using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using PowderCoating.Core.Interfaces;
using PowderCoating.Shared.Constants;
using System.Text;

namespace PowderCoating.Web.Controllers;

/// <summary>
/// Displays per-company SMS consent status for all customers. Intended for company admins to
/// verify compliance (who has opted in, who opted out, and when). SuperAdmins can also access
/// this via the normal admin impersonation path.
/// </summary>
[Authorize(Policy = AppConstants.Policies.CompanyAdminOnly)]
public class SmsConsentAuditController : Controller
{
    private readonly IUnitOfWork _unitOfWork;
    private readonly ILogger<SmsConsentAuditController> _logger;

    public SmsConsentAuditController(IUnitOfWork unitOfWork, ILogger<SmsConsentAuditController> logger)
    {
        _unitOfWork = unitOfWork;
        _logger = logger;
    }

    /// <summary>
    /// Shows the SMS consent audit report filtered by status and optional name/phone search.
    /// </summary>
    public async Task<IActionResult> Index(string? filter = "all", string? search = null)
    {
        try
        {
            var allCustomers = await _unitOfWork.Customers.GetAllAsync();

            if (!string.IsNullOrWhiteSpace(search))
            {
                var s = search.Trim().ToLower();
                allCustomers = allCustomers.Where(c =>
                    (c.ContactFirstName != null && c.ContactFirstName.ToLower().Contains(s)) ||
                    (c.ContactLastName  != null && c.ContactLastName.ToLower().Contains(s))  ||
                    (c.CompanyName      != null && c.CompanyName.ToLower().Contains(s))      ||
                    (c.MobilePhone      != null && c.MobilePhone.Contains(s))                ||
                    (c.Phone            != null && c.Phone.Contains(s)));
            }

            var allRows = allCustomers
                .OrderBy(c => c.CompanyName ?? c.ContactLastName ?? c.ContactFirstName)
                .Select(c => new SmsConsentRow
                {
                    CustomerId    = c.Id,
                    CustomerName  = GetDisplayName(c.IsCommercial, c.CompanyName, c.ContactFirstName, c.ContactLastName),
                    Phone         = c.Phone,
                    MobilePhone   = c.MobilePhone,
                    NotifyBySms   = c.NotifyBySms,
                    ConsentedAt   = c.SmsConsentedAt,
                    ConsentMethod = c.SmsConsentMethod,
                    OptedOutAt    = c.SmsOptedOutAt,
                    SmsStatus     = ResolveSmsStatus(c.NotifyBySms, c.SmsConsentedAt, c.SmsOptedOutAt)
                }).ToList();

            var optedIn  = allRows.Count(r => r.SmsStatus == "active");
            var optedOut = allRows.Count(r => r.SmsStatus == "opted-out");
            var never    = allRows.Count(r => r.SmsStatus == "never");

            var filtered = filter switch
            {
                "opted-in"  => allRows.Where(r => r.SmsStatus == "active").ToList(),
                "opted-out" => allRows.Where(r => r.SmsStatus == "opted-out").ToList(),
                "never"     => allRows.Where(r => r.SmsStatus == "never").ToList(),
                _           => allRows
            };

            var vm = new SmsConsentAuditViewModel
            {
                Rows                 = filtered,
                Filter               = filter ?? "all",
                Search               = search,
                TotalCount           = allRows.Count,
                OptedInCount         = optedIn,
                OptedOutCount        = optedOut,
                NeverSubscribedCount = never
            };

            return View(vm);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error loading SMS consent audit");
            return View(new SmsConsentAuditViewModel());
        }
    }

    /// <summary>
    /// Exports the SMS consent audit as a CSV file for compliance record-keeping.
    /// Includes all customers regardless of the current filter.
    /// </summary>
    public async Task<IActionResult> ExportCsv()
    {
        try
        {
            var customers = (await _unitOfWork.Customers.GetAllAsync())
                .OrderBy(c => c.CompanyName ?? c.ContactLastName ?? c.ContactFirstName)
                .ToList();

            var sb = new StringBuilder();
            sb.AppendLine("Customer Name,Phone,Mobile Phone,SMS Status,Consented At (UTC),Consent Method,Opted Out At (UTC)");

            foreach (var c in customers)
            {
                var name   = CsvEscape(GetDisplayName(c.IsCommercial, c.CompanyName, c.ContactFirstName, c.ContactLastName));
                var status = ResolveSmsStatus(c.NotifyBySms, c.SmsConsentedAt, c.SmsOptedOutAt) switch
                {
                    "active"    => "Opted In",
                    "opted-out" => "Opted Out",
                    _           => "Never Subscribed"
                };

                sb.AppendLine(string.Join(",",
                    name,
                    CsvEscape(c.Phone ?? ""),
                    CsvEscape(c.MobilePhone ?? ""),
                    status,
                    c.SmsConsentedAt.HasValue ? c.SmsConsentedAt.Value.ToString("yyyy-MM-dd HH:mm:ss") : "",
                    CsvEscape(c.SmsConsentMethod ?? ""),
                    c.SmsOptedOutAt.HasValue ? c.SmsOptedOutAt.Value.ToString("yyyy-MM-dd HH:mm:ss") : ""
                ));
            }

            var bytes = Encoding.UTF8.GetBytes(sb.ToString());
            return File(bytes, "text/csv", $"sms-consent-audit-{DateTime.UtcNow:yyyyMMdd}.csv");
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error exporting SMS consent audit");
            return RedirectToAction(nameof(Index));
        }
    }

    // ── Helpers ───────────────────────────────────────────────────────────────

    private static string ResolveSmsStatus(bool notifyBySms, DateTime? consentedAt, DateTime? optedOutAt)
    {
        if (notifyBySms) return "active";
        if (optedOutAt.HasValue || (consentedAt.HasValue && !notifyBySms)) return "opted-out";
        return "never";
    }

    private static string GetDisplayName(bool isCommercial, string? companyName, string? first, string? last)
    {
        if (!isCommercial)
        {
            var contact = $"{first} {last}".Trim();
            if (!string.IsNullOrEmpty(contact)) return contact;
        }
        if (!string.IsNullOrWhiteSpace(companyName)) return companyName;
        return $"{first} {last}".Trim() is { Length: > 0 } n ? n : "—";
    }

    private static string CsvEscape(string value)
    {
        if (value.Contains(',') || value.Contains('"') || value.Contains('\n'))
            return $"\"{value.Replace("\"", "\"\"")}\"";
        return value;
    }
}

// ── View models ───────────────────────────────────────────────────────────────

public class SmsConsentAuditViewModel
{
    public List<SmsConsentRow> Rows            { get; set; } = [];
    public string              Filter          { get; set; } = "all";
    public string?             Search          { get; set; }
    public int                 TotalCount      { get; set; }
    public int                 OptedInCount    { get; set; }
    public int                 OptedOutCount   { get; set; }
    public int                 NeverSubscribedCount { get; set; }
}

public class SmsConsentRow
{
    public int       CustomerId    { get; set; }
    public string    CustomerName  { get; set; } = "";
    public string?   Phone         { get; set; }
    public string?   MobilePhone   { get; set; }
    public bool      NotifyBySms   { get; set; }
    public string    SmsStatus     { get; set; } = "never"; // "active" | "opted-out" | "never"
    public DateTime? ConsentedAt   { get; set; }
    public string?   ConsentMethod { get; set; }
    public DateTime? OptedOutAt    { get; set; }

    public string StatusBadgeClass => SmsStatus switch
    {
        "active"    => "bg-success",
        "opted-out" => "bg-danger",
        _           => "bg-secondary"
    };

    public string StatusLabel => SmsStatus switch
    {
        "active"    => "Opted In",
        "opted-out" => "Opted Out",
        _           => "Never Subscribed"
    };
}