"""GIS layer export / reprojection / geometry operations (/api/gis/export, /op, /reproject)."""
import io
import os
import tempfile
import zipfile

import numpy as np
import pyogrio
import pytest
import shapely
from fastapi.testclient import TestClient
from pyproj import Transformer

from backend import gisops
from backend.batch import BatchError
from backend.main import app

EPSG = "EPSG:5186"
TO_WGS = Transformer.from_crs(EPSG, "EPSG:4326", always_xy=True)


def wgs(x, y):
    return list(TO_WGS.transform(x, y))


def fc(features):
    return {"type": "FeatureCollection", "features": features}


SQUARE = fc([{"type": "Feature", "properties": {"name": "블록A", "dia": 150}, "geometry": {"type": "Polygon", "coordinates": [[wgs(200000, 500000), wgs(200100, 500000), wgs(200100, 500100), wgs(200000, 500100), wgs(200000, 500000)]]}}])
LINES = fc([
    {"type": "Feature", "properties": {"id": "P1", "dia": 150}, "geometry": {"type": "LineString", "coordinates": [wgs(200000, 500000), wgs(200200, 500000)]}},
    {"type": "Feature", "properties": {"id": "P2", "dia": None}, "geometry": {"type": "LineString", "coordinates": [wgs(200200, 500000), wgs(200200, 500200)]}},
])


@pytest.fixture(scope="module")
def client():
    with TestClient(app, raise_server_exceptions=False) as c:
        yield c


def _area_m2(feature_collection):
    from shapely.geometry import shape
    g = gisops._project(np.array([shape(f["geometry"]) for f in feature_collection["features"]], dtype=object), gisops.WGS84, gisops.CRS.from_user_input(EPSG))
    return float(sum(x.area for x in g))


def test_export_shapefile_in_target_crs_with_korean_fields():
    data, name, media = gisops.write_vector(LINES, EPSG, "shp", "관로")
    assert name == "관로.zip" and media == "application/zip"
    with tempfile.TemporaryDirectory() as tmp:
        zipfile.ZipFile(io.BytesIO(data)).extractall(tmp)
        shp = [f for f in os.listdir(tmp) if f.endswith(".shp")][0]
        df_info = pyogrio.read_info(os.path.join(tmp, shp))
        assert "5186" in df_info["crs"] and df_info["features"] == 2
        meta, _, geom, fields = pyogrio.raw.read(os.path.join(tmp, shp))
        x0 = shapely.from_wkb(geom[0]).coords[0][0]
        assert x0 == pytest.approx(200000, abs=0.01)
        assert list(meta["fields"]) == ["id", "dia"]


def test_export_gpkg_dxf_and_mixed_shapefile_refused():
    gpkg, name, _ = gisops.write_vector(SQUARE, EPSG, "gpkg", "blocks")
    assert name == "blocks.gpkg" and gpkg[:15] == b"SQLite format 3"
    dxf, _, _ = gisops.write_vector(LINES, EPSG, "dxf", "lines")
    assert b"SECTION" in dxf
    mixed = fc(SQUARE["features"] + LINES["features"])
    with pytest.raises(BatchError):
        gisops.write_vector(mixed, EPSG, "shp", "x")


def test_reproject_fixes_a_layer_read_in_the_wrong_crs():
    # Numbers really in EPSG:5186 but read as EPSG:5187: reassign -> lands on the 5186 position.
    wrong = Transformer.from_crs("EPSG:5187", "EPSG:4326", always_xy=True)
    bad = fc([{"type": "Feature", "properties": {}, "geometry": {"type": "Point", "coordinates": list(wrong.transform(200000, 500000))}}])
    fixed = gisops.reproject_fc(bad, "EPSG:5187", EPSG)
    assert fixed["features"][0]["geometry"]["coordinates"] == pytest.approx(wgs(200000, 500000), abs=1e-8)


def test_buffer_clip_difference_dissolve():
    buf = gisops.vector_op("buffer", {"crs": EPSG, "layer": LINES, "distance": 10})
    assert len(buf["features"]) == 2 and buf["features"][0]["properties"]["id"] == "P1"
    # P1 buffered: 200 x 20 rectangle + two half-discs of r=10
    from shapely.geometry import shape
    a = gisops._project(np.array([shape(buf["features"][0]["geometry"])], dtype=object), gisops.WGS84, gisops.CRS.from_user_input(EPSG))[0].area
    assert a == pytest.approx(200 * 20 + np.pi * 100, rel=0.01)
    clipped = gisops.vector_op("clip", {"crs": EPSG, "layer": LINES, "other": SQUARE})
    assert len(clipped["features"]) == 1  # only P1 crosses the square
    diff = gisops.vector_op("difference", {"crs": EPSG, "layer": SQUARE, "other": buf})
    assert _area_m2(diff) < 100 * 100
    dis = gisops.vector_op("dissolve", {"crs": EPSG, "layer": buf, "field": None})
    assert len(dis["features"]) == 1 and dis["features"][0]["properties"]["count"] == 2


def test_voronoi_and_grid():
    pts = [[200000, 500000], [200100, 500000], [200000, 500100], [200100, 500100], [200050, 500050]]
    v = gisops.vector_op("voronoi", {"crs": EPSG, "points": pts, "ids": ["A", "B", "C", "D", "E"]})
    assert sorted(f["properties"]["node"] for f in v["features"]) == ["A", "B", "C", "D", "E"]
    g = gisops.vector_op("grid", {"crs": EPSG, "bounds": [200000, 500000, 200100, 500050], "cell": 25})
    assert len(g["features"]) == 8
    with pytest.raises(BatchError):
        gisops.vector_op("grid", {"crs": "EPSG:4326", "bounds": [0, 0, 1, 1], "cell": 1})


def test_http(client):
    r = client.post("/api/gis/export", json={"featureCollection": LINES, "crs": EPSG, "format": "geojson", "name": "관로"})
    assert r.status_code == 200 and "attachment" in r.headers["content-disposition"]
    r = client.post("/api/gis/op", json={"op": "buffer", "crs": EPSG, "layer": LINES, "distance": 5})
    assert r.status_code == 200 and len(r.json()["features"]) == 2
    assert client.post("/api/gis/op", json={"op": "nope", "crs": EPSG, "layer": LINES}).status_code == 400