import { Injectable, NotFoundException } from '@nestjs/common';
import { Prisma } from '@prisma/client';
import { PrismaService } from '../prisma/prisma.service';
import { CreateRecipeDto } from './dto/create-recipe.dto';

@Injectable()
export class RecipesService {
  constructor(private readonly prisma: PrismaService) {}

  async findAll() {
    return this.prisma.recipe.findMany({
      include: {
        ingredients: {
          include: {
            product: true,
          },
        },
      },
      orderBy: {
        name: 'asc',
      },
    });
  }

  async findOne(id: number) {
    const recipe = await this.prisma.recipe.findUnique({
      where: { id },
      include: {
        ingredients: {
          include: {
            product: true,
          },
          orderBy: {
            id: 'asc',
          },
        },
      },
    });

    if (!recipe) {
      throw new NotFoundException(`Recipe with id ${id} not found`);
    }

    return recipe;
  }

  async create(data: CreateRecipeDto) {
    for (const ingredient of data.ingredients) {
      const product = await this.prisma.product.findUnique({
        where: { id: ingredient.productId },
      });

      if (!product) {
        throw new NotFoundException(
          `Product with id ${ingredient.productId} not found`,
        );
      }
    }

    return this.prisma.recipe.create({
      data: {
        name: data.name.trim(),
        description: data.description?.trim() || null,
        instructions: data.instructions?.trim() || null,
        ingredients: {
          create: data.ingredients.map((ingredient) => ({
            productId: ingredient.productId,
            quantity: new Prisma.Decimal(ingredient.quantity),
            unit: ingredient.unit.trim(),
            note: ingredient.note?.trim() || null,
          })),
        },
      },
      include: {
        ingredients: {
          include: {
            product: true,
          },
          orderBy: {
            id: 'asc',
          },
        },
      },
    });
  }

  async getInventoryPreview(id: number) {
    const recipe = await this.prisma.recipe.findUnique({
      where: { id },
      include: {
        ingredients: {
          include: {
            product: true,
          },
          orderBy: {
            id: 'asc',
          },
        },
      },
    });

    if (!recipe) {
      throw new NotFoundException(`Recipe with id ${id} not found`);
    }

    const ingredientPreviews = await Promise.all(
      recipe.ingredients.map(async (ingredient: typeof recipe.ingredients[0]) => {
        const inventoryItems = await this.prisma.inventoryItem.findMany({
          where: {
            productId: ingredient.productId,
          },
          orderBy: {
            createdAt: 'desc',
          },
        });

        const sameUnitItems = inventoryItems.filter(
          (item) => item.unit.trim().toLowerCase() === ingredient.unit.trim().toLowerCase(),
        );

        const availableQuantity = sameUnitItems.reduce(
          (sum, item) => sum + Number(item.quantity),
          0,
        );

        const requiredQuantity = Number(ingredient.quantity);

        let status: 'enough' | 'missing' | 'unit_mismatch';

        if (sameUnitItems.length > 0) {
          status = availableQuantity >= requiredQuantity ? 'enough' : 'missing';
        } else if (inventoryItems.length > 0) {
          status = 'unit_mismatch';
        } else {
          status = 'missing';
        }

        return {
          ingredientId: ingredient.id,
          productId: ingredient.productId,
          productName: ingredient.product.canonicalName || ingredient.product.name,
          requiredQuantity,
          requiredUnit: ingredient.unit,
          note: ingredient.note,
          availableQuantity,
          availableUnit: sameUnitItems.length > 0 ? ingredient.unit : null,
          matchingInventoryItems: sameUnitItems.map((item) => ({
            id: item.id,
            quantity: item.quantity,
            unit: item.unit,
            location: item.location,
          })),
          otherInventoryItems: inventoryItems
            .filter((item) => item.unit.trim().toLowerCase() !== ingredient.unit.trim().toLowerCase())
            .map((item) => ({
              id: item.id,
              quantity: item.quantity,
              unit: item.unit,
              location: item.location,
            })),
          status,
          missingQuantity:
            status === 'missing'
              ? Math.max(0, requiredQuantity - availableQuantity)
              : 0,
        };
      }),
    );

    const summary = {
      totalIngredients: ingredientPreviews.length,
      enoughCount: ingredientPreviews.filter((i: typeof ingredientPreviews[0]) => i.status === 'enough').length,
      missingCount: ingredientPreviews.filter((i: typeof ingredientPreviews[0]) => i.status === 'missing').length,
      unitMismatchCount: ingredientPreviews.filter((i: typeof ingredientPreviews[0]) => i.status === 'unit_mismatch').length,
      canCookExactly:
        ingredientPreviews.every((i: typeof ingredientPreviews[0]) => i.status === 'enough'),
    };

    return {
      recipe: {
        id: recipe.id,
        name: recipe.name,
        description: recipe.description,
      },
      ingredients: ingredientPreviews,
      summary,
    };
  }
}