/* 
 * ssheven
 * 
 * Copyright (c) 2020 by cy384 <cy384@cy384.com>
 * See LICENSE file for details
 */

#include "ssheven.h"
#include "ssheven-console.h"

// functions to convert error and status codes to strings
#include "ssheven-debug.c"

// error checking convenience macros
#define OT_CHECK(X) err = (X); if (err != noErr) { printf_i("" #X " failed\n"); return 0; };
#define SSH_CHECK(X) rc = (X); if (rc != LIBSSH2_ERROR_NONE) { printf_i("" #X " failed: %s\n", libssh2_error_string(rc)); return 0;};

// sinful globals
struct ssheven_console con = { NULL, {0}, 0, 0, 0, 0, 0, 0};
struct ssheven_ssh_connection ssh_con = { NULL, NULL, kOTInvalidEndpointRef, NULL, NULL };

enum { WAIT, READ, EXIT } read_thread_command = WAIT;
enum { UNITIALIZED, OPEN, CLEANUP, DONE } read_thread_state = UNITIALIZED;

char hostname[256] = {0};
char username[256] = {0};
char password[256] = {0};

// borrowed from Retro68 sample code
// draws the "default" indicator around a button
pascal void ButtonFrameProc(DialogRef dlg, DialogItemIndex itemNo)
{
	DialogItemType type;
	Handle itemH;
	Rect box;

	GetDialogItem(dlg, 1, &type, &itemH, &box);
	InsetRect(&box, -4, -4);
	PenSize(3, 3);
	FrameRoundRect(&box, 16, 16);
}

// event handler for a thread to yield when blocked
static pascal void yield_notifier(void* contextPtr, OTEventCode code, OTResult result, void* cookie)
{
	switch (code)
	{
		case kOTSyncIdleEvent:
			YieldToAnyThread();
			break;

		default:
			break;
	}
}

// read from the channel and print to console
void ssh_read(void)
{
	int rc = libssh2_channel_read(ssh_con.channel, ssh_con.recv_buffer, SSHEVEN_BUFFER_SIZE);

	if (rc == 0) return;

	if (rc > 0)
	{
		for(int i = 0; i < rc; ++i) print_char(ssh_con.recv_buffer[i]);
	}
	else
	{
		printf_i("channel read error: %s\n", libssh2_error_string(rc));
	}
}

int end_connection(void)
{
	read_thread_state = CLEANUP;

	OSStatus err = noErr;

	if (ssh_con.channel)
	{
		libssh2_channel_close(ssh_con.channel);
		libssh2_channel_free(ssh_con.channel);
		libssh2_session_disconnect(ssh_con.session, "Normal Shutdown, Thank you for playing");
		libssh2_session_free(ssh_con.session);
	}

	libssh2_exit();

	if (ssh_con.endpoint != kOTInvalidEndpointRef)
	{
		// request to close the TCP connection
		//OT_CHECK(OTSndOrderlyDisconnect(ssh_con.endpoint));
		OTSndOrderlyDisconnect(ssh_con.endpoint);

		// get and discard remaining data so we can finish closing the connection
		int rc = 1;
		OTFlags ot_flags;
		while (rc != kOTLookErr)
		{
			rc = OTRcv(ssh_con.endpoint, ssh_con.recv_buffer, 1, &ot_flags);
		}

		// finish closing the TCP connection
		OSStatus result = OTLook(ssh_con.endpoint);

		switch (result)
		{
			case T_DISCONNECT:
				OTRcvDisconnect(ssh_con.endpoint, nil);
				break;

			case T_ORDREL:
				err = OTRcvOrderlyDisconnect(ssh_con.endpoint);
				if (err == noErr)
				{
					err = OTSndOrderlyDisconnect(ssh_con.endpoint);
				}
				break;

			default:
				printf_i("unexpected OTLook result while closing: %s\n", OT_event_string(result));
				break;
		}

		// release endpoint
		err = OTUnbind(ssh_con.endpoint);
		if (err != noErr) printf_i("OTUnbind failed\n");

		err = OTCloseProvider(ssh_con.endpoint);
		if (err != noErr) printf_i("OTCloseProvider failed\n");
	}

	read_thread_state = DONE;
}

void check_network_events(void)
{
	OSStatus err = noErr;

	// check if we have any new network events
	OTResult look_result = OTLook(ssh_con.endpoint);

	switch (look_result)
	{
		case T_DATA:
		case T_EXDATA:
			// got data
			ssh_read();
			break;

		case T_RESET:
			// connection reset? close it/give up
			end_connection();
			break;

		case T_DISCONNECT:
			// got disconnected
			OTRcvDisconnect(ssh_con.endpoint, nil);
			end_connection();
			break;

		case T_ORDREL:
			// nice tcp disconnect requested by remote
			err = OTRcvOrderlyDisconnect(ssh_con.endpoint);
			if (err == noErr)
			{
				err = OTSndOrderlyDisconnect(ssh_con.endpoint);
			}
			end_connection();
			break;

		default:
			// something weird or irrelevant: ignore it
			break;
	}

	return;
}

void display_about_box(void)
{
	DialogRef about = GetNewDialog(DLOG_ABOUT, 0, (WindowPtr)-1);

	UpdateDialog(about, about->visRgn);

	while (!Button()) YieldToAnyThread();
	while (Button()) YieldToAnyThread();

	FlushEvents(everyEvent, 0);
	DisposeWindow(about);
}

void ssh_write(char* buf, int len)
{
	if (read_thread_state == OPEN && read_thread_command != EXIT)
	{
		int r = libssh2_channel_write(ssh_con.channel, buf, len);
		if (r < 1)
		{
			printf_i("failed to write to channel!\n");
			printf_i("closing connection!\n");
			read_thread_command = EXIT;
		}
	}
}

void ssh_paste(void)
{
	// GetScrap requires a handle, not a raw buffer
	// it will increase the size of the handle if needed
	Handle buf = NewHandle(256);
	int r = GetScrap(buf, 'TEXT', 0);

	if (r > 0)
	{
		ssh_write(*buf, r);
	}

	DisposeHandle(buf);
}

/* returns 1 if quit selected, else 0 */
int process_menu_select(int32_t result)
{
	int exit = 0;
	int16_t menu = (result & 0xFFFF0000) >> 16;
	int16_t item = (result & 0x0000FFFF);
	Str255 name;

	switch (menu)
	{
		case MENU_APPLE:
			if (item == 1)
			{
				display_about_box();
			}
			else
			{
				GetMenuItemText(GetMenuHandle(menu), item, name);
				OpenDeskAcc(name);
			}
			break;

		case MENU_FILE:
			if (item == 1) exit = 1;
			break;

		case MENU_EDIT:
			if (item == 5) ssh_paste();
			break;

		default:
			break;
	}

	HiliteMenu(0);
	return exit;
}

void event_loop(void)
{
	int exit_event_loop = 0;
	EventRecord event;
	WindowPtr eventWin;

	// maximum length of time to sleep (in ticks)
	// GetCaretTime gets the number of ticks between caret on/off time
	long int sleep_time = GetCaretTime() / 4;

	do
	{
		// wait to get a GUI event
		while (!WaitNextEvent(everyEvent, &event, sleep_time, NULL))
		{
			// timed out without any GUI events
			// toggle our cursor if needed
			check_cursor();

			// then let any other threads run before we wait for events again
			YieldToAnyThread();
		}

		// might need to toggle our cursor even if we got an event
		check_cursor();

		// handle any mac gui events
		char c = 0;
		int r = 0;
		switch(event.what)
		{
			case updateEvt:
				eventWin = (WindowPtr)event.message;
				BeginUpdate(eventWin);
				draw_screen(&(eventWin->portRect));
				EndUpdate(eventWin);
				break;

			case keyDown:
			case autoKey: // autokey means we're repeating a held down key event
				c = event.message & charCodeMask;
				// if we have a key and command and it's not autorepeating
				if (c && (event.modifiers & cmdKey) && event.what != autoKey)
				{
					switch(c)
					{
						case 'q':
							exit_event_loop = 1;
							break;
						case 'v':
							ssh_paste();
							break;
						default:
							break;
					}
				}
				else if (c)
				{
					if ('\r' == c) c = '\n';
					ssh_con.send_buffer[0] = c;
					ssh_write(ssh_con.send_buffer, 1);
				}

			case mouseDown:
				switch(FindWindow(event.where, &eventWin))
				{
					case inDrag:
						// allow the window to be dragged anywhere on any monitor
						// hmmm... which of these is better???
						DragWindow(eventWin, event.where, &(*(GetGrayRgn()))->rgnBBox);
						//	DragWindow(eventWin, event.where, &(*qd.thePort->visRgn)->rgnBBox);
						break;

					case inGrow:
						{
							//not allowing resize right now
							break;
							/*long growResult = GrowWindow(eventWin, event.where, &window_limits);
							SizeWindow(eventWin, growResult & 0xFFFF, growResult >> 16, true);
							EraseRect(&(eventWin->portRect));
							InvalRect(&(eventWin->portRect));*/
						}
						break;

					case inGoAway:
						{
							if (TrackGoAway(eventWin, event.where))
								exit_event_loop = 1;
						}
						break;

					case inMenuBar:
						exit_event_loop = process_menu_select(MenuSelect(event.where));
						break;

					case inSysWindow:
						// is this system6 relevant only???
						SystemClick(&event, eventWin);
						break;

					case inContent:
						break;
				}
				break;
		}
	} while (!exit_event_loop);
}

int init_connection(char* hostname)
{
	int rc;

	// OT vars
	OSStatus err = noErr;
	TCall sndCall;
	DNSAddress hostDNSAddress;
	OSStatus result;

	printf_i("opening and configuring endpoint... "); YieldToAnyThread();

	// open TCP endpoint
	ssh_con.endpoint = OTOpenEndpoint(OTCreateConfiguration(kTCPName), 0, nil, &err);

	if (err != noErr || ssh_con.endpoint == kOTInvalidEndpointRef)
	{
		printf_i("failed to open OT TCP endpoint\n");
		return 0;
	}

	OT_CHECK(OTSetSynchronous(ssh_con.endpoint));
	OT_CHECK(OTSetBlocking(ssh_con.endpoint));
	OT_CHECK(OTUseSyncIdleEvents(ssh_con.endpoint, false));


	OT_CHECK(OTBind(ssh_con.endpoint, nil, nil));

	OT_CHECK(OTSetNonBlocking(ssh_con.endpoint));

	printf_i("done.\n"); YieldToAnyThread();

	// set up address struct, do the DNS lookup, and connect
	OTMemzero(&sndCall, sizeof(TCall));

	sndCall.addr.buf = (UInt8 *) &hostDNSAddress;
	sndCall.addr.len = OTInitDNSAddress(&hostDNSAddress, (char *) hostname);

	printf_i("connecting endpoint... "); YieldToAnyThread();
	OT_CHECK(OTConnect(ssh_con.endpoint, &sndCall, nil));

	printf_i("done.\n"); YieldToAnyThread();

	printf_i("initializing SSH... "); YieldToAnyThread();
	// init libssh2
	SSH_CHECK(libssh2_init(0));

	printf_i("done.\n"); YieldToAnyThread();

	printf_i("opening SSH session... "); YieldToAnyThread();
	ssh_con.session = libssh2_session_init();
	if (ssh_con.session == 0)
	{
		printf_i("failed to initialize SSH library\n");
		return 0;
	}
	printf_i("done.\n"); YieldToAnyThread();

	long s = TickCount();
	printf_i("beginning SSH session handshake... "); YieldToAnyThread();
	SSH_CHECK(libssh2_session_handshake(ssh_con.session, ssh_con.endpoint));

	printf_i("done. (%d ticks)\n", TickCount() - s); YieldToAnyThread();

	read_thread_state = OPEN;

	return 1;
}

int ssh_password_auth(char* username, char* password)
{
	OSStatus err = noErr;
	int rc = 1;

	SSH_CHECK(libssh2_userauth_password(ssh_con.session, username, password));
	ssh_con.channel = libssh2_channel_open_session(ssh_con.session);

	return 1;
}

int ssh_setup_terminal(void)
{
	int rc = 0;

	SSH_CHECK(libssh2_channel_request_pty(ssh_con.channel, SSHEVEN_TERMINAL_TYPE));
	SSH_CHECK(libssh2_channel_shell(ssh_con.channel));

	return 1;
}

int intro_dialog(char* hostname, char* username, char* password)
{

	// modal dialog setup
	TEInit();
	InitDialogs(NULL);
	DialogPtr dlg = GetNewDialog(DLOG_CONNECT, 0, (WindowPtr)-1);
	InitCursor();

	// select all text in dialog item 4 (the hostname+port one)
	SelectDialogItemText(dlg, 4, 0, 32767);

	DialogItemType type;
	Handle itemH;
	Rect box;

	// draw default button indicator around the connect button
	GetDialogItem(dlg, 2, &type, &itemH, &box);
	SetDialogItem(dlg, 2, type, (Handle) NewUserItemUPP(&ButtonFrameProc), &box);

	// get the handles for each of the text boxes
	ControlHandle address_text_box;
	GetDialogItem(dlg, 4, &type, &itemH, &box);
	address_text_box = (ControlHandle)itemH;

	ControlHandle username_text_box;
	GetDialogItem(dlg, 6, &type, &itemH, &box);
	username_text_box = (ControlHandle)itemH;

	ControlHandle password_text_box;
	GetDialogItem(dlg, 8, &type, &itemH, &box);
	password_text_box = (ControlHandle)itemH;

	// let the modalmanager do everything
	// stop when the connect button is hit
	short item;
	do {
		ModalDialog(NULL, &item);
	} while(item != 1 && item != 9);

	// copy the text out of the boxes
	GetDialogItemText((Handle)address_text_box, hostname);
	GetDialogItemText((Handle)username_text_box, username);
	GetDialogItemText((Handle)password_text_box, password);

	// clean it up
	CloseDialog(dlg);
	FlushEvents(everyEvent, -1);

	// if we hit cancel, 0
	if (item == 9) return 0; else return 1;
}

//enum { WAIT, READ, EXIT } read_thread_command = WAIT;
//enum { UNITIALIZED, OPEN, CLEANUP, DONE } read_thread_state = UNITIALIZED;

// TODO: threads
void* read_thread(void* arg)
{
	int ok = 1;

	while (read_thread_command == WAIT) YieldToAnyThread();

	if (read_thread_command == EXIT)
	{
		return 0;
	}

	// connect and log in
	ok = init_connection(hostname+1);
	YieldToAnyThread();

	if (ok)
	{
		printf_i("authenticating... "); YieldToAnyThread();
		ok = ssh_password_auth(username+1, password+1);
		printf_i("done.\n"); YieldToAnyThread();
	}

	if (ok)
	{
		ok = ssh_setup_terminal();
		YieldToAnyThread();
	}

	// if we failed, exit
	if (read_thread_state != OPEN) return 0;

	// loop as long until we've failed or are asked to EXIT
	while (read_thread_command == READ && read_thread_state == OPEN)
	{
		check_network_events();
		YieldToAnyThread();
	}

	// if we still have a connection, close it
	if (read_thread_state != DONE) end_connection();

	return 0;
}

int safety_checks(void)
{
	OSStatus err;

	// check for thread manager
	long int thread_manager_gestalt = 0;
	err = Gestalt(gestaltThreadMgrAttr, &thread_manager_gestalt);

	// bit one is prescence of thread manager
	if (err != noErr || (thread_manager_gestalt & (1 << gestaltThreadMgrPresent)) == 0)
	{
		StopAlert(ALRT_TM, nil);
		printf_i("Thread Manager not available!\n");
		return 0;
	}

	// check for Open Transport

	// for some reason, the docs say you shouldn't check for OT via the gestalt
	// in an application, and should just try to init, but checking seems more
	// user-friendly, so...

	long int open_transport_any_version = 0;
	long int open_transport_new_version = 0;
	err = Gestalt(gestaltOpenTpt, &open_transport_any_version);

	if (err != noErr)
	{
		printf_i("Failed to check for Open Transport!\n");
		return 0;
	}

	err = Gestalt(gestaltOpenTptVersions, &open_transport_new_version);

	if (err != noErr)
	{
		printf_i("Failed to check for Open Transport!\n");
		return 0;
	}

	if (open_transport_any_version == 0 && open_transport_new_version == 0)
	{
		printf_i("Open Transport required but not found!\n");
		StopAlert(ALRT_OT, nil);
		return 0;
	}

	if (open_transport_any_version != 0 && open_transport_new_version == 0)
	{
		printf_i("Early version of Open Transport detected!");
		printf_i("  Attempting to continue anyway.\n");
	}

	NumVersion* ot_version = (NumVersion*) &open_transport_new_version;

	printf_i("Detected Open Transport version: %d.%d.%d\n",
		(int)ot_version->majorRev,
		(int)((ot_version->minorAndBugRev & 0xF0) >> 4),
		(int)(ot_version->minorAndBugRev & 0x0F));

	// check for CPU type and display warning if it's going to be too slow
	long int cpu_type = 0;
	int cpu_slow = 0;
	int cpu_bad = 0;
	err = Gestalt(gestaltNativeCPUtype, &cpu_type);
	if (err != noErr || cpu_type == 0)
	{
		// earlier than 7.5, need to use other gestalt
		err = Gestalt(gestaltProcessorType, &cpu_type);
		if (err != noErr || cpu_type == 0)
		{
			cpu_slow = 1;
			printf_i("Failed to detect CPU type, continuing anyway.\n");
		}
		else
		{
			if (cpu_type <= gestalt68010) cpu_bad = 1;
			if (cpu_type <= gestalt68030) cpu_slow = 1;
		}
	}
	else
	{
		if (cpu_type <= gestaltCPU68010) cpu_bad = 1;
		if (cpu_type <= gestaltCPU68030) cpu_slow = 1;
	}

	// if we don't have at least a 68020, stop
	if (cpu_bad)
	{
		StopAlert(ALRT_CPU_BAD, nil);
		return 0;
	}

	// if we don't have at least a 68040, warn
	if (cpu_slow)
	{
		CautionAlert(ALRT_CPU_SLOW, nil);
	}

	return 1;
}

int main(int argc, char** argv)
{
	OSStatus err = noErr;

	// expands the application heap to its maximum requested size
	// supposedly good for performance
	// also required before creating threads!
	MaxApplZone();

	// "Call the MoreMasters procedure several times at the beginning of your program"
	MoreMasters();
	MoreMasters();

	// general gui setup
	InitGraf(&qd.thePort);
	InitFonts();
	InitWindows();
	InitMenus();

	void* menu = GetNewMBar(MBAR_SSHEVEN);
	SetMenuBar(menu);
	AppendResMenu(GetMenuHandle(MENU_APPLE), 'DRVR');

	// disable stuff in edit menu until we implement it
	menu = GetMenuHandle(MENU_EDIT);
	DisableItem(menu, 1);
	DisableItem(menu, 3);
	DisableItem(menu, 4);
	DisableItem(menu, 6);
	DisableItem(menu, 7);
	DisableItem(menu, 9);

	DrawMenuBar();

	console_setup();

	char* logo = "   _____ _____ _    _\n"
		"  / ____/ ____| |  | |\n"
		" | (___| (___ | |__| | _____   _____ _ __\n"
		"  \\___ \\\\___ \\|  __  |/ _ \\ \\ / / _ \\ '_ \\\n"
		"  ____) |___) | |  | |  __/\\ V /  __/ | | |\n"
		" |_____/_____/|_|  |_|\\___| \\_/ \\___|_| |_|\n";

	printf_i(logo);
	printf_i("by cy384, version " SSHEVEN_VERSION "\n");

	BeginUpdate(con.win);
	draw_screen(&(con.win->portRect));
	EndUpdate(con.win);

	int ok = 1;

	if (!safety_checks()) return 0;

	BeginUpdate(con.win);
	draw_screen(&(con.win->portRect));
	EndUpdate(con.win);

	if (!intro_dialog(hostname, username, password)) ok = 0;

	if (ok)
	{
		if (InitOpenTransport() != noErr)
		{
			printf_i("failed to initialize OT\n");
			ok = 0;
		}
	}

	if (ok)
	{
		ssh_con.recv_buffer = OTAllocMem(SSHEVEN_BUFFER_SIZE);
		ssh_con.send_buffer = OTAllocMem(SSHEVEN_BUFFER_SIZE);

		if (ssh_con.recv_buffer == NULL || ssh_con.send_buffer == NULL)
		{
			printf_i("failed to allocate network buffers\n");
			ok = 0;
		}
	}

	// create the network read/print thread
	read_thread_command = WAIT;
	int read_thread_result = 0;
	ThreadID read_thread_id = 0;

	if (ok)
	{
		err = NewThread(kCooperativeThread, read_thread, NULL, 100000, kCreateIfNeeded, NULL, &read_thread_id);

		if (err < 0)
		{
			ok = 0;
			printf_i("failed to create network read thread\n");
		}
	}

	// if we got the thread, tell it to begin operation
	if (ok) read_thread_command = READ;

	// procede into our main event loop
	event_loop();

	// tell the read thread to quit, then let it run to actually do so
	read_thread_command = EXIT;
	YieldToAnyThread();

	//OTCancelSynchronousCalls(ssh_con.endpoint, kOTCanceledErr);
	//YieldToThread(read_thread_id);
	//	err = DisposeThread(read_thread_id, (void*)&read_thread_result, 0);
	//err = DisposeThread(read_thread_id, NULL, 0);

	if (ok) end_connection();

	BeginUpdate(con.win);
	draw_screen(&(con.win->portRect));
	EndUpdate(con.win);

	if (ssh_con.recv_buffer != NULL) OTFreeMem(ssh_con.recv_buffer);
	if (ssh_con.send_buffer != NULL) OTFreeMem(ssh_con.send_buffer);

	if (ok)
	{
		err = OTCancelSynchronousCalls(ssh_con.endpoint, kOTCanceledErr);
		CloseOpenTransport();
	}
}