using System;
using System.Collections.Generic;
using System.Linq;
using isnd.Controllers;
using isnd.Data;
using isnd.Data.Catalog;
using isnd.Entities;
using isnd.Interfaces;
using isnd.ViewModels;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Options;
using NuGet.Versioning;
using Unleash;

namespace isnd.Services
{
   

    public class PackageManager : IPackageManager
    {
        ApplicationDbContext dbContext;
        public PackageManager(ApplicationDbContext dbContext, IOptions<IsndSettings> pmConfigOptions)
        {
            this.dbContext = dbContext;
            CurrentCatalogIndex = GetCatalogIndex();
            this.pmConfigOptions = pmConfigOptions.Value;
        }


        public PackageIndexViewModel SearchByName(string query,
             int skip, int take, bool prerelease = false,
             string packageType = null)
        {

            var scope = dbContext.Packages
                .Include(p => p.Versions)
                .Where(
                    p => (CamelCaseMatch(p.Id, query) || SeparatedByMinusMatch(p.Id, query))
                    && (prerelease || p.Versions.Any(v => !v.IsPrerelease))
                    && (packageType == null || p.Versions.Any(v => v.Type == packageType))
                );
            var total = scope.Count();
            var pkgs = scope.Skip(skip).Take(take).ToArray();

            return new PackageIndexViewModel
            {
                query = query,
                totalHits = total,
                data = pkgs
            };
        }
        const int maxPageLen = 512;

        public CatalogIndex GenerateCatalogIndex(string commitId)
        {

            var root = "/index.json";


            var catalog = new CatalogIndex
            {
                CommitId = commitId,
                CommitTimeStamp = DateTime.Now
            };
            var scope = dbContext.Packages.Where(p => p.Public)
                .OrderBy(p => p.CommitTimeStamp);
            catalog.Items = new List<PageRef>();

            int pagecount = (int)(scope.Count() / maxPageLen);

            for (int pagelen = 0, pagenum = 0; pagelen < pagecount; pagenum++)
            {
                Page p = new Page
                {

                };

            }
            dbContext.Packages.Where(p => p.Public)
                .OrderBy(p => p.CommitTimeStamp);
            return catalog;

        }
        public Page CatalogPage()
        {
            var scope = dbContext.Packages
                .Where(P => P.Versions.Count > 0)
                .Select(
                    p => new PackageRef { Id = p.Id, Version = p.Versions.Max().FullString });

            return new Page
            {
                Items = scope.ToList()
            };
        }
        public void PublishCatalog()
        {

        }

        public AutoCompleteResult AutoComplete(string id,
             int skip, int take, bool prerelease = false,
             string packageType = null)
        {
            var scope = dbContext.PackageVersions.Where(
                         v => v.PackageId == id
                            && (prerelease || !v.IsPrerelease)
                            && (packageType == null || v.Type == packageType)
                     )
                     .OrderBy(v => v.FullString);
            return new AutoCompleteResult
            {
                totalHits = scope.Count(),
                data = scope.Select(v => v.FullString)
                     .Skip(skip).Take(take).ToArray()
            };
        }

        // TODO stocker MetaData plutôt que FullString en base,
        // et en profiter pour corriger ce listing
        public string[] GetVersions(
            string id,
            NuGetVersion parsedVersion,
            bool prerelease = false,
            string packageType = null,
            int skip = 0,
            int take = 25)
        {
            return dbContext.PackageVersions.Where(
                         v => v.PackageId == id
                            && (prerelease || !v.IsPrerelease)
                            && (packageType == null || v.Type == packageType)
                            && (parsedVersion.CompareTo(new SemanticVersion(v.Major, v.Minor, v.Patch)) < 0)
                     )
                     .OrderBy(v => v.FullString)
                     .Select(v => v.FullString)
                     .Skip(skip).Take(take).ToArray();
        }

        public static CatalogIndex CurrentCatalogIndex { get; protected set; }

        private IsndSettings pmConfigOptions;

        public virtual CatalogIndex GetCatalogIndex()
        {
            if (CurrentCatalogIndex == null)
            {
                LoadCatalogFromDb();
            }
            return CurrentCatalogIndex;
        }
        void LoadCatalogFromDb()
        {
            dbContext.Commits.OrderBy(c => c.TimeStamp);
            throw new NotImplementedException();
        }

        protected static bool CamelCaseMatch(string id, string query)
        {
            // Assert.False (q==null);
            if (string.IsNullOrEmpty(query)) return true;

            while (id.Length > 0)
            {
                int i = 0;
                while (id.Length > i && char.IsLower(id[i])) i++;
                if (i == 0) break;
                id = id.Substring(i);
                if (id.StartsWith(query, System.StringComparison.OrdinalIgnoreCase)) return true;
            }
            return false;
        }
        protected static bool SeparatedByMinusMatch(string id, string q)
        {
            foreach (var part in id.Split('-'))
            {
                if (part.StartsWith(q, System.StringComparison.OrdinalIgnoreCase)) return true;
            }
            return false;
        }

        public IEnumerable<Resource> GetResources(IUnleash unleashClient)
        {
            var res = new List<Resource>();
            if (unleashClient.IsEnabled("pkg-push"))
                res.Add(
                    new Resource
                    {
                        id = "package",
                        type = "PackagePublish/2.0.0",
                        comment = "Package Publish service"
                    });
            if (unleashClient.IsEnabled("pkg-get"))
                res.Add(
                    new Resource
                    {
                        id = "package",
                        type = "PackageBaseAddress/3.0.0",
                        comment = "Package Base Address service"
                    });
            if (unleashClient.IsEnabled("pkg-autocomplete"))
                res.Add(
                    new Resource
                    {
                        id = "package",
                        type = "SearchAutocompleteService/3.5.0",
                        comment = "Auto complete service"
                    });
            if (unleashClient.IsEnabled("pkg-search"))
                res.Add(
                    new Resource
                    {
                        id = "package",
                        type = "SearchQueryService/3.5.0",
                        comment = "Search Query service"
                    });
            return res;

        }

    }
}