using Registration.Data;
using System.Collections.Concurrent;
using Microsoft.Extensions.Logging;

namespace Registration.Mock;

/// <summary>
/// In-memory mock registration data for development.
/// Persists across requests within a single Function host lifecycle.
/// State resets on cold start (by design — it's mock data).
///
/// Swap to SqlDataService in Program.cs when dbRegistration is ready.
/// </summary>
public class MockDataService : IRegistrationDataService
{
    private readonly ConcurrentDictionary<string, Applicant> _store;
    private readonly ILogger<MockDataService> _log;

    public MockDataService(ILogger<MockDataService> log)
    {
        _log = log;
        _store = new ConcurrentDictionary<string, Applicant>(SeedData());
        _log.LogInformation("[Mock] Initialized with {Count} applicants", _store.Count);
    }

    public Task<RegistrationListResult> GetPendingAsync(CancellationToken ct)
    {
        var pending = _store.Values
            .Where(a => a.Status == "Pending")
            .OrderBy(a => a.RegisteredUtc)
            .ToList();

        return Task.FromResult(new RegistrationListResult
        {
            Ok = true,
            Applicants = pending,
            TotalCount = pending.Count
        });
    }

    public Task<Applicant?> GetByIdAsync(string registrationId, CancellationToken ct)
    {
        _store.TryGetValue(registrationId, out var applicant);
        return Task.FromResult(applicant);
    }

    public Task<RegistrationResult> RegisterAsync(RegisterRequest request, CancellationToken ct)
    {
        if (string.IsNullOrWhiteSpace(request.BusinessName))
            return Task.FromResult(new RegistrationResult { Ok = false, Error = "Business name is required" });

        // Check for duplicate business name
        if (_store.Values.Any(a => string.Equals(a.BusinessName, request.BusinessName, StringComparison.OrdinalIgnoreCase)
            && a.Status != "Rejected"))
            return Task.FromResult(new RegistrationResult { Ok = false, Error = "A registration with this name already exists" });

        var id = Guid.NewGuid().ToString("D");
        var applicant = new Applicant
        {
            RegistrationId = id,
            BusinessName = request.BusinessName!.Trim(),
            WebsiteUrl = request.WebsiteUrl,
            BusinessCategory = request.BusinessCategory,
            BusinessDescription = request.BusinessDescription,
            ContactName = request.ContactName,
            ContactEmail = request.ContactEmail,
            ContactPhone = request.ContactPhone,
            EntraSubjectId = request.EntraSubjectId,
            Status = "Pending",
            PaymentVerified = false,
            RegisteredUtc = DateTime.UtcNow
        };

        _store[id] = applicant;
        _log.LogInformation("[Mock] New registration: {Name} ({Id})", applicant.BusinessName, id);

        return Task.FromResult(new RegistrationResult { Ok = true, RegistrationId = id });
    }

    public Task<RegistrationResult> RejectAsync(string registrationId, string? reason, string? rejectedBy, CancellationToken ct)
    {
        if (!_store.TryGetValue(registrationId, out var applicant))
            return Task.FromResult(new RegistrationResult { Ok = false, Error = "Registration not found" });

        if (applicant.Status != "Pending")
            return Task.FromResult(new RegistrationResult { Ok = false, Error = $"Cannot reject — status is {applicant.Status}" });

        applicant.Status = "Rejected";
        applicant.RejectionReason = reason;
        applicant.ReviewedBy = rejectedBy;
        applicant.ReviewedUtc = DateTime.UtcNow;

        _log.LogInformation("[Mock] Rejected: {Name} ({Id}) reason={Reason}", applicant.BusinessName, registrationId, reason);

        return Task.FromResult(new RegistrationResult { Ok = true, RegistrationId = registrationId });
    }

    public Task<RegistrationResult> CompleteAsync(string registrationId, string? platformClientId, CancellationToken ct)
    {
        if (!_store.TryGetValue(registrationId, out var applicant))
            return Task.FromResult(new RegistrationResult { Ok = false, Error = "Registration not found" });

        if (applicant.Status != "Pending")
            return Task.FromResult(new RegistrationResult { Ok = false, Error = $"Cannot complete — status is {applicant.Status}" });

        applicant.Status = "Approved";
        applicant.PlatformClientId = platformClientId;
        applicant.ReviewedUtc = DateTime.UtcNow;

        _log.LogInformation("[Mock] Approved: {Name} ({Id}) → platform client {PlatformId}",
            applicant.BusinessName, registrationId, platformClientId);

        return Task.FromResult(new RegistrationResult { Ok = true, RegistrationId = registrationId });
    }

    // ── Seed Data ───────────────────────────────────

    private static IEnumerable<KeyValuePair<string, Applicant>> SeedData()
    {
        var applicants = new[]
        {
            new Applicant
            {
                RegistrationId = "reg-001",
                BusinessName = "Bella's Boutique",
                WebsiteUrl = "https://bellasboutique.com",
                BusinessCategory = "retail",
                BusinessDescription = "Women's fashion and accessories boutique in Orange County. Looking to expand online presence through targeted social and search ads.",
                ContactName = "Bella Rodriguez",
                ContactEmail = "bella@bellasboutique.com",
                ContactPhone = "(714) 555-0142",
                EntraSubjectId = "entra-mock-bella-001",
                Status = "Pending",
                PaymentVerified = true,
                RegisteredUtc = DateTime.UtcNow.AddDays(-3)
            },
            new Applicant
            {
                RegistrationId = "reg-002",
                BusinessName = "Pacific Coast Plumbing",
                WebsiteUrl = "https://pacificcoastplumbing.com",
                BusinessCategory = "home_services",
                BusinessDescription = "Full-service plumbing company serving LA and OC. Need help with Google Local Services ads and Maps visibility.",
                ContactName = "Mike Chen",
                ContactEmail = "mike@pcplumbing.com",
                ContactPhone = "(562) 555-0198",
                EntraSubjectId = "entra-mock-mike-002",
                Status = "Pending",
                PaymentVerified = true,
                RegisteredUtc = DateTime.UtcNow.AddDays(-1)
            },
            new Applicant
            {
                RegistrationId = "reg-003",
                BusinessName = "Sunrise Dental Group",
                WebsiteUrl = "https://sunrisedental.care",
                BusinessCategory = "healthcare",
                BusinessDescription = "Multi-location dental practice. Interested in running awareness campaigns for new patient acquisition across Google and Meta.",
                ContactName = "Dr. Sarah Kim",
                ContactEmail = "sarah@sunrisedental.care",
                ContactPhone = "(949) 555-0267",
                EntraSubjectId = "entra-mock-sarah-003",
                Status = "Pending",
                PaymentVerified = false,
                RegisteredUtc = DateTime.UtcNow.AddHours(-6)
            },
            new Applicant
            {
                RegistrationId = "reg-004",
                BusinessName = "FreshBite Meal Prep",
                WebsiteUrl = "https://freshbitemealprep.com",
                BusinessCategory = "food_beverage",
                BusinessDescription = "Healthy meal prep delivery service. $2k/month budget for Instagram and TikTok ads targeting health-conscious millennials.",
                ContactName = "Jordan Williams",
                ContactEmail = "jordan@freshbitemealprep.com",
                ContactPhone = "(310) 555-0334",
                EntraSubjectId = "entra-mock-jordan-004",
                Status = "Pending",
                PaymentVerified = true,
                RegisteredUtc = DateTime.UtcNow.AddHours(-2)
            },
        };

        return applicants.Select(a => new KeyValuePair<string, Applicant>(a.RegistrationId, a));
    }
}