from pydantic import BaseModel
from typing import Optional, List
from datetime import date, datetime
from decimal import Decimal
from enum import Enum


class LoadLevel(str, Enum):
    """Workload level classification."""
    NORMAL = "normal"
    WARNING = "warning"
    OVERLOADED = "overloaded"
    UNAVAILABLE = "unavailable"


class TaskWorkloadInfo(BaseModel):
    """Task information for workload detail view."""
    task_id: str
    title: str
    project_id: str
    project_name: str
    due_date: Optional[datetime] = None
    original_estimate: Optional[Decimal] = None
    status: Optional[str] = None


class UserWorkloadSummary(BaseModel):
    """Summary of a user's workload for heatmap display."""
    user_id: str
    user_name: str
    department_id: Optional[str] = None
    department_name: Optional[str] = None
    capacity_hours: Decimal
    allocated_hours: Decimal
    load_percentage: Optional[Decimal] = None
    load_level: LoadLevel
    task_count: int


class WorkloadHeatmapResponse(BaseModel):
    """Response for workload heatmap API."""
    week_start: date
    week_end: date
    users: List[UserWorkloadSummary]


class UserWorkloadDetail(BaseModel):
    """Detailed workload for a specific user."""
    user_id: str
    user_name: str
    week_start: date
    week_end: date
    capacity_hours: Decimal
    allocated_hours: Decimal
    load_percentage: Optional[Decimal] = None
    load_level: LoadLevel
    tasks: List[TaskWorkloadInfo]


class WorkloadSnapshotResponse(BaseModel):
    """Response for workload snapshot."""
    id: str
    user_id: str
    week_start: date
    allocated_hours: Decimal
    capacity_hours: Decimal
    load_percentage: Decimal
    task_count: int
    created_at: datetime
    updated_at: datetime

    class Config:
        from_attributes = True


class CapacityUpdate(BaseModel):
    """Request to update user capacity."""
    capacity: Decimal