using System.Net.Http;
using System.Net.Http.Json;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace ytLive.Services;

/// <summary>
/// Validates LlamaCasty license keys against the Polar.sh customer-portal API.
/// No auth required for client-side validation — the endpoint is public by design.
/// </summary>
public class PolarLicenseService
{
    private const string ValidateUrl = "https://api.polar.sh/v1/customer-portal/license-keys/validate";
    public const string OrganizationId = "c05fb364-b967-4f6c-adf2-8a144e46d085";

    private readonly HttpClient _http;

    public PolarLicenseService(HttpClient? http = null)
    {
        _http = http ?? new HttpClient { Timeout = TimeSpan.FromSeconds(15) };
    }

    public async Task<LicenseValidationResult> ValidateAsync(string key, CancellationToken ct = default)
    {
        if (string.IsNullOrWhiteSpace(key))
            return new LicenseValidationResult { IsValid = false, Error = "Key is empty" };

        try
        {
            var request = new { key = key.Trim(), organization_id = OrganizationId };
            var response = await _http.PostAsJsonAsync(ValidateUrl, request, ct);

            if (!response.IsSuccessStatusCode)
            {
                var body = await response.Content.ReadAsStringAsync(ct);
                return new LicenseValidationResult
                {
                    IsValid = false,
                    Error = $"Validation failed ({(int)response.StatusCode}): {body}"
                };
            }

            var result = await response.Content.ReadFromJsonAsync<PolarValidateResponse>(ct);
            if (result == null)
                return new LicenseValidationResult { IsValid = false, Error = "Empty response from Polar" };

            var status = result.Status?.ToLowerInvariant();
            return new LicenseValidationResult
            {
                IsValid = status == "granted",
                Status = status ?? "unknown",
                ExpiresAt = result.ExpiresAt,
                Error = status == "granted" ? null : $"License status: {status}"
            };
        }
        catch (TaskCanceledException)
        {
            return new LicenseValidationResult { IsValid = false, Error = "Validation timed out" };
        }
        catch (HttpRequestException ex)
        {
            return new LicenseValidationResult { IsValid = false, Error = $"Network error: {ex.Message}" };
        }
        catch (Exception ex)
        {
            return new LicenseValidationResult { IsValid = false, Error = $"Unexpected error: {ex.Message}" };
        }
    }

    private sealed class PolarValidateResponse
    {
        [JsonPropertyName("status")]
        public string? Status { get; set; }

        [JsonPropertyName("expires_at")]
        public DateTime? ExpiresAt { get; set; }
    }
}

public sealed class LicenseValidationResult
{
    public bool IsValid { get; set; }
    public string? Status { get; set; }
    public DateTime? ExpiresAt { get; set; }
    public string? Error { get; set; }
}