/*
 * Copyright (c) 2023 Valtteri Koskivuori <vkoskiv@gmail.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*
TODO:
- Display possible errors in cdev
*/

#include <SetUpA4.h>
#include <GestaltEqu.h>
#include "MacNTP.h"
#include "ShowInitIcon.h"
#include "rsrcid.h"

// This enables DebugStr() printouts to aid development.
// This also disables the system time check, so it tries NTP
// on every boot.
//#define DEBUGGING

void dump_error(enum MacNTPError error, OSErr oserror);
int TryMacNTP(Str255 ntp1, Str255 ntp2, Str255 utc);
int is_number(char c);
int validate_utc(Str255 utc_str);
int utcstr_to_mins(Str255 utc, long *out);

#define SECONDS_TO_02_09_1996 2924510400ul

Handle g_mtcp_init_handle;

void dump_error(enum MacNTPError error, OSErr oserror) {
	Str255 numstr;
	StringHandle err_str;
	err_str = GetString(ERR_STR_ID);
	if (!err_str) {
		SysBeep(10);
		SysBeep(1);
		return;
	}
	SetHandleSize(err_str, 256);
	HLock(err_str);
	NumToString(oserror, numstr);
	switch (error) {
		case Success:
			SetString(err_str, "\p"); //FIXME: Bit dumb to write this every time?
			break;
		case MacTCPInitFailed:
			SetString(err_str, "\pMacTCP init failed");
			break;
		case InvalidURL:
			SetString(err_str, "\pInvalid URL");
			break;
		case BadNtpStructSize:
			SetString(err_str, "\pBad NTP struct size");
			break;
		case UDPCreateFailed:
			SetString(err_str, "\pUDPCreate failed");
			break;
		case UDPSendFailed:
			SetString(err_str, "\pUDPSend failed");
			break;
		case UDPRcvFailed:
			SetString(err_str, "\pUDPRcv failed");
			break;
		case InvalidNTPResponse:
			SetString(err_str, "\pInvalid NTP response");
			break;
		case OriginTimestampMismatch:
			SetString(err_str, "\pOrigin timestamp mismatch");
			break;
		case DNSResolveFailed:
			SetString(err_str, "\pDNS resolve failed");
			break;
		case ClockWriteFailed:
			SetString(err_str, "\pClock write failed");
			break;
		case ClockReadFailed:
			SetString(err_str, "\pClock read failed");
			break;
		case UDPRcvTimedOut:
			SetString(err_str, "\pUDPRcv timed out");
			break;
		case PacketParamNull:
			SetString(err_str, "\pPacket param null");
			break;
	}
	HUnlock(err_str);
	ChangedResource(err_str);
	ReleaseResource(err_str);
	UpdateResFile(CurResFile());
}

//FIXME: This is duplicated from cdev.c, but I didn't want to
//make a library and all the extra build steps just for this.
//Maybe we'll just stick it in MacNTPLib and figure out linkage somehow
int is_number(char c) {
	return c >> 4 == 3 && (c & 0x0F) < 0xA;
}

int validate_utc(Str255 utc_str) {
	// Str255 is a pointer to a pascal string, where
	// the first byte is the string length.
	char scratch[6];
	short strlen;
	char *str;
	strlen = utc_str[0];
	str = (char *)&utc_str[1];
	if (strlen != 6) return false;
	if (str[0] != '+' && str[0] != '-') return false;
	if (!is_number(str[1]) || !is_number(str[2])) return false;
	if (str[3] != ':') return false;
	if (!is_number(str[4]) || !is_number(str[5])) return false;
	
	return true;
}
int utcstr_to_mins(Str255 utc, long *out) {
	long minutes;
	if (!validate_utc(utc)) return false;
	minutes = 0;
	minutes += ((utc[2] - 0x30) * 10) * 60;
	minutes += (utc[3] - 0x30) * 60;
	minutes += (utc[5] - 0x30) * 10;
	minutes += (utc[6] - 0x30);
	if (utc[1] == '-')
		minutes = -minutes;
	if (out) *out = minutes;
	return true;
}

int TryMacNTP(Str255 ntp1, Str255 ntp2, Str255 utc) {
	struct ntp_packet payload;
	enum MacNTPError error;
	OSErr oserr = 0;
	minutes_t utc_offset;
	
	if (!utc[0]) return 1;
	if (!utcstr_to_mins(utc, &utc_offset)) return 1;
	
	if (!ntp1[0]) return 1;
	PtoCstr(ntp1);
	error = MacNTPFetchTime((char *)(ntp1), &payload, &oserr, utc_offset);
	if (error == DNSResolveFailed) SysBeep(1);
	// If the first lookup fails and we have a fallback, try it.
	if (error == DNSResolveFailed && ntp2[0]) {
		PtoCstr(ntp2);
		error = MacNTPFetchTime((char *)(ntp2), &payload, &oserr, utc_offset);
	}
	dump_error(error, oserr);
	if (error) return 1;
	
	error = MacNTPSetSystemTime(&payload, utc_offset);
	dump_error(error, oserr);
	if (error) return 1;
	return 0;
}

void main() {
	Ptr our_init_ptr;
	unsigned long systime;
	StringHandle ntp1;
	StringHandle ntp2;
	StringHandle utc; // Offset in minutes as pstr
	long answer;
	OSErr gestalt_err;
	asm {
		move.L A0, our_init_ptr;
	}
	RememberA0();
	SetUpA4();
	// This is already locked in the resource attrs
	g_mtcp_init_handle = RecoverHandle(our_init_ptr);
	
	// First we check if MacTCP is available
	// This also assumes Gestalt support
	gestalt_err = Gestalt(gestaltVersion, &answer);
	if (gestalt_err) {
		// Gestalt not available, it was introduced in 6.0.4
		// And MacTCP in 6.0.3, so we're just going to assume
		// the user has at least 6.0.8
		ShowInitIcon(MACNTP_ICN_ID_FAILURE, true);
		goto skip;
	}
	
	if (Gestalt('mtcp', nil)) {
		// MacTCP not found
		ShowInitIcon(MACNTP_ICN_ID_FAILURE, true);
		goto skip;
	}
	
	ntp1 = GetString(NTP1_STR_ID);
	ntp2 = GetString(NTP2_STR_ID);
	utc  = GetString(UTC_STR_ID);
	if (!ntp1 || !ntp2 || !utc) {
#ifdef DEBUGGING
		DebugStr("\pSTR rsrcs missing");
#endif
		ShowInitIcon(MACNTP_ICN_ID_FAILURE, true);
		goto skip;
	}
	/*if (!*ntp1[0] && !*ntp2[0]) {
#ifdef DEBUGGING
		DebugStr("\pBoth NTP urls empty");
#endif
		ShowInitIcon(MACNTP_ICN_ID_FAILURE, true);
		goto skip;
	}*/
	HLock(ntp1);
	HLock(ntp2);
	HLock(utc);
	
	//TODO: Move this up a bit
#ifndef DEBUGGING
	// We only try to update the clock if we're well into the 20th century
	ReadDateTime((unsigned long *)&systime);
	if (systime > SECONDS_TO_02_09_1996) {
		ShowInitIcon(MACNTP_ICN_ID_SUCCESS, true);
		goto skip;
	} else {
		ShowInitIcon(MACNTP_ICN_ID_PENDING, false);
	}
#else
	ShowInitIcon(MACNTP_ICN_ID_PENDING, false);
#endif
	
	if (!TryMacNTP(*ntp1, *ntp2, *utc)) {
		ShowInitIcon(MACNTP_ICN_ID_SUCCESS, true);
	} else {
		ShowInitIcon(MACNTP_ICN_ID_FAILURE, true);
	}
	
	// I have no idea if unlock is needed here. Maybe not.
	HUnlock(ntp1);
	//DisposHandle(ntp1);
	HUnlock(ntp2);
	// For whatever reason, System 6 crashes on boot if we
	// try to dispose this specific handle. Okay.
	//DisposHandle(ntp2);
	HUnlock(utc);
	//DisposHandle(utc);
	HUnlock(g_mtcp_init_handle);
skip:
error:
	RestoreA4();
}