"""Tests for pdf2imos custom exception hierarchy and error handling."""

from pathlib import Path

import pymupdf
import pytest
from typer.testing import CliRunner

from pdf2imos.cli import app, process_pdf
from pdf2imos.errors import (
    DimensionExtractionError,
    OutputWriteError,
    Pdf2ImosError,
    PdfExtractionError,
    ViewSegmentationError,
)

runner = CliRunner()


# ---------------------------------------------------------------------------
# Helpers: create broken/edge-case PDFs on disk
# ---------------------------------------------------------------------------

def _create_non_pdf(path: Path) -> Path:
    """Write a plain-text file with .pdf extension."""
    path.write_text("This is not a PDF file at all.")
    return path


def _create_empty_pdf(path: Path) -> Path:
    """Write a minimal valid PDF structure with 0 pages."""
    pdf_bytes = (
        b"%PDF-1.4\n"
        b"1 0 obj\n<< /Type /Catalog /Pages 2 0 R >>\nendobj\n"
        b"2 0 obj\n<< /Type /Pages /Kids [] /Count 0 >>\nendobj\n"
        b"xref\n0 3\n"
        b"0000000000 65535 f \n"
        b"0000000010 00000 n \n"
        b"0000000059 00000 n \n"
        b"trailer\n<< /Size 3 /Root 1 0 R >>\n"
        b"startxref\n110\n%%EOF"
    )
    path.write_bytes(pdf_bytes)
    return path


def _create_text_only_pdf(path: Path) -> Path:
    """Create a PDF with text but zero vector paths (raster-like)."""
    doc = pymupdf.open()
    page = doc.new_page()
    page.insert_text((100, 100), "Hello world", fontsize=12)
    doc.save(str(path))
    doc.close()
    return path


# ---------------------------------------------------------------------------
# Test: Exception Hierarchy
# ---------------------------------------------------------------------------

class TestExceptionHierarchy:
    """Verify all custom exceptions inherit from Pdf2ImosError."""

    def test_pdf2imos_error_is_base(self):
        assert issubclass(Pdf2ImosError, Exception)

    def test_pdf_extraction_error_inherits(self):
        assert issubclass(PdfExtractionError, Pdf2ImosError)

    def test_view_segmentation_error_inherits(self):
        assert issubclass(ViewSegmentationError, Pdf2ImosError)

    def test_dimension_extraction_error_inherits(self):
        assert issubclass(DimensionExtractionError, Pdf2ImosError)

    def test_output_write_error_inherits(self):
        assert issubclass(OutputWriteError, Pdf2ImosError)

    def test_all_catchable_as_pdf2imos_error(self):
        """All custom exceptions can be caught via Pdf2ImosError."""
        for exc_class in (
            PdfExtractionError,
            ViewSegmentationError,
            DimensionExtractionError,
            OutputWriteError,
        ):
            with pytest.raises(Pdf2ImosError):
                raise exc_class("test")

    def test_output_write_error_can_be_raised(self):
        """OutputWriteError can be raised and caught independently."""
        with pytest.raises(OutputWriteError, match="disk full"):
            raise OutputWriteError("disk full")


# ---------------------------------------------------------------------------
# Test: process_pdf error paths
# ---------------------------------------------------------------------------

class TestProcessPdfErrors:
    """Verify process_pdf raises correct custom exceptions."""

    def test_non_pdf_raises_extraction_error(self, tmp_path):
        fake = _create_non_pdf(tmp_path / "fake.pdf")
        with pytest.raises(PdfExtractionError, match="Cannot open"):
            process_pdf(fake, tmp_path / "out")

    def test_empty_pdf_raises_extraction_error(self, tmp_path):
        empty = _create_empty_pdf(tmp_path / "empty.pdf")
        with pytest.raises(PdfExtractionError, match="Empty PDF"):
            process_pdf(empty, tmp_path / "out")

    def test_text_only_pdf_raises_no_vector_content(self, tmp_path):
        txt_pdf = _create_text_only_pdf(tmp_path / "text_only.pdf")
        with pytest.raises(
            PdfExtractionError, match="No vector content",
        ):
            process_pdf(txt_pdf, tmp_path / "out")


# ---------------------------------------------------------------------------
# Test: CLI handles errors gracefully (no crash/traceback to user)
# ---------------------------------------------------------------------------

class TestCliErrorHandling:
    """CLI should catch errors and exit with proper codes."""

    def test_non_pdf_file_exits_nonzero(self, tmp_path):
        """Non-PDF file → exit code 1 or 2, no unhandled crash."""
        in_dir = tmp_path / "in"
        in_dir.mkdir()
        _create_non_pdf(in_dir / "bad.pdf")
        out_dir = tmp_path / "out"
        result = runner.invoke(
            app, [str(in_dir), str(out_dir)],
        )
        assert result.exit_code in (1, 2)
        # No unhandled traceback in output
        assert result.exception is None or isinstance(
            result.exception, SystemExit,
        )

    def test_empty_pdf_exits_nonzero(self, tmp_path):
        """Empty PDF → exit code 1 or 2."""
        in_dir = tmp_path / "in"
        in_dir.mkdir()
        _create_empty_pdf(in_dir / "empty.pdf")
        out_dir = tmp_path / "out"
        result = runner.invoke(
            app, [str(in_dir), str(out_dir)],
        )
        assert result.exit_code in (1, 2)

    def test_empty_input_dir_exits_2(self, tmp_path):
        """No PDF files in input dir → exit code 2."""
        in_dir = tmp_path / "in"
        in_dir.mkdir()
        out_dir = tmp_path / "out"
        result = runner.invoke(
            app, [str(in_dir), str(out_dir)],
        )
        assert result.exit_code == 2

    def test_nonexistent_input_dir_exits_2(self, tmp_path):
        """Nonexistent input dir → exit code 2."""
        result = runner.invoke(
            app,
            [str(tmp_path / "nope"), str(tmp_path / "out")],
        )
        assert result.exit_code == 2

    def test_mixed_good_and_bad_exits_1(self, tmp_path):
        """Mix of valid + invalid PDFs → exit code 1 (partial)."""
        in_dir = tmp_path / "in"
        in_dir.mkdir()
        # Copy a real fixture
        fixture = (
            Path(__file__).parent
            / "fixtures" / "input" / "simple_panel.pdf"
        )
        (in_dir / "good.pdf").write_bytes(fixture.read_bytes())
        # Add a bad PDF
        _create_non_pdf(in_dir / "bad.pdf")
        out_dir = tmp_path / "out"
        result = runner.invoke(
            app, [str(in_dir), str(out_dir)],
        )
        assert result.exit_code == 1