from __future__ import annotations

from pathlib import Path
from typing import Callable

from .indexers import (
    build_filename_matched_records,
    build_paired_folder_records,
    build_prefixed_paired_records,
    build_pre_split_records,
    build_stem_paired_records,
    build_xml_annotation_records,
)
from .records import SegSampleRecord


def _build_bus_uclm(root: Path) -> list[SegSampleRecord]:
    return build_paired_folder_records(
        dataset_name="BUS-UCLM",
        image_dir=root / "images",
        mask_dir=root / "masks",
    )


def _build_tg3k(root: Path) -> list[SegSampleRecord]:
    return build_paired_folder_records(
        dataset_name="TG3K",
        image_dir=root / "thyroid-image",
        mask_dir=root / "thyroid-mask",
    )


def _build_tn3k(root: Path) -> list[SegSampleRecord]:
    return build_pre_split_records(
        dataset_name="TN3K",
        train_image_dir=root / "trainval-image",
        train_mask_dir=root / "trainval-mask",
        test_image_dir=root / "test-image",
        test_mask_dir=root / "test-mask",
    )


def _build_otu_2d(root: Path) -> list[SegSampleRecord]:
    return build_stem_paired_records(
        dataset_name="OTU_2d",
        image_dir=root / "images",
        mask_dir=root / "annotations",
    )


def _build_busi(root: Path) -> list[SegSampleRecord]:
    base = root / "Dataset_BUSI_with_GT"
    records: list[SegSampleRecord] = []
    for class_name in ["benign", "malignant", "normal"]:
        class_dir = base / class_name
        records.extend(
            build_filename_matched_records(
                dataset_name="BUSI",
                folder=class_dir,
                class_name=class_name,
            )
        )
    return records


def _build_bus_bra(root: Path) -> list[SegSampleRecord]:
    image_dir = root / "BUSBRA" / "BUSBRA" / "Images"
    mask_dir = root / "BUSBRA" / "BUSBRA" / "Masks"
    return build_prefixed_paired_records(
        dataset_name="BUS-BRA",
        image_dir=image_dir,
        mask_dir=mask_dir,
        image_prefix_to_strip="bus_",
        mask_prefix_to_strip="mask_",
    )


def _build_bus_uc(root: Path) -> list[SegSampleRecord]:
    base = root / "BUS_UC" / "BUS_UC"
    records: list[SegSampleRecord] = []

    records.extend(
        build_paired_folder_records(
            dataset_name="BUS_UC",
            image_dir=base / "All" / "images",
            mask_dir=base / "All" / "masks",
            split="all",
            class_name="all",
        )
    )
    records.extend(
        build_paired_folder_records(
            dataset_name="BUS_UC",
            image_dir=base / "Benign" / "images",
            mask_dir=base / "Benign" / "masks",
            class_name="benign",
        )
    )
    records.extend(
        build_paired_folder_records(
            dataset_name="BUS_UC",
            image_dir=base / "Malignant" / "images",
            mask_dir=base / "Malignant" / "masks",
            class_name="malignant",
        )
    )
    return records


def _build_ccaui(root: Path) -> list[SegSampleRecord]:
    base = root / "Common Carotid Artery Ultrasound Images"
    return build_paired_folder_records(
        dataset_name="CCAUI",
        image_dir=base / "US images",
        mask_dir=base / "Expert mask images",
    )


def _build_ddti(root: Path) -> list[SegSampleRecord]:
    return build_xml_annotation_records(
        dataset_name="DDTI",
        root=root,
    )


DATASET_REGISTRY: dict[str, Callable[[Path], list[SegSampleRecord]]] = {
    "BUS-UCLM": _build_bus_uclm,
    "TG3K": _build_tg3k,
    "TN3K": _build_tn3k,
    "OTU_2d": _build_otu_2d,
    "BUSI": _build_busi,
    "BUS-BRA": _build_bus_bra,
    "BUS_UC": _build_bus_uc,
    "CCAUI": _build_ccaui,
    "DDTI": _build_ddti,
}


def build_dataset_index(dataset_name: str, root: str | Path) -> list[SegSampleRecord]:
    builder = DATASET_REGISTRY.get(dataset_name)
    if builder is None:
        raise ValueError(
            f"Unsupported dataset '{dataset_name}'. Expected one of: {', '.join(DATASET_REGISTRY)}."
        )
    root = Path(root)
    if not root.exists():
        raise FileNotFoundError(f"Dataset root not found: {root}")
    return builder(root)


__all__ = ["DATASET_REGISTRY", "build_dataset_index"]