admin / Apex

"""Bid plan back-scheduling from the submission date (Module 2 step 3)."""
from __future__ import annotations

from datetime import date, timedelta


def sub_working_days(end: date, working_days: int) -> date:
    """Return the date `working_days` business days before `end`."""
    d = end
    remaining = working_days
    while remaining > 0:
        d -= timedelta(days=1)
        if d.weekday() < 5:  # Mon-Fri
            remaining -= 1
    return d


def build_plan(start_date: date, submission_date: date, milestones: list[dict],
               requirements: list[dict]) -> list[dict]:
    """Return plan task dicts (milestones + one task per requirement)."""
    tasks: list[dict] = []
    for m in milestones:
        if m.get("from") == "start":
            due = start_date
        else:
            due = sub_working_days(submission_date, int(m.get("offset_working_days_before_submission", 0)))
        tasks.append({
            "name": m["name"],
            "kind": "milestone",
            "requirement_id": None,
            "due": due.isoformat(),
            "start": due.isoformat(),
            "status": "pending",
        })

    # requirement tasks: spread between "requirement review complete" window and
    # "first drafts complete" milestone, defaulting to submission - 12 wd.
    draft_due = sub_working_days(submission_date, 12)
    for req in requirements:
        tasks.append({
            "name": f"Respond to {req.get('ref') or 'requirement'}",
            "kind": "task",
            "requirement_id": req.get("id"),
            "due": draft_due.isoformat(),
            "start": start_date.isoformat(),
            "status": "pending",
            "planned_hours": 4,
        })
    return tasks