/*

 * 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 "git2/common.h"

#include "git2/object.h"

#include "git2/repository.h"

#include "git2/signature.h"

#include "git2/sys/commit.h"

#include "common.h"

#include "odb.h"

#include "commit.h"

#include "signature.h"

#include "message.h"

#include "refs.h"

#include "object.h"

#include "oidarray.h"

void git_commit__free(void *_commit)

{

	git_commit *commit = _commit;

	git_array_clear(commit->parent_ids);

	git_signature_free(commit->author);

	git_signature_free(commit->committer);

	git__free(commit->raw_header);

	git__free(commit->raw_message);

	git__free(commit->message_encoding);

	git__free(commit->summary);

	git__free(commit->body);

	git__free(commit);

}

static int git_commit__create_buffer_internal(

	git_buf *out,

	const git_signature *author,

	const git_signature *committer,

	const char *message_encoding,

	const char *message,

	const git_oid *tree,

	git_array_oid_t *parents)

{

	size_t i = 0;

	const git_oid *parent;

	assert(out && tree);

	git_oid__writebuf(out, "tree ", tree);

	for (i = 0; i < git_array_size(*parents); i++) {

		parent = git_array_get(*parents, i);

		git_oid__writebuf(out, "parent ", parent);

	}

	git_signature__writebuf(out, "author ", author);

	git_signature__writebuf(out, "committer ", committer);

	if (message_encoding != NULL)

		git_buf_printf(out, "encoding %s\n", message_encoding);

	git_buf_putc(out, '\n');

	if (git_buf_puts(out, message) < 0)

		goto on_error;

	return 0;

on_error:

	git_buf_free(out);

	return -1;

}

static int validate_tree_and_parents(git_array_oid_t *parents, git_repository *repo, const git_oid *tree,

				     git_commit_parent_callback parent_cb, void *parent_payload,

				     const git_oid *current_id, bool validate)

{

	size_t i;

	int error;

	git_oid *parent_cpy;

	const git_oid *parent;

	if (validate && !git_object__is_valid(repo, tree, GIT_OBJ_TREE))

		return -1;

	i = 0;

	while ((parent = parent_cb(i, parent_payload)) != NULL) {

		if (validate && !git_object__is_valid(repo, parent, GIT_OBJ_COMMIT)) {

			error = -1;

			goto on_error;

		}

		parent_cpy = git_array_alloc(*parents);

		GITERR_CHECK_ALLOC(parent_cpy);

		git_oid_cpy(parent_cpy, parent);

		i++;

	}

	if (current_id && (parents->size == 0 || git_oid_cmp(current_id, git_array_get(*parents, 0)))) {

		giterr_set(GITERR_OBJECT, "failed to create commit: current tip is not the first parent");

		error = GIT_EMODIFIED;

		goto on_error;

	}

	return 0;

on_error:

	git_array_clear(*parents);

	return error;

}

static int git_commit__create_internal(

	git_oid *id,

	git_repository *repo,

	const char *update_ref,

	const git_signature *author,

	const git_signature *committer,

	const char *message_encoding,

	const char *message,

	const git_oid *tree,

	git_commit_parent_callback parent_cb,

	void *parent_payload,

	bool validate)

{

	int error;

	git_odb *odb;

	git_reference *ref = NULL;

	git_buf buf = GIT_BUF_INIT;

	const git_oid *current_id = NULL;

	git_array_oid_t parents = GIT_ARRAY_INIT;

	if (update_ref) {

		error = git_reference_lookup_resolved(&ref, repo, update_ref, 10);

		if (error < 0 && error != GIT_ENOTFOUND)

			return error;

	}

	giterr_clear();

	if (ref)

		current_id = git_reference_target(ref);

	if ((error = validate_tree_and_parents(&parents, repo, tree, parent_cb, parent_payload, current_id, validate)) < 0)

		goto cleanup;

	error = git_commit__create_buffer_internal(&buf, author, committer,

						   message_encoding, message, tree,

						   &parents);

	if (error < 0)

		goto cleanup;

	if (git_repository_odb__weakptr(&odb, repo) < 0)

		goto cleanup;

	if (git_odb__freshen(odb, tree) < 0)

		goto cleanup;

	if (git_odb_write(id, odb, buf.ptr, buf.size, GIT_OBJ_COMMIT) < 0)

		goto cleanup;

	if (update_ref != NULL) {

		error = git_reference__update_for_commit(

			repo, ref, update_ref, id, "commit");

		goto cleanup;

	}

cleanup:

	git_array_clear(parents);

	git_reference_free(ref);

	git_buf_free(&buf;;

	return error;

}

int git_commit_create_from_callback(

	git_oid *id,

	git_repository *repo,

	const char *update_ref,

	const git_signature *author,

	const git_signature *committer,

	const char *message_encoding,

	const char *message,

	const git_oid *tree,

	git_commit_parent_callback parent_cb,

	void *parent_payload)

{

	return git_commit__create_internal(

		id, repo, update_ref, author, committer, message_encoding, message,

		tree, parent_cb, parent_payload, true);

}

typedef struct {

	size_t total;

	va_list args;

} commit_parent_varargs;

static const git_oid *commit_parent_from_varargs(size_t curr, void *payload)

{

	commit_parent_varargs *data = payload;

	const git_commit *commit;

	if (curr >= data->total)

		return NULL;

	commit = va_arg(data->args, const git_commit *);

	return commit ? git_commit_id(commit) : NULL;

}

int git_commit_create_v(

	git_oid *id,

	git_repository *repo,

	const char *update_ref,

	const git_signature *author,

	const git_signature *committer,

	const char *message_encoding,

	const char *message,

	const git_tree *tree,

	size_t parent_count,

	...)

{

	int error = 0;

	commit_parent_varargs data;

	assert(tree && git_tree_owner(tree) == repo);

	data.total = parent_count;

	va_start(data.args, parent_count);

	error = git_commit__create_internal(

		id, repo, update_ref, author, committer,

		message_encoding, message, git_tree_id(tree),

		commit_parent_from_varargs, &data, false);

	va_end(data.args);

	return error;

}

typedef struct {

	size_t total;

	const git_oid **parents;

} commit_parent_oids;

static const git_oid *commit_parent_from_ids(size_t curr, void *payload)

{

	commit_parent_oids *data = payload;

	return (curr < data->total) ? data->parents[curr] : NULL;

}

int git_commit_create_from_ids(

	git_oid *id,

	git_repository *repo,

	const char *update_ref,

	const git_signature *author,

	const git_signature *committer,

	const char *message_encoding,

	const char *message,

	const git_oid *tree,

	size_t parent_count,

	const git_oid *parents[])

{

	commit_parent_oids data = { parent_count, parents };

	return git_commit__create_internal(

		id, repo, update_ref, author, committer,

		message_encoding, message, tree,

		commit_parent_from_ids, &data, true);

}

typedef struct {

	size_t total;

	const git_commit **parents;

	git_repository *repo;

} commit_parent_data;

static const git_oid *commit_parent_from_array(size_t curr, void *payload)

{

	commit_parent_data *data = payload;

	const git_commit *commit;

	if (curr >= data->total)

		return NULL;

	commit = data->parents[curr];

	if (git_commit_owner(commit) != data->repo)

		return NULL;

	return git_commit_id(commit);

}

int git_commit_create(

	git_oid *id,

	git_repository *repo,

	const char *update_ref,

	const git_signature *author,

	const git_signature *committer,

	const char *message_encoding,

	const char *message,

	const git_tree *tree,

	size_t parent_count,

	const git_commit *parents[])

{

	commit_parent_data data = { parent_count, parents, repo };

	assert(tree && git_tree_owner(tree) == repo);

	return git_commit__create_internal(

		id, repo, update_ref, author, committer,

		message_encoding, message, git_tree_id(tree),

		commit_parent_from_array, &data, false);

}

static const git_oid *commit_parent_for_amend(size_t curr, void *payload)

{

	const git_commit *commit_to_amend = payload;

	if (curr >= git_array_size(commit_to_amend->parent_ids))

		return NULL;

	return git_array_get(commit_to_amend->parent_ids, curr);

}

int git_commit_amend(

	git_oid *id,

	const git_commit *commit_to_amend,

	const char *update_ref,

	const git_signature *author,

	const git_signature *committer,

	const char *message_encoding,

	const char *message,

	const git_tree *tree)

{

	git_repository *repo;

	git_oid tree_id;

	git_reference *ref;

	int error;

	assert(id && commit_to_amend);

	repo = git_commit_owner(commit_to_amend);

	if (!author)

		author = git_commit_author(commit_to_amend);

	if (!committer)

		committer = git_commit_committer(commit_to_amend);

	if (!message_encoding)

		message_encoding = git_commit_message_encoding(commit_to_amend);

	if (!message)

		message = git_commit_message(commit_to_amend);

	if (!tree) {

		git_tree *old_tree;

		GITERR_CHECK_ERROR( git_commit_tree(&old_tree, commit_to_amend) );

		git_oid_cpy(&tree_id, git_tree_id(old_tree));

		git_tree_free(old_tree);

	} else {

		assert(git_tree_owner(tree) == repo);

		git_oid_cpy(&tree_id, git_tree_id(tree));

	}

	if (update_ref) {

		if ((error = git_reference_lookup_resolved(&ref, repo, update_ref, 5)) < 0)

			return error;

		if (git_oid_cmp(git_commit_id(commit_to_amend), git_reference_target(ref))) {

			git_reference_free(ref);

			giterr_set(GITERR_REFERENCE, "commit to amend is not the tip of the given branch");

			return -1;

		}

	}

	error = git_commit__create_internal(

		id, repo, NULL, author, committer, message_encoding, message,

		&tree_id, commit_parent_for_amend, (void *)commit_to_amend, false);

	if (!error && update_ref) {

		error = git_reference__update_for_commit(

			repo, ref, NULL, id, "commit");

		git_reference_free(ref);

	}

	return error;

}

int git_commit__parse(void *_commit, git_odb_object *odb_obj)

{

	git_commit *commit = _commit;

	const char *buffer_start = git_odb_object_data(odb_obj), *buffer;

	const char *buffer_end = buffer_start + git_odb_object_size(odb_obj);

	git_oid parent_id;

	size_t header_len;

	git_signature dummy_sig;

	buffer = buffer_start;

	/* Allocate for one, which will allow not to realloc 90% of the time  */

	git_array_init_to_size(commit->parent_ids, 1);

	GITERR_CHECK_ARRAY(commit->parent_ids);

	/* The tree is always the first field */

	if (git_oid__parse(&commit->tree_id, &buffer, buffer_end, "tree ") < 0)

		goto bad_buffer;

	/*

	 * TODO: commit grafts!

	 */

	while (git_oid__parse(&parent_id, &buffer, buffer_end, "parent ") == 0) {

		git_oid *new_id = git_array_alloc(commit->parent_ids);

		GITERR_CHECK_ALLOC(new_id);

		git_oid_cpy(new_id, &parent_id);

	}

	commit->author = git__malloc(sizeof(git_signature));

	GITERR_CHECK_ALLOC(commit->author);

	if (git_signature__parse(commit->author, &buffer, buffer_end, "author ", '\n') < 0)

		return -1;

	/* Some tools create multiple author fields, ignore the extra ones */

	while ((size_t)(buffer_end - buffer) >= strlen("author ") && !git__prefixcmp(buffer, "author ")) {

		if (git_signature__parse(&dummy_sig, &buffer, buffer_end, "author ", '\n') < 0)

			return -1;

		git__free(dummy_sig.name);

		git__free(dummy_sig.email);

	}

	/* Always parse the committer; we need the commit time */

	commit->committer = git__malloc(sizeof(git_signature));

	GITERR_CHECK_ALLOC(commit->committer);

	if (git_signature__parse(commit->committer, &buffer, buffer_end, "committer ", '\n') < 0)

		return -1;

	/* Parse add'l header entries */

	while (buffer < buffer_end) {

		const char *eoln = buffer;

		if (buffer[-1] == '\n' && buffer[0] == '\n')

			break;

		while (eoln < buffer_end && *eoln != '\n')

			++eoln;

		if (git__prefixncmp(buffer, buffer_end - buffer, "encoding ") == 0) {

			buffer += strlen("encoding ");

			commit->message_encoding = git__strndup(buffer, eoln - buffer);

			GITERR_CHECK_ALLOC(commit->message_encoding);

		}

		if (eoln < buffer_end && *eoln == '\n')

			++eoln;

		buffer = eoln;

	}

	header_len = buffer - buffer_start;

	commit->raw_header = git__strndup(buffer_start, header_len);

	GITERR_CHECK_ALLOC(commit->raw_header);

	/* point "buffer" to data after header, +1 for the final LF */

	buffer = buffer_start + header_len + 1;

	/* extract commit message */

	if (buffer <= buffer_end)

		commit->raw_message = git__strndup(buffer, buffer_end - buffer);

	else

		commit->raw_message = git__strdup("");

	GITERR_CHECK_ALLOC(commit->raw_message);

	return 0;

bad_buffer:

	giterr_set(GITERR_OBJECT, "failed to parse bad commit object");

	return -1;

}

#define GIT_COMMIT_GETTER(_rvalue, _name, _return) \

	_rvalue git_commit_##_name(const git_commit *commit) \

	{\

		assert(commit); \

		return _return; \

	}

GIT_COMMIT_GETTER(const git_signature *, author, commit->author)

GIT_COMMIT_GETTER(const git_signature *, committer, commit->committer)

GIT_COMMIT_GETTER(const char *, message_raw, commit->raw_message)

GIT_COMMIT_GETTER(const char *, message_encoding, commit->message_encoding)

GIT_COMMIT_GETTER(const char *, raw_header, commit->raw_header)

GIT_COMMIT_GETTER(git_time_t, time, commit->committer->when.time)

GIT_COMMIT_GETTER(int, time_offset, commit->committer->when.offset)

GIT_COMMIT_GETTER(unsigned int, parentcount, (unsigned int)git_array_size(commit->parent_ids))

GIT_COMMIT_GETTER(const git_oid *, tree_id, &commit->tree_id)

const char *git_commit_message(const git_commit *commit)

{

	const char *message;

	assert(commit);

	message = commit->raw_message;

	/* trim leading newlines from raw message */

	while (*message && *message == '\n')

		++message;

	return message;

}

const char *git_commit_summary(git_commit *commit)

{

	git_buf summary = GIT_BUF_INIT;

	const char *msg, *space;

	bool space_contains_newline = false;

	assert(commit);

	if (!commit->summary) {

		for (msg = git_commit_message(commit), space = NULL; *msg; ++msg) {

			char next_character = msg[0];

			/* stop processing at the end of the first paragraph */

			if (next_character == '\n' && (!msg[1] || msg[1] == '\n'))

				break;

			/* record the beginning of contiguous whitespace runs */

			else if (git__isspace(next_character)) {

				if(space == NULL) {

					space = msg;

					space_contains_newline = false;

				}

				space_contains_newline |= next_character == '\n';

			}

			/* the next character is non-space */

			else {

				/* process any recorded whitespace */

				if (space) {

					if(space_contains_newline)

						git_buf_putc(&summary, ' '); /* if the space contains a newline, collapse to ' ' */

					else

						git_buf_put(&summary, space, (msg - space)); /* otherwise copy it */

					space = NULL;

				}

				/* copy the next character */

				git_buf_putc(&summary, next_character);

			}

		}

		commit->summary = git_buf_detach(&summary);

		if (!commit->summary)

			commit->summary = git__strdup("");

	}

	return commit->summary;

}

const char *git_commit_body(git_commit *commit)

{

	const char *msg, *end;

	assert(commit);

	if (!commit->body) {

		/* search for end of summary */

		for (msg = git_commit_message(commit); *msg; ++msg)

			if (msg[0] == '\n' && (!msg[1] || msg[1] == '\n'))

				break;

		/* trim leading and trailing whitespace */

		for (; *msg; ++msg)

			if (!git__isspace(*msg))

				break;

		for (end = msg + strlen(msg) - 1; msg <= end; --end)

			if (!git__isspace(*end))

				break;

		if (*msg)

			    commit->body = git__strndup(msg, end - msg + 1);

	}

	return commit->body;

}

int git_commit_tree(git_tree **tree_out, const git_commit *commit)

{

	assert(commit);

	return git_tree_lookup(tree_out, commit->object.repo, &commit->tree_id);

}

const git_oid *git_commit_parent_id(

	const git_commit *commit, unsigned int n)

{

	assert(commit);

	return git_array_get(commit->parent_ids, n);

}

int git_commit_parent(

	git_commit **parent, const git_commit *commit, unsigned int n)

{

	const git_oid *parent_id;

	assert(commit);

	parent_id = git_commit_parent_id(commit, n);

	if (parent_id == NULL) {

		giterr_set(GITERR_INVALID, "parent %u does not exist", n);

		return GIT_ENOTFOUND;

	}

	return git_commit_lookup(parent, commit->object.repo, parent_id);

}

int git_commit_nth_gen_ancestor(

	git_commit **ancestor,

	const git_commit *commit,

	unsigned int n)

{

	git_commit *current, *parent = NULL;

	int error;

	assert(ancestor && commit);

	if (git_commit_dup(&current, (git_commit *)commit) < 0)

		return -1;

	if (n == 0) {

		*ancestor = current;

		return 0;

	}

	while (n--) {

		error = git_commit_parent(&parent, current, 0);

		git_commit_free(current);

		if (error < 0)

			return error;

		current = parent;

	}

	*ancestor = parent;

	return 0;

}

int git_commit_header_field(git_buf *out, const git_commit *commit, const char *field)

{

	const char *eol, *buf = commit->raw_header;

	git_buf_clear(out);

	while ((eol = strchr(buf, '\n'))) {

		/* We can skip continuations here */

		if (buf[0] == ' ') {

			buf = eol + 1;

			continue;

		}

		/* Skip until we find the field we're after */

		if (git__prefixcmp(buf, field)) {

			buf = eol + 1;

			continue;

		}

		buf += strlen(field);

		/* Check that we're not matching a prefix but the field itself */

		if (buf[0] != ' ') {

			buf = eol + 1;

			continue;

		}

		buf++; /* skip the SP */

		git_buf_put(out, buf, eol - buf);

		if (git_buf_oom(out))

			goto oom;

		/* If the next line starts with SP, it's multi-line, we must continue */

		while (eol[1] == ' ') {

			git_buf_putc(out, '\n');

			buf = eol + 2;

			eol = strchr(buf, '\n');

			if (!eol)

				goto malformed;

			git_buf_put(out, buf, eol - buf);

		}

		if (git_buf_oom(out))

			goto oom;

		return 0;

	}

	giterr_set(GITERR_OBJECT, "no such field '%s'", field);

	return GIT_ENOTFOUND;

malformed:

	giterr_set(GITERR_OBJECT, "malformed header");

	return -1;

oom:

	giterr_set_oom();

	return -1;

}

int git_commit_extract_signature(git_buf *signature, git_buf *signed_data, git_repository *repo, git_oid *commit_id, const char *field)

{

	git_odb_object *obj;

	git_odb *odb;

	const char *buf;

	const char *h, *eol;

	int error;

	git_buf_clear(signature);

	git_buf_clear(signed_data);

	if (!field)

		field = "gpgsig";

	if ((error = git_repository_odb__weakptr(&odb, repo)) < 0)

		return error;

	if ((error = git_odb_read(&obj, odb, commit_id)) < 0)

		return error;

	if (obj->cached.type != GIT_OBJ_COMMIT) {

		giterr_set(GITERR_INVALID, "the requested type does not match the type in ODB");

		error = GIT_ENOTFOUND;

		goto cleanup;

	}

	buf = git_odb_object_data(obj);

	while ((h = strchr(buf, '\n')) && h[1] != '\0') {

		h++;

		if (git__prefixcmp(buf, field)) {

			if (git_buf_put(signed_data, buf, h - buf) < 0)

				return -1;

			buf = h;

			continue;

		}

		h = buf;

		h += strlen(field);

		eol = strchr(h, '\n');

		if (h[0] != ' ') {

			buf = h;

			continue;

		}

		if (!eol)

			goto malformed;

		h++; /* skip the SP */

		git_buf_put(signature, h, eol - h);

		if (git_buf_oom(signature))

			goto oom;

		/* If the next line starts with SP, it's multi-line, we must continue */

		while (eol[1] == ' ') {

			git_buf_putc(signature, '\n');

			h = eol + 2;

			eol = strchr(h, '\n');

			if (!eol)

				goto malformed;

			git_buf_put(signature, h, eol - h);

		}

		if (git_buf_oom(signature))

			goto oom;

		error = git_buf_puts(signed_data, eol+1);

		git_odb_object_free(obj);

		return error;

	}

	giterr_set(GITERR_OBJECT, "this commit is not signed");

	error = GIT_ENOTFOUND;

	goto cleanup;

malformed:

	giterr_set(GITERR_OBJECT, "malformed header");

	error = -1;

	goto cleanup;

oom:

	giterr_set_oom();

	error = -1;

	goto cleanup;

cleanup:

	git_odb_object_free(obj);

	git_buf_clear(signature);

	git_buf_clear(signed_data);

	return error;

}

int git_commit_create_buffer(git_buf *out,

	git_repository *repo,

	const git_signature *author,

	const git_signature *committer,

	const char *message_encoding,

	const char *message,

	const git_tree *tree,

	size_t parent_count,

	const git_commit *parents[])

{

	int error;

	commit_parent_data data = { parent_count, parents, repo };

	git_array_oid_t parents_arr = GIT_ARRAY_INIT;

	const git_oid *tree_id;

	assert(tree && git_tree_owner(tree) == repo);

	tree_id = git_tree_id(tree);

	if ((error = validate_tree_and_parents(&parents_arr, repo, tree_id, commit_parent_from_array, &data, NULL, true)) < 0)

		return error;

	error = git_commit__create_buffer_internal(

		out, author, committer,

		message_encoding, message, tree_id,

		&parents_arr);

	git_array_clear(parents_arr);

	return error;

}

/**

 * Append to 'out' properly marking continuations when there's a newline in 'content'

 */

static void format_header_field(git_buf *out, const char *field, const char *content)

{

	const char *lf;

	assert(out && field && content);

	git_buf_puts(out, field);

	git_buf_putc(out, ' ');

	while ((lf = strchr(content, '\n')) != NULL) {

		git_buf_put(out, content, lf - content);

		git_buf_puts(out, "\n ");

		content = lf + 1;

	}

	git_buf_puts(out, content);

	git_buf_putc(out, '\n');

}

int git_commit_create_with_signature(

	git_oid *out,

	git_repository *repo,

	const char *commit_content,

	const char *signature,

	const char *signature_field)

{

	git_odb *odb;

	int error = 0;

	const char *field;

	const char *header_end;

	git_buf commit = GIT_BUF_INIT;

	/* We start by identifying the end of the commit header */

	header_end = strstr(commit_content, "\n\n");

	if (!header_end) {

		giterr_set(GITERR_INVALID, "malformed commit contents");

		return -1;

	}

	field = signature_field ? signature_field : "gpgsig";

	/* The header ends after the first LF */

	header_end++;

	git_buf_put(&commit, commit_content, header_end - commit_content);

	format_header_field(&commit, field, signature);

	git_buf_puts(&commit, header_end);

	if (git_buf_oom(&commit))

		return -1;