import os
import uuid
import json
from fastapi import APIRouter, Depends, HTTPException, status, UploadFile, File
from sqlalchemy.orm import Session
from typing import List

from database import get_db
from models.product import Product, Category, ProductOption, ProductIngredient, ProductPreferenceSet, ProductPreferenceChoice
from models.order import OrderItem
from models.user import User
from schemas.product import (
    ProductCreate, ProductUpdate, ProductOut, ProductReorderItem,
    CategoryCreate, CategoryUpdate, CategoryOut, CategoryReorderItem,
    PreferenceSetCreate,
)
from routers.deps import get_current_user, require_manager

router = APIRouter()

IMAGE_DIR = "/app/data/product_images"


def _replace_options(db, product, options):
    for opt in product.options:
        db.delete(opt)
    db.flush()
    for opt in options:
        sub_json = json.dumps([s.model_dump() for s in opt.sub_choices]) if opt.sub_choices else None
        db.add(ProductOption(
            product_id=product.id,
            name=opt.name,
            extra_cost=opt.extra_cost,
            sub_choices=sub_json,
        ))


def _replace_ingredients(db, product, ingredients):
    for ing in product.ingredients:
        db.delete(ing)
    db.flush()
    for ing in ingredients:
        db.add(ProductIngredient(product_id=product.id, **ing.model_dump()))


def _replace_preference_sets(db, product, sets: List[PreferenceSetCreate]):
    for ps in product.preference_sets:
        db.delete(ps)
    db.flush()
    for ps in sets:
        shared_json = json.dumps(ps.shared_subset.model_dump()) if ps.shared_subset else None
        new_set = ProductPreferenceSet(
            product_id=product.id,
            name=ps.name,
            shared_subset=shared_json,
        )
        db.add(new_set)
        db.flush()
        created_choices = []
        for ch in ps.choices:
            sub_json = json.dumps([s.model_dump() for s in ch.sub_choices]) if ch.sub_choices else None
            choice = ProductPreferenceChoice(
                set_id=new_set.id,
                name=ch.name,
                extra_cost=ch.extra_cost,
                sub_choices=sub_json,
                disables_subset=ch.disables_subset,
            )
            db.add(choice)
            db.flush()
            created_choices.append(choice)
        if ps.default_choice_index is not None and 0 <= ps.default_choice_index < len(created_choices):
            new_set.default_choice_id = created_choices[ps.default_choice_index].id


# ── Categories ────────────────────────────────────────────────────────────────

@router.get("/categories", response_model=List[CategoryOut])
def list_categories(db: Session = Depends(get_db), user: User = Depends(get_current_user)):
    return db.query(Category).order_by(Category.sort_order).all()


@router.post("/categories", response_model=CategoryOut, status_code=status.HTTP_201_CREATED)
def create_category(body: CategoryCreate, db: Session = Depends(get_db), user: User = Depends(require_manager)):
    max_order = db.query(Category).count()
    cat = Category(name=body.name, color=body.color, sort_order=max_order)
    db.add(cat)
    db.commit()
    db.refresh(cat)
    return cat


@router.put("/categories/reorder", status_code=status.HTTP_204_NO_CONTENT)
def reorder_categories(items: List[CategoryReorderItem], db: Session = Depends(get_db), user: User = Depends(require_manager)):
    for item in items:
        cat = db.query(Category).filter(Category.id == item.id).first()
        if cat:
            cat.sort_order = item.sort_order
    db.commit()


@router.put("/categories/{category_id}", response_model=CategoryOut)
def update_category(category_id: int, body: CategoryUpdate, db: Session = Depends(get_db), user: User = Depends(require_manager)):
    cat = db.query(Category).filter(Category.id == category_id).first()
    if not cat:
        raise HTTPException(status_code=404, detail="Category not found")
    for field, value in body.model_dump(exclude_none=True).items():
        setattr(cat, field, value)
    db.commit()
    db.refresh(cat)
    return cat


@router.delete("/categories/{category_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_category(category_id: int, db: Session = Depends(get_db), user: User = Depends(require_manager)):
    cat = db.query(Category).filter(Category.id == category_id).first()
    if not cat:
        raise HTTPException(status_code=404, detail="Category not found")
    db.delete(cat)
    db.commit()


# ── Products ──────────────────────────────────────────────────────────────────

@router.get("/", response_model=List[ProductOut])
def list_products(all: bool = False, db: Session = Depends(get_db), user: User = Depends(get_current_user)):
    q = db.query(Product)
    if not all or user.role not in ("manager", "sysadmin"):
        q = q.filter(Product.is_available == True)
    return q.order_by(Product.sort_order, Product.id).all()


@router.put("/reorder", status_code=status.HTTP_204_NO_CONTENT)
def reorder_products(items: List[ProductReorderItem], db: Session = Depends(get_db), user: User = Depends(require_manager)):
    for item in items:
        product = db.query(Product).filter(Product.id == item.id).first()
        if product:
            product.sort_order = item.sort_order
    db.commit()


@router.post("/", response_model=ProductOut, status_code=status.HTTP_201_CREATED)
def create_product(body: ProductCreate, db: Session = Depends(get_db), user: User = Depends(require_manager)):
    data = body.model_dump(exclude={"options", "ingredients", "preference_sets"})
    if data.get("sort_order") == 0:
        data["sort_order"] = db.query(Product).count()
    product = Product(**data)
    db.add(product)
    db.flush()
    for opt in body.options:
        sub_json = json.dumps([s.model_dump() for s in opt.sub_choices]) if opt.sub_choices else None
        db.add(ProductOption(product_id=product.id, name=opt.name, extra_cost=opt.extra_cost, sub_choices=sub_json))
    for ing in body.ingredients:
        db.add(ProductIngredient(product_id=product.id, **ing.model_dump()))
    _replace_preference_sets(db, product, body.preference_sets)
    db.commit()
    db.refresh(product)
    return product


@router.put("/{product_id}", response_model=ProductOut)
def update_product(product_id: int, body: ProductUpdate, db: Session = Depends(get_db), user: User = Depends(require_manager)):
    product = db.query(Product).filter(Product.id == product_id).first()
    if not product:
        raise HTTPException(status_code=404, detail="Product not found")
    for field, value in body.model_dump(exclude_none=True, exclude={"options", "ingredients", "preference_sets"}).items():
        setattr(product, field, value)
    if body.options is not None:
        _replace_options(db, product, body.options)
    if body.ingredients is not None:
        _replace_ingredients(db, product, body.ingredients)
    if body.preference_sets is not None:
        _replace_preference_sets(db, product, body.preference_sets)
    db.commit()
    db.refresh(product)
    return product


@router.post("/{product_id}/image", response_model=ProductOut)
async def upload_product_image(product_id: int, file: UploadFile = File(...), db: Session = Depends(get_db), user: User = Depends(require_manager)):
    product = db.query(Product).filter(Product.id == product_id).first()
    if not product:
        raise HTTPException(status_code=404, detail="Product not found")

    if not file.content_type.startswith("image/"):
        raise HTTPException(status_code=400, detail="File must be an image")

    os.makedirs(IMAGE_DIR, exist_ok=True)

    if product.image_url:
        old_path = os.path.join(IMAGE_DIR, os.path.basename(product.image_url))
        if os.path.exists(old_path):
            os.remove(old_path)

    ext = file.filename.rsplit(".", 1)[-1].lower() if "." in file.filename else "jpg"
    filename = f"{product_id}_{uuid.uuid4().hex[:8]}.{ext}"
    filepath = os.path.join(IMAGE_DIR, filename)

    contents = await file.read()
    with open(filepath, "wb") as f:
        f.write(contents)

    product.image_url = f"/static/product_images/{filename}"
    db.commit()
    db.refresh(product)
    return product


@router.delete("/{product_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_product(product_id: int, hard: bool = False, db: Session = Depends(get_db), user: User = Depends(require_manager)):
    product = db.query(Product).filter(Product.id == product_id).first()
    if not product:
        raise HTTPException(status_code=404, detail="Product not found")
    if hard:
        has_orders = db.query(OrderItem).filter(OrderItem.product_id == product_id).first()
        if has_orders:
            raise HTTPException(
                status_code=400,
                detail="Cannot permanently delete a product that appears in past orders. Deactivate it instead."
            )
        db.delete(product)
    else:
        product.is_available = False
    db.commit()