using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.RateLimiting;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using PowderCoating.Application.Interfaces;
using PowderCoating.Core.Enums;
using PowderCoating.Core.Interfaces;
using PowderCoating.Infrastructure.Data;
using PowderCoating.Shared.Constants;
using Stripe;
using AccountSubTypeEnum = PowderCoating.Core.Enums.AccountSubType;

namespace PowderCoating.Web.Controllers;

/// <summary>
/// Public (unauthenticated) controller for customer-facing invoice payment pages.
/// All actions here are accessible without login — security is enforced via signed tokens.
/// </summary>
[AllowAnonymous]
[EnableRateLimiting(AppConstants.RateLimitPolicies.Public)]
public class PaymentController : Controller
{
    private readonly ApplicationDbContext _context;
    private readonly IStripeConnectService _stripeConnect;
    private readonly INotificationService _notificationService;
    private readonly IInAppNotificationService _inApp;
    private readonly IConfiguration _configuration;
    private readonly ILogger<PaymentController> _logger;
    private readonly IAccountBalanceService _accountBalanceService;

    public PaymentController(
        ApplicationDbContext context,
        IStripeConnectService stripeConnect,
        INotificationService notificationService,
        IInAppNotificationService inApp,
        IConfiguration configuration,
        ILogger<PaymentController> logger,
        IAccountBalanceService accountBalanceService)
    {
        _context = context;
        _stripeConnect = stripeConnect;
        _notificationService = notificationService;
        _inApp = inApp;
        _configuration = configuration;
        _logger = logger;
        _accountBalanceService = accountBalanceService;
    }

    // ─── GET /pay/{token} ────────────────────────────────────────────────────

    /// <summary>
    /// Renders the customer-facing invoice payment page. Resolves the invoice from the GUID token
    /// embedded in the email link, validates that the token is not expired and the invoice is still
    /// unpaid, then builds the view model with surcharge details and the Stripe publishable key.
    /// Uses <see cref="ResolveInvoiceFromTokenAsync"/> so validation logic is shared with
    /// <see cref="CreateIntent"/>.
    /// </summary>
    [HttpGet("/pay/{token}")]
    public async Task<IActionResult> Index(string token)
    {
        var (invoice, company, error) = await ResolveInvoiceFromTokenAsync(token);
        if (error != null) return View("PaymentError", error);

        var customer = await _context.Customers.AsNoTracking()
            .FirstOrDefaultAsync(c => c.Id == invoice!.CustomerId);

        var surcharge = CalculateSurcharge(invoice!.BalanceDue, company!);

        var vm = new PaymentPageViewModel
        {
            InvoiceNumber    = invoice!.InvoiceNumber,
            InvoiceId        = invoice.Id,
            Token            = token,
            CustomerName     = customer != null
                ? $"{customer.ContactFirstName} {customer.ContactLastName}".Trim()
                : "Valued Customer",
            CustomerEmail    = customer?.Email ?? string.Empty,
            CompanyName      = company!.CompanyName,
            BalanceDue       = invoice.BalanceDue,
            InvoiceTotal     = invoice.Total,
            AmountPaid       = invoice.AmountPaid,   // already includes online payments
            SurchargeType    = company.OnlinePaymentSurchargeType,
            SurchargeValue   = company.OnlinePaymentSurchargeValue,
            SurchargeAmount  = surcharge,
            TotalWithSurcharge = invoice.BalanceDue + surcharge,
            ExpiresAt        = invoice.PaymentLinkExpiresAt!.Value,
            IsFullyPaid      = invoice.BalanceDue <= 0,
            StripePublishableKey = _configuration["Stripe:Connect:PublishableKey"]!,
            StripeAccountId  = company.StripeAccountId!
        };

        return View(vm);
    }

    // ─── GET /pay/{token}/success ────────────────────────────────────────────
    // Stripe redirects here after the customer completes payment in the browser.

    /// <summary>
    /// Renders the post-payment success page after Stripe redirects the customer back to the site.
    /// The token is kept in the URL only to maintain URL consistency with the payment page — it is
    /// not validated here because the payment result is authoritative via the webhook.
    /// </summary>
    [HttpGet("/pay/{token}/success")]
    public IActionResult Success(string token) => View();

    // ─── POST /pay/{token}/intent ─────────────────────────────────────────────
    // Creates a PaymentIntent for the amount the customer chose to pay.

    /// <summary>
    /// Creates a Stripe PaymentIntent for a partial or full invoice payment. Re-validates the token
    /// on every call so a shared or replayed link cannot be used after the invoice is fully paid or
    /// expired. The surcharge (flat or percentage, configured per company) is added on top of the
    /// requested amount and passed through to Stripe metadata so the webhook can strip it out when
    /// recording <c>netPayment</c> against the invoice balance.
    /// Sets <c>OnlinePaymentStatus = Pending</c> and saves the PaymentIntent ID to support idempotency
    /// checks in <see cref="HandlePaymentSucceededAsync"/>.
    /// </summary>
    [HttpPost("/pay/{token}/intent")]
    public async Task<IActionResult> CreateIntent(string token, [FromBody] CreateIntentRequest request)
    {
        var (invoice, company, error) = await ResolveInvoiceFromTokenAsync(token);
        if (error != null) return BadRequest(new { error });

        // Validate amount — must be > 0 and <= balance due
        if (request.Amount <= 0 || request.Amount > invoice!.BalanceDue)
            return BadRequest(new { error = "Invalid payment amount." });

        var surcharge = CalculateSurcharge(request.Amount, company!);
        var customer = await _context.Customers.AsNoTracking()
            .FirstOrDefaultAsync(c => c.Id == invoice.CustomerId);

        var (success, clientSecret, paymentIntentId, stripeError) =
            await _stripeConnect.CreatePaymentIntentAsync(
                connectedAccountId: company!.StripeAccountId!,
                invoiceTotal: request.Amount,
                surchargeAmount: surcharge,
                currency: "usd",
                customerEmail: customer?.Email ?? string.Empty,
                invoiceNumber: invoice.InvoiceNumber,
                invoiceId: invoice.Id);

        if (!success)
            return BadRequest(new { error = stripeError });

        // Store the latest PaymentIntent ID on the invoice
        invoice.StripePaymentIntentId = paymentIntentId;
        if (invoice.OnlinePaymentStatus == OnlinePaymentStatus.NotApplicable)
            invoice.OnlinePaymentStatus = OnlinePaymentStatus.Pending;
        _context.Update(invoice);
        await _context.SaveChangesAsync();

        return Ok(new { clientSecret, surchargeAmount = surcharge });
    }

    // ─── GET /invoice/{token} ────────────────────────────────────────────────

    /// <summary>
    /// Customer-facing read-only invoice view page. Resolved via PublicViewToken (permanent, no expiry).
    /// Shows full line items, totals, and company branding. If a valid PaymentLinkToken exists, renders
    /// a "Pay Now" button linking to /pay/{paymentLinkToken}. This is the link sent in SMS messages
    /// since SMS cannot attach a PDF.
    /// </summary>
    [HttpGet("/invoice/{token}")]
    public async Task<IActionResult> InvoiceView(string token)
    {
        try
        {
            var invoice = await _context.Invoices
                .AsNoTracking()
                .Include(i => i.InvoiceItems)
                .Include(i => i.Customer)
                .Include(i => i.Job)
                .IgnoreQueryFilters()
                .FirstOrDefaultAsync(i => i.PublicViewToken == token && !i.IsDeleted);

            if (invoice == null)
                return View("PaymentError", "This invoice link is invalid or has been removed.");

            var company = await _context.Companies.AsNoTracking()
                .IgnoreQueryFilters()
                .FirstOrDefaultAsync(c => c.Id == invoice.CompanyId && !c.IsDeleted);

            if (company == null)
                return View("PaymentError", "Unable to load invoice details.");

            var paymentUrl = (!string.IsNullOrEmpty(invoice.PaymentLinkToken)
                && invoice.PaymentLinkExpiresAt > DateTime.UtcNow
                && invoice.BalanceDue > 0)
                ? $"{Request.Scheme}://{Request.Host}/pay/{invoice.PaymentLinkToken}"
                : null;

            var vm = new InvoiceViewViewModel
            {
                InvoiceNumber  = invoice.InvoiceNumber,
                InvoiceDate    = invoice.InvoiceDate,
                DueDate        = invoice.DueDate,
                CustomerName   = invoice.Customer != null
                    ? $"{invoice.Customer.ContactFirstName} {invoice.Customer.ContactLastName}".Trim()
                    : "Valued Customer",
                CompanyName    = company.CompanyName,
                CompanyPhone   = company.Phone,
                CompanyAddress = string.Join(", ", new[] { company.Address, company.City, company.State, company.ZipCode }
                    .Where(s => !string.IsNullOrWhiteSpace(s))),
                LogoFilePath   = company.LogoFilePath,
                SubTotal       = invoice.SubTotal,
                TaxPercent     = invoice.TaxPercent,
                TaxAmount      = invoice.TaxAmount,
                DiscountAmount = invoice.DiscountAmount,
                Total          = invoice.Total,
                AmountPaid     = invoice.AmountPaid,
                BalanceDue     = invoice.BalanceDue,
                Status         = invoice.Status,
                Notes          = invoice.Notes,
                Terms          = invoice.Terms,
                JobNumber      = invoice.Job?.JobNumber,
                PaymentUrl     = paymentUrl,
                LineItems      = invoice.InvoiceItems.Select(i => new InvoiceViewLineItem
                {
                    Description = i.Description,
                    Quantity    = i.Quantity,
                    UnitPrice   = i.UnitPrice,
                    TotalPrice  = i.TotalPrice
                }).ToList()
            };

            return View(vm);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "InvoiceView failed for token {Token}", token);
            return View("PaymentError", "An error occurred loading this invoice.");
        }
    }

    // ─── GET /pay/deposit/{token} ────────────────────────────────────────────

    /// <summary>
    /// Renders the customer-facing deposit payment page for an approved quote. The deposit amount is
    /// calculated as <c>Quote.Total × (DepositPercent / 100)</c>; the percentage is set by the company
    /// when generating the quote link. Uses <see cref="ResolveDepositQuoteFromTokenAsync"/> to validate
    /// the token and confirm the deposit has not already been paid.
    /// </summary>
    [HttpGet("/pay/deposit/{token}")]
    public async Task<IActionResult> Deposit(string token)
    {
        var (quote, company, error) = await ResolveDepositQuoteFromTokenAsync(token);
        if (error != null) return View("PaymentError", error);

        var customer = quote!.Customer
            ?? await _context.Customers.AsNoTracking().FirstOrDefaultAsync(c => c.Id == quote.CustomerId);

        var depositAmount = Math.Round(quote.Total * (quote.DepositPercent / 100m), 2);
        var surcharge = CalculateSurcharge(depositAmount, company!);

        var vm = new DepositPaymentPageViewModel
        {
            QuoteNumber          = quote.QuoteNumber,
            QuoteId              = quote.Id,
            Token                = token,
            CustomerName         = customer != null
                ? $"{customer.ContactFirstName} {customer.ContactLastName}".Trim()
                : quote.ProspectContactName ?? "Valued Customer",
            CustomerEmail        = customer?.Email ?? quote.ProspectEmail ?? string.Empty,
            CompanyName          = company!.CompanyName,
            DepositAmount        = depositAmount,
            QuoteTotal           = quote.Total,
            DepositPercent       = quote.DepositPercent,
            SurchargeType        = company.OnlinePaymentSurchargeType,
            SurchargeValue       = company.OnlinePaymentSurchargeValue,
            SurchargeAmount      = surcharge,
            TotalWithSurcharge   = depositAmount + surcharge,
            ExpiresAt            = quote.DepositPaymentLinkExpiresAt!.Value,
            StripePublishableKey = _configuration["Stripe:Connect:PublishableKey"]!,
            StripeAccountId      = company.StripeAccountId!
        };

        return View(vm);
    }

    // ─── POST /pay/deposit/{token}/intent ────────────────────────────────────

    /// <summary>
    /// Creates a Stripe PaymentIntent for a quote deposit payment. The deposit amount is always the
    /// full computed deposit (not a partial amount chosen by the customer), so the <c>request.Amount</c>
    /// parameter from the client is intentionally ignored in favour of the server-calculated value.
    /// This prevents a malicious actor from sending an artificially low amount. The PaymentIntent ID
    /// is stored on the quote immediately so <see cref="HandleDepositPaymentSucceededAsync"/> can
    /// perform idempotency checks.
    /// </summary>
    [HttpPost("/pay/deposit/{token}/intent")]
    public async Task<IActionResult> CreateDepositIntent(string token, [FromBody] CreateIntentRequest request)
    {
        var (quote, company, error) = await ResolveDepositQuoteFromTokenAsync(token);
        if (error != null) return BadRequest(new { error });

        var depositAmount = Math.Round(quote!.Total * (quote.DepositPercent / 100m), 2);
        var surcharge = CalculateSurcharge(depositAmount, company!);
        var customerEmail = quote.Customer?.Email ?? quote.ProspectEmail ?? string.Empty;

        var (success, clientSecret, paymentIntentId, stripeError) =
            await _stripeConnect.CreateDepositPaymentIntentAsync(
                connectedAccountId: company!.StripeAccountId!,
                depositAmount: depositAmount,
                surchargeAmount: surcharge,
                currency: "usd",
                customerEmail: customerEmail,
                quoteNumber: quote.QuoteNumber,
                quoteId: quote.Id);

        if (!success)
            return BadRequest(new { error = stripeError });

        quote.DepositPaymentIntentId = paymentIntentId;
        _context.Update(quote);
        await _context.SaveChangesAsync();

        return Ok(new { clientSecret, surchargeAmount = surcharge });
    }

    // ─── GET /pay/deposit/{token}/success ────────────────────────────────────

    /// <summary>
    /// Renders the post-deposit success page shown to the customer after Stripe redirects back.
    /// Actual deposit recording happens in <see cref="HandleDepositPaymentSucceededAsync"/> via webhook,
    /// not here — this is purely a user-facing confirmation screen.
    /// </summary>
    [HttpGet("/pay/deposit/{token}/success")]
    public IActionResult DepositSuccess(string token) => View();

    // ─── POST /stripe/connect-webhook ────────────────────────────────────────
    // Stripe calls this when a payment on a connected account succeeds.

    /// <summary>
    /// Receives Stripe Connect account-level webhook events for payments made on connected
    /// (tenant) Stripe accounts. This is distinct from the platform-level webhook handled by
    /// <c>StripeWebhookController</c> which covers subscription billing events.
    /// Verifies the <c>Stripe-Signature</c> header against the Connect webhook secret before
    /// processing. Routes <c>payment_intent.succeeded</c> to either
    /// <see cref="HandlePaymentSucceededAsync"/> (invoice) or
    /// <see cref="HandleDepositPaymentSucceededAsync"/> (deposit) based on the <c>type</c> metadata
    /// key set when the PaymentIntent was created. Handles refund and chargeback events too.
    /// Returns HTTP 200 for all valid events — returning a non-2xx would cause Stripe to retry.
    /// </summary>
    [HttpPost("/stripe/connect-webhook")]
    [IgnoreAntiforgeryToken]
    public async Task<IActionResult> ConnectWebhook()
    {
        var json = await new StreamReader(HttpContext.Request.Body).ReadToEndAsync();
        var webhookSecret = _configuration["Stripe:Connect:ConnectWebhookSecret"]!;

        Event stripeEvent;
        try
        {
            stripeEvent = EventUtility.ConstructEvent(
                json, Request.Headers["Stripe-Signature"]!, webhookSecret);
        }
        catch (StripeException ex)
        {
            _logger.LogWarning("Invalid Stripe Connect webhook signature: {Message}", ex.Message);
            return BadRequest();
        }

        if (stripeEvent.Type == "payment_intent.succeeded")
        {
            var intent = stripeEvent.Data.Object as PaymentIntent;
            if (intent == null) return Ok();

            // Route deposit vs invoice payments by metadata discriminator
            intent.Metadata.TryGetValue("type", out var intentType);
            if (intentType == "deposit")
                await HandleDepositPaymentSucceededAsync(intent);
            else
                await HandlePaymentSucceededAsync(intent);
        }
        else if (stripeEvent.Type == "charge.refunded")
        {
            var charge = stripeEvent.Data.Object as Charge;
            if (charge != null) await HandleChargeRefundedAsync(charge);
        }
        else if (stripeEvent.Type == "charge.dispute.created")
        {
            var dispute = stripeEvent.Data.Object as Dispute;
            if (dispute != null) await HandleDisputeCreatedAsync(dispute);
        }
        else if (stripeEvent.Type == "charge.dispute.closed")
        {
            var dispute = stripeEvent.Data.Object as Dispute;
            if (dispute != null) await HandleDisputeClosedAsync(dispute);
        }

        return Ok();
    }

    // ─── Private helpers ─────────────────────────────────────────────────────

    /// <summary>
    /// Processes a successful <c>payment_intent.succeeded</c> Stripe Connect event for an invoice
    /// payment. Strips the surcharge out of the total (surcharge was stored in PI metadata by
    /// <see cref="CreateIntent"/>) so only the net amount is applied to <c>Invoice.AmountPaid</c>.
    /// Idempotency: skips if the PaymentIntent ID is already recorded with a paid/partial status to
    /// prevent double-recording on webhook retries. Uses <c>IgnoreQueryFilters</c> because the
    /// invoice belongs to a tenant company and this handler has no HTTP context / tenant claim.
    /// Fires email + in-app notifications after persisting, wrapped in separate try/catch blocks so a
    /// failed notification never rolls back the payment record.
    /// </summary>
    private async Task HandlePaymentSucceededAsync(PaymentIntent intent)
    {
        _logger.LogInformation("HandlePaymentSucceeded: PI={Id} Amount={Amount} Metadata={@Metadata}",
            intent.Id, intent.Amount, intent.Metadata);

        if (!intent.Metadata.TryGetValue("invoice_id", out var invoiceIdStr)
            || !int.TryParse(invoiceIdStr, out var invoiceId))
        {
            _logger.LogWarning("PaymentIntent {Id} has no invoice_id metadata", intent.Id);
            return;
        }

        _logger.LogInformation("HandlePaymentSucceeded: looking up invoice {InvoiceId}", invoiceId);

        var invoice = await _context.Invoices
            .IgnoreQueryFilters()
            .Include(i => i.Customer)
            .FirstOrDefaultAsync(i => i.Id == invoiceId && !i.IsDeleted);

        if (invoice == null)
        {
            _logger.LogWarning("PaymentIntent {Id} references unknown invoice {InvoiceId}", intent.Id, invoiceId);
            return;
        }

        _logger.LogInformation("HandlePaymentSucceeded: found invoice {InvoiceId} Status={Status} OnlineStatus={OnlineStatus} ExistingPI={ExistingPI}",
            invoiceId, invoice.Status, invoice.OnlinePaymentStatus, invoice.StripePaymentIntentId);

        // Idempotency guard — skip if this payment was already recorded
        if (invoice.StripePaymentIntentId == intent.Id && invoice.OnlinePaymentStatus is OnlinePaymentStatus.Paid or OnlinePaymentStatus.PartiallyPaid)
        {
            _logger.LogInformation("Duplicate webhook for PaymentIntent {Id} on invoice {InvoiceId} — skipping", intent.Id, invoiceId);
            return;
        }

        var amountPaidDollars = intent.Amount / 100m;
        decimal.TryParse(intent.Metadata.GetValueOrDefault("surcharge_amount", "0"), out var surcharge);
        var netPayment = amountPaidDollars - surcharge;

        invoice.OnlineAmountPaid += netPayment;
        invoice.OnlineSurchargeCollected += surcharge;
        invoice.AmountPaid += netPayment;
        invoice.StripePaymentIntentId = intent.Id;

        if (invoice.BalanceDue <= 0)
        {
            invoice.OnlinePaymentStatus = OnlinePaymentStatus.Paid;
            invoice.Status = InvoiceStatus.Paid;
            invoice.PaidDate = DateTime.UtcNow;
        }
        else
        {
            invoice.OnlinePaymentStatus = OnlinePaymentStatus.PartiallyPaid;
            invoice.Status = InvoiceStatus.PartiallyPaid;
        }

        invoice.UpdatedAt = DateTime.UtcNow;
        _context.Update(invoice);

        // Create a Payment record so the payment appears in AR and bank reports, and make the
        // matching GL entries. Manual payments go through RecordPayment which does the same thing;
        // this makes Stripe payments consistent with that path.
        var (arAcctId, checkingAcctId) = await GetGlAccountIdsAsync(invoice.CompanyId);
        var stripePayment = new Core.Entities.Payment
        {
            InvoiceId        = invoice.Id,
            Amount           = netPayment,
            PaymentDate      = DateTime.UtcNow,
            PaymentMethod    = PowderCoating.Core.Enums.PaymentMethod.CreditDebitCard,
            Reference        = intent.Id,
            Notes            = $"Online payment via Stripe. Surcharge: {surcharge:C}",
            DepositAccountId = checkingAcctId,
            CompanyId        = invoice.CompanyId,
            CreatedAt        = DateTime.UtcNow
        };
        _context.Payments.Add(stripePayment);

        await _context.SaveChangesAsync();

        await _accountBalanceService.DebitAsync(checkingAcctId, netPayment);
        await _accountBalanceService.CreditAsync(arAcctId, netPayment);

        _logger.LogInformation("Online payment of {Amount:C} received for invoice {InvoiceId}", amountPaidDollars, invoiceId);

        await _notificationService.NotifyOnlinePaymentReceivedAsync(invoice, netPayment, surcharge, intent.Id);

        try
        {
            var customerName = invoice.Customer?.CompanyName
                ?? $"{invoice.Customer?.ContactFirstName} {invoice.Customer?.ContactLastName}".Trim();
            await _inApp.CreateAsync(
                companyId: invoice.CompanyId,
                title: "Online Payment Received",
                message: $"{customerName} paid {netPayment:C} online for invoice {invoice.InvoiceNumber}.",
                notificationType: "InvoicePaid",
                link: $"/Invoices/Details/{invoice.Id}",
                invoiceId: invoice.Id,
                customerId: invoice.CustomerId);
        }
        catch (Exception ex)
        {
            _logger.LogWarning(ex, "In-app notification failed for online payment on invoice {InvoiceId}", invoiceId);
        }
    }

    /// <summary>
    /// Processes a successful <c>payment_intent.succeeded</c> event for a quote deposit. Creates a
    /// <c>Deposit</c> ledger record so the deposit appears in the customer's deposit history and can
    /// be auto-applied when an invoice is later created from the job. Deposit records are only created
    /// for quotes with a <c>CustomerId</c> (i.e. existing customers); prospect quotes skip the ledger
    /// entry because there is no Customer row to link to. The <c>DepositPaymentIntentId</c> check
    /// provides idempotency against webhook retries.
    /// </summary>
    private async Task HandleDepositPaymentSucceededAsync(PaymentIntent intent)
    {
        if (!intent.Metadata.TryGetValue("quote_id", out var quoteIdStr)
            || !int.TryParse(quoteIdStr, out var quoteId))
        {
            _logger.LogWarning("Deposit PaymentIntent {Id} has no quote_id metadata", intent.Id);
            return;
        }

        var quote = await _context.Quotes
            .IgnoreQueryFilters()
            .Include(q => q.Customer)
            .FirstOrDefaultAsync(q => q.Id == quoteId && !q.IsDeleted);

        if (quote == null)
        {
            _logger.LogWarning("Deposit PaymentIntent {Id} references unknown quote {QuoteId}", intent.Id, quoteId);
            return;
        }

        // Idempotency guard
        if (quote.DepositPaymentIntentId == intent.Id)
        {
            _logger.LogInformation("Duplicate deposit webhook for PaymentIntent {Id} on quote {QuoteId} — skipping", intent.Id, quoteId);
            return;
        }

        var amountPaidDollars = intent.Amount / 100m;
        decimal.TryParse(intent.Metadata.GetValueOrDefault("surcharge_amount", "0"), out var surcharge);
        var netDeposit = amountPaidDollars - surcharge;

        quote.DepositAmountPaid += netDeposit;
        quote.DepositPaymentIntentId = intent.Id;
        quote.UpdatedAt = DateTime.UtcNow;

        // Create a Deposit record so it shows up in the deposits ledger (customer quotes only)
        if (quote.CustomerId.HasValue)
        {
            var deposit = new Core.Entities.Deposit
            {
                CompanyId     = quote.CompanyId,
                CustomerId    = quote.CustomerId.Value,
                QuoteId       = quote.Id,
                Amount        = netDeposit,
                PaymentMethod = Core.Enums.PaymentMethod.CreditDebitCard,
                ReceivedDate  = DateTime.UtcNow,
                Reference     = intent.Id,
                Notes         = $"Online deposit via Stripe. Surcharge: {surcharge:C}",
                ReceiptNumber = $"DEP-{quote.QuoteNumber}-{DateTime.UtcNow:yyyyMMddHHmm}",
                CreatedAt     = DateTime.UtcNow
            };
            _context.Deposits.Add(deposit);
        }
        else
        {
            _logger.LogWarning("Deposit PaymentIntent {Id} on prospect quote {QuoteId} — Deposit record skipped (no CustomerId)", intent.Id, quoteId);
        }

        _context.Update(quote);
        await _context.SaveChangesAsync();

        _logger.LogInformation("Deposit of {Amount:C} received for quote {QuoteId}", amountPaidDollars, quoteId);

        try
        {
            await _notificationService.NotifyDepositReceivedAsync(quote, netDeposit, surcharge, intent.Id);
        }
        catch (Exception ex)
        {
            _logger.LogWarning(ex, "Failed to send deposit notification for quote {QuoteId}", quoteId);
        }

        try
        {
            var customerName = quote.Customer?.CompanyName
                ?? $"{quote.Customer?.ContactFirstName} {quote.Customer?.ContactLastName}".Trim();
            if (string.IsNullOrWhiteSpace(customerName))
                customerName = quote.ProspectCompanyName ?? quote.ProspectContactName ?? "Customer";
            await _inApp.CreateAsync(
                companyId: quote.CompanyId,
                title: "Online Deposit Received",
                message: $"{customerName} paid a {netDeposit:C} deposit online for quote {quote.QuoteNumber}.",
                notificationType: "InvoicePaid",
                link: $"/Quotes/Details/{quote.Id}",
                quoteId: quote.Id,
                customerId: quote.CustomerId);
        }
        catch (Exception ex)
        {
            _logger.LogWarning(ex, "In-app notification failed for online deposit on quote {QuoteId}", quoteId);
        }
    }

    /// <summary>
    /// Processes a <c>charge.refunded</c> Stripe event by creating a <c>Refund</c> ledger record and
    /// reversing the corresponding amount from <c>Invoice.AmountPaid</c>. Matches the invoice by
    /// <c>StripePaymentIntentId</c>, with a metadata fallback for cases where a later payment
    /// overwrote the PI on the invoice (e.g. partial pay → refund → partial pay again). Only the
    /// latest refund on the charge is processed per call; Stripe sends a separate event per refund
    /// so this is safe. The <c>Refund.Reference</c> column holds the Stripe refund ID and is used
    /// for idempotency checks.
    /// </summary>
    private async Task HandleChargeRefundedAsync(Charge charge)
    {
        if (string.IsNullOrEmpty(charge.PaymentIntentId))
        {
            _logger.LogWarning("Charge {ChargeId} refunded but has no PaymentIntentId", charge.Id);
            return;
        }

        var invoice = await _context.Invoices
            .IgnoreQueryFilters()
            .Include(i => i.Customer)
            .FirstOrDefaultAsync(i => i.StripePaymentIntentId == charge.PaymentIntentId && !i.IsDeleted);

        // Fallback: look up by invoice_id in charge metadata if the PaymentIntent was overwritten by a later payment
        if (invoice == null && charge.Metadata.TryGetValue("invoice_id", out var metaInvoiceIdStr)
            && int.TryParse(metaInvoiceIdStr, out var metaInvoiceId))
        {
            invoice = await _context.Invoices
                .IgnoreQueryFilters()
                .Include(i => i.Customer)
                .FirstOrDefaultAsync(i => i.Id == metaInvoiceId && !i.IsDeleted);
        }

        if (invoice == null)
        {
            _logger.LogWarning("charge.refunded for charge {ChargeId} (PI: {PI}) — invoice not found", charge.Id, charge.PaymentIntentId);
            return;
        }

        // Only process the latest refund on this charge
        var latestRefund = charge.Refunds?.Data?.OrderByDescending(r => r.Created).FirstOrDefault();
        if (latestRefund == null) return;

        // Idempotency: skip if this Stripe refund ID was already recorded
        var alreadyRecorded = await _context.Refunds
            .AnyAsync(r => r.InvoiceId == invoice.Id && r.Reference == latestRefund.Id && !r.IsDeleted);
        if (alreadyRecorded) return;

        var refundAmountDollars = latestRefund.Amount / 100m;

        var (arAcctIdR, checkingAcctIdR) = await GetGlAccountIdsAsync(invoice.CompanyId);

        var refund = new Core.Entities.Refund
        {
            CompanyId        = invoice.CompanyId,
            InvoiceId        = invoice.Id,
            Amount           = refundAmountDollars,
            RefundDate       = latestRefund.Created,
            RefundMethod     = Core.Enums.PaymentMethod.CreditDebitCard,
            Reason           = latestRefund.Reason ?? "Stripe refund",
            Reference        = latestRefund.Id,
            Notes            = $"Automatic refund via Stripe. PaymentIntent: {charge.PaymentIntentId}",
            Status           = Core.Enums.RefundStatus.Issued,
            IssuedDate       = DateTime.UtcNow,
            DepositAccountId = checkingAcctIdR,
            CreatedAt        = DateTime.UtcNow
        };
        _context.Refunds.Add(refund);

        invoice.OnlineAmountPaid  = Math.Max(0, invoice.OnlineAmountPaid - refundAmountDollars);
        invoice.AmountPaid        = Math.Max(0, invoice.AmountPaid - refundAmountDollars);

        if (invoice.AmountPaid <= 0)
        {
            invoice.OnlinePaymentStatus = OnlinePaymentStatus.Refunded;
            invoice.Status = InvoiceStatus.Sent;
            invoice.PaidDate = null;
        }
        else if (invoice.BalanceDue > 0)
        {
            invoice.OnlinePaymentStatus = OnlinePaymentStatus.PartiallyPaid;
            invoice.Status = InvoiceStatus.PartiallyPaid;
        }

        invoice.UpdatedAt = DateTime.UtcNow;
        _context.Update(invoice);
        await _context.SaveChangesAsync();

        // GL: DR AR (customer owes again) / CR Checking (cash left the bank)
        await _accountBalanceService.DebitAsync(arAcctIdR, refundAmountDollars);
        await _accountBalanceService.CreditAsync(checkingAcctIdR, refundAmountDollars);

        _logger.LogInformation("Refund of {Amount:C} recorded for invoice {InvoiceId} (Stripe refund {RefundId})",
            refundAmountDollars, invoice.Id, latestRefund.Id);
    }

    /// <summary>
    /// Processes a <c>charge.dispute.created</c> Stripe event. At this stage Stripe has not yet
    /// adjudicated the dispute, so no funds are reversed — only a chargeback alert notification is
    /// sent to the company so they can gather evidence. Reversal (if lost) is handled by
    /// <see cref="HandleDisputeClosedAsync"/>. Notification failure is caught and logged so a broken
    /// email config never causes Stripe to see a failed webhook and retry.
    /// </summary>
    private async Task HandleDisputeCreatedAsync(Dispute dispute)
    {
        var invoice = await FindInvoiceByPaymentIntentAsync(dispute.PaymentIntentId);
        if (invoice == null)
        {
            _logger.LogWarning("charge.dispute.created for dispute {DisputeId} — invoice not found (PI: {PI})",
                dispute.Id, dispute.PaymentIntentId);
            return;
        }

        var amount = dispute.Amount / 100m;
        _logger.LogWarning("Stripe dispute {DisputeId} opened on invoice {InvoiceId}, amount {Amount:C}, reason: {Reason}",
            dispute.Id, invoice.Id, amount, dispute.Reason);

        try
        {
            await _notificationService.NotifyChargebackAlertAsync(invoice, dispute.Id, amount, dispute.Reason ?? "unspecified");
        }
        catch (Exception ex)
        {
            _logger.LogWarning(ex, "Failed to send chargeback alert for invoice {InvoiceId}", invoice.Id);
        }
    }

    /// <summary>
    /// Processes a <c>charge.dispute.closed</c> Stripe event. Only acts when <c>dispute.Status ==
    /// "lost"</c> — won disputes require no accounting adjustment. On a lost dispute, the funds were
    /// already returned to the cardholder by Stripe, so a <c>Refund</c> ledger record is created and
    /// the invoice <c>AmountPaid</c> is reversed to reflect the true collected amount. The Stripe
    /// dispute ID is stored in <c>Refund.Reference</c> for idempotency — won disputes and duplicate
    /// webhook retries are both handled by the <c>alreadyRecorded</c> guard.
    /// </summary>
    private async Task HandleDisputeClosedAsync(Dispute dispute)
    {
        var invoice = await FindInvoiceByPaymentIntentAsync(dispute.PaymentIntentId);
        if (invoice == null)
        {
            _logger.LogWarning("charge.dispute.closed for dispute {DisputeId} — invoice not found (PI: {PI})",
                dispute.Id, dispute.PaymentIntentId);
            return;
        }

        _logger.LogInformation("Stripe dispute {DisputeId} closed with status '{Status}' on invoice {InvoiceId}",
            dispute.Id, dispute.Status, invoice.Id);

        if (dispute.Status == "lost")
        {
            // Idempotency: skip if already recorded
            var alreadyRecorded = await _context.Refunds
                .AnyAsync(r => r.InvoiceId == invoice.Id && r.Reference == dispute.Id && !r.IsDeleted);
            if (alreadyRecorded) return;

            var amount = dispute.Amount / 100m;
            var (arAcctIdD, checkingAcctIdD) = await GetGlAccountIdsAsync(invoice.CompanyId);

            var refund = new Core.Entities.Refund
            {
                CompanyId        = invoice.CompanyId,
                InvoiceId        = invoice.Id,
                Amount           = amount,
                RefundDate       = DateTime.UtcNow,
                RefundMethod     = Core.Enums.PaymentMethod.CreditDebitCard,
                Reason           = "Chargeback lost — funds returned to customer",
                Reference        = dispute.Id,
                Notes            = $"Automatic chargeback loss via Stripe. Dispute ID: {dispute.Id}",
                Status           = Core.Enums.RefundStatus.Issued,
                IssuedDate       = DateTime.UtcNow,
                DepositAccountId = checkingAcctIdD,
                CreatedAt        = DateTime.UtcNow
            };
            _context.Refunds.Add(refund);

            invoice.OnlineAmountPaid = Math.Max(0, invoice.OnlineAmountPaid - amount);
            invoice.AmountPaid       = Math.Max(0, invoice.AmountPaid - amount);

            if (invoice.AmountPaid <= 0)
            {
                invoice.OnlinePaymentStatus = OnlinePaymentStatus.Refunded;
                invoice.Status = InvoiceStatus.Sent;
                invoice.PaidDate = null;
            }
            else if (invoice.BalanceDue > 0)
            {
                invoice.OnlinePaymentStatus = OnlinePaymentStatus.PartiallyPaid;
                invoice.Status = InvoiceStatus.PartiallyPaid;
            }

            invoice.UpdatedAt = DateTime.UtcNow;
            _context.Update(invoice);
            await _context.SaveChangesAsync();

            await _accountBalanceService.DebitAsync(arAcctIdD, amount);
            await _accountBalanceService.CreditAsync(checkingAcctIdD, amount);

            _logger.LogWarning("Chargeback lost for invoice {InvoiceId}, {Amount:C} reversed", invoice.Id, amount);
        }
    }

    /// <summary>
    /// Looks up an invoice by its stored <c>StripePaymentIntentId</c>. Used by dispute handlers
    /// where the invoice ID is not in the Stripe metadata. <c>IgnoreQueryFilters</c> is required
    /// because there is no authenticated tenant context in webhook handlers.
    /// </summary>
    /// <summary>
    /// Resolves the primary AR and Checking/Cash account IDs for a company, used by webhook handlers
    /// to make GL entries without an authenticated tenant context. Returns nulls gracefully so
    /// IAccountBalanceService.DebitAsync/CreditAsync silently skips missing accounts.
    /// </summary>
    private async Task<(int? ArAccountId, int? CheckingAccountId)> GetGlAccountIdsAsync(int companyId)
    {
        var ar = await _context.Accounts
            .Where(a => a.CompanyId == companyId && a.IsActive && !a.IsDeleted
                     && a.AccountSubType == AccountSubTypeEnum.AccountsReceivable)
            .Select(a => (int?)a.Id)
            .FirstOrDefaultAsync();
        var checking = await _context.Accounts
            .Where(a => a.CompanyId == companyId && a.IsActive && !a.IsDeleted
                     && (a.AccountSubType == AccountSubTypeEnum.Checking
                      || a.AccountSubType == AccountSubTypeEnum.Cash))
            .Select(a => (int?)a.Id)
            .FirstOrDefaultAsync();
        return (ar, checking);
    }

    private async Task<Core.Entities.Invoice?> FindInvoiceByPaymentIntentAsync(string? paymentIntentId)
    {
        if (string.IsNullOrEmpty(paymentIntentId)) return null;
        return await _context.Invoices
            .IgnoreQueryFilters()
            .Include(i => i.Customer)
            .FirstOrDefaultAsync(i => i.StripePaymentIntentId == paymentIntentId && !i.IsDeleted);
    }

    /// <summary>
    /// Validates an invoice payment token and returns the associated invoice and company, or an
    /// error message. This is the central guard for all invoice payment actions — token expiry,
    /// zero balance, voided status, and inactive Stripe Connect are all checked here. The method uses
    /// <c>IgnoreQueryFilters</c> because the token is accessed by unauthenticated customers and the
    /// normal multi-tenancy filter would block the query. Callers short-circuit on non-null error.
    /// </summary>
    private async Task<(Core.Entities.Invoice? Invoice, Core.Entities.Company? Company, string? Error)>
        ResolveInvoiceFromTokenAsync(string token)
    {
        var invoice = await _context.Invoices
            .IgnoreQueryFilters()
            .FirstOrDefaultAsync(i => i.PaymentLinkToken == token && !i.IsDeleted);

        if (invoice == null)
            return (null, null, "This payment link is not valid.");

        if (invoice.PaymentLinkExpiresAt < DateTime.UtcNow)
            return (null, null, "This payment link has expired. Please contact the shop for a new link.");

        if (invoice.BalanceDue <= 0)
            return (null, null, "This invoice has already been paid in full.");

        if (invoice.Status == InvoiceStatus.Voided)
            return (null, null, "This invoice has been voided and is no longer payable.");

        var company = await _context.Companies.AsNoTracking()
            .FirstOrDefaultAsync(c => c.Id == invoice.CompanyId && !c.IsDeleted);

        if (company == null || company.StripeConnectStatus != Core.Enums.StripeConnectStatus.Active)
            return (null, null, "Online payments are not available for this invoice.");

        return (invoice, company, null);
    }

    /// <summary>
    /// Validates a deposit payment token and returns the associated quote and company, or an error
    /// message. Mirrors <see cref="ResolveInvoiceFromTokenAsync"/> for the deposit flow. Checks that
    /// the quote deposit has not already been fully paid (compares <c>DepositAmountPaid</c> against
    /// the computed deposit amount) so the link cannot be reused after a successful payment.
    /// </summary>
    private async Task<(Core.Entities.Quote? Quote, Core.Entities.Company? Company, string? Error)>
        ResolveDepositQuoteFromTokenAsync(string token)
    {
        var quote = await _context.Quotes
            .IgnoreQueryFilters()
            .Include(q => q.Customer)
            .FirstOrDefaultAsync(q => q.DepositPaymentLinkToken == token && !q.IsDeleted);

        if (quote == null)
            return (null, null, "This deposit payment link is not valid.");

        if (quote.DepositPaymentLinkExpiresAt < DateTime.UtcNow)
            return (null, null, "This deposit payment link has expired. Please contact the shop for a new link.");

        var depositRequired = Math.Round(quote.Total * (quote.DepositPercent / 100m), 2);
        if (quote.DepositAmountPaid >= depositRequired)
            return (null, null, "This deposit has already been paid.");

        var company = await _context.Companies.AsNoTracking()
            .FirstOrDefaultAsync(c => c.Id == quote.CompanyId && !c.IsDeleted);

        if (company == null || company.StripeConnectStatus != Core.Enums.StripeConnectStatus.Active)
            return (null, null, "Online payments are not available for this deposit.");

        return (quote, company, null);
    }

    /// <summary>
    /// Calculates the online payment surcharge to add to the customer-facing total. Companies can
    /// configure either a percentage surcharge (e.g. 3% credit card fee pass-through) or a flat
    /// surcharge (e.g. $2.00 handling fee) via <c>OnlinePaymentSurchargeType</c> and
    /// <c>OnlinePaymentSurchargeValue</c>. Returns 0 for any other surcharge type (including
    /// <c>None</c>). The surcharge amount is passed in Stripe metadata so the webhook can strip it
    /// back out when crediting the net amount to the invoice.
    /// </summary>
    private static decimal CalculateSurcharge(decimal amount, Core.Entities.Company company)
    {
        return company.OnlinePaymentSurchargeType switch
        {
            OnlinePaymentSurchargeType.Percent =>
                Math.Round(amount * (company.OnlinePaymentSurchargeValue / 100m), 2),
            OnlinePaymentSurchargeType.Flat =>
                company.OnlinePaymentSurchargeValue,
            _ => 0m
        };
    }
}

// ─── View models & request DTOs ──────────────────────────────────────────────

public class PaymentPageViewModel
{
    public string InvoiceNumber { get; set; } = string.Empty;
    public int InvoiceId { get; set; }
    public string Token { get; set; } = string.Empty;
    public string CustomerName { get; set; } = string.Empty;
    public string CustomerEmail { get; set; } = string.Empty;
    public string CompanyName { get; set; } = string.Empty;
    public decimal BalanceDue { get; set; }
    public decimal InvoiceTotal { get; set; }
    public decimal AmountPaid { get; set; }
    public OnlinePaymentSurchargeType SurchargeType { get; set; }
    public decimal SurchargeValue { get; set; }
    public decimal SurchargeAmount { get; set; }
    public decimal TotalWithSurcharge { get; set; }
    public DateTime ExpiresAt { get; set; }
    public bool IsFullyPaid { get; set; }
    public string StripePublishableKey { get; set; } = string.Empty;
    public string StripeAccountId { get; set; } = string.Empty;
}

public class DepositPaymentPageViewModel
{
    public string QuoteNumber          { get; set; } = string.Empty;
    public int    QuoteId              { get; set; }
    public string Token                { get; set; } = string.Empty;
    public string CustomerName         { get; set; } = string.Empty;
    public string CustomerEmail        { get; set; } = string.Empty;
    public string CompanyName          { get; set; } = string.Empty;
    public decimal DepositAmount       { get; set; }
    public decimal QuoteTotal          { get; set; }
    public decimal DepositPercent      { get; set; }
    public OnlinePaymentSurchargeType SurchargeType  { get; set; }
    public decimal SurchargeValue      { get; set; }
    public decimal SurchargeAmount     { get; set; }
    public decimal TotalWithSurcharge  { get; set; }
    public DateTime ExpiresAt          { get; set; }
    public string StripePublishableKey { get; set; } = string.Empty;
    public string StripeAccountId      { get; set; } = string.Empty;
}

public class InvoiceViewViewModel
{
    public string InvoiceNumber  { get; set; } = string.Empty;
    public DateTime InvoiceDate  { get; set; }
    public DateTime? DueDate     { get; set; }
    public string CustomerName   { get; set; } = string.Empty;
    public string CompanyName    { get; set; } = string.Empty;
    public string? CompanyPhone  { get; set; }
    public string? CompanyAddress { get; set; }
    public string? LogoFilePath  { get; set; }
    public decimal SubTotal      { get; set; }
    public decimal TaxPercent    { get; set; }
    public decimal TaxAmount     { get; set; }
    public decimal DiscountAmount { get; set; }
    public decimal Total         { get; set; }
    public decimal AmountPaid    { get; set; }
    public decimal BalanceDue    { get; set; }
    public InvoiceStatus Status  { get; set; }
    public string? Notes         { get; set; }
    public string? Terms         { get; set; }
    public string? JobNumber     { get; set; }
    public string? PaymentUrl    { get; set; }
    public List<InvoiceViewLineItem> LineItems { get; set; } = new();
}

public class InvoiceViewLineItem
{
    public string Description { get; set; } = string.Empty;
    public decimal Quantity   { get; set; }
    public decimal UnitPrice  { get; set; }
    public decimal TotalPrice  { get; set; }
}

public class CreateIntentRequest
{
    public decimal Amount { get; set; }
}