from __future__ import annotations

from pathlib import Path
from typing import Any

import pandas as pd


def _build_transformer(source_crs: Any, target_crs: str | None):
    if not source_crs or not target_crs:
        return None

    try:
        from pyproj import CRS, Transformer
    except Exception:
        return None

    try:
        source = CRS.from_user_input(source_crs)
        target = CRS.from_user_input(target_crs)
    except Exception:
        return None

    if source == target:
        return None

    try:
        return Transformer.from_crs(source, target, always_xy=True)
    except Exception:
        return None


def _field_name(field: Any) -> str:
    if hasattr(field, "name"):
        return str(getattr(field, "name") or "")
    if isinstance(field, (list, tuple)) and field:
        return str(field[0] or "")
    return str(field or "")


def _iter_features_pyshp(shapefile_path: Path, *, target_crs: str | None) -> list[tuple[dict[str, Any], Any]]:
    import shapefile
    from shapely.geometry import shape
    from shapely.ops import transform as shapely_transform

    shp_path = shapefile_path.with_suffix(".shp")
    shx_path = shapefile_path.with_suffix(".shx")
    dbf_path = shapefile_path.with_suffix(".dbf")

    def _describe_sidecars() -> str:
        parts: list[str] = []
        for candidate in (shp_path, shx_path, dbf_path, shapefile_path.with_suffix(".prj"), shapefile_path.with_suffix(".cpg")):
            if candidate.exists():
                try:
                    parts.append(f"{candidate.name}={candidate.stat().st_size}")
                except Exception:
                    parts.append(f"{candidate.name}=present")
            else:
                parts.append(f"{candidate.name}=missing")
        return ", ".join(parts)

    if not shp_path.exists():
        raise FileNotFoundError(f"Shapefile nao encontrado: {shp_path}")

    handles = []
    reader = None
    try:
        shp_handle = open(shp_path, "rb")
        handles.append(shp_handle)
        shx_handle = open(shx_path, "rb") if shx_path.exists() else None
        if shx_handle is not None:
            handles.append(shx_handle)
        dbf_handle = open(dbf_path, "rb") if dbf_path.exists() else None
        if dbf_handle is not None:
            handles.append(dbf_handle)

        reader = shapefile.Reader(
            shp=shp_handle,
            shx=shx_handle,
            dbf=dbf_handle,
            encoding="utf-8",
            encodingErrors="replace",
        )
        field_names = [_field_name(field) for field in reader.fields[1:]]
        source_crs = None
        prj_path = shapefile_path.with_suffix(".prj")
        if prj_path.exists():
            try:
                source_crs = prj_path.read_text(encoding="utf-8", errors="replace")
            except Exception:
                source_crs = prj_path.read_text(errors="replace")
        transformer = _build_transformer(source_crs, target_crs)

        features: list[tuple[dict[str, Any], Any]] = []
        record_errors: list[str] = []
        for index, shape_record in enumerate(reader.iterShapeRecords()):
            try:
                values = list(shape_record.record)
                properties = {
                    field_name: values[field_index] if field_index < len(values) else None
                    for field_index, field_name in enumerate(field_names)
                }
                geometry_raw = getattr(shape_record.shape, "__geo_interface__", None)
                geometry = None
                if geometry_raw and geometry_raw.get("coordinates"):
                    geometry = shape(geometry_raw)
                    if transformer is not None:
                        geometry = shapely_transform(transformer.transform, geometry)
                features.append((properties, geometry))
            except Exception as exc:
                if len(record_errors) < 5:
                    record_errors.append(f"registro {index}: {exc!r}")
                continue

        if not features and record_errors:
            detalhe = "; ".join(record_errors)
            raise RuntimeError(f"nenhum registro legivel via pyshp ({detalhe})")
        return features
    except Exception as exc:
        raise RuntimeError(
            f"pyshp falhou para {shapefile_path.name}: {exc!r}; arquivos: {_describe_sidecars()}"
        ) from exc
    finally:
        try:
            if reader is not None:
                reader.close()
        except Exception:
            pass
        for handle in handles:
            try:
                handle.close()
            except Exception:
                pass


def _iter_features_fiona(shapefile_path: Path, *, target_crs: str | None) -> list[tuple[dict[str, Any], Any]]:
    import fiona
    from shapely.geometry import shape
    from shapely.ops import transform as shapely_transform

    features: list[tuple[dict[str, Any], Any]] = []
    with fiona.open(shapefile_path) as source:
        transformer = _build_transformer(source.crs_wkt or source.crs, target_crs)
        for feature in source:
            properties = dict(feature.get("properties") or {})
            geometry_raw = feature.get("geometry")
            geometry = None
            if geometry_raw:
                geometry = shape(geometry_raw)
                if transformer is not None:
                    geometry = shapely_transform(transformer.transform, geometry)
            features.append((properties, geometry))
    return features


def _load_features(shapefile_path: Path, *, target_crs: str | None = "EPSG:4326") -> list[tuple[dict[str, Any], Any]]:
    pyshp_error = None
    try:
        return _iter_features_pyshp(shapefile_path, target_crs=target_crs)
    except Exception as exc:
        pyshp_error = exc

    try:
        return _iter_features_fiona(shapefile_path, target_crs=target_crs)
    except Exception:
        if pyshp_error is not None:
            raise pyshp_error
        raise


def load_vector_dataframe(shapefile_path: str | Path, *, target_crs: str | None = "EPSG:4326") -> pd.DataFrame:
    path = Path(shapefile_path).expanduser().resolve()
    if not path.exists():
        raise FileNotFoundError(f"Shapefile nao encontrado: {path}")

    rows: list[dict[str, Any]] = []
    for properties, geometry in _load_features(path, target_crs=target_crs):
        row = dict(properties)
        row["geometry"] = geometry
        rows.append(row)

    return pd.DataFrame(rows)


def load_vector_geojson(
    shapefile_path: str | Path,
    *,
    target_crs: str | None = "EPSG:4326",
    property_fields: tuple[str, ...] | list[str] | None = None,
    simplify_tolerance: float = 0.0,
) -> dict[str, Any]:
    from shapely.geometry import mapping

    path = Path(shapefile_path).expanduser().resolve()
    if not path.exists():
        raise FileNotFoundError(f"Shapefile nao encontrado: {path}")

    feature_collection: dict[str, Any] = {
        "type": "FeatureCollection",
        "features": [],
    }

    wanted_fields = tuple(str(field).strip() for field in (property_fields or ()) if str(field).strip())
    for properties_raw, geometry in _load_features(path, target_crs=target_crs):
        if geometry is None:
            continue

        if simplify_tolerance:
            geometry = geometry.simplify(float(simplify_tolerance), preserve_topology=True)

        properties = (
            {field: properties_raw.get(field) for field in wanted_fields if field in properties_raw}
            if wanted_fields
            else dict(properties_raw)
        )
        feature_collection["features"].append(
            {
                "type": "Feature",
                "properties": properties,
                "geometry": mapping(geometry),
            }
        )

    return feature_collection


def load_attribute_records(
    shapefile_path: str | Path,
    *,
    property_fields: tuple[str, ...] | list[str] | None = None,
) -> list[dict[str, Any]]:
    path = Path(shapefile_path).expanduser().resolve()
    dbf_path = path.with_suffix(".dbf")
    if not dbf_path.exists():
        raise FileNotFoundError(f"DBF nao encontrado: {dbf_path}")

    wanted_fields = tuple(str(field).strip() for field in (property_fields or ()) if str(field).strip())

    try:
        import shapefile
    except Exception:
        records: list[dict[str, Any]] = []
        for properties, _ in _load_features(path, target_crs=None):
            if wanted_fields:
                records.append({field: properties.get(field) for field in wanted_fields if field in properties})
            else:
                records.append(dict(properties))
        return records

    with open(dbf_path, "rb") as dbf_handle:
        reader = shapefile.Reader(dbf=dbf_handle, encoding="utf-8", encodingErrors="replace")
        field_names = [_field_name(field) for field in reader.fields[1:]]
        records: list[dict[str, Any]] = []
        for record in reader.iterRecords():
            values = list(record)
            row = {
                field_name: values[index] if index < len(values) else None
                for index, field_name in enumerate(field_names)
            }
            if wanted_fields:
                row = {field: row.get(field) for field in wanted_fields if field in row}
            records.append(row)
        return records