GUI!!!

math.round = function(n)
    return math.floor(n + .5)
end

local function inheritsFrom(baseClass)
    local new_class = {}
    local class_mt = {__index = new_class}

    new_class.new = function()
        local newinst = {}
        setmetatable(newinst, class_mt)
        return newinst
    end

    if baseClass then
        setmetatable(new_class, {__index = baseClass})
    end

    return new_class
end

-------------------------------------------------------------
-------------------------------------------------------------
--                    GUI Server class                     --
-------------------------------------------------------------
-------------------------------------------------------------
local BUTTON_LEFT = 1;
local BUTTON_RIGHT = 2;
local BUTTON_W_UP = 3;
local BUTTON_W_DOWN = 4;
local BUTTON_W = 5;

local gui_event = {
    x = 0;
    y = 0;
    button = BUTTON_LEFT;
    key = 0;
}
gui_event.__index = gui_event

gui_event.new = function()
    local t = {}
    setmetatable(t, gui_event)

    return t
end

local gui_server = {
    children = nil;
    width = 100; -- %
    height = 100; -- %
    x = 0;
    y = 0;
    parent = nil;
    parentIndex = 1;
    hasBgColor = true;
    bgColor = colors.lightBlue;
    isParent = false;
}
gui_server.__index = gui_server

gui_server.new = function(x, y, w, h, c)
    local t = {
        x = x;
        y = y;
        width = w;
        height = h;
        isParent = true;
    }
    t.children = (c == nil or type(c) ~= "table") and {} or c;
    setmetatable(t, gui_server)

    return t
end

function gui_server:addChild(c)
    if self.isParent then
        c.parent = self
        c.parentIndex = #self.children + 1
        table.insert(self.children, c)
    end
end

function gui_server:removeChild(i)
    if self.isParent then
        table.remove(self.children, i)

        for l = i, #self.children do
            self.children[i]:setIndex(self.children[i].parentIndex - 1)
        end
    end
end

function gui_server:pxSize()
    if self.parent == nil then
        local w, h = term.getSize()

        return math.round(w / 100 * self.width), math.round(h / 100 * self.height)
    end

    local w, h = self.parent:pxSize()

    return math.round(w / 100 * self.width), math.round(h / 100 * self.height)
end

function gui_server:pxPosLocal()
    if self.parent == nil then
        local w, h = term.getSize()
        return math.round(w / 100 * self.x), math.round(h / 100 * self.y)
    end

    local w, h = self.parent:pxSize()

    return math.round(w / 100 * self.x), math.round(h / 100 * self.y)
end

function gui_server:pxPosGlobal()
    if self.parent == nil then
        local w, h = term.getSize()
        return math.round(w / 100 * self.x), math.round(h / 100 * self.y)
    end

    local w, h = self.parent:pxSize()
    local pX, pY = self.parent:pxPosGlobal()

    -- print("w, h = " .. w .. ", " .. h)

    return math.round(w / 100 * self.x) + pX, math.round(h / 100 * self.y) + pY
end

function gui_server:removeSelf()
    if self.parent ~= nil then
        self.parent:removeChild(self.parentIndex)
    end
end

function gui_server:onMouseEvent(ev)
    -- print("Pressed button " .. ev.button .. " at (" .. ev.x .. ", " .. ev.y .. ")")

    if self.isParent then
        for _, c in ipairs(self.children) do
            c:onMouseEvent(ev)
        end
    end
end

function gui_server:onKeyEvent(ev)
    -- print("Pressed key " .. ev.key)

    if self.isParent then
        for _, c in ipairs(self.children) do
            c:onKeyEvent(ev)
        end
    end
end

function gui_server:draw()
    if self.hasBgColor then
        term.setBackgroundColor(self.bgColor)
        local w, h = self:pxSize()
        local x, y = self:pxPosGlobal()

        for _x = 0, w do
            for _y = 0, h do
                term.setCursorPos(_x + x, _y + x)
                io.write(" ")
            end
        end
    end

    if self.isParent then
        for _, c in ipairs(self.children) do
            c:draw()
        end
    end
end

function gui_server:redraw()
    if self.parent == nil then
        -- Do the drawing
        self:draw()
        return
    end

    self.parent:draw()
end



-------------------------------------------------------------
-------------------------------------------------------------
--                    GUI Button class                     --
-------------------------------------------------------------
-------------------------------------------------------------
local gui_button = inheritsFrom(gui_server)

function gui_button:init(text, x, y, w, h)
    self.textColor = colors.black
    self.bgColor = colors.white
    self.text = text
    self.x = x
    self.y = y
    self.width = w
    self.height = h
    self.onClick = function(x, y) end
end

function gui_button:draw()
    term.setTextColor(self.textColor)

    if self.hasBgColor then
        term.setBackgroundColor(self.bgColor)
        local w, h = self:pxSize()
        local x, y = self:pxPosGlobal()

        -- print("x, y = " .. x .. ", " .. y)

        for _x = 0, w - 1 do
            for _y = 0, h - 1 do
                -- print("Drawing at (" .. _x + x .. ", " .. _y + y .. ")")
                term.setCursorPos(_x + x, _y + y)
                io.write(" ")
            end
        end
    end

    local pX, pY = self:pxPosGlobal()
    -- print(pX .. ", " .. pY)
    local w, h = self:pxSize()
    local cX, cY = math.floor(pX + w / 2) - self.text:len() / 2, math.floor(pY + h / 2)
    term.setCursorPos(cX, cY)
    io.write(self.text:sub(1, (self.text:len() > w - 1 and w - 1 or self.text:len())))
end

function gui_button:onMouseEvent(ev)
    local _x, _y = self:pxPosGlobal()
    local w, h = self:pxSize()

    if ev.x >= _x and ev.x < _x + w and ev.y >= _y and ev.y < _y + h then
        self.onClick(ev.x, ev.y)
    end
end



-------------------------------------------------------------
-------------------------------------------------------------
--                    GUI Textbox class                    --
-------------------------------------------------------------
-------------------------------------------------------------
local gui_textbox = inheritsFrom(gui_server)

function gui_textbox:init(text, x, y, w, m_ch)
    self.text = text
    self.textColor = colors.black
    self.bgColor = colors.white
    self.replaceChar = nil
    self.chars = {}

    for i = 1, text:len() do
        table.insert(self.chars, text:sub(i, i))
    end

    local _w, h = term.getSize()

    self.x = x
    self.y = y
    self.width = w or 30
    self.height = 100 / h

    local sW, sH = self:pxSize()

    while sH ~= 1 do
        self.height = self.height - 0.2
        sW, sH = self:pxSize()
    end

    self.m_ch = m_ch or false
    self.__onClick = function(x, y)
        self:edit()
    end
    self.onClick = function(x, y) end
end

function gui_textbox:draw()
    term.setTextColor(self.textColor)

    if self.hasBgColor then
        term.setBackgroundColor(self.bgColor)
        local w, h = self:pxSize()
        local x, y = self:pxPosGlobal()

        -- print("x, y = " .. x .. ", " .. y)

        for _x = 0, w - 1 do
            for _y = 0, h - 1 do
                -- print("Drawing at (" .. _x + x .. ", " .. _y + y .. ")")
                term.setCursorPos(_x + x, _y + y)
                io.write(" ")
            end
        end
    end

    local pX, pY = self:pxPosGlobal()
    -- print(pX .. ", " .. pY)
    local w, h = self:pxSize()
    local cX, cY = pX, math.floor(pY + h / 2)
    term.setCursorPos(cX, cY)

    local line = self.text
    local _line = line

    if self.replaceChar then
        line = ""

        for i = 1, _line:len() do
            line = line .. self.replaceChar:sub(1, 1)
        end
    end

    io.write(line:sub(1, (line:len() > w - 1 and w - 1 or line:len())))
end

function gui_textbox:edit()
    local pX, pY = self:pxPosGlobal()
    -- print(pX .. ", " .. pY)
    local w, h = self:pxSize()
    term.setCursorPos(pX, math.floor(pY + h / 2))
    term.setCursorBlink( true )

    local line = self.text
    local cursorX = line:len()
    local chars = {}

    for i = 1, self.text:len() do
        table.insert(chars, self.text:sub(i, i))
    end

    local function redraw(r_ch)
        term.setTextColor(self.textColor)
        term.setBackgroundColor(self.bgColor)
        term.setCursorPos(pX, math.floor(pY + h / 2))

        line = ""

        for _, c in ipairs(chars) do
            line = line .. c
        end

        local _line = line

        if self.replaceChar then
            line = ""

            for i = 1, _line:len() do
                line = line .. self.replaceChar:sub(1, 1)
            end
        end

        for i = 1, w do
            io.write(" ")
        end

        term.setCursorPos(pX, math.floor(pY + h / 2))

        local currentX = pX

        if line:len() >= w - 1 and cursorX >= w - 1 then
            io.write(line:sub(cursorX - (w - 2), cursorX))
            currentX = pX + cursorX - line:sub(1, cursorX - (w - 1)):len()
        elseif line:len() >= w - 1 and cursorX < w - 1 then
            io.write(line:sub(1, w - 1))
            currentX = pX + cursorX
        else
            io.write(line)
            currentX = pX + cursorX
        end

        line = _line

        term.setCursorPos(currentX, math.floor(pY + h / 2))
    end

    redraw(self.replaceChar)

    while true do
        local ev, key = os.pullEvent()

        if ev == "key" then
            if key == keys.left then
                if cursorX > 0 then
                    cursorX = cursorX - 1
                end
            elseif key == keys.right then
                if cursorX < line:len() then
                    cursorX = cursorX + 1
                end
            elseif key == keys.enter then
                break
            elseif key == keys.backspace then
                if cursorX > 0 then
                    table.remove(chars, cursorX)
                    cursorX = cursorX - 1
                end
            elseif key == keys.delete then
                if cursorX < line:len() then
                    table.remove(chars, cursorX + 1)
                end
            end
        elseif ev == "char" then
            table.insert(chars, cursorX + 1, key)
            cursorX = cursorX + 1
        end

        redraw()
    end

    term.setCursorBlink(false)
    self.text = line
end

function gui_textbox:setText(t)
    self.text = t

    for i = 1, t:len() do
        self.chars[i] = t:sub(i, i)
    end
end

function gui_textbox:onMouseEvent(ev)
    local _x, _y = self:pxPosGlobal()
    local w, h = self:pxSize()

    if ev.x >= _x and ev.x < _x + w and ev.y >= _y and ev.y < _y + h then
        self.__onClick(ev.x, ev.y)
        self.onClick(ev.x, ev.y)
    end
end

local x = gui_server.new(0, 0, 100, 100)

local button = gui_button.new()
button:init("Exit", 25, 45, 50, 15)
button.textColor = colors.black
button.onClick = function()
    term.setCursorPos(0, 0)
    term.setBackgroundColor(colors.black)
    term.setTextColor(colors.white)
    term.clear()
    print(os.version())
    error()
end

local tb = gui_textbox.new()
tb:init("Textbox", 25, 15, 50)

x:addChild(button)
x:addChild(tb)
x:redraw()

while true do
    local ev, p1, p2, p3, p4 = os.pullEvent()

    local gui_ev = gui_event.new()

    if ev == "mouse_click" then
        gui_ev.button = p1
        if p1 == 3 then
            gui_ev.button = BUTTON_W
        end
        gui_ev.x = p2
        gui_ev.y = p3
        x:onMouseEvent(gui_ev)
    elseif ev == "mouse_scroll" then
        gui_ev.button = p1 == 1 and BUTTON_W_DOWN or BUTTON_W_UP
        gui_ev.x = p2
        gui_ev.y = p3
        x:onMouseEvent(gui_ev)
    elseif ev == "key" then
        gui_ev.key = p1
        x:onKeyEvent(gui_ev)
    end

    x:redraw()
end