using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using PowderCoating.Application.Interfaces;
using PowderCoating.Core.Enums;
using PowderCoating.Core.Interfaces;
using Stripe;

namespace PowderCoating.Infrastructure.Services;

/// <summary>
/// Implements Stripe Connect OAuth onboarding and embedded payment processing for tenants.
/// Each tenant company gets its own Stripe Connect account; payments made by their end customers
/// go directly into that connected account. The platform uses the OAuth flow (not the hosted
/// onboarding link) so tenants can connect an existing Stripe account rather than creating a new one.
/// Connect status on the <c>Company</c> entity uses <see cref="StripeConnectStatus"/>:
/// NotStarted → Pending (OAuth started) → Active (token exchanged) → Deauthorized (tenant revoked).
/// </summary>
public class StripeConnectService : IStripeConnectService
{
    private readonly IConfiguration _configuration;
    private readonly IUnitOfWork _unitOfWork;
    private readonly ILogger<StripeConnectService> _logger;

    /// <summary>Secret key for the Connect platform Stripe account (separate from the subscription secret key).</summary>
    private string SecretKey => _configuration["Stripe:Connect:SecretKey"]!;

    /// <summary>OAuth client ID (ca_...) of the platform's Connect application in the Stripe dashboard.</summary>
    private string ConnectClientId => _configuration["Stripe:Connect:ConnectClientId"]!;

    /// <summary>
    /// Constructs the service. Configuration values are read lazily via properties rather than
    /// cached in the constructor so that configuration changes in integration tests take effect
    /// without rebuilding the DI container.
    /// </summary>
    public StripeConnectService(
        IConfiguration configuration,
        IUnitOfWork unitOfWork,
        ILogger<StripeConnectService> logger)
    {
        _configuration = configuration;
        _unitOfWork = unitOfWork;
        _logger = logger;
    }

    /// <summary>
    /// Builds the Stripe Connect OAuth authorization URL that the tenant's admin is redirected to.
    /// The <paramref name="companyId"/> is passed as the OAuth <c>state</c> parameter so the
    /// callback endpoint can identify which company is completing onboarding without relying on
    /// session state, which may be lost if the browser opens a new tab for the Stripe flow.
    /// <c>scope=read_write</c> is required to create charges on behalf of the connected account.
    /// </summary>
    public string GetOAuthUrl(int companyId, string redirectUri)
    {
        var state = companyId.ToString(); // passed back in callback to identify the company
        return $"https://connect.stripe.com/oauth/authorize" +
               $"?response_type=code" +
               $"&client_id={ConnectClientId}" +
               $"&scope=read_write" +
               $"&redirect_uri={Uri.EscapeDataString(redirectUri)}" +
               $"&state={state}";
    }

    /// <summary>
    /// Completes the Stripe Connect OAuth flow by exchanging the one-time authorization
    /// <paramref name="code"/> for a permanent Stripe account ID (<c>stripe_user_id</c>).
    /// Persists the account ID on the company and sets <see cref="StripeConnectStatus.Active"/>.
    /// Returns a structured result tuple rather than throwing so the controller can surface a
    /// user-friendly error message without catching exceptions. Stripe errors (invalid code,
    /// already used code, etc.) are caught as <see cref="StripeException"/> and returned as
    /// a failure with the Stripe error message.
    /// </summary>
    public async Task<(bool Success, string? ErrorMessage)> HandleOAuthCallbackAsync(string code, int companyId)
    {
        try
        {
            var client = new StripeClient(SecretKey);
            var oauthService = new OAuthTokenService(client);
            var response = await oauthService.CreateAsync(new OAuthTokenCreateOptions
            {
                GrantType = "authorization_code",
                Code = code
            });

            var company = await _unitOfWork.Companies.GetByIdAsync(companyId, ignoreQueryFilters: true);
            if (company == null)
                return (false, "Company not found.");

            company.StripeAccountId = response.StripeUserId;
            company.StripeConnectStatus = StripeConnectStatus.Active;
            company.UpdatedAt = DateTime.UtcNow;

            await _unitOfWork.Companies.UpdateAsync(company);
            await _unitOfWork.CompleteAsync();

            _logger.LogInformation("Company {CompanyId} connected Stripe account {AccountId}", companyId, response.StripeUserId);
            return (true, null);
        }
        catch (StripeException ex)
        {
            _logger.LogError(ex, "Stripe OAuth error for company {CompanyId}", companyId);
            return (false, ex.StripeError?.Message ?? ex.Message);
        }
    }

    /// <summary>
    /// Deauthorizes the tenant's connected Stripe account and clears the stored account ID.
    /// The Stripe deauthorize call revokes the platform's access token, preventing any future
    /// charges on behalf of the tenant. If the company has no stored account ID the Stripe call
    /// is skipped (e.g. partially-onboarded company) and only the local record is cleared.
    /// Sets <see cref="StripeConnectStatus.NotConnected"/> on the company record so the UI
    /// correctly shows the "Connect Stripe" button again.
    /// </summary>
    public async Task<(bool Success, string? ErrorMessage)> DisconnectAsync(int companyId)
    {
        try
        {
            var company = await _unitOfWork.Companies.GetByIdAsync(companyId, ignoreQueryFilters: true);
            if (company == null)
                return (false, "Company not found.");

            if (!string.IsNullOrEmpty(company.StripeAccountId))
            {
                var client = new StripeClient(SecretKey);
                var oauthService = new OAuthTokenService(client);
                await oauthService.DeauthorizeAsync(new OAuthDeauthorizeOptions
                {
                    ClientId = ConnectClientId,
                    StripeUserId = company.StripeAccountId
                });
            }

            company.StripeAccountId = null;
            company.StripeConnectStatus = StripeConnectStatus.NotConnected;
            company.UpdatedAt = DateTime.UtcNow;

            await _unitOfWork.Companies.UpdateAsync(company);
            await _unitOfWork.CompleteAsync();

            _logger.LogInformation("Company {CompanyId} disconnected Stripe account", companyId);
            return (true, null);
        }
        catch (StripeException ex)
        {
            _logger.LogError(ex, "Stripe disconnect error for company {CompanyId}", companyId);
            return (false, ex.StripeError?.Message ?? ex.Message);
        }
    }

    /// <summary>
    /// Creates a Stripe PaymentIntent on the tenant's connected account so the customer can pay
    /// their invoice online via embedded Stripe Elements in the customer portal. The intent is
    /// created with <c>StripeAccount</c> set to <paramref name="connectedAccountId"/> so funds
    /// settle directly into the tenant's Stripe account rather than the platform account.
    /// The optional <paramref name="surchargeAmount"/> (credit-card processing fee pass-through)
    /// is added to the invoice total before converting to cents; the surcharge is stored in
    /// intent metadata so the fulfillment logic can record it separately. Returns the
    /// <c>client_secret</c> (needed by Stripe.js on the client) and the <c>PaymentIntentId</c>
    /// (needed to confirm the payment server-side).
    /// </summary>
    public async Task<(bool Success, string? ClientSecret, string? PaymentIntentId, string? ErrorMessage)> CreatePaymentIntentAsync(
        string connectedAccountId,
        decimal invoiceTotal,
        decimal surchargeAmount,
        string currency,
        string invoiceNumber,
        int invoiceId)
    {
        try
        {
            var totalWithSurcharge = invoiceTotal + surchargeAmount;
            var amountInCents = (long)Math.Round(totalWithSurcharge * 100, MidpointRounding.AwayFromZero);

            var options = new PaymentIntentCreateOptions
            {
                Amount = amountInCents,
                Currency = currency.ToLower(),
                Description = $"Invoice {invoiceNumber}",
                Metadata = new Dictionary<string, string>
                {
                    { "invoice_id", invoiceId.ToString() },
                    { "invoice_number", invoiceNumber },
                    { "surcharge_amount", surchargeAmount.ToString("F2") }
                },
                AutomaticPaymentMethods = new PaymentIntentAutomaticPaymentMethodsOptions
                {
                    Enabled = true
                }
            };

            var client = new StripeClient(SecretKey);
            var requestOptions = new RequestOptions { StripeAccount = connectedAccountId };
            var service = new PaymentIntentService(client);
            var intent = await service.CreateAsync(options, requestOptions);

            return (true, intent.ClientSecret, intent.Id, null);
        }
        catch (StripeException ex)
        {
            _logger.LogError(ex, "Failed to create PaymentIntent for invoice {InvoiceId}", invoiceId);
            return (false, null, null, ex.StripeError?.Message ?? ex.Message);
        }
    }

    /// <summary>
    /// Creates a Stripe PaymentIntent for a quote deposit on the tenant's connected account.
    /// Mirrors <see cref="CreatePaymentIntentAsync"/> but attaches <c>type=deposit</c> and
    /// <c>quote_id</c> metadata instead of invoice metadata so the payment confirmation handler
    /// can route the received funds to the <c>Deposits</c> table rather than as an invoice
    /// payment. Deposits can later be auto-applied to the invoice when it is created.
    /// </summary>
    public async Task<(bool Success, string? ClientSecret, string? PaymentIntentId, string? ErrorMessage)> CreateDepositPaymentIntentAsync(
        string connectedAccountId,
        decimal depositAmount,
        decimal surchargeAmount,
        string currency,
        string quoteNumber,
        int quoteId)
    {
        try
        {
            var totalWithSurcharge = depositAmount + surchargeAmount;
            var amountInCents = (long)Math.Round(totalWithSurcharge * 100, MidpointRounding.AwayFromZero);

            var options = new PaymentIntentCreateOptions
            {
                Amount = amountInCents,
                Currency = currency.ToLower(),
                Description = $"Deposit for quote {quoteNumber}",
                Metadata = new Dictionary<string, string>
                {
                    { "type",             "deposit" },
                    { "quote_id",         quoteId.ToString() },
                    { "quote_number",     quoteNumber },
                    { "surcharge_amount", surchargeAmount.ToString("F2") }
                },
                AutomaticPaymentMethods = new PaymentIntentAutomaticPaymentMethodsOptions
                {
                    Enabled = true
                }
            };

            var client = new StripeClient(SecretKey);
            var requestOptions = new RequestOptions { StripeAccount = connectedAccountId };
            var service = new PaymentIntentService(client);
            var intent = await service.CreateAsync(options, requestOptions);

            return (true, intent.ClientSecret, intent.Id, null);
        }
        catch (StripeException ex)
        {
            _logger.LogError(ex, "Failed to create deposit PaymentIntent for quote {QuoteId}", quoteId);
            return (false, null, null, ex.StripeError?.Message ?? ex.Message);
        }
    }

}