using Microsoft.EntityFrameworkCore;
using MealPlanner.Data;
using MealPlanner.Models;

namespace MealPlanner.Services;

public class RecipeService(AppDbContext db, TheMealDbClient mealDbClient)
{
    public async Task<List<Recipe>> GetOwnRecipesAsync(string userId)
    {
        return await db.Recipes
            .Include(r => r.Ingredients)
            .Where(r => r.UserId == userId)
            .OrderByDescending(r => r.CreatedAt)
            .ToListAsync();
    }

    public async Task<Recipe?> GetByIdAsync(Guid id)
    {
        return await db.Recipes
            .Include(r => r.Ingredients)
            .FirstOrDefaultAsync(r => r.Id == id);
    }

    public async Task<Recipe?> GetByIdOrFetchAsync(Guid id)
    {
        var recipe = await GetByIdAsync(id);
        return recipe;
    }

    public async Task<List<Recipe>> SearchAsync(string query, string userId)
    {
        // Local own recipes
        var own = await db.Recipes
            .Include(r => r.Ingredients)
            .Where(r => r.UserId == userId && r.Title.ToLower().Contains(query.ToLower()))
            .ToListAsync();

        // External results
        var external = await mealDbClient.SearchAsync(query);

        // Deduplicate external by ExternalId
        var existingExternalIds = await db.Recipes
            .Where(r => r.Source == RecipeSource.TheMealDb && r.ExternalId != null)
            .Select(r => r.ExternalId!)
            .ToListAsync();

        var newExternal = external
            .Where(r => r.ExternalId != null && !existingExternalIds.Contains(r.ExternalId))
            .ToList();

        return [.. own, .. newExternal];
    }

    public async Task<Recipe> CreateAsync(string userId, Recipe recipe)
    {
        recipe.Id = Guid.NewGuid();
        recipe.UserId = userId;
        recipe.Source = RecipeSource.Own;
        recipe.CreatedAt = DateTime.UtcNow;

        foreach (var ing in recipe.Ingredients)
        {
            ing.Id = Guid.NewGuid();
            ing.RecipeId = recipe.Id;
        }

        db.Recipes.Add(recipe);
        await db.SaveChangesAsync();
        return recipe;
    }

    public async Task<Recipe?> UpdateAsync(Guid id, string userId, Recipe updated)
    {
        var recipe = await db.Recipes
            .Include(r => r.Ingredients)
            .FirstOrDefaultAsync(r => r.Id == id);

        if (recipe is null) return null;
        if (recipe.UserId != userId) throw new UnauthorizedAccessException();

        recipe.Title = updated.Title;
        recipe.Instructions = updated.Instructions;
        recipe.ImageUrl = updated.ImageUrl;

        // Replace ingredients
        db.RecipeIngredients.RemoveRange(recipe.Ingredients);
        recipe.Ingredients = updated.Ingredients.Select(ing => new RecipeIngredient
        {
            Id = Guid.NewGuid(),
            RecipeId = recipe.Id,
            Name = ing.Name,
            Amount = ing.Amount,
            Unit = ing.Unit,
            Category = ing.Category,
        }).ToList();

        await db.SaveChangesAsync();
        return recipe;
    }

    public async Task<bool> DeleteAsync(Guid id, string userId)
    {
        var recipe = await db.Recipes.FirstOrDefaultAsync(r => r.Id == id);
        if (recipe is null) return false;
        if (recipe.UserId != userId) throw new UnauthorizedAccessException();

        db.Recipes.Remove(recipe);
        await db.SaveChangesAsync();
        return true;
    }

    // Save an external recipe to DB so it can be referenced in meal plans
    public async Task<Recipe> EnsurePersistedAsync(Recipe recipe)
    {
        if (recipe.ExternalId is not null)
        {
            var existing = await db.Recipes
                .Include(r => r.Ingredients)
                .FirstOrDefaultAsync(r => r.ExternalId == recipe.ExternalId);
            if (existing is not null) return existing;
        }

        db.Recipes.Add(recipe);
        await db.SaveChangesAsync();
        return recipe;
    }
}