/*
 * 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 "commit.h"
#include "tag.h"
#include "signature.h"
#include "message.h"
#include "git2/object.h"
#include "git2/repository.h"
#include "git2/signature.h"
#include "git2/odb_backend.h"

void git_tag__free(void *_tag)
{
	git_tag *tag = _tag;
	git_signature_free(tag->tagger);
	git__free(tag->message);
	git__free(tag->tag_name);
	git__free(tag);
}

int git_tag_target(git_object **target, const git_tag *t)
{
	assert(t);
	return git_object_lookup(target, t->object.repo, &t->target, t->type);
}

const git_oid *git_tag_target_id(const git_tag *t)
{
	assert(t);
	return &t->target;
}

git_otype git_tag_target_type(const git_tag *t)
{
	assert(t);
	return t->type;
}

const char *git_tag_name(const git_tag *t)
{
	assert(t);
	return t->tag_name;
}

const git_signature *git_tag_tagger(const git_tag *t)
{
	return t->tagger;
}

const char *git_tag_message(const git_tag *t)
{
	assert(t);
	return t->message;
}

static int tag_error(const char *str)
{
	giterr_set(GITERR_TAG, "failed to parse tag: %s", str);
	return -1;
}

static int tag_parse(git_tag *tag, const char *buffer, const char *buffer_end)
{
	static const char *tag_types[] = {
		NULL, "commit\n", "tree\n", "blob\n", "tag\n"
	};
	size_t text_len, alloc_len;
	const char *search;
	unsigned int i;

	if (git_oid__parse(&tag->target, &buffer, buffer_end, "object ") < 0)
		return tag_error("object field invalid");

	if (buffer + 5 >= buffer_end)
		return tag_error("object too short");

	if (memcmp(buffer, "type ", 5) != 0)
		return tag_error("type field not found");
	buffer += 5;

	tag->type = GIT_OBJ_BAD;

	for (i = 1; i < ARRAY_SIZE(tag_types); ++i) {
		size_t type_length = strlen(tag_types[i]);

		if (buffer + type_length >= buffer_end)
			return tag_error("object too short");

		if (memcmp(buffer, tag_types[i], type_length) == 0) {
			tag->type = i;
			buffer += type_length;
			break;
		}
	}

	if (tag->type == GIT_OBJ_BAD)
		return tag_error("invalid object type");

	if (buffer + 4 >= buffer_end)
		return tag_error("object too short");

	if (memcmp(buffer, "tag ", 4) != 0)
		return tag_error("tag field not found");

	buffer += 4;

	search = memchr(buffer, '\n', buffer_end - buffer);
	if (search == NULL)
		return tag_error("object too short");

	text_len = search - buffer;

	GITERR_CHECK_ALLOC_ADD(&alloc_len, text_len, 1);
	tag->tag_name = git__malloc(alloc_len);
	GITERR_CHECK_ALLOC(tag->tag_name);

	memcpy(tag->tag_name, buffer, text_len);
	tag->tag_name[text_len] = '\0';

	buffer = search + 1;

	tag->tagger = NULL;
	if (buffer < buffer_end && *buffer != '\n') {
		tag->tagger = git__malloc(sizeof(git_signature));
		GITERR_CHECK_ALLOC(tag->tagger);

		if (git_signature__parse(tag->tagger, &buffer, buffer_end, "tagger ", '\n') < 0)
			return -1;
	}

	tag->message = NULL;
	if (buffer < buffer_end) {
		/* If we're not at the end of the header, search for it */
		if(*buffer != '\n') {
			search = git__memmem(buffer, buffer_end - buffer,
					     "\n\n", 2);
			if (search)
				buffer = search + 1;
			else
				return tag_error("tag contains no message");
		}

		text_len = buffer_end - ++buffer;

		GITERR_CHECK_ALLOC_ADD(&alloc_len, text_len, 1);
		tag->message = git__malloc(alloc_len);
		GITERR_CHECK_ALLOC(tag->message);

		memcpy(tag->message, buffer, text_len);
		tag->message[text_len] = '\0';
	}

	return 0;
}

int git_tag__parse(void *_tag, git_odb_object *odb_obj)
{
	git_tag *tag = _tag;
	const char *buffer = git_odb_object_data(odb_obj);
	const char *buffer_end = buffer + git_odb_object_size(odb_obj);

	return tag_parse(tag, buffer, buffer_end);
}

static int retrieve_tag_reference(
	git_reference **tag_reference_out,
	git_buf *ref_name_out,
	git_repository *repo,
	const char *tag_name)
{
	git_reference *tag_ref;
	int error;

	*tag_reference_out = NULL;

	if (git_buf_joinpath(ref_name_out, GIT_REFS_TAGS_DIR, tag_name) < 0)
		return -1;

	error = git_reference_lookup(&tag_ref, repo, ref_name_out->ptr);
	if (error < 0)
		return error; /* Be it not foundo or corrupted */

	*tag_reference_out = tag_ref;

	return 0;
}

static int retrieve_tag_reference_oid(
	git_oid *oid,
	git_buf *ref_name_out,
	git_repository *repo,
	const char *tag_name)
{
	if (git_buf_joinpath(ref_name_out, GIT_REFS_TAGS_DIR, tag_name) < 0)
		return -1;

	return git_reference_name_to_id(oid, repo, ref_name_out->ptr);
}

static int write_tag_annotation(
		git_oid *oid,
		git_repository *repo,
		const char *tag_name,
		const git_object *target,
		const git_signature *tagger,
		const char *message)
{
	git_buf tag = GIT_BUF_INIT;
	git_odb *odb;

	git_oid__writebuf(&tag, "object ", git_object_id(target));
	git_buf_printf(&tag, "type %s\n", git_object_type2string(git_object_type(target)));
	git_buf_printf(&tag, "tag %s\n", tag_name);
	git_signature__writebuf(&tag, "tagger ", tagger);
	git_buf_putc(&tag, '\n');

	if (git_buf_puts(&tag, message) < 0)
		goto on_error;

	if (git_repository_odb__weakptr(&odb, repo) < 0)
		goto on_error;

	if (git_odb_write(oid, odb, tag.ptr, tag.size, GIT_OBJ_TAG) < 0)
		goto on_error;

	git_buf_free(&tag);
	return 0;

on_error:
	git_buf_free(&tag);
	giterr_set(GITERR_OBJECT, "failed to create tag annotation");
	return -1;
}

static int git_tag_create__internal(
		git_oid *oid,
		git_repository *repo,
		const char *tag_name,
		const git_object *target,
		const git_signature *tagger,
		const char *message,
		int allow_ref_overwrite,
		int create_tag_annotation)
{
	git_reference *new_ref = NULL;
	git_buf ref_name = GIT_BUF_INIT;

	int error;

	assert(repo && tag_name && target);
	assert(!create_tag_annotation || (tagger && message));

	if (git_object_owner(target) != repo) {
		giterr_set(GITERR_INVALID, "the given target does not belong to this repository");
		return -1;
	}

	error = retrieve_tag_reference_oid(oid, &ref_name, repo, tag_name);
	if (error < 0 && error != GIT_ENOTFOUND)
		goto cleanup;

	/** Ensure the tag name doesn't conflict with an already existing
	 *	reference unless overwriting has explicitly been requested **/
	if (error == 0 && !allow_ref_overwrite) {
		git_buf_free(&ref_name);
		giterr_set(GITERR_TAG, "tag already exists");
		return GIT_EEXISTS;
	}

	if (create_tag_annotation) {
		if (write_tag_annotation(oid, repo, tag_name, target, tagger, message) < 0)
			return -1;
	} else
		git_oid_cpy(oid, git_object_id(target));

	error = git_reference_create(&new_ref, repo, ref_name.ptr, oid, allow_ref_overwrite, NULL);

cleanup:
	git_reference_free(new_ref);
	git_buf_free(&ref_name);
	return error;
}

int git_tag_create(
	git_oid *oid,
	git_repository *repo,
	const char *tag_name,
	const git_object *target,
	const git_signature *tagger,
	const char *message,
	int allow_ref_overwrite)
{
	return git_tag_create__internal(oid, repo, tag_name, target, tagger, message, allow_ref_overwrite, 1);
}

int git_tag_annotation_create(
	git_oid *oid,
	git_repository *repo,
	const char *tag_name,
	const git_object *target,
	const git_signature *tagger,
	const char *message)
{
	assert(oid && repo && tag_name && target && tagger && message);

	return write_tag_annotation(oid, repo, tag_name, target, tagger, message);
}

int git_tag_create_lightweight(
	git_oid *oid,
	git_repository *repo,
	const char *tag_name,
	const git_object *target,
	int allow_ref_overwrite)
{
	return git_tag_create__internal(oid, repo, tag_name, target, NULL, NULL, allow_ref_overwrite, 0);
}

int git_tag_create_frombuffer(git_oid *oid, git_repository *repo, const char *buffer, int allow_ref_overwrite)
{
	git_tag tag;
	int error;
	git_odb *odb;
	git_odb_stream *stream;
	git_odb_object *target_obj;

	git_reference *new_ref = NULL;
	git_buf ref_name = GIT_BUF_INIT;

	assert(oid && buffer);

	memset(&tag, 0, sizeof(tag));

	if (git_repository_odb__weakptr(&odb, repo) < 0)
		return -1;

	/* validate the buffer */
	if (tag_parse(&tag, buffer, buffer + strlen(buffer)) < 0)
		return -1;

	/* validate the target */
	if (git_odb_read(&target_obj, odb, &tag.target) < 0)
		goto on_error;

	if (tag.type != target_obj->cached.type) {
		giterr_set(GITERR_TAG, "the type for the given target is invalid");
		goto on_error;
	}

	error = retrieve_tag_reference_oid(oid, &ref_name, repo, tag.tag_name);
	if (error < 0 && error != GIT_ENOTFOUND)
		goto on_error;

	/* We don't need these objects after this */
	git_signature_free(tag.tagger);
	git__free(tag.tag_name);
	git__free(tag.message);
	git_odb_object_free(target_obj);

	/** Ensure the tag name doesn't conflict with an already existing
	 *	reference unless overwriting has explicitly been requested **/
	if (error == 0 && !allow_ref_overwrite) {
		giterr_set(GITERR_TAG, "tag already exists");
		return GIT_EEXISTS;
	}

	/* write the buffer */
	if ((error = git_odb_open_wstream(
			&stream, odb, strlen(buffer), GIT_OBJ_TAG)) < 0)
		return error;

	if (!(error = git_odb_stream_write(stream, buffer, strlen(buffer))))
		error = git_odb_stream_finalize_write(oid, stream);

	git_odb_stream_free(stream);

	if (error < 0) {
		git_buf_free(&ref_name);
		return error;
	}

	error = git_reference_create(
		&new_ref, repo, ref_name.ptr, oid, allow_ref_overwrite, NULL);

	git_reference_free(new_ref);
	git_buf_free(&ref_name);

	return error;

on_error:
	git_signature_free(tag.tagger);
	git__free(tag.tag_name);
	git__free(tag.message);
	git_odb_object_free(target_obj);
	return -1;
}

int git_tag_delete(git_repository *repo, const char *tag_name)
{
	git_reference *tag_ref;
	git_buf ref_name = GIT_BUF_INIT;
	int error;

	error = retrieve_tag_reference(&tag_ref, &ref_name, repo, tag_name);

	git_buf_free(&ref_name);

	if (error < 0)
		return error;

	error = git_reference_delete(tag_ref);

	git_reference_free(tag_ref);

	return error;
}

typedef struct {
	git_repository *repo;
	git_tag_foreach_cb cb;
	void *cb_data;
} tag_cb_data;

static int tags_cb(const char *ref, void *data)
{
	int error;
	git_oid oid;
	tag_cb_data *d = (tag_cb_data *)data;

	if (git__prefixcmp(ref, GIT_REFS_TAGS_DIR) != 0)
		return 0; /* no tag */

	if (!(error = git_reference_name_to_id(&oid, d->repo, ref))) {
		if ((error = d->cb(ref, &oid, d->cb_data)) != 0)
			giterr_set_after_callback_function(error, "git_tag_foreach");
	}

	return error;
}

int git_tag_foreach(git_repository *repo, git_tag_foreach_cb cb, void *cb_data)
{
	tag_cb_data data;

	assert(repo && cb);

	data.cb = cb;
	data.cb_data = cb_data;
	data.repo = repo;

	return git_reference_foreach_name(repo, &tags_cb, &data);
}

typedef struct {
	git_vector *taglist;
	const char *pattern;
} tag_filter_data;

#define GIT_REFS_TAGS_DIR_LEN strlen(GIT_REFS_TAGS_DIR)

static int tag_list_cb(const char *tag_name, git_oid *oid, void *data)
{
	tag_filter_data *filter = (tag_filter_data *)data;
	GIT_UNUSED(oid);

	if (!*filter->pattern ||
		p_fnmatch(filter->pattern, tag_name + GIT_REFS_TAGS_DIR_LEN, 0) == 0)
	{
		char *matched = git__strdup(tag_name + GIT_REFS_TAGS_DIR_LEN);
		GITERR_CHECK_ALLOC(matched);

		return git_vector_insert(filter->taglist, matched);
	}

	return 0;
}

int git_tag_list_match(git_strarray *tag_names, const char *pattern, git_repository *repo)
{
	int error;
	tag_filter_data filter;
	git_vector taglist;

	assert(tag_names && repo && pattern);

	if ((error = git_vector_init(&taglist, 8, NULL)) < 0)
		return error;

	filter.taglist = &taglist;
	filter.pattern = pattern;

	error = git_tag_foreach(repo, &tag_list_cb, (void *)&filter);

	if (error < 0)
		git_vector_free(&taglist);

	tag_names->strings =
		(char **)git_vector_detach(&tag_names->count, NULL, &taglist);

	return 0;
}

int git_tag_list(git_strarray *tag_names, git_repository *repo)
{
	return git_tag_list_match(tag_names, "", repo);
}

int git_tag_peel(git_object **tag_target, const git_tag *tag)
{
	return git_object_peel(tag_target, (const git_object *)tag, GIT_OBJ_ANY);
}