using System.Net.Http.Json;
using System.Text.Json;
using GB5Shared.DTO.Framework.Login;
using Microsoft.Extensions.Logging;

namespace SwBLL.Integration;

/// <summary>Mirrors EntitlementBLL.Onboarding.SqlWorkbenchClient's exact shape (IHttpClientFactory,
/// a named client, JSON GET, Login-header convention) for the reverse direction — SqlWorkbench
/// calling INTO Entitlement (tracker §40) instead of Entitlement calling into SqlWorkbench.</summary>
public class EntitlementSubscriptionClient : IEntitlementSubscriptionClient
{
    private readonly IHttpClientFactory _HttpClientFactory;
    private readonly ILogger<EntitlementSubscriptionClient> _Logger;

    public EntitlementSubscriptionClient(IHttpClientFactory httpClientFactory, ILogger<EntitlementSubscriptionClient> logger)
    {
        _HttpClientFactory = httpClientFactory;
        _Logger            = logger;
    }

    public async Task<EntitlementSnapshotDTO?> GetSnapshotAsync(int clientId, LoginDTO swLogin, CancellationToken ct)
    {
        var client = _HttpClientFactory.CreateClient("Entitlement");

        // Only ClientId carries meaning for this call — DatabaseName is Entitlement's own
        // concern to resolve server-side, not something SqlWorkbench should dictate (unlike the
        // reverse direction, where Entitlement must explicitly override DatabaseName to
        // "Gb5System" since it knows SW's schema lives there — SqlWorkbench has no equivalent
        // fixed knowledge of which physical database backs Entitlement in a given deployment).
        var login = new LoginDTO { ClientId = swLogin.ClientId, UserId = swLogin.UserId };
        client.DefaultRequestHeaders.Remove("Login");
        client.DefaultRequestHeaders.Add("Login", JsonSerializer.Serialize(login));

        HttpResponseMessage response;
        try
        {
            response = await client.GetAsync($"/lic/Subscription.svc/GetClientEntitlementSnapshot?ClientId={clientId}", ct)
                .ConfigureAwait(false);
        }
        catch (HttpRequestException ex)
        {
            _Logger.LogError(ex, "Entitlement GetClientEntitlementSnapshot call failed for ClientId {ClientId}.", clientId);
            throw new InvalidOperationException($"Could not reach Entitlement to resolve entitlement snapshot for ClientId {clientId}.", ex);
        }

        var raw = await response.Content.ReadAsStringAsync(ct).ConfigureAwait(false);
        if (!response.IsSuccessStatusCode)
        {
            _Logger.LogError("Entitlement GetClientEntitlementSnapshot returned {StatusCode} for ClientId {ClientId}: {Body}",
                response.StatusCode, clientId, raw);
            throw new InvalidOperationException($"Entitlement GetClientEntitlementSnapshot failed ({(int)response.StatusCode}) for ClientId {clientId}.");
        }

        using var doc = JsonDocument.Parse(raw);
        if (!doc.RootElement.TryGetProperty("Body", out var body) || body.ValueKind != JsonValueKind.Object)
            return null; // Entitlement has nothing for this client — caller treats as "cannot determine"

        return body.Deserialize<EntitlementSnapshotDTO>(new JsonSerializerOptions { PropertyNameCaseInsensitive = true });
    }
}