"""REST API – aktivní EV session a úprava deadline / target SoC."""

from __future__ import annotations

import json
from datetime import date, datetime
from typing import Annotated, Any

import asyncpg
from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel, field_validator

from app.db_json import fetch_json
from app.deps import get_pg_pool

router = APIRouter(prefix="/sites/{site_id}/ev", tags=["ev"])


class EvSessionPatchBody(BaseModel):
    target_soc_pct: float | None = None
    target_deadline: datetime | None = None

    @field_validator("target_soc_pct")
    @classmethod
    def _soc_range(cls, v: float | None) -> float | None:
        if v is not None and not (10 <= v <= 100):
            raise ValueError("target_soc_pct must be between 10 and 100")
        return v


class EvSessionPatchResponse(BaseModel):
    success: bool = True
    session_id: int


@router.get("/sessions/active")
async def get_active_ev_sessions(
    site_id: int,
    pool: Annotated[asyncpg.Pool, Depends(get_pg_pool)],
) -> list[dict[str, Any]]:
    async with pool.acquire() as conn:
        site_ok = await conn.fetchval(
            "SELECT EXISTS(SELECT 1 FROM ems.site WHERE id = $1)", site_id
        )
        if not site_ok:
            raise HTTPException(status_code=404, detail="Site not found")
        rows = await fetch_json(
            conn,
            "select ems.fn_ev_sessions_active($1::int)",
            site_id,
        )
    if not isinstance(rows, list):
        rows = json.loads(rows) if isinstance(rows, str) else []
    return [r for r in rows if isinstance(r, dict)]


@router.patch("/sessions/{session_id}", response_model=EvSessionPatchResponse)
async def patch_ev_session(
    site_id: int,
    session_id: int,
    body: EvSessionPatchBody,
    pool: Annotated[asyncpg.Pool, Depends(get_pg_pool)],
) -> EvSessionPatchResponse:
    async with pool.acquire() as conn:
        site_ok = await conn.fetchval(
            "SELECT EXISTS(SELECT 1 FROM ems.site WHERE id = $1)", site_id
        )
        if not site_ok:
            raise HTTPException(status_code=404, detail="Site not found")

        patch = body.model_dump(exclude_unset=True)
        raw = await fetch_json(
            conn,
            "select ems.fn_ev_session_apply_patch($1::int, $2::int, $3::jsonb)",
            site_id,
            session_id,
            json.dumps(patch),
        )
    if not isinstance(raw, dict):
        raw = json.loads(raw)
    if not raw.get("success"):
        raise HTTPException(status_code=404, detail="Session not found")
    return EvSessionPatchResponse(success=True, session_id=int(raw["session_id"]))


class ArrivalHourItem(BaseModel):
    hour: int
    confidence_pct: int
    samples: int


class ChargerTomorrowArrival(BaseModel):
    tomorrow: list[ArrivalHourItem]


class EvArrivalPredictionResponse(BaseModel):
    insufficient_data: bool
    tomorrow_date: str
    chargers: dict[str, ChargerTomorrowArrival]


@router.get("/arrival-prediction", response_model=EvArrivalPredictionResponse)
async def get_ev_arrival_prediction(
    site_id: int,
    pool: Annotated[asyncpg.Pool, Depends(get_pg_pool)],
) -> EvArrivalPredictionResponse:
    async with pool.acquire() as conn:
        raw = await fetch_json(
            conn,
            "select ems.fn_ev_arrival_prediction_bundle($1::int)",
            site_id,
        )
    if not isinstance(raw, dict):
        raw = json.loads(raw)
    if raw.get("error") == "site_not_found":
        raise HTTPException(status_code=404, detail="Site not found")

    chargers: dict[str, ChargerTomorrowArrival] = {}
    ch_raw = raw.get("chargers") or {}
    if isinstance(ch_raw, dict):
        for code, v in ch_raw.items():
            if not isinstance(v, dict):
                continue
            tlist = v.get("tomorrow") or []
            items: list[ArrivalHourItem] = []
            if isinstance(tlist, list):
                for it in tlist:
                    if not isinstance(it, dict):
                        continue
                    items.append(
                        ArrivalHourItem(
                            hour=int(it.get("hour") or 0),
                            confidence_pct=int(it.get("confidence_pct") or 0),
                            samples=int(it.get("samples") or 0),
                        )
                    )
            chargers[str(code)] = ChargerTomorrowArrival(tomorrow=items)

    td = raw.get("tomorrow_date")
    if isinstance(td, date):
        td_s = td.isoformat()
    elif isinstance(td, datetime):
        td_s = td.date().isoformat()
    else:
        td_s = str(td or "")

    return EvArrivalPredictionResponse(
        insufficient_data=bool(raw.get("insufficient_data")),
        tomorrow_date=td_s,
        chargers=chargers,
    )