@using Microsoft.AspNetCore.Components.Forms
@using NexusReader.Application.Abstractions.Services
@using NexusReader.Application.Queries.Reader
@using NexusReader.Application.Commands.Library
@using System.Net.Http.Json
@inject IEpubMetadataExtractor MetadataExtractor
@inject ILogger<BookIngestionModal> Logger
@inject HttpClient Http
@inject IReaderNavigationService ReaderNavigation
@inject IJSRuntime JSRuntime
@implements IAsyncDisposable

@if (IsOpen)
{
    <div class="modal-backdrop" @onclick="CloseModal">
        <div class="modal-content glass-panel" @onclick:stopPropagation>
            <div class="modal-header">
                <h2>Add New Book</h2>
                <button class="close-btn" @onclick="CloseModal">
                    <svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><line x1="18" y1="6" x2="6" y2="18"></line><line x1="6" y1="6" x2="18" y2="18"></line></svg>
                </button>
            </div>

            <div class="modal-body">
                <div class="parsing-state shimmer" style="@(IsParsing ? "display:flex;" : "display:none;")">
                    <div class="shimmer-content">
                        <div class="spinner"></div>
                        <p>Scanning metadata...</p>
                    </div>
                </div>
                
                <div class="verification-state" style="@(IsVerifying && !IsParsing ? "display:flex;" : "display:none;")">
                    @if (Metadata != null)
                    {
                        <div class="verification-layout">
                            <div class="cover-preview">
                                @if (Metadata.CoverImage != null)
                                {
                                    <img src="data:image/jpeg;base64,@Convert.ToBase64String(Metadata.CoverImage)" alt="Cover Preview" />
                                }
                                else
                                {
                                    <div class="glowing-placeholder">
                                        <svg xmlns="http://www.w3.org/2000/svg" width="48" height="48" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M4 19.5A2.5 2.5 0 0 1 6.5 17H20"></path><path d="M6.5 2H20v20H6.5A2.5 2.5 0 0 1 4 19.5v-15A2.5 2.5 0 0 1 6.5 2z"></path></svg>
                                    </div>
                                }
                            </div>
                            
                            <div class="verification-form">
                                <div class="form-group">
                                    <label>Title</label>
                                    <input type="text" class="form-input" @bind="Metadata.Title" placeholder="Enter book title" />
                                </div>
                                <div class="form-group">
                                    <label>Author</label>
                                    <input type="text" class="form-input" @bind="Metadata.Author" placeholder="Enter author name" />
                                </div>
                            </div>
                        </div>

                        <div class="actions">
                            <NexusButton Class="btn-secondary" OnClick="Reset" Disabled="IsIngesting">Back</NexusButton>
                            <NexusButton Class="@($"btn-primary {(IsIngesting ? "btn-loading" : "")}")" 
                                         OnClick="SaveToLibrary" 
                                         Disabled="IsIngesting">
                                @(IsIngesting ? "" : "Save to Library")
                            </NexusButton>
                        </div>
                    }
                </div>
                
                <div class="upload-state @(_isDragging ? "drag-over" : "")" 
                     style="@(!IsParsing && !IsVerifying ? "display:flex;" : "display:none;")"
                     @ondragenter="OnDragEnter" 
                     @ondragleave="OnDragLeave">
                    <div class="drop-zone">
                        <InputFile id="epub-upload" OnChange="HandleFileSelected" accept=".epub" class="file-input-cover" />
                        <div class="drop-zone-content">
                            <svg xmlns="http://www.w3.org/2000/svg" width="48" height="48" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M21 15v4a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2v-4"></path><polyline points="17 8 12 3 7 8"></polyline><line x1="12" y1="3" x2="12" y2="15"></line></svg>
                            <p>Drag and drop your .epub file here</p>
                            <span>or click to browse</span>
                        </div>
                    </div>
                </div>

                
                @if (!string.IsNullOrEmpty(ErrorMessage))
                {
                    <div class="error-message">
                        @ErrorMessage
                    </div>
                }
            </div>
        </div>
    </div>
}



@code {
    /// <summary>
    /// Gets or sets a value indicating whether the modal is open.
    /// </summary>
    [Parameter]
    public bool IsOpen { get; set; }

    /// <summary>
    /// Event triggered when the IsOpen state changes.
    /// </summary>
    [Parameter]
    public EventCallback<bool> IsOpenChanged { get; set; }

    private bool _isDragging;
    private bool IsParsing { get; set; }
    private bool IsVerifying { get; set; }
    private bool IsIngesting { get; set; }
    private LocalEpubMetadata? Metadata { get; set; }
    private string? ErrorMessage { get; set; }
    private byte[]? _epubBytes;
    
    // Allow up to 50 MB
    private const long MaxFileSize = 50 * 1024 * 1024;

    private async Task CloseModal()
    {
        IsOpen = false;
        Reset();
        await IsOpenChanged.InvokeAsync(false);
    }

    private void Reset()
    {
        IsParsing = false;
        IsVerifying = false;
        IsIngesting = false;
        Metadata = null;
        ErrorMessage = null;
        _isDragging = false;
        _epubBytes = null;
    }

    private void OnDragEnter() => _isDragging = true;
    private void OnDragLeave() => _isDragging = false;

    private async Task HandleFileSelected(InputFileChangeEventArgs e)
    {
        _isDragging = false;
        var file = e.File;
        
        if (file == null) return;
        
        if (!file.Name.EndsWith(".epub", StringComparison.OrdinalIgnoreCase))
        {
            ErrorMessage = "Only .epub files are supported.";
            return;
        }

        ErrorMessage = null;
        IsParsing = true;
        StateHasChanged();

        try
        {
            using var stream = file.OpenReadStream(MaxFileSize);
            using var memoryStream = new MemoryStream();
            await stream.CopyToAsync(memoryStream);
            _epubBytes = memoryStream.ToArray();
            
            memoryStream.Position = 0;
            var result = await MetadataExtractor.ExtractMetadataAsync(memoryStream);

            if (result.IsSuccess)
            {
                Metadata = result.Value;
                IsVerifying = true;
            }
            else
            {
                ErrorMessage = result.Errors.FirstOrDefault()?.Message ?? "Failed to parse EPUB.";
            }
        }
        catch (Exception ex)
        {
            Logger.LogError(ex, "Error uploading EPUB");
            ErrorMessage = $"An unexpected error occurred: {ex.Message}";
        }
        finally
        {
            IsParsing = false;
            StateHasChanged();
        }
    }

    private async Task SaveToLibrary()
    {
        if (Metadata == null || _epubBytes == null) return;

        IsIngesting = true;
        ErrorMessage = null;
        StateHasChanged();

        try
        {
            var request = new IngestEbookRequest(
                Metadata.Title,
                Metadata.Author,
                Metadata.CoverImage != null ? Convert.ToBase64String(Metadata.CoverImage) : null,
                Convert.ToBase64String(_epubBytes)
            );

            var response = await Http.PostAsJsonAsync("api/library/ingest", request);

            if (response.IsSuccessStatusCode)
            {
                var result = await response.Content.ReadFromJsonAsync<IngestResult>();
                if (result != null)
                {
                    await CloseModal();
                    ReaderNavigation.NavigateToBook(result.Id);
                }
            }
            else
            {
                ErrorMessage = await response.Content.ReadAsStringAsync();
            }
        }
        catch (Exception ex)
        {
            Logger.LogError(ex, "Error during ingestion");
            ErrorMessage = "Failed to save book to library. Please try again.";
        }
        finally
        {
            IsIngesting = false;
            StateHasChanged();
        }
    }

    private record IngestResult(Guid Id);

    public ValueTask DisposeAsync()
    {
        // Clear the large byte array so it is eligible for GC even if the component is cached.
        _epubBytes = null;
        return ValueTask.CompletedTask;
    }
}