using System.Diagnostics;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using MySqlConnector;
using OTSSignsOrchestrator.Core.Configuration;
using OTSSignsOrchestrator.Core.Models.DTOs;
using OTSSignsOrchestrator.Core.Models.Entities;
using OTSSignsOrchestrator.Core.Services;
using ServiceLogEntry = OTSSignsOrchestrator.Core.Models.DTOs.ServiceLogEntry;

namespace OTSSignsOrchestrator.Desktop.Services;

/// <summary>
/// Docker CLI service that executes docker commands on a remote host over SSH.
/// Requires an SshHost to be set before use via SetHost().
/// </summary>
public class SshDockerCliService : IDockerCliService
{
    private readonly SshConnectionService _ssh;
    private readonly DockerOptions _options;
    private readonly ILogger<SshDockerCliService> _logger;
    private SshHost? _currentHost;

    public SshDockerCliService(
        SshConnectionService ssh,
        IOptions<DockerOptions> options,
        ILogger<SshDockerCliService> logger)
    {
        _ssh = ssh;
        _options = options.Value;
        _logger = logger;
    }

    /// <summary>
    /// Set the SSH host to use for Docker commands.
    /// </summary>
    public void SetHost(SshHost host)
    {
        _currentHost = host;
    }

    public SshHost? CurrentHost => _currentHost;

    public async Task<DeploymentResultDto> DeployStackAsync(string stackName, string composeYaml, bool resolveImage = false)
    {
        EnsureHost();
        var sw = Stopwatch.StartNew();

        var args = "docker stack deploy --compose-file -";
        if (resolveImage)
            args += " --resolve-image changed";
        args += $" {stackName}";

        _logger.LogInformation("Deploying stack via SSH: {StackName} on {Host}", stackName, _currentHost!.Label);

        var (exitCode, stdout, stderr) = await _ssh.RunCommandWithStdinAsync(_currentHost, args, composeYaml);
        sw.Stop();

        var result = new DeploymentResultDto
        {
            StackName = stackName,
            Success = exitCode == 0,
            ExitCode = exitCode,
            Output = stdout,
            ErrorMessage = stderr,
            Message = exitCode == 0 ? "Success" : "Failed",
            DurationMs = sw.ElapsedMilliseconds
        };

        if (result.Success)
            _logger.LogInformation("Stack deployed via SSH: {StackName} | duration={DurationMs}ms", stackName, result.DurationMs);
        else
            _logger.LogError("Stack deploy failed via SSH: {StackName} | error={Error}", stackName, result.ErrorMessage);

        return result;
    }

    public async Task<DeploymentResultDto> RemoveStackAsync(string stackName)
    {
        EnsureHost();
        var sw = Stopwatch.StartNew();

        _logger.LogInformation("Removing stack via SSH: {StackName} on {Host}", stackName, _currentHost!.Label);

        var (exitCode, stdout, stderr) = await _ssh.RunCommandAsync(_currentHost, $"docker stack rm {stackName}");
        sw.Stop();

        var result = new DeploymentResultDto
        {
            StackName = stackName,
            Success = exitCode == 0,
            ExitCode = exitCode,
            Output = stdout,
            ErrorMessage = stderr,
            Message = exitCode == 0 ? "Success" : "Failed",
            DurationMs = sw.ElapsedMilliseconds
        };

        if (result.Success)
            _logger.LogInformation("Stack removed via SSH: {StackName}", stackName);
        else
            _logger.LogError("Stack remove failed via SSH: {StackName} | error={Error}", stackName, result.ErrorMessage);

        return result;
    }

    public async Task<List<StackInfo>> ListStacksAsync()
    {
        EnsureHost();

        var (exitCode, stdout, _) = await _ssh.RunCommandAsync(
            _currentHost!, "docker stack ls --format '{{.Name}}\\t{{.Services}}'");

        if (exitCode != 0 || string.IsNullOrWhiteSpace(stdout))
            return new List<StackInfo>();

        return stdout
            .Split('\n', StringSplitOptions.RemoveEmptyEntries)
            .Select(line =>
            {
                var parts = line.Split('\t', 2);
                return new StackInfo
                {
                    Name = parts[0].Trim(),
                    ServiceCount = parts.Length > 1 && int.TryParse(parts[1].Trim(), out var c) ? c : 0
                };
            })
            .ToList();
    }

    public async Task<List<ServiceInfo>> InspectStackServicesAsync(string stackName)
    {
        EnsureHost();

        var (exitCode, stdout, _) = await _ssh.RunCommandAsync(
            _currentHost!, $"docker stack services {stackName} --format '{{{{.Name}}}}\\t{{{{.Image}}}}\\t{{{{.Replicas}}}}'");

        if (exitCode != 0 || string.IsNullOrWhiteSpace(stdout))
            return new List<ServiceInfo>();

        return stdout
            .Split('\n', StringSplitOptions.RemoveEmptyEntries)
            .Select(line =>
            {
                var parts = line.Split('\t', 3);
                return new ServiceInfo
                {
                    Name = parts.Length > 0 ? parts[0].Trim() : "",
                    Image = parts.Length > 1 ? parts[1].Trim() : "",
                    Replicas = parts.Length > 2 ? parts[2].Trim() : ""
                };
            })
            .ToList();
    }

    public async Task<bool> EnsureDirectoryAsync(string path)
    {
        EnsureHost();
        var (exitCode, _, stderr) = await _ssh.RunCommandAsync(_currentHost!, $"mkdir -p {path}");
        if (exitCode != 0)
            _logger.LogWarning("Failed to create directory {Path} on {Host}: {Error}", path, _currentHost!.Label, stderr);
        else
            _logger.LogInformation("Ensured directory exists on {Host}: {Path}", _currentHost!.Label, path);
        return exitCode == 0;
    }

    public async Task<bool> EnsureNfsFoldersAsync(
        string nfsServer,
        string nfsExport,
        IEnumerable<string> folderNames,
        string? nfsExportFolder = null)
    {
        EnsureHost();
        var exportPath = (nfsExport ?? string.Empty).Trim('/');
        var subFolder = (nfsExportFolder ?? string.Empty).Trim('/');

        // Build the sub-path beneath the mount point where volume folders will be created
        var subPath = string.IsNullOrEmpty(subFolder) ? string.Empty : $"/{subFolder}";

        // Build mkdir targets relative to the temporary mount point
        var folderList = folderNames.Select(f => $"\"$MNT{subPath}/{f}\"").ToList();
        var mkdirTargets = string.Join(" ", folderList);

        // Single SSH command: create temp dir, mount NFS, mkdir -p all folders, unmount, cleanup
        // Use addr= to pin the server IP — avoids "Server address does not match proto= option"
        // errors when the hostname resolves to IPv6 but proto=tcp implies IPv4.
        var script = $"""
            set -e
            MNT=$(mktemp -d)
            sudo mount -t nfs -o addr={nfsServer},nfsvers=4,proto=tcp,soft,timeo=50,retrans=2 {nfsServer}:/{exportPath} "$MNT"
            sudo mkdir -p {mkdirTargets}
            sudo umount "$MNT"
            rmdir "$MNT"
            """;

        _logger.LogInformation(
            "Mounting NFS export {Server}:/{Export} on Docker host {Host} to create {Count} folders",
            nfsServer, exportPath, _currentHost!.Label, folderList.Count);

        var (exitCode, stdout, stderr) = await _ssh.RunCommandAsync(_currentHost!, script, TimeSpan.FromSeconds(30));

        if (exitCode == 0)
        {
            _logger.LogInformation(
                "NFS export folders ensured via mount on {Host}: {Server}:/{Export}{Sub} ({Count} folders)",
                _currentHost.Label, nfsServer, exportPath, subPath, folderList.Count);
        }
        else
        {
            _logger.LogWarning(
                "Failed to create NFS export folders on {Host}: {Error}",
                _currentHost.Label, (stderr ?? stdout ?? "unknown error").Trim());
            return false;
        }

        return true;
    }

    public async Task<(bool Success, string? Error)> EnsureNfsFoldersWithErrorAsync(
        string nfsServer,
        string nfsExport,
        IEnumerable<string> folderNames,
        string? nfsExportFolder = null)
    {
        EnsureHost();
        var exportPath = (nfsExport ?? string.Empty).Trim('/');
        var subFolder = (nfsExportFolder ?? string.Empty).Trim('/');
        var subPath = string.IsNullOrEmpty(subFolder) ? string.Empty : $"/{subFolder}";
        var folderList = folderNames.Select(f => $"\"$MNT{subPath}/{f}\"").ToList();
        var mkdirTargets = string.Join(" ", folderList);

        var script = $"""
            set -e
            MNT=$(mktemp -d)
            sudo mount -t nfs -o addr={nfsServer},nfsvers=4,proto=tcp,soft,timeo=50,retrans=2 {nfsServer}:/{exportPath} "$MNT"
            sudo mkdir -p {mkdirTargets}
            sudo umount "$MNT"
            rmdir "$MNT"
            """;

        _logger.LogInformation(
            "Mounting NFS export {Server}:/{Export} on Docker host {Host} to create {Count} folders",
            nfsServer, exportPath, _currentHost!.Label, folderList.Count);

        var (exitCode, stdout, stderr) = await _ssh.RunCommandAsync(_currentHost!, script, TimeSpan.FromSeconds(30));

        if (exitCode == 0)
        {
            _logger.LogInformation(
                "NFS export folders ensured via mount on {Host}: {Server}:/{Export}{Sub} ({Count} folders)",
                _currentHost.Label, nfsServer, exportPath, subPath, folderList.Count);
            return (true, null);
        }

        var error = (stderr ?? stdout ?? "unknown error").Trim();
        _logger.LogWarning(
            "Failed to create NFS export folders on {Host}: {Error}",
            _currentHost.Label, error);
        return (false, error);
    }

    public async Task<bool> ForceUpdateServiceAsync(string serviceName)
    {
        EnsureHost();
        _logger.LogInformation("Force-updating service {ServiceName} on {Host}", serviceName, _currentHost!.Label);
        var (exitCode, _, stderr) = await _ssh.RunCommandAsync(_currentHost!, $"docker service update --force {serviceName}");
        if (exitCode != 0)
            _logger.LogWarning("Force-update failed for {ServiceName}: {Error}", serviceName, stderr);
        return exitCode == 0;
    }

    public async Task<(MySqlConnection Connection, IDisposable Tunnel)> OpenMySqlConnectionAsync(
        string mysqlHost, int port,
        string adminUser, string adminPassword)
    {
        EnsureHost();
        _logger.LogInformation(
            "Opening tunnelled MySQL connection to {MysqlHost}:{Port} via SSH",
            mysqlHost, port);

        var tunnel = _ssh.OpenForwardedPort(_currentHost!, mysqlHost, (uint)port);
        var localPort = (int)tunnel.BoundPort;

        var csb = new MySqlConnectionStringBuilder
        {
            Server            = "127.0.0.1",
            Port              = (uint)localPort,
            UserID            = adminUser,
            Password          = adminPassword,
            ConnectionTimeout = 15,
            SslMode           = MySqlSslMode.Disabled,
        };

        var connection = new MySqlConnection(csb.ConnectionString);
        try
        {
            await connection.OpenAsync();
            return (connection, tunnel);
        }
        catch
        {
            await connection.DisposeAsync();
            tunnel.Dispose();
            throw;
        }
    }

    public async Task<(bool Success, string Error)> AlterMySqlUserPasswordAsync(
        string mysqlHost, int port,
        string adminUser, string adminPassword,
        string targetUser, string newPassword)
    {
        _logger.LogInformation(
            "Altering MySQL password for user {User} on {MysqlHost}:{Port} via SSH tunnel",
            targetUser, mysqlHost, port);

        try
        {
            var (connection, tunnel) = await OpenMySqlConnectionAsync(mysqlHost, port, adminUser, adminPassword);
            await using (connection)
            using (tunnel)
            {
                var escapedUser = targetUser.Replace("'", "''");
                await using var cmd = connection.CreateCommand();
                cmd.CommandText = $"ALTER USER '{escapedUser}'@'%' IDENTIFIED BY @pwd";
                cmd.Parameters.AddWithValue("@pwd", newPassword);
                await cmd.ExecuteNonQueryAsync();
            }

            _logger.LogInformation("MySQL password updated for user {User} via SSH tunnel", targetUser);
            return (true, string.Empty);
        }
        catch (MySqlException ex)
        {
            _logger.LogError(ex, "MySQL ALTER USER failed via SSH tunnel for user {User}", targetUser);
            return (false, ex.Message);
        }
    }

    public async Task<bool> ServiceSwapSecretAsync(string serviceName, string oldSecretName, string newSecretName, string? targetAlias = null)
    {
        EnsureHost();
        var target = targetAlias ?? oldSecretName;
        var cmd = $"docker service update --secret-rm {oldSecretName} --secret-add \"source={newSecretName},target={target}\" {serviceName}";
        _logger.LogInformation(
            "Swapping secret on {ServiceName}: {OldSecret} → {NewSecret} (target={Target})",
            serviceName, oldSecretName, newSecretName, target);
        var (exitCode, _, stderr) = await _ssh.RunCommandAsync(_currentHost!, cmd);
        if (exitCode != 0)
            _logger.LogError("Secret swap failed for {ServiceName}: {Error}", serviceName, stderr);
        return exitCode == 0;
    }

    public async Task<List<NodeInfo>> ListNodesAsync()
    {
        EnsureHost();

        _logger.LogInformation("Listing swarm nodes via SSH on {Host}", _currentHost!.Label);

        // Use docker node inspect on all nodes to get IP addresses (Status.Addr)
        // that are not available from 'docker node ls'.
        // First, get all node IDs.
        var (lsExit, lsOut, lsErr) = await _ssh.RunCommandAsync(
            _currentHost!, "docker node ls --format '{{.ID}}'");

        if (lsExit != 0)
        {
            var msg = (lsErr ?? lsOut ?? "unknown error").Trim();
            _logger.LogWarning("docker node ls failed on {Host} (exit {Code}): {Error}",
                _currentHost.Label, lsExit, msg);
            throw new InvalidOperationException(
                $"Failed to list swarm nodes on {_currentHost.Label}: {msg}");
        }

        if (string.IsNullOrWhiteSpace(lsOut))
            return new List<NodeInfo>();

        var nodeIds = lsOut.Split('\n', StringSplitOptions.RemoveEmptyEntries)
            .Select(id => id.Trim())
            .Where(id => !string.IsNullOrEmpty(id))
            .ToList();

        if (nodeIds.Count == 0)
            return new List<NodeInfo>();

        // Inspect all nodes in a single call to get full details including IP address
        var ids = string.Join(" ", nodeIds);
        var format = "'{{.ID}}\t{{.Description.Hostname}}\t{{.Status.State}}\t{{.Spec.Availability}}\t{{.ManagerStatus.Addr}}\t{{.Status.Addr}}\t{{.Description.Engine.EngineVersion}}\t{{.Spec.Role}}'";
        var (exitCode, stdout, stderr) = await _ssh.RunCommandAsync(
            _currentHost!, $"docker node inspect --format {format} {ids}");

        if (exitCode != 0)
        {
            var msg = (stderr ?? stdout ?? "unknown error").Trim();
            _logger.LogWarning("docker node inspect failed on {Host} (exit {Code}): {Error}",
                _currentHost.Label, exitCode, msg);
            throw new InvalidOperationException(
                $"Failed to inspect swarm nodes on {_currentHost.Label}: {msg}");
        }

        if (string.IsNullOrWhiteSpace(stdout))
            return new List<NodeInfo>();

        return stdout
            .Split('\n', StringSplitOptions.RemoveEmptyEntries)
            .Select(line =>
            {
                var parts = line.Split('\t', 8);
                // ManagerStatus.Addr includes port (e.g. "10.0.0.1:2377"); Status.Addr is just the IP.
                // Prefer Status.Addr; fall back to ManagerStatus.Addr (strip port) if Status.Addr is empty/template-error.
                var statusAddr = parts.Length > 5 ? parts[5].Trim() : "";
                var managerAddr = parts.Length > 4 ? parts[4].Trim() : "";
                var ip = statusAddr;
                if (string.IsNullOrEmpty(ip) || ip.StartsWith("<") || ip.StartsWith("{"))
                {
                    // managerAddr may be "10.0.0.1:2377"
                    ip = managerAddr.Contains(':') ? managerAddr[..managerAddr.LastIndexOf(':')] : managerAddr;
                }
                // Clean up template rendering artefacts like "<no value>"
                if (ip.StartsWith("<") || ip.StartsWith("{"))
                    ip = "";

                var role = parts.Length > 7 ? parts[7].Trim() : "";
                var managerStatus = "";
                if (string.Equals(role, "manager", StringComparison.OrdinalIgnoreCase))
                {
                    // Determine if this is the leader by checking if ManagerStatus.Addr is non-empty
                    managerStatus = !string.IsNullOrEmpty(managerAddr) && !managerAddr.StartsWith("<") ? "Reachable" : "";
                }

                return new NodeInfo
                {
                    Id = parts.Length > 0 ? parts[0].Trim() : "",
                    Hostname = parts.Length > 1 ? parts[1].Trim() : "",
                    Status = parts.Length > 2 ? parts[2].Trim() : "",
                    Availability = parts.Length > 3 ? parts[3].Trim() : "",
                    ManagerStatus = managerStatus,
                    IpAddress = ip,
                    EngineVersion = parts.Length > 6 ? parts[6].Trim() : ""
                };
            })
            .ToList();
    }

    public async Task<List<ServiceLogEntry>> GetServiceLogsAsync(string stackName, string? serviceName = null, int tailLines = 200)
    {
        EnsureHost();

        // Determine which services to fetch logs for
        List<string> serviceNames;
        if (!string.IsNullOrEmpty(serviceName))
        {
            serviceNames = new List<string> { serviceName };
        }
        else
        {
            var services = await InspectStackServicesAsync(stackName);
            serviceNames = services.Select(s => s.Name).ToList();
        }

        var allEntries = new List<ServiceLogEntry>();
        foreach (var svcName in serviceNames)
        {
            try
            {
                var cmd = $"docker service logs --timestamps --no-trunc --tail {tailLines} {svcName} 2>&1";
                var (exitCode, stdout, _) = await _ssh.RunCommandAsync(_currentHost!, cmd, TimeSpan.FromSeconds(15));

                if (exitCode != 0 || string.IsNullOrWhiteSpace(stdout))
                {
                    _logger.LogDebug("No logs returned for service {Service} (exit={ExitCode})", svcName, exitCode);
                    continue;
                }

                // Parse each line. Docker service logs format with --timestamps:
                //   <timestamp> <service>.<replica>.<taskid>@<node>    | <message>
                // or sometimes just:
                //   <timestamp> <service>.<replica>.<taskid>    <message>
                foreach (var line in stdout.Split('\n', StringSplitOptions.RemoveEmptyEntries))
                {
                    var entry = ParseLogLine(line, svcName, stackName);
                    if (entry != null)
                        allEntries.Add(entry);
                }
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "Failed to fetch logs for service {Service}", svcName);
            }
        }

        return allEntries.OrderBy(e => e.Timestamp).ToList();
    }

    /// <summary>
    /// Parses a single line from <c>docker service logs --timestamps</c> output.
    /// </summary>
    private static ServiceLogEntry? ParseLogLine(string line, string serviceName, string stackName)
    {
        if (string.IsNullOrWhiteSpace(line))
            return null;

        // Format: "2026-02-25T14:30:45.123456789Z service.replica.taskid@node    | message"
        // The timestamp is always the first space-delimited token when --timestamps is used.
        var firstSpace = line.IndexOf(' ');
        if (firstSpace <= 0)
            return new ServiceLogEntry
            {
                Timestamp = DateTimeOffset.UtcNow,
                Source = serviceName,
                ServiceName = StripStackPrefix(serviceName, stackName),
                Message = line
            };

        var timestampStr = line[..firstSpace];
        var rest = line[(firstSpace + 1)..].TrimStart();

        // Try to parse the timestamp
        if (!DateTimeOffset.TryParse(timestampStr, out var timestamp))
        {
            // If timestamp parsing fails, treat the whole line as the message
            return new ServiceLogEntry
            {
                Timestamp = DateTimeOffset.UtcNow,
                Source = serviceName,
                ServiceName = StripStackPrefix(serviceName, stackName),
                Message = line
            };
        }

        // Split source and message on the pipe separator
        var source = serviceName;
        var message = rest;
        var pipeIndex = rest.IndexOf('|');
        if (pipeIndex >= 0)
        {
            source = rest[..pipeIndex].Trim();
            message = rest[(pipeIndex + 1)..].TrimStart();
        }

        return new ServiceLogEntry
        {
            Timestamp = timestamp,
            Source = source,
            ServiceName = StripStackPrefix(serviceName, stackName),
            Message = message
        };
    }

    /// <summary>
    /// Strips the stack name prefix from a fully-qualified service name.
    /// e.g. "acm-cms-stack_acm-web" → "acm-web"
    /// </summary>
    private static string StripStackPrefix(string serviceName, string stackName)
    {
        var prefix = stackName + "_";
        return serviceName.StartsWith(prefix) ? serviceName[prefix.Length..] : serviceName;
    }

    private void EnsureHost()
    {
        if (_currentHost == null)
            throw new InvalidOperationException("No SSH host configured. Call SetHost() before using Docker commands.");
    }

    public async Task<bool> RemoveStackVolumesAsync(string stackName)
    {
        EnsureHost();

        // ── 1. Remove the stack first so containers release the volumes ─────
        _logger.LogInformation("Removing stack {StackName} before volume cleanup", stackName);
        var (rmExit, _, rmErr) = await _ssh.RunCommandAsync(_currentHost!,
            $"docker stack rm {stackName} 2>&1 || true");
        if (rmExit != 0)
            _logger.LogWarning("Stack rm returned non-zero for {StackName}: {Err}", stackName, rmErr);

        // Give Swarm a moment to tear down containers on all nodes
        await Task.Delay(5000);

        // ── 2. Clean volumes on the local (manager) node ────────────────────
        var localCmd = $"docker volume ls --filter \"name={stackName}_\" -q | xargs -r docker volume rm 2>&1 || true";
        var (_, localOut, _) = await _ssh.RunCommandAsync(_currentHost!, localCmd);
        if (!string.IsNullOrEmpty(localOut?.Trim()))
            _logger.LogInformation("Volume cleanup (manager): {Output}", localOut!.Trim());

        // ── 3. Clean volumes on ALL swarm nodes via a temporary global service ──
        // This deploys a short-lived container on every node that mounts the Docker
        // socket and removes matching volumes. This handles worker nodes that the
        // orchestrator has no direct SSH access to.
        var cleanupSvcName = $"vol-cleanup-{stackName}".Replace("_", "-");

        // Remove leftover cleanup service from a previous run (if any)
        await _ssh.RunCommandAsync(_currentHost!,
            $"docker service rm {cleanupSvcName} 2>/dev/null || true");

        var createCmd = string.Join(" ",
            "docker service create",
            "--detach",
            "--mode global",
            "--restart-condition none",
            $"--name {cleanupSvcName}",
            "--mount type=bind,source=/var/run/docker.sock,target=/var/run/docker.sock",
            "docker:cli",
            "sh", "-c",
            $"'docker volume ls -q --filter name={stackName}_ | xargs -r docker volume rm 2>&1; echo done'");

        _logger.LogInformation("Deploying global volume-cleanup service on all swarm nodes for {StackName}", stackName);
        var (svcExit, svcOut, svcErr) = await _ssh.RunCommandAsync(_currentHost!, createCmd);

        if (svcExit != 0)
        {
            _logger.LogWarning("Global volume cleanup service creation failed: {Err}", svcErr);
        }
        else
        {
            // Wait for the cleanup tasks to finish on all nodes
            _logger.LogInformation("Waiting for volume cleanup tasks to complete on all nodes...");
            await Task.Delay(10000);
        }

        // Remove the cleanup service
        await _ssh.RunCommandAsync(_currentHost!,
            $"docker service rm {cleanupSvcName} 2>/dev/null || true");

        _logger.LogInformation("Volume cleanup complete for stack {StackName}", stackName);
        return true;
    }
}