"""
Portfolio related Pydantic schemas.
"""
from datetime import datetime, date
from decimal import Decimal
from typing import Annotated, Optional, List

from pydantic import BaseModel, Field, PlainSerializer

# Decimal type that serializes as float in JSON responses (not string)
FloatDecimal = Annotated[
    Decimal,
    PlainSerializer(lambda v: float(v), return_type=float, when_used='json'),
]


# Target schemas
class TargetBase(BaseModel):
    ticker: str
    target_ratio: FloatDecimal = Field(..., ge=0, le=100)


class TargetCreate(TargetBase):
    pass


class TargetResponse(TargetBase):
    class Config:
        from_attributes = True


# Holding schemas
class HoldingBase(BaseModel):
    ticker: str
    quantity: int = Field(..., ge=0)
    avg_price: FloatDecimal = Field(..., ge=0)


class HoldingCreate(HoldingBase):
    pass


class HoldingResponse(HoldingBase):
    class Config:
        from_attributes = True


class HoldingWithValue(HoldingResponse):
    """Holding with calculated values."""
    name: str | None = None
    current_price: FloatDecimal | None = None
    value: FloatDecimal | None = None
    current_ratio: FloatDecimal | None = None
    profit_loss: FloatDecimal | None = None
    profit_loss_ratio: FloatDecimal | None = None


# Transaction schemas
class TransactionBase(BaseModel):
    ticker: str
    tx_type: str  # "buy" or "sell"
    quantity: int = Field(..., gt=0)
    price: FloatDecimal = Field(..., gt=0)
    executed_at: datetime
    memo: Optional[str] = None


class TransactionCreate(TransactionBase):
    pass


class TransactionResponse(TransactionBase):
    id: int
    name: str | None = None

    class Config:
        from_attributes = True


# Portfolio schemas
class PortfolioBase(BaseModel):
    name: str = Field(..., min_length=1, max_length=100)
    portfolio_type: str = "general"  # "pension" or "general"


class PortfolioCreate(PortfolioBase):
    pass


class PortfolioUpdate(BaseModel):
    name: Optional[str] = Field(None, min_length=1, max_length=100)
    portfolio_type: Optional[str] = None


class PortfolioResponse(PortfolioBase):
    id: int
    user_id: int
    created_at: datetime
    updated_at: datetime

    class Config:
        from_attributes = True


class PortfolioDetail(PortfolioResponse):
    """Portfolio with targets and holdings."""
    targets: List[TargetResponse] = []
    holdings: List[HoldingWithValue] = []
    total_value: FloatDecimal | None = None
    total_invested: FloatDecimal | None = None
    total_profit_loss: FloatDecimal | None = None
    risk_asset_ratio: FloatDecimal | None = None


# Snapshot schemas
class SnapshotHoldingResponse(BaseModel):
    ticker: str
    name: str | None = None
    quantity: int
    price: FloatDecimal
    value: FloatDecimal
    current_ratio: FloatDecimal

    class Config:
        from_attributes = True


class SnapshotListItem(BaseModel):
    """Snapshot list item (without holdings)."""
    id: int
    portfolio_id: int
    total_value: FloatDecimal
    snapshot_date: date

    class Config:
        from_attributes = True


class SnapshotResponse(BaseModel):
    """Snapshot detail with holdings."""
    id: int
    portfolio_id: int
    total_value: FloatDecimal
    snapshot_date: date
    holdings: List[SnapshotHoldingResponse] = []

    class Config:
        from_attributes = True


class ReturnDataPoint(BaseModel):
    """Single data point for returns chart."""
    date: date
    total_value: FloatDecimal
    daily_return: FloatDecimal | None = None
    cumulative_return: FloatDecimal | None = None
    benchmark_return: FloatDecimal | None = None


class ReturnsResponse(BaseModel):
    """Portfolio returns over time."""
    portfolio_id: int
    start_date: date | None = None
    end_date: date | None = None
    total_return: FloatDecimal | None = None
    cagr: FloatDecimal | None = None
    benchmark_total_return: FloatDecimal | None = None
    data: List[ReturnDataPoint] = []


# Rebalancing schemas
class RebalanceItem(BaseModel):
    ticker: str
    name: str | None = None
    target_ratio: FloatDecimal
    current_ratio: FloatDecimal
    current_quantity: int
    current_value: FloatDecimal
    target_value: FloatDecimal
    diff_value: FloatDecimal
    diff_quantity: int
    action: str  # "buy", "sell", or "hold"


class RebalanceResponse(BaseModel):
    portfolio_id: int
    total_value: FloatDecimal
    items: List[RebalanceItem]


class RebalanceSimulationRequest(BaseModel):
    additional_amount: Decimal = Field(..., gt=0)


class RebalanceSimulationResponse(BaseModel):
    portfolio_id: int
    current_total: FloatDecimal
    additional_amount: FloatDecimal
    new_total: FloatDecimal
    items: List[RebalanceItem]


class RebalanceCalculateRequest(BaseModel):
    """Request for manual rebalance calculation."""
    strategy: str = Field(..., pattern="^(full_rebalance|additional_buy)$")
    prices: Optional[dict[str, Decimal]] = None
    additional_amount: Optional[Decimal] = Field(None, ge=0)


class RebalanceCalculateItem(BaseModel):
    """Extended rebalance item with price change info."""
    ticker: str
    name: str | None = None
    target_ratio: FloatDecimal
    current_ratio: FloatDecimal
    current_quantity: int
    current_value: FloatDecimal
    current_price: FloatDecimal
    target_value: FloatDecimal
    diff_ratio: FloatDecimal
    diff_quantity: int
    action: str  # "buy", "sell", or "hold"
    change_vs_prev_month: FloatDecimal | None = None
    change_vs_start: FloatDecimal | None = None


class RebalanceCalculateResponse(BaseModel):
    """Response for manual rebalance calculation."""
    portfolio_id: int
    total_assets: FloatDecimal
    available_to_buy: FloatDecimal | None = None
    items: List[RebalanceCalculateItem]


# Rebalance apply schemas
class RebalanceApplyItem(BaseModel):
    ticker: str
    action: str  # "buy" or "sell"
    quantity: int = Field(..., gt=0)
    price: FloatDecimal = Field(..., gt=0)


class RebalanceApplyRequest(BaseModel):
    items: List[RebalanceApplyItem]


class RebalanceApplyResponse(BaseModel):
    transactions: List[TransactionResponse]
    holdings_updated: int