import datetime as dt
import os
from functools import lru_cache
from typing import Any, Literal, Optional

from dotenv import load_dotenv
from fastapi import Depends, FastAPI, Header, HTTPException, Query
from pydantic import BaseModel, Field
from supabase import Client, create_client

load_dotenv()

app = FastAPI(title="NutritionBot API")

MenuMealType = Literal["breakfast", "lunch", "dinner"]
MealLogMealType = Literal["breakfast", "lunch", "dinner", "snack"]
MealLogStatus = Literal["before_only", "completed"]


class HealthResponse(BaseModel):
    status: str


class MenuItem(BaseModel):
    name: str
    calories: Optional[int] = None
    protein_g: Optional[float] = None
    carbs_g: Optional[float] = None
    fat_g: Optional[float] = None


class FoodItem(BaseModel):
    name: str
    estimated_served_g: Optional[float] = None
    estimated_consumed_g: Optional[float] = None
    consumed_ratio: Optional[float] = None
    calories: Optional[int] = None
    protein_g: Optional[float] = None
    carbs_g: Optional[float] = None
    fat_g: Optional[float] = None


class SaveMenuRequest(BaseModel):
    user_id: str
    date: dt.date
    meal_type: MenuMealType
    menu_items: list[MenuItem]
    source: str = "photo_ocr"


class MenuRecord(BaseModel):
    id: str
    created_at: dt.datetime
    user_id: str
    date: dt.date
    meal_type: MenuMealType
    menu_items: list[MenuItem]
    source: Optional[str] = None


class SaveMenuResponse(BaseModel):
    status: str
    menu_id: str


class TodayMenuResponse(BaseModel):
    menus: list[MenuRecord]


class SaveMealRequest(BaseModel):
    user_id: str
    date: dt.date = Field(default_factory=dt.date.today)
    meal_type: MealLogMealType
    menu_id: Optional[str] = None
    status: MealLogStatus = "before_only"
    food_items: list[FoodItem]
    total_calories: int
    total_protein_g: float
    total_carbs_g: float
    total_fat_g: float
    confidence_score: float = Field(default=0.0, ge=0.0, le=1.0)
    analysis_note: Optional[str] = None


class UpdateMealRequest(BaseModel):
    user_id: str
    date: Optional[dt.date] = None
    meal_type: Optional[MealLogMealType] = None
    menu_id: Optional[str] = None
    status: Optional[MealLogStatus] = None
    food_items: Optional[list[FoodItem]] = None
    total_calories: Optional[int] = None
    total_protein_g: Optional[float] = None
    total_carbs_g: Optional[float] = None
    total_fat_g: Optional[float] = None
    confidence_score: Optional[float] = Field(default=None, ge=0.0, le=1.0)
    analysis_note: Optional[str] = None


class MealLogRecord(BaseModel):
    id: str
    created_at: dt.datetime
    user_id: str
    date: dt.date
    meal_type: MealLogMealType
    menu_id: Optional[str] = None
    status: MealLogStatus
    food_items: list[FoodItem]
    total_calories: int
    total_protein_g: float
    total_carbs_g: float
    total_fat_g: float
    confidence_score: Optional[float] = 0.0
    analysis_note: Optional[str] = None


class SaveMealResponse(BaseModel):
    status: str
    meal_id: str


class UpdateMealResponse(BaseModel):
    status: str
    meal_id: str


class MealHistoryResponse(BaseModel):
    meals: list[MealLogRecord]
    count: int


def get_required_env(name: str) -> str:
    value = os.environ.get(name)
    if not value:
        raise RuntimeError(f"Missing required environment variable: {name}")
    return value


@lru_cache
def get_supabase_client() -> Client:
    return create_client(
        get_required_env("SUPABASE_URL"),
        get_required_env("SUPABASE_KEY"),
    )


def get_client() -> Client:
    try:
        return get_supabase_client()
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e)) from e


def verify_api_key(x_api_key: str = Header(..., alias="X-Api-Key")) -> None:
    expected_api_key = os.environ.get("API_KEY")
    if not expected_api_key or x_api_key != expected_api_key:
        raise HTTPException(status_code=401, detail="Unauthorized")


def execute_supabase(query: Any) -> Any:
    try:
        response = query.execute()
        if response is not None:
            error = getattr(response, "error", None)
            if error:
                raise HTTPException(status_code=500, detail=str(error))
        return response
    except HTTPException:
        raise
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e)) from e


def get_first_row_or_500(response: Any, entity_name: str) -> dict[str, Any]:
    rows = getattr(response, "data", None) or []
    if not rows:
        raise HTTPException(
            status_code=500,
            detail=f"No {entity_name} returned from Supabase.",
        )
    return rows[0]


@app.get("/", response_model=HealthResponse)
def healthcheck() -> HealthResponse:
    return HealthResponse(status="ok")


@app.post("/save-menu", response_model=SaveMenuResponse)
def save_menu(
    payload: SaveMenuRequest,
    _: None = Depends(verify_api_key),
) -> SaveMenuResponse:
    supabase = get_client()
    response = execute_supabase(
        supabase.table("school_menus").upsert(
            payload.model_dump(mode="json"),
            on_conflict="user_id,date,meal_type",
        )
    )

    rows = getattr(response, "data", None) or []
    if rows:
        return SaveMenuResponse(status="saved", menu_id=str(rows[0]["id"]))

    lookup = execute_supabase(
        supabase.table("school_menus")
        .select("id")
        .eq("user_id", payload.user_id)
        .eq("date", payload.date.isoformat())
        .eq("meal_type", payload.meal_type)
        .maybe_single()
    )
    if lookup is None or lookup.data is None:
        raise HTTPException(status_code=500, detail="Menu was saved but no row was returned.")
    return SaveMenuResponse(status="saved", menu_id=str(lookup.data["id"]))


@app.get("/today-menu", response_model=TodayMenuResponse)
def get_today_menu(
    user_id: str = Query(...),
    request_date: Optional[dt.date] = Query(default=None, alias="date"),
    meal_type: Optional[MenuMealType] = Query(default=None),
    _: None = Depends(verify_api_key),
) -> TodayMenuResponse:
    supabase = get_client()
    target_date = request_date or dt.date.today()

    query = (
        supabase.table("school_menus")
        .select("*")
        .eq("user_id", user_id)
        .eq("date", target_date.isoformat())
    )
    if meal_type:
        query = query.eq("meal_type", meal_type)

    response = execute_supabase(query.order("meal_type"))
    return TodayMenuResponse(menus=getattr(response, "data", None) or [])


@app.post("/save-meal", response_model=SaveMealResponse)
def save_meal(
    payload: SaveMealRequest,
    _: None = Depends(verify_api_key),
) -> SaveMealResponse:
    supabase = get_client()
    response = execute_supabase(
        supabase.table("meal_logs").insert(payload.model_dump(mode="json"))
    )
    meal_row = get_first_row_or_500(response, "meal log")
    return SaveMealResponse(status="saved", meal_id=str(meal_row["id"]))


@app.patch("/update-meal/{meal_id}", response_model=UpdateMealResponse)
def update_meal(
    meal_id: str,
    payload: UpdateMealRequest,
    _: None = Depends(verify_api_key),
) -> UpdateMealResponse:
    supabase = get_client()
    existing_response = execute_supabase(
        supabase.table("meal_logs").select("*").eq("id", meal_id).maybe_single()
    )
    if existing_response is None or existing_response.data is None:
        raise HTTPException(status_code=404, detail="Meal log not found")

    existing_meal = existing_response.data
    if existing_meal.get("user_id") != payload.user_id:
        raise HTTPException(status_code=403, detail="Forbidden")

    update_data = payload.model_dump(
        mode="json",
        exclude={"user_id"},
        exclude_unset=True,
    )
    if not update_data:
        return UpdateMealResponse(status="updated", meal_id=meal_id)

    update_response = execute_supabase(
        supabase.table("meal_logs")
        .update(update_data)
        .eq("id", meal_id)
        .eq("user_id", payload.user_id)
    )
    get_first_row_or_500(update_response, "updated meal log")
    return UpdateMealResponse(status="updated", meal_id=meal_id)


@app.get("/meal-history", response_model=MealHistoryResponse)
def get_meal_history(
    user_id: str = Query(...),
    days: int = Query(default=7, ge=0),
    limit: int = Query(default=20, ge=1, le=50),
    _: None = Depends(verify_api_key),
) -> MealHistoryResponse:
    supabase = get_client()
    since_date = dt.date.today() - dt.timedelta(days=days)

    response = execute_supabase(
        supabase.table("meal_logs")
        .select("*")
        .eq("user_id", user_id)
        .gte("date", since_date.isoformat())
        .order("created_at", desc=True)
        .limit(limit)
    )
    meals = getattr(response, "data", None) or []
    return MealHistoryResponse(meals=meals, count=len(meals))