"""Control panel drawn straight onto the output canvas: click a layer to toggle it, drag its sliders."""
import cv2

BG = (26, 24, 22)
TRACK = (52, 48, 46)
FG = (228, 228, 228)
DIM = (125, 125, 125)
ACCENT = (255, 176, 64)
FONT = cv2.FONT_HERSHEY_SIMPLEX


class Panel:
    WIDTH = 260

    def __init__(self, layers):
        self.layers = layers
        self.hits = []  # (x0, y0, x1, y1, target, bar_x0, bar_x1), rebuilt on every draw
        self.drag = None

    def draw(self, canvas, x0, status):
        h = canvas.shape[0]
        canvas[:, x0:] = BG
        self.hits = []
        x, right = x0 + 14, x0 + self.WIDTH - 14
        cv2.putText(canvas, "MOTIONLAB", (x, 26), FONT, 0.55, FG, 1, cv2.LINE_AA)
        cv2.putText(canvas, status, (x + 124, 26), FONT, 0.4, DIM, 1, cv2.LINE_AA)

        y = 44
        for layer in self.layers:
            on = layer.enabled
            cv2.rectangle(canvas, (x, y), (x + 12, y + 12), ACCENT if on else DIM, -1 if on else 1)
            cv2.putText(canvas, layer.name, (x + 22, y + 11), FONT, 0.48, FG if on else DIM, 1, cv2.LINE_AA)
            self.hits.append((x0, y - 5, x0 + self.WIDTH, y + 17, layer, 0, 0))
            y += 22
            if not on:
                continue
            bar = x + 100
            for name, p in layer.params.items():
                cv2.putText(canvas, name, (x + 4, y + 8), FONT, 0.36, DIM, 1, cv2.LINE_AA)
                cv2.rectangle(canvas, (bar, y), (right, y + 8), TRACK, -1)
                cv2.rectangle(canvas, (bar, y), (bar + int((right - bar) * p.norm), y + 8), ACCENT, -1)
                self.hits.append((bar - 8, y - 4, right + 8, y + 12, p, bar, right))
                y += 16
            y += 4

        cv2.putText(canvas, "[h] panel  [s] shot  [r] rec  [q] quit", (x, h - 12), FONT, 0.36, DIM, 1, cv2.LINE_AA)

    def on_mouse(self, event, mx, my, flags, _):
        if event == cv2.EVENT_LBUTTONDOWN:
            for x0, y0, x1, y1, target, bar_x0, bar_x1 in self.hits:
                if x0 <= mx < x1 and y0 <= my < y1:
                    if bar_x1:
                        self.drag = (target, bar_x0, bar_x1)
                    else:
                        target.enabled = not target.enabled
                    break
        elif event == cv2.EVENT_LBUTTONUP:
            self.drag = None
        if self.drag and event in (cv2.EVENT_LBUTTONDOWN, cv2.EVENT_MOUSEMOVE):
            param, bar_x0, bar_x1 = self.drag
            param.norm = (mx - bar_x0) / (bar_x1 - bar_x0)