from pydantic import BaseModel, Field, field_validator
from datetime import datetime, date
from typing import Optional, List

from app.schemas.category import CategoryResponse
from app.schemas.task import TaskResponse


# ============ GoalStep Schemas ============

class GoalStepBase(BaseModel):
    title: str = Field(..., max_length=200)
    step_type: str = Field(..., pattern="^(phase|milestone)$")
    status: str = Field(default="pending", pattern="^(pending|in_progress|completed)$")
    target_date: Optional[date] = None
    parent_id: Optional[int] = None
    sort_order: int = Field(default=0)


class GoalStepCreate(GoalStepBase):
    pass


class GoalStepUpdate(BaseModel):
    title: Optional[str] = Field(None, max_length=200)
    step_type: Optional[str] = Field(None, pattern="^(phase|milestone)$")
    status: Optional[str] = Field(None, pattern="^(pending|in_progress|completed)$")
    target_date: Optional[date] = None
    parent_id: Optional[int] = None
    sort_order: Optional[int] = None

    @property
    def clearable_fields(self) -> set:
        return {"target_date", "parent_id"}


class GoalStepResponse(GoalStepBase):
    id: int
    goal_id: int
    reached_at: Optional[datetime] = None
    created_at: datetime
    children: List["GoalStepResponse"] = []

    class Config:
        from_attributes = True


# ============ GoalReview Schemas ============

class GoalReviewCreate(BaseModel):
    content: str = Field(..., min_length=1)
    rating: Optional[int] = Field(None, ge=1, le=5)


class GoalReviewResponse(BaseModel):
    id: int
    goal_id: int
    content: str
    rating: Optional[int] = None
    created_at: datetime

    class Config:
        from_attributes = True


# ============ Goal Schemas ============

class GoalBase(BaseModel):
    title: str = Field(..., max_length=200)
    description: Optional[str] = None
    status: str = Field(default="active", pattern="^(active|paused|completed|abandoned)$")
    target_date: Optional[date] = None
    category_id: Optional[int] = None
    color: str = Field(default="#FFB7C5", max_length=20)
    icon: str = Field(default="flag", max_length=50)
    sort_order: int = Field(default=0)


class GoalCreate(GoalBase):
    pass


class GoalUpdate(BaseModel):
    title: Optional[str] = Field(None, max_length=200)
    description: Optional[str] = None
    status: Optional[str] = Field(None, pattern="^(active|paused|completed|abandoned)$")
    target_date: Optional[date] = None
    category_id: Optional[int] = None
    color: Optional[str] = Field(None, max_length=20)
    icon: Optional[str] = Field(None, max_length=50)
    sort_order: Optional[int] = None

    @property
    def clearable_fields(self) -> set:
        return {"description", "target_date", "category_id"}


class GoalListResponse(GoalBase):
    id: int
    progress: int
    completed_at: Optional[datetime] = None
    created_at: datetime
    updated_at: datetime
    category: Optional[CategoryResponse] = None
    total_steps: int = 0
    completed_steps: int = 0

    class Config:
        from_attributes = True


class GoalDetailResponse(GoalListResponse):
    steps: List[GoalStepResponse] = []
    reviews: List[GoalReviewResponse] = []
    tasks: List[TaskResponse] = []


class GoalStatusUpdate(BaseModel):
    status: str = Field(..., pattern="^(active|paused|completed|abandoned)$")