from fastapi import APIRouter, Depends, Query, status
from sqlalchemy.orm import Session
from typing import Optional, List
from utils.utils import get_db
from . import handler
from .schema import (
    CalculationsessionCreate,
    CalculationsessionUpdate,
    CalculationsessionResponse,
    CalculationResponse,
    CalculationDetailsResponse,
    CalculationInputSchema,
    AmortizationentryCreate,
    AmortizationentryUpdate,
    AmortizationentryResponse,
)

router = APIRouter(prefix="/calculation", tags=["Calculation"])


# CalculationSession Routes
@router.post(
    "/sessions",
    response_model=CalculationsessionResponse,
    status_code=status.HTTP_201_CREATED,
    summary="Create Calculation Session",
    description="Creates a new calculation session for tracking anonymous user activity. Returns 409 if session_id already exists.",
)
def create_calculationsession_route(data: CalculationsessionCreate, db: Session = Depends(get_db)):
    return handler.create_calculationsession(db, data)


@router.get(
    "/sessions",
    response_model=List[CalculationsessionResponse],
    summary="List Calculation Sessions",
    description="Returns a paginated list of calculation sessions. Supports optional filter by session_id.",
)
def list_calculationsessions_route(
    limit: int = Query(20, ge=1, le=100),
    offset: int = Query(0, ge=0),
    session_id: Optional[str] = None,
    db: Session = Depends(get_db),
):
    return handler.list_calculationsessions(db, limit, offset, session_id)


@router.get(
    "/sessions/{id}",
    response_model=CalculationsessionResponse,
    summary="Get Calculation Session",
    description="Returns a single calculation session by ID. Returns 404 if not found.",
)
def get_calculationsession_route(id: str, db: Session = Depends(get_db)):
    return handler.get_calculationsession(db, id)


@router.put(
    "/sessions/{id}",
    response_model=CalculationsessionResponse,
    summary="Update Calculation Session",
    description="Updates an existing calculation session. Only provided fields are updated. Returns 404 if not found.",
)
def update_calculationsession_route(id: str, data: CalculationsessionUpdate, db: Session = Depends(get_db)):
    return handler.update_calculationsession(db, id, data)


@router.delete(
    "/sessions/{id}",
    status_code=status.HTTP_200_OK,
    summary="Delete Calculation Session",
    description="Deletes a calculation session and all associated calculations and amortization entries. Returns 404 if not found.",
)
def delete_calculationsession_route(id: str, db: Session = Depends(get_db)):
    return handler.delete_calculationsession(db, id)


# Calculation Routes
@router.get(
    "/calculations",
    response_model=List[CalculationResponse],
    summary="List Calculations",
    description="Returns a paginated list of calculations. Supports optional filter by session_id.",
)
def list_calculations_route(
    limit: int = Query(20, ge=1, le=100),
    offset: int = Query(0, ge=0),
    session_id: Optional[str] = None,
    db: Session = Depends(get_db),
):
    return handler.list_calculations(db, limit, offset, session_id)


@router.get(
    "/calculations/{id}",
    response_model=CalculationResponse,
    summary="Get Calculation",
    description="Returns a single calculation by ID without amortization entries. Returns 404 if not found.",
)
def get_calculation_route(id: str, db: Session = Depends(get_db)):
    return handler.get_calculation(db, id)


@router.get(
    "/calculations/{id}/details",
    response_model=CalculationDetailsResponse,
    summary="Get Calculation With Details",
    description="Returns a calculation with full amortization schedule including all payment details for each period. Returns 404 if not found.",
)
def get_calculation_details_route(id: str, db: Session = Depends(get_db)):
    return handler.get_calculation_details(db, id)


@router.delete(
    "/calculations/{id}",
    status_code=status.HTTP_200_OK,
    summary="Delete Calculation",
    description="Deletes a calculation and all associated amortization entries. Returns 404 if not found.",
)
def delete_calculation_route(id: str, db: Session = Depends(get_db)):
    return handler.delete_calculation(db, id)


# AmortizationEntry Routes
@router.post(
    "/amortization-entries",
    response_model=AmortizationentryResponse,
    status_code=status.HTTP_201_CREATED,
    summary="Create Amortization Entry",
    description="Creates a new amortization entry for a calculation. Validates that the calculation exists. Returns 404 if calculation not found.",
)
def create_amortization_entry_route(data: AmortizationentryCreate, db: Session = Depends(get_db)):
    return handler.create_amortization_entry(db, data)


@router.get(
    "/amortization-entries",
    response_model=List[AmortizationentryResponse],
    summary="List Amortization Entries",
    description="Returns a paginated list of amortization entries ordered by payment number. Supports optional filter by calculation_id.",
)
def list_amortization_entries_route(
    limit: int = Query(20, ge=1, le=100),
    offset: int = Query(0, ge=0),
    calculation_id: Optional[str] = None,
    db: Session = Depends(get_db),
):
    return handler.list_amortization_entries(db, limit, offset, calculation_id)


@router.get(
    "/amortization-entries/{id}",
    response_model=AmortizationentryResponse,
    summary="Get Amortization Entry",
    description="Returns a single amortization entry by ID. Returns 404 if not found.",
)
def get_amortization_entry_route(id: str, db: Session = Depends(get_db)):
    return handler.get_amortization_entry(db, id)


@router.put(
    "/amortization-entries/{id}",
    response_model=AmortizationentryResponse,
    summary="Update Amortization Entry",
    description="Updates an existing amortization entry. Only provided fields are updated. Returns 404 if not found.",
)
def update_amortization_entry_route(id: str, data: AmortizationentryUpdate, db: Session = Depends(get_db)):
    return handler.update_amortization_entry(db, id, data)


@router.delete(
    "/amortization-entries/{id}",
    status_code=status.HTTP_200_OK,
    summary="Delete Amortization Entry",
    description="Deletes an amortization entry. Returns 404 if not found.",
)
def delete_amortization_entry_route(id: str, db: Session = Depends(get_db)):
    return handler.delete_amortization_entry(db, id)


# Workflow Routes
@router.post(
    "/calculations/calculate",
    response_model=CalculationDetailsResponse,
    status_code=status.HTTP_201_CREATED,
    summary="Perform Loan Calculation",
    description="Performs a complete loan calculation including monthly payment, total interest, and generates full amortization schedule. Validates all inputs against business rules, creates calculation record and all amortization entries in a single transaction, updates session calculation count. Returns 400 for validation errors, 404 if session not found.",
)
def perform_loan_calculation_route(data: CalculationInputSchema, db: Session = Depends(get_db)):
    return handler.perform_loan_calculation(db, data)


@router.post(
    "/sessions/create-or-retrieve",
    response_model=CalculationsessionResponse,
    summary="Create Or Retrieve Session",
    description="Creates a new anonymous session or retrieves existing session by session_id. Updates last_access_at timestamp if session exists. Used for session initialization and tracking.",
)
def create_or_retrieve_session_route(
    session_id: str = Query(..., description="Unique session identifier"),
    user_agent: Optional[str] = Query(None, description="Browser/device information"),
    ip_address: Optional[str] = Query(None, description="User IP address (anonymized)"),
    db: Session = Depends(get_db),
):
    return handler.create_or_retrieve_session(db, session_id, user_agent, ip_address)


@router.get(
    "/sessions/{session_id}/calculations",
    response_model=List[CalculationResponse],
    summary="Get Session Calculations",
    description="Returns all calculations performed in a specific session, ordered by creation date descending. Supports pagination. Returns 404 if session not found.",
)
def get_session_calculations_route(
    session_id: str,
    limit: int = Query(20, ge=1, le=100),
    offset: int = Query(0, ge=0),
    db: Session = Depends(get_db),
):
    return handler.get_session_calculations(db, session_id, limit, offset)


@router.get(
    "/calculations/{id}/amortization",
    response_model=List[AmortizationentryResponse],
    summary="Get Calculation Amortization Schedule",
    description="Returns the complete amortization schedule for a calculation, ordered by payment number. Returns 404 if calculation not found.",
)
def get_calculation_amortization_route(
    id: str,
    limit: int = Query(600, ge=1, le=600),
    offset: int = Query(0, ge=0),
    db: Session = Depends(get_db),
):
    calc = handler.get_calculation(db, id)
    return handler.list_amortization_entries(db, limit, offset, calculation_id=calc.id)