#define WIN32_LEAN_AND_MEAN

#include <fx/core/stringstream.h>
#include <fx/io/path.h>
#include <fx/ds/string.h>
#include <Windows.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

struct fx_path {
	struct fx_dsref base;
	struct fx_string *pathstr;
};

static void path_release(struct fx_dsref *obj);
static void path_to_string(struct fx_dsref *obj, struct fx_stringstream *out);

static struct fx_dsref_type path_type = {
	.t_name = "corelib::path",
	.t_flags = FX_DSREF_FUNDAMENTAL,
	.t_id = FX_DSREF_TYPE_PATH,
	.t_instance_size = sizeof(struct fx_path),
	.t_release = path_release,
	.t_to_string = path_to_string,
};

struct fx_path *fx_path_create()
{
	struct fx_path *path
		= (struct fx_path *)fx_dsref_type_instantiate(&path_type);
	if (!path) {
		return NULL;
	}

	path->pathstr = fx_string_create();
	if (!path->pathstr) {
		fx_path_release(path);
		return NULL;
	}

	return path;
}

struct fx_path *fx_path_create_root()
{
	const char *system_drive = getenv("SystemDrive");
	if (!system_drive) {
		/* take an educated guess. */
		system_drive = "C:";
	}

	size_t system_drive_len = strlen(system_drive);

	struct fx_path *path = fx_path_create();
	if (!path) {
		return NULL;
	}

	fx_string_append_cstr(path->pathstr, system_drive);
	if (system_drive[system_drive_len - 1] != '\\') {
		fx_string_append_cstr(path->pathstr, "\\");
	}

	return path;
}

struct fx_path *fx_path_create_cwd()
{
	DWORD cwd_len = GetCurrentDirectory(0, NULL);
	if (cwd_len == 0) {
		return NULL;
	}

	TCHAR *cwd_buf = malloc(cwd_len + 1);
	if (!cwd_buf) {
		return NULL;
	}

	cwd_len = GetCurrentDirectory(cwd_len + 1, cwd_buf);
	if (cwd_len == 0) {
		free(cwd_buf);
		return NULL;
	}

	struct fx_path *path = fx_path_create();
	if (!path) {
		return NULL;
	}

	for (DWORD i = 0; i < cwd_len; i++) {
		TCHAR c = cwd_buf[i];
		char s[] = {(c >= 128 ? '?' : (char)c), 0};
		fx_string_append_cstr(path->pathstr, s);
	}

	free(cwd_buf);
	return path;
}

struct fx_path *fx_path_create_from_cstr(const char *cstr)
{
	struct fx_path *path = fx_path_create();
	if (!path) {
		return NULL;
	}

	char prev = 0;

	for (size_t i = 0; cstr[i]; i++) {
		char c = cstr[i];
		if (c == '\\') {
			c = '/';
		}

		if (prev == '/' && c == '/') {
			continue;
		}


		char s[] = {c, 0};
		fx_string_append_cstr(path->pathstr, s);
		prev = c;
	}

	while (fx_string_back(path->pathstr) == '/') {
		fx_string_pop_back(path->pathstr);
	}

	return path;
}

static void append_path(struct fx_path *dest, const struct fx_path *src)
{
	if (fx_path_is_absolute(src)) {
		fx_string_clear(dest->pathstr);
		fx_string_append_s(dest->pathstr, src->pathstr);
		return;
	}

	if (fx_string_back(dest->pathstr) != '/'
	    && fx_string_front(src->pathstr) != '/') {
		char s[] = {'/', 0};
		fx_string_append_cstr(dest->pathstr, s);
	}

	fx_string_append_s(dest->pathstr, src->pathstr);
}

struct fx_path *fx_path_join(
	const fx_path *paths[], size_t nr_paths)
{
	struct fx_path *result = fx_path_create();
	if (!result) {
		return NULL;
	}

	for (size_t i = 0; i < nr_paths; i++) {
		if (paths[i]) {
			append_path(result, paths[i]);
		}
	}

	return result;
}

struct fx_path *fx_path_make_absolute(const struct fx_path *in)
{
	return NULL;
}

struct fx_path *fx_path_make_relative(const struct fx_path *in)
{
	return NULL;
}

struct fx_path *fx_path_make_canonical(const struct fx_path *in)
{
	return NULL;
}

bool fx_path_is_absolute(const struct fx_path *path)
{
	const char *s = fx_string_ptr(path->pathstr);

	size_t i;
	for (i = 0; s[i]; i++) {
		char c = s[i];

		if (!isalpha(c)) {
			break;
		}
	}

	if (s[i++] != ':') {
		return false;
	}

	if (s[i++] != '/') {
		return false;
	}

	return true;
}

bool fx_path_exists(const struct fx_path *path)
{
	DWORD attrib = GetFileAttributesA(fx_path_ptr(path));
	return attrib != INVALID_FILE_ATTRIBUTES;
}

bool fx_path_is_file(const struct fx_path *path)
{
	DWORD attrib = GetFileAttributesA(fx_path_ptr(path));
	if (attrib == INVALID_FILE_ATTRIBUTES) {
		return false;
	}

	return (attrib & FILE_ATTRIBUTE_NORMAL) != 0;
}

bool fx_path_is_directory(const struct fx_path *path)
{
	DWORD attrib = GetFileAttributesA(fx_path_ptr(path));
	if (attrib == INVALID_FILE_ATTRIBUTES) {
		return false;
	}

	return (attrib & FILE_ATTRIBUTE_DIRECTORY) != 0;
}

const char *fx_path_ptr(const struct fx_path *path)
{
	return fx_string_ptr(path->pathstr);
}

void path_release(struct fx_dsref* obj)
{
	struct fx_path *path = FX_PATH(obj);
	fx_string_release(path->pathstr);
}

void path_to_string(struct fx_dsref* obj, struct fx_stringstream* out)
{
	struct fx_path *path = (struct fx_path *)obj;

	fx_stringstream_add(out, fx_string_ptr(path->pathstr));
}