"""
OCR 结果后处理（纯逻辑，无 IO）。

对 OCR 返回的原始结果做结构化解析、置信度过滤、阅读顺序修正。
不依赖任何外部资源，可独立测试。
"""

from __future__ import annotations

from typing import Any


def filter_low_confidence(
    blocks: list[dict[str, Any]],
    threshold: float = 0.5,
) -> list[dict[str, Any]]:
    """过滤低置信度结果。

    Args:
        blocks: 原始 OCR 块列表。
        threshold: 置信度阈值（默认 0.5）。

    Returns:
        过滤后的块列表。
    """
    return [b for b in blocks if b.get("confidence", 0) >= threshold]


def merge_adjacent_lines(
    blocks: list[dict[str, Any]],
    y_tolerance: float = 10.0,
) -> list[dict[str, Any]]:
    """合并同一行的相邻块。

    Args:
        blocks: OCR 块列表（需含 bbox 坐标）。
        y_tolerance: Y 轴容差（px），同一行最大差异。

    Returns:
        合并后的块列表。
    """
    if not blocks:
        return []

    sorted_blocks = sorted(blocks, key=lambda b: (_center_y(b), _center_x(b)))

    merged: list[dict[str, Any]] = []
    current = sorted_blocks[0]

    for block in sorted_blocks[1:]:
        if abs(_center_y(block) - _center_y(current)) <= y_tolerance:
            current["text"] += block["text"]
            current["confidence"] = max(current["confidence"], block["confidence"])
        else:
            merged.append(current)
            current = block

    merged.append(current)
    return merged


def extract_text(
    blocks: list[dict[str, Any]],
    separator: str = "",
) -> str:
    """从 OCR 块中提取纯文本。

    Args:
        blocks: OCR 块列表。
        separator: 块之间的分隔符。

    Returns:
        拼接后的文本。
    """
    return separator.join(b["text"] for b in blocks)


def _center_y(block: dict[str, Any]) -> float:
    """获取块的中心 Y 坐标。"""
    pts = block.get("bbox", {}).get("points", block.get("bbox", []))
    if pts and isinstance(pts, list) and len(pts) > 0:
        ys = [p[1] for p in pts if isinstance(p, (list, tuple)) and len(p) >= 2]
        return sum(ys) / len(ys) if ys else 0.0
    return 0.0


def _center_x(block: dict[str, Any]) -> float:
    """获取块的中心 X 坐标。"""
    pts = block.get("bbox", {}).get("points", block.get("bbox", []))
    if pts and isinstance(pts, list) and len(pts) > 0:
        xs = [p[0] for p in pts if isinstance(p, (list, tuple)) and len(p) >= 2]
        return sum(xs) / len(xs) if xs else 0.0
    return 0.0