from __future__ import annotations

import argparse
from collections import Counter
from pathlib import Path
import sys

PROJECT_ROOT = Path(__file__).resolve().parent.parent
if str(PROJECT_ROOT) not in sys.path:
    sys.path.insert(0, str(PROJECT_ROOT))

from step_editor.model import StepModel

DEFAULT_MODEL = PROJECT_ROOT / "assets" / "models" / "cube_10mm.step"


def _edge_length(model: StepModel, edge_id: int) -> float:
    return float(model.edge_info(edge_id).get("length", 0.0))


def _line_edge_ids_near_length(model: StepModel, length: float, tolerance: float) -> list[int]:
    edge_ids: list[int] = []
    for edge_id in range(len(model.edges)):
        info = model.edge_info(edge_id)
        if info.get("curve") != "line":
            continue
        if abs(float(info.get("length", 0.0)) - length) <= tolerance:
            edge_ids.append(edge_id)
    return edge_ids


def _length_distribution(model: StepModel) -> dict[float, int]:
    counts = Counter(round(_edge_length(model, edge_id), 6) for edge_id in range(len(model.edges)))
    return dict(sorted(counts.items()))


def _count_near(values: list[float], target: float, tolerance: float) -> int:
    return sum(1 for value in values if abs(value - target) <= tolerance)


def _assert_cube_edge_intent_geometry(
    *,
    source_length: float,
    target_length: float,
    strategy: str,
    anchor: str,
    lengths: list[float],
    tolerance: float,
) -> None:
    target_count = _count_near(lengths, target_length, tolerance)
    source_count = _count_near(lengths, source_length, tolerance)
    delta = abs(target_length - source_length)
    effective_anchor = "keep-start" if anchor == "auto" else anchor
    if strategy == "local-edge-only-deform":
        if target_count != 1:
            raise SystemExit(
                "local Edge deformation should only make the selected Edge reach the target length; "
                f"target_count={target_count}, lengths={_length_distribution_from_values(lengths)}"
            )
        if effective_anchor == "center":
            expected_slanted = (source_length * source_length + (delta * 0.5) * (delta * 0.5)) ** 0.5
            slanted_count = _count_near(lengths, expected_slanted, tolerance)
            if source_count != 7 or slanted_count != 4:
                raise SystemExit(
                    "center-anchored local Edge deformation should move both endpoints equally; "
                    f"source_count={source_count}, slanted_count={slanted_count}, "
                    f"expected_slanted={expected_slanted:g}, lengths={_length_distribution_from_values(lengths)}"
                )
        else:
            expected_slanted = (source_length * source_length + delta * delta) ** 0.5
            slanted_count = _count_near(lengths, expected_slanted, tolerance)
            if source_count != 9 or slanted_count != 2:
                raise SystemExit(
                    "one-end anchored local Edge deformation should move only the selected Edge endpoint; "
                    f"source_count={source_count}, slanted_count={slanted_count}, "
                    f"expected_slanted={expected_slanted:g}, lengths={_length_distribution_from_values(lengths)}"
                )
    elif strategy in {"move-edge-end-plane-by-push-pull", "scale-owning-shape-from-edge"}:
        if target_count != 4 or source_count != 8:
            raise SystemExit(
                f"{strategy} should resize the whole cube span in the selected Edge direction; "
                f"target_count={target_count}, source_count={source_count}, "
                f"lengths={_length_distribution_from_values(lengths)}"
            )


def _length_distribution_from_values(values: list[float]) -> dict[float, int]:
    counts = Counter(round(value, 6) for value in values)
    return dict(sorted(counts.items()))


def main() -> int:
    parser = argparse.ArgumentParser(description="Verify cube edge-length resize semantics.")
    parser.add_argument("model", nargs="?", default=str(DEFAULT_MODEL), help="STEP model path.")
    parser.add_argument("--source-length", type=float, default=10.0, help="Current line edge length to search for.")
    parser.add_argument("--target-length", type=float, default=15.0, help="Target edge length to apply.")
    parser.add_argument("--anchor", default="keep-start", choices=["auto", "center", "keep-start", "keep-end"])
    parser.add_argument(
        "--strategy",
        default="local-edge-only-deform",
        choices=[
            "auto",
            "local-edge-only-deform",
            "move-edge-end-plane-by-push-pull",
            "scale-owning-shape-from-edge",
        ],
        help="Requested Edge length edit semantics.",
    )
    parser.add_argument("--expect-strategy", default="", help="Expected resolved resize strategy.")
    parser.add_argument("--tolerance", type=float, default=1e-5, help="Allowed target length error.")
    args = parser.parse_args()

    model = StepModel.load(Path(args.model))
    edge_ids = _line_edge_ids_near_length(model, args.source_length, args.tolerance)
    if not edge_ids:
        raise SystemExit(f"no line edge near source length {args.source_length:g}")

    edge_id = edge_ids[0]
    before = model.stats()
    plan = model.general_edge_length_plan(
        edge_id,
        args.target_length,
        anchor_mode=args.anchor,
        strategy_mode=args.strategy,
    )
    strategy = str(plan.get("resize_strategy", ""))
    expected_strategy = args.expect_strategy or args.strategy
    if expected_strategy == "auto":
        expected_strategy = strategy
    if strategy != expected_strategy:
        raise SystemExit(f"expected {expected_strategy}, got {strategy or '<none>'}")

    result = model.resize_general_edge_length(
        edge_id,
        args.target_length,
        anchor_mode=args.anchor,
        strategy_mode=args.strategy,
    )
    after = model.stats()
    lengths = [_edge_length(model, item) for item in range(len(model.edges))]
    nearest = min(lengths, key=lambda value: abs(value - args.target_length))
    error = abs(nearest - args.target_length)
    if error > args.tolerance:
        raise SystemExit(f"target length check failed: nearest={nearest:g}, error={error:g}")
    if (
        Path(args.model).resolve() == DEFAULT_MODEL.resolve()
        and strategy == "local-edge-only-deform"
        and (after.faces != before.faces or after.edges != before.edges)
    ):
        raise SystemExit(
            "cube local Edge deformation should not split faces/edges; "
            f"before faces/edges={before.faces}/{before.edges}, after={after.faces}/{after.edges}"
        )
    if Path(args.model).resolve() == DEFAULT_MODEL.resolve():
        _assert_cube_edge_intent_geometry(
            source_length=args.source_length,
            target_length=args.target_length,
            strategy=strategy,
            anchor=args.anchor,
            lengths=lengths,
            tolerance=max(args.tolerance, 1e-5),
        )

    print(f"model={Path(args.model)}")
    print(f"edge_id={edge_id}")
    print(f"requested_strategy={args.strategy}")
    print(f"strategy={strategy}")
    print(f"anchor_mode={args.anchor}")
    print(f"start_move={plan.get('local_edge_deform_start_move')}")
    print(f"end_move={plan.get('local_edge_deform_end_move')}")
    print(f"before_faces={before.faces} before_edges={before.edges}")
    print(f"after_faces={after.faces} after_edges={after.edges}")
    print(f"topology_stable={after.faces == before.faces and after.edges == before.edges}")
    print(f"nearest_length={nearest:.6f} target_error={error:.6g}")
    print(f"length_distribution={_length_distribution(model)}")
    print(result.encode("ascii", "backslashreplace").decode("ascii"))
    return 0


if __name__ == "__main__":
    raise SystemExit(main())