using System;
using System.CommandLine;
using System.Globalization;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.DependencyInjection;
using StellaOps.Cli.Extensions;
using StellaOps.Doctor.Engine;
using StellaOps.Doctor.Models;
using StellaOps.Doctor.Output;

namespace StellaOps.Cli.Commands;

/// <summary>
/// Builds the stella doctor command for diagnostic checks.
/// </summary>
internal static class DoctorCommandGroup
{
    internal static Command BuildDoctorCommand(
        IServiceProvider services,
        Option<bool> verboseOption,
        CancellationToken cancellationToken)
    {
        var doctor = new Command("doctor", "Run diagnostic checks on Stella Ops installation and environment.");

        // Sub-commands
        doctor.Add(BuildRunCommand(services, verboseOption, cancellationToken));
        doctor.Add(BuildListCommand(services, verboseOption, cancellationToken));

        return doctor;
    }

    private static Command BuildRunCommand(
        IServiceProvider services,
        Option<bool> verboseOption,
        CancellationToken cancellationToken)
    {
        var formatOption = new Option<string>("--format", new[] { "-f" })
        {
            Description = "Output format: text (default), json, markdown"
        };
        formatOption.SetDefaultValue("text");

        var modeOption = new Option<string?>("--mode", new[] { "-m" })
        {
            Description = "Run mode: quick (fast checks only), normal (default), full (all checks including slow ones)"
        };

        var categoryOption = new Option<string?>("--category", new[] { "-c" })
        {
            Description = "Filter checks by category (e.g., Core, Database, Security)"
        };

        var tagOption = new Option<string[]>("--tag", new[] { "-t" })
        {
            Description = "Filter checks by tag (e.g., quick, connectivity). Can be specified multiple times.",
            Arity = ArgumentArity.ZeroOrMore
        };

        var checkOption = new Option<string?>("--check")
        {
            Description = "Run a specific check by ID (e.g., check.core.disk)"
        };

        var parallelOption = new Option<int?>("--parallel", new[] { "-p" })
        {
            Description = "Maximum parallel check executions (default: 4)"
        };

        var timeoutOption = new Option<int?>("--timeout")
        {
            Description = "Per-check timeout in seconds (default: 30)"
        };

        var outputOption = new Option<string?>("--output", new[] { "-o" })
        {
            Description = "Write output to file instead of stdout"
        };

        var failOnWarnOption = new Option<bool>("--fail-on-warn")
        {
            Description = "Exit with non-zero code on warnings (default: only fail on errors)"
        };

        var run = new Command("run", "Execute diagnostic checks.")
        {
            formatOption,
            modeOption,
            categoryOption,
            tagOption,
            checkOption,
            parallelOption,
            timeoutOption,
            outputOption,
            failOnWarnOption,
            verboseOption
        };

        run.SetAction(async (parseResult, ct) =>
        {
            var format = parseResult.GetValue(formatOption) ?? "text";
            var mode = parseResult.GetValue(modeOption);
            var category = parseResult.GetValue(categoryOption);
            var tags = parseResult.GetValue(tagOption) ?? [];
            var checkId = parseResult.GetValue(checkOption);
            var parallel = parseResult.GetValue(parallelOption) ?? 4;
            var timeout = parseResult.GetValue(timeoutOption) ?? 30;
            var output = parseResult.GetValue(outputOption);
            var failOnWarn = parseResult.GetValue(failOnWarnOption);
            var verbose = parseResult.GetValue(verboseOption);

            await RunDoctorAsync(
                services,
                format,
                mode,
                category,
                tags,
                checkId,
                parallel,
                timeout,
                output,
                failOnWarn,
                verbose,
                cancellationToken);
        });

        return run;
    }

    private static Command BuildListCommand(
        IServiceProvider services,
        Option<bool> verboseOption,
        CancellationToken cancellationToken)
    {
        var categoryOption = new Option<string?>("--category", new[] { "-c" })
        {
            Description = "Filter by category"
        };

        var tagOption = new Option<string[]>("--tag", new[] { "-t" })
        {
            Description = "Filter by tag",
            Arity = ArgumentArity.ZeroOrMore
        };

        var list = new Command("list", "List available diagnostic checks.")
        {
            categoryOption,
            tagOption,
            verboseOption
        };

        list.SetAction((parseResult, ct) =>
        {
            var category = parseResult.GetValue(categoryOption);
            var tags = parseResult.GetValue(tagOption) ?? [];
            var verbose = parseResult.GetValue(verboseOption);

            return ListChecksAsync(services, category, tags, verbose, cancellationToken);
        });

        return list;
    }

    private static async Task RunDoctorAsync(
        IServiceProvider services,
        string format,
        string? mode,
        string? category,
        string[] tags,
        string? checkId,
        int parallel,
        int timeout,
        string? outputPath,
        bool failOnWarn,
        bool verbose,
        CancellationToken ct)
    {
        var engine = services.GetRequiredService<DoctorEngine>();

        var runMode = ParseRunMode(mode);

        var options = new DoctorRunOptions
        {
            Mode = runMode,
            Categories = category != null ? [category] : null,
            Tags = tags.Length > 0 ? tags : null,
            CheckIds = checkId != null ? [checkId] : null,
            Parallelism = parallel,
            Timeout = TimeSpan.FromSeconds(timeout)
        };

        // Progress reporting for verbose mode
        IProgress<DoctorCheckProgress>? progress = null;
        if (verbose)
        {
            progress = new Progress<DoctorCheckProgress>(p =>
            {
                Console.WriteLine($"[{p.Completed}/{p.Total}] {p.CheckId} - {p.Severity}");
            });
        }

        var report = await engine.RunAsync(options, progress, ct);

        // Format output
        var formatter = GetFormatter(format);
        var output = formatter.Format(report);

        // Write output
        if (!string.IsNullOrEmpty(outputPath))
        {
            await File.WriteAllTextAsync(outputPath, output, ct);
            Console.WriteLine($"Report written to: {outputPath}");
        }
        else
        {
            Console.WriteLine(output);
        }

        // Set exit code
        SetExitCode(report, failOnWarn);
    }

    private static async Task ListChecksAsync(
        IServiceProvider services,
        string? category,
        string[] tags,
        bool verbose,
        CancellationToken ct)
    {
        var engine = services.GetRequiredService<DoctorEngine>();

        var options = new DoctorRunOptions
        {
            Categories = category != null ? [category] : null,
            Tags = tags.Length > 0 ? tags : null
        };

        var checks = engine.ListChecks(options);

        Console.WriteLine($"Available diagnostic checks ({checks.Count}):");
        Console.WriteLine();

        string? currentCategory = null;

        foreach (var check in checks.OrderBy(c => c.Category).ThenBy(c => c.CheckId))
        {
            if (check.Category != currentCategory)
            {
                currentCategory = check.Category;
                Console.WriteLine($"## {currentCategory ?? "Uncategorized"}");
                Console.WriteLine();
            }

            Console.WriteLine($"  {check.CheckId}");
            Console.WriteLine($"    Name: {check.Name}");
            if (verbose)
            {
                Console.WriteLine($"    Description: {check.Description}");
                Console.WriteLine($"    Plugin: {check.PluginId}");
                Console.WriteLine($"    Tags: {string.Join(", ", check.Tags)}");
                Console.WriteLine($"    Estimated: {check.EstimatedDuration.TotalSeconds:F1}s");
            }
            Console.WriteLine();
        }

        await Task.CompletedTask;
    }

    private static DoctorRunMode ParseRunMode(string? mode)
    {
        return mode?.ToLowerInvariant() switch
        {
            "quick" => DoctorRunMode.Quick,
            "full" => DoctorRunMode.Full,
            _ => DoctorRunMode.Normal
        };
    }

    private static IDoctorReportFormatter GetFormatter(string format)
    {
        return format.ToLowerInvariant() switch
        {
            "json" => new JsonReportFormatter(),
            "markdown" or "md" => new MarkdownReportFormatter(),
            _ => new TextReportFormatter()
        };
    }

    private static void SetExitCode(DoctorReport report, bool failOnWarn)
    {
        var exitCode = report.OverallSeverity switch
        {
            DoctorSeverity.Fail => CliExitCodes.DoctorFailed,
            DoctorSeverity.Warn when failOnWarn => CliExitCodes.DoctorWarning,
            _ => 0
        };

        if (exitCode != 0)
        {
            Environment.ExitCode = exitCode;
        }
    }
}