from decimal import Decimal

from fastapi import APIRouter, Depends
from pydantic import BaseModel, Field

from app.api.deps import get_current_telegram_user
from app.models.user import User
from app.services.loans import generate_annuity_schedule, loan_summary
from app.services.record_parser import ParsedRecord, parse_record_text

router = APIRouter(tags=["parser"])


class ParseRecordRequest(BaseModel):
    text: str = Field(min_length=1, max_length=4000)


class LoanCalculateRequest(BaseModel):
    principal: Decimal = Field(gt=0)
    term_months: int = Field(gt=0, le=600)
    annual_interest_rate: Decimal = Field(ge=0)


@router.post("/parse/record", response_model=ParsedRecord)
async def parse_record(
    payload: ParseRecordRequest,
    current_user: User = Depends(get_current_telegram_user),
) -> ParsedRecord:
    return parse_record_text(payload.text)


@router.post("/loans/calculate")
async def calculate_loan(
    payload: LoanCalculateRequest,
    current_user: User = Depends(get_current_telegram_user),
) -> dict:
    summary = loan_summary(payload.principal, payload.term_months, payload.annual_interest_rate)
    schedule = generate_annuity_schedule(
        principal=payload.principal,
        months=payload.term_months,
        annual_rate=payload.annual_interest_rate,
    )
    return {
        **summary,
        "schedule": [
            {
                "number": row.number,
                "payment": row.payment,
                "principal": row.principal,
                "interest": row.interest,
                "remaining_principal": row.remaining_principal,
            }
            for row in schedule
        ],
    }