#include "clar_libgit2.h"
#include "fileops.h"
#include "refs.h"
#include "tree.h"
#include "merge_helpers.h"
#include "merge.h"
#include "git2/merge.h"
#include "git2/sys/index.h"

int merge_trees_from_branches(
	git_index **index, git_repository *repo,
	const char *ours_name, const char *theirs_name,
	git_merge_options *opts)
{
	git_commit *our_commit, *their_commit, *ancestor_commit = NULL;
	git_tree *our_tree, *their_tree, *ancestor_tree = NULL;
	git_oid our_oid, their_oid, ancestor_oid;
	git_buf branch_buf = GIT_BUF_INIT;
	int error;

	git_buf_printf(&branch_buf, "%s%s", GIT_REFS_HEADS_DIR, ours_name);
	cl_git_pass(git_reference_name_to_id(&our_oid, repo, branch_buf.ptr));
	cl_git_pass(git_commit_lookup(&our_commit, repo, &our_oid));

	git_buf_clear(&branch_buf);
	git_buf_printf(&branch_buf, "%s%s", GIT_REFS_HEADS_DIR, theirs_name);
	cl_git_pass(git_reference_name_to_id(&their_oid, repo, branch_buf.ptr));
	cl_git_pass(git_commit_lookup(&their_commit, repo, &their_oid));

	error = git_merge_base(&ancestor_oid, repo, git_commit_id(our_commit), git_commit_id(their_commit));

	if (error != GIT_ENOTFOUND) {
		cl_git_pass(error);

		cl_git_pass(git_commit_lookup(&ancestor_commit, repo, &ancestor_oid));
		cl_git_pass(git_commit_tree(&ancestor_tree, ancestor_commit));
	}

	cl_git_pass(git_commit_tree(&our_tree, our_commit));
	cl_git_pass(git_commit_tree(&their_tree, their_commit));

	cl_git_pass(git_merge_trees(index, repo, ancestor_tree, our_tree, their_tree, opts));

	git_buf_free(&branch_buf);
	git_tree_free(our_tree);
	git_tree_free(their_tree);
	git_tree_free(ancestor_tree);
	git_commit_free(our_commit);
	git_commit_free(their_commit);
	git_commit_free(ancestor_commit);

	return 0;
}

int merge_commits_from_branches(
	git_index **index, git_repository *repo,
	const char *ours_name, const char *theirs_name,
	git_merge_options *opts)
{
	git_commit *our_commit, *their_commit;
	git_oid our_oid, their_oid;
	git_buf branch_buf = GIT_BUF_INIT;

	git_buf_printf(&branch_buf, "%s%s", GIT_REFS_HEADS_DIR, ours_name);
	cl_git_pass(git_reference_name_to_id(&our_oid, repo, branch_buf.ptr));
	cl_git_pass(git_commit_lookup(&our_commit, repo, &our_oid));

	git_buf_clear(&branch_buf);
	git_buf_printf(&branch_buf, "%s%s", GIT_REFS_HEADS_DIR, theirs_name);
	cl_git_pass(git_reference_name_to_id(&their_oid, repo, branch_buf.ptr));
	cl_git_pass(git_commit_lookup(&their_commit, repo, &their_oid));

	cl_git_pass(git_merge_commits(index, repo, our_commit, their_commit, opts));

	git_buf_free(&branch_buf);
	git_commit_free(our_commit);
	git_commit_free(their_commit);

	return 0;
}

int merge_branches(git_repository *repo,
	const char *ours_branch, const char *theirs_branch,
	git_merge_options *merge_opts, git_checkout_options *checkout_opts)
{
	git_reference *head_ref, *theirs_ref;
	git_merge_head *theirs_head;
	git_checkout_options head_checkout_opts = GIT_CHECKOUT_OPTIONS_INIT;

	head_checkout_opts.checkout_strategy = GIT_CHECKOUT_FORCE;

	cl_git_pass(git_reference_symbolic_create(&head_ref, repo, "HEAD", ours_branch, 1, NULL, NULL));
	cl_git_pass(git_checkout_head(repo, &head_checkout_opts));

	cl_git_pass(git_reference_lookup(&theirs_ref, repo, theirs_branch));
	cl_git_pass(git_merge_head_from_ref(&theirs_head, repo, theirs_ref));

	cl_git_pass(git_merge(repo, (const git_merge_head **)&theirs_head, 1, merge_opts, checkout_opts));

	git_reference_free(head_ref);
	git_reference_free(theirs_ref);
	git_merge_head_free(theirs_head);

	return 0;
}

void merge__dump_index_entries(git_vector *index_entries)
{
	size_t i;
	const git_index_entry *index_entry;

	printf ("\nINDEX [%d]:\n", (int)index_entries->length);
	for (i = 0; i < index_entries->length; i++) {
		index_entry = index_entries->contents[i];

		printf("%o ", index_entry->mode);
		printf("%s ", git_oid_allocfmt(&index_entry->id));
		printf("%d ", git_index_entry_stage(index_entry));
		printf("%s ", index_entry->path);
		printf("\n");
	}
	printf("\n");
}

void merge__dump_names(git_index *index)
{
	size_t i;
	const git_index_name_entry *conflict_name;

	for (i = 0; i < git_index_name_entrycount(index); i++) {
		conflict_name = git_index_name_get_byindex(index, i);

		printf("%s %s %s\n", conflict_name->ancestor, conflict_name->ours, conflict_name->theirs);
	}
	printf("\n");
}

void merge__dump_reuc(git_index *index)
{
	size_t i;
	const git_index_reuc_entry *reuc;

	printf ("\nREUC:\n");
	for (i = 0; i < git_index_reuc_entrycount(index); i++) {
		reuc = git_index_reuc_get_byindex(index, i);

		printf("%s ", reuc->path);
		printf("%o ", reuc->mode[0]);
		printf("%s\n", git_oid_allocfmt(&reuc->oid[0]));
		printf("          %o ", reuc->mode[1]);
		printf("          %s\n", git_oid_allocfmt(&reuc->oid[1]));
		printf("          %o ", reuc->mode[2]);
		printf("          %s ", git_oid_allocfmt(&reuc->oid[2]));
		printf("\n");
	}
	printf("\n");
}

static int index_entry_eq_merge_index_entry(const struct merge_index_entry *expected, const git_index_entry *actual)
{
	git_oid expected_oid;
	bool test_oid;

	if (strlen(expected->oid_str) != 0) {
		cl_git_pass(git_oid_fromstr(&expected_oid, expected->oid_str));
		test_oid = 1;
	} else
		test_oid = 0;

	if (actual->mode != expected->mode ||
		(test_oid && git_oid_cmp(&actual->id, &expected_oid) != 0) ||
		git_index_entry_stage(actual) != expected->stage)
		return 0;

	if (actual->mode == 0 && (actual->path != NULL || strlen(expected->path) > 0))
		return 0;

	if (actual->mode != 0 && (strcmp(actual->path, expected->path) != 0))
		return 0;

	return 1;
}

static int name_entry_eq(const char *expected, const char *actual)
{
	if (strlen(expected) == 0)
		return (actual == NULL) ? 1 : 0;

	return (strcmp(expected, actual) == 0) ? 1 : 0;
}

static int name_entry_eq_merge_name_entry(const struct merge_name_entry *expected, const git_index_name_entry *actual)
{
	if (name_entry_eq(expected->ancestor_path, actual->ancestor) == 0 ||
		name_entry_eq(expected->our_path, actual->ours) == 0 ||
		name_entry_eq(expected->their_path, actual->theirs) == 0)
		return 0;

	return 1;
}

static int index_conflict_data_eq_merge_diff(const struct merge_index_conflict_data *expected, git_merge_diff *actual)
{
	if (!index_entry_eq_merge_index_entry(&expected->ancestor.entry, &actual->ancestor_entry) ||
		!index_entry_eq_merge_index_entry(&expected->ours.entry, &actual->our_entry) ||
		!index_entry_eq_merge_index_entry(&expected->theirs.entry, &actual->their_entry))
		return 0;

	if (expected->ours.status != actual->our_status ||
		expected->theirs.status != actual->their_status)
		return 0;

	return 1;
}

int merge_test_merge_conflicts(git_vector *conflicts, const struct merge_index_conflict_data expected[], size_t expected_len)
{
	git_merge_diff *actual;
	size_t i;

	if (conflicts->length != expected_len)
		return 0;

	for (i = 0; i < expected_len; i++) {
		actual = conflicts->contents[i];

		if (!index_conflict_data_eq_merge_diff(&expected[i], actual))
			return 0;
	}

	return 1;
}

int merge_test_index(git_index *index, const struct merge_index_entry expected[], size_t expected_len)
{
	size_t i;
	const git_index_entry *index_entry;

	/*
	dump_index_entries(&index->entries);
	*/

	if (git_index_entrycount(index) != expected_len)
		return 0;

	for (i = 0; i < expected_len; i++) {
		if ((index_entry = git_index_get_byindex(index, i)) == NULL)
			return 0;

		if (!index_entry_eq_merge_index_entry(&expected[i], index_entry))
			return 0;
	}

	return 1;
}

int merge_test_names(git_index *index, const struct merge_name_entry expected[], size_t expected_len)
{
	size_t i;
	const git_index_name_entry *name_entry;

	/*
	dump_names(index);
	*/

	if (git_index_name_entrycount(index) != expected_len)
		return 0;

	for (i = 0; i < expected_len; i++) {
		if ((name_entry = git_index_name_get_byindex(index, i)) == NULL)
			return 0;

		if (! name_entry_eq_merge_name_entry(&expected[i], name_entry))
			return 0;
	}

	return 1;
}

int merge_test_reuc(git_index *index, const struct merge_reuc_entry expected[], size_t expected_len)
{
	size_t i;
	const git_index_reuc_entry *reuc_entry;
	git_oid expected_oid;

	/*
	dump_reuc(index);
	*/

	if (git_index_reuc_entrycount(index) != expected_len)
		return 0;

	for (i = 0; i < expected_len; i++) {
		if ((reuc_entry = git_index_reuc_get_byindex(index, i)) == NULL)
			return 0;

		if (strcmp(reuc_entry->path, expected[i].path) != 0 ||
			reuc_entry->mode[0] != expected[i].ancestor_mode ||
			reuc_entry->mode[1] != expected[i].our_mode ||
			reuc_entry->mode[2] != expected[i].their_mode)
			return 0;

		if (expected[i].ancestor_mode > 0) {
			cl_git_pass(git_oid_fromstr(&expected_oid, expected[i].ancestor_oid_str));

			if (git_oid_cmp(&reuc_entry->oid[0], &expected_oid) != 0)
				return 0;
		}

		if (expected[i].our_mode > 0) {
			cl_git_pass(git_oid_fromstr(&expected_oid, expected[i].our_oid_str));

			if (git_oid_cmp(&reuc_entry->oid[1], &expected_oid) != 0)
				return 0;
		}

		if (expected[i].their_mode > 0) {
			cl_git_pass(git_oid_fromstr(&expected_oid, expected[i].their_oid_str));

			if (git_oid_cmp(&reuc_entry->oid[2], &expected_oid) != 0)
				return 0;
		}
	}

	return 1;
}

int dircount(void *payload, git_buf *pathbuf)
{
	size_t *entries = payload;
	size_t len = git_buf_len(pathbuf);

	if (len < 5 || strcmp(pathbuf->ptr + (git_buf_len(pathbuf) - 5), "/.git") != 0)
		(*entries)++;

	return 0;
}

int merge_test_workdir(git_repository *repo, const struct merge_index_entry expected[], size_t expected_len)
{
	size_t actual_len = 0, i;
	git_oid actual_oid, expected_oid;
	git_buf wd = GIT_BUF_INIT;

	git_buf_puts(&wd, repo->workdir);
	git_path_direach(&wd, 0, dircount, &actual_len);

	if (actual_len != expected_len)
		return 0;

	for (i = 0; i < expected_len; i++) {
		git_blob_create_fromworkdir(&actual_oid, repo, expected[i].path);
		git_oid_fromstr(&expected_oid, expected[i].oid_str);

		if (git_oid_cmp(&actual_oid, &expected_oid) != 0)
			return 0;
	}

	git_buf_free(&wd);

	return 1;
}
