"""Shared authoritative PDF-report service for Flask and MCP adapters."""

from __future__ import annotations

from datetime import datetime
import json
from pathlib import Path
from typing import Any

from pdf_report import (
    report_from_calculation_result,
    render_roll_report,
    safe_report_filename,
)
from roll_calculation import calculate_roll


UNKNOWN_BUILD_INFO = {
    "version": "unknown",
    "branch": "unknown",
    "commit": "unknown",
    "timestamp": "unknown",
}


def create_roll_calculation_pdf(
    calculation_request: Any,
    *,
    build_info: dict[str, str],
) -> tuple[bytes, str, dict[str, Any]]:
    """Recalculate one request and render the established RollCalc PDF."""
    result = calculate_roll(calculation_request, build_info=build_info)
    pdf, filename = create_roll_calculation_pdf_from_result(
        result,
        build_info=build_info,
    )
    return pdf, filename, result


def create_roll_calculation_pdf_from_result(
    result: dict[str, Any],
    *,
    build_info: dict[str, str],
) -> tuple[bytes, str]:
    """Render an already-authoritative calculation result using the shared path."""
    report = report_from_calculation_result(result)
    generated_at = datetime.now().astimezone()
    pdf = render_roll_report(
        report,
        generated_at=generated_at,
        build_info=build_info,
    )
    article_number = report["article"]["number"] if report["article"] else None
    return pdf, safe_report_filename(article_number, generated_at)


def load_report_build_info(path: str = "build_info.json") -> dict[str, str]:
    """Load the same optional build metadata shown by Flask-generated reports."""
    try:
        raw = json.loads(Path(path).read_text(encoding="utf-8"))
    except (OSError, json.JSONDecodeError):
        return UNKNOWN_BUILD_INFO.copy()
    if not isinstance(raw, dict):
        return UNKNOWN_BUILD_INFO.copy()
    build_info = UNKNOWN_BUILD_INFO.copy()
    for key in build_info:
        value = raw.get(key)
        if isinstance(value, str) and value.strip():
            build_info[key] = value.strip()
    return build_info