using Disco.Data.Repository;
using Disco.Models.Repository;
using Disco.Plugins.ServiceTracker.Models;
using System;
using System.Collections.Generic;
using System.Linq;

namespace Disco.Plugins.ServiceTracker.Services
{
    public class ServiceTrackerService
    {
        public const string PluginVersion = "1.2.0";

        private readonly DiscoDataContext _database;
        private readonly ServiceTrackerDataStore _dataStore;
        private readonly ServiceTrackerConfig _config;

        public ServiceTrackerService(DiscoDataContext database, ServiceTrackerDataStore dataStore)
        {
            _database = database;
            _dataStore = dataStore;
            _config = dataStore.LoadConfig();
        }

        public ServiceTrackerConfig Config { get { return _config; } }

        public DashboardViewModel BuildDashboard(string filterPriority = null, string filterLocation = null,
            string filterStatus = null, string filterTech = null, string sortBy = "due")
        {
            var tiles = new List<DashboardTile>();
            string sheetError = null;

            // --- Disco Jobs ---
            var openJobs = _database.Jobs
                .Include("Device").Include("Device.DeviceModel")
                .Include("User").Include("OpenedTechUser")
                .Include("JobType").Include("JobSubTypes")
                .Where(j => j.ClosedDate == null).ToList();

            var allTickets = _dataStore.LoadAllTickets();
            var ticketLookup = allTickets.ToDictionary(t => t.JobId, t => t);

            if (_config.AutoCreateTicketsForNewJobs)
            {
                foreach (var job in openJobs)
                {
                    if (!ticketLookup.ContainsKey(job.Id))
                    {
                        var newTicket = CreateDefaultTicket(job);
                        _dataStore.SaveTicket(newTicket);
                        ticketLookup[job.Id] = newTicket;
                    }
                }
            }

            foreach (var job in openJobs)
            {
                ServiceTicket ticket;
                ticketLookup.TryGetValue(job.Id, out ticket);
                tiles.Add(BuildDiscoTile(job, ticket));
            }

            // --- Google Sheet ---
            int sheetCount = 0;
            if (_config.GoogleSheet != null && _config.GoogleSheet.Enabled)
            {
                try
                {
                    var sheetSvc = new GoogleSheetService(_config.GoogleSheet, _dataStore.DataDirectory);
                    var sheetResult = sheetSvc.FetchTickets();
                    if (sheetResult.Error != null)
                    {
                        sheetError = sheetResult.Error;
                    }
                    else
                    {
                        if (sheetResult.Warning != null) sheetError = sheetResult.Warning;
                        var extTickets = _dataStore.LoadExternalTickets();
                        var extLookup = extTickets.ToDictionary(t => t.JobId, t => t);

                        foreach (var ext in sheetResult.Tickets)
                        {
                            ServiceTicket st;
                            if (!extLookup.TryGetValue(ext.InternalId, out st))
                            {
                                st = new ServiceTicket
                                {
                                    JobId = ext.InternalId, Source = "ntt",
                                    PriorityId = MapSheetPriority(ext.RawPriority),
                                    LocationId = _config.DefaultLocationId,
                                    AssignedTechId = ResolveSheetTech(ext.AssignedTo),
                                    Summary = ext.IssueDescription,
                                    CreatedDate = ext.Timestamp, LastModifiedDate = DateTime.Now
                                };
                                _dataStore.SaveExternalTicket(st);
                                extLookup[ext.InternalId] = st;
                            }
                            tiles.Add(BuildSheetTile(ext, st));
                            sheetCount++;
                        }
                    }
                }
                catch (Exception ex)
                {
                    sheetError = "Sheet error: " + ex.Message;
                }
            }

            // --- Ready for Return ---
            var readyForReturn = tiles.Where(t =>
            {
                var status = (t.StatusOverride ?? t.DiscoStatus ?? "").ToLower();
                return status.Contains("ready for return") || status.Contains("ready for pickup");
            }).ToList();

            // Remove from main tiles
            var mainTiles = tiles.Where(t => !readyForReturn.Contains(t)).ToList();

            // --- Filter ---
            if (!string.IsNullOrEmpty(filterPriority)) mainTiles = mainTiles.Where(t => t.PriorityId == filterPriority).ToList();
            if (!string.IsNullOrEmpty(filterLocation)) mainTiles = mainTiles.Where(t => t.LocationId == filterLocation).ToList();
            if (!string.IsNullOrEmpty(filterStatus)) mainTiles = mainTiles.Where(t => t.StatusOverride == filterStatus).ToList();
            if (!string.IsNullOrEmpty(filterTech)) mainTiles = mainTiles.Where(t => t.AssignedTechId == filterTech).ToList();

            // --- Sort ---
            switch (sortBy)
            {
                case "priority": mainTiles = mainTiles.OrderBy(t => t.PrioritySortOrder).ThenBy(t => t.SortDate).ToList(); break;
                case "age": mainTiles = mainTiles.OrderByDescending(t => t.AgeDays).ToList(); break;
                case "modified": mainTiles = mainTiles.OrderByDescending(t => t.LastModifiedDate).ToList(); break;
                case "sla": mainTiles = mainTiles.OrderBy(t => t.IsSlaBreached ? 0 : t.IsSlaWarning ? 1 : 2)
                    .ThenBy(t => t.SlaDeadline.HasValue ? t.SlaDeadline.Value : DateTime.MaxValue).ToList(); break;
                default: mainTiles = mainTiles.OrderBy(t => t.SortDate).ToList(); break;
            }

            var stats = BuildStats(mainTiles);
            stats.FromGoogleSheet = sheetCount;

            return new DashboardViewModel
            {
                Tiles = mainTiles, ReadyForReturn = readyForReturn,
                Stats = stats, Config = _config,
                CurrentFilter = filterPriority ?? filterLocation ?? filterStatus ?? "",
                SortBy = sortBy, GoogleSheetError = sheetError
            };
        }

        // --- Build Disco Tile ---
        private DashboardTile BuildDiscoTile(Job job, ServiceTicket ticket)
        {
            var now = DateTime.Now;
            var priorityId = (ticket != null ? ticket.PriorityId : null) ?? _config.DefaultPriorityId;
            var priority = _config.Priorities.FirstOrDefault(p => p.Id == priorityId) ?? _config.Priorities.FirstOrDefault();
            var locationId = (ticket != null ? ticket.LocationId : null) ?? _config.DefaultLocationId;
            var location = _config.Locations.FirstOrDefault(l => l.Id == locationId) ?? _config.Locations.FirstOrDefault();

            var slaDeadline = ticket != null ? ticket.SlaDeadline : (DateTime?)null;
            if (!slaDeadline.HasValue && priority != null && priority.SlaHours > 0)
                slaDeadline = job.OpenedDate.AddHours(priority.SlaHours);
            bool slaBreached = slaDeadline.HasValue && now > slaDeadline.Value;
            bool slaWarning = !slaBreached && slaDeadline.HasValue && priority != null && priority.SlaHours > 0
                              && now > slaDeadline.Value.AddHours(-priority.SlaHours * 0.25);

            int ageDays = (int)(now - job.OpenedDate).TotalDays;
            var eta = (ticket != null ? ticket.EstimatedCompletion : null) ?? job.ExpectedClosedDate;

            string discoStatus = "Open";
            if (job.WaitingForUserAction.HasValue) discoStatus = "Awaiting User Action";
            else if (job.DeviceHeld.HasValue && !job.DeviceReadyForReturn.HasValue) discoStatus = "Device Held";
            else if (job.DeviceReadyForReturn.HasValue && !job.DeviceReturnedDate.HasValue) discoStatus = "Ready for Return";

            string latestNote = null; int noteCount = 0;
            if (ticket != null && ticket.Notes != null && ticket.Notes.Count > 0)
            {
                noteCount = ticket.Notes.Count;
                var latest = ticket.Notes.OrderByDescending(n => n.Timestamp).First();
                latestNote = latest.Content;
                if (latestNote != null && latestNote.Length > 80) latestNote = latestNote.Substring(0, 77) + "...";
            }

            // Resolve tech display name
            var techId = ticket != null ? ticket.AssignedTechId : job.OpenedTechUserId;
            var techName = ResolveTechName(techId);

            return new DashboardTile
            {
                JobId = job.Id, Source = "disco", DisplayId = "DIC#" + job.Id,
                JobTypeDescription = job.JobType != null ? job.JobType.Description : job.JobTypeId,
                DeviceSerialNumber = job.DeviceSerialNumber ?? "\u2014",
                DeviceModelDescription = job.Device != null && job.Device.DeviceModel != null ? job.Device.DeviceModel.Description : null,
                DeviceComputerName = job.Device != null ? job.Device.DeviceDomainId : null,
                UserId = job.UserId,
                UserDisplayName = job.User != null ? job.User.DisplayName : job.UserId,
                OpenedByTechId = job.OpenedTechUserId,
                OpenedByTechName = job.OpenedTechUser != null ? job.OpenedTechUser.DisplayName : job.OpenedTechUserId,
                OpenedDate = job.OpenedDate, ExpectedClosedDate = job.ExpectedClosedDate, DiscoStatus = discoStatus,
                PriorityId = priorityId, PriorityName = priority != null ? priority.Name : "Unknown",
                PriorityColor = priority != null ? priority.Color : "#999", PrioritySortOrder = priority != null ? priority.SortOrder : 99,
                LocationId = locationId, LocationName = location != null ? location.Name : "Unknown",
                LocationIcon = location != null ? location.Icon : "", LocationColor = location != null ? location.Color : "#999",
                AssignedTechId = techId, AssignedTechName = techName,
                EstimatedCompletion = eta, SlaDeadline = slaDeadline,
                StatusOverride = ticket != null && ticket.StatusOverride != null ? ticket.StatusOverride : discoStatus,
                Summary = ticket != null ? ticket.Summary : null,
                NoteCount = noteCount, LatestNote = latestNote,
                LastModifiedDate = ticket != null ? ticket.LastModifiedDate : job.OpenedDate,
                IsSlaBreached = slaBreached, IsSlaWarning = slaWarning,
                AgeBadge = FormatAge(ageDays), AgeDays = ageDays, EtaDisplay = FormatEta(eta),
                SortDate = slaBreached && slaDeadline.HasValue ? slaDeadline.Value : eta.HasValue ? eta.Value : job.ExpectedClosedDate.HasValue ? job.ExpectedClosedDate.Value : job.OpenedDate
            };
        }

        // --- Build Sheet Tile ---
        private DashboardTile BuildSheetTile(ExternalTicket ext, ServiceTicket st)
        {
            var now = DateTime.Now;
            var priorityId = st != null ? st.PriorityId : MapSheetPriority(ext.RawPriority);
            var priority = _config.Priorities.FirstOrDefault(p => p.Id == priorityId) ?? _config.Priorities.FirstOrDefault();
            var locationId = st != null ? st.LocationId : _config.DefaultLocationId;
            var location = _config.Locations.FirstOrDefault(l => l.Id == locationId) ?? _config.Locations.FirstOrDefault();
            int ageDays = (int)(now - ext.Timestamp).TotalDays;
            var techId = st != null ? st.AssignedTechId : ResolveSheetTech(ext.AssignedTo);

            string latestNote = null; int noteCount = 0;
            if (st != null && st.Notes != null && st.Notes.Count > 0)
            {
                noteCount = st.Notes.Count;
                latestNote = st.Notes.OrderByDescending(n => n.Timestamp).First().Content;
                if (latestNote != null && latestNote.Length > 80) latestNote = latestNote.Substring(0, 77) + "...";
            }

            // Extract requester name from email
            var requesterName = ext.RequesterEmail ?? "Unknown";
            if (requesterName.Contains("@"))
                requesterName = requesterName.Split('@')[0].Replace(".", " ");

            return new DashboardTile
            {
                JobId = ext.InternalId, Source = "ntt", DisplayId = "NTT#" + ext.ExternalId.Replace("NTT", ""),
                JobTypeDescription = "Google Sheet",
                DeviceSerialNumber = ext.DeviceName ?? "\u2014",
                DeviceComputerName = ext.DeviceName,
                UserId = ext.RequesterEmail, UserDisplayName = requesterName,
                OpenedDate = ext.Timestamp, DiscoStatus = ext.RawStatus ?? "Open",
                PriorityId = priorityId, PriorityName = priority != null ? priority.Name : "Unknown",
                PriorityColor = priority != null ? priority.Color : "#999", PrioritySortOrder = priority != null ? priority.SortOrder : 99,
                LocationId = locationId, LocationName = location != null ? location.Name : "Unknown",
                LocationIcon = location != null ? location.Icon : "", LocationColor = location != null ? location.Color : "#999",
                AssignedTechId = techId, AssignedTechName = ResolveTechName(techId),
                StatusOverride = st != null && st.StatusOverride != null ? st.StatusOverride : (ext.RawStatus ?? "Open"),
                Summary = ext.IssueDescription, NoteCount = noteCount, LatestNote = latestNote,
                LastModifiedDate = st != null ? st.LastModifiedDate : ext.Timestamp,
                AgeBadge = FormatAge(ageDays), AgeDays = ageDays, EtaDisplay = FormatEta(st != null ? st.EstimatedCompletion : null),
                SortDate = st != null && st.EstimatedCompletion.HasValue ? st.EstimatedCompletion.Value : ext.Timestamp
            };
        }

        // --- Tech Resolution ---
        public string ResolveTechName(string techIdOrEmail)
        {
            if (string.IsNullOrEmpty(techIdOrEmail)) return null;
            foreach (var tech in _config.Technicians)
            {
                if (tech.Id == techIdOrEmail || tech.DisplayName == techIdOrEmail) return tech.DisplayName;
                if (!string.IsNullOrEmpty(tech.Email) && tech.Email.Equals(techIdOrEmail, StringComparison.OrdinalIgnoreCase)) return tech.DisplayName;
                if (tech.DiscoUserIds != null)
                {
                    foreach (var did in tech.DiscoUserIds)
                    {
                        if (did.Equals(techIdOrEmail, StringComparison.OrdinalIgnoreCase)) return tech.DisplayName;
                    }
                }
            }
            // Fallback to Disco user lookup
            try
            {
                var user = _database.Users.FirstOrDefault(u => u.UserId == techIdOrEmail);
                if (user != null) return user.DisplayName;
            }
            catch { }
            return techIdOrEmail;
        }

        private string ResolveSheetTech(string assignedTo)
        {
            if (string.IsNullOrEmpty(assignedTo)) return null;
            foreach (var tech in _config.Technicians)
            {
                if (!string.IsNullOrEmpty(tech.Email) && tech.Email.Equals(assignedTo, StringComparison.OrdinalIgnoreCase)) return tech.Id;
                if (tech.DisplayName.Equals(assignedTo, StringComparison.OrdinalIgnoreCase)) return tech.Id;
            }
            return assignedTo;
        }

        private string MapSheetPriority(string raw)
        {
            if (string.IsNullOrEmpty(raw)) return _config.DefaultPriorityId;
            raw = raw.ToLower().Trim();
            foreach (var p in _config.Priorities)
            {
                if (p.Name.ToLower() == raw || p.Id == raw) return p.Id;
            }
            if (raw.Contains("critical") || raw.Contains("urgent")) return "critical";
            if (raw.Contains("high")) return "high";
            if (raw.Contains("low")) return "low";
            return _config.DefaultPriorityId;
        }

        // --- CRUD ---
        public void UpdateTicket(int jobId, string source, string priorityId, string locationId,
            string assignedTechId, DateTime? eta, string status, string summary, string modifiedBy)
        {
            ServiceTicket ticket;
            if (source == "ntt")
                ticket = _dataStore.GetExternalTicket(jobId);
            else
                ticket = _dataStore.GetTicket(jobId);

            if (ticket == null) ticket = new ServiceTicket { JobId = jobId, Source = source ?? "disco" };
            if (ticket.ChangeLog == null) ticket.ChangeLog = new List<ChangeEntry>();

            Action<string, string, string> trackChange = (field, oldVal, newVal) =>
            {
                if (oldVal != newVal) ticket.ChangeLog.Add(new ChangeEntry { UserId = modifiedBy, Field = field, OldValue = oldVal, NewValue = newVal });
            };

            if (priorityId != null && priorityId != ticket.PriorityId) { trackChange("Priority", ticket.PriorityId, priorityId); ticket.PriorityId = priorityId; }
            if (locationId != null && locationId != ticket.LocationId) { trackChange("Location", ticket.LocationId, locationId); ticket.LocationId = locationId; }
            if (assignedTechId != null && assignedTechId != ticket.AssignedTechId) { trackChange("Assigned Tech", ticket.AssignedTechId, assignedTechId); ticket.AssignedTechId = assignedTechId; }
            if (status != null && status != ticket.StatusOverride) { trackChange("Status", ticket.StatusOverride ?? "(default)", string.IsNullOrEmpty(status) ? "(default)" : status); ticket.StatusOverride = status; }
            if (summary != null && summary != ticket.Summary) { trackChange("Summary", null, "(updated)"); ticket.Summary = summary; }
            if (eta.HasValue)
            {
                var oldEta = ticket.EstimatedCompletion.HasValue ? ticket.EstimatedCompletion.Value.ToString("dd MMM yyyy") : "none";
                var newEta = eta.Value.ToString("dd MMM yyyy");
                if (oldEta != newEta) { trackChange("ETA", oldEta, newEta); ticket.EstimatedCompletion = eta; }
            }

            ticket.LastModifiedBy = modifiedBy;
            if (priorityId != null)
            {
                var p = _config.Priorities.FirstOrDefault(x => x.Id == priorityId);
                ticket.SlaDeadline = (p != null && p.SlaHours > 0) ? ticket.CreatedDate.AddHours(p.SlaHours) : (DateTime?)null;
            }

            if (source == "ntt") _dataStore.SaveExternalTicket(ticket);
            else _dataStore.SaveTicket(ticket);
        }

        public void AddNote(int jobId, string source, string authorId, string authorName, string content, string noteType)
        {
            var note = new TicketNote { AuthorId = authorId, AuthorName = authorName, Content = content, NoteType = noteType ?? "general" };

            if (source == "ntt")
                _dataStore.AddExternalNote(jobId, note);
            else
            {
                _dataStore.AddNote(jobId, note);
                // Write back to Disco
                WriteNoteToDisco(jobId, authorId, content);
            }
        }

        private void WriteNoteToDisco(int jobId, string techUserId, string content)
        {
            try
            {
                var job = _database.Jobs.FirstOrDefault(j => j.Id == jobId);
                if (job == null) return;
                var log = new JobLog
                {
                    JobId = jobId,
                    TechUserId = techUserId,
                    Timestamp = DateTime.Now,
                    Comments = "[Service Tracker] " + content
                };
                _database.JobLogs.Add(log);
                _database.SaveChanges();
            }
            catch { }
        }

        public void MarkCollected(int jobId, string source, string userId)
        {
            UpdateTicket(jobId, source, null, null, null, null, "Resolved", null, userId);
        }

        public ServiceTicket GetTicketDetail(int jobId, string source)
        {
            if (source == "ntt") return _dataStore.GetExternalTicket(jobId);
            return _dataStore.GetTicket(jobId);
        }

        // --- Helpers ---
        private string FormatAge(int ageDays)
        {
            if (ageDays == 0) return "Today";
            if (ageDays == 1) return "1 day";
            if (ageDays < 7) return ageDays + " days";
            if (ageDays < 30) return (ageDays / 7) + " wk" + (ageDays / 7 > 1 ? "s" : "");
            return (ageDays / 30) + " mo" + (ageDays / 30 > 1 ? "s" : "");
        }

        private string FormatEta(DateTime? eta)
        {
            if (!eta.HasValue) return "\u2014";
            var days = (int)(eta.Value - DateTime.Now).TotalDays;
            if (days < 0) return Math.Abs(days) + "d overdue";
            if (days == 0) return "Today";
            if (days == 1) return "Tomorrow";
            return eta.Value.ToString("dd MMM");
        }

        private DashboardStats BuildStats(List<DashboardTile> tiles)
        {
            var s = new DashboardStats
            {
                TotalOpen = tiles.Count, SlaBreached = tiles.Count(t => t.IsSlaBreached),
                SlaWarning = tiles.Count(t => t.IsSlaWarning),
                AvgAgeDays = tiles.Count > 0 ? Math.Round(tiles.Average(t => (double)t.AgeDays), 1) : 0,
                OldestJobDays = tiles.Count > 0 ? tiles.Max(t => t.AgeDays) : 0
            };
            foreach (var p in _config.Priorities) s.ByPriority[p.Id] = tiles.Count(t => t.PriorityId == p.Id);
            s.Critical = tiles.Count(t => t.PriorityId == "critical"); s.High = tiles.Count(t => t.PriorityId == "high");
            s.Medium = tiles.Count(t => t.PriorityId == "medium"); s.Low = tiles.Count(t => t.PriorityId == "low");
            s.Scheduled = tiles.Count(t => t.PriorityId == "scheduled");
            foreach (var l in _config.Locations) s.ByLocation[l.Id] = tiles.Count(t => t.LocationId == l.Id);
            s.InItOffice = tiles.Count(t => t.LocationId == "it-office"); s.WithUser = tiles.Count(t => t.LocationId == "with-user");
            s.AtRepairer = tiles.Count(t => t.LocationId == "at-repairer");
            foreach (var tile in tiles)
            {
                var st = tile.StatusOverride ?? "Open";
                if (!s.ByStatus.ContainsKey(st)) s.ByStatus[st] = 0; s.ByStatus[st]++;
            }
            foreach (var tile in tiles.Where(t => !string.IsNullOrEmpty(t.AssignedTechId)))
            {
                var tn = tile.AssignedTechName ?? tile.AssignedTechId;
                if (!s.ByTech.ContainsKey(tn)) s.ByTech[tn] = 0; s.ByTech[tn]++;
            }
            return s;
        }

        private ServiceTicket CreateDefaultTicket(Job job)
        {
            var priority = _config.Priorities.FirstOrDefault(p => p.Id == _config.DefaultPriorityId);
            DateTime? sla = (priority != null && priority.SlaHours > 0) ? job.OpenedDate.AddHours(priority.SlaHours) : (DateTime?)null;
            string locId = _config.DefaultLocationId;
            if (job.DeviceHeld.HasValue && !string.IsNullOrEmpty(job.DeviceHeldLocation))
            {
                var ml = _config.Locations.FirstOrDefault(l => l.Name.Equals(job.DeviceHeldLocation, StringComparison.OrdinalIgnoreCase));
                if (ml != null) locId = ml.Id;
            }
            var techId = ResolveDiscoTechToId(job.OpenedTechUserId);
            return new ServiceTicket
            {
                JobId = job.Id, Source = "disco", PriorityId = _config.DefaultPriorityId, LocationId = locId,
                AssignedTechId = techId, EstimatedCompletion = job.ExpectedClosedDate,
                SlaDeadline = sla, CreatedDate = DateTime.Now, LastModifiedDate = DateTime.Now
            };
        }

        private string ResolveDiscoTechToId(string discoUserId)
        {
            if (string.IsNullOrEmpty(discoUserId)) return null;
            foreach (var tech in _config.Technicians)
            {
                if (tech.DiscoUserIds != null)
                {
                    foreach (var did in tech.DiscoUserIds)
                    {
                        if (did.Equals(discoUserId, StringComparison.OrdinalIgnoreCase)) return tech.Id;
                    }
                }
            }
            return discoUserId;
        }
    }
}