from fastapi import APIRouter, Depends, HTTPException, Body
from sqlalchemy.orm import Session
from datetime import datetime, timedelta, date
import json

from database import get_db
from schemas import MenuPlanRead, RecipeRead
from models import MenuPlan, Recipe
from services import pantry_service, ai_service
from config import settings

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


def _current_monday():
    today = datetime.utcnow().date()
    return today - timedelta(days=today.weekday())


@router.get("/current")
async def get_current_menu(db: Session = Depends(get_db)):
    """Get menu plan for current week."""
    monday = _current_monday()

    menu = db.query(MenuPlan).filter(MenuPlan.week_start == monday).first()
    if not menu:
        raise HTTPException(status_code=404, detail="No menu plan for current week")
    return MenuPlanRead.from_orm(menu)


@router.post("/generate")
async def generate_menu(request: dict = None, db: Session = Depends(get_db)):
    """Generate a weekly menu using AI."""
    # Parse request body
    week_start = None
    if request and isinstance(request, dict):
        week_start = request.get("week_start")

    # Determine week_start date
    if week_start:
        try:
            if isinstance(week_start, str):
                week_start = datetime.fromisoformat(week_start).date()
        except Exception:
            raise HTTPException(status_code=400, detail="Invalid week_start date")
    else:
        week_start = _current_monday()

    # Build pantry context and generate menu
    try:
        pantry_context = pantry_service.build_pantry_context(db)
        user_notes = request.get("user_notes") if request and isinstance(request, dict) else None
        ai_result = await ai_service.generate_weekly_menu(pantry_context, user_notes)
    except ValueError as e:
        raise HTTPException(status_code=503, detail=str(e))
    except Exception as e:
        raise HTTPException(status_code=503, detail=f"Ollama service error: {str(e)}")

    # Save recipes and build plan list (flat array of IDs)
    recipes_ai = ai_result.get("recipes", [])
    plan_ids = []

    valid_recipes = [r for r in recipes_ai if isinstance(r, dict) and "name" in r]
    all_names = [r["name"] for r in valid_recipes]
    existing = db.query(Recipe).filter(Recipe.name.in_(all_names)).all()
    existing_by_name = {r.name: r for r in existing}

    for recipe_data in valid_recipes:
        meal_name = recipe_data["name"]
        if meal_name in existing_by_name:
            recipe_id = existing_by_name[meal_name].id
        else:
            new_recipe = Recipe(
                name=meal_name,
                meal_type=recipe_data.get("meal_type", "dinner"),
                ingredients=json.dumps(recipe_data.get("ingredients", [])),
                instructions=recipe_data.get("instructions", ""),
                estimated_time_minutes=recipe_data.get("time_minutes", 30),
                servings=recipe_data.get("serves", 2),
                source="ai",
                description=recipe_data.get("description", ""),
            )
            db.add(new_recipe)
            db.flush()
            recipe_id = new_recipe.id
        plan_ids.append(recipe_id)

    ai_notes = ai_result.get("notes", "")
    existing_plan = db.query(MenuPlan).filter(MenuPlan.week_start == week_start).first()
    if existing_plan:
        existing_plan.plan = json.dumps(plan_ids)
        existing_plan.generated_at = datetime.utcnow()
        existing_plan.model_used = settings.model_name
        existing_plan.notes = ai_notes
        menu = existing_plan
    else:
        menu = MenuPlan(
            week_start=week_start,
            plan=json.dumps(plan_ids),
            generated_at=datetime.utcnow(),
            model_used=settings.model_name,
            notes=ai_notes,
        )
        db.add(menu)

    db.commit()
    db.refresh(menu)

    return {
        "menu_plan": MenuPlanRead.from_orm(menu),
        "recipes": recipes_ai,
        "notes": menu.notes or "",
    }


@router.get("")
async def list_menus(db: Session = Depends(get_db)):
    """List all menu plans."""
    menus = db.query(MenuPlan).order_by(MenuPlan.week_start.desc()).all()
    return [MenuPlanRead.from_orm(m) for m in menus]


@router.get("/{week_start}")
async def get_menu(week_start: date, db: Session = Depends(get_db)):
    """Get menu plan for a specific week."""
    menu = db.query(MenuPlan).filter(MenuPlan.week_start == week_start).first()
    if not menu:
        raise HTTPException(status_code=404, detail="Menu plan not found")
    return MenuPlanRead.from_orm(menu)


@router.delete("/current")
async def delete_current_menu(db: Session = Depends(get_db)):
    """Delete the menu plan for the current week."""
    monday = _current_monday()
    menu = db.query(MenuPlan).filter(MenuPlan.week_start == monday).first()
    if not menu:
        raise HTTPException(status_code=404, detail="No menu plan for current week")
    db.delete(menu)
    db.commit()
    return {"status": "deleted"}


@router.delete("/current/recipes/{recipe_id}")
async def remove_recipe_from_menu(recipe_id: int, db: Session = Depends(get_db)):
    """Remove a single recipe from the current week's plan."""
    monday = _current_monday()
    menu = db.query(MenuPlan).filter(MenuPlan.week_start == monday).first()
    if not menu:
        raise HTTPException(status_code=404, detail="No menu plan for current week")

    try:
        plan_ids = json.loads(menu.plan)
    except json.JSONDecodeError:
        raise HTTPException(status_code=500, detail="Invalid menu plan data")

    if recipe_id not in plan_ids:
        raise HTTPException(status_code=404, detail="Recipe not in current menu plan")

    plan_ids.remove(recipe_id)
    menu.plan = json.dumps(plan_ids)
    db.commit()
    return {"status": "removed", "plan": plan_ids}


@router.post("/current/recipes/{recipe_id}/swap")
async def swap_recipe_in_menu(recipe_id: int, request: dict = Body(default={}), db: Session = Depends(get_db)):
    """Swap a single recipe in the current week's plan with a new AI suggestion."""
    monday = _current_monday()
    menu = db.query(MenuPlan).filter(MenuPlan.week_start == monday).first()
    if not menu:
        raise HTTPException(status_code=404, detail="No menu plan for current week")

    try:
        plan_ids = json.loads(menu.plan)
    except json.JSONDecodeError:
        raise HTTPException(status_code=500, detail="Invalid menu plan data")

    # Find the recipe being swapped
    old_recipe = db.query(Recipe).filter(Recipe.id == recipe_id).first()
    if not old_recipe:
        raise HTTPException(status_code=404, detail="Recipe not found")

    meal_type = old_recipe.meal_type

    # Get names of all other recipes in the plan to avoid repeats
    other_ids = [rid for rid in plan_ids if rid != recipe_id]
    other_recipes = db.query(Recipe).filter(Recipe.id.in_(other_ids)).all() if other_ids else []
    existing_names = [r.name for r in other_recipes]

    # Generate replacement
    user_notes = request.get("user_notes") if request else None
    try:
        pantry_context = pantry_service.build_pantry_context(db)
        ai_result = await ai_service.generate_replacement_recipe(meal_type, existing_names, pantry_context, user_notes)
    except ValueError as e:
        raise HTTPException(status_code=503, detail=str(e))
    except Exception as e:
        raise HTTPException(status_code=503, detail=f"Ollama service error: {str(e)}")

    recipe_data = ai_result.get("recipe", {})
    if not recipe_data or "name" not in recipe_data:
        raise HTTPException(status_code=503, detail="AI returned invalid recipe data")

    # Save new recipe
    new_recipe = Recipe(
        name=recipe_data["name"],
        meal_type=recipe_data.get("meal_type", meal_type),
        ingredients=json.dumps(recipe_data.get("ingredients", [])),
        instructions=recipe_data.get("instructions", ""),
        estimated_time_minutes=recipe_data.get("time_minutes", 30),
        servings=recipe_data.get("serves", 2),
        source="ai",
    )
    db.add(new_recipe)
    db.flush()

    # Swap the ID in the plan
    idx = plan_ids.index(recipe_id)
    plan_ids[idx] = new_recipe.id
    menu.plan = json.dumps(plan_ids)
    db.commit()
    db.refresh(new_recipe)

    return {
        "recipe": {
            "id": new_recipe.id,
            "name": new_recipe.name,
            "meal_type": new_recipe.meal_type,
            "ingredients": recipe_data.get("ingredients", []),
            "instructions": new_recipe.instructions,
            "estimated_time_minutes": new_recipe.estimated_time_minutes,
            "servings": new_recipe.servings,
        }
    }


@router.post("/current/recipes")
async def add_recipe_to_menu(request: dict = Body(default={}), db: Session = Depends(get_db)):
    """Generate and add a single recipe by description."""
    description = (request.get("description") or "").strip()
    if not description:
        raise HTTPException(status_code=400, detail="Description is required")

    monday = _current_monday()
    menu_plan = db.query(MenuPlan).filter(MenuPlan.week_start == monday).first()

    # Get existing recipe names to avoid duplicates
    existing_names = []
    if menu_plan:
        try:
            plan_ids = json.loads(menu_plan.plan)
            existing = db.query(Recipe).filter(Recipe.id.in_(plan_ids)).all() if plan_ids else []
            existing_names = [r.name for r in existing]
        except Exception:
            pass

    pantry_context = pantry_service.build_pantry_context(db)

    try:
        result = await ai_service.generate_single_recipe(description, existing_names, pantry_context)
    except ValueError as e:
        raise HTTPException(status_code=503, detail=str(e))
    except Exception as e:
        raise HTTPException(status_code=503, detail=f"Ollama error: {str(e)}")

    recipe_data = result.get("recipe", {})
    if not recipe_data.get("name"):
        raise HTTPException(status_code=503, detail="AI returned invalid recipe")

    new_recipe = Recipe(
        name=recipe_data["name"],
        description=recipe_data.get("description", ""),
        meal_type=recipe_data.get("meal_type", "dinner"),
        ingredients=json.dumps(recipe_data.get("ingredients", [])),
        instructions=recipe_data.get("instructions", ""),
        estimated_time_minutes=recipe_data.get("time_minutes"),
        servings=recipe_data.get("serves", 2),
        source="ai",
    )
    db.add(new_recipe)
    db.flush()

    if menu_plan:
        try:
            plan_ids = json.loads(menu_plan.plan)
        except Exception:
            plan_ids = []
        plan_ids.append(new_recipe.id)
        menu_plan.plan = json.dumps(plan_ids)
    else:
        menu_plan = MenuPlan(
            week_start=monday,
            plan=json.dumps([new_recipe.id]),
        )
        db.add(menu_plan)

    db.commit()
    db.refresh(new_recipe)
    return {"recipe": RecipeRead.from_orm(new_recipe)}


@router.delete("/{id}")
async def delete_menu(id: int, db: Session = Depends(get_db)):
    """Delete a menu plan."""
    menu = db.query(MenuPlan).filter(MenuPlan.id == id).first()
    if not menu:
        raise HTTPException(status_code=404, detail="Menu plan not found")
    db.delete(menu)
    db.commit()
    return {"status": "deleted"}