using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using LaDOSE.Business.Interface;
using LaDOSE.Entity;
using Microsoft.Extensions.Logging;

namespace LaDOSE.Business.Provider.SheetsProvider
{
    /// <summary>
    /// Writes the export to the log instead of to Google, and reports success.
    ///
    /// This exists so the whole feature — button, ordering, cumulative prefixes, payload shape —
    /// can be exercised end to end before any Google account, key or sharing exists. Set
    /// GoogleSheets:Writer to "Logging" and read the API log. It is also the safe way to try a
    /// selection without touching the real spreadsheet.
    /// </summary>
    public class LoggingSheetsWriter : ISheetsWriter
    {
        private readonly ILogger<LoggingSheetsWriter> _logger;

        public LoggingSheetsWriter(ILogger<LoggingSheetsWriter> logger)
        {
            _logger = logger;
        }

        public string Name => "Logging";

        public bool IsConfigured => true;

        public Task<SheetExportResult> WriteTablesAsync(SheetExportRequest request, CancellationToken ct = default)
        {
            var tabs = request.Tabs ?? new List<SheetTable>();

            _logger.LogInformation(
                "Sheets export (Logging writer): spreadsheet {SpreadsheetId}, {TabCount} tabs",
                request.SpreadsheetId, tabs.Count);

            foreach (var tab in tabs)
            {
                var header = tab.Header ?? new List<string>();
                var rows = tab.Rows ?? new List<SheetRow>();

                _logger.LogInformation("  [{Name}] event {EventId}: {RowCount} rows x {ColumnCount} columns | {Header}",
                    tab.Name, tab.EventId, rows.Count, header.Count, string.Join(" | ", header));

                foreach (var row in rows)
                {
                    _logger.LogInformation("    {Player} | {Points} | {Total}",
                        row.Player, string.Join(" | ", row.Points ?? new List<int>()), row.Total);
                }

                foreach (var line in tab.Footer ?? new List<string>())
                {
                    _logger.LogInformation("    -- {Line}", line);
                }
            }

            return Task.FromResult(new SheetExportResult
            {
                SpreadsheetId = request.SpreadsheetId,
                SpreadsheetUrl = SheetUrl(request.SpreadsheetId),
                Writer = Name,
                Tabs = tabs.Select(tab => new SheetTabResult
                {
                    RequestedName = tab.Name,
                    Name = tab.Name,
                    Rows = (tab.Rows?.Count ?? 0) + 1,
                    Columns = tab.Header?.Count ?? 0,
                    // Nothing was inspected, so this is a claim rather than an observation.
                    Created = true
                }).ToList(),
                Warnings = new List<string>
                {
                    "Writer is 'Logging': nothing was written to Google. The payload is in the API log."
                }
            });
        }

        internal static string SheetUrl(string spreadsheetId)
        {
            return string.IsNullOrWhiteSpace(spreadsheetId)
                ? null
                : $"https://docs.google.com/spreadsheets/d/{spreadsheetId}/edit";
        }
    }
}