return 0;

on_error:
	git_vector_free(&t->refs);
	git_strarray_free(&ref_names);
	return -1;
}

/*
 * Try to open the url as a git directory. The direction doesn't
 * matter in this case because we're calculating the heads ourselves.
 */
static int local_connect(
	git_transport *transport,
	const char *url,
	git_cred_acquire_cb cred_acquire_cb,
	void *cred_acquire_payload,
	const git_proxy_options *proxy,
	int direction, int flags)
{
	git_repository *repo;
	int error;
	transport_local *t = (transport_local *) transport;
	const char *path;
	git_buf buf = GIT_BUF_INIT;

	GIT_UNUSED(cred_acquire_cb);
	GIT_UNUSED(cred_acquire_payload);
	GIT_UNUSED(proxy);

	if (t->connected)
		return 0;

	free_heads(&t->refs);

	t->url = git__strdup(url);
	GITERR_CHECK_ALLOC(t->url);
	t->direction = direction;
	t->flags = flags;

	/* 'url' may be a url or path; convert to a path */
	if ((error = git_path_from_url_or_path(&buf, url)) < 0) {
		git_buf_free(&buf);
		return error;
	}
	path = git_buf_cstr(&buf);

	error = git_repository_open(&repo, path);

	git_buf_free(&buf);

	if (error < 0)
		return -1;

	t->repo = repo;

	if (store_refs(t) < 0)
		return -1;

	t->connected = 1;

	return 0;
}

static int local_ls(const git_remote_head ***out, size_t *size, git_transport *transport)
{
	transport_local *t = (transport_local *)transport;

	if (!t->have_refs) {
		giterr_set(GITERR_NET, "the transport has not yet loaded the refs");
		return -1;
	}

	*out = (const git_remote_head **)t->refs.contents;
	*size = t->refs.length;

	return 0;
}

static int local_negotiate_fetch(
	git_transport *transport,
	git_repository *repo,
	const git_remote_head * const *refs,
	size_t count)
{
	transport_local *t = (transport_local*)transport;
	git_remote_head *rhead;
	unsigned int i;

	GIT_UNUSED(refs);
	GIT_UNUSED(count);

	/* Fill in the loids */
	git_vector_foreach(&t->refs, i, rhead) {
		git_object *obj;

		int error = git_revparse_single(&obj, repo, rhead->name);
		if (!error)
			git_oid_cpy(&rhead->loid, git_object_id(obj));
		else if (error != GIT_ENOTFOUND)
			return error;
		else
			giterr_clear();
		git_object_free(obj);
	}

	return 0;
}

static int local_push_update_remote_ref(
	git_repository *remote_repo,
	const char *lref,
	const char *rref,
	git_oid *loid,
	git_oid *roid)
{
	int error;
	git_reference *remote_ref = NULL;

	/* check for lhs, if it's empty it means to delete */
	if (lref[0] != '\0') {
		/* Create or update a ref */
		error = git_reference_create(NULL, remote_repo, rref, loid,
					     !git_oid_iszero(roid), NULL);
	} else {
		/* Delete a ref */
		if ((error = git_reference_lookup(&remote_ref, remote_repo, rref)) < 0) {
			if (error == GIT_ENOTFOUND)
				error = 0;
			return error;
		}

		error = git_reference_delete(remote_ref);
		git_reference_free(remote_ref);
	}

	return error;
}

static int transfer_to_push_transfer(const git_transfer_progress *stats, void *payload)
{
	const git_remote_callbacks *cbs = payload;

	if (!cbs || !cbs->push_transfer_progress)
		return 0;

	return cbs->push_transfer_progress(stats->received_objects, stats->total_objects, stats->received_bytes,
					   cbs->payload);
}

static int local_push(
	git_transport *transport,
	git_push *push,
	const git_remote_callbacks *cbs)
{
	transport_local *t = (transport_local *)transport;
	git_repository *remote_repo = NULL;
	push_spec *spec;
	char *url = NULL;
	const char *path;
	git_buf buf = GIT_BUF_INIT, odb_path = GIT_BUF_INIT;
	int error;
	size_t j;

	GIT_UNUSED(cbs);

	/* 'push->remote->url' may be a url or path; convert to a path */
	if ((error = git_path_from_url_or_path(&buf, push->remote->url)) < 0) {
		git_buf_free(&buf);
		return error;
	}
	path = git_buf_cstr(&buf);

	error = git_repository_open(&remote_repo, path);

	git_buf_free(&buf);

	if (error < 0)
		return error;

	/* We don't currently support pushing locally to non-bare repos. Proper
	   non-bare repo push support would require checking configs to see if
	   we should override the default 'don't let this happen' behavior.

	   Note that this is only an issue when pushing to the current branch,
	   but we forbid all pushes just in case */
	if (!remote_repo->is_bare) {
		error = GIT_EBAREREPO;
		giterr_set(GITERR_INVALID, "local push doesn't (yet) support pushing to non-bare repos.");
		goto on_error;
	}

	if ((error = git_repository_item_path(&odb_path, remote_repo, GIT_REPOSITORY_ITEM_OBJECTS)) < 0
		|| (error = git_buf_joinpath(&odb_path, odb_path.ptr, "pack")) < 0)
		goto on_error;

	error = git_packbuilder_write(push->pb, odb_path.ptr, 0, transfer_to_push_transfer, (void *) cbs);
	git_buf_free(&odb_path);

	if (error < 0)
		goto on_error;

	push->unpack_ok = 1;

	git_vector_foreach(&push->specs, j, spec) {
		push_status *status;
		const git_error *last;
		char *ref = spec->refspec.dst;

		status = git__calloc(1, sizeof(push_status));
		if (!status)
			goto on_error;

		status->ref = git__strdup(ref);
		if (!status->ref) {
			git_push_status_free(status);
			goto on_error;
		}

		error = local_push_update_remote_ref(remote_repo, spec->refspec.src, spec->refspec.dst,
			&spec->loid, &spec->roid);

		switch (error) {
			case GIT_OK:
				break;
			case GIT_EINVALIDSPEC:
				status->msg = git__strdup("funny refname");
				break;
			case GIT_ENOTFOUND:
				status->msg = git__strdup("Remote branch not found to delete");
				break;
			default:
				last = giterr_last();

				if (last && last->message)
					status->msg = git__strdup(last->message);
				else
					status->msg = git__strdup("Unspecified error encountered");
				break;
		}

		/* failed to allocate memory for a status message */
		if (error < 0 && !status->msg) {
			git_push_status_free(status);
			goto on_error;
		}

		/* failed to insert the ref update status */
		if ((error = git_vector_insert(&push->status, status)) < 0) {
			git_push_status_free(status);
			goto on_error;
		}
	}

	if (push->specs.length) {
		int flags = t->flags;
		url = git__strdup(t->url);

		if (!url || t->parent.close(&t->parent) < 0 ||
			t->parent.connect(&t->parent, url,
			NULL, NULL, NULL, GIT_DIRECTION_PUSH, flags))
			goto on_error;
	}

	error = 0;

on_error:
	git_repository_free(remote_repo);
	git__free(url);

	return error;
}

typedef struct foreach_data {
	git_transfer_progress *stats;
	git_transfer_progress_cb progress_cb;
	void *progress_payload;
	git_odb_writepack *writepack;
} foreach_data;

static int foreach_cb(void *buf, size_t len, void *payload)
{
	foreach_data *data = (foreach_data*)payload;

	data->stats->received_bytes += len;
	return data->writepack->append(data->writepack, buf, len, data->stats);
}

static const char *counting_objects_fmt = "Counting objects %d\r";
static const char *compressing_objects_fmt = "Compressing objects: %.0f%% (%d/%d)";

static int local_counting(int stage, unsigned int current, unsigned int total, void *payload)
{
	git_buf progress_info = GIT_BUF_INIT;
	transport_local *t = payload;
	int error;

	if (!t->progress_cb)
		return 0;

	if (stage == GIT_PACKBUILDER_ADDING_OBJECTS) {
		git_buf_printf(&progress_info, counting_objects_fmt, current);
	} else if (stage == GIT_PACKBUILDER_DELTAFICATION) {
		float perc = (((float) current) / total) * 100;
		git_buf_printf(&progress_info, compressing_objects_fmt, perc, current, total);
		if (current == total)
			git_buf_printf(&progress_info, ", done\n");
		else
			git_buf_putc(&progress_info, '\r');

	}

	if (git_buf_oom(&progress_info))
		return -1;

	error = t->progress_cb(git_buf_cstr(&progress_info), git_buf_len(&progress_info), t->message_cb_payload);
	git_buf_free(&progress_info);

	return error;
}

static int foreach_reference_cb(git_reference *reference, void *payload)
{
	git_revwalk *walk = (git_revwalk *)payload;
	int error;

	if (git_reference_type(reference) != GIT_REF_OID)
		return 0;

	error = git_revwalk_hide(walk, git_reference_target(reference));
	/* The reference is in the local repository, so the target may not
	 * exist on the remote.  It also may not be a commit. */
	if (error == GIT_ENOTFOUND || error == GITERR_INVALID) {
		giterr_clear();
		error = 0;
	}

	git_reference_free(reference);

	return error;
}

static int local_download_pack(
		git_transport *transport,
		git_repository *repo,
		git_transfer_progress *stats,
		git_transfer_progress_cb progress_cb,
		void *progress_payload)
{
	transport_local *t = (transport_local*)transport;
	git_revwalk *walk = NULL;
	git_remote_head *rhead;
	unsigned int i;
	int error = -1;
	git_packbuilder *pack = NULL;
	git_odb_writepack *writepack = NULL;
	git_odb *odb = NULL;
	git_buf progress_info = GIT_BUF_INIT;

	if ((error = git_revwalk_new(&walk, t->repo)) < 0)
		goto cleanup;
	git_revwalk_sorting(walk, GIT_SORT_TIME);

	if ((error = git_packbuilder_new(&pack, t->repo)) < 0)
		goto cleanup;

	git_packbuilder_set_callbacks(pack, local_counting, t);

	stats->total_objects = 0;
	stats->indexed_objects = 0;
	stats->received_objects = 0;
	stats->received_bytes = 0;

	git_vector_foreach(&t->refs, i, rhead) {
		git_object *obj;
		if ((error = git_object_lookup(&obj, t->repo, &rhead->oid, GIT_OBJ_ANY)) < 0)
			goto cleanup;

		if (git_object_type(obj) == GIT_OBJ_COMMIT) {
			/* Revwalker includes only wanted commits */
			error = git_revwalk_push(walk, &rhead->oid);
		} else {
			/* Tag or some other wanted object. Add it on its own */
			error = git_packbuilder_insert_recur(pack, &rhead->oid, rhead->name);
		}
		git_object_free(obj);
		if (error < 0)
			goto cleanup;
	}

	if ((error = git_reference_foreach(repo, foreach_reference_cb, walk)))
		goto cleanup;

	if ((error = git_packbuilder_insert_walk(pack, walk)))
		goto cleanup;

	if ((error = git_buf_printf(&progress_info, counting_objects_fmt, git_packbuilder_object_count(pack))) < 0)
		goto cleanup;

	if (t->progress_cb &&
	    (error = t->progress_cb(git_buf_cstr(&progress_info), git_buf_len(&progress_info), t->message_cb_payload)) < 0)
		goto cleanup;

	/* Walk the objects, building a packfile */
	if ((error = git_repository_odb__weakptr(&odb, repo)) < 0)
		goto cleanup;

	/* One last one with the newline */
	git_buf_clear(&progress_info);
	git_buf_printf(&progress_info, counting_objects_fmt, git_packbuilder_object_count(pack));
	if ((error = git_buf_putc(&progress_info, '\n')) < 0)
		goto cleanup;

	if (t->progress_cb &&
	    (error = t->progress_cb(git_buf_cstr(&progress_info), git_buf_len(&progress_info), t->message_cb_payload)) < 0)
		goto cleanup;

	if ((error = git_odb_write_pack(&writepack, odb, progress_cb, progress_payload)) != 0)
		goto cleanup;

	/* Write the data to the ODB */
	{
		foreach_data data = {0};
		data.stats = stats;
		data.progress_cb = progress_cb;
		data.progress_payload = progress_payload;
		data.writepack = writepack;

		/* autodetect */
		git_packbuilder_set_threads(pack, 0);

		if ((error = git_packbuilder_foreach(pack, foreach_cb, &data)) != 0)
			goto cleanup;
	}

	error = writepack->commit(writepack, stats);

cleanup:
	if (writepack) writepack->free(writepack);
	git_buf_free(&progress_info);
	git_packbuilder_free(pack);
	git_revwalk_free(walk);
	return error;
}

static int local_set_callbacks(
	git_transport *transport,
	git_transport_message_cb progress_cb,
	git_transport_message_cb error_cb,
	git_transport_certificate_check_cb certificate_check_cb,
	void *message_cb_payload)
{
	transport_local *t = (transport_local *)transport;

	GIT_UNUSED(certificate_check_cb);

	t->progress_cb = progress_cb;
	t->error_cb = error_cb;
	t->message_cb_payload = message_cb_payload;

	return 0;
}

static int local_is_connected(git_transport *transport)
{
	transport_local *t = (transport_local *)transport;

	return t->connected;
}

static int local_read_flags(git_transport *transport, int *flags)
{
	transport_local *t = (transport_local *)transport;

	*flags = t->flags;

	return 0;
}

static void local_cancel(git_transport *transport)
{
	transport_local *t = (transport_local *)transport;

	git_atomic_set(&t->cancelled, 1);
}

static int local_close(git_transport *transport)
{
	transport_local *t = (transport_local *)transport;

	t->connected = 0;

	if (t->repo) {
		git_repository_free(t->repo);
		t->repo = NULL;
	}

	if (t->url) {
		git__free(t->url);
		t->url = NULL;
	}

	return 0;
}

static void local_free(git_transport *transport)
{
	transport_local *t = (transport_local *)transport;

	free_heads(&t->refs);

	/* Close the transport, if it's still open. */
	local_close(transport);

	/* Free the transport */
	git__free(t);
}

/**************
 * Public API *
 **************/

int git_transport_local(git_transport **out, git_remote *owner, void *param)
{
	int error;
	transport_local *t;

	GIT_UNUSED(param);

	t = git__calloc(1, sizeof(transport_local));
	GITERR_CHECK_ALLOC(t);

	t->parent.version = GIT_TRANSPORT_VERSION;
	t->parent.set_callbacks = local_set_callbacks;
	t->parent.connect = local_connect;
	t->parent.negotiate_fetch = local_negotiate_fetch;
	t->parent.download_pack = local_download_pack;
	t->parent.push = local_push;
	t->parent.close = local_close;
	t->parent.free = local_free;
	t->parent.ls = local_ls;
	t->parent.is_connected = local_is_connected;
	t->parent.read_flags = local_read_flags;
	t->parent.cancel = local_cancel;

	if ((error = git_vector_init(&t->refs, 0, NULL)) < 0) {
		git__free(t);
		return error;
	}

	t->owner = owner;

	*out = (git_transport *) t;

	return 0;
}
