"""Pydantic schemas for the EnergyContract CRUD + versioning API (M6-T04).

Schema hierarchy
----------------
ContractVersionResponse   — single version row (id, dates, values, created_at)
ContractResponse          — contract head (id, name, kind, active, currency, timestamps)
ContractDetailResponse    — contract head + embedded versions list (for GET{id})
ContractListResponse      — paginated list of ContractResponse items
ContractCreate            — POST /api/energy/contracts body
ContractPatch             — PATCH /api/energy/contracts/{id} body (all fields optional)
VersionCreate             — POST /api/energy/contracts/{id}/versions body
ProfilesResponse          — GET /api/energy/profiles response
"""

from __future__ import annotations

from datetime import datetime
from typing import Any

from pydantic import BaseModel, Field


# ---------------------------------------------------------------------------
# Version schemas
# ---------------------------------------------------------------------------


class ContractVersionResponse(BaseModel):
    """Response schema for a single EnergyContractVersion row."""

    id: int
    effective_from: datetime
    effective_to: datetime | None
    values: dict[str, Any]
    created_at: datetime

    model_config = {"from_attributes": True}


# ---------------------------------------------------------------------------
# Contract schemas
# ---------------------------------------------------------------------------


class ContractResponse(BaseModel):
    """Response schema for a single EnergyContract (without embedded versions).

    Used for list responses where embedding all versions would be expensive.
    """

    id: int
    name: str
    kind: str
    active: bool
    currency: str
    created_at: datetime
    updated_at: datetime

    model_config = {"from_attributes": True}


class ContractDetailResponse(BaseModel):
    """Response schema for a single EnergyContract with full version history.

    Returned by GET /api/energy/contracts/{id} and by successful POST / PATCH
    operations where the caller needs to see all version data.
    """

    id: int
    name: str
    kind: str
    active: bool
    currency: str
    created_at: datetime
    updated_at: datetime
    versions: list[ContractVersionResponse]

    model_config = {"from_attributes": True}


class ContractListResponse(BaseModel):
    """Response schema for GET /api/energy/contracts."""

    items: list[ContractResponse]
    total: int


# ---------------------------------------------------------------------------
# Request schemas
# ---------------------------------------------------------------------------


class ContractCreate(BaseModel):
    """Request body for POST /api/energy/contracts.

    ``effective_from`` defaults to the current UTC time if not provided,
    giving the first version an open-ended start from "now".
    ``kind`` is validated at the application layer against the profile registry;
    clients should send ``"manual"`` or ``"tibber"``.
    """

    name: str = Field(..., min_length=1, max_length=255)
    kind: str = Field(..., min_length=1, max_length=32)
    currency: str = Field(default="EUR", min_length=1, max_length=8)
    values: dict[str, Any]
    effective_from: datetime | None = Field(
        default=None,
        description=(
            "UTC datetime from which the first pricing version is effective. "
            "Defaults to the current UTC time when omitted."
        ),
    )


class ContractPatch(BaseModel):
    """Request body for PATCH /api/energy/contracts/{id}.

    All fields are optional.  Sending ``active=true`` activates this contract
    (deactivating all others); ``active=false`` deactivates it without affecting
    other contracts.
    """

    name: str | None = Field(default=None, min_length=1, max_length=255)
    active: bool | None = None


class VersionCreate(BaseModel):
    """Request body for POST /api/energy/contracts/{id}/versions."""

    effective_from: datetime
    values: dict[str, Any]


# ---------------------------------------------------------------------------
# Profile response schemas
# ---------------------------------------------------------------------------


class ProfilesResponse(BaseModel):
    """Response schema for GET /api/energy/profiles.

    ``profiles`` is a list of raw profile dicts as produced by
    ``list_profiles()`` (Pydantic model dumps).  Each entry contains at minimum
    ``kind`` and ``label``; the full nested structure allows the front-end to
    render a type-appropriate form for each pricing profile.
    """

    profiles: list[dict[str, Any]]