"""Dataset loader tests."""

from __future__ import annotations

import json
import tempfile
import unittest
from pathlib import Path

from zsgdp.benchmarks.datasets import (
    DatasetDocument,
    get_dataset_loader,
    iter_dataset,
    list_dataset_loaders,
    register_dataset_loader,
)


class TestDatasetRegistry(unittest.TestCase):
    def test_built_in_loaders_registered(self):
        loaders = list_dataset_loaders()
        self.assertIn("custom_folder", loaders)
        self.assertIn("omnidocbench", loaders)
        self.assertIn("doclaynet", loaders)

    def test_custom_alias_resolves_to_custom_folder(self):
        loader_default = get_dataset_loader("default")
        loader_alias = get_dataset_loader("custom")
        loader_canonical = get_dataset_loader("custom_folder")
        self.assertIs(loader_default, loader_canonical)
        self.assertIs(loader_alias, loader_canonical)

    def test_unknown_loader_raises(self):
        with self.assertRaises(KeyError):
            get_dataset_loader("not_a_real_dataset")


class TestCustomFolderLoader(unittest.TestCase):
    def test_yields_files_with_no_ground_truth(self):
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            (root / "a.md").write_text("# A\n")
            (root / "b.md").write_text("# B\n")
            (root / "subdir").mkdir()
            (root / "subdir" / "ignored.md").write_text("# nope\n")

            documents = list(iter_dataset("custom_folder", root))

            ids = sorted(document.doc_id for document in documents)
            self.assertEqual(ids, ["a", "b"])
            for document in documents:
                self.assertIsNone(document.ground_truth)
                self.assertEqual(document.dataset_id, "custom_folder")
                self.assertTrue(document.path.exists())

    def test_missing_root_raises(self):
        with self.assertRaises(FileNotFoundError):
            list(iter_dataset("custom_folder", "/tmp/this-path-should-not-exist-zsgdp"))


class TestOmniDocBenchLoader(unittest.TestCase):
    def test_pairs_pdf_with_sibling_json(self):
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            (root / "doc1.pdf").write_bytes(b"%PDF-1.4\n%%EOF\n")
            (root / "doc1.json").write_text(json.dumps({"reading_order": ["e1", "e2"]}))
            (root / "doc2.pdf").write_bytes(b"%PDF-1.4\n%%EOF\n")  # no GT

            documents = list(iter_dataset("omnidocbench", root))

        by_id = {document.doc_id: document for document in documents}
        self.assertEqual(set(by_id), {"doc1", "doc2"})

        self.assertIsNotNone(by_id["doc1"].ground_truth)
        self.assertEqual(by_id["doc1"].ground_truth["reading_order"], ["e1", "e2"])
        self.assertTrue(by_id["doc1"].metadata["has_ground_truth"])

        self.assertIsNone(by_id["doc2"].ground_truth)
        self.assertFalse(by_id["doc2"].metadata["has_ground_truth"])

    def test_no_pdfs_raises(self):
        with tempfile.TemporaryDirectory() as tmp:
            with self.assertRaises(FileNotFoundError):
                list(iter_dataset("omnidocbench", tmp))


class TestDocLayNetLoader(unittest.TestCase):
    def test_yields_one_document_per_image_with_filtered_annotations(self):
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            (root / "page1.png").write_bytes(b"\x89PNG\r\n\x1a\n")
            (root / "page2.png").write_bytes(b"\x89PNG\r\n\x1a\n")
            (root / "annotations.json").write_text(
                json.dumps(
                    {
                        "images": [
                            {"id": 1, "file_name": "page1.png", "width": 800, "height": 1100},
                            {"id": 2, "file_name": "page2.png", "width": 800, "height": 1100},
                        ],
                        "annotations": [
                            {"id": 10, "image_id": 1, "category_id": 1, "bbox": [0, 0, 100, 50]},
                            {"id": 11, "image_id": 1, "category_id": 2, "bbox": [0, 60, 100, 50]},
                            {"id": 12, "image_id": 2, "category_id": 1, "bbox": [0, 0, 100, 50]},
                        ],
                        "categories": [
                            {"id": 1, "name": "Title"},
                            {"id": 2, "name": "Text"},
                        ],
                    }
                )
            )

            documents = list(iter_dataset("doclaynet", root))

        by_id = {document.doc_id: document for document in documents}
        self.assertEqual(set(by_id), {"page1.png", "page2.png"})

        self.assertEqual(len(by_id["page1.png"].ground_truth["annotations"]), 2)
        self.assertEqual(len(by_id["page2.png"].ground_truth["annotations"]), 1)
        self.assertEqual(by_id["page1.png"].ground_truth["categories"][1]["name"], "Title")

    def test_missing_annotations_raises(self):
        with tempfile.TemporaryDirectory() as tmp:
            root = Path(tmp)
            (root / "page1.png").write_bytes(b"\x89PNG\r\n\x1a\n")
            with self.assertRaises(FileNotFoundError):
                list(iter_dataset("doclaynet", root))


class TestRegisterDatasetLoader(unittest.TestCase):
    def test_register_and_use_custom_loader(self):
        marker = []

        def fake_loader(root: Path):
            marker.append(root)
            yield DatasetDocument(dataset_id="fake", doc_id="x", path=root)

        register_dataset_loader("zsgdp_test_fake", fake_loader)
        try:
            documents = list(iter_dataset("zsgdp_test_fake", Path("/tmp/whatever")))
        finally:
            from zsgdp.benchmarks.datasets import _LOADERS

            _LOADERS.pop("zsgdp_test_fake", None)

        self.assertEqual(len(documents), 1)
        self.assertEqual(documents[0].dataset_id, "fake")
        self.assertEqual(marker, [Path("/tmp/whatever")])


if __name__ == "__main__":
    unittest.main()