local _;


-- for saving once learnt yards in saved variables
local VUHDO_STORED_ZONES = { };
local VUHDO_CLUSTER_BLACKLIST = { };
local VUHDO_RAID = {};

local sqrt = sqrt;
local CheckInteractDistance = CheckInteractDistance;
local WorldMapFrame = WorldMapFrame;
local GetMouseFocus = GetMouseFocus;
local pairs = pairs;
local GetTime = GetTime;
local GetSpellCooldown = GetSpellCooldown;
local twipe = table.wipe;
local tsort = table.sort;
local VUHDO_setMapToCurrentZone;
local VUHDO_tableUniqueAdd;

local VUHDO_COORD_DELTAS = { };
setmetatable(VUHDO_COORD_DELTAS, VUHDO_META_NEW_ARRAY);

local VUHDO_MAP_WIDTH = 0;
local VUHDO_LAST_ZONE = nil;

local VUHDO_MIN_TICK_UNIT = 0.000000000001;
local VUHDO_MAX_TICK_UNIT = 1;
local VUHDO_MAP_LIMIT_YARDS = 1000000;
local VUHDO_MAX_SAMPLES = 50;
local VUHDO_MAX_ITERATIONS = 120; -- For a 40 man raid there is a total of +800 iterations

--
local VUHDO_CLUSTER_BASE_RAID = { };
function VUHDO_clusterBuilderInitLocalOverrides()
	VUHDO_CLUSTER_BASE_RAID = _G["VUHDO_CLUSTER_BASE_RAID"];
	VUHDO_RAID = _G["VUHDO_RAID"];

	VUHDO_setMapToCurrentZone = _G["VUHDO_setMapToCurrentZone"];
	VUHDO_tableUniqueAdd = _G["VUHDO_tableUniqueAdd"];
end



--
local VUHDO_MAP_FIX_WIDTH = {
	["AlteracValley"] = {
		[1] = 4237.49987792969,
	},

	--[[["StormwindCity"] = {
		[0] = 1737.4999589920044,
	},]]
};



-- Inspect, Trade, Duel, UnitInRange(, UnitIsVisible? => doesn't seem to be reliable)
local VUHDO_INTERACT_MAX_DISTANCES = { VUHDO_MIN_TICK_UNIT, VUHDO_MIN_TICK_UNIT, VUHDO_MIN_TICK_UNIT, VUHDO_MIN_TICK_UNIT };
local VUHDO_INTERACT_FAIL_MIN_DISTANCES = { VUHDO_MAX_TICK_UNIT, VUHDO_MAX_TICK_UNIT, VUHDO_MAX_TICK_UNIT, VUHDO_MAX_TICK_UNIT };
local VUHDO_INTERACT_YARDS = { 28, 11.11, 9.9, 40 };



--
local function VUHDO_clusterBuilderStoreZone(aZone)
	if aZone then
		VUHDO_STORED_ZONES[aZone] = { };
		VUHDO_STORED_ZONES[aZone]["good"] = VUHDO_deepCopyTable(VUHDO_INTERACT_MAX_DISTANCES);
		VUHDO_STORED_ZONES[aZone]["fail"] = VUHDO_deepCopyTable(VUHDO_INTERACT_FAIL_MIN_DISTANCES);
	end
end



--
local tIsValid;
local function VUHDO_isValidClusterUnit(anInfo)
	tIsValid = not anInfo["dead"]	and anInfo["connected"] and anInfo["visible"];
	VUHDO_CLUSTER_BLACKLIST[anInfo["unit"]] = not tIsValid;
	return tIsValid;
end



--
local tDistance;
local tEmptyUnit = { };
local function VUHDO_calibrateMapScale(aUnit, aDeltaX, aDeltaY)
	tDistance = sqrt((aDeltaX * aDeltaX)  + ((aDeltaY * 0.6666666666666) ^ 2));

	for tCnt = 1, 3 do
		-- Check only if new distance is within bandwidth (= better result than before)
		if tDistance > VUHDO_INTERACT_MAX_DISTANCES[tCnt] and tDistance < VUHDO_INTERACT_FAIL_MIN_DISTANCES[tCnt] then
			if CheckInteractDistance(aUnit, tCnt) then
				VUHDO_INTERACT_MAX_DISTANCES[tCnt] = tDistance;
			else
				VUHDO_INTERACT_FAIL_MIN_DISTANCES[tCnt] = tDistance;
			end
			VUHDO_clusterBuilderStoreZone(VUHDO_LAST_ZONE);
		end
	end

	if tDistance > VUHDO_INTERACT_MAX_DISTANCES[4] and tDistance < VUHDO_INTERACT_FAIL_MIN_DISTANCES[4] then
		if (VUHDO_RAID[aUnit] or tEmptyUnit)["baseRange"] then
			VUHDO_INTERACT_MAX_DISTANCES[4] = tDistance;
		else
			VUHDO_INTERACT_FAIL_MIN_DISTANCES[4] = tDistance;
		end
		VUHDO_clusterBuilderStoreZone(VUHDO_LAST_ZONE);
	end
end



--
local tCurrWorldSize, tMinWorldSize, tUpperBoundary;
local function VUHDO_getHeuristicMapWidth()
	tMinWorldSize = VUHDO_MAP_LIMIT_YARDS;
	tUpperBoundary = nil;
	for tIndex, tNormFactor in pairs(VUHDO_INTERACT_YARDS) do
		tCurrWorldSize = tNormFactor / VUHDO_INTERACT_MAX_DISTANCES[tIndex]; -- yards per full tick = world size in yards

		if tCurrWorldSize < tMinWorldSize then -- Better test results are always smaller = closer to the limit of interact distance
			tMinWorldSize = tCurrWorldSize;
			if VUHDO_INTERACT_FAIL_MIN_DISTANCES[tIndex] < VUHDO_MAX_TICK_UNIT then
				tUpperBoundary = tNormFactor / VUHDO_INTERACT_FAIL_MIN_DISTANCES[tIndex];
			end
		end
	end

	return tUpperBoundary and (tMinWorldSize + tUpperBoundary) * 0.5 or tMinWorldSize;
end



--
local tX1, tY1, tX2, tY2;
local tIsValid;
local tIsInInstance;
local function VUHDO_determineDistanceBetween(aUnit, anotherUnit)
	-- as of patch 7.1 APIs related to unit position/distance do not function inside instances
	tIsInInstance, _ = IsInInstance();

	if tIsInInstance then
		return nil, nil;
	end
	
	tIsValid = true;

	-- as of patch 7.1 GetPlayerMapPosition() returns zero/nil inside certain zones
	tX1, tY1 = VUHDO_getUnitMapPosition(aUnit);
	if not tX1 or (tX1 + tY1 <= 0) then
		VUHDO_CLUSTER_BLACKLIST[aUnit] = true;
		tIsValid = false;
	end

	-- as of patch 7.1 GetPlayerMapPosition() returns zero/nil inside certain zones
	tX2, tY2 = VUHDO_getUnitMapPosition(anotherUnit);
	if not tX2 or (tX2 + tY2 <= 0) then
		VUHDO_CLUSTER_BLACKLIST[anotherUnit] = true;
		tIsValid = false;
	end

	if not tIsValid then
		return nil, nil;
	end

	return tX1 - tX2, tY1 - tY2;
end



--
local function VUHDO_clusterBuilderNewZone(anOldZone, aNewZone)
	VUHDO_clusterBuilderStoreZone(anOldZone);

	if VUHDO_STORED_ZONES[aNewZone] then
		VUHDO_INTERACT_MAX_DISTANCES = VUHDO_deepCopyTable(VUHDO_STORED_ZONES[aNewZone]["good"]);
		VUHDO_INTERACT_FAIL_MIN_DISTANCES = VUHDO_deepCopyTable(VUHDO_STORED_ZONES[aNewZone]["fail"]);
	else
		VUHDO_INTERACT_MAX_DISTANCES[1] = VUHDO_MIN_TICK_UNIT;
		VUHDO_INTERACT_MAX_DISTANCES[2] = VUHDO_MIN_TICK_UNIT;
		VUHDO_INTERACT_MAX_DISTANCES[3] = VUHDO_MIN_TICK_UNIT;
		VUHDO_INTERACT_MAX_DISTANCES[4] = VUHDO_MIN_TICK_UNIT;
		VUHDO_INTERACT_FAIL_MIN_DISTANCES[1] = VUHDO_MAX_TICK_UNIT;
		VUHDO_INTERACT_FAIL_MIN_DISTANCES[2] = VUHDO_MAX_TICK_UNIT;
		VUHDO_INTERACT_FAIL_MIN_DISTANCES[3] = VUHDO_MAX_TICK_UNIT;
		VUHDO_INTERACT_FAIL_MIN_DISTANCES[4] = VUHDO_MAX_TICK_UNIT;
	end
end



--
local tUnit, tInfo;
local tAnotherUnit, tAnotherInfo;
local tX, tY, tDeltaX, tDeltaY;
local tMaxX, tMaxY;
local tMapId, tMap, tMapFileName, tDungeonLevels, tCurrLevel;
local tCurrentZone;
local tNumRaid;
local tIndex = 0;
local tNumSamples, tNumIterations;
local tIsInInstance;
local VuhDoDummyStub = {
	["GetName"] = function() return ""; end,
	["IsForbidden"] = function() return false; end,
};

function VUHDO_updateAllClusters()

	-- as of patch 7.1 APIs related to unit position/distance do not function inside instances
	tIsInInstance, _ = IsInInstance();

	if tIsInInstance then
		return;
	end

	-- @UGLY Carbonite workaround
	local tFocusFrame = GetMouseFocus() or VuhDoDummyStub;

	-- check if our mouse focus frame is forbidden before calling any methods on it
	if tFocusFrame:IsForbidden() then
		return;
	elseif not tFocusFrame:GetName() then
		return;
	end

	if WorldMapFrame:IsShown() then
		return;
	end

	-- TODO: is this needed anymore given 8.0.1 map changes?
	--[[tX, tY = VUHDO_getUnitMapPosition("player");
	if (tX or 0) + (tY or 0) <= 0 then
		-- FIXME: calling WorldMapFrame:SetMapID produces strange results as of build 26567
		VUHDO_setMapToCurrentZone();
	end]]

	-- In 8.0.1 Blizzard introduced new C_Map APIs
	-- each map level has a unique map ID now
	-- tMapFileName will now represent simply the map name
	-- tCurrLevel will now represent the unique map ID
	-- tDungeonLevels will still group all map IDs under the same map name (e.g. old map levels)
	tMapId = C_Map.GetBestMapForUnit("player");

	if tMapId then
		tMap = C_Map.GetMapInfo(tMapId);
	end

	tMapFileName = tMap and tMap["name"] or "*";
	tCurrLevel = tMap and tMap["mapID"] or 0;
	tCurrentZone = tMapFileName .. tCurrLevel;

	if VUHDO_LAST_ZONE ~= tCurrentZone then
		VUHDO_clusterBuilderNewZone(VUHDO_LAST_ZONE, tCurrentZone);
		VUHDO_LAST_ZONE = tCurrentZone;
	end

	tNumSamples, tNumIterations = 0, 0;
	tNumRaid = #VUHDO_CLUSTER_BASE_RAID;

	while true do
		tIndex = tIndex + 1;
		if tIndex > tNumRaid then
			tIndex = 0;
			break;
		end

		tInfo = VUHDO_CLUSTER_BASE_RAID[tIndex];
		tUnit = tInfo["unit"];

		if VUHDO_isValidClusterUnit(tInfo) then
			for tCnt = tIndex + 1, tNumRaid do
				tAnotherInfo = VUHDO_CLUSTER_BASE_RAID[tCnt];

				if VUHDO_isValidClusterUnit(tAnotherInfo) then
					tAnotherUnit = tAnotherInfo["unit"];
					tDeltaX, tDeltaY = VUHDO_determineDistanceBetween(tUnit, tAnotherUnit);

					if tDeltaX then
						if not VUHDO_COORD_DELTAS[tUnit][tAnotherUnit] then
							VUHDO_COORD_DELTAS[tUnit][tAnotherUnit] = { };
						end
						VUHDO_COORD_DELTAS[tUnit][tAnotherUnit][1] = tDeltaX;
						VUHDO_COORD_DELTAS[tUnit][tAnotherUnit][2] = tDeltaY;

						-- and the other way round to reduce iterations
						if not VUHDO_COORD_DELTAS[tAnotherUnit] then
							VUHDO_COORD_DELTAS[tAnotherUnit] = { };
						end
						if not VUHDO_COORD_DELTAS[tAnotherUnit][tUnit] then
							VUHDO_COORD_DELTAS[tAnotherUnit][tUnit] = { };
						end
						VUHDO_COORD_DELTAS[tAnotherUnit][tUnit][1] = tDeltaX;
						VUHDO_COORD_DELTAS[tAnotherUnit][tUnit][2] = tDeltaY;

						tNumSamples = tNumSamples + 1;
						if tNumSamples > 50 then break; end -- VUHDO_MAX_SAMPLES
					end
				end
				tNumIterations = tNumIterations + 1;
				if tNumIterations > 120 then break; end -- VUHDO_MAX_ITERATIONS
			end -- for
		else -- Blacklist updaten
			for tCnt = tIndex + 1, tNumRaid do
				tAnotherInfo = VUHDO_CLUSTER_BASE_RAID[tCnt];
				if not tAnotherInfo then break;	end
				VUHDO_isValidClusterUnit(tAnotherInfo);
			end
		end

		if tNumSamples > 50 or tNumIterations > 120 then break; end -- VUHDO_MAX_SAMPLES -- VUHDO_MAX_ITERATIONS
	end

	tMaxX = nil;

	-- Try to determine well known dungeons
	tDungeonLevels = VUHDO_MAP_FIX_WIDTH[tMapFileName];
	if tDungeonLevels then
		tMaxX = tDungeonLevels[tCurrLevel];
	end

	-- Otherwise get from heuristic database
	if (tMaxX or 0) == 0 then
		if VUHDO_COORD_DELTAS["player"] then
			for tUnit, tDeltas in pairs(VUHDO_COORD_DELTAS["player"]) do
				VUHDO_calibrateMapScale(tUnit, tDeltas[1], tDeltas[2]);
			end
		end

		tMaxX = VUHDO_getHeuristicMapWidth();

		-- Unreasonable?
		if tMaxX < 1 or tMaxX >= VUHDO_MAP_LIMIT_YARDS then
			VUHDO_MAP_WIDTH = 0;
			return;
		end
	end

--	if (VUHDO_MAP_WIDTH ~= tMaxX) then
--		VUHDO_Msg("Map approx yards changed from " .. floor(VUHDO_MAP_WIDTH * 10) / 10 .. " to " .. floor(tMaxX * 10) / 10);
--	end

	VUHDO_MAP_WIDTH = tMaxX;
end



--
function VUHDO_resetClusterCoordDeltas()
	twipe(VUHDO_COORD_DELTAS);
end



--
local function VUHDO_sortClusterComparator(aUnit, anotherUnit)
	return VUHDO_RAID[aUnit]["healthmax"] - VUHDO_RAID[aUnit]["health"]
		> VUHDO_RAID[anotherUnit]["healthmax"] - VUHDO_RAID[anotherUnit]["health"];
end



--
local tDistance, tNumber, tInfo;
local tStart, tDuration;
function VUHDO_getUnitsInRadialClusterWith(aUnit, aYardsPow, anArray, aCdSpell)
	twipe(anArray);

	if aCdSpell then
		tStart, tDuration = GetSpellCooldown(aCdSpell);
		tDuration = tDuration or 0;

		if tDuration > 1.5 then -- Don't remove clusters for gcd
			tStart = tStart or 0;
			if tStart + tDuration > GetTime() then
				return anArray;
			end
		end
	end

	tInfo = VUHDO_RAID[aUnit];
	if tInfo and not VUHDO_CLUSTER_BLACKLIST[aUnit] then
		anArray[1] = aUnit;-- Source is always part of the cluster
	end
	if VUHDO_MAP_WIDTH == 0 or not VUHDO_COORD_DELTAS[aUnit] then
		return anArray;
	end

	for tOtherUnit, tDeltas in pairs(VUHDO_COORD_DELTAS[aUnit]) do
		tDistance = (((tDeltas[1] or 0) * VUHDO_MAP_WIDTH) ^ 2)  + (((tDeltas[2] or 0) * VUHDO_MAP_WIDTH / 1.5) ^ 2);
		if tDistance <= aYardsPow and not VUHDO_CLUSTER_BLACKLIST[tOtherUnit] then
			anArray[#anArray + 1] = tOtherUnit;
		end
	end

	tsort(anArray, VUHDO_sortClusterComparator);
	return anArray;
end
local VUHDO_getUnitsInRadialClusterWith = VUHDO_getUnitsInRadialClusterWith;



--
local tWinnerUnit, tInfo, tWinnerMissLife;
local tCurrMissLife;
local function VUHDO_getMostDeficitUnitOutOf(anIncludeList, anExcludeList)
	tWinnerUnit = nil;
	tWinnerMissLife = -1;

	for _, tUnit in pairs(anIncludeList) do
		if not anExcludeList[tUnit] then
			tInfo = VUHDO_RAID[tUnit];
			if tInfo and tInfo["healthmax"] - tInfo["health"] > tWinnerMissLife then
				tWinnerUnit = tUnit;
				tWinnerMissLife = tInfo["healthmax"] - tInfo["health"];
			end
		end
	end
	return tWinnerUnit;
end



--
local tNextJumps = { };
local tExcludeList = { };
local tNumJumps = 0;
function VUHDO_getUnitsInChainClusterWith(aUnit, aYardsPow, anArray, aMaxTargets, aCdSpell)
	twipe(anArray);
	twipe(tExcludeList)
	for tCnt = 1, aMaxTargets do
		anArray[tCnt] = aUnit;
		tExcludeList[aUnit] = true;
		VUHDO_getUnitsInRadialClusterWith(aUnit, aYardsPow, tNextJumps, aCdSpell);
		aUnit = VUHDO_getMostDeficitUnitOutOf(tNextJumps, tExcludeList);
		if not aUnit then break; end
	end
	return anArray;
end



--
local tDeltas, tDistance;
function VUHDO_getDistanceBetween(aUnit, anotherUnit)
	if VUHDO_CLUSTER_BLACKLIST[aUnit] or VUHDO_CLUSTER_BLACKLIST[anotherUnit] then	return nil; end

	if VUHDO_COORD_DELTAS[aUnit] and VUHDO_COORD_DELTAS[aUnit][anotherUnit] then
		tDeltas = VUHDO_COORD_DELTAS[aUnit][anotherUnit];
		return sqrt((((tDeltas[1] or 0) * VUHDO_MAP_WIDTH) ^ 2)  + (((tDeltas[2] or 0) * VUHDO_MAP_WIDTH / 1.5) ^ 2));
	end

	return nil;
end



--
local tDeltas, tXCoord, tYCoord;
local function VUHDO_getRealPosition(aUnit)
	if VUHDO_CLUSTER_BLACKLIST[aUnit] then return nil; end

	if VUHDO_COORD_DELTAS[aUnit] then
		tXCoord, tYCoord = VUHDO_getUnitMapPosition(aUnit);
		if tXCoord and tYCoord then
			return tXCoord * VUHDO_MAP_WIDTH, tYCoord * VUHDO_MAP_WIDTH / 1.5;
		end
	end

	return nil;
end

--------------------------------------------------------------------------------------------------

local VuhDoLine = { };
local sLines = { };
VuhDoLine.__index = VuhDoLine;

--
local tLine;
function VuhDoLine.create(aLineNum, aStartX, aStartY, anEndX, anEndY)
	--local tLine = { };
	if (sLines[aLineNum] == nil) then
		sLines[aLineNum] = { };
		setmetatable(sLines[aLineNum], VuhDoLine);
	end
	tLine = sLines[aLineNum];

	tLine.startX, tLine.startY, tLine.endX, tLine.endY
		= aStartX, aStartY, anEndX, anEndY;
	return tLine;
end



--
function VuhDoLine:enthaelt(anX, anY)
	return (anX >= self.startX and anX <= self.endX) or (anX <= self.startX and anX >= self.endX);
end

function VuhDoLine:hoehe()
	return self.endY - self.startY;
end

function VuhDoLine:breite()
	return self.endX - self.startX;
end

function VuhDoLine:steigung()
	return self:hoehe() / self:breite();
end

function VuhDoLine:laenge()
	return sqrt((self:hoehe() * self:hoehe()) + (self:breite() * self:breite()));
end

function VuhDoLine:achsenabschnitt()
	return self.startY - (self:steigung() * self.startX);
end


local tX;
function VuhDoLine:schnittpunkt(aLine)
	tX = (aLine:achsenabschnitt() - self:achsenabschnitt()) / (self:steigung() - aLine:steigung());
	return  tX, self:steigung() * tX + self:achsenabschnitt();
end



--
local tLineToTarget;
local tOrthogonale;
local tOrthoLaenge;
local tPlayerX, tPlayerY;
local tTargetX, tTargetY;
local tZuPruefenX, tZuPruefenY;
local tSchnittX, tSchnittY;
local tDestCluster = { };
local tNumFound;
local tUnit;
function VUHDO_getUnitsInLinearCluster(aUnit, anArray, aRange, aMaxTargets, anIsHealsPlayer, aCdSpell)
	twipe(anArray);
	twipe(tDestCluster);

	if aCdSpell then
		tStart, tDuration = GetSpellCooldown(aCdSpell);
		tDuration = tDuration or 0;

		if tDuration > 1.5 then -- Don't remove clusters for gcd
			tStart = tStart or 0;
			if tStart + tDuration > GetTime() then
				return anArray;
			end
		end
	end

	if VUHDO_MAP_WIDTH == 0 or not VUHDO_COORD_DELTAS[aUnit] then return; end

	tPlayerX, tPlayerY = VUHDO_getRealPosition("player");
	if not tPlayerX then return; end

	tTargetX, tTargetY = VUHDO_getRealPosition(aUnit);
	if not tTargetX then return; end

	tLineToTarget = VuhDoLine.create(1, tPlayerX, tPlayerY, tTargetX, tTargetY);

	for _, tInfo in pairs(VUHDO_CLUSTER_BASE_RAID) do
		tUnit = tInfo["unit"];
		if "player" ~= tUnit and not VUHDO_CLUSTER_BLACKLIST[tUnit] then
			tZuPruefenX, tZuPruefenY = VUHDO_getRealPosition(tUnit);
			if tZuPruefenX then

				tOrthogonale = VuhDoLine.create(2,
					tZuPruefenX - tLineToTarget:hoehe(),
					tZuPruefenY + tLineToTarget:breite(),
					tZuPruefenX + tLineToTarget:hoehe(),
					tZuPruefenY - tLineToTarget:breite());

				tSchnittX, tSchnittY = tOrthogonale:schnittpunkt(tLineToTarget);

				if tLineToTarget:enthaelt(tSchnittX, tSchnittY) then
					tOrthoLaenge = VuhDoLine.create(3, tZuPruefenX, tZuPruefenY,
						tSchnittX, tSchnittY);
					if tOrthoLaenge:laenge() <= aRange then
						tDestCluster[#tDestCluster + 1] = aUnit;
					end
				end
			end
		end
	end

	if anIsHealsPlayer then
		if (VUHDO_tableUniqueAdd(tDestCluster, "player")) then
			aMaxTargets = aMaxTargets + 1;
		end
	end

	tsort(tDestCluster, VUHDO_sortClusterComparator);
	tNumFound = #tDestCluster;
	for tCnt = 1, tNumFound > aMaxTargets and aMaxTargets or tNumFound do
		anArray[tCnt] = tDestCluster[tCnt];
	end
end



--
local tVector2d;
local tMapId;
function VUHDO_getUnitMapPosition(aUnit)

	if not aUnit then
		return;
	end

	-- 8.0.1 build 26567 added restrictions (must be in player's party) on which unit IDs can be queried
	tMapId = C_Map.GetBestMapForUnit(aUnit) or C_Map.GetBestMapForUnit("player");

	if not tMapId then
		return;
	end

	tVector2d = C_Map.GetPlayerMapPosition(tMapId, aUnit);

	if tVector2d then
		return tVector2d:GetXY();
	else
		return nil, nil;
	end

end

