--Button api for computercraft by Siarko
--Usage:
--
-- FIRST SET MONITOR HANDLE BY
-- button.setMonitor(handle)
--
-- new button object creation:
--  myFancyButton = button.create([label])
-- Methods:
-- setText, setPos, setSize, setColor, setBlinkColor, setActive, onClick
-- return button object so they can be chained eg:
-- myButton = button.create("My button").setSize(5,5).setColor(colors.gray).onClick(function)
-- setText(string, resize-bool) - sets button label; if resize then auto changes size to fit label
-- setSize(int, int), setPos(int, int) - quite self explainatory ;)
-- setColor(color) - sets background color, parameter color - computercraft colors api
-- setBlinkColor(color) - sets background to be drawn while button click
-- setActive(bool) - is button active and can be clicked? inactive - gray background
-- onClick(function) - function called when button is clicked
-- onClickReturn(value) - "await" function returns value instead of executing callback,
--   returns nil if no button was clicked
-- setAlign("left" / "center" / "right") - aligns label in button accordingly;
--   if label doesn't fit, it will be cut to fit, min button width = 4

--Activate waiting for click:
-- button.await(b1, b2, b3, ...)
-- or button.await(buttonArray)
-- b1, b2, b3, - single button objects
-- buttonArray - table containing buttons eg:
-- arr = {b1, b2, b3}
-- "await" function draws supplied buttons and waits for click, if any button is clicked
-- fires callback function set in button by "onClick()" method
-- probably should be called in loop

-- If you want to do something in the background you have to run "button.await" in another thread
-- like parallel.waitForAny(background, buttonAwaitFunction)

local _locales = {
    mon = nil
}

--button class
function create(text)
    local this = {
        x = 1,
        y = 1,
        w = 0,
        h = 1,
        text = tostring(text) or "None",
        bgcol = colors.lime,
        blinkCol = colors.red,
        align = "c",
        active = true,
        callback = nil,
        ret = nil,
        textColor = colors.black
    }

    if text ~= nil then
        this.w = #tostring(text)
    end

    --setters, return this object
    function this.setText(text, resize)
        this.text = tostring(text)
        if resize and this.w < #this.text then
            this.w = #this.text
        end
        return this
    end

    function this.setTextColor(color)
        this.textColor = color
        return this
    end

    function this.setAlign(align)
        if align == "center" then
            this.align = "c"
        elseif align == "left" then
            this.align = "l"
        elseif align == "right" then
            this.align = "r"
        else
            print("Incorrect slign set! ")
            error()
        end
        return this
    end

    function this.setPos(x, y)
        this.x = x
        this.y = y
        return this
    end

    function this.setSize(w, h)
        this.w = w
        this.h = h
        return this
    end

    function this.setColor(color)
        this.bgcol = color
        return this
    end

    function this.setBlinkColor(color)
        this.blinkCol = color
        return this
    end

    function this.setActive(state)
        this.active = state
        return this
    end

    function this.wasClicked(x,y)
        if
            x >= this.x and
            x < this.x+this.w and
            y >= this.y and
            y < this.y+this.h and
            this.active
        then
            return true
        end
        return false
    end

    function this.onClick(callback)
        this.callback = callback
        return this
    end

    function this.onClickReturn(value)
        this.ret = value
        return this
    end

    function this.fireEvent()
        if this.callback ~= nil then
            this.callback()
        end
    end

    function this.drawWrapper(bgcol)
        if _locales.mon == nil then
            print("Monitor not set!")
            error()
        end
        local xpos = this.x+(this.w/2-#this.text/2)
        local t = this.text
        local bg = _locales.mon.getBackgroundColor()
        local tc = _locales.mon.getTextColor()
        if this.align == "l" then
            xpos = this.x
        end
        if this.align == "r" then
            xpos = this.x+this.w-#this.text
        end
        if #this.text > this.w then
            xpos = this.x
            t = string.sub(t,1,this.w-3)..".."..string.sub(t,-1)
        end
        _locales.mon.setTextColor(this.textColor)
        local f = string.rep(" ", this.w)
        if this.active then
            _locales.mon.setBackgroundColor(bgcol)
        else
            _locales.mon.setBackgroundColor(colors.gray)
        end
        for i = 1, this.h do
            _locales.mon.setCursorPos(this.x, this.y+(i-1))
            _locales.mon.write(f)
        end
        _locales.mon.setCursorPos(xpos,this.y+this.h/2)
        _locales.mon.write(t)
        _locales.mon.setBackgroundColor(bg)
        _locales.mon.setTextColor(tc)
    end

    function this.draw()
        this.drawWrapper(this.bgcol)
    end

    function this.blink()
        this.drawWrapper(this.blinkCol)
        sleep(0.2)
        this.draw()
    end

    return this
end

--set Monitor handle to draw on
function setMonitor(mon)
    _locales.mon = mon
    --MON = mon
end

function clearMon()
    _locales.mon.clear()
end

local function isTable(element)
    return type(element) == "table"
end

local function isButton(element)
    if isTable(element) and element.text ~= nil then
        return true
    end
    return false
end

local function mergeTables(tab1, tab2)
    for i in pairs(tab2) do
        tab1[#tab1+1] = tab2[i]
    end
end

--manage button checks
function await(...)
    array = {}
    for i in pairs(arg) do
        if i ~= "n" then
            if isTable(arg[i]) and not isButton(arg[i]) then --table of buttons
                mergeTables(array, arg[i])
            else --single button
                array[#array+1] = arg[i]
            end
        end
    end

    for i in pairs(array) do
            array[i].draw()
    end
    e, s, x, y = os.pullEvent("monitor_touch")
    for i in pairs(array) do
        if array[i].wasClicked(x,y) then
            array[i].blink()
            if array[i].ret ~= nil then
                return array[i].ret
            end
            array[i].fireEvent()
        end
    end
end