"""Tests for DefaultFileChunker."""

import asyncio
import os
import tempfile

from reme.components.file_chunker import DefaultFileChunker
from reme.utils.wikilink_handler import WikilinkHandler

# Add parent path for import


def test_parse_empty_file():
    """Test parsing an empty file."""

    async def run():
        with tempfile.NamedTemporaryFile(mode="w", delete=False, suffix=".txt") as f:
            temp_path = f.name

        try:
            chunker = DefaultFileChunker()
            file_node, chunks = await chunker.chunk(temp_path)
            assert file_node.path == temp_path
            assert len(chunks) == 0
            print("✓ test_parse_empty_file passed")
        finally:
            os.unlink(temp_path)

    asyncio.run(run())


def test_parse_small_file():
    """Test parsing a file smaller than chunk size."""

    async def run():
        content = "Hello World\nThis is a test\nLine 3"
        with tempfile.NamedTemporaryFile(mode="w", delete=False, suffix=".txt") as f:
            f.write(content)
            temp_path = f.name

        try:
            chunker = DefaultFileChunker(chunk_byte_size=10000)
            _, chunks = await chunker.chunk(temp_path)
            assert len(chunks) == 1
            assert chunks[0].start_line == 1
            assert chunks[0].end_line == 3
            assert chunks[0].text == content
            print("✓ test_parse_small_file passed")
        finally:
            os.unlink(temp_path)

    asyncio.run(run())


def test_parse_chunked_file():
    """Test parsing a file that requires multiple chunks."""

    async def run():
        # Create content larger than chunk size
        lines = ["A" * 100 for _ in range(200)]  # ~20200 bytes
        content = "\n".join(lines)
        with tempfile.NamedTemporaryFile(mode="w", delete=False, suffix=".txt") as f:
            f.write(content)
            temp_path = f.name

        try:
            chunker = DefaultFileChunker(chunk_byte_size=5000, overlap_byte_size=100)
            _, chunks = await chunker.chunk(temp_path)
            assert len(chunks) > 1, f"Expected multiple chunks, got {len(chunks)}"
            # Verify overlap by checking that consecutive chunks share some content
            print(f"  Created {len(chunks)} chunks")
            print("✓ test_parse_chunked_file passed")
        finally:
            os.unlink(temp_path)

    asyncio.run(run())


def test_parse_with_custom_encoding():
    """Test parsing a file with different encodings."""

    async def run():
        content = "你好世界\n测试内容"
        with tempfile.NamedTemporaryFile(mode="w", delete=False, suffix=".txt", encoding="utf-8") as f:
            f.write(content)
            temp_path = f.name

        try:
            chunker = DefaultFileChunker(encoding="utf-8")
            _, chunks = await chunker.chunk(temp_path)
            assert len(chunks) >= 1
            assert "你好世界" in chunks[0].text
            print("✓ test_parse_with_custom_encoding passed")
        finally:
            os.unlink(temp_path)

    asyncio.run(run())


def test_invalid_encoding_policy_is_validated():
    """Reject misspelled policies instead of silently changing decoding behavior."""
    try:
        DefaultFileChunker(invalid_encoding_policy="ignore")
    except ValueError as exc:
        assert "invalid_encoding_policy" in str(exc)
    else:
        raise AssertionError("invalid encoding policy must be rejected")


def test_constructor_preserves_positional_arguments():
    """New decoding options must not reinterpret the established positional API."""
    chunker = DefaultFileChunker("utf-8", 5000, 100)

    assert chunker.encoding == "utf-8"
    assert chunker.chunk_byte_size == 5000
    assert chunker.overlap_byte_size == 100


def test_newlines_are_normalized_before_chunking():
    """Binary reads retain the universal-newline behavior of the old text reader."""

    async def run():
        with tempfile.NamedTemporaryFile(delete=False, suffix=".txt") as f:
            f.write(b"alpha\r\nbeta\rgamma\n")
            temp_path = f.name

        try:
            chunker = DefaultFileChunker()
            _, original_chunks = await chunker.chunk(temp_path)
            with open(temp_path, "wb") as f:
                f.write(b"alpha\nbeta\ngamma\n")
            _, normalized_chunks = await chunker.chunk(temp_path)

            assert [chunk.text for chunk in original_chunks] == ["alpha\nbeta\ngamma\n"]
            assert [chunk.id for chunk in original_chunks] == [chunk.id for chunk in normalized_chunks]
        finally:
            os.unlink(temp_path)

    asyncio.run(run())


def test_ascii_replacement_remains_encodable():
    """Replacement mode must survive byte-based chunking with a single-byte codec."""

    async def run():
        source = b"valid\xffinvalid"
        with tempfile.NamedTemporaryFile(delete=False, suffix=".txt") as f:
            f.write(source)
            temp_path = f.name

        try:
            _, chunks = await DefaultFileChunker(encoding="ascii").chunk(temp_path)

            assert [chunk.text for chunk in chunks] == ["valid?invalid"]
            with open(temp_path, "rb") as f:
                assert f.read() == source
        finally:
            os.unlink(temp_path)

    asyncio.run(run())


def test_parse_links_bare():
    """Bare wikilink: [[target]]."""
    links = WikilinkHandler.extract_links("see [[note]]", "src.md")
    assert len(links) == 1
    link = links[0]
    assert link.source_path == "src.md"
    assert link.target_path == "note"
    assert link.target_anchor is None
    print("✓ test_parse_links_bare passed")


def test_parse_links_with_anchor():
    """Wikilink with anchor: [[target#anchor]]."""
    links = WikilinkHandler.extract_links("see [[note#section A]]", "src.md")
    assert len(links) == 1
    assert links[0].target_path == "note"
    assert links[0].target_anchor == "section A"
    print("✓ test_parse_links_with_anchor passed")


def test_parse_links_alias_dropped():
    """Alias after '|' is consumed but not captured as anchor."""
    links = WikilinkHandler.extract_links("see [[note|display text]]", "src.md")
    assert len(links) == 1
    assert links[0].target_path == "note"
    assert links[0].target_anchor is None
    print("✓ test_parse_links_alias_dropped passed")


def test_parse_links_anchor_and_alias():
    """[[target#anchor|alias]] — anchor captured, alias dropped."""
    links = WikilinkHandler.extract_links("see [[note#sec|disp]]", "src.md")
    assert len(links) == 1
    assert links[0].target_path == "note"
    assert links[0].target_anchor == "sec"
    print("✓ test_parse_links_anchor_and_alias passed")


def test_parse_links_ignores_legacy_relation_wrappers():
    """Legacy relation text remains compatible as ordinary wikilinks."""
    links = WikilinkHandler.extract_links(
        "related:: [[a]]\n- related:: [[b]]\n[related:: [[c#section]]]",
        "src.md",
    )
    assert [(link.target_path, link.target_anchor) for link in links] == [
        ("a", None),
        ("b", None),
        ("c", "section"),
    ]
    assert all(link.predicate is None for link in links)


def test_parse_links_multiple_on_one_line():
    """Multiple bare wikilinks on the same line are all captured."""
    links = WikilinkHandler.extract_links("see [[x]] and [[y#h]]", "src.md")
    assert [(link.target_path, link.target_anchor) for link in links] == [
        ("x", None),
        ("y", "h"),
    ]
    print("✓ test_parse_links_multiple_on_one_line passed")


def test_parse_wikilink_line_ranges():
    """Workspace paths and supported line-range forms create FileLink edges."""
    links = WikilinkHandler.extract_links(
        "[[daily/2026-06-20/session.md]] [[notes/example.md#L9]] "
        + "[[notes/example.md#L9-L10]] [[notes/example.md#L9-L10,L15-L20]]",
        "src.md",
    )
    assert [(link.target_path, link.target_anchor) for link in links] == [
        ("daily/2026-06-20/session.md", None),
        ("notes/example.md", "L9"),
        ("notes/example.md", "L9-L10"),
        ("notes/example.md", "L9-L10,L15-L20"),
    ]


def test_parse_markdown_links_are_ignored():
    """Ordinary Markdown links do not create FileLink edges."""
    links = WikilinkHandler.extract_links(
        "[plain](../wiki/a.md) [section](../wiki/a.md#section) [ranges](../wiki/b.md#L9-L10,L15-L20)",
        "daily/note.md",
    )
    assert not links


def test_parse_links_no_match():
    """Strings without [[]] yield no links, even if '::' appears."""
    assert len(WikilinkHandler.extract_links("no link here :: foo", "src.md")) == 0
    assert len(WikilinkHandler.extract_links("plain text without brackets", "src.md")) == 0
    assert len(WikilinkHandler.extract_links("", "src.md")) == 0
    print("✓ test_parse_links_no_match passed")


def test_parse_links_in_file():
    """Integration: parse() populates FileNode.links from file content."""

    async def run():
        content = (
            "---\n"
            "name: demo\n"
            "---\n"
            "\n"
            "Intro paragraph with [[alpha]] and [[beta#h2]].\n"
            "author:: [[Alice]]\n"
            "[ref:: [[paper#chapter 1]]]\n"
        )
        with tempfile.NamedTemporaryFile(mode="w", delete=False, suffix=".md") as f:
            f.write(content)
            temp_path = f.name

        try:
            chunker = DefaultFileChunker()
            file_node, _ = await chunker.chunk(temp_path)
            pairs = {(link.target_path, link.target_anchor) for link in file_node.links}
            assert pairs == {("alpha", None), ("beta", "h2"), ("Alice", None), ("paper", "chapter 1")}
            assert all(link.source_path == file_node.path for link in file_node.links)
            print("✓ test_parse_links_in_file passed")
        finally:
            os.unlink(temp_path)

    asyncio.run(run())


def test_parse_links_empty_when_no_content():
    """Empty file and front-matter-only file both yield no links."""

    async def run():
        # Empty file
        with tempfile.NamedTemporaryFile(mode="w", delete=False, suffix=".md") as f:
            empty_path = f.name
        # Front-matter-only file
        with tempfile.NamedTemporaryFile(mode="w", delete=False, suffix=".md") as f:
            f.write("---\nname: x\n---\n")
            fm_only_path = f.name

        try:
            chunker = DefaultFileChunker()
            node1, _ = await chunker.chunk(empty_path)
            node2, _ = await chunker.chunk(fm_only_path)
            assert node1.links == []
            assert node2.links == []
            print("✓ test_parse_links_empty_when_no_content passed")
        finally:
            os.unlink(empty_path)
            os.unlink(fm_only_path)

    asyncio.run(run())


def test_chunk_does_not_split_wikilink_at_boundary():
    """A wikilink straddling the chunk_byte_size boundary should be retreated to its start."""

    async def run():
        # Pre-link filler is 90 bytes, link itself is 19 bytes ("[[a-very-long-target]]"=22).
        # With chunk_byte_size=100, the boundary lands inside the link.
        prefix = "x" * 90
        link = "[[a-very-long-target]]"  # 22 bytes
        suffix = "y" * 90
        content = f"{prefix}{link}{suffix}"
        with tempfile.NamedTemporaryFile(mode="w", delete=False, suffix=".md") as f:
            f.write(content)
            temp_path = f.name

        try:
            chunker = DefaultFileChunker(chunk_byte_size=100, overlap_byte_size=10)
            _, chunks = await chunker.chunk(temp_path)
            # The first chunk must NOT contain a partial link.
            first = chunks[0].text
            assert "[[" not in first or "]]" in first, f"first chunk has dangling '[[': {first!r}"
            # And the link should appear intact in some chunk.
            assert any(link in c.text for c in chunks), "link was split across all chunks"
            print("✓ test_chunk_does_not_split_wikilink_at_boundary passed")
        finally:
            os.unlink(temp_path)

    asyncio.run(run())


def test_chunk_does_not_split_wikilink_in_overlap():
    """A wikilink landing inside the overlap region should be advanced past."""

    async def run():
        # 200-byte content, chunk=100, overlap=20. First chunk ends near byte 100,
        # next start = 80. Place a link straddling byte 80 to land in the overlap.
        prefix = "a" * 75
        link = "[[overlap-target]]"  # 18 bytes; spans bytes 75..93
        suffix = "b" * 110
        content = f"{prefix}{link}{suffix}"
        with tempfile.NamedTemporaryFile(mode="w", delete=False, suffix=".md") as f:
            f.write(content)
            temp_path = f.name

        try:
            chunker = DefaultFileChunker(chunk_byte_size=100, overlap_byte_size=20)
            _, chunks = await chunker.chunk(temp_path)
            # No chunk should start mid-link.
            for c in chunks:
                t = c.text
                if "]]" in t and "[[" not in t.split("]]", 1)[0]:
                    raise AssertionError(f"chunk starts mid-link: {t[:40]!r}")
            assert any(link in c.text for c in chunks)
            print("✓ test_chunk_does_not_split_wikilink_in_overlap passed")
        finally:
            os.unlink(temp_path)

    asyncio.run(run())


def test_chunk_falls_back_for_oversize_link():
    """If a single link exceeds half the chunk size, the parser hard-cuts to make progress."""

    async def run():
        # chunk=100, link is 80 bytes, surrounded by short filler.
        # Retreating would leave a tiny chunk (< 50), so the fallback kicks in.
        prefix = "x" * 30
        link = "[[" + ("L" * 76) + "]]"  # 80 bytes total
        suffix = "y" * 200
        content = f"{prefix}{link}{suffix}"
        with tempfile.NamedTemporaryFile(mode="w", delete=False, suffix=".md") as f:
            f.write(content)
            temp_path = f.name

        try:
            chunker = DefaultFileChunker(chunk_byte_size=100, overlap_byte_size=10)
            _, chunks = await chunker.chunk(temp_path)
            # Must terminate (not hang) and cover the whole file.
            assert len(chunks) >= 2
            print("✓ test_chunk_falls_back_for_oversize_link passed")
        finally:
            os.unlink(temp_path)

    asyncio.run(run())


def test_min_chunk_and_overlap_size():
    """Test that minimum chunk and overlap sizes are enforced."""

    async def run():
        # These values should be clamped to minimums
        chunker = DefaultFileChunker(chunk_byte_size=1, overlap_byte_size=0)
        assert chunker.chunk_byte_size == 100  # minimum
        assert chunker.overlap_byte_size == 4  # minimum

        content = "test"
        with tempfile.NamedTemporaryFile(mode="w", delete=False, suffix=".txt") as f:
            f.write(content)
            temp_path = f.name

        try:
            _, chunks = await chunker.chunk(temp_path)
            assert len(chunks) == 1
            print("✓ test_min_chunk_and_overlap_size passed")
        finally:
            os.unlink(temp_path)

    asyncio.run(run())


if __name__ == "__main__":
    test_parse_empty_file()
    test_parse_small_file()
    test_parse_chunked_file()
    test_parse_with_custom_encoding()
    test_parse_links_bare()
    test_parse_links_with_anchor()
    test_parse_links_alias_dropped()
    test_parse_links_anchor_and_alias()
    test_parse_links_ignores_legacy_relation_wrappers()
    test_parse_links_multiple_on_one_line()
    test_parse_wikilink_line_ranges()
    test_parse_markdown_links_are_ignored()
    test_parse_links_no_match()
    test_parse_links_in_file()
    test_parse_links_empty_when_no_content()
    test_chunk_does_not_split_wikilink_at_boundary()
    test_chunk_does_not_split_wikilink_in_overlap()
    test_chunk_falls_back_for_oversize_link()
    test_min_chunk_and_overlap_size()
    print("\n所有测试通过!")