local util = {}

function util.merge2(t1, t2)
    for k, v in pairs(t2) do
        if (type(v) == "table") and (type(t1[k] or false) == "table") then
            merge(t1[k], t2[k])
        else
            t1[k] = v
        end
    end
    return t1
end

function util.merge(t1, ...)
    for _, t2 in ipairs({...}) do
        t1 = util.merge2(t1, t2)
    end
    return t1
end

function util.lerp(a, b, t)
    return a + (b - a) * t
end

function util.lerpAngle(a, b, k)
    local pi = math.pi
    if (math.abs(a - b) > pi) then
        if (b > a) then
            a = a + pi * 2
        else
            b = b + pi * 2
        end
    end
    local value = (a + ((b - a) * k))
    local rangeZero = pi * 2
    if (value >= 0 and value <= pi * 2) then
        return value
    end
    return (value % rangeZero)
end

function util.rotateVector(x, y, r)
    local a = math.atan2(y, x)
    local d = math.sqrt(x * x + y * y)
    a = a + r
    return d * math.cos(a), d * math.sin(a)
end

function util.foreachi(t, f)
    for i = 1, #t do f(t[i], i) end
end

function util.foreachirev(t, f)
    for i = #t, 1, -1 do f(t[i], i) end
end

function util.foreach(t, f)
    for k, v in pairs(t) do f(v, k) end
end

function util.withShader(shader, f)
    local _shader = lovr.graphics.getShader()
    lovr.graphics.setShader(shader)
    f()
    lovr.graphics.setShader(_shader)
end

return util