# -*- coding: utf-8 -*-
"""展示层：把"点位"渲染成人能看懂的标注图，并给点位质量一个独立量尺。

两个能力都有两类调用方，所以放在**包根**而不是 `web/` 里（它不是 web 专属）：
  * `scripts/verify/send_campaign.py` —— CLI 批量实验落图
  * `tcaptcha/web` —— 界面上的题目图 / 标注图

量尺原理（`icon_centroid_offset`）：图标是近黑的线条画、背景是彩色的。在点击点周围
截一个窗口，用 Otsu 分出**暗色笔画**，取笔画质心当"图标视觉中心"，报告点击点离它多远。
这条量尺**独立于求解器**（求解器用的是 YOLO box 中心），所以能回答"到底点偏了多少"。
"""

from __future__ import annotations

from typing import Any, Optional, Sequence, Tuple

import cv2
import numpy as np

# 标注样式
_RING_RADIUS = 18
_RING_COLOR = (0, 0, 255)          # BGR 红
_IDX_COLOR = (0, 255, 0)           # BGR 绿
_CENTROID_COLOR = (255, 128, 0)    # BGR 蓝


def to_bgr(image: Any) -> np.ndarray:
    """bytes / ndarray / PIL.Image 统一转成 BGR ndarray。"""
    if isinstance(image, (bytes, bytearray)):
        arr = cv2.imdecode(np.frombuffer(bytes(image), np.uint8), cv2.IMREAD_COLOR)
        if arr is None:
            raise ValueError("无法解码图片字节")
        return arr
    if isinstance(image, np.ndarray):
        return image if image.ndim == 3 else cv2.cvtColor(image, cv2.COLOR_GRAY2BGR)
    # PIL.Image
    rgb = np.array(image.convert("RGB"))
    return cv2.cvtColor(rgb, cv2.COLOR_RGB2BGR)


def to_jpeg(image: Any, quality: int = 88) -> bytes:
    """任意输入 -> JPEG 字节（给 HTTP 响应用）。"""
    bgr = to_bgr(image) if not isinstance(image, np.ndarray) else image
    ok, buf = cv2.imencode(".jpg", bgr, [int(cv2.IMWRITE_JPEG_QUALITY), quality])
    if not ok:
        raise ValueError("JPEG 编码失败")
    return buf.tobytes()


def icon_centroid_offset(bg: Any, x: int, y: int,
                         half: int = 32) -> Optional[Tuple[float, float, float]]:
    """点击点 vs 该处图标**暗色笔画质心**。

    返回 `(质心x, 质心y, 离点击点的距离px)`；窗口里笔画太少（估不出中心）时返回 None。
    """
    bgr = to_bgr(bg)
    h, w = bgr.shape[:2]
    x0, y0 = max(0, x - half), max(0, y - half)
    x1, y1 = min(w, x + half), min(h, y + half)
    patch = bgr[y0:y1, x0:x1]
    if patch.size == 0:
        return None
    gray = cv2.cvtColor(patch, cv2.COLOR_BGR2GRAY)
    _, binary = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)
    ys, xs = np.nonzero(binary)
    if len(xs) < 20:
        return None
    cx, cy = float(xs.mean()) + x0, float(ys.mean()) + y0
    return (cx, cy, float(np.hypot(cx - x, cy - y)))


def annotate_points(bg: Any,
                    points: Sequence[Sequence[int]],
                    prompt: Any = None,
                    offsets: Optional[Sequence[Optional[float]]] = None,
                    centroids: Optional[Sequence[Optional[Sequence[float]]]] = None,
                    title: str = "",
                    embed_prompt: bool = True) -> bytes:
    """在底图上按**点击顺序**画编号红圈，可选贴提示图、标出质心与偏差。

    参数:
      points        点击点序列（背景图原始像素），**顺序即答案顺序**
      prompt        提示图（图标/文字点选题）
      offsets       每个点离图标笔画质心的距离（px），标在圈上
      centroids     每个点的质心坐标，画一个蓝色十字（一眼看出偏没偏）
      title         左上角标题（如 "第 1 题"）
      embed_prompt  是否把提示图贴进右上角。命令行/落盘单图查看时贴（默认 True）；
                    **Web 界面传 False** —— 那边提示图是独立一张缩略图，
                    贴进去只会挡住右上角的图标（实测会遮住一个目标）。"""
    bgr = to_bgr(bg)
    for i, pt in enumerate(points):
        x, y = int(pt[0]), int(pt[1])
        cv2.circle(bgr, (x, y), _RING_RADIUS, _RING_COLOR, 2)
        cv2.circle(bgr, (x, y), 2, _RING_COLOR, -1)
        label = str(i + 1)
        cv2.putText(bgr, label, (x - 8, y - _RING_RADIUS - 6),
                    cv2.FONT_HERSHEY_SIMPLEX, 0.85, _IDX_COLOR, 2)
        if centroids and i < len(centroids) and centroids[i]:
            cx, cy = int(centroids[i][0]), int(centroids[i][1])
            cv2.drawMarker(bgr, (cx, cy), _CENTROID_COLOR, cv2.MARKER_CROSS, 12, 1)
        if offsets and i < len(offsets) and offsets[i] is not None:
            cv2.putText(bgr, "%.0fpx" % offsets[i], (x - 20, y + _RING_RADIUS + 16),
                        cv2.FONT_HERSHEY_SIMPLEX, 0.5, _CENTROID_COLOR, 1)
    if prompt is not None and embed_prompt:
        try:
            pr = to_bgr(prompt)
            ph = max(1, bgr.shape[0] // 4)
            pw = max(1, int(pr.shape[1] * ph / pr.shape[0]))
            pr = cv2.resize(pr, (pw, ph))
            x0, y0 = max(0, bgr.shape[1] - pw - 4), 4
            bgr[y0:y0 + ph, x0:x0 + pw] = pr
            cv2.rectangle(bgr, (x0, y0), (x0 + pw, y0 + ph), (255, 255, 255), 1)
        except Exception:                       # noqa: BLE001  提示图坏了不影响主流程
            pass
    if title:
        cv2.putText(bgr, title, (6, 20), cv2.FONT_HERSHEY_SIMPLEX, 0.6, (255, 255, 255), 3)
        cv2.putText(bgr, title, (6, 20), cv2.FONT_HERSHEY_SIMPLEX, 0.6, (0, 0, 0), 1)
    return to_jpeg(bgr)