-- patterning
-- norns study 2

engine.name = "PolyPerc"

function init()
    engine.release(3)
    notes = {}
    selected = {}
    -- build a scale, clear selected notes
    for m = 1, 5 do
        notes[m] = {}
        selected[m] = {}
        for n = 1, 5 do
            notes[m][n] = 55 * 2 ^ ((m * 12 + n * 2) / 12)
            selected[m][n] = 0
        end
    end
    light = 0
    number = 3
    release_amount = 3
    min_display_release = 1
    max_display_release = 10
    min_release_length = 0.1
    max_release_length = 4.0
end

function redraw()
    screen.clear()
    for m = 1, 5 do
        for n = 1, 5 do
            screen.rect(0.5 + m * 9, 0.5 + n * 9, 6, 6)
            l = 2
            if selected[m][n] == 1 then
                l = l + 3 + light
            end
            screen.level(l)
            screen.stroke()
        end
    end
    screen.move(10, 60)
    screen.text(number)

    screen.move(20, 60)
    screen.text(release_amount)
    screen.update()
end

function remap(value, from1, to1, from2, to2)
    return (value - from1) / (to1 - from1) * (to2 - from2) + from2
end

function key(n, z)
    if n == 2 and z == 1 then
        -- clear selected
        for x = 1, 5 do
            for y = 1, 5 do
                selected[x][y] = 0
            end
        end
        -- choose new random notes
        for i = 1, number do
            selected[math.random(5)][math.random(5)] = 1
        end
    elseif n == 3 then
        -- find notes to play
        if z == 1 then
            for x = 1, 5 do
                for y = 1, 5 do
                    if selected[x][y] == 1 then
                        mapped_release =
                            remap(
                            release_amount,
                            min_display_release,
                            max_display_release,
                            min_release_length,
                            max_release_length
                        )
                        engine.release(mapped_release)
                        engine.hz(notes[x][y])
                    end
                end
            end
            light = 7
        else
            light = 0
        end
    end
    redraw()
end

function enc(n, d)
    if n == 2 then
        release_amount = math.min(max_display_release, (math.max(release_amount + d, min_display_release)))
    elseif n == 3 then
        -- clamp number of notes from 1 to 4
        number = math.min(4, (math.max(number + d, 1)))
    end
    redraw()
end