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

namespace FrameworkBLL.VersionSync;

public class SqlWorkbenchVersionClient : ISqlWorkbenchVersionClient
{
    // SqlWorkbench's own control-plane schema (SW.*) lives in the "Gb5System" database — same
    // convention as EntitlementBLL.Onboarding.SqlWorkbenchClient.
    private const string SqlWorkbenchDatabaseName = "Gb5System";

    private readonly IHttpClientFactory _HttpClientFactory;
    private readonly ILogger<SqlWorkbenchVersionClient> _Logger;

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

    public async Task<SwClientVersionRollupDTO?> GetCurrentVersionAsync(int clientDbId, LoginDTO swLogin, CancellationToken ct)
    {
        var client = CreateClient(swLogin);
        var response = await client.GetAsync($"/Provisioning/GetCurrentVersion?ClientDbId={clientDbId}", ct).ConfigureAwait(false);
        var raw = await ReadAndEnsureSuccessAsync(response, "GetCurrentVersion", ct).ConfigureAwait(false);
        return ParseBody<SwClientVersionRollupDTO>(raw);
    }

    public async Task<SwClientDatabaseDTO?> GetClientDatabaseAsync(int clientDbId, LoginDTO swLogin, CancellationToken ct)
    {
        var client = CreateClient(swLogin);
        var response = await client.GetAsync($"/ClientDatabase/GetClientDatabaseById?ClientDbId={clientDbId}", ct).ConfigureAwait(false);
        var raw = await ReadAndEnsureSuccessAsync(response, "GetClientDatabaseById", ct).ConfigureAwait(false);
        return ParseBody<SwClientDatabaseDTO>(raw);
    }

    // ── Helpers ──────────────────────────────────────────────────────────────

    private HttpClient CreateClient(LoginDTO eventLogin)
    {
        var client = _HttpClientFactory.CreateClient("SqlWorkbench");

        // Forward the exact Login that already succeeded moments earlier inside SqlWorkbench's
        // own ChangeRequestBLL.Execute() for this ClientDatabaseId (embedded, unencoded, in the
        // sqlworkbench.changerequest.applied event by EventLogPublish) — this subscriber has no
        // HTTP session/request of its own to build a Login from, and reusing the event's own
        // Login guarantees the TenantId scoping ClientDatabaseDAL.GetById filters on will match.
        // Only DatabaseName is forced, same reasoning as SqlWorkbenchClient.CreateClient.
        var swLogin = new LoginDTO
        {
            ClientId = eventLogin.ClientId,
            UserId = eventLogin.UserId,
            DatabaseName = SqlWorkbenchDatabaseName,
        };

        client.DefaultRequestHeaders.Remove("Login");
        client.DefaultRequestHeaders.Add("Login", JsonSerializer.Serialize(swLogin));
        return client;
    }

    private async Task<string> ReadAndEnsureSuccessAsync(HttpResponseMessage response, string operation, CancellationToken ct)
    {
        var raw = await response.Content.ReadAsStringAsync(ct).ConfigureAwait(false);

        if (!response.IsSuccessStatusCode)
        {
            _Logger.LogError("SqlWorkbench {Operation} returned {StatusCode}: {Body}", operation, response.StatusCode, raw);
            throw new InvalidOperationException($"SqlWorkbench {operation} failed ({(int)response.StatusCode}): {ExtractErrorBody(raw) ?? raw}");
        }

        var errorBody = ExtractErrorBody(raw);
        if (!string.IsNullOrEmpty(errorBody))
        {
            _Logger.LogError("SqlWorkbench {Operation} returned 200 with an ErrorBody: {ErrorBody}", operation, errorBody);
            throw new InvalidOperationException($"SqlWorkbench {operation} failed: {errorBody}");
        }

        return raw;
    }

    private static string? ExtractErrorBody(string rawJson)
    {
        try
        {
            using var doc = JsonDocument.Parse(rawJson);
            if (doc.RootElement.TryGetProperty("ErrorBody", out var err) && err.ValueKind == JsonValueKind.String)
                return err.GetString();
        }
        catch { /* not JSON, or no ErrorBody property — treated as success by the caller */ }
        return null;
    }

    private static T? ParseBody<T>(string rawJson) where T : class
    {
        using var doc = JsonDocument.Parse(rawJson);
        if (!doc.RootElement.TryGetProperty("Body", out var body) || body.ValueKind != JsonValueKind.Object)
            return null;

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