using System.Text.Json;
using System.Text.Json.Serialization;
using FluidExplorer.Models;

namespace FluidExplorer.Services;

/// <summary>外观模式：默认跟随系统（深浅色自动切换）。</summary>
public enum AppThemeMode
{
    System,
    Light,
    Dark
}

public enum SearchScope
{
    /// <summary>全盘（走 NTFS 索引，Everything 式，毫秒级）。</summary>
    Global,
    /// <summary>仅当前文件夹及其子目录。</summary>
    CurrentFolder
}

public sealed class FolderViewState
{
    public ViewMode ViewMode { get; set; } = ViewMode.Details;
    public SortColumn SortColumn { get; set; } = SortColumn.Name;
    public SortDirection SortDirection { get; set; } = SortDirection.Ascending;
    public GroupBy GroupBy { get; set; } = GroupBy.None;
}

/// <summary>用户设置（%LOCALAPPDATA%\FluidExplorer\settings.json），失败时退回程序目录。</summary>
public sealed class AppSettings
{
    public AppThemeMode ThemeMode { get; set; } = AppThemeMode.System;

    // 视图
    public bool ShowHiddenFiles { get; set; }
    public bool ShowSystemFiles { get; set; }
    public bool ShowFileExtensions { get; set; } = true;
    public bool AlwaysShowCheckBoxes { get; set; }
    public bool ShowStatusBar { get; set; } = true;

    // 浏览
    public bool OpenFoldersInNewTab { get; set; }
    public bool DoubleClickToOpen { get; set; } = true;
    public bool RestoreTabsOnStartup { get; set; } = true;
    public string DefaultStartPath { get; set; } = "";
    public List<string> PinnedFolders { get; set; } = [];
    public List<string> RecentFolders { get; set; } = [];
    public List<string> OpenTabs { get; set; } = [];
    public bool DualPane { get; set; }

    // 搜索
    public SearchScope SearchScope { get; set; } = SearchScope.Global;
    public List<string> IndexedVolumes { get; set; } = [];
    public bool IndexOnStartup { get; set; } = true;
    public bool SearchAsYouType { get; set; } = true;

    // 文件操作
    public bool DeleteToRecycleBin { get; set; } = true;
    public ConflictPolicySetting DefaultConflictPolicy { get; set; } = ConflictPolicySetting.Ask;
    public bool ConfirmPermanentDelete { get; set; } = true;
    public bool KeepWindowOpenDuringOperations { get; set; } = true;

    // 动效（克制：只保留系统原生的必要动画）
    public bool AnimationsEnabled { get; set; } = true;

    // 窗口
    public double WindowLeft { get; set; } = double.NaN;
    public double WindowTop { get; set; } = double.NaN;
    public double WindowWidth { get; set; } = 1280;
    public double WindowHeight { get; set; } = 800;
    public bool WindowMaximized { get; set; }

    /// <summary>按文件夹记住视图方式（对齐资源管理器的"按文件夹记住视图设置"）。</summary>
    public Dictionary<string, FolderViewState> FolderViews { get; set; } = new(StringComparer.OrdinalIgnoreCase);

    [JsonIgnore]
    public string SettingsFilePath { get; private set; } = string.Empty;

    private static readonly JsonSerializerOptions JsonOptions = new()
    {
        WriteIndented = true,
        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
    };

    public static AppSettings Load()
    {
        foreach (var candidate in CandidatePaths())
        {
            try
            {
                if (!File.Exists(candidate)) continue;
                var json = File.ReadAllText(candidate);
                var loaded = JsonSerializer.Deserialize<AppSettings>(json, JsonOptions);
                if (loaded is null) continue;
                loaded.SettingsFilePath = candidate;
                return loaded;
            }
            catch
            {
                // 设置文件损坏时忽略，使用默认值
            }
        }

        var settings = new AppSettings();
        settings.SettingsFilePath = CandidatePaths().First();
        return settings;
    }

    public void Save()
    {
        foreach (var target in CandidatePaths())
        {
            try
            {
                var dir = Path.GetDirectoryName(target);
                if (!string.IsNullOrEmpty(dir)) Directory.CreateDirectory(dir);
                SettingsFilePath = target;
                File.WriteAllText(target, JsonSerializer.Serialize(this, JsonOptions));
                return;
            }
            catch
            {
                // 换下一个候选位置（例如沙箱/只读环境）
            }
        }
    }

    public FolderViewState GetFolderView(string path)
    {
        if (FolderViews.TryGetValue(path, out var state)) return state;
        state = new FolderViewState();
        FolderViews[path] = state;
        return state;
    }

    private static IEnumerable<string> CandidatePaths()
    {
        var localAppData = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData);
        if (!string.IsNullOrEmpty(localAppData))
            yield return Path.Combine(localAppData, "FluidExplorer", "settings.json");
        yield return Path.Combine(AppContext.BaseDirectory, "settings.json");
    }
}

public enum ConflictPolicySetting
{
    Ask,
    Replace,
    Skip,
    KeepBoth
}