using Microsoft.Azure.Cosmos;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CDP
{
    internal class AuditDB
    {
        //https://learn.microsoft.com/en-us/azure/azure-functions/manage-connections?tabs=csharp#azure-cosmos-db-clients
        private static Lazy<CosmosClient> lazyClient = new Lazy<CosmosClient>(InitializeCosmosClient);
        private static CosmosClient cosmosClient => lazyClient.Value;
        private static string DatabaseName = "CDP";
        private static string FileAuditContainer = "FileAudits";
        private static string UserAuditContainer = "UserAudits";
        private static string GroupAuditContainer = "GroupAudits";
        private static string TenantAuditContainer = "TenantAudits";
        private static CosmosClient InitializeCosmosClient()
        {
            // Perform any initialization here
            var uri = "https://cdplite.documents.azure.com:443/";
            var authKey = "VPbg8RpzyI3XwhC2o0dIUtYFs33ghxORCqZeNAyg8vg4HWUBjM41BUxP0qLFXEvFh6ewQY1uKv52ACDbsEN1AQ==";

            return new CosmosClient(uri, authKey);
        }

        public static async Task UpdateAuditDocument(AuditDocument al, string containerName)
        {
            if (al.Records.Count == 0)
                return;

            List<AuditDocument> lal = await SplitAuditlog(al);

            Container container = cosmosClient.GetContainer(DatabaseName, containerName);

            foreach (AuditDocument ial in lal)
            {
                ItemResponse<AuditDocument> r = await container.UpsertItemAsync(ial, new PartitionKey(ial.id));
            }

            await UpdateMetadata(container, lal);
        }

        static async Task UpdateMetadata(Container container, List<AuditDocument> lal)
        {
            bool update = false;
            string pKey = GetMetaDocumentKey(lal[0].DocId);
            MetadataDocument md = null;
            try
            {
                ItemResponse<MetadataDocument> response =
                    await container.ReadItemAsync<MetadataDocument>(pKey, new PartitionKey(pKey));
                md = response.Resource;
            }
            catch (CosmosException ex) when (ex.StatusCode == System.Net.HttpStatusCode.NotFound)
            {
                md = new MetadataDocument()
                {
                    id = lal[0].DocId + "-meta",
                    PartitionKeys = new List<string>()
                };
            }
            catch (Exception e)
            {
                //                Helpers.LogIt(e.Message);
                return;
            }

            if (md == null)
            {
                //                Helpers.LogIt("Something ugly happened!");
                return;
            }

            foreach (AuditDocument log in lal)
            {
                if (md.PartitionKeys.Contains(log.id))
                    continue;
                md.PartitionKeys.Add(log.id);
                update = true;
            }

            if (update)
            {
                try
                {
                    ItemResponse<MetadataDocument> r = await container.UpsertItemAsync(md, new PartitionKey(pKey));
                }
                catch (Exception e)
                {
                    //                    Helpers.LogIt(e.Message);   
                    return;
                }
            }
        }

        public static async Task<AuditDocument> GetAuditDocument(string key, string ContainerName)
        {
            try
            {
                Container container = cosmosClient.GetContainer(DatabaseName, ContainerName);
                ItemResponse<AuditDocument> response = await container.ReadItemAsync<AuditDocument>(key, new PartitionKey(key));
                if (response == null)
                    return null;

                AuditDocument t = response.Resource;
                return t;
            }
            catch (Exception e)
            {
                return null;
            }
        }

        static async Task<MetadataDocument> GetMetadataDocument(string id, string ContainerName)
        {
            MetadataDocument md = null;
            string pKey = GetMetaDocumentKey(id);

            PartitionKey partitionKey = new PartitionKeyBuilder()
                    .Add(id)
                    .Build();
            Container container = cosmosClient.GetContainer(DatabaseName, ContainerName);
            try
            {
                ItemResponse<MetadataDocument> response =
                    await container.ReadItemAsync<MetadataDocument>(pKey, partitionKey);
                md = response.Resource;
            }
            catch (CosmosException ex) when (ex.StatusCode == System.Net.HttpStatusCode.NotFound)
            {
                md = new MetadataDocument()
                {
                    id = id,
                    PartitionKeys = new List<string>()
                };
            }
            catch (Exception e)
            {
                //                Helpers.LogIt(e.Message);
                return null;
            }

            if (md == null)
            {
                //                Helpers.LogIt("Something ugly happened!");
                return null;
            }
            return md;
        }

        public static async Task<List<AuditRecord>> GetAuditRecordsBetweenDates(string DocId, DateTime startDate, DateTime endDate, string ContainerName)
        {
            var results = new List<AuditRecord>();
            Container container = cosmosClient.GetContainer(DatabaseName, ContainerName);

            // Fetch the metadata document for the customer ID
            var metadataDocumentId = GetMetaDocumentKey(DocId);
            MetadataDocument metadataDocument = null;
            try
            {
                var metadataDocumentResponse =
                    await container.ReadItemAsync<MetadataDocument>(metadataDocumentId, new PartitionKey(metadataDocumentId));
                metadataDocument = metadataDocumentResponse.Resource;
            }
            catch (CosmosException ex) when (ex.StatusCode == System.Net.HttpStatusCode.NotFound)
            {
            }
            catch (Exception e)
            {
                //                Helpers.LogIt(e.Message);
            }

            if (metadataDocument == null)
                return results;

            // Determine the partition keys within the date range
            var partitionKeysInRange = metadataDocument.PartitionKeys
                .Where(pk => IsPartitionKeyInRange(pk, startDate, endDate))
                .ToList();

            // Fetch the audit records for each partition key within the date range
            foreach (var partitionKey in partitionKeysInRange)
            {

                ItemResponse<AuditDocument> response = await container.ReadItemAsync<AuditDocument>(partitionKey, new PartitionKey(partitionKey));
                if (response == null)
                    continue;

                AuditDocument t = response.Resource;
                results.AddRange(t.Records);
            }

            return results;
        }

        static private bool IsPartitionKeyInRange(string partitionKey, DateTime startDate, DateTime endDate)
        {
            var partitionKeyParts = partitionKey.Split('-');
            var length = partitionKeyParts.Length;

            var year = int.Parse(partitionKeyParts[length - 3]);
            var dayOfYear = int.Parse(partitionKeyParts[length - 2]);
            var partitionKeyDate = new DateTime(year, 1, 1).AddDays(dayOfYear - 1);

            return partitionKeyDate >= startDate && partitionKeyDate <= endDate;
        }

        public static async Task<bool> AppendRecord(string id, AuditRecord rec, string ContainerName)
        {
            try
            {
                var metadataDocument = await GetMetadataDocument(id, ContainerName);
                if (metadataDocument == null)
                    return false;

                string dayKey = metadataDocument.GetLatestKeyForDay(rec.EventTime);
                AuditDocument al = await GetAuditDocument(dayKey, ContainerName);
                if (al == null && ContainerName == FileAuditContainer)
                    al = new AuditDocument() { DocId = rec.FileId };
                else if (al == null && ContainerName == TenantAuditContainer)
                    al = new AuditDocument() { DocId = rec.AppKey };
                else if (al == null && ContainerName == UserAuditContainer)
                    al = new AuditDocument() { DocId = rec.UserId };
                else if (al == null && ContainerName == GroupAuditContainer)
                    al = new AuditDocument() { DocId = rec.GroupId };
                al.Records.Add(rec);
                await UpdateAuditDocument(al, ContainerName);
                return true;
            }
            catch (Exception e)
            {
                return false;
            }
        }

        public static async Task<bool> AppendRecordsList(string id, List<AuditRecord> rec, string ContainerName)
        {
            try
            {
                var metadataDocument = await GetMetadataDocument(id, ContainerName);
                if (metadataDocument == null || rec.Count <= 0)
                    return false;

                string dayKey = metadataDocument.GetLatestKeyForDay(rec[0].EventTime);
                AuditDocument al = await GetAuditDocument(dayKey, ContainerName);
                /*if (al == null && ContainerName == FileAuditContainer)
                    al = new AuditDocument() { DocId = rec.FileId };*/
                if (al == null && ContainerName == TenantAuditContainer)
                    al = new AuditDocument() { DocId = rec[0].AppKey };
                else if (al == null && ContainerName == UserAuditContainer)
                    al = new AuditDocument() { DocId = rec[0].UserId };

                rec.ForEach(record =>
                {
                    al.Records.Add(record);
                });
                await UpdateAuditDocument(al, ContainerName);
                return true;
            }
            catch (Exception e)
            {
                return false;
            }
        }




        public static async Task<GroupAuditDocument> GetGroupAuditDocument(string appKey, string groupId)
        {
            Container container = cosmosClient.GetContainer(DatabaseName, GroupAuditContainer);  // get the Group Container

            GroupAuditDocument ad = new GroupAuditDocument() { GroupId = groupId };
            try
            {
                // Store the unique identifier
                string id = groupId;

                PartitionKey partitionKey = new PartitionKeyBuilder()
                .Add(appKey)
                .Add(groupId)
                .Build();

                // Perform a point read
                ItemResponse<GroupAuditDocument> r = await container.ReadItemAsync<GroupAuditDocument>(id, partitionKey);
                return r;
            }

            catch (Exception e)
            {
                return null;
            }
        }
        public static async Task AddTenantAuditRecord(FileAuditRecord far)
        {
            TenantAuditRecord uar = new TenantAuditRecord()
            {
                Action = far.Action,
                AppKey = far.AppKey,
                EventTime = far.EventTime,
                FileId = far.FileId,
                GroupId = far.GroupId,
                Message = far.Message,
                UserId = far.UserId
            };

            // cosmosClient is init'd by the static on line 21
            Container container = cosmosClient.GetContainer(DatabaseName, TenantAuditContainer);
            // Build the full partition key path
            PartitionKey partitionKey = new PartitionKeyBuilder()
                .Add(uar.AppKey)
                .Build();

            TenantAuditDocument ad = await GetTenantAuditDocument(uar.AppKey);
            if (ad == null)
                ad = new TenantAuditDocument() { AppKey = uar.AppKey };

            ad.Records.Add(uar);
            try
            {
                ItemResponse<TenantAuditDocument> r = await container.UpsertItemAsync(ad, partitionKey);
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
            }
        }

        public static async Task<TenantAuditDocument> GetTenantAuditDocument(string appKey)
        {
            Container container = cosmosClient.GetContainer(DatabaseName, TenantAuditContainer);  // get the Group Container

            TenantAuditDocument ad = new TenantAuditDocument() { AppKey = appKey };
            try
            {
                // Store the unique identifier
                string id = appKey;

                PartitionKey partitionKey = new PartitionKeyBuilder()
                .Add(appKey)
                .Build();

                // Perform a point read
                ItemResponse<TenantAuditDocument> r = await container.ReadItemAsync<TenantAuditDocument>(id, partitionKey);
                return r;
            }

            catch (Exception e)
            {
                return null;
            }
        }

        static async Task<List<AuditDocument>> SplitAuditlog(AuditDocument al)
        {
            List<AuditDocument> lal = new List<AuditDocument>();
            var sortedRecords = al.Records.OrderBy(record => record.EventTime).ToList();

            var currentGroup = new List<AuditRecord>();
            var currentGroupSize = 0;

            int MaxDocumentSizeInBytes = 2 * 1024 * 1024; // 2MB

            int index = al.Index; // start for index passed in
            foreach (var record in sortedRecords)
            {
                var recordSize = record.CalculateRecordSize();

                if (currentGroupSize + recordSize > MaxDocumentSizeInBytes)
                {
                    AuditDocument i = new AuditDocument();
                    i.Index = index++;
                    i.Records = currentGroup;
                    lal.Add(i);

                    currentGroup = new List<AuditRecord>();
                    currentGroupSize = 0;
                }

                currentGroup.Add(record);
                currentGroupSize += recordSize;
            }

            if (currentGroup.Any())
            {
                AuditDocument i = new AuditDocument();
                i.DocId = al.DocId;
                i.Index = index++;
                i.Records = currentGroup;
                lal.Add(i);
            }

            return lal;
        }

        static string GetMetaDocumentKey(string id)
        {
            return $"{id}-meta";
        }
    }
}