Needlework.Net/Needlework.Net.Desktop/ViewModels/OperationViewModel.cs

using Avalonia.Collections;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Messaging;
using Microsoft.OpenApi.Models;
using Needlework.Net.Desktop.Messages;
using System.Collections.Generic;
using System.Linq;
using System.Text.Json;

namespace Needlework.Net.Desktop.ViewModels
{
    public partial class OperationViewModel : ObservableObject
    {
        public string Summary { get; }
        public string Description { get; }
        public string ReturnType { get; }
        public bool IsRequestBody { get; }
        public string? RequestBodyType { get; }
        public IAvaloniaReadOnlyList<PropertyClassViewModel> RequestClasses { get; }
        public IAvaloniaReadOnlyList<PropertyClassViewModel> ResponseClasses { get; }
        public IAvaloniaReadOnlyList<ParameterViewModel> PathParameters { get; }
        public IAvaloniaReadOnlyList<ParameterViewModel> QueryParameters { get; }
        public string? RequestTemplate { get; }

        public OperationViewModel(OpenApiOperation operation)
        {
            Summary = operation.Summary ?? string.Empty;
            Description = operation.Description ?? string.Empty;
            IsRequestBody = operation.RequestBody != null;
            ReturnType = GetReturnType(operation.Responses);
            RequestClasses = GetRequestClasses(operation.RequestBody);
            ResponseClasses = GetResponseClasses(operation.Responses);
            PathParameters = GetParameters(operation.Parameters, ParameterLocation.Path);
            QueryParameters = GetParameters(operation.Parameters, ParameterLocation.Query);
            RequestBodyType = GetRequestBodyType(operation.RequestBody);
            RequestTemplate = GetRequestTemplate(operation.RequestBody);
        }

        private string? GetRequestTemplate(OpenApiRequestBody? requestBody)
        {
            var requestClasses = GetRequestClasses(requestBody);
            if (requestClasses.Count == 0)
            {
                var type = GetRequestBodyType(requestBody);
                if (type == null) return null;
                return GetRequestDefaultValue(type);
            }

            var template = CreateTemplate(requestClasses);
            return JsonSerializer.Serialize(JsonSerializer.Deserialize<object>(string.Join(string.Empty, template)), App.JsonSerializerOptions);
        }

        private List<string> CreateTemplate(AvaloniaList<PropertyClassViewModel> requestClasses)
        {
            if (requestClasses.Count == 0) return [];
            List<string> template = [];
            template.Add("{");

            var rootClass = requestClasses.First();
            if (rootClass.PropertyEnums.Any()) return [rootClass.PropertyEnums.First().Values];
            var propertyFields = rootClass.PropertyFields;
            for (int i = 0; i < propertyFields.Count; i++)
            {
                template.Add($"\"{propertyFields[i].Name}\"");
                template.Add(":");
                template.Add($"#{propertyFields[i].Type}");

                if (i == propertyFields.Count - 1) template.Add("}");
                else template.Add(",");
            }

            for (int i = 0; i < template.Count; i++)
            {
                var type = template[i];
                if (!type.Contains("#")) continue;
                if (requestClasses.Where(c => c.Id == type.Replace("#", string.Empty)).Any())
                {
                    AvaloniaList<PropertyClassViewModel> classes = [.. requestClasses];
                    classes.Remove(rootClass);
                    template[i] = string.Join(string.Empty, CreateTemplate(classes));
                }
                else
                {
                    template[i] = GetRequestDefaultValue(type);
                }
            }

            return template;
        }

        private static string GetRequestDefaultValue(string type)
        {
            var defaultValue = string.Empty;
            if (type.Contains("[]")) defaultValue = "[]";
            else if (type.Contains("string")) defaultValue = "\"\"";
            else if (type.Contains("boolean")) defaultValue = "false";
            else if (type.Contains("integer")) defaultValue = "0";
            else if (type.Contains("double") || type.Contains("float")) defaultValue = "0.0";
            else if (type.Contains("object")) defaultValue = "{}";
            return defaultValue;
        }

        private string? GetRequestBodyType(OpenApiRequestBody? requestBody)
        {
            if (requestBody == null) return null;
            if (requestBody.Content.TryGetValue("application/json", out var media))
            {
                var schema = media.Schema;
                if (schema == null) return null; // Because "PostLolAccountVerificationV1SendDeactivationPin" exists where the media body is empty...
                return GetSchemaType(schema);
            }
            return null;
        }

        private AvaloniaList<ParameterViewModel> GetParameters(IList<OpenApiParameter> parameters, ParameterLocation location)
        {
            var pathParameters = new AvaloniaList<ParameterViewModel>();
            foreach (var parameter in parameters)
            {
                if (parameter.In != location) continue;
                pathParameters.Add(new ParameterViewModel(parameter.Name, GetSchemaType(parameter.Schema), parameter.Required));
            }

            return pathParameters;
        }

        private AvaloniaList<PropertyClassViewModel> GetResponseClasses(OpenApiResponses responses)
        {
            if (responses.TryGetValue("2XX", out var response)
                && response.Content.TryGetValue("application/json", out var media))
            {
                var document = WeakReferenceMessenger.Default.Send(new HostDocumentRequestMessage()).Response;
                var schema = media.Schema;
                AvaloniaList<PropertyClassViewModel> propertyClasses = [];
                WalkSchema(schema, propertyClasses, document);
                return propertyClasses;
            }
            return [];
        }

        private void WalkSchema(OpenApiSchema schema, AvaloniaList<PropertyClassViewModel> propertyClasses, OpenApiDocument document)
        {
            var type = GetSchemaType(schema);
            if (IsComponent(type))
            {
                string componentId = GetComponentId(schema);
                var componentSchema = document.Components.Schemas[componentId];
                var responseClass = new PropertyClassViewModel(componentId, componentSchema.Properties, componentSchema.Enum);

                if (propertyClasses.Where(c => c.Id == componentId).Any()) return; // Avoid adding duplicate schemas in classes
                propertyClasses.Add(responseClass);

                foreach ((var _, var property) in componentSchema.Properties)
                    // Check for self-references like "LolLootLootOddsResponse"
                    // I blame dubble
                    if (IsComponent(GetSchemaType(property)) && componentId != GetComponentId(property))
                        WalkSchema(property, propertyClasses, document);
            }
        }

        private static string GetComponentId(OpenApiSchema schema)
        {
            string componentId;
            if (schema.Reference != null) componentId = schema.Reference.Id;
            else if (schema.Items != null) componentId = schema.Items.Reference.Id;
            else componentId = schema.AdditionalProperties.Reference.Id;
            return componentId;
        }

        private static bool IsComponent(string type)
        {
            return !(type.Contains("object")
                                || type.Contains("array")
                                || type.Contains("bool")
                                || type.Contains("string")
                                || type.Contains("integer")
                                || type.Contains("number"));
        }

        private AvaloniaList<PropertyClassViewModel> GetRequestClasses(OpenApiRequestBody? requestBody)
        {
            if (requestBody == null) return [];
            if (requestBody.Content.TryGetValue("application/json", out var media))
            {
                var document = WeakReferenceMessenger.Default.Send(new HostDocumentRequestMessage()).Response;
                var schema = media.Schema;
                if (schema == null) return [];

                var type = GetSchemaType(media.Schema);
                if (IsComponent(type))
                {
                    var componentId = GetComponentId(schema);
                    var componentSchema = document.Components.Schemas[componentId];
                    AvaloniaList<PropertyClassViewModel> propertyClasses = [];
                    WalkSchema(componentSchema, propertyClasses, document);
                    return propertyClasses;
                }
            }
            return [];
        }

        private string GetReturnType(OpenApiResponses responses)
        {
            if (responses.TryGetValue("2XX", out var response)
                && response.Content.TryGetValue("application/json", out var media))
            {
                var schema = media.Schema;
                return GetSchemaType(schema);
            }
            return "none";
        }

        public static string GetSchemaType(OpenApiSchema schema)
        {
            if (schema.Reference != null) return schema.Reference.Id;
            if (schema.Type == "object" && schema.AdditionalProperties?.Reference != null) return schema.AdditionalProperties.Reference.Id;
            if (schema.Type == "integer" || schema.Type == "number") return $"{schema.Type}:{schema.Format}";
            if (schema.Type == "array" && schema.Items.Reference != null) return $"{schema.Items.Reference.Id}[]";
            if (schema.Type == "array" && (schema.Items.Type == "integer" || schema.Items.Type == "number")) return $"{schema.Items.Type}:{schema.Items.Format}[]";
            if (schema.Type == "array") return $"{schema.Items.Type}[]";
            return schema.Type;
        }
    }
}