using System.Text;
using System.Text.Json;
using DiunaBI.Domain.Entities;
using DiunaBI.Infrastructure.Data;
using DiunaBI.Infrastructure.Plugins;
using Microsoft.Extensions.Logging;

namespace DiunaBI.Plugins.PedrolloPL.Importers;

public class PedrolloPLImportB3 : BaseDataImporter
{
    public override string ImporterType => "PedrolloPL.Import.B3";

    private readonly AppDbContext _db;
    private readonly ILogger<PedrolloPLImportB3> _logger;

    // Configuration properties
    private string? DataInboxName { get; set; }
    private string? DataInboxSource { get; set; }
    private string? StartDate { get; set; }
    private string? EndDate { get; set; }
    private string? ImportYear { get; set; }
    private bool IsEnabled { get; set; }

    // Cached deserialized data
    private List<List<object>>? _cachedRawData;
    private DataInbox? _cachedDataInbox;
    private Dictionary<string, string>? _regionCodeMap;

    public PedrolloPLImportB3(
        AppDbContext db,
        ILogger<PedrolloPLImportB3> logger)
    {
        _db = db;
        _logger = logger;
    }

    public override void Import(Layer importWorker)
    {
        try
        {
            _logger.LogInformation("{ImporterType}: Starting import for {ImportWorkerName} ({ImportWorkerId})",
                ImporterType, importWorker.Name, importWorker.Id);

            // Clear cache at start
            _cachedRawData = null;
            _cachedDataInbox = null;
            _regionCodeMap = null;

            LoadConfiguration(importWorker);
            ValidateConfiguration();

            if (!IsEnabled)
            {
                _logger.LogInformation("{ImporterType}: Import disabled for {ImportWorkerName}",
                    ImporterType, importWorker.Name);
                return;
            }

            // Find and deserialize DataInbox data
            FindAndDeserializeDataInbox();

            // Load region code mapping from dictionary layer
            LoadRegionCodeMapping();

            // Map data from DataInbox to Layer records
            var mappedRecords = MapDataToRecords();

            // Create new Import layer
            var importLayer = CreateImportLayer(importWorker);

            // Save records to database
            SaveRecordsToLayer(importLayer, mappedRecords);

            _logger.LogInformation("{ImporterType}: Successfully completed import for {ImportWorkerName} - Created {RecordCount} records",
                ImporterType, importWorker.Name, mappedRecords.Count);
        }
        catch (Exception e)
        {
            _logger.LogError(e, "{ImporterType}: Failed to import {ImportWorkerName} ({ImportWorkerId})",
                ImporterType, importWorker.Name, importWorker.Id);
            throw;
        }
        finally
        {
            // Clear cache after import
            _cachedRawData = null;
            _cachedDataInbox = null;
            _regionCodeMap = null;
        }
    }

    private void LoadConfiguration(Layer importWorker)
    {
        if (importWorker.Records == null) return;

        DataInboxName = GetRecordValue(importWorker.Records, "DataInboxName");
        DataInboxSource = GetRecordValue(importWorker.Records, "DataInboxSource");
        StartDate = GetRecordValue(importWorker.Records, "StartDate");
        EndDate = GetRecordValue(importWorker.Records, "EndDate");
        ImportYear = GetRecordValue(importWorker.Records, "ImportYear");
        IsEnabled = GetRecordValue(importWorker.Records, "IsEnabled") == "True";

        _logger.LogDebug(
            "{ImporterType}: Configuration loaded - DataInboxName: {DataInboxName}, Source: {Source}, Year: {Year}, Period: {StartDate} to {EndDate}, Enabled: {IsEnabled}",
            ImporterType, DataInboxName, DataInboxSource, ImportYear, StartDate, EndDate, IsEnabled);
    }

    private void ValidateConfiguration()
    {
        var errors = new List<string>();

        if (string.IsNullOrEmpty(DataInboxName)) errors.Add("DataInboxName is required");
        if (string.IsNullOrEmpty(DataInboxSource)) errors.Add("DataInboxSource is required");
        if (string.IsNullOrEmpty(StartDate)) errors.Add("StartDate is required");
        if (string.IsNullOrEmpty(EndDate)) errors.Add("EndDate is required");

        if (errors.Any())
        {
            throw new InvalidOperationException($"Configuration validation failed: {string.Join(", ", errors)}");
        }

        _logger.LogDebug("{ImporterType}: Configuration validated successfully", ImporterType);
    }

    private void FindAndDeserializeDataInbox()
    {
        _logger.LogDebug("{ImporterType}: Searching for DataInbox with Name='{DataInboxName}' and Source='{DataInboxSource}'",
            ImporterType, DataInboxName, DataInboxSource);

        // Find DataInbox by Name and Source, order by CreatedAt descending to get the latest
        var dataInbox = _db.DataInbox
            .Where(x => x.Name == DataInboxName && x.Source == DataInboxSource)
            .OrderByDescending(x => x.CreatedAt)
            .FirstOrDefault();

        if (dataInbox == null)
        {
            throw new InvalidOperationException(
                $"DataInbox not found with Name='{DataInboxName}' and Source='{DataInboxSource}'");
        }

        _logger.LogInformation("{ImporterType}: Found DataInbox - Id: {DataInboxId}, Name: {Name}, Source: {Source}, CreatedAt: {CreatedAt}",
            ImporterType, dataInbox.Id, dataInbox.Name, dataInbox.Source, dataInbox.CreatedAt);

        // Deserialize the data
        try
        {
            var data = Convert.FromBase64String(dataInbox.Data);
            var jsonString = Encoding.UTF8.GetString(data);

            _logger.LogDebug("{ImporterType}: Decoded {DataSize} bytes from base64",
                ImporterType, data.Length);

            // Deserialize as array of arrays: [["<nieznany>", 1183.15, ...], ["DOLNOŚLĄSKIE", ...]]
            var rawData = JsonSerializer.Deserialize<List<List<object>>>(jsonString);
            if (rawData == null || rawData.Count == 0)
            {
                throw new InvalidOperationException($"DataInbox.Data is empty for: {dataInbox.Name}");
            }

            _logger.LogInformation("{ImporterType}: Successfully deserialized {RowCount} rows from DataInbox",
                ImporterType, rawData.Count);

            // Log first few rows for debugging
            if (rawData.Count > 0)
            {
                var sampleSize = Math.Min(3, rawData.Count);
                _logger.LogDebug("{ImporterType}: Sample rows (first {SampleSize}):", ImporterType, sampleSize);
                for (int i = 0; i < sampleSize; i++)
                {
                    var row = rawData[i];
                    if (row.Count > 0)
                    {
                        var regionName = row[0]?.ToString() ?? "null";
                        var valueCount = row.Count - 1;
                        _logger.LogDebug("  [{Index}] Region: {Region}, Values: {ValueCount}",
                            i, regionName, valueCount);
                    }
                }
            }

            // Cache the deserialized data
            _cachedRawData = rawData;
            _cachedDataInbox = dataInbox;
        }
        catch (FormatException e)
        {
            _logger.LogError(e, "{ImporterType}: Invalid base64 data in DataInbox {DataInboxId}",
                ImporterType, dataInbox.Id);
            throw new InvalidOperationException($"Invalid base64 data in DataInbox: {dataInbox.Name}", e);
        }
        catch (JsonException e)
        {
            _logger.LogError(e, "{ImporterType}: Invalid JSON data in DataInbox {DataInboxId}",
                ImporterType, dataInbox.Id);
            throw new InvalidOperationException($"Invalid JSON data in DataInbox: {dataInbox.Name}", e);
        }
    }

    private void LoadRegionCodeMapping()
    {
        const string dictionaryLayerName = "L1-D-P2-CODES";

        _logger.LogDebug("{ImporterType}: Loading region code mapping from dictionary layer '{DictionaryLayerName}'",
            ImporterType, dictionaryLayerName);

        var dictionaryLayer = _db.Layers
            .Where(x => x.Name == dictionaryLayerName && x.Type == LayerType.Dictionary)
            .FirstOrDefault();

        if (dictionaryLayer == null)
        {
            throw new InvalidOperationException($"Dictionary layer '{dictionaryLayerName}' not found");
        }

        // Load records for the dictionary layer
        var records = _db.Records
            .Where(x => x.LayerId == dictionaryLayer.Id)
            .ToList();

        // Build mapping: Desc1 (region name) -> Code
        _regionCodeMap = records.ToDictionary(
            r => r.Desc1 ?? string.Empty,
            r => r.Code ?? string.Empty,
            StringComparer.OrdinalIgnoreCase);

        _logger.LogInformation("{ImporterType}: Loaded {MappingCount} region code mappings",
            ImporterType, _regionCodeMap.Count);
    }

    private List<Record> MapDataToRecords()
    {
        if (_cachedRawData == null)
        {
            throw new InvalidOperationException("Raw data not loaded. Call FindAndDeserializeDataInbox first.");
        }

        if (_regionCodeMap == null)
        {
            throw new InvalidOperationException("Region code mapping not loaded. Call LoadRegionCodeMapping first.");
        }

        var records = new List<Record>();
        var now = DateTime.UtcNow;

        _logger.LogDebug("{ImporterType}: Starting data mapping for {RowCount} rows",
            ImporterType, _cachedRawData.Count);

        foreach (var row in _cachedRawData)
        {
            if (row.Count < 13)
            {
                _logger.LogWarning("{ImporterType}: Skipping row with insufficient data - expected 13 elements, got {Count}",
                    ImporterType, row.Count);
                continue;
            }

            // First element is region name
            var regionName = row[0]?.ToString();
            if (string.IsNullOrEmpty(regionName))
            {
                _logger.LogWarning("{ImporterType}: Skipping row with empty region name", ImporterType);
                continue;
            }

            // Find region code from dictionary
            if (!_regionCodeMap.TryGetValue(regionName, out var regionCode))
            {
                _logger.LogWarning("{ImporterType}: Region code not found for '{RegionName}' - skipping",
                    ImporterType, regionName);
                continue;
            }

            // Create 12 records (one per month)
            for (int month = 1; month <= 12; month++)
            {
                var valueIndex = month; // row[1] = January, row[2] = February, etc.
                var valueObj = row[valueIndex];

                // Convert value to double
                double? value = null;
                if (valueObj != null)
                {
                    // Handle JsonElement if deserialized from JSON
                    if (valueObj is JsonElement jsonElement)
                    {
                        if (jsonElement.ValueKind == JsonValueKind.Number)
                        {
                            value = jsonElement.GetDouble();
                        }
                    }
                    else if (valueObj is double d)
                    {
                        value = d;
                    }
                    else if (double.TryParse(valueObj.ToString(), out var parsed))
                    {
                        value = parsed;
                    }
                }

                // Create code: {regionCode}{month:00}
                var code = $"{regionCode}{month:00}";

                var record = new Record
                {
                    Id = Guid.NewGuid(),
                    Code = code,
                    Value1 = value,
                    CreatedAt = now,
                    ModifiedAt = now
                };

                records.Add(record);
            }

            _logger.LogDebug("{ImporterType}: Mapped region '{RegionName}' (code: {RegionCode}) to 12 records",
                ImporterType, regionName, regionCode);
        }

        _logger.LogInformation("{ImporterType}: Successfully mapped {RecordCount} records from {RowCount} rows",
            ImporterType, records.Count, _cachedRawData.Count);

        return records;
    }

    private Layer CreateImportLayer(Layer importWorker)
    {
        var now = DateTime.UtcNow;

        var importLayer = new Layer
        {
            Id = Guid.NewGuid(),
            Number = _db.Layers.Count() + 1,
            ParentId = importWorker.Id,
            Type = LayerType.Import,
            IsCancelled = false,
            CreatedAt = now,
            ModifiedAt = now,
            CreatedById = Guid.Parse("f392209e-123e-4651-a5a4-0b1d6cf9ff9d"), // System user
            ModifiedById = Guid.Parse("f392209e-123e-4651-a5a4-0b1d6cf9ff9d")  // System user
        };

        importLayer.Name = $"L{importLayer.Number}-I-B3-{ImportYear}-{now:yyyyMMddHHmm}";

        _logger.LogDebug("{ImporterType}: Creating import layer '{LayerName}' (Number: {Number})",
            ImporterType, importLayer.Name, importLayer.Number);

        _db.Layers.Add(importLayer);
        _db.SaveChanges();

        _logger.LogInformation("{ImporterType}: Created import layer '{LayerName}' with Id: {LayerId}",
            ImporterType, importLayer.Name, importLayer.Id);

        return importLayer;
    }

    private void SaveRecordsToLayer(Layer importLayer, List<Record> records)
    {
        _logger.LogDebug("{ImporterType}: Saving {RecordCount} records to layer {LayerId}",
            ImporterType, records.Count, importLayer.Id);

        // Delete any existing records for this layer (shouldn't be any, but just in case)
        var toDelete = _db.Records.Where(x => x.LayerId == importLayer.Id).ToList();
        if (toDelete.Count > 0)
        {
            _logger.LogWarning("{ImporterType}: Found {ExistingCount} existing records for layer {LayerId}, removing them",
                ImporterType, toDelete.Count, importLayer.Id);
            _db.Records.RemoveRange(toDelete);
        }

        // Set all required properties for each record
        foreach (var record in records)
        {
            record.LayerId = importLayer.Id;
            record.CreatedById = Guid.Parse("f392209e-123e-4651-a5a4-0b1d6cf9ff9d"); // System user
            record.ModifiedById = Guid.Parse("f392209e-123e-4651-a5a4-0b1d6cf9ff9d"); // System user
            _db.Records.Add(record);
        }

        _db.SaveChanges();

        _logger.LogInformation("{ImporterType}: Successfully saved {RecordCount} records to layer '{LayerName}'",
            ImporterType, records.Count, importLayer.Name);
    }

    private string? GetRecordValue(ICollection<Record> records, string code)
    {
        return records.FirstOrDefault(x => x.Code == code)?.Desc1;
    }
}