import numpy as np

from ... import config
from ...core import Check, Issue, contexts
from ...core.mesh import loop_polygon_index, polygon_arrays


class UVCheck(Check):
    id = "uvs"
    label = "UVs"
    description = "Every mesh has a UV map and no UV coordinate is negative."
    category = "UVs"
    contexts = contexts.ASSET

    def run(self, ctx):
        for ob in ctx.objects("MESH"):
            me = ob.data
            if not len(me.polygons):
                continue
            if not me.uv_layers:
                yield Issue.for_id(f"{ob.name}: no UV map", ob)
                continue

            _, totals, _ = polygon_arrays(me)
            poly_of_loop = loop_polygon_index(totals)
            for layer in me.uv_layers:
                uv = np.empty(len(me.loops) * 2, dtype=np.float32)
                layer.uv.foreach_get("vector", uv)
                negative = (uv.reshape(-1, 2) < -config.UV_NEGATIVE_TOLERANCE).any(axis=1)
                if negative.any():
                    faces = np.unique(poly_of_loop[negative])
                    yield Issue.for_id(
                        f"{ob.name}: UV map '{layer.name}' has negative UVs on {faces.size} face(s)",
                        ob,
                        elements=faces.tolist(),
                        element_type="FACE",
                    )