"""Right-of-way estimation geometry — the street-aware extension and its fallbacks.

`build_estimation_geometry` is pure; we drive it with synthetic street/neighbor
callbacks over a real Omaha UTM square so the WGS84<->UTM math is faithful. These
lock in: exact extension area, corner-lot dual frontage, phantom removal via
neighbor subtraction (no-street fallback), and no bleed into an attached unit.
"""

from __future__ import annotations

import pytest
from pyproj import Transformer
from shapely.geometry import LineString
from shapely.ops import transform as shp_tf

from conftest import (
    CENTER_LAT,
    CENTER_LON,
    OMAHA_CX,
    OMAHA_CY,
    SQFT_PER_SQM,
    rect_utm,
    square_utm,
    utm_to_wgs,
)
from lawn_estimator.geometry import (
    area_per_pixel_sqft,
    build_estimation_geometry,
    geometry_area_sqft,
    geometry_exceeds_frame,
)

CRS = "EPSG:26914"
BUFFER_FT = 12.0
DIST_M = BUFFER_FT * 0.3048  # 3.6576 m
SIZE_M = 30.0


def _street(name, line_utm):
    return (name, utm_to_wgs(line_utm))


def _streets_fn(*named_lines):
    return lambda bounds: list(named_lines)


def _neighbors_fn(*polys_wgs):
    return lambda bounds, exclude_id: list(polys_wgs)


# A horizontal centerline 10 m south of the parcel's south edge (within the 22 m
# street-detection window), and a vertical one 10 m east of the east edge.
SOUTH_STREET = _street("South St", LineString([(OMAHA_CX - 50, OMAHA_CY - 25),
                                               (OMAHA_CX + 50, OMAHA_CY - 25)]))
EAST_STREET = _street("East St", LineString([(OMAHA_CX + 25, OMAHA_CY - 50),
                                             (OMAHA_CX + 25, OMAHA_CY + 50)]))


def test_single_frontage_extension_exact_area():
    parcel = utm_to_wgs(square_utm(OMAHA_CX, OMAHA_CY, SIZE_M))
    _, est_utm, area_sqft, extensions = build_estimation_geometry(
        parcel, BUFFER_FT, CRS,
        fetch_neighbors=_neighbors_fn(),  # no neighbors
        fetch_streets=_streets_fn(SOUTH_STREET),
    )

    assert len(extensions) == 1
    ext = extensions[0]
    assert ext["street"] == "South St"
    assert ext["street_facing"] is True
    # One edge (30 m) extended by 12 ft (3.6576 m).
    expected_ext = SIZE_M * DIST_M * SQFT_PER_SQM  # ~1181.1 sqft
    assert ext["area_sqft"] == pytest.approx(expected_ext, rel=2e-3)
    expected_total = (SIZE_M * SIZE_M + SIZE_M * DIST_M) * SQFT_PER_SQM
    assert area_sqft == pytest.approx(expected_total, rel=2e-3)


def test_corner_lot_gets_two_named_frontages_only():
    parcel = utm_to_wgs(square_utm(OMAHA_CX, OMAHA_CY, SIZE_M))
    _, _, area_sqft, extensions = build_estimation_geometry(
        parcel, BUFFER_FT, CRS,
        fetch_neighbors=_neighbors_fn(),
        fetch_streets=_streets_fn(SOUTH_STREET, EAST_STREET),
    )

    # Two street-facing edges → two frontages; the north/west edges get nothing.
    assert len(extensions) == 2
    assert {e["street"] for e in extensions} == {"South St", "East St"}
    per_edge = SIZE_M * DIST_M * SQFT_PER_SQM
    assert sum(e["area_sqft"] for e in extensions) == pytest.approx(2 * per_edge, rel=2e-3)


def test_no_street_data_extends_all_then_neighbor_subtraction_removes_phantom():
    parcel = utm_to_wgs(square_utm(OMAHA_CX, OMAHA_CY, SIZE_M))
    north_neighbor = utm_to_wgs(rect_utm(OMAHA_CX, OMAHA_CY + SIZE_M, SIZE_M, SIZE_M))

    # Fallback path: no street source → extend every edge (~4 strips).
    _, _, area_no, ext_no = build_estimation_geometry(
        parcel, BUFFER_FT, CRS, fetch_neighbors=_neighbors_fn(), fetch_streets=None)
    _, est_with, area_with, ext_with = build_estimation_geometry(
        parcel, BUFFER_FT, CRS, fetch_neighbors=_neighbors_fn(north_neighbor), fetch_streets=None)

    one_strip = SIZE_M * DIST_M * SQFT_PER_SQM  # ~1181 sqft
    # The north neighbor carves one phantom strip out of both the area and the report.
    assert area_no - area_with == pytest.approx(one_strip, rel=5e-2)
    assert (sum(e["area_sqft"] for e in ext_no) - sum(e["area_sqft"] for e in ext_with)
            == pytest.approx(one_strip, rel=5e-2))

    # And the estimate never bleeds into the neighbor lot.
    to_utm = Transformer.from_crs("EPSG:4326", CRS, always_xy=True).transform
    assert est_with.intersection(shp_tf(to_utm, north_neighbor)).area == pytest.approx(0.0, abs=1.0)
    # No-street extensions are reported unverified (street_facing is None).
    assert all(e["street"] is None and e["street_facing"] is None for e in ext_with)


def test_attached_unit_no_bleed_into_neighbor_parcel():
    # A duplex is one parcel per unit; a narrow lot with an adjoining unit to the
    # east must not extend into that unit even in the extend-all fallback.
    parcel = utm_to_wgs(rect_utm(OMAHA_CX, OMAHA_CY, 10.0, 30.0))
    east_unit_utm = rect_utm(OMAHA_CX + 10.0, OMAHA_CY, 10.0, 30.0)  # shares the east edge
    east_unit = utm_to_wgs(east_unit_utm)

    _, est_utm, _, _ = build_estimation_geometry(
        parcel, BUFFER_FT, CRS,
        fetch_neighbors=_neighbors_fn(east_unit), fetch_streets=None)

    to_utm = Transformer.from_crs("EPSG:4326", CRS, always_xy=True).transform
    neighbor_utm = shp_tf(to_utm, east_unit)
    overlap = est_utm.intersection(neighbor_utm).area
    assert overlap == pytest.approx(0.0, abs=1.0)  # no measurable bleed


# ---------------------------------------------------------------------------
# Adaptive ROW-to-curb (row_to_curb flag): extend a deep-setback frontage toward
# the actual centerline (≈ the curb) instead of the flat 12 ft, floored at 12 ft
# (never shrinks a frontage) and capped at 25 ft (wide arterials can't blow up).
# ---------------------------------------------------------------------------
HALF_ROAD_FT = 15.0
CAP_FT = 25.0
HALF_ROAD_M = HALF_ROAD_FT * 0.3048  # 4.572 m — half a typical residential road
CAP_M = CAP_FT * 0.3048              # 7.62 m


def _south_street_at(offset_m, name="South St"):
    """Horizontal centerline `offset_m` south of the 30 m parcel's south edge, so
    the south frontage's measured centerline distance is exactly `offset_m`. The
    line spans only ±12 m (< the 15 m half-width) so the side edges' nearest point
    is an inward endpoint → cleanly rejected by the outward-side test, isolating a
    single south frontage regardless of how close the street sits."""
    y = OMAHA_CY - SIZE_M / 2 - offset_m
    return _street(name, LineString([(OMAHA_CX - 12, y), (OMAHA_CX + 12, y)]))


def _front_ext(offset_m, *, row_to_curb):
    """(front extension sqft, total estimation sqft) for a lone south frontage
    whose centerline sits `offset_m` out."""
    parcel = utm_to_wgs(square_utm(OMAHA_CX, OMAHA_CY, SIZE_M))
    _, _, area_sqft, extensions = build_estimation_geometry(
        parcel, BUFFER_FT, CRS,
        fetch_neighbors=_neighbors_fn(),
        fetch_streets=_streets_fn(_south_street_at(offset_m)),
        row_to_curb=row_to_curb,
        road_half_width_ft=HALF_ROAD_FT,
        row_curb_cap_ft=CAP_FT,
    )
    assert len(extensions) == 1  # only the south edge faces the street
    return extensions[0]["area_sqft"], area_sqft


def test_row_to_curb_reaches_curb_on_deep_setback():
    # Centerline 10 m out → curb ≈ 10 − 4.572 = 5.428 m past the property line,
    # well beyond the flat 12 ft (3.6576 m) strip.
    ext, _ = _front_ext(10.0, row_to_curb=True)
    expected = SIZE_M * (10.0 - HALF_ROAD_M) * SQFT_PER_SQM  # ~1752.8 sqft
    assert ext == pytest.approx(expected, rel=3e-3)
    flat, _ = _front_ext(10.0, row_to_curb=False)
    assert ext > flat  # adaptive reaches farther than the flat strip


def test_row_to_curb_capped_on_very_deep_setback():
    # Centerline 16 m out → 16 − 4.572 = 11.428 m would overshoot; capped at 25 ft.
    ext, _ = _front_ext(16.0, row_to_curb=True)
    expected = SIZE_M * CAP_M * SQFT_PER_SQM  # ~2460.7 sqft
    assert ext == pytest.approx(expected, rel=3e-3)


def test_row_to_curb_floors_at_flat_strip_on_shallow_setback():
    # Centerline 5 m out → 5 − 4.572 = 0.428 m would shrink the strip; floored at
    # 12 ft, so a shallow lot is unchanged from the flat behavior.
    ext_on, _ = _front_ext(5.0, row_to_curb=True)
    ext_off, _ = _front_ext(5.0, row_to_curb=False)
    assert ext_on == pytest.approx(ext_off, rel=1e-6)


def test_row_to_curb_off_leaves_deep_setback_at_flat_strip():
    # The flag gates the change: with it off, a deep-setback frontage stays the
    # flat 12 ft strip (the estimation path must not move when off).
    ext_off, area_off = _front_ext(10.0, row_to_curb=False)
    flat = SIZE_M * DIST_M * SQFT_PER_SQM  # ~1181.1 sqft
    assert ext_off == pytest.approx(flat, rel=2e-3)
    _, area_on = _front_ext(10.0, row_to_curb=True)
    assert area_on > area_off  # the flag, and only the flag, moves the number


# ---------------------------------------------------------------------------
# Pure projection/area helpers
# ---------------------------------------------------------------------------
def test_area_per_pixel_scales_with_scale_factor():
    # A scale-2 image has 4x the pixels, so each pixel covers 1/4 the ground area.
    at_scale_1 = area_per_pixel_sqft(41.26, 20, 1)
    at_scale_2 = area_per_pixel_sqft(41.26, 20, 2)
    assert at_scale_1 == pytest.approx(4 * at_scale_2, rel=1e-9)


def test_geometry_area_of_known_square():
    parcel = utm_to_wgs(square_utm(OMAHA_CX, OMAHA_CY, SIZE_M))
    assert geometry_area_sqft(parcel, CRS) == pytest.approx(SIZE_M * SIZE_M * SQFT_PER_SQM, rel=2e-3)


# ---------------------------------------------------------------------------
# Frame guard (H-3): a parcel larger than the fixed imagery window is measured on
# truncated masks; the pipeline flags it rather than return a confident wrong number.
# ---------------------------------------------------------------------------
_FRAME_KW = dict(center_latitude=CENTER_LAT, center_longitude=CENTER_LON,
                 zoom=20, image_width_px=1280, image_height_px=1280, scale=2)


def test_normal_lot_fits_the_frame():
    parcel = utm_to_wgs(square_utm(OMAHA_CX, OMAHA_CY, 30.0))  # ~30 m, well inside
    assert geometry_exceeds_frame(parcel, **_FRAME_KW) is False


def test_oversized_parcel_exceeds_frame():
    # The frame is ~71.8 m across at zoom 20; a 120 m lot overflows it.
    parcel = utm_to_wgs(square_utm(OMAHA_CX, OMAHA_CY, 120.0))
    assert geometry_exceeds_frame(parcel, **_FRAME_KW) is True