import importlib
import os
import shutil
import tempfile
import unittest

import httpx


class TestDocPreviewTruncation(unittest.IsolatedAsyncioTestCase):
    async def asyncSetUp(self):
        self._old_env = dict(os.environ)
        self.tmp = tempfile.mkdtemp(prefix="llm-council-docprev-")
        os.environ["DOCS_DIR"] = self.tmp
        os.environ["MAX_DOC_BYTES"] = "1000000"
        os.environ["MAX_DOC_PREVIEW_CHARS"] = "10"

        import backend.config as config
        import backend.documents as documents
        import backend.main as main

        importlib.reload(config)
        importlib.reload(documents)
        self.main = importlib.reload(main)

        self.client = httpx.AsyncClient(
            transport=httpx.ASGITransport(app=self.main.app),
            base_url="http://test",
        )

        # Create a conversation
        resp = await self.client.post("/api/conversations", json={})
        resp.raise_for_status()
        self.conversation_id = resp.json()["id"]

        # Upload a long doc
        files = {"file": ("long.md", b"0123456789ABCDEFGHIJ", "text/markdown")}
        up = await self.client.post(
            f"/api/conversations/{self.conversation_id}/documents",
            files=files,
        )
        up.raise_for_status()
        self.doc_id = up.json()["id"]

    async def asyncTearDown(self):
        await self.client.aclose()
        os.environ.clear()
        os.environ.update(self._old_env)
        shutil.rmtree(self.tmp, ignore_errors=True)

    async def test_preview_truncates(self):
        resp = await self.client.get(
            f"/api/conversations/{self.conversation_id}/documents/{self.doc_id}"
        )
        self.assertEqual(resp.status_code, 200)
        content = resp.json()["content"]
        self.assertEqual(len(content), 10)
        self.assertTrue(content.endswith("..."))