require 'point'

-- Clickable UI button
---@class Button
---@field position Point
---@field size Point
---@field prevPressed boolean
---@field lastPressed boolean
Button = {
    position = Point:new( 1, 1 ),
    size = Point:new( 1, 1 ),
    prevPressed = false,
    lastPressed = false
}

-- Factory function
---@param position Point | nil
---@param size Point | nil
---@param pressed function | nil
---@param held function | nil
---@param released function | nil
---@return Button
function Button:new( position, size, pressed, held, released )
    local button = {
        position = position or Button.position,
        size = size or Button.size,
        prevPressed = false,
        lastPressed = false,
        pressed = pressed or Button.pressed,
        held = held or Button.held,
        released = released or Button.released
    }

    setmetatable( button, { __index = self } )

    return button
end

-- Called when button just clicked
function Button:pressed() end
-- Called when button is held
---@param dt number
function Button:held( dt ) dt = dt end
-- Called when button is just unclicked
function Button:released() end

-- Drawing function
function Button:draw()
    local x, y = self.position:coords()
    local w, h = self.size:coords()
    love.graphics.rectangle( 'line', x, y, w, h )
end

-- Check if given point is in bounds of button
---@param point Point
---@return boolean
function Button:checkPoint( point )
    local px, py = point:coords()
    local sx, sy = self.position:coords()
    local ex, ey = self.position:coords()
    ex = ex + sx
    ey = ey + sy
    return px >= sx and px <= ex and py >= sy and py <= ey
end

-- Changing states and calls appropriate functions
---@param dt number
---@param point Point
function Button:update( dt, point, pressed )
    self.prevPressed = self.lastPressed
    self.lastPressed = pressed

    if self.lastPressed and not self.prevPressed then
        local inBounds = self:checkPoint( point )
        if inBounds then
            self:pressed()
        end
    elseif self.lastPressed and self.prevPressed then
        self:held( dt )
    elseif not self.lastPressed and self.prevPressed then
        self:released()
    end
end