using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http.Headers;
using System.Runtime.InteropServices;
using System.Threading;
using System.Threading.Tasks;
using GitHub.DistributedTask.Pipelines.ContextData;
using GitHub.DistributedTask.WebApi;
using GitHub.Services.Common;
using GitHub.Services.WebApi;
using Newtonsoft.Json;

namespace GitHub.Runner.Sdk
{
    public interface IRunnerActionPlugin
    {
        Task RunAsync(RunnerActionPluginExecutionContext executionContext, CancellationToken token);
    }

    public class RunnerActionPluginExecutionContext : ITraceWriter
    {
        private readonly string DebugEnvironmentalVariable = "ACTIONS_STEP_DEBUG";
        private VssConnection _connection;
        private RunnerWebProxy _webProxy;
        private readonly object _stdoutLock = new();
        private readonly ITraceWriter _trace; // for unit tests

        public RunnerActionPluginExecutionContext()
            : this(null)
        { }

        public RunnerActionPluginExecutionContext(ITraceWriter trace)
        {
            _trace = trace;
            this.Endpoints = new List<ServiceEndpoint>();
            this.Inputs = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
            this.Variables = new Dictionary<string, VariableValue>(StringComparer.OrdinalIgnoreCase);
        }

        public List<ServiceEndpoint> Endpoints { get; set; }
        public Dictionary<string, VariableValue> Variables { get; set; }
        public Dictionary<string, string> Inputs { get; set; }
        public DictionaryContextData Context { get; set; } = new DictionaryContextData();

        [JsonIgnore]
        public VssConnection VssConnection
        {
            get
            {
                if (_connection == null)
                {
                    _connection = InitializeVssConnection();
                }
                return _connection;
            }
        }

        [JsonIgnore]
        public RunnerWebProxy WebProxy
        {
            get
            {
                if (_webProxy == null)
                {
                    _webProxy = new RunnerWebProxy();
                }
                return _webProxy;
            }
        }

        public VssConnection InitializeVssConnection()
        {
            var headerValues = new List<ProductInfoHeaderValue>();
            headerValues.Add(new ProductInfoHeaderValue($"GitHubActionsRunner-Plugin", BuildConstants.RunnerPackage.Version));
            headerValues.Add(new ProductInfoHeaderValue($"({StringUtil.SanitizeUserAgentHeader(RuntimeInformation.OSDescription)})"));

            if (VssClientHttpRequestSettings.Default.UserAgent != null && VssClientHttpRequestSettings.Default.UserAgent.Count > 0)
            {
                headerValues.AddRange(VssClientHttpRequestSettings.Default.UserAgent);
            }

            VssClientHttpRequestSettings.Default.UserAgent = headerValues;
            VssHttpMessageHandler.DefaultWebProxy = this.WebProxy;
            ServiceEndpoint systemConnection = this.Endpoints.FirstOrDefault(e => string.Equals(e.Name, WellKnownServiceEndpointNames.SystemVssConnection, StringComparison.OrdinalIgnoreCase));
            ArgUtil.NotNull(systemConnection, nameof(systemConnection));
            ArgUtil.NotNull(systemConnection.Url, nameof(systemConnection.Url));

            VssCredentials credentials = VssUtil.GetVssCredential(systemConnection);
            ArgUtil.NotNull(credentials, nameof(credentials));
            return VssUtil.CreateConnection(systemConnection.Url, credentials);
        }

        public string GetInput(string name, bool required = false)
        {
            string value = null;
            if (this.Inputs.ContainsKey(name))
            {
                value = this.Inputs[name];
            }

            Debug($"Input '{name}': '{value ?? string.Empty}'");

            if (string.IsNullOrEmpty(value) && required)
            {
                throw new ArgumentNullException(name);
            }

            return value;
        }

        public void Info(string message)
        {
            Debug(message);
        }

        public void Verbose(string message)
        {
            Debug(message);
        }

        public void Error(string message)
        {
            Output($"##[error]{Escape(message)}");
        }

        public void Debug(string message)
        {
            var debugString = Variables.GetValueOrDefault(DebugEnvironmentalVariable)?.Value;
            if (StringUtil.ConvertToBoolean(debugString))
            {
                var multilines = message?.Replace("\r\n", "\n")?.Split("\n");
                if (multilines != null)
                {
                    foreach (var line in multilines)
                    {
                        Output($"##[debug]{Escape(line)}");
                    }
                }
            }
        }

        public void Warning(string message)
        {
            Output($"##[warning]{Escape(message)}");
        }

        public void Output(string message)
        {
            lock (_stdoutLock)
            {
                if (_trace == null)
                {
                    Console.WriteLine(message);
                }
                else
                {
                    _trace.Info(message);
                }
            }
        }

        public void AddMask(string secret)
        {
            Output($"##[add-mask]{Escape(secret)}");
        }

        public void Command(string command)
        {
            Output($"##[command]{Escape(command)}");
        }

        public void SetRepositoryPath(string repoName, string path, bool workspaceRepo)
        {
            Output($"##[internal-set-repo-path repoFullName={repoName};workspaceRepo={workspaceRepo.ToString()}]{path}");
        }

        public void SetIntraActionState(string name, string value)
        {
            Output($"##[save-state name={Escape(name)}]{Escape(value)}");
        }

        public String GetRunnerContext(string contextName)
        {
            this.Context.TryGetValue("runner", out var context);
            var runnerContext = context as DictionaryContextData;
            ArgUtil.NotNull(runnerContext, nameof(runnerContext));
            if (runnerContext.TryGetValue(contextName, out var data))
            {
                return data as StringContextData;
            }
            else
            {
                return null;
            }
        }

        public String GetGitHubContext(string contextName)
        {
            this.Context.TryGetValue("github", out var context);
            var githubContext = context as DictionaryContextData;
            ArgUtil.NotNull(githubContext, nameof(githubContext));
            if (githubContext.TryGetValue(contextName, out var data))
            {
                return data as StringContextData;
            }
            else
            {
                return null;
            }
        }

        private string Escape(string input)
        {
            foreach (var mapping in _commandEscapeMappings)
            {
                input = input.Replace(mapping.Key, mapping.Value);
            }

            return input;
        }

        private Dictionary<string, string> _commandEscapeMappings = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase)
        {
            { ";", "%3B" },
            { "\r", "%0D" },
            { "\n", "%0A" },
            { "]", "%5D" },
        };
    }
}
