using System.Diagnostics.CodeAnalysis;
using System.Linq;
using Content.Shared.Chemistry.Components;
using Content.Shared.Chemistry.Reagent;
using Content.Shared.FixedPoint;
using Content.Shared.Kitchen.Components;
using Content.Shared.Stacks;
using Robust.Shared.Containers;
using Robust.Shared.Prototypes;

namespace Content.Shared.Kitchen.EntitySystems;

public abstract partial class MicrowaveSystem
{
    /// <summary>
    /// This event tries to get secret recipes that the microwave might be capable of.
    /// Currently, we only check the microwave itself, but in the future, the user might be able to learn recipes.
    /// </summary>
    [SubscribeLocalEvent]
    private void OnGetSecretRecipes(Entity<FoodRecipeProviderComponent> ent, ref GetSecretRecipesEvent args)
    {
        foreach (var recipeId in ent.Comp.ProvidedRecipes)
        {
            if (ProtoMan.Resolve(recipeId, out var recipeProto))
                args.Recipes.Add(recipeProto);
        }
    }

    /// <summary>
    /// Adds all usable ingredients from a given entity to an ingredient list.
    /// </summary>
    /// <remarks>
    /// The entity itself is a "solid".
    /// If it's a stack, then that stack is its "stacks".
    /// If it has a usable ingredient solution, then the solution's contents are "reagents".
    /// </remarks>
    /// <param name="item">The entity to use as ingredients.</param>
    /// <param name="ingredients">A dictionary of available ingredients to add to.</param>
    private void AddItemIngredients(EntityUid item, ref CookingIngredients ingredients)
    {
        if (TryGetSolidId(item, out var solidId))
            ingredients.AddSolid(solidId.Value);

        if (StackQuery.TryComp(item, out var stack) && TryGetStackId(item, out var stackId))
            ingredients.AddStack(stackId.Value, stack.Count);

        if (TryGetUsableIngredientSolution(item, out _, out var solution))
        {
            foreach (var (reagent, quantity) in solution.Contents)
            {
                ingredients.AddReagent(reagent.Prototype, quantity);
            }
        }
    }

    /// <summary>
    /// Attempts to get a solution from an entity that can be used as viable ingredients in a recipe.
    /// </summary>
    /// <remarks>
    /// For example, a beaker's contents will work, but not the contents of an uncracked egg.
    /// </remarks>
    /// <param name="uid">The entity to attempt to get a usable ingredient solution for.</param>
    /// <param name="solutionEntity">A usable solution entity, if available.</param>
    /// <param name="solution">A usable solution, if available.</param>
    /// <returns>Whether or not a usable ingredient solution was successfully retrieved.</returns>
    private bool TryGetUsableIngredientSolution(EntityUid uid,
        [NotNullWhen(true)] out Entity<SolutionComponent>? solutionEntity,
        [NotNullWhen(true)] out Solution? solution)
    {
        return Solution.TryGetDrainableSolution(uid, out solutionEntity, out solution);
    }

    /// <summary>
    /// Given a dictionary of stacks that need to be spent in a recipe, and the amount of stacks
    /// of a stack we have available, this function gets the number of stacks we need to remove
    /// from the stack entity. It also removes this amount from the remaining stacks dictionary.
    /// </summary>
    /// <param name="availableStacks">How many stacks we have available.</param>
    /// <param name="stackId">The stack ID associated with the stack.</param>
    /// <param name="ingredientsToSpend">How many stacks  still need to be spent in the recipe.</param>
    /// <returns>How many stacks we should remove from the available stack entity.</returns>
    private static int SpendStackQuantity(int availableStacks,
        ProtoId<StackPrototype> stackId,
        CookingIngredients ingredientsToSpend)
    {
        if (!ingredientsToSpend.Stacks.TryGetValue(stackId, out var remaining))
            return 0;

        var spent = Math.Min(availableStacks, remaining);
        ingredientsToSpend.AddStack(stackId, -spent);

        return spent;
    }

    /// <summary>
    /// Given a dictionary of reagents that need to be spent in a recipe, and a quantity of a reagent
    /// that we have available in a solution, this function gets the amount of reagents we need to
    /// remove from the solution. This also removes that amount from the "reagents to spend" dictionary.
    /// </summary>
    /// <param name="availableQuantity">How much reagent we have available.</param>
    /// <param name="reagent">The ID of the reagent we are spending.</param>
    /// <param name="ingredientsToSpend">A dictionary of reagents that still need to be spent.</param>
    /// <returns>How much we should reduce the available reagent volume by.</returns>
    private static FixedPoint2 SpendReagentQuantity(FixedPoint2 availableQuantity,
        ProtoId<ReagentPrototype> reagent,
        CookingIngredients ingredientsToSpend)
    {
        if (!ingredientsToSpend.Reagents.TryGetValue(reagent, out var remaining))
            return 0;

        var spent = FixedPoint2.Min(availableQuantity, remaining);
        ingredientsToSpend.AddReagent(reagent, -spent);

        return spent;
    }

    /// <summary>
    /// Removes a solid ingredient that is used in a recipe, removing it from the dictionary of
    /// remaining solids that still need to be spent in the recipe.
    /// </summary>
    /// <param name="item">The entity to remove.</param>
    /// <param name="itemProto">The solid ID of the ingredient.</param>
    /// <param name="container">The microwave's ingredient storage container.</param>
    /// <param name="ingredientsToSpend">The struct representing ingredients we still need to spend.</param>
    private void SubtractSolidContents(EntityUid item,
        EntProtoId itemProto,
        Container container,
        CookingIngredients ingredientsToSpend)
    {
        if (!ingredientsToSpend.Solids.ContainsKey(itemProto))
            return;

        ingredientsToSpend.AddSolid(itemProto, -1);
        Container.Remove(item, container);
        PredictedQueueDel(item);
    }

    /// <summary>
    /// Given a dictionary of remaining stacks that need to be spent in a recipe, this function
    /// reduces a stack entity's count by however many stacks need to be spent. This also removes the
    /// stack count from our remaining ingredients.
    /// </summary>
    /// <remarks>
    /// If a recipe calls for two stacks of plasma sheets, and you put 5 sheets in the microwave, then
    /// the plasma sheet stack would reduce by 2 (leaving you with 3 remaining), and plasma will
    /// be removed from the remaining stacks dictionary.
    /// </remarks>
    /// <param name="ent">The stack entity.</param>
    /// <param name="ingredientsToSpend">The struct representing ingredients we still need to spend.</param>
    private void SubtractStackContents(Entity<StackComponent?> ent,
        CookingIngredients ingredientsToSpend)
    {
        if (!Resolve(ent.Owner, ref ent.Comp))
            return;

        var stack = ent.Comp;
        var stackId = stack.StackTypeId;
        var startingQuantity = stack.Count;
        var quantityToRemove = SpendStackQuantity(startingQuantity, stackId, ingredientsToSpend);

        _stack.ReduceCount(ent.AsNullable(), quantityToRemove);
    }

    /// <summary>
    /// Given a dictionary of remaining reagents that still need to be spent in a recipe, this function iterates
    /// over a solution's contents and subtracts reagents according to the reagents to spend. This also removes
    /// it from our remaining ingredients.
    /// </summary>
    /// <remarks>
    /// Say you still have 6u mayonnaise remaining, and the solution has 10u mayonnaise, then 6u of
    /// mayonnaise would be removed from the solution, leaving you with 4u left over. Then, mayonnaise
    /// is removed from the dictionary of remaining reagents.
    /// </remarks>
    /// <param name="solutionEntity">The solution entity.</param>
    /// <param name="solution">The solution itself.</param>
    /// <param name="ingredientsToSpend">The struct representing ingredients we still need to spend.</param>
    private void SubtractReagentContents(Entity<SolutionComponent> solutionEntity,
        Solution solution,
        CookingIngredients ingredientsToSpend)
    {
        var reagentsToProcess = ingredientsToSpend.Reagents.Keys.ToList();

        foreach (var reagent in reagentsToProcess)
        {
            var availableQuantity = solution.GetTotalPrototypeQuantity(reagent);
            if (availableQuantity == 0)
                continue;

            var quantityToRemove = SpendReagentQuantity(availableQuantity, reagent, ingredientsToSpend);
            Solution.RemoveReagent(solutionEntity, reagent, quantityToRemove);
        }
    }

    /// <summary>
    /// Attempt to get the solid ID of a given entity.
    /// </summary>
    /// <param name="item">The entity to retrieve a solid ID for.</param>
    /// <param name="solidId">The solid ID of the entity, if any.</param>
    /// <returns>
    /// Whether or not the solid ID was successfully retrieved. False if entity lacks an entity prototype ID.
    /// </returns>
    // TODO: Solids should be tag-based, or something like that. Not prototype-based.
    private bool TryGetSolidId(EntityUid item,
        [NotNullWhen(true)] out EntProtoId? solidId)
    {
        solidId = MetaData(item).EntityPrototype?.ID;
        return solidId != null;
    }

    /// <summary>
    /// Attempt to get the stack ID of a given entity.
    /// </summary>
    /// <param name="ent">The stack entity.</param>
    /// <param name="stack">The stack prototype associated with this entity, if any.</param>
    /// <returns>
    /// Whether or not a stack ID is successfully retrieved. False if this entity is not a stack.
    /// </returns>
    private bool TryGetStackId(Entity<StackComponent?> ent,
        [NotNullWhen(true)] out ProtoId<StackPrototype>? stack)
    {
        stack = null;

        if (!Resolve(ent.Owner, ref ent.Comp, logMissing: false))
            return false;

        stack = ent.Comp.StackTypeId;
        return true;
    }

    /// <summary>
    /// Spend ingredients in the microwave based on a given recipe. This deletes ingredient entities (solids),
    /// subtracts respective stack counts, and removes reagents from ingredient containers (reagents).
    /// </summary>
    /// <remarks>
    /// This function does not check whether or not the contents have *enough* ingredients to
    /// subtract - it simply performs the subtraction.
    /// </remarks>
    /// <param name="ent">The microwave entity.</param>
    /// <param name="portionedRecipe">The recipe used to spend ingredients.</param>
    private void SubtractContents(Entity<MicrowaveComponent> ent, PortionedRecipe portionedRecipe)
    {
        if (!ProtoMan.Resolve(portionedRecipe.Recipe, out var recipe))
            return;

        var ingredientsToSpend = recipe.Ingredients * portionedRecipe.Count;
        var solidsToSpend = ingredientsToSpend.Solids;
        var stacksToSpend = ingredientsToSpend.Stacks;
        var reagentsToSpend = ingredientsToSpend.Reagents;
        var microwave = ent.Comp;
        var microwaveItems = GetMicrowaveContents(ent.AsNullable()).ToArray();

        foreach (var item in microwaveItems)
        {
            if (solidsToSpend.Count > 0
                && TryGetSolidId(item, out var solidId)
                && solidsToSpend.ContainsKey(solidId.Value))
            {
                SubtractSolidContents(item, solidId.Value, microwave.Storage, ingredientsToSpend);
                continue;
                // We're exiting early here; if the solid ingredient is removed from the container,
                // then we shouldn't be attempting to use its stack or reagents.
            }

            if (stacksToSpend.Count > 0
                && StackQuery.TryComp(item, out var stack)
                && TryGetStackId((item, stack), out var stackId)
                && stacksToSpend.ContainsKey(stackId.Value))
            {
                SubtractStackContents((item, stack), ingredientsToSpend);
                if (Deleted(item) || stack.Count <= 0)
                    continue;
                // We're exiting early here - if the stack is empty, then the stack entity
                // is gonna be deleted. Which means we shouldn't be using its reagents.
            }

            if (reagentsToSpend.Count > 0
                && TryGetUsableIngredientSolution(item, out var solutionEntity, out var solution)
                && solution.Volume > 0)
                SubtractReagentContents(solutionEntity.Value, solution, ingredientsToSpend);
        }
    }
}