from __future__ import annotations

from dataclasses import dataclass
from pathlib import Path
from typing import Any, Dict, Tuple

import numpy as np


def _safe_float(v: Any, default: float) -> float:
    try:
        return float(v)
    except Exception:
        return float(default)


def _safe_int(v: Any, default: int) -> int:
    try:
        return int(v)
    except Exception:
        return int(default)


def _as_bool(v: Any, default: bool) -> bool:
    if v is None:
        return default
    if isinstance(v, bool):
        return v
    if isinstance(v, (int, float)):
        return bool(v)
    return str(v).strip().lower() in ("1", "true", "yes", "on")


@dataclass
class NavigationExportConfig:
    enabled: bool = True
    min_points: int = 400
    resolution_m: float = 0.05
    z_min_m: float = 0.05   # 5 cm above floor — avoids ground returns, captures low obstacles
    z_max_m: float = 1.40   # 1.4 m — covers G1 Edu body (1.25 m) with margin
    inflation_radius_m: float = 0.20
    padding_m: float = 0.40

    @staticmethod
    def from_dict(d: Dict[str, Any] | None) -> "NavigationExportConfig":
        src = d or {}
        return NavigationExportConfig(
            enabled=_as_bool(src.get("enabled", True), True),
            min_points=max(50, _safe_int(src.get("min_points", 400), 400)),
            resolution_m=max(0.01, _safe_float(src.get("resolution_m", 0.05), 0.05)),
            z_min_m=_safe_float(src.get("z_min_m", -0.40), -0.40),
            z_max_m=_safe_float(src.get("z_max_m", 1.20), 1.20),
            inflation_radius_m=max(0.0, _safe_float(src.get("inflation_radius_m", 0.20), 0.20)),
            padding_m=max(0.0, _safe_float(src.get("padding_m", 0.40), 0.40)),
        )

    def patched(self, patch: Dict[str, Any] | None) -> "NavigationExportConfig":
        src = patch or {}
        cur = self
        return NavigationExportConfig(
            enabled=_as_bool(src.get("enabled", cur.enabled), cur.enabled),
            min_points=max(50, _safe_int(src.get("min_points", cur.min_points), cur.min_points)),
            resolution_m=max(0.01, _safe_float(src.get("resolution_m", cur.resolution_m), cur.resolution_m)),
            z_min_m=_safe_float(src.get("z_min_m", cur.z_min_m), cur.z_min_m),
            z_max_m=_safe_float(src.get("z_max_m", cur.z_max_m), cur.z_max_m),
            inflation_radius_m=max(
                0.0,
                _safe_float(src.get("inflation_radius_m", cur.inflation_radius_m), cur.inflation_radius_m),
            ),
            padding_m=max(0.0, _safe_float(src.get("padding_m", cur.padding_m), cur.padding_m)),
        )


def _inflate_binary(mask: np.ndarray, radius_cells: int) -> np.ndarray:
    if radius_cells <= 0:
        return mask.copy()
    h, w = mask.shape
    out = mask.copy()
    offsets = []
    rr = radius_cells * radius_cells
    for dy in range(-radius_cells, radius_cells + 1):
        for dx in range(-radius_cells, radius_cells + 1):
            if (dy * dy + dx * dx) <= rr:
                offsets.append((dy, dx))
    for dy, dx in offsets:
        ys = max(0, -dy)
        ye = min(h, h - dy)
        xs = max(0, -dx)
        xe = min(w, w - dx)
        yd = max(0, dy)
        xd = max(0, dx)
        out[yd : yd + (ye - ys), xd : xd + (xe - xs)] |= mask[ys:ye, xs:xe]
    return out


def _sanitize_basename(name: str) -> str:
    base = (name or "").strip() or "map"
    for bad in ("/", "\\", ":", "*", "?", "\"", "<", ">", "|"):
        base = base.replace(bad, "_")
    return base


class NavigationExporter:
    def __init__(self, cfg: NavigationExportConfig, data_folder: str):
        self.cfg = cfg
        self.data_folder = Path(data_folder)
        self.data_folder.mkdir(parents=True, exist_ok=True)

    def update_config(self, cfg: NavigationExportConfig) -> None:
        self.cfg = cfg

    def _filter_nav_points(self, points: np.ndarray) -> np.ndarray:
        pts = np.asarray(points, dtype=np.float32)
        if pts.ndim != 2 or pts.shape[1] < 3:
            raise RuntimeError("Invalid point array for navigation export.")
        zmin, zmax = float(self.cfg.z_min_m), float(self.cfg.z_max_m)
        m = (pts[:, 2] >= zmin) & (pts[:, 2] <= zmax)
        return pts[m]

    def count_nav_points(self, points: np.ndarray) -> int:
        try:
            return int(len(self._filter_nav_points(points)))
        except Exception:
            return 0

    def _build_grid(self, points: np.ndarray) -> Tuple[np.ndarray, np.ndarray, np.ndarray]:
        pts = self._filter_nav_points(points)
        if len(pts) < int(self.cfg.min_points):
            raise RuntimeError(f"Not enough points for nav export ({len(pts)}).")

        res = float(self.cfg.resolution_m)
        pad = float(self.cfg.padding_m)

        min_xy = pts[:, :2].min(axis=0) - pad
        max_xy = pts[:, :2].max(axis=0) + pad
        span = np.maximum(max_xy - min_xy, res)
        w = int(np.ceil(span[0] / res)) + 1
        h = int(np.ceil(span[1] / res)) + 1

        occ = np.zeros((h, w), dtype=bool)
        gx = np.clip(((pts[:, 0] - min_xy[0]) / res).astype(np.int32), 0, w - 1)
        gy = np.clip(((pts[:, 1] - min_xy[1]) / res).astype(np.int32), 0, h - 1)
        occ[gy, gx] = True

        rad_cells = int(np.ceil(float(self.cfg.inflation_radius_m) / res))
        inf = _inflate_binary(occ, rad_cells)

        return occ, inf, min_xy

    def export(self, base_name: str, points: np.ndarray) -> Dict[str, Any]:
        if not self.cfg.enabled:
            raise RuntimeError("Navigation export is disabled in config.")

        occ, inf, min_xy = self._build_grid(points)
        base = _sanitize_basename(base_name)
        folder = self.data_folder

        pgm_name = f"{base}_nav.pgm"
        yaml_name = f"{base}_nav.yaml"
        cost_name = f"{base}_costmap.npy"
        n = 1
        while (folder / pgm_name).exists() or (folder / yaml_name).exists() or (folder / cost_name).exists():
            pgm_name = f"{base}_nav({n}).pgm"
            yaml_name = f"{base}_nav({n}).yaml"
            cost_name = f"{base}_costmap({n}).npy"
            n += 1

        # ROS map image: 0=occupied, 254=free
        img = np.where(inf, 0, 254).astype(np.uint8)
        img = np.flipud(img)  # image origin top-left, map origin bottom-left

        pgm_path = folder / pgm_name
        with open(pgm_path, "wb") as f:
            h, w = img.shape
            f.write(f"P5\n{w} {h}\n255\n".encode("ascii"))
            f.write(img.tobytes())

        yaml_path = folder / yaml_name
        # Write proper YAML — NOT json.dumps (quoted keys break ROS2 Nav2 map_server)
        ox, oy = float(min_xy[0]), float(min_xy[1])
        yaml_lines = [
            f"image: {pgm_name}",
            f"resolution: {float(self.cfg.resolution_m):.6f}",
            f"origin: [{ox:.6f}, {oy:.6f}, 0.000000]",
            "negate: 0",
            "occupied_thresh: 0.65",
            "free_thresh: 0.196",
            "mode: trinary",  # required by Nav2 map_server
        ]
        yaml_path.write_text("\n".join(yaml_lines) + "\n", encoding="utf-8")

        cost = np.zeros_like(img, dtype=np.uint8)
        occ_img = np.flipud(occ)
        inf_img = np.flipud(inf)
        cost[inf_img] = 180
        cost[occ_img] = 255
        cost_path = folder / cost_name
        np.save(cost_path, cost)

        return {
            "pgm": str(pgm_path),
            "yaml": str(yaml_path),
            "costmap": str(cost_path),
            "shape": [int(img.shape[0]), int(img.shape[1])],
            "occupied_cells": int(np.count_nonzero(occ)),
            "inflated_cells": int(np.count_nonzero(inf)),
        }