/*
 * Copyright (C) 2009-2012 the libgit2 contributors
 *
 * 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 "git2/object.h"
#include "git2/repository.h"
#include "git2/signature.h"

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

const git_oid *git_tag_id(git_tag *c)
{
	return git_object_id((git_object *)c);
}

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

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

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

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

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

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

int git_tag__parse_buffer(git_tag *tag, const char *buffer, size_t length)
{
	static const char *tag_types[] = {
		NULL, "commit\n", "tree\n", "blob\n", "tag\n"
	};

	unsigned int i;
	size_t text_len;
	char *search;
	int error;

	const char *buffer_end = buffer + length;

	if ((error = git_oid__parse(&tag->target, &buffer, buffer_end, "object ")) < 0)
		return git__rethrow(error, "Failed to parse tag. Object field invalid");

	if (buffer + 5 >= buffer_end)
		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse tag. Object too short");

	if (memcmp(buffer, "type ", 5) != 0)
		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse tag. 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 git__throw(GIT_EOBJCORRUPTED, "Failed to parse tag. 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 git__throw(GIT_EOBJCORRUPTED, "Failed to parse tag. Invalid object type");

	if (buffer + 4 >= buffer_end)
		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse tag. Object too short");

	if (memcmp(buffer, "tag ", 4) != 0)
		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse tag. Tag field not found");

	buffer += 4;

	search = memchr(buffer, '\n', buffer_end - buffer);
	if (search == NULL)
		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse tag. Object too short");

	text_len = search - buffer;

	tag->tag_name = git__malloc(text_len + 1);
	if (tag->tag_name == NULL)
		return GIT_ENOMEM;

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

	buffer = search + 1;

	tag->tagger = NULL;
	if (*buffer != '\n') {
		tag->tagger = git__malloc(sizeof(git_signature));
		if (tag->tagger == NULL)
			return GIT_ENOMEM;

		if ((error = git_signature__parse(tag->tagger, &buffer, buffer_end, "tagger ", '\n') != 0)) {
			return git__rethrow(error, "Failed to parse tag");
		}
	}

	if( *buffer != '\n' )
		return git__throw(GIT_EOBJCORRUPTED, "Failed to parse tag. No new line before message");

	text_len = buffer_end - ++buffer;

	tag->message = git__malloc(text_len + 1);
	if (tag->message == NULL)
		return GIT_ENOMEM;

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

	return GIT_SUCCESS;
}

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;

	error = git_buf_joinpath(ref_name_out, GIT_REFS_TAGS_DIR, tag_name);
	if (error < GIT_SUCCESS)
		return git__rethrow(error, "Failed to retrieve tag reference");

	error = git_reference_lookup(&tag_ref, repo, ref_name_out->ptr);
	if (error < GIT_SUCCESS)
		return git__rethrow(error, "Failed to retrieve tag reference");

	*tag_reference_out = tag_ref;

	return GIT_SUCCESS;
}

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)
{
	int error = GIT_SUCCESS;
	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');
	git_buf_puts(&tag, message);

	if (git_buf_oom(&tag)) {
		git_buf_free(&tag);
		return git__throw(GIT_ENOMEM, "Not enough memory to build the tag data");
	}

	error = git_repository_odb__weakptr(&odb, repo);
	if (error < GIT_SUCCESS) {
		git_buf_free(&tag);
		return error;
	}

	error = git_odb_write(oid, odb, tag.ptr, tag.size, GIT_OBJ_TAG);
	git_buf_free(&tag);

	if (error < GIT_SUCCESS)
		return git__rethrow(error, "Failed to create tag annotation");

	return error;
}

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, should_update_ref = 0;
	const char *errmsg = "Failed to create tag";

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

	if (git_object_owner(target) != repo)
		return git__throw(GIT_EINVALIDARGS,
			"The given target does not belong to this repository");

	error = retrieve_tag_reference(&new_ref, &ref_name, repo, tag_name);
	if (error < GIT_SUCCESS && error != GIT_ENOTFOUND)
		goto cleanup;

	/** Ensure the tag name doesn't conflict with an already existing
	 *	reference unless overwriting has explictly been requested **/
	if (new_ref != NULL) {
		if (!allow_ref_overwrite) {
			git_oid_cpy(oid, git_reference_oid(new_ref));
			error = GIT_EEXISTS;
			errmsg = "Tag already exists";
			goto cleanup;
		} else {
			should_update_ref = 1;
		}
	}

	if (create_tag_annotation) {
		if ((error = write_tag_annotation(oid, repo, tag_name, target, tagger, message)) < GIT_SUCCESS)
			goto cleanup;
	} else
		git_oid_cpy(oid, git_object_id(target));

	if (!should_update_ref)
		error = git_reference_create_oid(&new_ref, repo, ref_name.ptr, oid, 0);
	else
		error = git_reference_set_oid(new_ref, oid);

cleanup:
	git_reference_free(new_ref);
	git_buf_free(&ref_name);

	if (error < GIT_SUCCESS)
		git__rethrow(error, "%s", errmsg);

	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_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, should_update_ref = 0;
	const char *errmsg = "Failed to create tag";
	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));

	error = git_repository_odb__weakptr(&odb, repo);
	if (error < GIT_SUCCESS)
		return error;

	/* validate the buffer */
	if ((error = git_tag__parse_buffer(&tag, buffer, strlen(buffer))) < GIT_SUCCESS)
		goto cleanup;

	/* validate the target */
	if ((error = git_odb_read(&target_obj, odb, &tag.target)) < GIT_SUCCESS)
		goto cleanup;

	if (tag.type != target_obj->raw.type) {
		error = GIT_EINVALIDTYPE;
		errmsg = "The type for the given target is invalid";
		goto cleanup;
	}

	git_odb_object_free(target_obj);

	error = retrieve_tag_reference(&new_ref, &ref_name, repo, tag.tag_name);
	if (error < GIT_SUCCESS && error != GIT_ENOTFOUND)
		goto cleanup;

	/** Ensure the tag name doesn't conflict with an already existing
	 *	reference unless overwriting has explictly been requested **/
	if (new_ref != NULL) {
		if (!allow_ref_overwrite) {
			git_oid_cpy(oid, git_reference_oid(new_ref));
			error = GIT_EEXISTS;
			errmsg = "Tag already exists";
			goto cleanup;
		} else {
			should_update_ref = 1;
		}
	}

	/* write the buffer */
	if ((error = git_odb_open_wstream(&stream, odb, strlen(buffer), GIT_OBJ_TAG)) < GIT_SUCCESS)
		goto cleanup;

	stream->write(stream, buffer, strlen(buffer));

	error = stream->finalize_write(oid, stream);
	stream->free(stream);

	if (error < GIT_SUCCESS)
		goto cleanup;

	if (!should_update_ref)
		error = git_reference_create_oid(&new_ref, repo, ref_name.ptr, oid, 0);
	else
		error = git_reference_set_oid(new_ref, oid);

cleanup:
	git_reference_free(new_ref);
	git_signature_free(tag.tagger);
	git__free(tag.tag_name);
	git__free(tag.message);
	git_buf_free(&ref_name);

	if (error < GIT_SUCCESS)
		git__rethrow(error, "%s", errmsg);

	return error;
}

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

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

	git_buf_free(&ref_name);

	if (error < GIT_SUCCESS)
		return git__rethrow(error, "Failed to delete tag");

	return git_reference_delete(tag_ref);
}

int git_tag__parse(git_tag *tag, git_odb_object *obj)
{
	assert(tag);
	return git_tag__parse_buffer(tag, obj->raw.data, obj->raw.len);
}

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, void *payload)
{
	tag_filter_data *filter;

	if (git__prefixcmp(tag_name, GIT_REFS_TAGS_DIR) != 0)
		return GIT_SUCCESS;

	filter = (tag_filter_data *)payload;
	if (!*filter->pattern || p_fnmatch(filter->pattern, tag_name + GIT_REFS_TAGS_DIR_LEN, 0) == GIT_SUCCESS)
		return git_vector_insert(filter->taglist, git__strdup(tag_name));

	return GIT_SUCCESS;
}

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 (git_vector_init(&taglist, 8, NULL) < GIT_SUCCESS)
		return GIT_ENOMEM;

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

	error = git_reference_foreach(repo, GIT_REF_OID|GIT_REF_PACKED, &tag_list_cb, (void *)&filter);
	if (error < GIT_SUCCESS) {
		git_vector_free(&taglist);
		return git__rethrow(error, "Failed to list tags");
	}

	tag_names->strings = (char **)taglist.contents;
	tag_names->count = taglist.length;
	return GIT_SUCCESS;
}

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, git_tag *tag)
{
	int error;
	git_object *target;

	assert(tag_target && tag);

	if (git_tag_target(&target, tag) < 0)
		return -1;

	if (git_object_type(target) == GIT_OBJ_TAG) {
		error = git_tag_peel(tag_target, (git_tag *)target);
		git_object_free(target);
		return error;
	}

	*tag_target = target;
	return 0;
}
