Model/orchestration/scenario_export_orchestrator.py

"""The Scenario Export orchestrator (ADR-0065).

Ties one export together: for each requested Scenario, read its Properties'
persisted rows, shape them into a sheet, render the sheet-per-scenario branded
workbook, upload it to the exports bucket, mint a presigned URL, and email the
requester. Best-effort email (the link is also recorded on ``sub_task.outputs``);
a selection that yields no rows for any Scenario is a recorded failure — never an
empty workbook emailed to the user.
"""

from __future__ import annotations

import html
import logging
import os
import tempfile
from dataclasses import dataclass
from typing import Protocol, Sequence

from domain.scenario_export.scenario_sheet import (
    ExportSheet,
    PropertyScenarioData,
    shape_scenario_sheet,
)
from domain.tasks.subtasks import SubTaskFailure
from infrastructure.s3.s3_client import S3Client
from infrastructure.xlsx.scenario_export_workbook import render_workbook
from repositories.email.email_sender import EmailSender

logger = logging.getLogger(__name__)


class ExportRowReader(Protocol):
    def rows_for(
        self,
        *,
        portfolio_id: int,
        scenario_id: int,
        property_ids: Sequence[int],
    ) -> list[PropertyScenarioData]: ...


class ScenarioNames(Protocol):
    def name_for(self, scenario_id: int) -> str: ...


@dataclass(frozen=True)
class ScenarioExportResult:
    """What a completed export reports (lands on ``sub_task.outputs``)."""

    presigned_url: str
    export_s3_key: str
    sheet_count: int
    row_count: int


class ScenarioExportOrchestrator:
    def __init__(
        self,
        *,
        rows: ExportRowReader,
        scenarios: ScenarioNames,
        exports: S3Client,
        email: EmailSender,
        url_ttl_seconds: int,
        key_prefix: str = "scenario-exports",
    ) -> None:
        self._rows = rows
        self._scenarios = scenarios
        self._exports = exports
        self._email = email
        self._url_ttl_seconds = url_ttl_seconds
        self._key_prefix = key_prefix

    def run(
        self,
        *,
        portfolio_id: int,
        scenario_ids: Sequence[int],
        property_ids: Sequence[int],
        recipient_email: str,
        export_name: str,
    ) -> ScenarioExportResult:
        named_sheets: list[tuple[str, ExportSheet]] = []
        row_count = 0
        for scenario_id in scenario_ids:
            rows = self._rows.rows_for(
                portfolio_id=portfolio_id,
                scenario_id=scenario_id,
                property_ids=property_ids,
            )
            sheet = shape_scenario_sheet(rows)
            named_sheets.append((self._scenarios.name_for(scenario_id), sheet))
            row_count += len(sheet.rows)

        if row_count == 0:
            # No Property had a default Plan under any requested Scenario (model
            # A) — a recorded failure, never an empty workbook emailed (ADR-0065).
            raise SubTaskFailure(
                "the scenario export selection produced no exportable rows",
                details={
                    "portfolio_id": portfolio_id,
                    "scenario_ids": list(scenario_ids),
                    "property_count": len(property_ids),
                },
            )

        key = f"{self._key_prefix}/{export_name}.xlsx"
        # Render to a /tmp file and multipart-upload it, so the workbook is never
        # also held in memory as a bytes copy (ADR-0065 — the OOM path at the
        # 100k-row cap). The temp file is always cleaned up.
        handle, workbook_path = tempfile.mkstemp(suffix=".xlsx")
        os.close(handle)
        try:
            render_workbook(named_sheets, workbook_path)
            self._exports.upload_file(workbook_path, key)
        finally:
            try:
                os.remove(workbook_path)
            except OSError:
                pass
        url = self._exports.generate_presigned_url(key, self._url_ttl_seconds)

        subject, body, html_body = self._compose_email(
            url=url, sheets=len(named_sheets), rows=row_count
        )
        try:
            self._email.send(
                to=recipient_email, subject=subject, body=body, html_body=html_body
            )
            logger.info("scenario_export: emailed %s", recipient_email)
        except Exception:
            # Best-effort delivery (ADR-0065): the link is also written to
            # sub_task.outputs, so an email/transport failure must not lose an
            # export that was already built and uploaded.
            logger.warning(
                "scenario_export: email delivery to %s failed; the link is still "
                "recorded on sub_task.outputs",
                recipient_email,
                exc_info=True,
            )

        return ScenarioExportResult(
            presigned_url=url,
            export_s3_key=key,
            sheet_count=len(named_sheets),
            row_count=row_count,
        )

    def _compose_email(
        self, *, url: str, sheets: int, rows: int
    ) -> tuple[str, str, str]:
        """The delivery email (ADR-0059/0065): a subject, a plain-text body
        carrying the raw link, and an HTML alternative with a clean download
        button so the long presigned URL isn't the visible content."""
        minutes = self._url_ttl_seconds // 60
        sheet_noun = "scenario" if sheets == 1 else "scenarios"
        subject = f"Your scenario export is ready ({sheets} {sheet_noun})"
        body = (
            "Your scenario export is ready.\n\n"
            f"It covers {sheets} {sheet_noun} across {rows} property row(s).\n\n"
            f"Download it here (link valid for {minutes} minutes):\n{url}\n"
        )
        safe_url = html.escape(url, quote=True)
        html_body = (
            '<div style="font-family:Arial,Helvetica,sans-serif;font-size:15px;'
            'color:#1a1a1a;line-height:1.5;">'
            "<p>Your scenario export is ready.</p>"
            f"<p>It covers <strong>{sheets}</strong> {sheet_noun} across "
            f"<strong>{rows}</strong> property row(s).</p>"
            '<p style="margin:24px 0;">'
            f'<a href="{safe_url}" style="display:inline-block;padding:12px 22px;'
            "background:#6C6CFF;color:#ffffff;text-decoration:none;border-radius:6px;"
            'font-weight:bold;">Download export</a></p>'
            f'<p style="color:#666;font-size:13px;">This link expires in {minutes} '
            "minutes. If the button doesn't work, paste this URL into your browser:"
            f'<br><span style="word-break:break-all;">{safe_url}</span></p>'
            "</div>"
        )
        return subject, body, html_body