"""PDF→Text-Konvertierung: pymupdf4llm primär, pdftotext-Fallback, mtime-Cache."""

import os
import time

import fitz  # PyMuPDF
import pytest

import blocks as blx


def _mini_pdf(path, text="Approximationsalgorithmen sind wichtig."):
    doc = fitz.open()
    page = doc.new_page()
    page.insert_text((72, 72), text, fontsize=12)
    doc.save(str(path))
    doc.close()


def test_convert_writes_markdown_txt(tmp_path):
    _mini_pdf(tmp_path / "skript.pdf")
    blx._convert_pdfs(tmp_path)
    out = (tmp_path / "skript.txt").read_text(encoding="utf-8")
    assert "Approximationsalgorithmen" in out


def test_cache_skips_fresh_txt(tmp_path):
    _mini_pdf(tmp_path / "a.pdf")
    marker = tmp_path / "a.txt"
    marker.write_text("MARKER", encoding="utf-8")
    now = time.time() + 60
    os.utime(marker, (now, now))
    blx._convert_pdfs(tmp_path)
    assert marker.read_text(encoding="utf-8") == "MARKER"  # nicht neu konvertiert


def test_fallback_to_pdftotext(tmp_path, monkeypatch):
    _mini_pdf(tmp_path / "b.pdf")
    monkeypatch.setattr(blx, "_pdf_markdown", lambda p: None)
    monkeypatch.setattr(blx, "_pdf_plaintext", lambda p: "fallback")
    blx._convert_pdfs(tmp_path)
    assert (tmp_path / "b.txt").read_text(encoding="utf-8") == "fallback"


def test_ocr_languages_from_tessdata(tmp_path, monkeypatch):
    import pymupdf

    monkeypatch.setattr(pymupdf, "get_tessdata", lambda: str(tmp_path))
    assert blx._ocr_languages() is None  # keine Sprachdaten → OCR aus
    (tmp_path / "eng.traineddata").touch()
    assert blx._ocr_languages() == "eng"
    (tmp_path / "deu.traineddata").touch()
    assert blx._ocr_languages() == "deu+eng"
    monkeypatch.setattr(pymupdf, "get_tessdata", lambda: (_ for _ in ()).throw(RuntimeError()))
    assert blx._ocr_languages() is None


def test_fidelity_guard_prefers_faithful_plaintext():
    plain = "Definition. P = {L ⊆ Σ | A ∈ L} und ≤ sowie häufig über. " * 20
    # Markdown verlor die Formeln (Symbole weg) → plain gewinnt
    md_lossy = "Definition. und sowie h¨aufig ¨uber. " * 20
    text, tool = blx._pick_conversion(md_lossy, plain)
    assert tool == "pdftotext"
    # Markdown treu (Symbole + Länge da) → md gewinnt
    md_ok = "# Def\n" + plain
    text, tool = blx._pick_conversion(md_ok, plain)
    assert tool == "pymupdf4llm"
    # nur eine Quelle verfügbar
    assert blx._pick_conversion(None, plain)[1] == "pdftotext"
    assert blx._pick_conversion(md_ok, None)[1] == "pymupdf4llm"
    assert blx._pick_conversion(None, None) is None