import pytest
from chunks.models import Block
from chunks.config import ChunkerConfig
from chunks.packer import pack


def make_block(idx: int, content: str, kind: str = "paragraph", atomic: bool = False,
               header_path=None) -> Block:
    hp = header_path or [{"level": 1, "text": "Titolo"}]
    return Block(
        id=f"blk_{idx:04d}", kind=kind, content=content, plain_text=content,
        atomic=atomic, start_line=idx * 2, end_line=idx * 2 + 1,
        header_path=hp, chars=len(content),
    )


@pytest.fixture
def cfg():
    return ChunkerConfig(min_chars=10, target_chars=50, max_chars=100)


def test_single_block_becomes_single_chunk(cfg):
    blocks = [make_block(1, "Testo breve.")]
    chunks = pack(blocks, cfg, "test")
    assert len(chunks) == 1
    assert chunks[0].content_original == "Testo breve."


def test_chunk_id_format(cfg):
    blocks = [make_block(1, "Testo.")]
    chunks = pack(blocks, cfg, "test")
    assert chunks[0].chunk_id.startswith("chk_")


def test_neighbors_populated(cfg):
    blocks = [make_block(i, "x" * 60, header_path=[{"level": 1, "text": "T"}]) for i in range(1, 4)]
    chunks = pack(blocks, cfg, "test")
    assert len(chunks) >= 2
    assert chunks[0].neighbors["next_chunk_id"] == chunks[1].chunk_id
    assert chunks[1].neighbors["previous_chunk_id"] == chunks[0].chunk_id
    assert chunks[-1].neighbors["next_chunk_id"] is None


def test_blocks_merged_until_target(cfg):
    blocks = [make_block(i, "x" * 20) for i in range(1, 4)]
    chunks = pack(blocks, cfg, "test")
    assert len(chunks) >= 2


def test_oversized_paragraph_split(cfg):
    long_content = ("Questa è la prima frase completa. " * 5).strip()
    blocks = [make_block(1, long_content)]
    chunks = pack(blocks, cfg, "test")
    for c in chunks:
        assert c.chars <= cfg.max_chars or c.flags["is_overflow"]


def test_atomic_block_not_split(cfg):
    atomic_content = "```python\n" + "codice\n" * 20 + "```"
    blocks = [make_block(1, atomic_content, kind="code", atomic=True)]
    chunks = pack(blocks, cfg, "test")
    assert len(chunks) == 1
    assert chunks[0].flags["is_overflow"] is True
    assert chunks[0].content_type == "overflow"


def test_heading_path_break_creates_new_chunk(cfg):
    hp1 = [{"level": 1, "text": "Sezione 1"}]
    hp2 = [{"level": 1, "text": "Sezione 2"}]
    blocks = [make_block(1, "x" * 30, header_path=hp1), make_block(2, "x" * 30, header_path=hp2)]
    chunks = pack(blocks, cfg, "test")
    assert len(chunks) == 2
    assert chunks[0].header_path == hp1
    assert chunks[1].header_path == hp2


def test_content_for_embedding_has_header_prefix(cfg):
    blocks = [make_block(1, "Contenuto.", header_path=[{"level": 1, "text": "Guida"},
                                                        {"level": 2, "text": "Intro"}])]
    chunks = pack(blocks, cfg, "test")
    assert "Guida" in chunks[0].content_for_embedding
    assert "Intro" in chunks[0].content_for_embedding
    assert "Contenuto." in chunks[0].content_for_embedding


def test_thematic_break_flushes_chunk(cfg):
    blocks = [
        make_block(1, "x" * 30),
        make_block(2, "---", kind="thematic_break"),
        make_block(3, "x" * 30),
    ]
    chunks = pack(blocks, cfg, "test")
    assert len(chunks) == 2


def test_flags_has_code(cfg):
    blocks = [make_block(1, "```\ncode\n```", kind="code", atomic=True)]
    chunks = pack(blocks, cfg, "test")
    assert chunks[0].flags["has_code"] is True


def test_flags_has_table(cfg):
    blocks = [make_block(1, "| A | B |\n|---|---|\n| 1 | 2 |", kind="table", atomic=True)]
    chunks = pack(blocks, cfg, "test")
    assert chunks[0].flags["has_table"] is True


def test_chunk_index_sequential(cfg):
    blocks = [make_block(i, "x" * 60) for i in range(1, 5)]
    chunks = pack(blocks, cfg, "test")
    for i, c in enumerate(chunks):
        assert c.chunk_index == i


def test_assets_empty(cfg):
    blocks = [make_block(1, "Testo.")]
    chunks = pack(blocks, cfg, "test")
    assert chunks[0].assets == []


def test_flags_has_math_via_kind(cfg):
    blocks = [make_block(1, "$$\nE=mc^2\n$$", kind="math", atomic=True)]
    chunks = pack(blocks, cfg, "test")
    assert chunks[0].flags["has_math"] is True


def test_flags_has_math_via_content_dollars(cfg):
    # Paragrafo con $$ inline (senza dollarmath plugin attivo)
    blocks = [make_block(1, "Vedi la formula:\n$$\nx^2\n$$")]
    chunks = pack(blocks, cfg, "test")
    assert chunks[0].flags["has_math"] is True


def test_flags_has_math_via_content_begin(cfg):
    blocks = [make_block(1, r"Equazione: \begin{align} x = 1 \end{align}")]
    chunks = pack(blocks, cfg, "test")
    assert chunks[0].flags["has_math"] is True


def test_flags_has_table_via_html(cfg):
    html_content = "<table><tr><td>A</td></tr></table>"
    blocks = [make_block(1, html_content, kind="html", atomic=True)]
    chunks = pack(blocks, cfg, "test")
    assert chunks[0].flags["has_table"] is True


def test_flags_no_math_plain_text(cfg):
    blocks = [make_block(1, "Testo normale senza formule.")]
    chunks = pack(blocks, cfg, "test")
    assert chunks[0].flags["has_math"] is False