"""Shared domain logic for intelligent-eval scheduling, priority, attention.

Centralises the time-slot / deficit / severity calculations that previously
lived in `task_queue` and `decision` (P1 deepening, S1). Both modules now
delegate here so a single source of truth governs "8-10h"-style semantics.
"""
from datetime import datetime, timedelta
from typing import Optional

from sqlmodel import Session, select

from agenteval.storage.db import (
    IntelligentEvalDB,
    IntelligentEvalSessionDB,
    as_utc,
    utc_now,
)

# ---------------------------------------------------------------------------
# Time-slot parsing
# ---------------------------------------------------------------------------


def parse_time_slot(time_slot: str) -> Optional[tuple[float, float]]:
    """Parse a slot into (start_hours, end_hours), both in hours.

    Supports hour-level ("8-10h" -> (8, 10)) and minute-level ("0-20min" ->
    (0, 1/3)) slots. planner 对短窗口（如 1h）会用分钟级时段，长窗口用
    小时级；统一换算成小时（float）供上层判断。Returns None on bad format.
    """
    try:
        raw = time_slot.strip().lower()
        factor = 1.0
        if raw.endswith("min"):
            raw = raw[:-3]
            factor = 1.0 / 60
        elif raw.endswith("h"):
            raw = raw[:-1]
            factor = 1.0
        parts = raw.split("-")
        if len(parts) != 2:
            return None
        return (int(parts[0]) * factor, int(parts[1]) * factor)
    except (ValueError, AttributeError):
        return None


def is_slot_due(slot: dict, current_offset: timedelta) -> bool:
    """True if the slot's start hour has been reached."""
    parsed = parse_time_slot(slot.get("time_slot", ""))
    if parsed is None:
        return False
    start_hour, _ = parsed
    return current_offset >= timedelta(hours=start_hour)


def get_current_slot(time_distribution: list[dict], current_offset: timedelta) -> Optional[dict]:
    """Return the slot dict whose [start, end) contains the current offset."""
    current_hours = current_offset.total_seconds() / 3600
    for slot in time_distribution:
        parsed = parse_time_slot(slot.get("time_slot", ""))
        if parsed is None:
            continue
        start_hour, end_hour = parsed
        if start_hour <= current_hours < end_hour:
            return slot
    return None


# ---------------------------------------------------------------------------
# Session accounting
# ---------------------------------------------------------------------------


def count_sessions_in_slot(
    eval_id: str, slot: dict, eval_started_at: datetime, session: Session
) -> int:
    """Count sessions of this eval whose created_at falls in the slot window."""
    parsed = parse_time_slot(slot.get("time_slot", ""))
    if parsed is None:
        return 0
    start_hour, end_hour = parsed
    slot_start = (as_utc(eval_started_at) + timedelta(hours=start_hour)).replace(tzinfo=None)
    slot_end = (as_utc(eval_started_at) + timedelta(hours=end_hour)).replace(tzinfo=None)
    rows = session.exec(
        select(IntelligentEvalSessionDB).where(
            IntelligentEvalSessionDB.eval_id == eval_id,
            IntelligentEvalSessionDB.created_at >= slot_start,
            IntelligentEvalSessionDB.created_at < slot_end,
        )
    ).all()
    return len(rows)


def count_total_sessions(eval_id: str, session: Session) -> int:
    rows = session.exec(
        select(IntelligentEvalSessionDB).where(IntelligentEvalSessionDB.eval_id == eval_id)
    ).all()
    return len(rows)


def calculate_session_deficit(eval_db: IntelligentEvalDB, session: Session) -> int:
    """Total sessions that should exist by now minus what actually exists."""
    if not eval_db.plan:
        return 0
    plan = eval_db.get_plan()
    time_distribution = plan.get("time_distribution", [])
    current_offset = (
        utc_now() - as_utc(eval_db.started_at) if eval_db.started_at else timedelta(0)
    )
    should_have = sum(
        slot.get("sessions", 0) for slot in time_distribution if is_slot_due(slot, current_offset)
    )
    return max(0, should_have - count_total_sessions(eval_db.id, session))


# ---------------------------------------------------------------------------
# Priority
# ---------------------------------------------------------------------------


def calculate_priority(eval_db: IntelligentEvalDB, session: Session) -> int:
    """Smaller value = higher priority. Base 100 minus slot-due, deficit, wait."""
    priority = 100
    if eval_db.plan and eval_db.started_at:
        plan = eval_db.get_plan()
        current_offset = utc_now() - as_utc(eval_db.started_at)
        if any(is_slot_due(s, current_offset) for s in plan.get("time_distribution", [])):
            priority -= 50
    priority -= calculate_session_deficit(eval_db, session) * 10
    if eval_db.started_at:
        wait_min = (utc_now() - as_utc(eval_db.started_at)).total_seconds() / 60
        priority -= min(int(wait_min / 10), 20)
    return max(priority, 1)


# ---------------------------------------------------------------------------
# Attention / severity
# ---------------------------------------------------------------------------


def get_attention_reason(eval_db: IntelligentEvalDB, session: Session) -> Optional[str]:
    """Returns 'slot_due' / 'all_sessions_completed' / None."""
    if not eval_db.plan or not eval_db.started_at:
        return None
    plan = eval_db.get_plan()
    time_distribution = plan.get("time_distribution", [])
    current_offset = utc_now() - as_utc(eval_db.started_at)
    if any(is_slot_due(s, current_offset) for s in time_distribution):
        if calculate_session_deficit(eval_db, session) > 0:
            return "slot_due"
    sessions = session.exec(
        select(IntelligentEvalSessionDB).where(IntelligentEvalSessionDB.eval_id == eval_db.id)
    ).all()
    # ADR-0011：expired/failed 同为会话终态——存在过期会话时也必须触发 analyst，
    # 否则评估永远等不到"全部完成"而卡在 executing
    if sessions and all(s.status in ("completed", "failed", "expired") for s in sessions):
        if len(sessions) >= plan.get("estimated_sessions", 0):
            return "all_sessions_completed"
    return None


def has_high_severity_issues(eval_id: str, session: Session) -> bool:
    completed = session.exec(
        select(IntelligentEvalSessionDB).where(
            IntelligentEvalSessionDB.eval_id == eval_id,
            IntelligentEvalSessionDB.status == "completed",
        )
    ).all()
    for s in completed:
        verdict = s.get_verdict()
        if verdict and verdict.get("severity") == "high":
            return True
    return False