using ControlPlane.Core.Models;
using ControlPlane.Core.Services;
using Docker.DotNet;
using Docker.DotNet.Models;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;

namespace ControlPlane.Api.Services;

/// <summary>
/// Orchestrates a release: finds all managed tenant containers matching the target
/// environment, removes each one, and restarts it from the latest clarity-server image.
/// Does NOT re-run Keycloak/Vault/DB steps — the container env vars are preserved from
/// the original provisioning and re-injected from the XML registry.
/// </summary>
public class ReleaseService(
    IConfiguration config,
    TenantRegistryService registry,
    BuildHistoryService history,
    PromotionService promotions,
    ILogger<ReleaseService> logger)
{
    private static readonly SemaphoreSlim _lock = new(1, 1);

    public bool IsReleasing => _lock.CurrentCount == 0;
    public string ImageName  => config["Docker:ClarityServerImage"] ?? "clarity-server:latest";

    /// <summary>
    /// Runs a release for the given environment and streams status lines to <paramref name="onLine"/>.
    /// </summary>
    public async Task<ReleaseRecord> ReleaseAsync(
        string targetEnv,
        Action<string> onLine,
        CancellationToken ct)
    {
        if (!await _lock.WaitAsync(TimeSpan.Zero, ct))
        {
            onLine("⚠️  A release is already in progress.");
            var blocked = new ReleaseRecord
            {
                Environment = targetEnv,
                ImageName   = ImageName,
                Status      = ReleaseStatus.Failed,
                FinishedAt  = DateTimeOffset.UtcNow,
            };
            blocked.Tenants.Add(new TenantReleaseResult
            {
                Subdomain = "*", ContainerName = "*",
                Success = false, Error = "Release already in progress.",
            });
            return blocked;
        }

        // Resolve the Clarity branch for this environment and stamp the HEAD SHA
        // before creating the record so we capture "what was deployed" accurately.
        var branch    = targetEnv switch { "fdev" => "develop", "staging" => "staging", "uat" => "uat", _ => "main" };
        var currentSha = promotions.GetBranchTipSha("Clarity", branch);

        var record = await history.CreateReleaseAsync(targetEnv, ImageName, currentSha);

        try
        {
            onLine($"▶ Release to [{targetEnv}] using {ImageName}");
            onLine("──────────────────────────────────────");

            var socketUri = config["Docker:Socket"] ?? "npipe://./pipe/docker_engine";
            using var docker = new DockerClientConfiguration(new Uri(socketUri)).CreateClient();

            // Find all managed tenant containers for this environment
            var filterEnv = targetEnv == "all"
                ? new Dictionary<string, IDictionary<string, bool>>
                  {
                      ["label"] = new Dictionary<string, bool> { ["clarity.managed=true"] = true },
                  }
                : new Dictionary<string, IDictionary<string, bool>>
                  {
                      ["label"] = new Dictionary<string, bool>
                      {
                          ["clarity.managed=true"]              = true,
                          [$"clarity.env={targetEnv}"]         = true,
                      },
                  };

            var containers = await docker.Containers.ListContainersAsync(
                new ContainersListParameters { All = true, Filters = filterEnv }, ct);

            if (containers.Count == 0)
            {
                onLine($"  No managed containers found for environment [{targetEnv}].");
                record.Status     = ReleaseStatus.Succeeded;
                record.FinishedAt = DateTimeOffset.UtcNow;
                await history.UpdateReleaseAsync(record);
                return record;
            }

            onLine($"  Found {containers.Count} container(s) to redeploy.");
            onLine("");

            int succeeded = 0, failed = 0;

            foreach (var container in containers)
            {
                var name = container.Names.FirstOrDefault()?.TrimStart('/') ?? container.ID[..12];
                var tenantResult = new TenantReleaseResult
                {
                    ContainerName = name,
                    Subdomain     = container.Labels.TryGetValue("clarity.subdomain", out var sub) ? sub : name,
                };
                record.Tenants.Add(tenantResult);

                try
                {
                    onLine($"  → {name}");

                    // Read env vars from existing container — preserve Keycloak/Vault/DB config
                    var inspect = await docker.Containers.InspectContainerAsync(container.ID, ct);
                    var env     = inspect.Config.Env;
                    var labels  = inspect.Config.Labels;
                    var network = inspect.HostConfig.NetworkMode;

                    // Stop and remove old container
                    onLine($"    Stopping...");
                    try
                    {
                        await docker.Containers.StopContainerAsync(
                            container.ID, new ContainerStopParameters { WaitBeforeKillSeconds = 8 }, ct);
                        await docker.Containers.RemoveContainerAsync(
                            container.ID, new ContainerRemoveParameters { Force = true }, ct);
                    }
                    catch (Exception ex)
                    {
                        logger.LogWarning(ex, "Stop/remove failed for {Name}, forcing removal.", name);
                        await docker.Containers.RemoveContainerAsync(
                            container.ID, new ContainerRemoveParameters { Force = true }, ct);
                    }

                    // Create fresh container from latest image, preserving all env vars and labels
                    onLine($"    Creating from {ImageName}...");
                    var created = await docker.Containers.CreateContainerAsync(
                        new CreateContainerParameters
                        {
                            Name   = name,
                            Image  = ImageName,
                            Env    = env,
                            Labels = labels,
                            HostConfig = new HostConfig
                            {
                                NetworkMode   = network,
                                RestartPolicy = new RestartPolicy { Name = RestartPolicyKind.UnlessStopped },
                            },
                        }, ct);

                    // Start it
                    var started = await docker.Containers.StartContainerAsync(created.ID, null, ct);
                    if (!started) throw new InvalidOperationException("Docker returned false for start.");

                    onLine($"    ✔ {name} redeployed.");
                    tenantResult.Success = true;
                    succeeded++;
                }
                catch (Exception ex)
                {
                    logger.LogError(ex, "Failed to redeploy {Name}.", name);
                    onLine($"    ✖ {name} failed: {ex.Message}");
                    tenantResult.Success = false;
                    tenantResult.Error   = ex.Message;
                    failed++;
                }

                await history.UpdateReleaseAsync(record);
            }

            record.Status     = failed == 0 ? ReleaseStatus.Succeeded
                              : succeeded == 0 ? ReleaseStatus.Failed
                              : ReleaseStatus.PartialFailure;
            record.FinishedAt = DateTimeOffset.UtcNow;

            onLine("");
            onLine("──────────────────────────────────────");
            onLine($"{(record.Status == ReleaseStatus.Succeeded ? "✔" : "⚠")} Release complete — {succeeded} succeeded, {failed} failed.");
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "Release to [{Env}] threw an unhandled exception.", targetEnv);
            record.Status     = ReleaseStatus.Failed;
            record.FinishedAt = DateTimeOffset.UtcNow;
            onLine($"✖ Release aborted: {ex.Message}");
        }
        finally
        {
            // Stamp the exact OPC ticket numbers introduced by this release:
            // diff from previous release's SHA to this release's SHA on the Clarity branch.
            try
            {
                var prev = await history.GetLastSuccessfulReleaseForEnvAsync(targetEnv);
                // Exclude the current (in-flight) record — it's not succeeded yet
                var prevSha = prev?.Id == record.Id ? null : prev?.CommitSha;
                if (currentSha is not null)
                    record.OpcNumbers = await promotions.ExtractOpcNumbersDeltaAsync("Clarity", currentSha, prevSha, ct);
            }
            catch { /* git not configured — continue without OPC stamp */ }

            await history.UpdateReleaseAsync(record);
            _lock.Release();
        }

        return record;
    }
}