"""Geometry schema normalization (v1.0 and v2.0 typed-segment support)."""

from __future__ import annotations

import math
from copy import deepcopy
from typing import Any, Dict, List

import numpy as np
from shapely.geometry import Polygon

from src.shared.arc_utils import arc_to_polyline


def _as_xy(pt: Any) -> List[float]:
    return [float(pt[0]), float(pt[1])]


def _arc_span(seg: Dict[str, Any]) -> float:
    cx, cy = _as_xy(seg["center"])
    sx, sy = _as_xy(seg["start"])
    ex, ey = _as_xy(seg["end"])

    a0 = math.atan2(sy - cy, sx - cx)
    a1 = math.atan2(ey - cy, ex - cx)
    cw = bool(seg.get("clockwise", False))

    if abs(sx - ex) < 1e-9 and abs(sy - ey) < 1e-9:
        return 2.0 * math.pi

    if cw:
        if a1 > a0:
            a1 -= 2.0 * math.pi
    else:
        if a1 < a0:
            a1 += 2.0 * math.pi
    return abs(a1 - a0)


def _typed_segments_to_polyline_v2(segments: List[Dict[str, Any]], full_circle_segments: int = 32) -> List[List[float]]:
    out: List[List[float]] = []

    for seg in segments or []:
        stype = seg.get("type", "line")
        if stype == "arc":
            span = _arc_span(seg)
            n_seg = max(2, int(round(full_circle_segments * span / (2.0 * math.pi))))
            pts = arc_to_polyline(seg, n_pts=n_seg + 1)
        else:
            pts = [_as_xy(seg["start"]), _as_xy(seg["end"])]

        if out and pts:
            if abs(out[-1][0] - pts[0][0]) < 1e-9 and abs(out[-1][1] - pts[0][1]) < 1e-9:
                out.extend(pts[1:])
            else:
                out.extend(pts)
        else:
            out.extend(pts)

    if len(out) >= 2 and abs(out[0][0] - out[-1][0]) < 1e-9 and abs(out[0][1] - out[-1][1]) < 1e-9:
        out = out[:-1]

    return out


def _inner_boundary_to_hole(inner: Dict[str, Any], default_weight: float = 0.5) -> Dict[str, Any]:
    segments = inner.get("segments", [])
    boundary = _typed_segments_to_polyline_v2(segments)

    # Circular hole detection: single full-circle arc
    is_circular = False
    center = None
    diameter = None
    if len(segments) == 1 and segments[0].get("type") == "arc":
        seg = segments[0]
        s = _as_xy(seg["start"])
        e = _as_xy(seg["end"])
        if abs(s[0] - e[0]) < 1e-8 and abs(s[1] - e[1]) < 1e-8:
            is_circular = True
            center = _as_xy(seg["center"])
            diameter = 2.0 * float(seg["radius"])

    if center is None or diameter is None:
        if len(boundary) >= 3:
            poly = Polygon(boundary)
            if poly.is_valid and not poly.is_empty:
                c = poly.centroid
                center = [float(c.x), float(c.y)]
                minx, miny, maxx, maxy = poly.bounds
                diameter = float(max(maxx - minx, maxy - miny))
            else:
                arr = np.asarray(boundary, dtype=float)
                center = [float(np.mean(arr[:, 0])), float(np.mean(arr[:, 1]))]
                diameter = float(max(np.ptp(arr[:, 0]), np.ptp(arr[:, 1])))
        else:
            center = [0.0, 0.0]
            diameter = 1.0

    return {
        "index": int(inner.get("index", 0)),
        "center": center,
        "diameter": float(diameter),
        "boundary": boundary,
        "is_circular": bool(is_circular),
        "weight": float(inner.get("weight", default_weight)),
    }


def normalize_geometry_schema(geometry: Dict[str, Any]) -> Dict[str, Any]:
    """Return geometry in legacy Brain format (outer_boundary + holes), preserving typed data."""
    schema_version = str(geometry.get("schema_version", "1.0"))

    if schema_version.startswith("1"):
        out = deepcopy(geometry)
        out.setdefault("holes", [])
        return out

    if not schema_version.startswith("2"):
        # Unknown schema: best effort fallback (assume legacy fields are present)
        out = deepcopy(geometry)
        out.setdefault("holes", [])
        return out

    out = deepcopy(geometry)
    typed_outer = out.get("outer_boundary_typed", [])
    if typed_outer:
        out["outer_boundary"] = _typed_segments_to_polyline_v2(typed_outer)

    inner_boundaries = out.get("inner_boundaries", [])
    out["holes"] = [_inner_boundary_to_hole(inner) for inner in inner_boundaries]

    return out