using System;
using System.Linq;
using Microsoft.AspNetCore.Mvc.ApiExplorer;
using Microsoft.OpenApi.Models;
using Swashbuckle.AspNetCore.SwaggerGen;

namespace NejCommon.Controllers
{
    public class IApiDescriptionVisibilitySchemaFilter : ISchemaFilter
    {
        List<OpenApiSchema> schemas = new List<OpenApiSchema>();
        public void Apply(OpenApiSchema schema, SchemaFilterContext context)
        {
            RemoveSchemas(context);
            //Get the .net type of the schema
            var type = context.Type;

            //Get attributes that imlement IApiDescriptionVisibilityProvider interface
            var attributes = type.GetCustomAttributes(typeof(IApiDescriptionVisibilityProvider), true).Select(a => a as IApiDescriptionVisibilityProvider);

            //If there are no attributes, then return
            if (!attributes.Any())
                return;

            var ignore = attributes.Any(a => a.IgnoreApi);

            //If the schema is ignored, then remove it from the schema repository
            if (!ignore)
                return;

            schemas.Add(schema);
            RemoveSchemas(context);
        }

        public void RemoveSchemas(SchemaFilterContext context)
        {
            foreach (var schema in schemas)
            {
                var key = context.SchemaRepository.Schemas.FirstOrDefault(k => k.Value == schema).Key;
                if (string.IsNullOrWhiteSpace(key))
                    continue;
                //Console.WriteLine($"Removing schema {key}");
                context.SchemaRepository.Schemas.Remove(key);
            }
        }
    }

    public class OrphanedFilter : IDocumentFilter
    {
        public void Apply(OpenApiDocument swaggerDoc, DocumentFilterContext context)
        {
            // Add all paths parameters, bodies, responses and query parameters to a list
            var ops = swaggerDoc.Paths.SelectMany(p => p.Value.Operations).ToList();

            var Parameters = ops
                    .SelectMany(o => o.Value.Parameters)
                    .Select(x => x.Schema).ToList();
            var requst = ops
                    .Select(o => o.Value.RequestBody)
                    .Where(c => c != null)
                    .SelectMany(x => x.Content)
                    .Select(c => c.Value.Schema).ToList();
            var res = ops
                    .SelectMany(o => o.Value.Responses)
                    .SelectMany(r => r.Value.Content)
                    .Select(c => c.Value.Schema).ToList();

            var usedSchemas = Parameters.Union(requst).Union(res).Distinct();

            /*
                        Console.WriteLine($"Used schemas: {string.Join(", ", swaggerDoc.Components.Parameters)}");

                        var usedSchemas = swaggerDoc.Components.Parameters.Select(x => x.Value.Schema).
                            Union(swaggerDoc.Components.RequestBodies.Select(x => x.Value.Content).SelectMany(x => x.Values).Select(x => x.Schema)).
                            Union(swaggerDoc.Components.Responses.Select(x => x.Value.Content).SelectMany(x => x.Values).Select(x => x.Schema)).
                            Distinct();
                        */
            var schemas = usedSchemas.ToList();

            var currentSchemas = new Dictionary<string, OpenApiSchema>();
            foreach(var sch in schemas){
                ExpandSchemas(context.SchemaRepository, currentSchemas, sch);        
            }

            //Console.WriteLine($"Used schemas: {string.Join(", ", currentSchemas.Keys)}");

            var orphanedSchemas = swaggerDoc.Components.Schemas.Where(x => !currentSchemas.ContainsKey(x.Key)).ToDictionary(x => x.Key, x => x.Value);
            
            //Console.WriteLine($"Unused schemas: {string.Join(", ", orphanedSchemas.Keys)}");
            
            swaggerDoc.Components.Schemas = swaggerDoc.Components.Schemas.Where(x => currentSchemas.ContainsKey(x.Key)).ToDictionary(x => x.Key, x => x.Value);
        }

        public static void ExpandSchemas(SchemaRepository repo, Dictionary<string, OpenApiSchema> currentSchemas, OpenApiSchema schemaToExpand)
        {
            if(schemaToExpand == null)
                return;

            if(schemaToExpand.Type == "array")
                schemaToExpand = schemaToExpand.Items;
            
            var selfRef = schemaToExpand.Reference?.Id;
            var properties = schemaToExpand.Properties.Values.ToList();

            if(selfRef != null && !currentSchemas.ContainsKey(selfRef) && repo.Schemas.ContainsKey(selfRef))
            {
                var sch = repo.Schemas[selfRef];
                currentSchemas.Add(selfRef, sch);

                ExpandSchemas(repo, currentSchemas, sch);
            }
            foreach(var sch in properties)
            {
                ExpandSchemas(repo, currentSchemas, sch); 
            }
        }
    }
}