from __future__ import annotations

from functools import lru_cache
from pathlib import Path

import cv2
import numpy as np
from PIL import Image, ImageDraw, ImageFont

from canvas import PALETTE
from gestures import LABELS, Gesture, GestureState
from hand import HAND_CONNECTIONS, INDEX_TIP, Hand

_FONT_CANDIDATES = (
    "/System/Library/Fonts/Supplemental/Arial.ttf",
    "/System/Library/Fonts/Supplemental/Arial Unicode.ttf",
    "/System/Library/Fonts/HelveticaNeue.ttc",
    "/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf",
    "C:/Windows/Fonts/arial.ttf",
)

_ACCENT = {
    Gesture.DRAW: (90, 230, 90),
    Gesture.MOVE: (255, 190, 60),
    Gesture.GRAB: (60, 220, 255),
    Gesture.OPEN_PALM: (230, 230, 230),
    Gesture.ZOOM: (255, 110, 200),
    Gesture.OK: (120, 120, 255),
    Gesture.MIDDLE: (80, 80, 240),
    Gesture.PINKY: (200, 160, 255),
    Gesture.RING: (255, 210, 120),
    Gesture.NONE: (150, 150, 150),
}

HELP_LINES = (
    "GESTURES",
    "  One index finger - draw",
    "  Index and middle - move cursor",
    "  Fist (hold) - grab, move to rotate in 3D",
    "  Two fists - scale",
    "  Open palm - release",
    "  OK (hold) - clear canvas",
    "  Pinky (hold) - undo last stroke",
    "  Middle finger - :((",
    "  Two palms waving - quit",
    "",
    "KEYS",
    "  S save    C clear    U undo",
    "  1..6 color    [ ] size    R reset view",
    "  SPACE 2D/3D    K skeleton    D debug",
    "  H help    Q quit",
)

HELP_LINES_3D = (
    "GESTURES",
    "  One index finger - draw in depth",
    "  Index and middle - move cursor",
    "  Fist - rotate the drawing",
    "  Two fists - scale",
    "  Two ring fingers - depth colors",
    "  Open palm (hold) - reset view",
    "  OK (hold) - clear canvas",
    "  Pinky (hold) - undo last stroke",
    "  Middle finger - :((",
    "  Two palms waving - quit",
    "",
    "KEYS",
    "  S save    C clear    U undo",
    "  1..6 solid color    G depth gradient    [ ] size",
    "  R reset view    SPACE depth colors    K skeleton    D debug",
    "  H help    Q quit",
)


@lru_cache(maxsize=1)
def _font_path() -> str | None:
    """Find available font."""
    for p in _FONT_CANDIDATES:
        if Path(p).exists():
            return p
    return None


@lru_cache(maxsize=8)
def _font(size: int) -> ImageFont.FreeTypeFont | ImageFont.ImageFont:
    """Load font at size."""
    path = _font_path()
    if path is None:
        return ImageFont.load_default()
    return ImageFont.truetype(path, size)


@lru_cache(maxsize=256)
def _render_text(text: str, size: int, color: tuple[int, int, int]) -> tuple[np.ndarray, np.ndarray]:
    """Rasterize and cache text."""
    font = _font(size)
    dummy = ImageDraw.Draw(Image.new("L", (1, 1)))
    box = dummy.textbbox((0, 0), text, font=font)
    w = max(1, box[2] - box[0] + 4)
    h = max(1, box[3] - box[1] + 4)
    img = Image.new("L", (w, h), 0)
    ImageDraw.Draw(img).text((2 - box[0], 2 - box[1]), text, font=font, fill=255)
    alpha = np.array(img, dtype=np.float32) / 255.0
    rgb = np.zeros((h, w, 3), dtype=np.float32)
    rgb[:, :] = color
    return rgb, alpha


def put_text(
    frame: np.ndarray,
    text: str,
    org: tuple[int, int],
    size: int = 18,
    color: tuple[int, int, int] = (240, 240, 240),
) -> int:
    """Draw text string."""
    if not text:
        return size + 6
    rgb, alpha = _render_text(text, size, color)
    h, w = alpha.shape
    x, y = org
    fh, fw = frame.shape[:2]
    if x >= fw or y >= fh:
        return h
    x0, y0 = max(0, x), max(0, y)
    x1, y1 = min(fw, x + w), min(fh, y + h)
    if x1 <= x0 or y1 <= y0:
        return h
    sub_a = alpha[y0 - y : y1 - y, x0 - x : x1 - x][:, :, None]
    sub_c = rgb[y0 - y : y1 - y, x0 - x : x1 - x]
    roi = frame[y0:y1, x0:x1].astype(np.float32)
    frame[y0:y1, x0:x1] = (roi * (1 - sub_a) + sub_c * sub_a).astype(np.uint8)
    return h


def panel(frame: np.ndarray, x: int, y: int, w: int, h: int, alpha: float = 0.55) -> None:
    """Dark translucent backing."""
    fh, fw = frame.shape[:2]
    x0, y0 = max(0, x), max(0, y)
    x1, y1 = min(fw, x + w), min(fh, y + h)
    if x1 <= x0 or y1 <= y0:
        return
    roi = frame[y0:y1, x0:x1]
    dark = np.zeros_like(roi)
    cv2.addWeighted(dark, alpha, roi, 1 - alpha, 0, roi)


def draw_hand(frame: np.ndarray, hand: Hand, state: GestureState, kpt_conf: float = 0.3) -> None:
    """Draw hand skeleton."""
    kp = hand.keypoints
    ok = hand.scores >= kpt_conf
    color = _ACCENT.get(state.gesture, (150, 150, 150))
    for a, b in HAND_CONNECTIONS:
        if ok[a] and ok[b]:
            cv2.line(frame, tuple(kp[a].astype(int)), tuple(kp[b].astype(int)),
                     (60, 60, 60), 3, cv2.LINE_AA)
            cv2.line(frame, tuple(kp[a].astype(int)), tuple(kp[b].astype(int)),
                     color, 1, cv2.LINE_AA)
    for i in range(21):
        if ok[i]:
            cv2.circle(frame, tuple(kp[i].astype(int)), 3, color, -1, cv2.LINE_AA)
    if state.gesture == Gesture.DRAW:
        cv2.circle(frame, tuple(kp[INDEX_TIP].astype(int)), 9, (90, 230, 90), 2, cv2.LINE_AA)
    elif state.gesture == Gesture.GRAB:
        cv2.circle(frame, tuple(hand.center.astype(int)), 16, (60, 220, 255), 2, cv2.LINE_AA)


_POSE_LIMB = (255, 210, 90)
_POSE_FACE = (190, 240, 170)
_POSE_JOINT = (255, 255, 255)
_POSE_WEAK = (110, 90, 90)


def draw_pose(frame: np.ndarray, pose, threshold: float = 0.35,
              labels: bool = False) -> None:
    """Draw one body skeleton with its keypoints."""
    from pose import FACE, KEYPOINT_NAMES, SKELETON

    kp = pose.keypoints
    ok = pose.scores >= threshold
    # Scale the strokes with the frame so the skeleton stays readable when the
    # camera view is shrunk into a corner inset.
    k = max(frame.shape[1] / 1280.0, 0.35)
    thin = max(int(round(2 * k)), 1)
    halo = thin + max(int(round(3 * k)), 2)

    for a, b in SKELETON:
        pa, pb = tuple(kp[a].astype(int)), tuple(kp[b].astype(int))
        if ok[a] and ok[b]:
            color = _POSE_FACE if (a in FACE and b in FACE) else _POSE_LIMB
            cv2.line(frame, pa, pb, (25, 25, 30), halo, cv2.LINE_AA)
            cv2.line(frame, pa, pb, color, thin, cv2.LINE_AA)
        elif ok[a] or ok[b]:
            cv2.line(frame, pa, pb, _POSE_WEAK, max(thin - 1, 1), cv2.LINE_AA)

    for i in range(len(kp)):
        p = tuple(kp[i].astype(int))
        if not ok[i]:
            cv2.circle(frame, p, max(int(round(2 * k)), 1), _POSE_WEAK, -1, cv2.LINE_AA)
            continue
        radius = max(int(round((3 if i in FACE else 5) * k)), 2)
        cv2.circle(frame, p, radius + max(int(round(2 * k)), 1), (25, 25, 30), -1, cv2.LINE_AA)
        cv2.circle(frame, p, radius, _POSE_JOINT, -1, cv2.LINE_AA)
        if labels and i not in FACE:
            put_text(frame, KEYPOINT_NAMES[i], (p[0] + 8, p[1] - 8), 13, (200, 230, 255))


def draw_cursor(frame: np.ndarray, point: np.ndarray, gesture: Gesture,
                color: tuple[int, int, int], thickness: int) -> None:
    """Draw pen cursor."""
    p = tuple(np.asarray(point, dtype=int))
    if gesture == Gesture.DRAW:
        cv2.circle(frame, p, max(4, thickness), color, -1, cv2.LINE_AA)
        cv2.circle(frame, p, max(4, thickness) + 5, (255, 255, 255), 1, cv2.LINE_AA)
    elif gesture == Gesture.MOVE:
        cv2.circle(frame, p, max(6, thickness + 4), (255, 190, 60), 2, cv2.LINE_AA)
        cv2.drawMarker(frame, p, (255, 190, 60), cv2.MARKER_CROSS, 14, 1, cv2.LINE_AA)


def draw_hud(
    frame: np.ndarray,
    *,
    gesture: Gesture,
    hands_info: list | None = None,
    mode_3d: bool,
    fps: float,
    device: str,
    color: tuple[int, int, int],
    thickness: int,
    strokes: int,
    clear_progress: float = 0.0,
    toast: str = "",
    mode_label: str | None = None,
    hint: str = "Finger draw    Fist 3D    Palm release",
) -> None:
    """Draw status overlay."""
    h, w = frame.shape[:2]

    panel(frame, 0, 0, w, 78, 0.5)
    mode = mode_label or ("3D VIEW" if mode_3d else "DRAW")
    put_text(frame, mode, (16, 10), 20, (255, 255, 255))
    put_text(frame, f"Gesture: {LABELS[gesture]}", (16, 40), 17, _ACCENT.get(gesture, (200, 200, 200)))

    hands_txt = ", ".join(f"{h}" for h, _ in (hands_info or [])) or "no hands"
    right = f"{fps:.0f} FPS   {device.upper()}   strokes {strokes}   {hands_txt}"
    rw = _render_text(right, 16, (200, 200, 200))[0].shape[1]
    put_text(frame, right, (w - rw - 16, 14), 16, (200, 200, 200))
    put_text(frame, "H help", (w - rw - 16, 40), 15, (140, 140, 140))

    panel(frame, 0, h - 46, w, 46, 0.5)
    x = 16
    for c in PALETTE:
        cv2.rectangle(frame, (x, h - 34), (x + 24, h - 12), c, -1, cv2.LINE_AA)
        if c == color:
            cv2.rectangle(frame, (x - 3, h - 37), (x + 27, h - 9), (255, 255, 255), 2, cv2.LINE_AA)
        x += 34
    put_text(frame, f"size {thickness}", (x + 10, h - 34), 16, (220, 220, 220))
    hw = _render_text(hint, 15, (170, 170, 170))[0].shape[1]
    put_text(frame, hint, (w - hw - 16, h - 32), 15, (170, 170, 170))
    cv2.circle(frame, (x + 130 + thickness, h - 23), max(1, thickness // 2), color, -1, cv2.LINE_AA)

    if clear_progress > 0:
        bw = int(260 * min(1.0, clear_progress))
        cv2.rectangle(frame, (w // 2 - 130, h - 78), (w // 2 + 130, h - 62), (40, 40, 40), -1)
        cv2.rectangle(frame, (w // 2 - 130, h - 78), (w // 2 - 130 + bw, h - 62), (80, 80, 255), -1)
        put_text(frame, "grabbing", (w // 2 - 30, h - 104), 16, (200, 240, 255))

    if toast:
        tw = _render_text(toast, 18, (255, 255, 255))[0].shape[1]
        panel(frame, w // 2 - tw // 2 - 14, 92, tw + 28, 36, 0.65)
        put_text(frame, toast, (w // 2 - tw // 2, 100), 18, (255, 255, 255))


def draw_debug(frame: np.ndarray, hands, states) -> None:
    """Draw classifier debug panel."""
    names = ("thumb", "index", "middl", "ring ", "pinky")
    y = 96
    for hand, st in zip(hands, states):
        panel(frame, 12, y, 300, 24 + 16 * 7, 0.66)
        yy = y + 16
        cv2.putText(frame, f"{st.handedness[:4]} conf {st.confidence:.2f} "
                           f"{'stable' if st.stable else 'JITTER'}",
                    (20, yy), cv2.FONT_HERSHEY_SIMPLEX, 0.4, (255, 255, 255), 1, cv2.LINE_AA)
        yy += 16
        for i, name in enumerate(names):
            ratio = st.ratios[i] if i < len(st.ratios) else 1.0
            curl = st.curls[i] if i < len(st.curls) else 0.0
            up = st.fingers[i]
            col = (110, 240, 110) if up else (140, 140, 220)
            bar = "#" * int(min(max(ratio - 0.7, 0) * 12, 10))
            cv2.putText(frame, f"{name} x{ratio:4.2f} {curl:3.0f}d "
                               f"{'UP  ' if up else 'down'} {bar}",
                        (20, yy), cv2.FONT_HERSHEY_SIMPLEX, 0.4, col, 1, cv2.LINE_AA)
            yy += 16
        closed = st.pinch_distance < 0.62
        cv2.putText(frame, f"pinch {st.pinch_distance:5.2f} "
                           f"{'CLOSED' if closed else 'open'}  lowconf "
                           f"{int((hand.scores < 0.25).sum())}/21",
                    (20, yy), cv2.FONT_HERSHEY_SIMPLEX, 0.4,
                    (110, 240, 110) if closed else (180, 180, 180), 1, cv2.LINE_AA)
        y += 24 + 16 * 7 + 8


def draw_help(frame: np.ndarray, lines: tuple[str, ...] = HELP_LINES) -> None:
    """Draw help overlay."""
    h, w = frame.shape[:2]
    bw, bh = min(w - 60, 720), 20 + len(lines) * 26
    x, y = (w - bw) // 2, (h - bh) // 2
    panel(frame, x, y, bw, bh, 0.78)
    cv2.rectangle(frame, (x, y), (x + bw, y + bh), (90, 90, 90), 1, cv2.LINE_AA)
    cy = y + 12
    for line in lines:
        bold = line and not line.startswith(" ")
        put_text(frame, line, (x + 22, cy), 17 if bold else 16,
                 (255, 255, 255) if bold else (215, 215, 215))
        cy += 26