using System.Collections.Concurrent;
using Operations.Service.Application.State;

namespace Operations.Service.Application.Ports;

public sealed class InMemoryRestaurantLifecycleStorePort : IRestaurantLifecycleStorePort
{
    private readonly ConcurrentDictionary<string, PersistedRestaurantLifecycleRecord> orders = new();
    private readonly ConcurrentDictionary<string, ConcurrentQueue<PersistedRestaurantLifecycleEvent>> events = new();

    public InMemoryRestaurantLifecycleStorePort()
    {
        foreach (var record in BuildSeedOrders())
        {
            orders[BuildKey(record.ContextId, record.OrderId)] = record;
        }

        foreach (var record in BuildSeedEvents())
        {
            var queue = events.GetOrAdd(BuildKey(record.ContextId, record.OrderId), static _ => new ConcurrentQueue<PersistedRestaurantLifecycleEvent>());
            queue.Enqueue(record);
        }
    }

    public Task<PersistedRestaurantLifecycleRecord?> GetOrderAsync(string contextId, string orderId, CancellationToken cancellationToken)
    {
        orders.TryGetValue(BuildKey(contextId, orderId), out var record);
        return Task.FromResult(record);
    }

    public Task<IReadOnlyCollection<PersistedRestaurantLifecycleRecord>> ListOrdersAsync(string contextId, CancellationToken cancellationToken)
    {
        var records = orders.Values
            .Where(record => string.Equals(record.ContextId, contextId, StringComparison.Ordinal))
            .OrderByDescending(record => record.UpdatedAtUtc)
            .ToArray();

        return Task.FromResult<IReadOnlyCollection<PersistedRestaurantLifecycleRecord>>(records);
    }

    public Task<IReadOnlyCollection<PersistedRestaurantLifecycleRecord>> ListPayableOrdersAsync(string contextId, CancellationToken cancellationToken)
    {
        var records = orders.Values
            .Where(record => string.Equals(record.ContextId, contextId, StringComparison.Ordinal))
            .Where(record => string.Equals(record.OrderState, "Served", StringComparison.Ordinal))
            .Where(record => string.Equals(record.CheckState, "Open", StringComparison.Ordinal) || string.Equals(record.CheckState, "AwaitingPayment", StringComparison.Ordinal))
            .Where(record => record.OutstandingBalance > 0m)
            .OrderByDescending(record => record.UpdatedAtUtc)
            .ToArray();

        return Task.FromResult<IReadOnlyCollection<PersistedRestaurantLifecycleRecord>>(records);
    }

    public Task UpsertOrderAsync(PersistedRestaurantLifecycleRecord record, CancellationToken cancellationToken)
    {
        orders[BuildKey(record.ContextId, record.OrderId)] = record;
        return Task.CompletedTask;
    }

    public Task<IReadOnlyCollection<PersistedRestaurantLifecycleEvent>> ListEventsAsync(string contextId, string orderId, CancellationToken cancellationToken)
    {
        if (!events.TryGetValue(BuildKey(contextId, orderId), out var queue))
        {
            return Task.FromResult<IReadOnlyCollection<PersistedRestaurantLifecycleEvent>>(Array.Empty<PersistedRestaurantLifecycleEvent>());
        }

        var records = queue.OrderByDescending(record => record.OccurredAtUtc).ToArray();
        return Task.FromResult<IReadOnlyCollection<PersistedRestaurantLifecycleEvent>>(records);
    }

    public Task AppendEventAsync(PersistedRestaurantLifecycleEvent record, CancellationToken cancellationToken)
    {
        var queue = events.GetOrAdd(BuildKey(record.ContextId, record.OrderId), static _ => new ConcurrentQueue<PersistedRestaurantLifecycleEvent>());
        queue.Enqueue(record);
        return Task.CompletedTask;
    }

    private static IReadOnlyCollection<PersistedRestaurantLifecycleRecord> BuildSeedOrders()
    {
        return new[]
        {
            new PersistedRestaurantLifecycleRecord(
                "demo-context",
                "ORD-1001",
                "CHK-1001",
                "T-08",
                "Preparing",
                "Open",
                2,
                true,
                24.00m,
                "USD",
                "customer-orders",
                new[] { "ITEM-101", "ITEM-202" },
                DateTime.UtcNow.AddMinutes(-9)),
            new PersistedRestaurantLifecycleRecord(
                "demo-context",
                "ORD-1002",
                "CHK-1002",
                "T-12",
                "Served",
                "Open",
                4,
                true,
                37.50m,
                "USD",
                "waiter-floor",
                new[] { "ITEM-301", "ITEM-404", "ITEM-405" },
                DateTime.UtcNow.AddMinutes(-4))
        };
    }

    private static IReadOnlyCollection<PersistedRestaurantLifecycleEvent> BuildSeedEvents()
    {
        return new[]
        {
            new PersistedRestaurantLifecycleEvent("demo-context", "ORD-1001", "EVT-1001", "Preparing", "Order ORD-1001 is being prepared at the hot-line station.", DateTime.UtcNow.AddMinutes(-8)),
            new PersistedRestaurantLifecycleEvent("demo-context", "ORD-1002", "EVT-1002", "Served", "Order ORD-1002 was served and is ready for payment.", DateTime.UtcNow.AddMinutes(-3))
        };
    }

    private static string BuildKey(string contextId, string orderId) => $"{contextId}::{orderId}";
}