using System.Security.Cryptography;
using System.Text.Json;
using Microsoft.EntityFrameworkCore;
using RadicadeServer.DB;
using RadicadeServer.Extensions;

namespace RadicadeServer.API.Rooms
{
	internal static class RoomEconomyPayload
	{
		private const string RawKey = "RoomEconomyPayload.Raw";

		public static async Task<JsonElement?> ReadBodyAsync(HttpRequest request)
		{
			if (request.HasFormContentType)
			{
				try
				{
					var form = await request.ReadFormAsync();
					if (form.Count > 0)
					{
						var fields = new Dictionary<string, object?>();
						foreach (var field in form)
							fields[field.Key] = field.Value.ToString();
						foreach (var file in form.Files)
							fields[file.Name] = file.FileName;
						return JsonSerializer.SerializeToElement(fields);
					}
				}
				catch (Exception ex)
				{
					request.HttpContext.Items[RawKey] = $"<form body could not be read: {ex.Message}>";
				}
			}

			string raw;
			using (var reader = new StreamReader(request.Body))
				raw = await reader.ReadToEndAsync();

			var text = raw.TrimStart('\uFEFF', ' ', '\t', '\r', '\n');
			if (text.Length == 0) return null;

			if (text[0] is '{' or '[')
			{
				try
				{
					using var doc = JsonDocument.Parse(text);
					return doc.RootElement.Clone();
				}
				catch (JsonException)
				{
				}
			}

			var pairs = ParsePairs(raw);
			if (pairs.Count > 0)
			{
				request.HttpContext.Items[RawKey] = raw;
				return JsonSerializer.SerializeToElement(pairs);
			}

			request.HttpContext.Items[RawKey] = raw;
			return null;
		}

		public static string RawBody(HttpRequest request) =>
			request.HttpContext.Items.TryGetValue(RawKey, out var raw) ? raw as string ?? "" : "";

		public static JsonElement? Value(JsonElement? body, params string[] names)
		{
			if (body == null) return null;

			var stack = new Stack<JsonElement>();
			stack.Push(body.Value);
			var visited = 0;

			while (stack.Count > 0 && visited++ < 2000)
			{
				var element = stack.Pop();
				if (element.ValueKind == JsonValueKind.Array)
				{
					foreach (var item in element.EnumerateArray()) stack.Push(item);
					continue;
				}
				if (element.ValueKind != JsonValueKind.Object) continue;

				foreach (var property in element.EnumerateObject())
				{
					if (property.Value.ValueKind is JsonValueKind.Object or JsonValueKind.Array)
					{
						stack.Push(property.Value);
						continue;
					}
					if (Matches(property.Name, names)) return property.Value;
				}
			}

			return null;
		}

		public static string? String(JsonElement? body, params string[] names)
		{
			var value = Value(body, names);
			if (value == null) return null;
			if (value.Value.ValueKind == JsonValueKind.String) return value.Value.GetString();
			if (value.Value.ValueKind is JsonValueKind.Number or JsonValueKind.True or JsonValueKind.False)
				return value.Value.ToString();
			return null;
		}

		public static long? Long(JsonElement? body, params string[] names)
		{
			var value = Value(body, names);
			if (value == null) return null;
			if (value.Value.ValueKind == JsonValueKind.Number)
			{
				if (value.Value.TryGetInt64(out var number)) return number;
				if (value.Value.TryGetDouble(out var real)) return (long)real;
			}
			if (value.Value.ValueKind == JsonValueKind.String && long.TryParse(value.Value.GetString(), out var parsed))
				return parsed;
			return null;
		}

		public static bool? Bool(JsonElement? body, params string[] names)
		{
			var value = Value(body, names);
			if (value == null) return null;
			if (value.Value.ValueKind == JsonValueKind.True) return true;
			if (value.Value.ValueKind == JsonValueKind.False) return false;
			return null;
		}

		public static long? LongFromRequest(HttpRequest request, params string[] names)
		{
			foreach (var pair in request.Query)
			{
				if (!Matches(pair.Key, names)) continue;
				if (long.TryParse(pair.Value.FirstOrDefault(), out var fromQuery)) return fromQuery;
			}
			foreach (var pair in request.RouteValues)
			{
				if (!Matches(pair.Key, names)) continue;
				if (long.TryParse(pair.Value?.ToString(), out var fromRoute)) return fromRoute;
			}
			return null;
		}

		public static Dictionary<string, object?> Fields(JsonElement? body)
		{
			var fields = new Dictionary<string, object?>(StringComparer.OrdinalIgnoreCase);
			if (body == null || body.Value.ValueKind != JsonValueKind.Object) return fields;

			foreach (var property in body.Value.EnumerateObject())
			{
				fields[property.Name] = property.Value.ValueKind switch
				{
					JsonValueKind.String => property.Value.GetString(),
					JsonValueKind.Number => property.Value.TryGetInt64(out var number) ? number : property.Value.GetDouble(),
					JsonValueKind.True => true,
					JsonValueKind.False => false,
					JsonValueKind.Null => null,
					_ => property.Value.Clone()
				};
			}

			return fields;
		}

		public static async Task<long?> RoomIdAsync(RecDBContext db, HttpRequest request, JsonElement? body, params string[] names)
		{
			var roomId = Long(body, names) ?? LongFromRequest(request, names);
			if (roomId is > 0) return roomId;

			var accountId = request.HttpContext.User.GetUserId();
			if (accountId is not > 0) return null;
			var presence = await db.Presences.AsNoTracking()
				.FirstOrDefaultAsync(item => item.playerId == accountId.Value);
			if (presence?.roomInstance is not > 0) return null;
			return await db.RoomInstances.AsNoTracking()
				.Where(instance => instance.roomInstanceId == presence.roomInstance.Value)
				.Select(instance => (long?)instance.roomId)
				.FirstOrDefaultAsync();
		}

		public static string NewId()
		{
			var bytes = RandomNumberGenerator.GetBytes(16);
			return Convert.ToBase64String(bytes).Replace('+', '-').Replace('/', '_').TrimEnd('=');
		}

		private static Dictionary<string, object?> ParsePairs(string raw)
		{
			var pairs = new Dictionary<string, object?>();
			foreach (var pair in raw.Split('&', StringSplitOptions.RemoveEmptyEntries))
			{
				var at = pair.IndexOf('=');
				var key = at < 0 ? pair : pair[..at];
				var value = at < 0 ? "" : pair[(at + 1)..];
				key = key.Trim();
				if (key.Length == 0) continue;

				try
				{
					pairs[Uri.UnescapeDataString(key.Replace('+', ' '))] =
						Uri.UnescapeDataString(value.Replace('+', ' '));
				}
				catch (UriFormatException)
				{
					pairs[key] = value;
				}
			}
			return pairs;
		}

		private static bool Matches(string name, string[] names)
		{
			foreach (var wanted in names)
			{
				if (string.Equals(Normalize(name), Normalize(wanted), StringComparison.Ordinal)) return true;
			}
			return false;
		}

		private static string Normalize(string name) =>
			string.Concat(name.Where(char.IsLetterOrDigit)).ToLowerInvariant();
	}
}