"""Detect fully logged workout sessions (one POST /api/log batch)."""

from __future__ import annotations

from datetime import datetime

from sqlmodel import Session, select

from tracker.models import ProgramExercise, WorkoutLog


def session_batch_is_complete(
    day_label: str,
    batch_logs: list[WorkoutLog],
    expected: list[ProgramExercise],
) -> bool:
    """True when this batch has exactly the expected per-exercise set counts for the day."""
    if not batch_logs or not expected:
        return False
    if any(row.day_label != day_label for row in batch_logs):
        return False
    by_exercise: dict[int, int] = {}
    for row in batch_logs:
        by_exercise[row.exercise_id] = by_exercise.get(row.exercise_id, 0) + 1
    want_ids = {pe.exercise_id for pe in expected}
    if set(by_exercise.keys()) != want_ids:
        return False
    for pe in expected:
        if by_exercise.get(pe.exercise_id, 0) != pe.target_sets:
            return False
    return True


def find_last_completed_workout(
    session: Session,
    program_id: int,
) -> tuple[str | None, str | None]:
    """Most recent day_label and date (YYYY-MM-DD) where a full batch was logged."""
    logs = session.exec(
        select(WorkoutLog)
        .where(WorkoutLog.program_id == program_id)
        .order_by(WorkoutLog.logged_at.desc()),
    ).all()
    idx = 0
    while idx < len(logs):
        anchor = logs[idx].logged_at
        day_label = logs[idx].day_label
        batch: list[WorkoutLog] = []
        while idx < len(logs) and logs[idx].logged_at == anchor:
            batch.append(logs[idx])
            idx += 1
        same_day = [row for row in batch if row.day_label == day_label]
        expected = session.exec(
            select(ProgramExercise)
            .where(ProgramExercise.program_id == program_id)
            .where(ProgramExercise.day_label == day_label)
            .order_by(ProgramExercise.order_index),
        ).all()
        if session_batch_is_complete(day_label, same_day, list(expected)):
            logged_at = anchor
            date_str = logged_at.strftime("%Y-%m-%d") if isinstance(logged_at, datetime) else str(logged_at)[:10]
            return day_label, date_str
    return None, None