using StellaOps.Integrations.Contracts;
using StellaOps.Integrations.Core;
using System.Net.Http.Headers;
using System.Text.Json;

namespace StellaOps.Integrations.Plugin.Consul;

/// <summary>
/// HashiCorp Consul connector plugin.
/// Supports Consul HTTP API v1 for service discovery and KV configuration.
/// </summary>
public sealed class ConsulConnectorPlugin : IIntegrationConnectorPlugin
{
    private readonly TimeProvider _timeProvider;

    public ConsulConnectorPlugin()
        : this(TimeProvider.System)
    {
    }

    public ConsulConnectorPlugin(TimeProvider? timeProvider = null)
    {
        _timeProvider = timeProvider ?? TimeProvider.System;
    }

    public string Name => "consul";

    public IntegrationType Type => IntegrationType.SecretsManager;

    public IntegrationProvider Provider => IntegrationProvider.Consul;

    public bool IsAvailable(IServiceProvider services) => true;

    public async Task<TestConnectionResult> TestConnectionAsync(IntegrationConfig config, CancellationToken cancellationToken = default)
    {
        var startTime = _timeProvider.GetUtcNow();

        using var client = CreateHttpClient(config);

        try
        {
            // Call Consul leader status endpoint
            var response = await client.GetAsync("/v1/status/leader", cancellationToken);
            var duration = _timeProvider.GetUtcNow() - startTime;

            if (response.IsSuccessStatusCode)
            {
                var content = await response.Content.ReadAsStringAsync(cancellationToken);

                // Consul returns a quoted string like "127.0.0.1:8300" when healthy
                var isHealthy = !string.IsNullOrWhiteSpace(content) && content.StartsWith('"') && content.Length > 2;
                var leaderAddress = content.Trim('"');

                return new TestConnectionResult(
                    Success: isHealthy,
                    Message: isHealthy ? "Consul connection successful" : "Consul returned empty leader",
                    Details: new Dictionary<string, string>
                    {
                        ["endpoint"] = config.Endpoint,
                        ["leader"] = leaderAddress
                    },
                    Duration: duration);
            }

            return new TestConnectionResult(
                Success: false,
                Message: $"Consul returned {response.StatusCode}",
                Details: new Dictionary<string, string>
                {
                    ["endpoint"] = config.Endpoint,
                    ["statusCode"] = ((int)response.StatusCode).ToString()
                },
                Duration: duration);
        }
        catch (Exception ex)
        {
            var duration = _timeProvider.GetUtcNow() - startTime;
            return new TestConnectionResult(
                Success: false,
                Message: $"Connection failed: {ex.Message}",
                Details: new Dictionary<string, string>
                {
                    ["endpoint"] = config.Endpoint,
                    ["error"] = ex.GetType().Name
                },
                Duration: duration);
        }
    }

    public async Task<HealthCheckResult> CheckHealthAsync(IntegrationConfig config, CancellationToken cancellationToken = default)
    {
        var startTime = _timeProvider.GetUtcNow();

        using var client = CreateHttpClient(config);

        try
        {
            var response = await client.GetAsync("/v1/agent/self", cancellationToken);
            var duration = _timeProvider.GetUtcNow() - startTime;

            if (response.IsSuccessStatusCode)
            {
                var content = await response.Content.ReadAsStringAsync(cancellationToken);
                var agentSelf = JsonSerializer.Deserialize<ConsulAgentSelfResponse>(content, JsonOptions);

                return new HealthCheckResult(
                    Status: HealthStatus.Healthy,
                    Message: $"Consul agent healthy: {agentSelf?.Config?.NodeName ?? "unknown"}",
                    Details: new Dictionary<string, string>
                    {
                        ["nodeName"] = agentSelf?.Config?.NodeName ?? "unknown",
                        ["datacenter"] = agentSelf?.Config?.Datacenter ?? "unknown"
                    },
                    CheckedAt: _timeProvider.GetUtcNow(),
                    Duration: duration);
            }

            return new HealthCheckResult(
                Status: HealthStatus.Unhealthy,
                Message: $"Consul returned {response.StatusCode}",
                Details: new Dictionary<string, string> { ["statusCode"] = ((int)response.StatusCode).ToString() },
                CheckedAt: _timeProvider.GetUtcNow(),
                Duration: duration);
        }
        catch (Exception ex)
        {
            var duration = _timeProvider.GetUtcNow() - startTime;
            return new HealthCheckResult(
                Status: HealthStatus.Unhealthy,
                Message: $"Health check failed: {ex.Message}",
                Details: new Dictionary<string, string> { ["error"] = ex.GetType().Name },
                CheckedAt: _timeProvider.GetUtcNow(),
                Duration: duration);
        }
    }

    private static HttpClient CreateHttpClient(IntegrationConfig config)
    {
        var client = new HttpClient
        {
            BaseAddress = new Uri(config.Endpoint.TrimEnd('/')),
            Timeout = TimeSpan.FromSeconds(30)
        };

        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

        // Add Consul ACL token if secret is provided
        if (!string.IsNullOrEmpty(config.ResolvedSecret))
        {
            client.DefaultRequestHeaders.Add("X-Consul-Token", config.ResolvedSecret);
        }

        return client;
    }

    private static readonly JsonSerializerOptions JsonOptions = new()
    {
        PropertyNameCaseInsensitive = true
    };

    // -- Consul API DTOs ────────────────────────────────────────────

    private sealed class ConsulAgentSelfResponse
    {
        public ConsulConfig? Config { get; set; }
        public ConsulMember? Member { get; set; }
    }

    private sealed class ConsulConfig
    {
        public string? NodeName { get; set; }
        public string? Datacenter { get; set; }
    }

    private sealed class ConsulMember
    {
        public int Status { get; set; }
    }
}