"""Read-only status snapshot: today, this week, shutdown projection, budgets.

Every function in this module only reads files already on disk — no ADB, no
sudo, no network, no writes. ``_status.py`` stays untouched (it's an
existing, tested, deliberately *mutating* CLI used by a human running
``--status`` who already expects that); this module is the new, genuinely
side-effect-free layer that both the i3blocks summary line and the Tkinter
status view are built on.
"""

from __future__ import annotations

from datetime import UTC, date, datetime, timedelta
from pathlib import Path

from screen_locker import _manual_workout
from screen_locker._compliance_state import explain_lock_decision
from screen_locker._status_projection import (
    _shutdown_projection,
    format_summary_line,
)
from screen_locker._status_types import (
    DayStatus,
    ManualWorkoutBudgetStatus,
    ShutdownProjection,
    ShutdownProjectionDay,
    StatusSnapshot,
    WeeklySummary,
)

__all__ = [
    "DayStatus",
    "ManualWorkoutBudgetStatus",
    "ShutdownProjection",
    "ShutdownProjectionDay",
    "StatusSnapshot",
    "WeeklySummary",
    "format_summary_line",
    "gather_status",
]
from screen_locker._constants import (
    EARLY_BIRD_PENDING_FILE,
    EXTRA_BENEFITS_FILE,
    MANUAL_WORKOUT_BUDGET_PER_7_DAYS,
    MANUAL_WORKOUT_BUDGET_PER_30_DAYS,
    SHUTDOWN_CONFIG_FILE,
)
from screen_locker._extra_benefits import (
    current_streak,
    has_extended_early_bird,
)
from screen_locker._log_io import load_workout_log
from screen_locker._morning_session import has_workout_skip_today
from screen_locker._night_lockdown import tonights_lockdown
from screen_locker._sick import workout_standdown_dates
from screen_locker._weekly_check import (
    COUNTED_WORKOUT_TYPES,
    WEEKLY_WORKOUT_MINIMUM,
    count_day_credits,
    is_relaxed_day,
)

_DEFAULT_LOG_FILE = Path(__file__).resolve().parent / "log.json"


def _day_status(
    day_date: date, entries: list[dict], sick_days: frozenset[date]
) -> DayStatus:
    """Build a :class:`DayStatus` for one calendar day from its entry list.

    ``day_count`` comes from
    :func:`~screen_locker._weekly_check.count_day_credits`, the same rule
    enforcement uses, so the week total sums to
    :func:`~screen_locker._weekly_check.count_weekly_workouts` by construction.
    It used to re-derive the rule as ``verified + (1 if has_manual else 0)``,
    which disagreed on any day with two manual workouts -- and since this value
    feeds the status view's ``weekly_minimum_met`` explanation, the window could
    explain a different decision than the locker actually made.
    """
    iso = day_date.isoformat()
    label = day_date.strftime("%a %b %d")
    types = tuple(
        str(e.get("workout_data", {}).get("type", ""))
        for e in entries
        if isinstance(e, dict)
    )
    sources = [
        str(e.get("workout_data", {}).get("source", ""))
        for e in entries
        if isinstance(e, dict)
    ]
    return DayStatus(
        date=iso,
        label=label,
        entry_types=tuple(t for t in types if t),
        source=" · ".join(s for s in sources if s),
        counted=any(t in COUNTED_WORKOUT_TYPES for t in types),
        day_count=count_day_credits(iso, [e for e in entries if isinstance(e, dict)]),
        is_sick_day=day_date in sick_days,
    )


def _week_days(log_file: Path, *, today_local: datetime) -> tuple[DayStatus, ...]:
    """Return this ISO week's days from Monday through today."""
    log_data = load_workout_log(log_file)
    sick_days = workout_standdown_dates()
    today_date = today_local.date()
    monday = today_date - timedelta(days=today_date.weekday())
    days: list[DayStatus] = []
    day = monday
    while day <= today_date:
        days.append(_day_status(day, log_data.get(day.isoformat(), []), sick_days))
        day += timedelta(days=1)
    return tuple(days)


def _weekly_summary(days: tuple[DayStatus, ...]) -> WeeklySummary:
    """Summarize a week's workout count against the weekly minimum."""
    counted = sum(d.day_count for d in days)
    return WeeklySummary(
        days=days,
        counted_count=counted,
        minimum=WEEKLY_WORKOUT_MINIMUM,
        remaining=max(0, WEEKLY_WORKOUT_MINIMUM - counted),
        extra=max(0, counted - WEEKLY_WORKOUT_MINIMUM),
    )


def _manual_workout_budget_status(
    log_file: Path, *, today: str
) -> ManualWorkoutBudgetStatus:
    """Summarize rolling manual-workout budget usage."""
    return ManualWorkoutBudgetStatus(
        used_7d=_manual_workout.count_in_window(log_file, 7, today=today),
        budget_7d=MANUAL_WORKOUT_BUDGET_PER_7_DAYS,
        used_30d=_manual_workout.count_in_window(log_file, 30, today=today),
        budget_30d=MANUAL_WORKOUT_BUDGET_PER_30_DAYS,
        exhausted=_manual_workout.is_budget_exhausted(log_file, today=today),
    )


def gather_status(
    *,
    log_file: Path = _DEFAULT_LOG_FILE,
    extra_benefits_file: Path = EXTRA_BENEFITS_FILE,
    shutdown_config_file: Path = SHUTDOWN_CONFIG_FILE,
    early_bird_pending_file: Path = EARLY_BIRD_PENDING_FILE,
    now: datetime | None = None,
) -> StatusSnapshot:
    """Gather a full :class:`StatusSnapshot` from on-disk state only.

    Never touches ADB, sudo, or the network — safe to call on every i3blocks
    tick and every status-window open/refresh.
    """
    instant = now if now is not None else datetime.now(tz=UTC)
    today_local = instant.astimezone()
    today_str = today_local.date().isoformat()

    days = _week_days(log_file, today_local=today_local)
    week = _weekly_summary(days)
    early_bird_extended = has_extended_early_bird(
        extra_benefits_file, today=today_local
    )

    lock_explanation = explain_lock_decision(
        log_file=log_file,
        early_bird_pending_file=early_bird_pending_file,
        weekly_minimum_met=week.counted_count >= WEEKLY_WORKOUT_MINIMUM,
        relaxed_day=is_relaxed_day(today=today_local),
        wake_skip=has_workout_skip_today(),
        evening_lockdown=tonights_lockdown(instant) is not None,
        now=instant,
    )

    return StatusSnapshot(
        today=days[-1],
        week=week,
        streak=current_streak(extra_benefits_file),
        early_bird_extended=early_bird_extended,
        shutdown=_shutdown_projection(
            shutdown_config_file=shutdown_config_file,
            today_local=today_local,
        ),
        lock_explanation=lock_explanation,
        manual_workout_budget=_manual_workout_budget_status(log_file, today=today_str),
        generated_at=instant.isoformat(),
    )