import json
import os
import tempfile
import unittest
from unittest.mock import patch

import embeddings


class FakeResponse:
    def __init__(self, payload):
        self.payload = payload

    def __enter__(self):
        return self

    def __exit__(self, *_):
        return None

    def read(self):
        return json.dumps(self.payload).encode("utf-8")


class TextExtractionTests(unittest.TestCase):
    def write_text(self, suffix, content):
        handle = tempfile.NamedTemporaryFile(suffix=suffix, delete=False)
        handle.close()
        self.addCleanup(lambda: os.path.exists(handle.name) and os.unlink(handle.name))
        with open(handle.name, "w", encoding="utf-8") as stream:
            stream.write(content)
        return handle.name

    def test_extracts_utf8_markdown(self):
        path = self.write_text(".md", "# 退款规则\n\n七日内可申请退款。")
        self.assertEqual(embeddings.extract_text(path, ".md"), "# 退款规则\n\n七日内可申请退款。")

    def test_extracts_utf8_text(self):
        path = self.write_text(".txt", "客服热线：400-123-4567")
        self.assertEqual(embeddings.extract_text(path, ".txt"), "客服热线：400-123-4567")

    def test_rejects_unsupported_extension(self):
        path = self.write_text(".csv", "not supported")
        with self.assertRaises(ValueError):
            embeddings.extract_text(path, ".csv")


class RemoteEmbeddingTests(unittest.TestCase):
    def test_large_input_is_split_into_provider_safe_batches(self):
        texts = [f"chunk-{index}" for index in range(14)]
        batch_sizes = []

        def fake_urlopen(request, timeout):
            self.assertEqual(timeout, 30)
            payload = json.loads(request.data.decode("utf-8"))
            batch_sizes.append(len(payload["input"]))
            return FakeResponse({
                "data": [
                    {"index": index, "embedding": [float(text.split("-")[1])]}
                    for index, text in enumerate(payload["input"])
                ]
            })

        with patch.dict(os.environ, {
            "EMBEDDING_API_URL": "https://embedding.example/v1/embeddings",
            "EMBEDDING_API_KEY": "test-key",
            "EMBEDDING_MODEL": "text-embedding-v4",
            "EMBEDDING_BATCH_SIZE": "10",
        }), patch("embeddings.urllib.request.urlopen", side_effect=fake_urlopen):
            result = embeddings.embed(texts)

        self.assertEqual(batch_sizes, [10, 4])
        self.assertEqual(result, [[float(index)] for index in range(14)])


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