using Discord.WebSocket;
using System.Text;

namespace MinecraftDiscordBot;

public class RefinedStorageService : CommandRouter {
    private readonly ITaskWaitSource _taskSource;
    public override string HelpTextPrefix => "!rs ";
    public RefinedStorageService(ITaskWaitSource taskSource) : base() => _taskSource = taskSource;
    public override Task<ResponseType> FallbackHandler(SocketUserMessage message, string method, string[] parameters, CancellationToken ct)
        => Task.FromResult(ResponseType.AsString($"The RS system has no command '{method}'!"));
    public override Task<ResponseType> RootAnswer(SocketUserMessage message, CancellationToken ct)
        => Task.FromResult(ResponseType.AsString("The RS system is online!"));

    private async Task<T> Method<T>(string methodName, Func<string, T> parser, CancellationToken ct, Dictionary<string, object>? parameters = null) {
        var waiter = _taskSource.GetWaiter(parser, ct);
        await _taskSource.Send(new RequestMessage(waiter.ID, methodName, parameters));
        return await waiter.Task;
    }

    private const string CmdEnergyUsage = "energyusage";
    private const string CmdEnergyStorage = "energystorage";
    private const string CmdListItems = "listitems";
    private const string CmdItemName = "itemname";
    private const string CmdListFluids = "listfluids";
    private const string CmdCraftItem = "craft";
    private const string CmdGetItem = "getitem";

    public async Task<int> GetEnergyUsageAsync(CancellationToken ct) => await Method(CmdEnergyUsage, int.Parse, ct);
    public async Task<int> GetEnergyStorageAsync(CancellationToken ct) => await Method(CmdEnergyStorage, int.Parse, ct);
    public async Task<IEnumerable<Item>> ListItemsAsync(CancellationToken ct) => await Method(CmdListItems, ConnectedComputer.Deserialize<IEnumerable<Item>>(), ct);
    public async Task<IEnumerable<Fluid>> ListFluidsAsync(CancellationToken ct) => await Method(CmdListFluids, ConnectedComputer.Deserialize<IEnumerable<Fluid>>(), ct);
    public async Task<Item> GetItemData(string itemid, CancellationToken ct) => await Method(CmdGetItem, ConnectedComputer.Deserialize<Item>(), ct, new() {
        ["name"] = itemid
    });
    public async Task<bool> CraftItem(string itemid, int amount, CancellationToken ct) => await Method(CmdCraftItem, ConnectedComputer.Deserialize<bool>(), ct, new() {
        ["name"] = itemid,
        ["count"] = amount
    });

    private Task<IEnumerable<Item>> FilterItems(SocketUserMessage message, IEnumerable<string> filters, CancellationToken ct)
        => FilterItems(message, filters.Select(ItemFilter.Parse), ct);

    private async Task<IEnumerable<Item>> FilterItems(SocketUserMessage message, IEnumerable<ItemFilter> filters, CancellationToken ct) {
        var items = Items?.ToList().AsEnumerable();
        if (items is null) items = (await RefreshItemList(ct)).ToList();
        foreach (var filter in filters)
            items = items.Where(filter.MatchItem);
        return items.ToList();
    }

    private async Task<List<Item>> RefreshItemList(CancellationToken ct) {
        var response = await ListItemsAsync(ct);
        lock (_itemLock) {
            Items = response.OrderByDescending(i => i.Amount).ToList();
            return Items;
        }
    }

    private List<Item>? Items;
    private readonly object _itemLock = new();

    [CommandHandler(CmdEnergyStorage, HelpText = "Get the amount of energy stored in the RS system.")]
    public async Task<ResponseType> HandleEnergyStorage(SocketUserMessage message, string[] parameters, CancellationToken ct)
        => ResponseType.AsString($"Refined Storage system stores {await GetEnergyStorageAsync(ct)} RF/t");
    [CommandHandler(CmdEnergyUsage, HelpText = "Get the amount of energy used by the RS system.")]
    public async Task<ResponseType> HandleEnergyUsage(SocketUserMessage message, string[] parameters, CancellationToken ct)
        => ResponseType.AsString($"Refined Storage system currently uses {await GetEnergyUsageAsync(ct)} RF/t");
    [CommandHandler(CmdCraftItem, HelpText = "Craft a specific item given an item ID and optionally an amount.")]
    public async Task<ResponseType> HandleCraftItem(SocketUserMessage message, string[] parameters, CancellationToken ct) {
        var amount = 1;
        string itemid;
        if (parameters.Length is 1 or 2) {
            itemid = parameters[0];
            if (parameters.Length is 2)
                if (int.TryParse(parameters[1], out var value)) amount = value;
                else return ResponseType.AsString($"I expected an amount to craft, not '{parameters[1]}'!");
        } else return parameters.Length is < 1
            ? ResponseType.AsString("You have to give me at least an item name!")
            : parameters.Length is > 2
            ? ResponseType.AsString("Yo, those are way too many arguments! I want only item name and maybe an amount!")
            : throw new InvalidOperationException($"Forgot to match parameter length {parameters.Length}!");
        return await CraftItem(itemid, amount, ct)
            ? ResponseType.AsString($"Alright, I'm starting to craft {amount} {itemid}.")
            : ResponseType.AsString($"Nope, that somehow doesn't work!");
    }
    [CommandHandler(CmdGetItem, HelpText = "Get information about a specific item.")]
    public async Task<ResponseType> HandleGetItemData(SocketUserMessage message, string[] parameters, CancellationToken ct) {
        var amount = 1;
        string itemid;
        if (parameters.Length is 1 or 2) {
            itemid = parameters[0];
            if (parameters.Length is 2)
                if (int.TryParse(parameters[1], out var value)) amount = value;
                else return ResponseType.AsString($"I expected an amount to craft, not '{parameters[1]}'!");
        } else return parameters.Length is < 1
            ? ResponseType.AsString("You have to give me at least an item name!")
            : parameters.Length is > 2
            ? ResponseType.AsString("Yo, those are way too many arguments! I want only item name and maybe an amount!")
            : throw new InvalidOperationException($"Forgot to match parameter length {parameters.Length}!");
        var data = await GetItemData(itemid, ct);
        return ResponseType.AsString(data.ToString());
    }
    [CommandHandler(CmdItemName, HelpText = "Filter items by name.")]
    public async Task<ResponseType> HandleItemName(SocketUserMessage message, string[] parameters, CancellationToken ct) {
        if (parameters.Length < 2) return ResponseType.AsString($"Usage: {CmdItemName} filters...");
        else {
            var items = await FilterItems(message, parameters[1..], ct);
            var sb = new StringBuilder();
            sb.AppendLine("Did you mean:");
            sb.AppendJoin("\n", items.Select(i => i.ToString()));
            return ResponseType.AsString(sb.ToString());
        }
    }

    [CommandHandler(CmdListFluids, HelpText = "Gets a list of fluids that are currently stored in the RS system.")]
    public async Task<ResponseType> HandleFluidListing(SocketUserMessage message, string[] parameters, CancellationToken ct) {
        var sb = new StringBuilder();
        sb.Append("The Refined Storage system stores those fluids:");
        var fluids = await ListFluidsAsync(ct);
        foreach (var fluid in fluids.OrderByDescending(i => i.Amount))
            if (fluid.Amount > 10000) sb.AppendFormat("\n{0:n2} B of {1}", fluid.Amount / 1000.0f, fluid.DisplayName);
            else sb.AppendFormat("\n{0:n0} mB of {1}", fluid.Amount, fluid.DisplayName);
        return ResponseType.AsString(sb.ToString());
    }

    [CommandHandler(CmdListItems, HelpText = "Gets a list of items that are currently stored in the RS system.")]
    public async Task<ResponseType> HandleItemListing(SocketUserMessage message, string[] parameters, CancellationToken ct) {
        var sb = new StringBuilder();
        sb.Append("The Refined Storage system currently stores these items:");
        var items = await RefreshItemList(ct);
        lock (_itemLock) {
            int taken = 0;
            foreach (var item in items) {
                if (sb.Length > 500) break;
                sb.AppendFormat("\n{0:n0}x {1}", item.Amount, item.DisplayName);
                taken++;
            }
            if (items.Count > taken) sb.AppendFormat("\nand {0} more items.", items.Skip(taken).Sum(i => i.Amount));
        }
        return ResponseType.AsString(sb.ToString());
    }
}