@page "/"
@inject SongCatalogService Catalog
@inject SiteSettingsService SiteSettings
@inject IJSRuntime Js
@inject ISnackbar Snackbar

<PageTitle>洛星瓷歌单</PageTitle>

<section class="song-page">
    <div class="page-heading">
        <div>
            <MudText Typo="Typo.h1">洛星瓷歌单</MudText>
            <MudText Typo="Typo.body1" Color="Color.Secondary">快速查找会唱的歌，复制点歌文案，也可以给歌曲补充标签。</MudText>
        </div>
        <MudPaper Class="asset-slot character-slot" Elevation="0">
            <MudIcon Icon="@Icons.Material.Filled.AutoAwesome" />
            <span>角色图占位</span>
        </MudPaper>
    </div>

    <MudPaper Class="search-panel" Elevation="0">
        <MudTextField T="string"
                      Value="_search"
                      ValueChanged="OnSearchChanged"
                      Immediate="true"
                      DebounceInterval="180"
                      Placeholder="搜索歌名或标签"
                      Variant="Variant.Outlined"
                      Adornment="Adornment.Start"
                      AdornmentIcon="@Icons.Material.Filled.Search"
                      Clearable="true" />

        @if (_selectedTag is not null)
        {
            <div class="active-filter">
                <MudChip T="string" Color="Color.Primary" Variant="Variant.Filled" OnClose="ClearTagFilter">
                    标签：@_selectedTag
                </MudChip>
            </div>
        }

        @if (_allTags.Count > 0)
        {
            <div class="tag-cloud" aria-label="标签筛选">
                @foreach (var tag in _allTags.Take(32))
                {
                    <MudChip T="string"
                             Color="@(_selectedTag == tag ? Color.Primary : Color.Info)"
                             Variant="@(_selectedTag == tag ? Variant.Filled : Variant.Outlined)"
                             OnClick="@(() => SelectTag(tag))">
                        @tag
                    </MudChip>
                }
            </div>
        }
    </MudPaper>

    @if (_isLoading)
    {
        <div class="loading-row">
            <MudProgressCircular Indeterminate="true" Color="Color.Primary" />
        </div>
    }
    else if (_songs.Count == 0)
    {
        <MudPaper Class="empty-state" Elevation="0">
            <MudIcon Icon="@Icons.Material.Filled.LibraryMusic" Size="Size.Large" />
            <MudText Typo="Typo.h6">歌单还是空的</MudText>
            <MudText Color="Color.Secondary">之后导入歌曲后，这里会显示可搜索的曲目。</MudText>
        </MudPaper>
    }
    else
    {
        <div class="song-grid">
            @foreach (var song in _songs)
            {
                <MudPaper Class="song-card" Elevation="0">
                    <div class="song-card-main">
                        <MudText Typo="Typo.h6">@song.Title</MudText>
                        <div class="song-tags">
                            @foreach (var tag in song.Tags)
                            {
                                <MudChip T="string" Size="Size.Small" Variant="Variant.Outlined" Color="Color.Info" OnClick="@(() => SelectTag(tag))">
                                    @tag
                                </MudChip>
                            }
                        </div>
                    </div>

                    <div class="song-card-actions">
                        <MudButton Variant="Variant.Filled"
                                   Color="Color.Primary"
                                   StartIcon="@Icons.Material.Filled.ContentCopy"
                                   OnClick="@(() => CopyRequest(song.Title))">
                            复制点歌
                        </MudButton>
                    </div>

                    <div class="viewer-tag-row">
                        <MudTextField T="string"
                                      Value="@song.NewTag"
                                      ValueChanged="@((string value) => song.NewTag = value)"
                                      Placeholder="添加标签"
                                      Variant="Variant.Outlined"
                                      Margin="Margin.Dense" />
                        <MudIconButton Icon="@Icons.Material.Filled.Add"
                                       Color="Color.Primary"
                                       Variant="Variant.Filled"
                                       Disabled="@string.IsNullOrWhiteSpace(song.NewTag)"
                                       OnClick="@(() => AddTag(song))" />
                    </div>
                </MudPaper>
            }
        </div>
    }
</section>

@code {
    private readonly List<SongCardState> _songs = [];
    private readonly List<string> _allTags = [];
    private string _search = string.Empty;
    private string? _selectedTag;
    private string _requestTemplate = "点歌《{title}》";
    private bool _isLoading = true;

    protected override async Task OnInitializedAsync()
    {
        _requestTemplate = await SiteSettings.GetRequestTemplateAsync();
        await LoadAsync();
    }

    private async Task OnSearchChanged(string value)
    {
        _search = value;
        await LoadAsync();
    }

    private async Task SelectTag(string tag)
    {
        _selectedTag = _selectedTag == tag ? null : tag;
        await LoadAsync();
    }

    private async Task ClearTagFilter()
    {
        _selectedTag = null;
        await LoadAsync();
    }

    private async Task LoadAsync()
    {
        _isLoading = true;
        var songs = await Catalog.SearchSongsAsync(_search, _selectedTag);
        var tags = await Catalog.GetVisibleTagsAsync();

        _songs.Clear();
        _songs.AddRange(songs.Select(SongCardState.From));
        _allTags.Clear();
        _allTags.AddRange(tags);
        _isLoading = false;
    }

    private async Task CopyRequest(string title)
    {
        var request = SiteSettingsService.FormatRequest(_requestTemplate, title);
        await Js.InvokeVoidAsync("navigator.clipboard.writeText", request);
        Snackbar.Add($"已复制：{request}", Severity.Success);
    }

    private async Task AddTag(SongCardState song)
    {
        try
        {
            await Catalog.AddViewerTagAsync(song.Id, song.NewTag);
            Snackbar.Add("标签已添加", Severity.Success);
            await LoadAsync();
        }
        catch (InvalidOperationException ex)
        {
            Snackbar.Add(ex.Message, Severity.Warning);
        }
    }

    private sealed class SongCardState
    {
        public int Id { get; init; }
        public string Title { get; init; } = string.Empty;
        public IReadOnlyList<string> Tags { get; init; } = [];
        public string NewTag { get; set; } = string.Empty;

        public static SongCardState From(SongListItem item)
        {
            return new SongCardState
            {
                Id = item.Id,
                Title = item.Title,
                Tags = item.Tags
            };
        }
    }
}