@page "/admin"
@attribute [Authorize]
@inject SongCatalogService Catalog
@inject SiteSettingsService SiteSettings
@inject ISnackbar Snackbar

<PageTitle>歌单管理</PageTitle>

<section class="admin-page">
    <div class="page-heading compact">
        <div>
            <MudText Typo="Typo.h1">歌单管理</MudText>
            <MudText Typo="Typo.body1" Color="Color.Secondary">添加歌曲、隐藏曲目、清理标签和调整点歌文案。</MudText>
        </div>
        <MudButton Href="/admin/logout" Variant="Variant.Outlined" Color="Color.Primary" StartIcon="@Icons.Material.Filled.Logout">
            退出
        </MudButton>
    </div>

    <MudGrid Spacing="3">
        <MudItem xs="12" md="7">
            <MudPaper Class="admin-panel" Elevation="0">
                <div class="panel-title-row">
                    <MudText Typo="Typo.h5">歌曲</MudText>
                    <MudChip T="string" Color="Color.Info" Variant="Variant.Outlined">@_songs.Count 首</MudChip>
                </div>

                <div class="admin-add-row">
                    <MudTextField T="string"
                                  Value="_newSongTitle"
                                  ValueChanged="@((string value) => _newSongTitle = value)"
                                  Label="新增歌名"
                                  Variant="Variant.Outlined"
                                  Margin="Margin.Dense" />
                    <MudButton Variant="Variant.Filled"
                               Color="Color.Primary"
                               StartIcon="@Icons.Material.Filled.Add"
                               Disabled="@string.IsNullOrWhiteSpace(_newSongTitle)"
                               OnClick="CreateSong">
                        添加
                    </MudButton>
                </div>

                @if (_songs.Count == 0)
                {
                    <MudText Class="admin-muted" Color="Color.Secondary">还没有歌曲。之后可以从这里手动添加，或直接导入数据库。</MudText>
                }
                else
                {
                    <div class="admin-list">
                        @foreach (var song in _songs)
                        {
                            <MudPaper Class="@($"admin-list-item {(song.IsHidden ? "is-hidden" : string.Empty)}")" Elevation="0">
                                <MudTextField T="string"
                                              Value="@song.Title"
                                              ValueChanged="@((string value) => song.Title = value)"
                                              Label="歌名"
                                              Variant="Variant.Outlined"
                                              Margin="Margin.Dense" />
                                <MudCheckBox T="bool"
                                             Value="@song.IsHidden"
                                             ValueChanged="@((bool value) => song.IsHidden = value)"
                                             Label="隐藏" />
                                <div class="song-tags admin-song-tags">
                                    @foreach (var tag in song.Tags)
                                    {
                                        <MudChip T="string" Size="Size.Small" Variant="Variant.Outlined" Color="Color.Info">@tag</MudChip>
                                    }
                                </div>
                                <div class="admin-actions">
                                    <MudButton Variant="Variant.Filled" Color="Color.Primary" StartIcon="@Icons.Material.Filled.Save" OnClick="@(() => SaveSong(song))">
                                        保存
                                    </MudButton>
                                    <MudButton Variant="Variant.Outlined" Color="Color.Error" StartIcon="@Icons.Material.Filled.Delete" OnClick="@(() => DeleteSong(song))">
                                        删除
                                    </MudButton>
                                </div>
                            </MudPaper>
                        }
                    </div>
                }
            </MudPaper>
        </MudItem>

        <MudItem xs="12" md="5">
            <MudPaper Class="admin-panel" Elevation="0">
                <MudText Typo="Typo.h5">站点设置</MudText>
                <MudTextField T="string"
                              Value="_requestTemplate"
                              ValueChanged="@((string value) => _requestTemplate = value)"
                              Label="点歌文案模板"
                              HelperText="使用 {title} 代表歌名"
                              Variant="Variant.Outlined" />
                <MudButton Variant="Variant.Filled" Color="Color.Primary" StartIcon="@Icons.Material.Filled.Save" OnClick="SaveRequestTemplate">
                    保存设置
                </MudButton>
            </MudPaper>

            <MudPaper Class="admin-panel" Elevation="0">
                <div class="panel-title-row">
                    <MudText Typo="Typo.h5">标签</MudText>
                    <MudChip T="string" Color="Color.Info" Variant="Variant.Outlined">@_tags.Count 个</MudChip>
                </div>

                @if (_tags.Count == 0)
                {
                    <MudText Class="admin-muted" Color="Color.Secondary">暂无标签。</MudText>
                }
                else
                {
                    <div class="tag-admin-list">
                        @foreach (var tag in _tags)
                        {
                            <MudPaper Class="tag-admin-item" Elevation="0">
                                <MudTextField T="string"
                                              Value="@tag.Name"
                                              ValueChanged="@((string value) => tag.Name = value)"
                                              Label="@($"标签，{tag.SongCount} 首")"
                                              Variant="Variant.Outlined"
                                              Margin="Margin.Dense" />
                                <MudTextField T="string"
                                              Value="@tag.MergeTarget"
                                              ValueChanged="@((string value) => tag.MergeTarget = value)"
                                              Label="合并到"
                                              Variant="Variant.Outlined"
                                              Margin="Margin.Dense" />
                                <div class="admin-actions">
                                    <MudButton Variant="Variant.Filled" Color="Color.Primary" StartIcon="@Icons.Material.Filled.Save" OnClick="@(() => RenameTag(tag))">
                                        改名
                                    </MudButton>
                                    <MudButton Variant="Variant.Outlined" Color="Color.Info" StartIcon="@Icons.Material.Filled.CallMerge" Disabled="@string.IsNullOrWhiteSpace(tag.MergeTarget)" OnClick="@(() => MergeTag(tag))">
                                        合并
                                    </MudButton>
                                    <MudIconButton Icon="@Icons.Material.Filled.Delete" Color="Color.Error" Variant="Variant.Outlined" OnClick="@(() => DeleteTag(tag))" />
                                </div>
                            </MudPaper>
                        }
                    </div>
                }
            </MudPaper>
        </MudItem>
    </MudGrid>
</section>

@code {
    private readonly List<AdminSongState> _songs = [];
    private readonly List<AdminTagState> _tags = [];
    private string _newSongTitle = string.Empty;
    private string _requestTemplate = "点歌《{title}》";

    protected override async Task OnInitializedAsync()
    {
        await LoadAsync();
    }

    private async Task LoadAsync()
    {
        var songs = await Catalog.GetAdminSongsAsync();
        var tags = await Catalog.GetAdminTagsAsync();
        _requestTemplate = await SiteSettings.GetRequestTemplateAsync();

        _songs.Clear();
        _songs.AddRange(songs.Select(AdminSongState.From));
        _tags.Clear();
        _tags.AddRange(tags.Select(AdminTagState.From));
    }

    private async Task CreateSong()
    {
        await RunAdminAction(async () =>
        {
            await Catalog.CreateSongAsync(_newSongTitle);
            _newSongTitle = string.Empty;
            Snackbar.Add("歌曲已添加", Severity.Success);
        });
    }

    private async Task SaveSong(AdminSongState song)
    {
        await RunAdminAction(async () =>
        {
            await Catalog.UpdateSongAsync(song.Id, song.Title, song.IsHidden);
            Snackbar.Add("歌曲已保存", Severity.Success);
        });
    }

    private async Task DeleteSong(AdminSongState song)
    {
        await RunAdminAction(async () =>
        {
            await Catalog.DeleteSongAsync(song.Id);
            Snackbar.Add("歌曲已删除", Severity.Success);
        });
    }

    private async Task SaveRequestTemplate()
    {
        await RunAdminAction(async () =>
        {
            await SiteSettings.SaveRequestTemplateAsync(_requestTemplate);
            Snackbar.Add("设置已保存", Severity.Success);
        }, reload: false);
    }

    private async Task RenameTag(AdminTagState tag)
    {
        await RunAdminAction(async () =>
        {
            await Catalog.RenameTagAsync(tag.Id, tag.Name);
            Snackbar.Add("标签已更新", Severity.Success);
        });
    }

    private async Task MergeTag(AdminTagState tag)
    {
        await RunAdminAction(async () =>
        {
            await Catalog.MergeTagAsync(tag.Id, tag.MergeTarget);
            Snackbar.Add("标签已合并", Severity.Success);
        });
    }

    private async Task DeleteTag(AdminTagState tag)
    {
        await RunAdminAction(async () =>
        {
            await Catalog.DeleteTagAsync(tag.Id);
            Snackbar.Add("标签已删除", Severity.Success);
        });
    }

    private async Task RunAdminAction(Func<Task> action, bool reload = true)
    {
        try
        {
            await action();
            if (reload)
            {
                await LoadAsync();
            }
        }
        catch (InvalidOperationException ex)
        {
            Snackbar.Add(ex.Message, Severity.Warning);
        }
    }

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

        public static AdminSongState From(AdminSongItem item)
        {
            return new AdminSongState
            {
                Id = item.Id,
                Title = item.Title,
                IsHidden = item.IsHidden,
                Tags = item.Tags
            };
        }
    }

    private sealed class AdminTagState
    {
        public int Id { get; init; }
        public string Name { get; set; } = string.Empty;
        public string MergeTarget { get; set; } = string.Empty;
        public int SongCount { get; init; }

        public static AdminTagState From(AdminTagItem item)
        {
            return new AdminTagState
            {
                Id = item.Id,
                Name = item.Name,
                SongCount = item.SongCount
            };
        }
    }
}