using System.IO;
using System.Text.Json;
using System.Text.Json.Nodes;
using MaksIT.UScheduler.ScheduleManager.Models;

namespace MaksIT.UScheduler.ScheduleManager.Services;

/// <summary>
/// Service for loading and saving scriptsettings.json files.
/// </summary>
public class ScriptSettingsService
{
    private static readonly JsonSerializerOptions JsonOptions = new()
    {
        PropertyNameCaseInsensitive = true,
        WriteIndented = true
    };

    /// <summary>
    /// Scans a directory for scriptsettings.json files and loads their schedule configurations.
    /// </summary>
    public List<ScriptSchedule> LoadScriptsFromDirectory(string examplesPath)
    {
        var schedules = new List<ScriptSchedule>();

        if (!Directory.Exists(examplesPath))
            return schedules;

        var settingsFiles = Directory.GetFiles(examplesPath, "scriptsettings.json", SearchOption.AllDirectories);

        foreach (var filePath in settingsFiles)
        {
            try
            {
                var schedule = LoadScheduleFromFile(filePath);
                if (schedule != null)
                    schedules.Add(schedule);
            }
            catch
            {
                // Skip files that can't be parsed
            }
        }

        return schedules;
    }

    /// <summary>
    /// Loads the schedule configuration from a single scriptsettings.json file.
    /// </summary>
    public ScriptSchedule? LoadScheduleFromFile(string filePath)
    {
        if (!File.Exists(filePath))
            return null;

        var json = File.ReadAllText(filePath);
        var doc = JsonNode.Parse(json);

        if (doc == null)
            return null;

        var title = doc["title"]?.GetValue<string>() ?? Path.GetDirectoryName(filePath) ?? "Unknown";
        var name = doc["name"]?.GetValue<string>();
        // Use name from JSON, or title with " Script Settings" suffix stripped for listbox display
        var displayName = !string.IsNullOrWhiteSpace(name)
            ? name
            : StripScriptSettingsSuffix(title);
        var schedule = new ScriptSchedule
        {
            FilePath = filePath,
            Name = displayName,
            Title = title
        };

        var scheduleNode = doc["schedule"];
        if (scheduleNode != null)
        {
            schedule.RunMonth = GetStringArray(scheduleNode["runMonth"]);
            schedule.RunWeekday = GetStringArray(scheduleNode["runWeekday"]);
            schedule.RunTime = GetStringArray(scheduleNode["runTime"]);
            schedule.MinIntervalMinutes = scheduleNode["minIntervalMinutes"]?.GetValue<int>() ?? 10;
        }

        return schedule;
    }

    /// <summary>
    /// Saves only the schedule section back to the scriptsettings.json file,
    /// preserving all other content.
    /// </summary>
    public void SaveScheduleToFile(ScriptSchedule schedule)
    {
        if (!File.Exists(schedule.FilePath))
            throw new FileNotFoundException("Script settings file not found.", schedule.FilePath);

        var json = File.ReadAllText(schedule.FilePath);
        var doc = JsonNode.Parse(json);

        if (doc == null)
            throw new InvalidOperationException("Failed to parse JSON file.");

        // Update or create the schedule section
        var scheduleNode = new JsonObject
        {
            ["runMonth"] = new JsonArray(schedule.RunMonth.Select(m => JsonValue.Create(m)).ToArray()),
            ["runWeekday"] = new JsonArray(schedule.RunWeekday.Select(d => JsonValue.Create(d)).ToArray()),
            ["runTime"] = new JsonArray(schedule.RunTime.Select(t => JsonValue.Create(t)).ToArray()),
            ["minIntervalMinutes"] = schedule.MinIntervalMinutes
        };

        doc["schedule"] = scheduleNode;

        // Write back with proper formatting
        var options = new JsonWriterOptions { Indented = true };
        using var stream = File.Create(schedule.FilePath);
        using var writer = new Utf8JsonWriter(stream, options);
        doc.WriteTo(writer);
    }

    /// <summary>Strips " Script Settings" (case-insensitive) from the end of a title for listbox display.</summary>
    private static string StripScriptSettingsSuffix(string title)
    {
        const string suffix = " Script Settings";
        if (title.Length > suffix.Length && title.EndsWith(suffix, StringComparison.OrdinalIgnoreCase))
            return title[..^suffix.Length].TrimEnd();
        return title;
    }

    private static List<string> GetStringArray(JsonNode? node)
    {
        if (node is not JsonArray array)
            return [];

        return array
            .Where(item => item != null)
            .Select(item => item!.GetValue<string>())
            .ToList();
    }
}