"""Analytics API endpoints for summaries and funnels."""

from __future__ import annotations

from decimal import Decimal

from fastapi import APIRouter, Depends, Query
from pydantic import BaseModel, ConfigDict, field_serializer

from app.api.deps import get_analytics_service, get_organization_context
from app.models.deal import DealStage, DealStatus
from app.services.analytics_service import AnalyticsService, DealSummary, StageBreakdown
from app.services.organization_service import OrganizationContext


def _decimal_to_str(value: Decimal) -> str:
    normalized = value.normalize()
    return format(normalized, "f")


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


class StatusSummaryModel(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    status: DealStatus
    count: int
    amount_sum: Decimal

    @field_serializer("amount_sum")
    def serialize_amount_sum(self, value: Decimal) -> str:
        return _decimal_to_str(value)


class WonStatisticsModel(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    count: int
    amount_sum: Decimal
    average_amount: Decimal

    @field_serializer("amount_sum", "average_amount")
    def serialize_decimal_fields(self, value: Decimal) -> str:
        return _decimal_to_str(value)


class NewDealsWindowModel(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    days: int
    count: int


class DealSummaryResponse(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    by_status: list[StatusSummaryModel]
    won: WonStatisticsModel
    new_deals: NewDealsWindowModel
    total_deals: int


class StageBreakdownModel(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    stage: DealStage
    total: int
    by_status: dict[DealStatus, int]
    conversion_to_next: float | None


class DealFunnelResponse(BaseModel):
    stages: list[StageBreakdownModel]


@router.get("/deals/summary", response_model=DealSummaryResponse)
async def deals_summary(
    days: int = Query(30, ge=1, le=180),
    context: OrganizationContext = Depends(get_organization_context),
    service: AnalyticsService = Depends(get_analytics_service),
) -> DealSummaryResponse:
    """Return aggregated deal statistics for the current organization."""

    summary: DealSummary = await service.get_deal_summary(context.organization_id, days=days)
    return DealSummaryResponse.model_validate(summary)


@router.get("/deals/funnel", response_model=DealFunnelResponse)
async def deals_funnel(
    context: OrganizationContext = Depends(get_organization_context),
    service: AnalyticsService = Depends(get_analytics_service),
) -> DealFunnelResponse:
    """Return funnel breakdown by stages and statuses."""

    breakdowns: list[StageBreakdown] = await service.get_deal_funnel(context.organization_id)
    return DealFunnelResponse(
        stages=[StageBreakdownModel.model_validate(item) for item in breakdowns],
    )