from pydantic import BaseModel, ConfigDict, Field
from datetime import datetime, date
from typing import Optional, List, Literal
from app.schemas.task_comment import TaskCommentResponse
from app.schemas.project_task_assignment import TaskAssignmentResponse

TaskStatus = Literal["pending", "in_progress", "completed", "blocked", "review", "on_hold"]
TaskPriority = Literal["none", "low", "medium", "high"]


class ProjectTaskCreate(BaseModel):
    model_config = ConfigDict(extra="forbid")

    title: str = Field(min_length=1, max_length=255)
    description: Optional[str] = Field(None, max_length=5000)
    status: TaskStatus = "pending"
    priority: TaskPriority = "medium"
    due_date: Optional[date] = None
    person_id: Optional[int] = None
    sort_order: int = 0
    parent_task_id: Optional[int] = None


class ProjectTaskUpdate(BaseModel):
    model_config = ConfigDict(extra="forbid")

    title: Optional[str] = Field(None, min_length=1, max_length=255)
    description: Optional[str] = Field(None, max_length=5000)
    status: Optional[TaskStatus] = None
    priority: Optional[TaskPriority] = None
    due_date: Optional[date] = None
    person_id: Optional[int] = None
    sort_order: Optional[int] = None
    version: Optional[int] = None  # For optimistic locking


class ProjectTaskResponse(BaseModel):
    id: int
    project_id: int
    parent_task_id: Optional[int] = None
    title: str
    description: Optional[str]
    status: str
    priority: str
    due_date: Optional[date]
    person_id: Optional[int]
    sort_order: int
    version: int = 1
    created_at: datetime
    updated_at: datetime
    subtasks: List["ProjectTaskResponse"] = []
    comments: List[TaskCommentResponse] = []
    assignments: List[TaskAssignmentResponse] = []

    model_config = ConfigDict(from_attributes=True)


ProjectTaskResponse.model_rebuild()