using System;
using System.IO;
using System.Linq;
using Microsoft.Extensions.Logging;
using MediaBrowser.Common.Configuration;

namespace Jellyfin.Plugin.Seasonals;

public class ScriptInjector
{
    private readonly IApplicationPaths _appPaths;
    private readonly ILogger<ScriptInjector> _logger;
    private const string ScriptTag = "<script src=\"Seasonals/Resources/seasonals.js\"></script>";
    private const string Marker = "</body>";

    public ScriptInjector(IApplicationPaths appPaths, ILogger<ScriptInjector> logger)
    {
        _appPaths = appPaths;
        _logger = logger;
    }

    public void Inject()
    {
        try
        {
            var webPath = GetWebPath();
            if (string.IsNullOrEmpty(webPath))
            {
                _logger.LogWarning("Could not find Jellyfin web path. Script injection skipped.");
                return;
            }

            var indexPath = Path.Combine(webPath, "index.html");
            if (!File.Exists(indexPath))
            {
                _logger.LogWarning("index.html not found at {Path}. Script injection skipped.", indexPath);
                return;
            }

            var content = File.ReadAllText(indexPath);
            if (content.Contains(ScriptTag))
            {
                _logger.LogInformation("Seasonals script already injected.");
                return;
            }

            var newContent = content.Replace(Marker, $"{ScriptTag}\n{Marker}");
            if (newContent == content)
            {
                _logger.LogWarning("Could not find closing body tag in index.html. Script injection skipped.");
                return;
            }

            File.WriteAllText(indexPath, newContent);
            _logger.LogInformation("Successfully injected Seasonals script into index.html.");
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error injecting Seasonals script.");
        }
    }

    public void Remove()
    {
        try
        {
            var webPath = GetWebPath();
            if (string.IsNullOrEmpty(webPath)) return;

            var indexPath = Path.Combine(webPath, "index.html");
            if (!File.Exists(indexPath)) return;

            var content = File.ReadAllText(indexPath);
            if (!content.Contains(ScriptTag)) return;

            var newContent = content.Replace(ScriptTag, "").Replace($"{ScriptTag}\n", "");
            File.WriteAllText(indexPath, newContent);
            _logger.LogInformation("Successfully removed Seasonals script from index.html.");
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error removing Seasonals script.");
        }
    }

    private string? GetWebPath()
    {
        // Try to find the web path using IApplicationPaths
        // Note: The property name might vary depending on the Jellyfin version, 
        // but usually it's accessible via the configuration or standard paths.
        // For this plugin context, we'll try to rely on the standard path structure if IApplicationPaths doesn't expose it directly 
        // or if we need to infer it.
        
        // In many Jellyfin versions, appPaths.WebPath is the property.
        // However, since we are in a plugin, we might need to use reflection if the interface doesn't expose it in the reference assembly,
        // or just assume it's there. 
        
        // Let's try to use the property if it exists.
        // If the compilation fails, we will adjust.
        // For now, we assume 'WebPath' is available on IApplicationPaths implementation 
        // but it might not be on the interface in the nuget package.
        
        // Workaround: Check known locations if property is missing or use reflection.
        
        // Attempt 1: Reflection to get WebPath property (safest if interface varies)
        var prop = _appPaths.GetType().GetProperty("WebPath");
        if (prop != null)
        {
            return prop.GetValue(_appPaths) as string;
        }

        // Attempt 2: Guess based on ProgramDataPath (common in Windows)
        // Usually <ProgramData>/jellyfin/web or <InstallDir>/jellyfin-web
        
        // Let's try to look relative to the application executable if possible, but that's hard from a plugin.
        
        return null;
    }
}