#!/usr/bin/env python3
"""Render a static slippy-map image centred on a coordinate, with a marker.

Used by the Location quad because libshumate does not render tiles in this
environment (the official shumate-demo shows the same blank map — a library/GTK
render bug), while plain tile downloads work fine. Stitches raster tiles into one
PNG with Pillow and caches them. The quad re-renders this at a new centre to pan.

  staticmap.py <center_lat> <center_lon> <zoom> <w> <h> <out> \
               [style] [marker_lat] [marker_lon]

  style: dark (default, CartoDB dark_matter) | satellite (Esri) | standard (OSM)
  marker_*: where to draw the location pin; defaults to the centre. When the centre
            is panned away, the pin clamps to the nearest edge so it stays visible.
"""

from __future__ import annotations

import io
import math
import os
import sys
import urllib.request
from pathlib import Path

from PIL import Image, ImageDraw

TILE = 256
CACHE = Path(os.environ.get("XDG_CACHE_HOME", Path.home() / ".cache")) / "astro-menu" / "tiles"
UA = "astro-menu/1.0 (personal dotfiles)"
BG = (26, 26, 26)
ACCENT = (228, 0, 70)

STYLES = {
    "standard":  "https://tile.openstreetmap.org/{z}/{x}/{y}.png",
    "dark":      "https://a.basemaps.cartocdn.com/dark_all/{z}/{x}/{y}.png",
    "satellite": "https://server.arcgisonline.com/ArcGIS/rest/services/"
                 "World_Imagery/MapServer/tile/{z}/{y}/{x}",
}


def _center_px(lat: float, lon: float, zoom: int) -> tuple[float, float]:
    n = 2 ** zoom
    lat_r = math.radians(lat)
    x = (lon + 180.0) / 360.0 * n
    y = (1.0 - math.asinh(math.tan(lat_r)) / math.pi) / 2.0 * n
    return x * TILE, y * TILE


def _tile(z: int, x: int, y: int, style: str) -> Image.Image | None:
    CACHE.mkdir(parents=True, exist_ok=True)
    fp = CACHE / f"{style}_{z}_{x}_{y}.png"
    if fp.exists():
        try:
            return Image.open(fp).convert("RGB")
        except Exception:
            pass
    url = STYLES[style].format(z=z, x=x, y=y)
    try:
        req = urllib.request.Request(url, headers={"User-Agent": UA})
        data = urllib.request.urlopen(req, timeout=8).read()
    except Exception as exc:
        print(f"tile {style} {z}/{x}/{y}: {exc}", file=sys.stderr)
        return None
    img = Image.open(io.BytesIO(data)).convert("RGB")
    img.save(fp)   # normalise to PNG in the cache (satellite is served as JPEG)
    return img


def render(lat: float, lon: float, zoom: int, w: int, h: int, out: str,
           style: str = "dark", marker: tuple[float, float] | None = None) -> None:
    if style not in STYLES:
        style = "dark"
    n = 2 ** zoom
    cx, cy = _center_px(lat, lon, zoom)
    left, top = cx - w / 2, cy - h / 2
    img = Image.new("RGB", (w, h), BG)
    x0, x1 = int(left // TILE), int((left + w) // TILE)
    y0, y1 = int(top // TILE), int((top + h) // TILE)
    for tx in range(x0, x1 + 1):
        for ty in range(y0, y1 + 1):
            if ty < 0 or ty >= n:
                continue
            tile = _tile(zoom, tx % n, ty, style)
            if tile is None:
                continue
            img.paste(tile, (int(tx * TILE - left), int(ty * TILE - top)))

    # marker at the real location (defaults to centre); clamp to the edge so it stays
    # on-screen when the view is panned away from it.
    mlat, mlon = marker if marker else (lat, lon)
    mwx, mwy = _center_px(mlat, mlon, zoom)
    r = 8
    mx = max(r, min(w - r, mwx - left))
    my = max(r, min(h - r, mwy - top))
    d = ImageDraw.Draw(img)
    d.ellipse([mx - r, my - r, mx + r, my + r], fill=ACCENT, outline=(255, 255, 255), width=2)

    Path(out).parent.mkdir(parents=True, exist_ok=True)
    img.save(out)


if __name__ == "__main__":
    a = sys.argv
    style = a[7] if len(a) > 7 else "dark"
    marker = (float(a[8]), float(a[9])) if len(a) > 9 else None
    render(float(a[1]), float(a[2]), int(a[3]), int(a[4]), int(a[5]), a[6], style, marker)
    print(a[6])