"""Phase 8 tests: Q&A metadata enrichment (Sub-Phase 8.2).

Covers:
- Metadata enrichment with Q&A-specific fields via chunk_metadata param
- Backward compatibility: token strategy unchanged
- Page number references question location
- Chunk metadata merging with base metadata
"""
import json

import pytest

from app.utils.metadata import extract_metadata


def test_qa_metadata_fields(tmp_path):
    """strategy_type, question_index, question_id, question_text merged via chunk_metadata."""
    file_path = tmp_path / "test.pdf"
    file_path.write_text("dummy content")

    chunks = ["chunk 1", "chunk 2"]
    chunk_metadata = [
        {
            "strategy_type": "question",
            "section_type": "qa",
            "question_index": 0,
            "question_id": "A1",
            "question_text": "What is X?",
            "section_heading": "(A) Section",
            "answer_contains_table": True,
            "source_page_range": [2, 5],
            "parent_topic": "Topic Name",
        },
        {
            "strategy_type": "question",
            "section_type": "qa",
            "question_index": 1,
            "question_id": "A2",
            "question_text": "What is Y?",
            "section_heading": "(A) Section",
            "answer_contains_table": False,
            "source_page_range": [5, 7],
        },
    ]

    metadata = extract_metadata(
        file_path=str(file_path),
        chunks=chunks,
        strategy_type="question",
        chunk_metadata=chunk_metadata,
    )
    assert len(metadata) == 2

    m0 = metadata[0]
    assert m0["strategy_type"] == "question"
    assert m0["section_type"] == "qa"
    assert m0["question_index"] == 0
    assert m0["question_id"] == "A1"
    assert m0["question_text"] == "What is X?"
    assert m0["section_heading"] == "(A) Section"
    assert m0["answer_contains_table"] is True
    assert m0["source_page_range"] == [2, 5]
    assert m0["parent_topic"] == "Topic Name"

    m1 = metadata[1]
    assert m1["question_index"] == 1
    assert m1["question_id"] == "A2"
    assert m1["answer_contains_table"] is False


def test_qa_metadata_topic_section(tmp_path):
    """section_heading and parent_topic are both preserved."""
    file_path = tmp_path / "test.pdf"
    file_path.write_text("dummy content")

    metadata = extract_metadata(
        file_path=str(file_path),
        chunks=["chunk"],
        strategy_type="question",
        chunk_metadata=[{"section_heading": "(B) Traffic", "parent_topic": "Traffic Planning"}],
    )
    assert metadata[0]["section_heading"] == "(B) Traffic"
    assert metadata[0]["parent_topic"] == "Traffic Planning"


def test_token_metadata_unchanged(tmp_path):
    """Existing metadata fields unchanged for token strategy (no chunk_metadata)."""
    file_path = tmp_path / "test.txt"
    file_path.write_text("test content")

    metadata = extract_metadata(
        file_path=str(file_path),
        chunks=["chunk 1", "chunk 2"],
        original_filename="original.txt",
        strategy_type="token",
    )
    assert len(metadata) == 2
    for m in metadata:
        assert "filename" in m
        assert "upload_date" in m
        assert "content_summary" in m
        assert "chunk_index" in m
        assert m.get("strategy_type", "token") == "token"
        assert "question_id" not in m


def test_page_number_from_question(tmp_path):
    """Page ref should point to question location (pass via page_numbers from strategy)."""
    file_path = tmp_path / "test.pdf"
    file_path.write_text("dummy content")

    metadata = extract_metadata(
        file_path=str(file_path),
        chunks=["question chunk"],
        page_numbers=[3],
        strategy_type="question",
        chunk_metadata=[{
            "question_id": "A1",
            "source_page_range": [3, 8],
        }],
    )
    assert metadata[0]["page_number"] == 3
    assert metadata[0]["source_page_range"] == [3, 8]


def test_chunk_metadata_length_mismatch(tmp_path):
    """chunk_metadata length mismatch with chunks raises ValueError."""
    file_path = tmp_path / "test.pdf"
    file_path.write_text("dummy content")

    with pytest.raises(ValueError, match="chunk_metadata length"):
        extract_metadata(
            file_path=str(file_path),
            chunks=["a", "b", "c"],
            chunk_metadata=[{}, {}],
        )


def test_chunk_metadata_empty_no_error(tmp_path):
    """Empty chunk_metadata list with matching chunks is valid."""
    file_path = tmp_path / "test.pdf"
    file_path.write_text("dummy content")

    metadata = extract_metadata(
        file_path=str(file_path),
        chunks=["a"],
        chunk_metadata=[],
    )
    assert len(metadata) == 1