-- Multibow internal "module" implementing Keybow LED-related functionality,
-- such as brightness control and "lighting up" a (multibow) keymap.

--[[
Copyright 2019 Harald Albrecht

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-- luacheck: globals mb

mb.MIN_BRIGHTNESS = mb.MIN_BRIGHTNESS or 0.1

-- Default LED brightness in the [0.1..1] range.
mb.brightness = 1

-- Sets the Keybow key LEDs maximum brightness, in the range [0.1..1] or
-- [10..100] (percent). The minim brightness is clamped on purpose to avoid
-- unlit LEDs. The lower clamp defaults to mb.MIN_BRIGHTNESS.
function mb.set_brightness(brightness)
    brightness = brightness > 1.0 and brightness / 100 or brightness
    if brightness < mb.MIN_BRIGHTNESS then brightness = mb.MIN_BRIGHTNESS end
    if brightness > 1 then brightness = 1 end
    mb.brightness = brightness
    mb.activate_leds()
end

-- Cycles through a list of brightness values, always taking the first
-- value and modifying the list by cycling it. Brightness values can be
-- either [0..1] or [0..100] (that is, percent)
function mb.cycle_brightness(brightnesses)
    local brightness = table.remove(brightnesses, 1)
    table.insert(brightnesses, brightness)
    mb.set_brightness(brightness)
    return brightnesses
end

-- Sets key LED to specific color, taking brightness into consideration.
-- The color is a triple (table) with the elements r, g, and b. Each color
-- component is in the range [0..1].
function mb.led(keyno, color)
    if color then
        local b = mb.brightness * 255
        keybow.set_pixel(keyno, color.r * b, color.g * b, color.b * b)
    else
        keybow.set_pixel(keyno, 0, 0, 0)
    end
  end

-- Restores Keybow LEDs according to current keymap and the permanent keymaps.
function mb.activate_leds()
    keybow.clear_lights()
    -- if a grab is in place then it takes absolute priority
    if mb.grab_keymap then
          mb.activate_keymap_leds(mb.grab_keymap)
    else
        -- first update LEDs for the current keymap...
        if mb.current_keymap ~= nil then
            mb.activate_keymap_leds(mb.current_keymap)
        end
        -- ...then update LEDs from permanent keymap(s), as this ensures that
        -- the permanent keymaps take precedence.
        for _, keymap in pairs(mb.keymaps) do
            if keymap.permanent then
            mb.activate_keymap_leds(keymap)
            end
        end
    end
end

-- Helper function that iterates over all keymap elements but skipping non-key
-- bindings.
function mb.activate_keymap_leds(keymap)
    for keyno, keydef in pairs(keymap) do
        -- Only iterates over keys, skipping any other keymap definitions.
        if type(keyno) == "number" and keydef.c then
            local color = type(keydef.c) == "function" and keydef.c() or keydef.c
            mb.led(keyno, color)
        end
    end
end