-- GLON: Garry's Mod Lua Object Notation
-- A extension of LON: Lua Object Notation
-- Made entirely by Deco Da Man
-- Types:
    -- 2: table
    -- 3: array
    -- 4: fasle boolean
    -- 5: true boolean
    -- 6: number (NOT COMPRESSED, it isn't worth it)
    -- 7: string
    ---- non-LON types start here!
    -- 8: Vector (NOT COMPRESSED, it isn't worth it)
    -- 9: Angle (NOT COMPRESSED, it isn't worth it)
    -- 10: Entity (Can do players, vehicles, npcs, weapons and any other type of entity (-1 for null entity))
    -- 11: Player (By UserID)
    -- 12: CEffectData
    -- 13: ConVar (Not ClientConVar)
    -- 15: Color
    -- 254: The number equal to -math.huge (tostring(math.huge) == "-1.#INF")
    -- 254: The number equal to math.huge (tostring(math.huge) == "1.#INF")
    -- 255: reference (Sends the ID of the table to use (for "local t = {} t.a=t"))
local pairs = pairs
local type = type
local string = string
local math = math
local tostring = tostring
local IsValid = IsValid
local error = error
local print = print
local setmetatable = setmetatable
local Vector = Vector
local Angle = Angle
local Entity = Entity
local EffectData = EffectData
local GetConVar = GetConVar
local tonumber = tonumber
local player = player
local IsValid = IsValid
module("glon")
local encode_types
local decode_types
local function InDataEscape(s)
    s = string.gsub(s, "([\1\2])", "\2%1")
    s = string.gsub(s, "%z", "\2\3")
    s = string.gsub(s, "\"", "\4") -- escape the " character to simplify client commands
    return s
end
encode_types = {
    ["nil"] = {nil, function()
        return "", nil
    end},
    table = {2, function(o, rtabs)
        for k,v in pairs(rtabs) do
            if v == o then
                return tostring(k).."\1", 255
            end
        end
        rtabs[#rtabs+1] = o
        local is_array = true
        local i = 0
        for k,v in pairs(o) do
            i = i + 1
            if k ~= i or type(k) ~= "number" or math.floor(k) ~= k then
                is_array = false
            break end
        end
        local s = ""
        for k,v in pairs(o) do

            if ( !encode_types[type(v)] ) then continue end

            if not is_array then
                s = s..Write(k, rtabs)
            end
            s = s..Write(v, rtabs)
        end
        return s.."\1", is_array and 3
    end},
    boolean = {4, function(o)
        return "", o and 5
    end},
    number = {6, function(o)
        o = o == 0 and "" or o
        return o == ((o == math.huge or o == -math.huge) and "") or tostring(o).."\1", (o == math.huge and 254) or (o == -math.huge and 253)
    end},
    string = {7, function(o)
        return InDataEscape(o).."\1"
    end},
    -- non-LON types start here!
    Vector = {8, function(o)
        return o.x.."\1"..o.y.."\1"..o.z.."\1"
    end},
    Angle = {9, function(o)
        return o.p.."\1"..o.y.."\1"..o.r.."\1"
    end},
    Entity = {10, function(o)
        return (IsValid(o) and o:EntIndex() or -1).."\1"
    end},
    NPC = {10, function(o)
        return (IsValid(o) and o:EntIndex() or -1).."\1"
    end},
    Weapon = {10, function(o)
        return (IsValid(o) and o:EntIndex() or -1).."\1"
    end},
    Player = {11, function(o)
        return o:EntIndex().."\1"
    end},
    CEffectData = {12, function(o, rtabs)
        local t = {}
        if o:GetAngles() ~= Angle(0,0,0) then
            t.a = o:GetAngles()
        end
        if o:GetAttachment() ~= 0 then
            t.h = o:GetAttachment()
        end
        if o:GetEntity():IsValid() then
            t.e = o:GetEntity()
        end
        if o:GetMagnitude() ~= 0 then
            t.m = o:GetMagnitude()
        end
        if o:GetNormal() ~= Vector(0,0,0) then
            t.n = o:GetNormal()
        end
        if o:GetOrigin() ~= Vector(0,0,0) then
            t.o = o:GetOrigin()
        end
        if o:GetRadius() ~= 0 then
            t.r = o:GetRadius()
        end
        if o:GetScale() ~= 0 then
            t.c = o:GetScale()
        end
        if o:GetStart() ~= 0 then
            t.s = o:GetStart()
        end
        if o:GetSurfaceProp() ~= 0 then
            t.p = o:GetSurfaceProp()
        end
        return encode_types.table[2](t, rtabs)
    end},
    ConVar = {13, function(o)
        return InDataEscape(o:GetName()).."\1"
    end},
    PhysObj = {14, function(o)
        local parent, obj, id = o:GetEntity()
        for i = 1, parent:GetPhysicsObjectCount() do
            obj = parent:GetPhysicsObjectNum()
            if obj == o then
                id = i
            break end
        end
        return parent:EntIndex().."\1"..id.."\1"
    end},
    Color = {15, function(o)
        return o.r.."\1"..o.g.."\1"..o.b.."\1"..o.a.."\1"
    end},
}
function Write(data, rtabs)
    local t = encode_types[type(data)]
    if t then
        local data, id_override = t[2](data, rtabs)
        local char = id_override or t[1] or ""
        if char ~= "" then char = string.char(char) end
        return char..(data or "")
    else
        error(string.format("Tried to write unwriteable type: %s",
            type(data)))
    end
end
local CEffectDataTranslation = {
    a = "Angle",
    h = "Attachment",
    e = "Entity",
    m = "Magnitude",
    n = "Normal",
    o = "Origin",
    r = "Radius",
    c = "Scale",
    s = "Start",
    p = "SurfaceProp",
}
decode_types = {
    -- \2\6omg\1\6omgavalue\1\1
    [2  ] = function(reader, rtabs) -- table
        local t, c, pos = {}, reader:Next()
        rtabs[#rtabs+1] = t
        local stage = false
        local key
        while true do
            c, pos = reader:Peek()
            if c == "\1" then
                if stage then
                    error(string.format("Expected value to match key at %s! (Got EO Table)",
                        pos))
                else
                    reader:Next()
                    return t
                end
            else
                if stage then
                    t[key] = Read(reader, rtabs)
                else
                    key = Read(reader, rtabs)
                end
                stage = not stage
            end
        end
    end,
    [3  ] = function(reader, rtabs) -- array
        local t, i, c, pos = {}, 1, reader:Next()
        rtabs[#rtabs+1] = t
        while true do
            c, pos = reader:Peek()
            if c == "\1" then
                reader:Next()
                return t
            else
                t[i] = Read(reader, rtabs)
                i = i+1
            end
        end
    end,
    [4  ] = function(reader) -- false boolean
        reader:Next()
        return false
    end,
    [5  ] = function(reader) -- true boolean
        reader:Next()
        return true
    end,
    [6  ] = function(reader) -- number
        local s, c, pos, e = "", reader:Next()
        while true do
            c = reader:Next()
            if not c then
                error(string.format("Expected \1 to end number at %s! (Got EOF!)",
                    pos))
            elseif c == "\1" then
                break
            else
                s = s..c
            end
        end
        if s == "" then s = "0" end
        local n = tonumber(s)
        if not n then
            error(string.format("Invalid number at %s! (%q)",
                pos, s))
        end
        return n
    end,
    [7  ] = function(reader) -- string
        local s, c, pos, e = "", reader:Next()
        while true do
            c = reader:Next()
            if not c then
                error(string.format("Expected unescaped \1 to end string at position %s! (Got EOF)",
                    pos))
            elseif e then
                if c == "\3" then
                    s = s.."\0"
                else
                    s = s..c
                end
                e = false
            elseif c == "\2" then
                e = true
            elseif c == "\1" then
                s = string.gsub(s, "\4", "\"") -- unescape quotes
                return s
            else
                s = s..c
            end
        end
    end,
    [8  ] = function(reader) -- Vector
        local x = decode_types[6](reader)
        reader:StepBack()
        local y = decode_types[6](reader)
        reader:StepBack()
        local z = decode_types[6](reader)
        return Vector(x, y, z)
    end,
    [9  ] = function(reader) -- Angle
        local p = decode_types[6](reader)
        reader:StepBack()
        local y = decode_types[6](reader)
        reader:StepBack()
        local r = decode_types[6](reader)
        return Angle(p, y, r)
    end,
    [10 ] = function(reader) -- Entity
        return Entity(decode_types[6](reader))
    end,
    [11 ] = function(reader) -- Player
        local num = decode_types[6](reader)
        return player.GetByID(num)
    end,
    [12 ] = function(reader, rtabs) -- CEffectData
        local t = decode_types[2](reader, rtabs)
        local d = EffectData()
        for k,v in pairs(t) do
            d["Set"..CEffectDataTranslation[k]](d, v)
        end
        return d
    end,
    [13 ] = function(reader) -- ConVar
        return GetConVar(decode_types[7](reader))
    end,
    [14 ] = function(reader) -- PhysicsObject

        local ent = Entity(decode_types[6](reader))
        local bone = decode_types[6](reader)

        if ( !IsValid( ent ) ) then return nil end;
        return ent:GetPhysicsObjectNum( bone )
    end,
    [15 ] = function(reader) -- Color
        local r = decode_types[6](reader)
        reader:StepBack()
        local g = decode_types[6](reader)
        reader:StepBack()
        local b = decode_types[6](reader)
        reader:StepBack()
        local a = decode_types[6](reader)
        return Color(r, g, b, a)
    end,
    [253] = function(reader) -- -math.huge
        reader:Next()
        return -math.huge
    end,
    [254] = function(reader) -- math.huge
        reader:Next()
        return math.huge
    end,
    [255] = function(reader, rtabs) -- Reference
        return rtabs[decode_types[6](reader) - 1]
    end,
}
function Read(reader, rtabs)
    local t, pos = reader:Peek()
    if not t then
        error(string.format("Expected type ID at %s! (Got EOF)",
            pos))
    else
        local dt = decode_types[string.byte(t)]
        if not dt then
            error(string.format("Unknown type ID, %s!",
                string.byte(t)))
        else
            return dt(reader, rtabs or {0})
        end
    end
end
local reader_meta = {}
reader_meta.__index = reader_meta
function reader_meta:Next()
    self.i = self.i+1
    self.c = string.sub(self.s, self.i, self.i)
    if self.c == "" then self.c = nil end
    self.p = string.sub(self.s, self.i+1, self.i+1)
    if self.p == "" then self.p = nil end
    return self.c, self.i
end
function reader_meta:StepBack()
    self.i = self.i-1
    self.c = string.sub(self.s, self.i, self.i)
    if self.c == "" then self.c = nil end
    self.p = string.sub(self.s, self.i+1, self.i+1)
    if self.p == "" then self.p = nil end
    return self.c, self.i
end
function reader_meta:Peek()
    return self.p, self.i+1
end
function decode(data)
    if type(data) == "nil" then
        return nil
    elseif type(data) ~= "string" then
        error(string.format("Expected string to decode! (Got type %s)",
            type(data)
        ))
    elseif data:len() == 0 then
        return nil
    end


    return Read(setmetatable({
        s = data,
        i = 0,
        c = string.sub(data, 0, 0),
        p = string.sub(data, 1, 1),
    }, reader_meta), {})
end
function encode(data)
    return Write(data, {0}) -- to use the first key, to prevent it from interfereing with \1s. You can have up to 254 unique tables (including arrays)
end