"""ResponseHandlerStep — final shape-up before the caller sees the payload (spec §8).

Does three purely mechanical things:

1. When ``include_ocr_text`` is set, concatenate every non-tag line text
   into ``ocr_result.result.text`` (pages joined with blank line).
2. When ``include_geometries`` is **not** set (the default), strip
   ``ocr_result.result.pages`` and ``ocr_result.meta_data`` — geometries
   are heavyweight; callers opt in.
3. Clear ``response_ix.context`` (belt-and-braces — ``Field(exclude=True)``
   already keeps it out of ``model_dump`` output).

:meth:`validate` always returns True per spec.
"""

from __future__ import annotations

import re

from ix.contracts import RequestIX, ResponseIX
from ix.pipeline.step import Step

_PAGE_TAG_RE = re.compile(r"^\s*<\s*/?\s*page\b", re.IGNORECASE)


def _is_page_tag(text: str | None) -> bool:
    if not text:
        return False
    return bool(_PAGE_TAG_RE.match(text))


class ResponseHandlerStep(Step):
    """Final shape-up step."""

    async def validate(self, request_ix: RequestIX, response_ix: ResponseIX) -> bool:
        return True

    async def process(
        self, request_ix: RequestIX, response_ix: ResponseIX
    ) -> ResponseIX:
        ocr_opts = request_ix.options.ocr

        # 1. Attach flat OCR text if requested.
        if ocr_opts.include_ocr_text:
            page_texts: list[str] = []
            for page in response_ix.ocr_result.result.pages:
                line_texts = [
                    line.text or ""
                    for line in page.lines
                    if not _is_page_tag(line.text)
                ]
                page_texts.append("\n".join(line_texts))
            response_ix.ocr_result.result.text = "\n\n".join(page_texts) or None

        # 2. Strip geometries unless explicitly retained.
        if not ocr_opts.include_geometries:
            response_ix.ocr_result.result.pages = []
            response_ix.ocr_result.meta_data = {}

        # 3. Drop the internal context — already Field(exclude=True),
        # this is defense in depth.
        response_ix.context = None

        return response_ix


__all__ = ["ResponseHandlerStep"]