hook.Add("PlayerFootstep", "snow", function(ply, pos, foot, sound, volume, rf)
    if sound:find("grass") then
        ply:EmitSound(Format("player/footsteps/snow%s.wav", math.random(6)), 60, math.random(95,105))
        return true
    end
end)

if SERVER then return end
module  ( "ms" , package.seeall )

--snow_data = nil
snow_data = snow_data or {}


local LP


local replace = {
    ["METASTRUCT_2/GRASS"] = true,
    ["GM_CONSTRUCT/GRASS"] = true,
--[[    ["maps/metastruct_2/metastruct_2/road_6120_8680_-12944"] = true,
    ["maps/metastruct_2/metastruct_2/road_-3656_12928_-13216"] = true,
    ["maps/metastruct_2/metastruct_2/road_-6332_11456_-13184"] = true,
    ["CONCRETE/CONCRETEFLOOR001A"] = true,
    ["maps/metastruct_2/tile/tileroof004b_-13744_12784_-13200"] = true,
    ["maps/metastruct_2/tile/tileroof004a_-14224_11856_-13216"] = true,
    ["maps/metastruct_2/tile/tileroof004a_-14192_12176_-12784"] = true,
    ["maps/metastruct_2/metastruct_2/road_-13008_12656_-13104"] = true,




    ["maps/metastruct_2/tile/tileroof004a_6120_8680_-12944"] = true,
    ["maps/metastruct_2/tile/tileroof004b_-14192_12176_-12784"] = true,
    ["maps/metastruct_2/tile/tileroof004b_-9035_13056_-13188"] = true,
    ["maps/metastruct_2/metastruct_2/road_-9035_13056_-13188"] = true,
    ["maps/metastruct_2/tile/tileroof004a_-6332_11456_-13184"] = true,
    ["maps/metastruct_2/tile/tileroof004b_6120_8680_-12944"] = true,     ]]


}
local rt = { "roof", "grass", "ceiling" }

if table.Count(snow_data) == 0 then

    local max = 16000
    local grid_size = 768
    local range = max/grid_size

    local pos

    for x = -range, range do
        x = x * grid_size
        for y = -range, range do
            y = y * grid_size
            for z = -range, range do
                z = z * grid_size

                pos = Vector(x,y,z)
                local conents = util.PointContents( pos )

                if conents == CONTENTS_EMPTY or conents == CONTENTS_TESTFOGVOLUME then
                    local up = util.QuickTrace(pos, vector_up*max*2)
                    if up.HitTexture == "TOOLS/TOOLSSKYBOX" or up.HitTexture == "**empty**" then
                        table.insert(snow_data, pos)
--[[                        local down = util.QuickTrace(pos, (vector_up*-1)*max*2)
                        if down.Hit then
                            local t = down.HitTexture:lower()
                            for k,v in pairs(rt) do
                                if string.find(t, v) ~= nil then
                                    replace[t] = true
                                end
                            end
                        end ]]
                    end
                end
            end
        end
    end
end

local function FastLength(point)
    return point.x*point.x+point.y*point.y+point.z*point.z
end

draw_these = {}

local emitter = ParticleEmitter(EyePos(), false)

local snow_explode = CreateClientConVar("snow_explode", "0", true, false)

local function SnowCallback(p, hitpos)
    if snow_explode:GetBool() then
        local efdata = EffectData() --Grab base EffectData table
        efdata:SetOrigin(hitpos) --Sets the origin of it to the hitpos of the particle
        efdata:SetStart(hitpos)
        efdata:SetScale(0.2)
        util.Effect("Explosion", efdata) --Create the effect
    end
    p:SetDieTime(0)
end

hook.Add("Think", "snow", function()
    for _, point in pairs(draw_these) do
        if math.random() < 0.95 then continue end
        local particle = emitter:Add("particle/snow", point)
        if (particle) then
            particle:SetVelocity(VectorRand()*100*Vector(1,1,0))
            particle:SetAngles(Angle(math.random(360), math.random(360), math.random(360)))
            particle:SetLifeTime(0)
            particle:SetDieTime(10)
            particle:SetStartAlpha(255)
            particle:SetEndAlpha(0)
            particle:SetStartSize(0)
            particle:SetEndSize(5)
            particle:SetGravity(Vector(0,0,math.Rand(-30, -200)))
            particle:SetCollide(true)
            particle:SetCollideCallback(SnowCallback)
        end
    end
end)

local function CreateSnowLoop(t)
    local iterations = math.min(math.ceil(#snow_data/(1/t)), #snow_data)
    local lastkey = 1
    local lastpos = nil
    local len = 3000^2
    local movelen = 100^2
    local LastLoop = -1
    timer.Create("hide_points", t, 0, function()
        if not IsValid(LP) then
            LP = LocalPlayer()
            if not IsValid(LP) then return end
        end
        local EP = LP:EyePos()+LP:GetVelocity()
        --[[local d = SysTime()-LastLoop
        if LastLoop ~= -1 and d > t+0.1 then
            local nt = t+0.05
            CreateSnowLoop(nt)
            return
        elseif t >= 0.1 and d <= t+0.01 then
            local nt = t-0.05
            CreateSnowLoop(nt)
            return
        end]]
        if lastpos == nil or FastLength(lastpos-EP) > movelen then
            local c = #snow_data
            local r = math.min(iterations, c)
            local completed = false
            for i=1,r do
                local key = lastkey+1
                if key > c then
                    completed = true
                    lastkey = 1
                    break
                end
                local point = snow_data[key]
                local dc = FastLength(point - EP) < len
                if dc and draw_these[key] == nil then
                    draw_these[key] = point
                elseif not dc and draw_these[key] ~= nil then
                    draw_these[key] = nil
                end
                lastkey = key
            end
            if completed then lastpos = EP end
        end
    end)
end
CreateSnowLoop(0.1)

do
materials = materials or {} local self = materials


materials.Replaced = {}

function materials.ReplaceTexture(path, to)
    check(path, "string")
    check(to, "string", "ITexture", "Material")

    path = path:lower()

    local mat = Material(path)

    if not mat:IsError() then

        local typ = type(to)
        local tex

        if typ == "string" then
            tex = Material(to):GetMaterialTexture("$basetexture")
        elseif typ == "ITexture" then
            tex = to
        elseif typ == "Material" then
            tex = to:GetMaterialTexture("$basetexture")
        else return false end

        self.Replaced[path] = self.Replaced[path] or {}

        self.Replaced[path].OldTexture = self.Replaced[path].OldTexture or mat:GetMaterialTexture("$basetexture")
        self.Replaced[path].NewTexture = tex

        mat:SetMaterialTexture("$basetexture",tex)

        return true
    end

    return false
end


function materials.SetColor(path, color)
    check(path, "string")
    check(color, "Vector")

    path = path:lower()

    local mat = Material(path)

    if not mat:IsError() then
        self.Replaced[path] = self.Replaced[path] or {}
        self.Replaced[path].OldColor = self.Replaced[path].OldColor or mat:GetMaterialVector("$color")
        self.Replaced[path].NewColor = color

        mat:SetMaterialVector("$color", color)

        return true
    end

    return false
end


function materials.RestoreAll()
    for name, tbl in pairs(self.Replaced) do
        if
            !pcall(function()
                if tbl.OldTexture then
                    materials.ReplaceTexture(name, tbl.OldTexture)
                end

                if tbl.OldColor then
                    materials.SetColor(name, tbl.OldColor)
                end
            end)
        then
            print("Failed to restore: " .. tostring(name))
        end
    end
end
hook.Add('ShutDown','MatRestorer',materials.RestoreAll)

-- Material Extensions / SkyBox modder
local sky =
{
    ["up"]=true,
    ["dn"]=true,
    ["lf"]=true,
    ["rt"]=true,
    ["ft"]=true,
    ["bk"]=true,
}

local sky_name = GetConVarString("sv_skyname")

for side, path in pairs(sky) do
    path = "skybox/" .. sky_name .. side
    materials.ReplaceTexture(path, "Decals/decal_paintsplatterpink001")
    --materials.SetColor(path, Vector(1.4, 1, 1)*3)
end

end

for k,v in pairs(replace) do
    materials.ReplaceTexture(k, "NATURE/SNOWFLOOR001A")
end