-- LUA Script - precede every function and global member with lowercase name of script + '_main'
-- Player Enters Sound Zone
local U = require "scriptbank\\utillib"

local sqrt = math.sqrt

local drips = {}

function dripwithecho_init_name( e, name )
	Include( "utillib.lua" )

	--Hide( e )
	CollisionOff( e )
	
	if name == 'main' then
		drips[ e ] = { typ = 'main', state = 'init' }
	else
		drips[ e ] = { typ = 'echo', state = 'init' }
	end
end

local soundDist = 1500
local echoDist  = 3000
local maxSqDist = soundDist * soundDist
local sndSpeed  = 5 -- 13.5
local dripRate  = 4000

local function getDist( pos1, pos2 )
	local DX, DY, DZ = pos1.x - pos2.x, pos1.y - pos2.y, pos1.z - pos2.z
	return sqrt( DX*DX + DY*DY + DZ*DZ )
end

local function getVolume( pos1, pos2 )
	local DX, DY, DZ = pos1.x - pos2.x, pos1.y - pos2.y, pos1.z - pos2.z
	local sQdist =  DX*DX + DY*DY + DZ*DZ 
	return 60 + ( 40 * ( maxSqDist - sQdist ) / maxSqDist )
end

local function calcEchoTime( dp, ep, pp )
	local a, b, c = getDist( dp, ep ), getDist( ep, pp ), getDist( dp, pp )
	return ( a + b - c ) / sndSpeed 
end

local function makeEcho( t, pos, pp, dp )
	for k, v in pairs( drips ) do
		if v.typ == 'echo' and v.state == 'idle' then
			PositionObject( v.obj, pos.x, pos.y, pos.z )
			v.state = 'echo'
			v.timer = t + calcEchoTime( dp, pos, pp ) 
			v.pos = pos
			break
		end
	end
end

local rayCast = IntersectAll
local getColX = GetIntersectCollisionX
local getColY = GetIntersectCollisionY
local getColZ = GetIntersectCollisionZ

local function getColPos()
	return { x = getColX(), y = getColY(), z = getColZ() }
end

local directionList =
{ { x =  0, z =  1 },  -- N
  { x =  1, z =  0 },  -- E
  { x =  0, z = -1 },  -- S
  { x = -1, z =  0 }   -- W
} 
  
local function checkForEchoPoints( pos, ignObj )
	local echoList = {}
	
	for _, v in pairs( directionList ) do
	
		local ox, oy, oz = v.x * echoDist, 60, v.z * echoDist
		
		local ex, ey, ez = pos.x + ox, pos.y + oy, pos.z + oz

		local obj = rayCast( pos.x, pos.y, pos.z, ex, ey, ez, ignObj )
		
		if obj and obj ~= 0 then 
			echoList[ #echoList + 1 ] = getColPos()
		end
	end
	
	return echoList
end


function dripwithecho_main( e )

	local drip = drips[ e ]
	
	if drip == nil then return end
	
	local timeNow = g_Time
		
	local Ent = g_Entity[ e ]
	
	if drip.state == 'init' then
			
		drip.state = 'idle'
		drip.pos   = { x = Ent.x, y = Ent.y, z = Ent.z }
		drip.timer = 0 
		drip.obj   = Ent.obj
		
	elseif
       drip.state == 'idle' then

		if drip.typ == 'main' then   
	
			if U.PlayerCloserThan( e, soundDist ) then
			
				GetEntityPlayerVisibility( e )
				if Ent.plrvisible == 1 then 
				
					local pp = { x = g_PlayerPosX, y = g_PlayerPosY + 30, z = g_PlayerPosZ }
				
					if timeNow > drip.timer then
						PlaySound( e, 0 )
						SetSound( e, 0 )
						SetSoundVolume( getVolume( drip.pos, pp ) )
						drip.timer = timeNow + dripRate
					
						local el = checkForEchoPoints( drip.pos, drip.obj )
					
						for _, v in pairs( el ) do
							makeEcho( timeNow, v, pp, drip.pos )
						end
					end
				end
			end
		end
	
	elseif
	   drip.state == 'echo' then
		if timeNow > drip.timer then
			PlaySound( e, 0 )
			SetSound( e, 0 )
			SetSoundVolume( getVolume( drip.pos, { x = g_PlayerPosX, y = g_PlayerPosY + 30, z = g_PlayerPosZ } ) - 15 )
			drip.state = 'idle'
		end
	end
	
	PromptLocal( e, drip.state .. "," .. Ent.plrvisible )
end