using System.Collections.Concurrent;

namespace Campaign_Tracker.Server.Municipalities;

public sealed class InMemoryMunicipalityContactRepository : IMunicipalityContactRepository
{
    private static readonly Dictionary<string, int> ContactTypeSortOrder =
        new(StringComparer.OrdinalIgnoreCase)
        {
            ["Primary"] = 0,
            ["Secondary"] = 1,
        };

    private readonly ConcurrentDictionary<string, MunicipalityContact> _contacts =
        new(StringComparer.OrdinalIgnoreCase);
    private readonly object _lock = new();
    private readonly TimeProvider _timeProvider;

    public InMemoryMunicipalityContactRepository(TimeProvider timeProvider)
    {
        _timeProvider = timeProvider;
    }

    public Task<IReadOnlyList<MunicipalityContact>> GetByProfileIdAsync(
        string profileId,
        CancellationToken cancellationToken = default)
    {
        var result = _contacts.Values
            .Where(c => c.ProfileId == profileId && !c.IsDeleted)
            .OrderBy(c => ContactTypeSortOrder.GetValueOrDefault(c.ContactType, 99))
            .ThenBy(c => c.Name, StringComparer.OrdinalIgnoreCase)
            .ToArray();
        return Task.FromResult<IReadOnlyList<MunicipalityContact>>(result);
    }

    public Task<MunicipalityContact?> GetByIdAsync(
        string contactId,
        CancellationToken cancellationToken = default)
    {
        _contacts.TryGetValue(contactId, out var contact);
        return Task.FromResult(contact is { IsDeleted: false } ? contact : null);
    }

    public Task<MunicipalityContactSaveResult> AddAsync(
        string profileId,
        string contactType,
        string name,
        string? roleTitle,
        string? phone,
        string? email,
        string actorIdentity,
        CancellationToken cancellationToken = default)
    {
        var validation = Validate(contactType, name);
        if (validation is not null)
            return Task.FromResult(MunicipalityContactSaveResult.Failure(validation));

        var now = _timeProvider.GetUtcNow();
        var contact = new MunicipalityContact(
            ContactId: Guid.NewGuid().ToString("N"),
            ProfileId: profileId,
            ContactType: NormalizeContactType(contactType),
            Name: name.Trim(),
            RoleTitle: NormalizeOptional(roleTitle),
            Phone: NormalizeOptional(phone),
            Email: NormalizeOptional(email),
            IsDeleted: false,
            CreatedAt: now,
            CreatedBy: actorIdentity,
            UpdatedAt: now,
            UpdatedBy: actorIdentity);

        _contacts[contact.ContactId] = contact;
        return Task.FromResult(MunicipalityContactSaveResult.Success(contact));
    }

    public Task<MunicipalityContactSaveResult> UpdateAsync(
        string contactId,
        string contactType,
        string name,
        string? roleTitle,
        string? phone,
        string? email,
        string actorIdentity,
        CancellationToken cancellationToken = default)
    {
        var validation = Validate(contactType, name);
        if (validation is not null)
            return Task.FromResult(MunicipalityContactSaveResult.Failure(validation));

        var now = _timeProvider.GetUtcNow();

        lock (_lock)
        {
            if (!_contacts.TryGetValue(contactId, out var existing) || existing.IsDeleted)
                return Task.FromResult(MunicipalityContactSaveResult.NotFound(contactId));

            var updated = existing with
            {
                ContactType = NormalizeContactType(contactType),
                Name = name.Trim(),
                RoleTitle = NormalizeOptional(roleTitle),
                Phone = NormalizeOptional(phone),
                Email = NormalizeOptional(email),
                UpdatedAt = now,
                UpdatedBy = actorIdentity,
            };
            _contacts[contactId] = updated;
            return Task.FromResult(MunicipalityContactSaveResult.Success(updated));
        }
    }

    public Task<MunicipalityContactSaveResult> SoftDeleteAsync(
        string contactId,
        string actorIdentity,
        CancellationToken cancellationToken = default)
    {
        var now = _timeProvider.GetUtcNow();

        lock (_lock)
        {
            if (!_contacts.TryGetValue(contactId, out var existing) || existing.IsDeleted)
                return Task.FromResult(MunicipalityContactSaveResult.NotFound(contactId));

            var deleted = existing with
            {
                IsDeleted = true,
                UpdatedAt = now,
                UpdatedBy = actorIdentity,
            };
            _contacts[contactId] = deleted;
            return Task.FromResult(MunicipalityContactSaveResult.Success(deleted));
        }
    }

    private static string? Validate(string contactType, string name)
    {
        if (string.IsNullOrWhiteSpace(name))
            return "Name is required.";

        if (string.IsNullOrWhiteSpace(contactType))
            return "Contact type is required.";

        if (!ContactTypeSortOrder.ContainsKey(contactType.Trim()))
            return "Contact type must be Primary or Secondary.";

        return null;
    }

    private static string NormalizeContactType(string contactType) =>
        string.Equals(contactType.Trim(), "Primary", StringComparison.OrdinalIgnoreCase)
            ? "Primary"
            : "Secondary";

    private static string? NormalizeOptional(string? value) =>
        string.IsNullOrWhiteSpace(value) ? null : value.Trim();
}