using System.Text.Json;
using MealPlanner.Models;

namespace MealPlanner.Services;

public class TheMealDbClient(HttpClient httpClient)
{
    private const string BaseUrl = "https://www.themealdb.com/api/json/v1/1/";

    public async Task<Recipe?> GetRandomAsync()
    {
        var response = await httpClient.GetAsync($"{BaseUrl}random.php");
        if (!response.IsSuccessStatusCode) return null;

        var json = await response.Content.ReadAsStringAsync();
        var meals = ParseMeals(json);
        return meals.FirstOrDefault();
    }

    public async Task<List<Recipe>> SearchAsync(string query)
    {
        var response = await httpClient.GetAsync($"{BaseUrl}search.php?s={Uri.EscapeDataString(query)}");
        if (!response.IsSuccessStatusCode) return [];

        var json = await response.Content.ReadAsStringAsync();
        return ParseMeals(json);
    }

    public async Task<Recipe?> GetByIdAsync(string id)
    {
        var response = await httpClient.GetAsync($"{BaseUrl}lookup.php?i={id}");
        if (!response.IsSuccessStatusCode) return null;

        var json = await response.Content.ReadAsStringAsync();
        return ParseMeals(json).FirstOrDefault();
    }

    private static List<Recipe> ParseMeals(string json)
    {
        var result = new List<Recipe>();

        using var doc = JsonDocument.Parse(json);
        if (!doc.RootElement.TryGetProperty("meals", out var mealsEl) || mealsEl.ValueKind == JsonValueKind.Null)
            return result;

        foreach (var meal in mealsEl.EnumerateArray())
        {
            var recipe = MapMeal(meal);
            if (recipe is not null)
                result.Add(recipe);
        }

        return result;
    }

    private static Recipe? MapMeal(JsonElement meal)
    {
        var id = meal.GetStringOrNull("idMeal");
        var title = meal.GetStringOrNull("strMeal");
        if (id is null || title is null) return null;

        var recipe = new Recipe
        {
            Id = Guid.NewGuid(),
            ExternalId = id,
            Title = title,
            Instructions = meal.GetStringOrNull("strInstructions") ?? "",
            ImageUrl = meal.GetStringOrNull("strMealThumb"),
            Source = RecipeSource.TheMealDb,
            CreatedAt = DateTime.UtcNow,
        };

        // Parse strIngredient1-20 / strMeasure1-20
        for (int i = 1; i <= 20; i++)
        {
            var name = meal.GetStringOrNull($"strIngredient{i}");
            var measure = meal.GetStringOrNull($"strMeasure{i}");

            if (string.IsNullOrWhiteSpace(name)) continue;

            var ingredient = new RecipeIngredient
            {
                Id = Guid.NewGuid(),
                RecipeId = recipe.Id,
                Name = name.Trim(),
            };

            if (!string.IsNullOrWhiteSpace(measure))
            {
                ParseMeasure(measure.Trim(), out var amount, out var unit);
                ingredient.Amount = amount;
                ingredient.Unit = unit;
            }

            recipe.Ingredients.Add(ingredient);
        }

        GermanTranslator.TranslateRecipe(recipe);
        return recipe;
    }

    private static void ParseMeasure(string measure, out decimal? amount, out string? unit)
    {
        amount = null;
        unit = null;

        if (string.IsNullOrWhiteSpace(measure)) return;

        // Try to extract leading number
        var parts = measure.Trim().Split(' ', 2);
        if (parts.Length > 0 && decimal.TryParse(parts[0], System.Globalization.NumberStyles.Any,
            System.Globalization.CultureInfo.InvariantCulture, out var parsed))
        {
            amount = parsed;
            unit = parts.Length > 1 ? parts[1].Trim() : null;
        }
        else
        {
            unit = measure;
        }
    }
}

file static class JsonElementExtensions
{
    public static string? GetStringOrNull(this JsonElement el, string propertyName)
    {
        if (el.TryGetProperty(propertyName, out var prop) && prop.ValueKind == JsonValueKind.String)
        {
            var val = prop.GetString();
            return string.IsNullOrWhiteSpace(val) ? null : val;
        }
        return null;
    }
}