"""Launcher icon studies: the Asheron's Call ring motif, made acdream's own."""
import numpy as np
from PIL import Image, ImageFilter, ImageChops

import render, ring, compose, smooth


def portal_swirl(size=1024, arms=2.0, twist=2.9,
                 core=(0.92, 0.95, 1.00), mid=(0.36, 0.52, 0.95),
                 outer=(0.30, 0.14, 0.52)):
    """Procedural log-spiral vortex -- AC's other signature image."""
    y, x = np.mgrid[0:size, 0:size].astype(np.float32)
    x = (x / (size - 1)) * 2 - 1
    y = (y / (size - 1)) * 2 - 1
    r = np.sqrt(x * x + y * y)
    th = np.arctan2(y, x)

    safe = np.clip(r, 1e-3, None)
    spiral = np.sin(arms * th + twist * np.log(safe) * 3.2)
    spiral = (spiral * 0.5 + 0.5) ** 1.15

    # gentler falloff + a much wider core, so the vortex fills the ring rather
    # than sitting in the middle of it as a speck
    falloff = np.clip(1.0 - r / 1.05, 0, 1) ** 0.85
    corebloom = np.exp(-(r ** 2) / 0.075)

    t = np.clip(r / 0.9, 0, 1)[..., None]
    ramp = (np.array(mid, dtype=np.float32)[None, None, :] * (1 - t)
            + np.array(outer, dtype=np.float32)[None, None, :] * t)
    rgb = ramp * (0.42 + 1.25 * spiral)[..., None] * falloff[..., None]
    rgb = rgb + np.array(core, dtype=np.float32)[None, None, :] * corebloom[..., None]
    a = np.clip(falloff * (0.55 + 0.95 * spiral) + corebloom, 0, 1)

    img = np.concatenate([np.clip(rgb, 0, 1), a[..., None]], axis=2)
    return Image.fromarray((img * 255).astype(np.uint8), "RGBA")


def inner_shadow(subject_alpha, size, blur=22, opacity=0.6, dy=10):
    """Soft shadow cast by the ring onto whatever sits inside it."""
    s = subject_alpha.filter(ImageFilter.GaussianBlur(blur))
    s = ImageChops.offset(s, 0, dy)
    s = s.point(lambda v: int(v * opacity))
    sh = Image.new("RGBA", (size, size), (0, 0, 0, 0))
    sh.putalpha(s)
    return sh


def render_ring(size=1024, matcap=None, gap_deg=26.0, el=0.0, exposure=1.0,
                gap_center_deg=90.0, R=1.0, r=0.135):
    mc = {"RING": matcap if matcap is not None else ring.chrome_matcap(768)}
    rp, rn, ruv, rt = ring.forged_ring(R=R, r=r, gap_deg=gap_deg,
                                       gap_center_deg=gap_center_deg)
    mesh = (rp, rn, ruv, rt, ["RING"] * len(rt))
    return render.render(mesh, {}, size=size, ss=3, az=270, el=el, fov=30,
                         fit=1.0, matcaps=mc, exposure=exposure)


def render_hook(size=1024, matcap=None, exposure=1.0, scale=0.60):
    mc = {"RING": matcap if matcap is not None else ring.chrome_matcap(768)}
    gp, gn, guv, gt = ring.hook_glyph(scale=scale)
    mesh = (gp, gn, guv, gt, ["RING"] * len(gt))
    return render.render(mesh, {}, size=size, ss=3, az=270, el=0, fov=30,
                         fit=1.0, matcaps=mc, exposure=exposure)


def place(canvas, sub, occupancy, offset=(0.0, 0.0)):
    """Scale `sub` to `occupancy` of the canvas and paste it centred + offset."""
    size = canvas.size[0]
    bbox = sub.split()[3].getbbox()
    s = sub.crop(bbox)
    k = (size * occupancy) / max(s.width, s.height)
    s = s.resize((max(1, int(s.width * k)), max(1, int(s.height * k))), Image.LANCZOS)
    layer = Image.new("RGBA", canvas.size, (0, 0, 0, 0))
    layer.paste(s, (int((size - s.width) / 2 + size * offset[0]),
                    int((size - s.height) / 2 + size * offset[1])), s)
    return Image.alpha_composite(canvas, layer), layer