local NULL = function() end
local function checkColorTableValidation(C)
    if C then
        if type(C) == "table" then
            if #C == 3 or #C == 4 then
                for _, v in pairs(C) do
                    if type(v) ~= "number" or v<0 or v>1 then return false end
                end
            else
                return false
            end
        else
            return false
        end
    end
    return true
end

---@class BUTTON.button
---@field name string
---@field x number
---@field y number
---@field w number
---@field h number
---@field r number # Round corner
---
---@field borderWidth number
---@field borderJoin "bevel"|"miter"|"none"
---@field borderStyle "rough"|"smooth"
---
---@field font love.Font
---
---@field codeWhenPressed   function
---@field codeWhenReleased  function
---
---@field _hovering? boolean
---
---@field draw function
---@field update function
local button = {
    name = "NEW BUTTON",
    x = 0, y = 0, w = 1, h = 1, r = 0,

    backgroundColor = {0,0,0,0},
    hoverColor = {1,1,1,0.5},
    borderColor = {1,1,1},
    textColor = {1,1,1},

    font = love.graphics.newFont(15),

    borderWidth = 1,
    borderJoin = "none",
    borderStyle = "smooth",

    codeWhenPressed  = NULL,
    codeWhenReleased = NULL,

    _hovering = false
}; button.__index = button
function button:draw()
    love.graphics.setLineWidth(self.borderWidth)
    love.graphics.setLineStyle(self.borderStyle)
    love.graphics.setLineJoin(self.borderJoin)

    love.graphics.setColor(self.backgroundColor)
    love.graphics.rectangle('fill', self.x, self.y, self.w, self.h, self.r)

    if self._hovering then
        love.graphics.setColor(self.hoverColor)
        love.graphics.rectangle('fill', self.x, self.y, self.w, self.h, self.r)
    end

    love.graphics.setColor(self.textColor)
    love.graphics.setFont(self.font)
    love.graphics.printf(self.name, self.x, self.y + (self.h * 0.25), self.w, "center")

    love.graphics.setColor(self.borderColor)
    love.graphics.rectangle('line', self.x, self.y, self.w, self.h, self.r)
end
function button:isHovering(x,y)
    if
        x >= self.x and
        y >= self.y and
        x <= self.x + self.w and
        y <= self.y + self.h
    then
        self._hovering = true
    else
        self._hovering = false
    end
end
---@param touch? boolean @ If the button is touched, remember to pass true into touch param
function button:press(touch)
    if touch or self._hovering then
        self.codeWhenPressed()
    end
end
---@param touch? boolean @ If the button is touched, remember to pass true into touch param
function button:release(touch)
    if touch or self._hovering then
        self.codeWhenReleased()
    end
end


local BUTTON = {}

---@param D BUTTON.newData
---Validate the provided data, will be called by ``BUTTON.new`` and ``BUTTON.setDefaultOption``<br>
---***WARNING! THIS FUNCTION WILL RAISE EXCEPTION IF DATA IS INVALID!***
function BUTTON.checkDataValidation(D)
    assert(type(D.name) == "string", "[name] is missing or not valid")

    assert(type(D.x) == "number", "[x] must be a integer")
    assert(type(D.y) == "number", "[y] must be a integer")
    assert(type(D.w) == "number" and D.w > 0, "[w] must be a positive integer")
    assert(type(D.h) == "number" and D.h > 0, "[h] must be a positive integer")
    assert((type(D.r) == "number" and D.r >= 0 and D.r <= D.w * 0.5 and D.r <= D.h * 0.5) or D.r == nil, "[r] must be a positive integer and cannot larger than half of button's width and half of button's height")
    assert((type(D.borderWidth) == "number" and D.borderWidth > 0) or D.borderWidth == nil, "[borderWidth] must be a postive integer")
    assert(table.contains({"bevel", "miter", "none"}, D.borderJoin) or D.borderJoin == nil, "[borderJoin] must be 'bevel', 'miter' or 'none")
    assert(table.contains({"rough", "smooth"}, D.borderStyle) or D.borderStyle == nil, "[borderStyle] must be 'rough' or 'smooth'")
    assert((D.font and D.font.typeOf and D.font:typeOf("Font")) or D.font == nil, "[font] must be love.Font")

    assert(checkColorTableValidation(D.backgroundColor), "[backgroundColor] must be a table with r, g, b (, a) values, all of them must be integers between 0 and 1")
    assert(checkColorTableValidation(D.hoverColor), "[hoverColor] must be a table with r, g, b (, a) values, all of them must be integers between 0 and 1")
    assert(checkColorTableValidation(D.borderColor), "[borderColor] must be a table with r, g, b (, a) values, all of them must be integers between 0 and 1")
    assert(checkColorTableValidation(D.textColor), "[textColor] must be a table with r, g, b (, a) values, all of them must be integers between 0 and 1")

    assert(type(D.codeWhenPressed)  == "function" or D.codeWhenPressed  == nil, "[codeWhenPressed] must be a function or nil")
    assert(type(D.codeWhenReleased) == "function" or D.codeWhenReleased == nil, "[codeWhenReleased] must be a function or nil")
    assert(type(D.drawingButtonFunc)  == "function" or D.drawingButtonFunc  == nil, "[drawingButtonFunc] must be a function or nil")
end


---@class BUTTON.newData
---@field name? string # Name of the button, will be used to show
---@field x? number # Position of the button (x, y, w, h)
---@field y? number # Position of the button (x, y, w, h)
---@field w? number # Position of the button (x, y, w, h)
---@field h? number # Position of the button (x, y, w, h)
---@field r? number # Radius corner, cannot larger than half of button's width and half of button's height
---
---@field borderWidth? number|1 # Line width will be used to draw button
---@field borderJoin? "bevel"|"miter"|"none"
---@field borderStyle? "rough"|"smooth"
---
---@field font? love.Font
---
---@field backgroundColor? table<[r,g,b,a]>
---@field textColor? table<[r,g,b,a]>
---@field borderColor? table<[r,g,b,a]>
---@field hoverColor? table<[r,g,b,a]>
---
---@field codeWhenPressed? function| # Code will be execute when pressed
---@field codeWhenReleased? function| # Code will be execute when released
---@field drawingButtonFunc? function| # The function is used to draw text<br>You can override the default one if you feel the default text drawing function is not suitable for you

---@param D BUTTON.newData
---@return BUTTON.button
---Create a new button, provide you a table with 4 functions inside: draw and update, press and release<br>
---You need to put them into intended callbacks :)
function BUTTON.new(D)
    BUTTON.checkDataValidation(D)
    return setmetatable({
        name = D.name,
        x = D.x,
        y = D.y,
        w = D.w,
        h = D.h,
        r = D.r,

        borderWidth = D.borderWidth,
        borderJoin = D.borderJoin,
        borderStyle = D.borderStyle,

        backgroundColor = D.backgroundColor,
        hoverColor = D.hoverColor,
        textColor = D.textColor,
        borderColor = D.borderColor,

        codeWhenPressed   = D.codeWhenPressed,
        codeWhenReleased  = D.codeWhenReleased,
        drawingButtonFunc = D.drawingButtonFunc,
    }, button)
end

---@param D BUTTON.newData
function BUTTON.setDefaultOption(D)
    ---@diagnostic disable-next-line: param-type-mismatch
    BUTTON.checkDataValidation(setmetatable(D, button))
    for k, v in pairs(D) do
        if button[k] ~= nil then
            button[k] = v
        else
            error("There is no "..k.." parameter in BUTTON!")
        end
    end
end

return BUTTON