"""python3 -m unittest scripts/test_loop_window.py   (numpy, torch and kimodo; no model weights)"""
import math
import pathlib
import sys
import unittest

import numpy as np

sys.path.insert(0, str(pathlib.Path(__file__).resolve().parent))
from loop_window import loop_window, loop_windows  # noqa: E402
from types import SimpleNamespace  # noqa: E402

FPS = 30


def turn(points, angle):
    """Rotate points [..., 3] about Y by angle, so that +Z turns toward +X (Kimodo's heading: 0 faces +Z)."""
    x, z = points[..., 0], points[..., 2]
    out = points.copy()
    out[..., 0] = x * math.cos(angle) + z * math.sin(angle)
    out[..., 2] = -x * math.sin(angle) + z * math.cos(angle)
    return out


def stride(frames=240, period=37, start=40, end=200):
    """A stride cycle between two different rests. Hips travels; every other joint swings."""
    rng = np.random.default_rng(3)
    rest_a, rest_b = rng.normal(size=(2, 6, 3)) * 0.3
    phase, direction = rng.uniform(0, 6.28, 6), rng.normal(size=(6, 3))
    out = np.zeros((frames, 7, 3))
    for f in range(frames):
        weight = min(1.0, f / start, (frames - 1 - f) / (frames - 1 - end))
        rest = rest_a if f < frames // 2 else rest_b
        cycle = 0.2 * np.sin(2 * math.pi * f / period + phase)[:, None] * direction
        out[f, 1:] = weight * (rest_a + cycle) + (1 - weight) * rest
        out[f, 0] = (0.03 * f, 0.9, 0.0)  # Hips
        out[f, 1:] += out[f, 0]
    return out


def reference(joints, heading, fps, min_frames):
    """The cost written out frame by frame and joint by joint, to check the vectorised search against."""
    frames, count = joints.shape[0], joints.shape[1]
    pose = np.zeros((frames, count, 3))
    for f in range(frames):
        pose[f] = turn(joints[f] - joints[f, 0], -heading[f])
    velocity = np.zeros_like(pose)
    for f in range(frames):
        lo, hi = max(f - 1, 0), min(f + 1, frames - 1)
        velocity[f] = (pose[hi] - pose[lo]) / (hi - lo) * fps
    best = None
    for a in range(frames):
        for b in range(a + min_frames, frames):
            p = math.sqrt(sum(np.sum((pose[b, j] - pose[a, j]) ** 2) for j in range(count)) / count)
            v = math.sqrt(sum(np.sum((velocity[b, j] - velocity[a, j]) ** 2) for j in range(count)) / count)
            cost = p + 0.1 * v
            key = (cost, -(b - a), a)
            if best is None or key < best[0]:
                best = (key, a, b, p, v)
    return best[1:]


def wandering(frames=44, count=4, seed=0):
    """A smooth, unrepeating motion that turns as it goes, so the best window is unique and pose, velocity and
    heading each move it."""
    rng = np.random.default_rng(seed)
    time = np.arange(frames)
    joints = sum(rng.normal(size=(1, count, 3)) * 0.3 * np.sin(time[:, None, None] * rng.uniform(0.05, 0.5) + rng.uniform(0, 6.28))
                 for _ in range(4))
    heading = sum(0.4 * np.sin(time * rng.uniform(0.03, 0.2) + rng.uniform(0, 6.28)) for _ in range(2))
    return joints, heading


class LoopWindow(unittest.TestCase):
    def test_a_periodic_motion_between_rest_ramps(self):
        joints = stride()
        first, last, pose_cost, _ = loop_window(joints, np.zeros(240), FPS, 120)
        self.assertGreaterEqual(first, 40)
        self.assertLessEqual(last, 200)
        self.assertEqual((last - first) % 37, 0, (first, last))
        self.assertGreaterEqual(last - first, 120)
        self.assertLess(pose_cost, 1e-3)
        self.assertNotEqual((first, last), (0, 239), "the whole take is not the answer")

    def test_the_search_is_the_stated_cost(self):
        joints, heading = wandering()
        want_first, want_last, want_pose, want_velocity = reference(joints, heading, FPS, 22)
        got = loop_window(joints, heading, FPS, 22)
        self.assertEqual(got[:2], (want_first, want_last))
        self.assertAlmostEqual(got[2], want_pose, places=9)
        self.assertAlmostEqual(got[3], want_velocity, places=9)
        # The velocity term decides here: matching poses alone would pick another window.
        pose_only = min(
            ((np.sqrt(((turn(joints[b] - joints[b, 0], -heading[b]) - turn(joints[a] - joints[a, 0], -heading[a])) ** 2).sum(-1).mean()), a, b)
             for a in range(44) for b in range(a + 22, 44)))
        self.assertNotEqual(pose_only[1:], (want_first, want_last))

    def test_heading_is_normalised_away(self):
        joints, heading = wandering()
        upright = np.stack([turn(joints[f] - joints[f, :1], -heading[f]) + joints[f, :1] for f in range(44)])
        turned = np.stack([turn(upright[f] - upright[f, :1], heading[f]) + upright[f, :1] for f in range(44)])
        want = loop_window(upright, np.zeros(44), FPS, 22)
        got = loop_window(turned, heading, FPS, 22)
        self.assertEqual(got[:2], want[:2])
        self.assertAlmostEqual(got[2], want[2], places=9)
        self.assertNotEqual(loop_window(turned, np.zeros(44), FPS, 22)[:2], want[:2], "the turning would otherwise change the answer")

    def test_a_tie_goes_to_the_longer_window_then_the_earlier(self):
        cycle = np.array([[0, 0, 0], [0.5, 0.2, 0.1], [0.2, 0.7, 0.3], [0.4, 0.1, 0.9]], dtype=float)
        joints = np.stack([np.stack([np.zeros(3), cycle[f % 4]]) for f in range(30)])
        # Exact repeats every 4 frames: every a, b with b - a a multiple of 4 inside 1..28 costs zero.
        self.assertEqual(loop_window(joints, np.zeros(30), FPS, 15)[:2], (1, 25))
        still = np.zeros((30, 3, 3))
        self.assertEqual(loop_window(still, np.zeros(30), FPS, 15)[:2], (0, 29))

    def test_no_window_is_shorter_than_the_minimum(self):
        joints, heading = wandering(frames=31)
        for minimum in (5, 16, 25):
            first, last, _, _ = loop_window(joints, heading, FPS, minimum)
            self.assertGreaterEqual(last - first, minimum)
        self.assertEqual(loop_window(joints, heading, FPS, 30)[:2], (0, 30))

    def test_hips_is_the_joint_it_is_told(self):
        joints, heading = wandering()
        moved = joints[:, [2, 0, 1, 3]]
        self.assertEqual(loop_window(moved, heading, FPS, 22, hips=1), loop_window(joints, heading, FPS, 22, hips=0))

    def test_shapes_and_minimum_are_checked_without_echoing_them(self):
        joints, heading = wandering()
        for bad in ((joints, heading[:-1], 22), (joints, heading, 0), (joints, heading, 4321), (joints[..., :2], heading, 22)):
            with self.assertRaises(ValueError) as caught:
                loop_window(bad[0], bad[1], FPS, bad[2])
            self.assertNotIn("4321", str(caught.exception))


class StandInSkeleton:
    """What kimodo's heading and the worker read of a skeleton: the names and parents of the real one, its Hips index
    and the [right, left] hip joints (RightLeg, LeftLeg) that heading is taken from."""

    def __init__(self, names, parents):
        self.bone_order_names = [str(name) for name in names]
        self.bone_index = {name: index for index, name in enumerate(self.bone_order_names)}
        self.bone_parents = {name: (None if parent < 0 else self.bone_order_names[parent]) for name, parent in zip(self.bone_order_names, parents)}
        self.hip_joint_idx = [self.bone_index["RightLeg"], self.bone_index["LeftLeg"]]


class WorkerLoopWindowsTest(unittest.TestCase):
    """loop_windows on a real generated take (the somaskel77 joints of a live Vili take, 240 frames at 30 fps), with
    stand-ins for the model's two skeletons: the 77-joint output skeleton and the 30-joint one the model also carries."""

    @classmethod
    def setUpClass(cls):
        data = np.load(pathlib.Path(__file__).resolve().parent / "fixtures" / "take.npz")
        cls.joints = data["joints"]
        cls.model = SimpleNamespace(
            output_skeleton=StandInSkeleton(data["names77"], data["parents77"]),
            skeleton=StandInSkeleton(data["names30"], data["parents30"]),
            fps=FPS,
        )

    def window(self, joints):
        (answer,) = loop_windows({"posed_joints": [joints]}, self.model)
        return answer["first"], answer["last"]

    def test_the_real_take_gets_the_window_of_its_own_heading_in_the_output_skeleton(self):
        self.assertEqual(self.joints.shape, (240, 77, 3))
        self.assertEqual(self.model.output_skeleton.hip_joint_idx, [72, 67])
        self.assertEqual(self.model.skeleton.hip_joint_idx, [26, 22])
        self.assertEqual(self.window(self.joints), (35, 222))
        # The 30-joint skeleton's hip indices read the wrong joints of a 77-joint take and move the window.
        wrong = SimpleNamespace(output_skeleton=self.model.skeleton, fps=FPS)
        self.assertNotEqual(loop_windows({"posed_joints": [self.joints]}, wrong)[0]["first"], 35)

    def test_turning_the_body_about_its_hips_by_a_smooth_angle_leaves_the_window(self):
        turned = np.stack([
            turn(self.joints[f] - self.joints[f, 0], 0.8 * math.sin(0.05 * f)) + self.joints[f, 0] for f in range(len(self.joints))
        ]).astype(np.float32)
        self.assertEqual(self.window(turned), (35, 222))

    def test_each_sample_gets_its_own_window_with_its_costs(self):
        still = np.repeat(self.joints[:1], 240, axis=0)
        answers = loop_windows({"posed_joints": [self.joints, still]}, self.model)
        self.assertEqual([(a["first"], a["last"]) for a in answers], [(35, 222), (0, 239)])
        self.assertEqual(set(answers[0]), {"first", "last", "poseCost", "velocityCost"})
        self.assertAlmostEqual(answers[1]["poseCost"], 0.0, places=6)


if __name__ == "__main__":
    unittest.main()