#include "stdafx.h"

static HANDLE hDBEventPreAdd, hDBEventAdded, hContactSettingChanged;
static mir_cs RemoveChainCS;
static UINT_PTR timerId = 0;

struct DeleteEventNode {
	DeleteEventNode *next;
	time_t timestamp;
	MCONTACT hContact;
	MEVENT hDbEvent;
};
struct DeleteEventHead {
	DeleteEventNode *first;
	DeleteEventNode *last;
};
static DeleteEventHead DeleteEvents = {nullptr,nullptr};

void CALLBACK DeleteTimerProc(HWND, UINT, UINT_PTR, DWORD) {
	if (!DeleteEvents.first) return;
	mir_cslock lck(RemoveChainCS);
	DeleteEventNode *prev =nullptr, *current, *next;
	DBEVENTINFO info = {};
	next = DeleteEvents.first;
	while (current = next) {
		if (difftime(time(0), current->timestamp) < 1) break;
		if (!db_event_get(current->hDbEvent, &info)) // && info.flags&DBEF_READ)
		{
			db_event_delete(current->hDbEvent);
			next = current->next;
			if (prev) prev->next = next;
			else if (DeleteEvents.first == current) DeleteEvents.first = next;
			delete current;
		}
		else {
			prev = current;
			next = current->next;
		}
	}
	if (!DeleteEvents.first) DeleteEvents.last = nullptr;
}


// add prefix to sent messages
int OnDatabaseEventPreAdd(WPARAM hContact, LPARAM lParam)
{
	if (!options.prefix_messages || !lParam)
		return 0;

	DBEVENTINFO *dbei = (DBEVENTINFO *)lParam;
	if ((dbei->eventType != EVENTTYPE_MESSAGE) || !(dbei->flags & DBEF_SENT) || (dbei->flags & DBEF_OTR_PREFIXED))
		return 0;

	if (dbei->cbBlob == 0 || dbei->pBlob == nullptr)
		return 0; // just to be safe

	const char *proto = Proto_GetBaseAccountName(hContact);
	if (!proto)
		return 0;
	if (Contact::IsGroupChat(hContact, proto))
		return 0;

	if (mir_strcmp(proto, META_PROTO) == 0) {
		hContact = db_mc_getMostOnline(hContact);
		if (!hContact)
			return 0;
		proto = Proto_GetBaseAccountName(hContact);
		if (!proto)
			return 0;
	}

	ConnContext *context = otrl_context_find_miranda(otr_user_state, hContact);	
	bool encrypted = otr_context_get_trust(context) != TRUST_NOT_PRIVATE;
	if (!encrypted)
		return 0;
	
	DBEVENTINFO my_dbei = *dbei; // copy the other event

	char *msg = (char*)dbei->pBlob;
	int msgLen = (int)strlen(msg);

	int prefixlen = (int)strnlen(options.prefix, 64);
	if (strncmp(msg, options.prefix, prefixlen) == 0)
		return 0;

	// check for additional data presence
	int datalen = dbei->cbBlob - msgLen;
	if (datalen < 0)
		datalen = 0;

	CMStringA buf;
	buf.Append(options.prefix, prefixlen);
	buf.Append(msg);
	// append additional data
	if (datalen) {
		buf.AppendChar(0);
		buf.Append(msg + msgLen + 1, datalen);
	}
	
	my_dbei.pBlob = buf.GetBuffer();
	my_dbei.cbBlob = buf.GetLength();
	my_dbei.flags |= DBEF_OTR_PREFIXED;
	db_event_add(hContact, &my_dbei);
	
	// stop original event from being added
	return 1;
}

int OnDatabaseEventAdded(WPARAM hContact, LPARAM lParam)
{
	if (!options.delete_history)
		return 0;

	unsigned len = (unsigned)strlen(LANG_INLINE_PREFIX);

	DBEVENTINFO info = {};
	info.cbBlob = len * 2;
	info.pBlob = (char *)_alloca(info.cbBlob);
	if (db_event_get(lParam, &info))
		return 0;

	if (info.eventType != EVENTTYPE_MESSAGE)
		return 0;

	MCONTACT hSub;
	if ((hSub = db_mc_getMostOnline(hContact)) != 0)
		hContact = hSub;

	ConnContext *context = otrl_context_find_miranda(otr_user_state, hContact);
	if (context && otr_context_get_trust(context) != TRUST_NOT_PRIVATE) {
		// only delete encrypted messages that are no OTR system messages
		if (options.delete_systeminfo || !(info.cbBlob > len && !strncmp((char*)info.pBlob, LANG_INLINE_PREFIX, len))) {
			DeleteEventNode *node = new DeleteEventNode();
			node->hContact = hContact;
			node->hDbEvent = lParam;
			node->timestamp = time(0);
			node->next = nullptr;
			mir_cslock lck(RemoveChainCS);
			if (DeleteEvents.last)
				DeleteEvents.last->next = node;
			else
				DeleteEvents.first = node;
			DeleteEvents.last = node;
		}
	}
	return 0;
}

void FinishSession(MCONTACT hContact)
{
	if (!hContact)
		return;

	ConnContext *context = otrl_context_find_miranda(otr_user_state, hContact);
	TrustLevel level = otr_context_get_trust(context);
	if (level == TRUST_UNVERIFIED || level == TRUST_PRIVATE) {
		otrl_context_force_finished(context);
		//SetEncryptionStatus(hContact, TRUST_FINISHED);
		otr_gui_gone_insecure(context->app_data, context);
		//otrl_message_disconnect(otr_user_state, &ops, hContact, context->accountname, context->protocol, context->username);
		//SetEncryptionStatus(hContact, TRUST_NOT_PRIVATE);
	}
	return;
}

int WindowEvent(WPARAM uType, LPARAM lParam)
{
	auto *pDlg = (CSrmmBaseDialog *)lParam;

	if (uType == MSG_WINDOW_EVT_CLOSE && options.end_window_close) {
		FinishSession(pDlg->m_hContact);
		return 0;
	}

	if (uType != MSG_WINDOW_EVT_OPEN)
		return 0;

	MCONTACT hContact = pDlg->m_hContact, hTemp;
	if ((hTemp = db_mc_getMostOnline(hContact)) != 0)
		hContact = hTemp;

	if (!Proto_IsProtoOnContact(hContact, MODULENAME))
		return 0;

	ConnContext *context;
	{
		mir_cslock lck(lib_cs);
		context = otrl_context_find_miranda(otr_user_state, hContact);
	}
	SetEncryptionStatus(hContact, otr_context_get_trust(context));
	return 0;
}

// if it's a protocol going offline, attempt to send terminate session to all contacts of that protocol
// (this would be hooked as the ME_CLIST_STATUSMODECHANGE handler except that event is sent *after* the proto goes offline)
int StatusModeChange(WPARAM wParam, LPARAM lParam)
{
	int status = (int)wParam;
	if (status != ID_STATUS_OFFLINE)
		return 0;

	const char *proto = (char *)lParam;

	mir_cslock lck(lib_cs);

	ConnContext *context = otr_user_state->context_root;
	while (context) {
		if (context->msgstate == OTRL_MSGSTATE_ENCRYPTED && (proto == nullptr || mir_strcmp(proto, context->protocol) == 0)) {
			MCONTACT hContact = (UINT_PTR)context->app_data;

			if (hContact) {
				otrl_message_disconnect(otr_user_state, &ops, (void*)hContact, context->accountname, context->protocol, context->username, OTRL_INSTAG_BEST);
				SetEncryptionStatus(hContact, TRUST_NOT_PRIVATE);
			}

		}
		context = context->next;
	}

	return 0;
}

int OnContactSettingChanged(WPARAM hContact, LPARAM lParam)
{
	if (!options.end_offline)
		return 0;

	DBCONTACTWRITESETTING *cws = (DBCONTACTWRITESETTING *)lParam;
	if (!lParam || strcmp(cws->szSetting, "Status") != 0) return 0;
	int status = 0;
	switch (cws->value.type) {
	case DBVT_WORD:
		status = cws->value.wVal;
		break;
	case DBVT_BYTE:
		status = cws->value.bVal;
		break;
	case DBVT_DWORD:
		status = cws->value.dVal;
		break;
	}

	if (status == ID_STATUS_OFFLINE) {
		if (!hContact) {
			// Protocol is going offline
			// Terminate sessions with all contacts of that proto
			StatusModeChange((WPARAM)ID_STATUS_OFFLINE, (LPARAM)cws->szModule);
			return 0;
		}
		if (Proto_IsProtoOnContact(hContact, MODULENAME)) {
			// only care about contacts to which this filter is attached
			FinishSession(hContact);
		}
	}

	return 0;
}

void InitDBFilter()
{
	hDBEventPreAdd = HookEvent(ME_DB_EVENT_FILTER_ADD, OnDatabaseEventPreAdd);
	hDBEventAdded = HookEvent(ME_DB_EVENT_ADDED, OnDatabaseEventAdded);
	hContactSettingChanged = HookEvent(ME_DB_CONTACT_SETTINGCHANGED, OnContactSettingChanged);
	timerId = SetTimer(nullptr, 0, 1000, DeleteTimerProc);
}

void DeinitDBFilter()
{
	UnhookEvent(hDBEventPreAdd);
	hDBEventPreAdd = nullptr;
	UnhookEvent(hDBEventAdded);
	hDBEventAdded = nullptr;
	UnhookEvent(hContactSettingChanged);
	hContactSettingChanged = nullptr;
	if (timerId) KillTimer(nullptr, timerId);
	DeleteTimerProc(nullptr, 0, 0, 0);
}