"""
Notification template builders for ntfy push notifications.

Each build_* function returns a dict with keys: title, message, tags, priority.
These are passed directly to send_ntfy_notification().
"""
from datetime import datetime, date
from typing import Optional


# ── Shared helpers ────────────────────────────────────────────────────────────

def urgency_label(target_date: date, today: date) -> str:
    """Human-readable urgency string relative to today."""
    delta = (target_date - today).days
    if delta < 0:
        return f"OVERDUE ({abs(delta)}d ago)"
    elif delta == 0:
        return "Today"
    elif delta == 1:
        return "Tomorrow"
    elif delta <= 7:
        return f"in {delta} days"
    else:
        return target_date.strftime("%d %b")


def day_str(dt: datetime, today: date) -> str:
    """Return 'Today', 'Tomorrow', or a short date string."""
    d = dt.date()
    if d == today:
        return "Today"
    delta = (d - today).days
    if delta == 1:
        return "Tomorrow"
    return dt.strftime("%a %d %b")


def time_str(dt: datetime, all_day: bool = False) -> str:
    """Return 'All day' or HH:MM."""
    if all_day:
        return "All day"
    return dt.strftime("%H:%M")


def _truncate(text: str, max_len: int) -> str:
    """Truncate with ellipsis if over limit."""
    return (text[:max_len - 3] + "...") if len(text) > max_len else text


# ── Template builders ─────────────────────────────────────────────────────────

def build_event_notification(
    title: str,
    start_datetime: datetime,
    all_day: bool,
    today: date,
    location_name: Optional[str] = None,
    description: Optional[str] = None,
    is_starred: bool = False,
) -> dict:
    """Build notification payload for a calendar event reminder."""
    day = day_str(start_datetime, today)
    time = time_str(start_datetime, all_day)
    loc = f" @ {location_name}" if location_name else ""
    desc = f" — {description[:80]}" if description else ""

    return {
        "title": _truncate(f"Calendar: {title}", 80),
        "message": _truncate(f"{day} at {time}{loc}{desc}", 200),
        "tags": ["calendar"],
        "priority": 4 if is_starred else 3,
    }


def build_reminder_notification(
    title: str,
    remind_at: datetime,
    today: date,
    description: Optional[str] = None,
) -> dict:
    """Build notification payload for a general reminder."""
    day = day_str(remind_at, today)
    time = time_str(remind_at)
    desc = f" — {description[:80]}" if description else ""

    return {
        "title": _truncate(f"Reminder: {title}", 80),
        "message": _truncate(f"{day} at {time}{desc}", 200),
        "tags": ["bell"],
        "priority": 3,
    }


def build_todo_notification(
    title: str,
    due_date: date,
    today: date,
    priority: str = "medium",
    category: Optional[str] = None,
) -> dict:
    """Build notification payload for a todo due date alert."""
    urgency = urgency_label(due_date, today)
    priority_label = priority.capitalize()
    cat = f" [{category}]" if category else ""
    # High priority for today/overdue, default otherwise
    ntfy_priority = 4 if (due_date - today).days <= 0 else 3

    return {
        "title": _truncate(f"Due {urgency}: {title}", 80),
        "message": _truncate(f"Priority: {priority_label}{cat}", 200),
        "tags": ["white_check_mark"],
        "priority": ntfy_priority,
    }


def build_project_notification(
    name: str,
    due_date: date,
    today: date,
    status: str = "in_progress",
) -> dict:
    """Build notification payload for a project deadline alert."""
    urgency = urgency_label(due_date, today)
    # Format status label
    status_label = status.replace("_", " ").title()
    ntfy_priority = 4 if due_date <= today else 3

    return {
        "title": _truncate(f"Project Deadline: {name}", 80),
        "message": _truncate(f"Due {urgency} — Status: {status_label}", 200),
        "tags": ["briefcase"],
        "priority": ntfy_priority,
    }