from pydantic import BaseModel, ConfigDict, Field
from typing import Optional, List, Literal
from datetime import datetime
from decimal import Decimal


TxnType = Literal["receipt", "payment"]
PartnerType = Literal["customer", "supplier"]
OrderType = Literal["sales", "purchase"]
TxnStatus = Literal["confirmed", "voided"]


class FinanceAllocationCreate(BaseModel):
    order_type: OrderType
    order_id: int
    allocated_amount: Decimal = Field(gt=0)


class FinanceTransactionCreate(BaseModel):
    amount: Decimal = Field(gt=0)
    txn_date: Optional[datetime] = None
    method: str = "bank"
    account_name: Optional[str] = None
    remark: Optional[str] = None
    allocations: List[FinanceAllocationCreate]


class ReceiptCreate(FinanceTransactionCreate):
    customer_id: int


class PaymentCreate(FinanceTransactionCreate):
    supplier_id: int


class FinanceAllocationResponse(BaseModel):
    id: int
    order_type: str
    order_id: int
    allocated_amount: Decimal

    model_config = ConfigDict(from_attributes=True)


class FinanceTransactionResponse(BaseModel):
    id: int
    txn_no: str
    txn_type: TxnType
    partner_type: PartnerType
    partner_id: int
    partner_name: Optional[str] = None
    amount: Decimal
    txn_date: datetime
    method: str
    account_name: Optional[str]
    status: TxnStatus
    remark: Optional[str]
    created_at: datetime
    allocations: List[FinanceAllocationResponse] = []

    model_config = ConfigDict(from_attributes=True)


class FinanceSummaryResponse(BaseModel):
    receivable_total: Decimal
    payable_total: Decimal
    monthly_receipt_total: Decimal
    monthly_payment_total: Decimal
    selected_year: int
    selected_quarter: Optional[int] = None
    period_label: str
    period_receipt_total: Decimal = Decimal("0")
    period_payment_total: Decimal = Decimal("0")
    overdue_receivable_count: int = 0
    overdue_payable_count: int = 0


class ReceivableItemResponse(BaseModel):
    order_id: int
    order_no: str
    customer_id: int
    customer_name: str
    order_date: datetime
    total_amount: Decimal
    received_amount: Decimal
    receivable_amount: Decimal
    status: str


class PayableItemResponse(BaseModel):
    order_id: int
    order_no: str
    supplier_id: int
    supplier_name: str
    order_date: datetime
    total_amount: Decimal
    paid_amount: Decimal
    payable_amount: Decimal
    status: str


class PartnerStatementItemResponse(BaseModel):
    partner_id: int
    partner_name: str
    order_count: int
    transaction_count: int
    order_total: Decimal
    settled_total: Decimal
    transaction_total: Decimal
    outstanding_total: Decimal
    period_year: int
    period_quarter: Optional[int] = None


class FinancePartnerStatementResponse(BaseModel):
    partner_type: PartnerType
    year: int
    quarter: Optional[int] = None
    period_label: str
    order_total: Decimal
    settled_total: Decimal
    transaction_total: Decimal
    outstanding_total: Decimal
    items: List[PartnerStatementItemResponse] = []


class PartnerProductStatementItemResponse(BaseModel):
    partner_id: int
    partner_name: str
    product_id: int
    product_sku: Optional[str] = None
    product_name: str
    order_count: int
    order_quantity: Decimal
    order_amount: Decimal
    settled_amount: Decimal
    outstanding_amount: Decimal
    period_year: int
    period_quarter: Optional[int] = None


class FinancePartnerProductStatementResponse(BaseModel):
    partner_type: PartnerType
    year: int
    quarter: Optional[int] = None
    period_label: str
    partner_id: Optional[int] = None
    order_amount_total: Decimal
    settled_amount_total: Decimal
    outstanding_amount_total: Decimal
    items: List[PartnerProductStatementItemResponse] = []