using System.Globalization;
using Google.Apis.Sheets.v4;
using Microsoft.Extensions.Logging;
using Microsoft.EntityFrameworkCore;
using DiunaBI.Core.Models;
using DiunaBI.Core.Database.Context;

namespace DiunaBI.Plugins.Morska.Importers;

public class MorskaStandardImporter : MorskaBaseImporter
{
    public override string ImporterType => "Morska.Import.Standard";

    private readonly AppDbContext _db;
    private readonly SpreadsheetsResource.ValuesResource _googleSheetValues;
    private readonly ILogger<MorskaStandardImporter> _logger;

    // Configuration properties
    private string? SheetId { get; set; }
    private string? SheetTabName { get; set; }
    private string? DataRange { get; set; }
    private string? ImportYear { get; set; }
    private string? ImportMonth { get; set; }
    private string? ImportName { get; set; }
    private DateTime? StartDate { get; set; }
    private DateTime? EndDate { get; set; }
    private bool IsEnabled { get; set; }

    private IList<IList<object>>? _cachedSheetData;
    private string? _cachedDataKey; 

    public MorskaStandardImporter(
        AppDbContext db,
        SpreadsheetsResource.ValuesResource googleSheetValues,
        ILogger<MorskaStandardImporter> logger)
    {
        _db = db;
        _googleSheetValues = googleSheetValues;
        _logger = logger;
    }

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

            // Clear cache before import
            _cachedSheetData = null;
            _cachedDataKey = null;

            // Load configuration from layer records
            LoadConfiguration(importWorker);

            // Check if import should be performed
            if (!ShouldPerformImport(importWorker))
            {
                _logger.LogInformation("{ImporterType}: Import not needed for {ImportWorkerName}",
                    ImporterType, importWorker.Name);
                return;
            }

            // Validate required configuration
            ValidateConfiguration();

            // Perform the actual import
            PerformImport(importWorker);

            _logger.LogInformation("{ImporterType}: Successfully completed import for {ImportWorkerName}",
                ImporterType, importWorker.Name);
        }
        catch (Exception e)
        {
            _logger.LogError(e, "{ImporterType}: Failed to import {ImportWorkerName} ({ImportWorkerId})",
                ImporterType, importWorker.Name, importWorker.Id);
            throw;
        }
        finally
        {
            // Clear cache after import
            _cachedSheetData = null;
            _cachedDataKey = null;
        }
    }

    private IList<IList<object>>? GetSheetData()
    {
        var currentDataKey = $"{SheetId}#{SheetTabName}#{DataRange}";
        
        if (_cachedSheetData != null && _cachedDataKey == currentDataKey)
        {
            _logger.LogDebug("{ImporterType}: Using cached sheet data for {DataKey}",
                ImporterType, currentDataKey);
            return _cachedSheetData;
        }

        try
        {
            _logger.LogDebug("{ImporterType}: Fetching data from Google Sheets API for {DataKey}",
                ImporterType, currentDataKey);

            var dataRangeResponse = _googleSheetValues.Get(SheetId!, $"{SheetTabName}!{DataRange}").Execute();
            _cachedSheetData = dataRangeResponse.Values;
            _cachedDataKey = currentDataKey;

            _logger.LogDebug("{ImporterType}: Cached {RowCount} rows from Google Sheet",
                ImporterType, _cachedSheetData?.Count ?? 0);

            return _cachedSheetData;
        }
        catch (Exception e)
        {
            _logger.LogError(e, "{ImporterType}: Error fetching data from Google Sheet {SheetId}",
                ImporterType, SheetId);
            throw;
        }
    }

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

        SheetId = GetRecordValue(importWorker.Records, "SheetId");
        SheetTabName = GetRecordValue(importWorker.Records, "SheetTabName");
        DataRange = GetRecordValue(importWorker.Records, "DataRange");
        ImportYear = GetRecordValue(importWorker.Records, "ImportYear");
        ImportMonth = GetRecordValue(importWorker.Records, "ImportMonth");
        ImportName = GetRecordValue(importWorker.Records, "ImportName");
        IsEnabled = GetRecordValue(importWorker.Records, "IsEnabled") == "True";

        var startDateStr = GetRecordValue(importWorker.Records, "StartDate");
        if (startDateStr != null && DateTime.TryParseExact(startDateStr, "yyyy.MM.dd", null, DateTimeStyles.None, out var startDate))
        {
            StartDate = startDate;
        }

        var endDateStr = GetRecordValue(importWorker.Records, "EndDate");
        if (endDateStr != null && DateTime.TryParseExact(endDateStr, "yyyy.MM.dd", null, DateTimeStyles.None, out var endDate))
        {
            EndDate = endDate;
        }

        _logger.LogDebug("{ImporterType}: Configuration loaded for {ImportWorkerName}",
            ImporterType, importWorker.Name);
    }

    private bool ShouldPerformImport(Layer importWorker)
    {
        if (!IsEnabled)
        {
            _logger.LogDebug("{ImporterType}: Import disabled for {ImportWorkerName}",
                ImporterType, importWorker.Name);
            return false;
        }

        // Check date range if configured
        if (StartDate.HasValue && EndDate.HasValue)
        {
            var now = DateTime.UtcNow.Date;
            if (now >= StartDate.Value.Date && now <= EndDate.Value.Date)
            {
                _logger.LogDebug("{ImporterType}: Within date range, import needed for {ImportWorkerName}",
                    ImporterType, importWorker.Name);
                return true;
            }

            // Outside date range - check if imported layer is up to date
            if (!IsImportedLayerUpToDate(importWorker))
            {
                _logger.LogDebug("{ImporterType}: Outside date range but layer is out of date, import needed for {ImportWorkerName}",
                    ImporterType, importWorker.Name);
                return true;
            }

            _logger.LogDebug("{ImporterType}: Outside date range and layer is up to date for {ImportWorkerName}",
                ImporterType, importWorker.Name);
            return false;
        }

        // No date constraints - always import
        return true;
    }

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

        if (string.IsNullOrEmpty(SheetId)) errors.Add("SheetId is required");
        if (string.IsNullOrEmpty(SheetTabName)) errors.Add("SheetTabName is required");
        if (string.IsNullOrEmpty(DataRange)) errors.Add("DataRange is required");
        if (string.IsNullOrEmpty(ImportYear)) errors.Add("ImportYear is required");
        if (string.IsNullOrEmpty(ImportMonth)) errors.Add("ImportMonth is required");
        if (string.IsNullOrEmpty(ImportName)) errors.Add("ImportName is required");

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

    private bool IsImportedLayerUpToDate(Layer importWorker)
    {
        var newestLayer = _db.Layers
            .Include(x => x.Records)
            .Where(x => x.ParentId == importWorker.Id)
            .OrderByDescending(x => x.CreatedAt)
            .AsNoTracking()
            .FirstOrDefault();

        if (newestLayer == null)
        {
            _logger.LogDebug("{ImporterType}: No child layers found for {ImportWorkerName}, treating as up to date",
                ImporterType, importWorker.Name);
            return true;
        }

        try
        {
            var data = GetSheetData();

            if (data == null || data.Count < 2)
            {
                _logger.LogWarning("{ImporterType}: No data found in sheet for {ImportWorkerName}", 
                    ImporterType, importWorker.Name);
                return true;
            }

            // Check if the number of columns matches
            if (data[0].Count != data[1].Count)
            {
                _logger.LogWarning("{ImporterType}: Column count mismatch in imported data for {ImportWorkerName}",
                    ImporterType, importWorker.Name);
                return false;
            }

            for (var i = 0; i < data[1].Count; i++)
            {
                if (string.IsNullOrEmpty(data[0][i]?.ToString()) ||
                    !double.TryParse(data[1][i]?.ToString(), CultureInfo.GetCultureInfo("pl-PL"), out var value))
                {
                    _logger.LogDebug("{ImporterType}: Skipping column {Index} - empty code or invalid value", 
                        ImporterType, i);
                    continue;
                }

                var existingRecord = newestLayer.Records?.FirstOrDefault(x => x.Code == data[0][i].ToString());
                if (existingRecord == null || existingRecord.Value1 != value)
                {
                    _logger.LogDebug("{ImporterType}: Imported data is newer or different for code {Code}", 
                        ImporterType, data[0][i]);
                    return false;
                }
            }
        }
        catch (Exception e)
        {
            _logger.LogError(e, "{ImporterType}: Error checking imported layer up-to-date status for {ImportWorkerName}",
                ImporterType, importWorker.Name);
            return false;
        }

        _logger.LogDebug("{ImporterType}: Imported layer is up to date for {ImportWorkerName}",
            ImporterType, importWorker.Name);
        return true;
    }

    private void PerformImport(Layer importWorker)
    {
        _logger.LogDebug("{ImporterType}: Importing from sheet {SheetId}, tab {SheetTabName}, range {DataRange}", 
            ImporterType, SheetId, SheetTabName, DataRange);

        var layer = new Layer
        {
            Id = Guid.NewGuid(),
            Number = _db.Layers.Count() + 1,
            ParentId = importWorker.Id,
            Type = LayerType.Import,
            CreatedById = Guid.Parse("F392209E-123E-4651-A5A4-0B1D6CF9FF9D"),
            ModifiedById = Guid.Parse("F392209E-123E-4651-A5A4-0B1D6CF9FF9D"),
            CreatedAt = DateTime.UtcNow,
            ModifiedAt = DateTime.UtcNow
        };
        layer.Name = $"L{layer.Number}-I-{ImportName}-{ImportYear}/{ImportMonth}-{DateTime.Now:yyyyMMddHHmm}";

        var newRecords = new List<Record>();

        try
        {
            var data = GetSheetData();

            _logger.LogDebug("{ImporterType}: Using data with {RowCount} rows from cache", 
                ImporterType, data?.Count ?? 0);

            if (data != null && data.Count >= 2)
            {
                for (var i = 0; i < data[1].Count; i++)
                {
                    if (string.IsNullOrEmpty(data[0][i]?.ToString()) ||
                        !double.TryParse(data[1][i]?.ToString(), CultureInfo.GetCultureInfo("pl-PL"), out var value))
                    {
                        _logger.LogDebug("{ImporterType}: Skipping column {Index} - empty code or invalid value", 
                            ImporterType, i);
                        continue;
                    }

                    var record = new Record
                    {
                        Id = Guid.NewGuid(),
                        Code = data[0][i].ToString(),
                        Value1 = value,
                        CreatedAt = DateTime.UtcNow,
                        ModifiedAt = DateTime.UtcNow
                    };
                    newRecords.Add(record);
                }
            }

            _db.Layers.Add(layer);
            SaveRecords(layer.Id, newRecords);
            _db.SaveChanges();

            _logger.LogInformation("{ImporterType}: Successfully imported {RecordCount} records for layer {LayerName} ({LayerId})", 
                ImporterType, newRecords.Count, layer.Name, layer.Id);
        }
        catch (Exception e)
        {
            _logger.LogError(e, "{ImporterType}: Error importing data from cached sheet data", ImporterType); 
            throw;
        }
    }

    private void SaveRecords(Guid layerId, ICollection<Record> records)
    {
        var toDelete = _db.Records.Where(x => x.LayerId == layerId).ToList();
        if (toDelete.Count > 0)
        {
            _db.Records.RemoveRange(toDelete);
        }

        foreach (var record in records)
        {
            record.CreatedById = Guid.Parse("F392209E-123E-4651-A5A4-0B1D6CF9FF9D");
            record.CreatedAt = DateTime.UtcNow;
            record.ModifiedById = Guid.Parse("F392209E-123E-4651-A5A4-0B1D6CF9FF9D");
            record.ModifiedAt = DateTime.UtcNow;
            record.LayerId = layerId;
            _db.Records.Add(record);
        }

        _logger.LogDebug("{ImporterType}: Saved {RecordCount} records for layer {LayerId}",
            ImporterType, records.Count, layerId);
    }

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