from typing import Any, Literal

from pydantic import BaseModel, Field


class ConceptInput(BaseModel):
    """Stage 1a — input contract. Frozen interface for frontend codegen."""

    parcel_geojson: dict[str, Any] = Field(
        ..., description="GeoJSON Polygon of the parcel (WGS84 / EPSG:4326)"
    )
    housing_class: Literal["econom", "comfort", "business"] = "comfort"
    target_floors: int = Field(9, ge=1, le=30)
    development_type: Literal["spot", "mid_rise", "high_rise"] = "mid_rise"
    land_cost_rub: float | None = Field(
        None, ge=0, description="Optional land cost for financial model"
    )


class TEAP(BaseModel):
    """Технико-экономические показатели."""

    built_area_sqm: float
    total_floor_area_sqm: float
    residential_area_sqm: float
    apartments_count: int
    density: float
    parking_spaces: int


class FinancialModel(BaseModel):
    """Static developer P&L for a concept variant (PR-1, эпик #1881).

    Full static cost cascade + VAT + profit tax → net profit + ROI. NOT a DCF —
    timing/discounting lands in PR-3. VAT is a documented simplification (see
    ``compute_financial`` docstring), not exact НК РФ mechanics.

    The legacy summary fields (``revenue_rub`` / ``cost_rub`` /
    ``gross_margin_rub`` / ``irr``) are kept for backward-compat; the new fields
    expose the full cascade and the net P&L.
    """

    # ── Legacy summary (backward-compat) ───────────────────────────────────────
    revenue_rub: float
    cost_rub: float
    gross_margin_rub: float
    irr: float

    # ── Revenue breakdown ──────────────────────────────────────────────────────
    revenue_residential_rub: float
    revenue_parking_rub: float

    # ── Cost cascade ───────────────────────────────────────────────────────────
    construction_rub: float
    pir_rub: float
    networks_rub: float
    developer_services_rub: float
    contingency_rub: float
    marketing_rub: float
    land_rub: float

    # ── БДР / taxes → net profit ───────────────────────────────────────────────
    vat_rub: float
    profit_before_tax_rub: float
    profit_tax_rub: float
    net_profit_rub: float

    # ── Metrics ────────────────────────────────────────────────────────────────
    roi: float  # net profit / total cost
    margin_pct: float  # net profit / revenue
    irr_is_proxy: bool = True  # frontend caveat: not a real DCF IRR (см. PR-3)


class ConceptVariant(BaseModel):
    strategy: Literal["max_area", "max_insolation", "balanced"]
    buildings_geojson: dict[str, Any]
    teap: TEAP
    financial: FinancialModel


class ConceptOutput(BaseModel):
    variants: list[ConceptVariant]