button

--- Button API for ComputerCraft.
-- @author direwolf20, refactored by Telinc1.

local monitor = peripheral.find("monitor")
monitor.setTextScale(1)
monitor.setTextColor(colors.white)
monitor.setBackgroundColor(colors.black)

local buttons = {}

--- Add a button to the button table.
-- @param name The name of the button (also used as its label).
-- @param callback The function to call on clicking the button.
-- @param x The X position of the button.
-- @param y The Y position of the button.
-- @param width The width of the button.
-- @param height The height of the button.
function addButton(name, callback, x, y, width, height)
    buttons[name] = {}
    buttons[name]["callback"] = callback
    buttons[name]["active"] = false
    buttons[name]["left"] = x
    buttons[name]["top"] = y
    buttons[name]["right"] = x + width
    buttons[name]["bottom"] = y + height
end

--- Remove a button from the button table.
-- @param name The name of the button to remove.
function removeButton(name)
    buttons[name] = nil
end

--- Remove all buttons from the table and clear the monitor.
function clearButtons()
    buttons = {}
    monitor.clear()
end

--- Draw a piece of button-styled text with the specified background color.
-- @param text The label of the button.
-- @param color The color of the button.
-- @param data The button's data, used for its positioning.
function draw(text, color, data)
    monitor.setBackgroundColor(color)

    local textX = math.floor((data["right"] - data["left"] - string.len(text)) / 2) + 1
    local textY = math.floor((data["top"] + data["bottom"]) / 2)

    for j = data["top"], data["bottom"] do
        monitor.setCursorPos(data["left"], j)

        if j == textY then
            for k = 0, data["right"] - data["left"] - string.len(text) + 1 do
                if k == textX then
                    monitor.write(text)
                else
                    monitor.write(" ")
                end
            end
        else
            for i = data["left"], data["right"] do
                monitor.write(" ")
            end
        end
    end

    monitor.setBackgroundColor(colors.black)
end

--- Draw all the buttons to the monitor.
function refresh()
    local currentColor

    for name, data in pairs(buttons) do
        if data["active"] == true then currentColor = colors.lime else currentColor = colors.red end
        draw(name, currentColor, data)
    end
end

--- Toggle a button's active state and refresh the screen.
-- @param name The button to toggle.
function toggle(name)
   button[name]["active"] = not buttons[name]["active"]
   refresh()
end

--- Flip a button's active state for 0.15 seconds.
-- @param name The button to flash.
function flash(name)
   toggle(name)
   sleep(0.15)
   toggle(name)
end

--- Check (x, y) for a button and execute its callback.
-- @param x The X coordinate of the point.
-- @param y The Y coordinate of the point.
function checkXY(x, y)
    for name, data in pairs(buttons) do
        if y >= data["top"] and y <= data["bottom"] then
            if x >= data["left"] and x <= data["right"] then
                data["callback"]()
                return true
            end
        end
    end

    return false
end

--- Draw a centered heading to the monitor.
-- @param text The heading to draw.
function heading(text)
   width, height = monitor.getSize()

   monitor.setCursorPos((width - string.len(text)) / 2 + 1, 1)
   monitor.write(text)
end

--- Draw a label to the monitor.
-- @param x The X position of the label.
-- @param y The Y position of the label.
-- @param text The label to draw.
function label(x, y, text)
   monitor.setCursorPos(x, y)
   monitor.write(text)
end