"""Tests for DocumentIngestor.build_pages (spec §6.1)."""

from __future__ import annotations

from io import BytesIO
from pathlib import Path

import pytest

from ix.errors import IXErrorCode, IXException
from ix.ingestion import DocumentIngestor


def _make_pdf_bytes(n_pages: int) -> bytes:
    import fitz

    doc = fitz.open()
    for i in range(n_pages):
        page = doc.new_page(width=200, height=300)
        page.insert_text((10, 20), f"page {i+1}")
    out = doc.tobytes()
    doc.close()
    return out


def _make_multi_frame_tiff_bytes(n_frames: int) -> bytes:
    from PIL import Image

    frames = [Image.new("L", (10, 10), color=i * 30) for i in range(n_frames)]
    buf = BytesIO()
    frames[0].save(buf, format="TIFF", save_all=True, append_images=frames[1:])
    return buf.getvalue()


class TestPdf:
    def test_three_page_pdf_yields_three_pages(self, tmp_path: Path) -> None:
        p = tmp_path / "doc.pdf"
        p.write_bytes(_make_pdf_bytes(3))

        ing = DocumentIngestor()
        pages, metas = ing.build_pages(files=[(p, "application/pdf")], texts=[])

        assert len(pages) == 3
        for i, page in enumerate(pages, start=1):
            assert page.page_no == i
            assert page.width > 0
            assert page.height > 0
        assert len(metas) == 3
        for m in metas:
            assert m.file_index == 0

    def test_page_count_cap_raises_IX_000_006(self, tmp_path: Path) -> None:
        p = tmp_path / "toomany.pdf"
        p.write_bytes(_make_pdf_bytes(101))
        ing = DocumentIngestor()
        with pytest.raises(IXException) as ei:
            ing.build_pages(files=[(p, "application/pdf")], texts=[])
        assert ei.value.code is IXErrorCode.IX_000_006


class TestImages:
    def test_single_frame_png(self, tmp_path: Path) -> None:
        from PIL import Image

        p = tmp_path / "img.png"
        Image.new("RGB", (50, 80), color="white").save(p, format="PNG")
        ing = DocumentIngestor()
        pages, metas = ing.build_pages(files=[(p, "image/png")], texts=[])
        assert len(pages) == 1
        assert pages[0].width == 50
        assert pages[0].height == 80
        assert metas[0].file_index == 0

    def test_multi_frame_tiff_yields_multiple_pages(self, tmp_path: Path) -> None:
        p = tmp_path / "multi.tif"
        p.write_bytes(_make_multi_frame_tiff_bytes(2))

        ing = DocumentIngestor()
        pages, metas = ing.build_pages(files=[(p, "image/tiff")], texts=[])
        assert len(pages) == 2
        for page in pages:
            assert page.width == 10
            assert page.height == 10
        # Both frames share the same file_index.
        assert {m.file_index for m in metas} == {0}


class TestTexts:
    def test_texts_become_pages(self) -> None:
        ing = DocumentIngestor()
        pages, metas = ing.build_pages(files=[], texts=["hello", "world"])
        assert len(pages) == 2
        assert pages[0].page_no == 1
        assert pages[1].page_no == 2
        # Text-backed pages have no file_index source.
        assert metas[0].file_index is None
        assert metas[1].file_index is None


class TestFileIndexes:
    def test_multi_file_indexes_are_contiguous(self, tmp_path: Path) -> None:
        p1 = tmp_path / "a.pdf"
        p1.write_bytes(_make_pdf_bytes(2))
        p2 = tmp_path / "b.pdf"
        p2.write_bytes(_make_pdf_bytes(1))

        ing = DocumentIngestor()
        pages, metas = ing.build_pages(
            files=[(p1, "application/pdf"), (p2, "application/pdf")],
            texts=[],
        )
        assert len(pages) == 3
        # First two pages from file 0, last from file 1.
        assert metas[0].file_index == 0
        assert metas[1].file_index == 0
        assert metas[2].file_index == 1