using CommandLine;
using StackExchange.Redis;
using System;
using System.Collections.Generic;
using System.Linq;
using RedisManager.Utils;

namespace RedisManager.Commands
{
    /// <summary>
    /// Contains command line options and implementations for Redis scripting operations.
    /// Provides functionality for EVAL, EVALSHA, SCRIPT LOAD, SCRIPT EXISTS, and SCRIPT FLUSH commands.
    /// </summary>
    [Verb("eval", HelpText = "Evaluate a Lua script.")]
    public class EvalOptions
    {
        [Option('i', "instance", Required = true, HelpText = "Instance name.")]
        public string Instance { get; set; }
        [Value(0, MetaName = "script", Required = true, HelpText = "Lua script.")]
        public string Script { get; set; }
        [Option("keys", Required = false, HelpText = "Comma-separated keys.")]
        public string Keys { get; set; }
        [Option("args", Required = false, HelpText = "Comma-separated arguments.")]
        public string Args { get; set; }
    }

    [Verb("evalsha", HelpText = "Evaluate a Lua script by its SHA1 hash.")]
    public class EvalShaOptions
    {
        [Option('i', "instance", Required = true, HelpText = "Instance name.")]
        public string Instance { get; set; }
        [Value(0, MetaName = "sha1", Required = true, HelpText = "SHA1 hash.")]
        public string Sha1 { get; set; }
        [Option("keys", Required = false, HelpText = "Comma-separated keys.")]
        public string Keys { get; set; }
        [Option("args", Required = false, HelpText = "Comma-separated arguments.")]
        public string Args { get; set; }
    }

    [Verb("scriptload", HelpText = "Load a Lua script into the script cache.")]
    public class ScriptLoadOptions
    {
        [Option('i', "instance", Required = true, HelpText = "Instance name.")]
        public string Instance { get; set; }
        [Value(0, MetaName = "script", Required = true, HelpText = "Lua script.")]
        public string Script { get; set; }
    }

    [Verb("scriptexists", HelpText = "Check if scripts exist in the script cache.")]
    public class ScriptExistsOptions
    {
        [Option('i', "instance", Required = true, HelpText = "Instance name.")]
        public string Instance { get; set; }
        [Value(0, MetaName = "sha1s", Min = 1, Required = true, HelpText = "SHA1 hashes.")]
        public IEnumerable<string> Sha1s { get; set; }
    }

    [Verb("scriptflush", HelpText = "Remove all scripts from the script cache.")]
    public class ScriptFlushOptions
    {
        [Option('i', "instance", Required = true, HelpText = "Instance name.")]
        public string Instance { get; set; }
    }

    public static class ScriptingCommands
    {
        /// <summary>
        /// Executes the EVAL command to evaluate a Lua script.
        /// </summary>
        /// <param name="opts">The EvalOptions containing instance, script, keys, and arguments.</param>
        /// <param name="config">The RedisManager configuration.</param>
        /// <returns>Exit code (0 for success, non-zero for failure).</returns>
        public static int RunEval(EvalOptions opts, Config config)
        {
            var instance = RedisUtils.GetInstance(config, opts.Instance);
            using var redis = RedisUtils.ConnectRedis(instance);
            var db = redis.GetDatabase();
            var keys = string.IsNullOrEmpty(opts.Keys) ? Array.Empty<RedisKey>() : opts.Keys.Split(',').Select(k => (RedisKey)k.Trim()).ToArray();
            var args = string.IsNullOrEmpty(opts.Args) ? Array.Empty<RedisValue>() : opts.Args.Split(',').Select(a => (RedisValue)a.Trim()).ToArray();
            var result = db.ScriptEvaluate(opts.Script, keys, args);
            Console.WriteLine(Output.Green(result.ToString()));
            return 0;
        }

        /// <summary>
        /// Executes the EVALSHA command to evaluate a Lua script by its SHA1 hash.
        /// </summary>
        /// <param name="opts">The EvalShaOptions containing instance, sha1, keys, and arguments.</param>
        /// <param name="config">The RedisManager configuration.</param>
        /// <returns>Exit code (0 for success, non-zero for failure).</returns>
        public static int RunEvalSha(EvalShaOptions opts, Config config)
        {
            var instance = RedisUtils.GetInstance(config, opts.Instance);
            using var redis = RedisUtils.ConnectRedis(instance);
            var db = redis.GetDatabase();
            var keys = string.IsNullOrEmpty(opts.Keys) ? Array.Empty<RedisKey>() : opts.Keys.Split(',').Select(k => (RedisKey)k.Trim()).ToArray();
            var args = string.IsNullOrEmpty(opts.Args) ? Array.Empty<RedisValue>() : opts.Args.Split(',').Select(a => (RedisValue)a.Trim()).ToArray();
            var result = db.ScriptEvaluate(opts.Sha1, keys, args);
            Console.WriteLine(Output.Green(result.ToString()));
            return 0;
        }

        /// <summary>
        /// Executes the SCRIPT LOAD command to load a Lua script into the script cache.
        /// </summary>
        /// <param name="opts">The ScriptLoadOptions containing instance and script.</param>
        /// <param name="config">The RedisManager configuration.</param>
        /// <returns>Exit code (0 for success, non-zero for failure).</returns>
        public static int RunScriptLoad(ScriptLoadOptions opts, Config config)
        {
            var instance = RedisUtils.GetInstance(config, opts.Instance);
            using var redis = RedisUtils.ConnectRedis(instance);
            var server = redis.GetServer(redis.GetEndPoints().First());
            var sha1Bytes = server.ScriptLoad(opts.Script);
            // Convert byte[] to hex string
            var sha1 = BitConverter.ToString(sha1Bytes).Replace("-", string.Empty).ToLower();
            Console.WriteLine(Output.Green(sha1));
            return 0;
        }

        /// <summary>
        /// Executes the SCRIPT EXISTS command to check if scripts exist in the script cache.
        /// </summary>
        /// <param name="opts">The ScriptExistsOptions containing instance and SHA1 hashes.</param>
        /// <param name="config">The RedisManager configuration.</param>
        /// <returns>Exit code (0 for success, non-zero for failure).</returns>
        public static int RunScriptExists(ScriptExistsOptions opts, Config config)
        {
            var instance = RedisUtils.GetInstance(config, opts.Instance);
            using var redis = RedisUtils.ConnectRedis(instance);
            var server = redis.GetServer(redis.GetEndPoints().First());
            foreach (var sha in opts.Sha1s)
            {
                var exists = server.ScriptExists(sha);
                Console.WriteLine(Output.Green($"{sha}: {(exists ? "YES" : "NO")}"));
            }
            return 0;
        }

        /// <summary>
        /// Executes the SCRIPT FLUSH command to remove all scripts from the script cache.
        /// </summary>
        /// <param name="opts">The ScriptFlushOptions containing instance.</param>
        /// <param name="config">The RedisManager configuration.</param>
        /// <returns>Exit code (0 for success, non-zero for failure).</returns>
        public static int RunScriptFlush(ScriptFlushOptions opts, Config config)
        {
            var instance = RedisUtils.GetInstance(config, opts.Instance);
            using var redis = RedisUtils.ConnectRedis(instance);
            var server = redis.GetServer(redis.GetEndPoints().First());
            server.ScriptFlush();
            Console.WriteLine(Output.Green("Script cache flushed."));
            return 0;
        }
    }
}