using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.StaticFiles;
using System.Runtime.Versioning;
using System.Text.Json;
using System.Windows.Forms;

namespace YD_TrainingCompetition_Api.Controllers;

// LibraryController 支持桌面端"用资源管理器选取任意赛事文件夹"：
// - scan：按约定子目录扫描所选文件夹，返回其中的背景/口令/LOGO/秩序册资源
// - file：把磁盘上任意已存在的文件通过 http 提供给前端（图片/音频/秩序册）
[ApiController]
[Route("api/[controller]")]
public sealed class LibraryController : ControllerBase
{
    private static readonly string[] BackgroundDirs = { "背景", "背景图" };
    private static readonly string[] PasswordDirs = { "口令" };
    private static readonly string[] LogoDirs = { "赛事LOGO", "赛事logo" };
    private static readonly string[] RosterDirs = { "秩序册" };

    private static readonly HashSet<string> ImageExt = new(StringComparer.OrdinalIgnoreCase)
    { ".jpg", ".jpeg", ".png", ".webp", ".gif", ".bmp", ".svg" };
    private static readonly HashSet<string> RosterExt = new(StringComparer.OrdinalIgnoreCase)
    { ".txt", ".csv", ".xlsx", ".xls" };
    private static readonly HashSet<string> PasswordExt = new(StringComparer.OrdinalIgnoreCase)
    { ".mp3" };

    private static readonly FileExtensionContentTypeProvider ContentTypeProvider = new();

    // 在本机弹出系统文件夹选择对话框（供浏览器开发环境使用；桌面端优先走 Electron）。
    [HttpPost("pick-folder")]
    [SupportedOSPlatform("windows")]
    public IActionResult PickFolder()
    {
        string? selectedPath = null;

        var thread = new Thread(() =>
        {
            using var dialog = new FolderBrowserDialog
            {
                Description = "选择赛事文件夹",
                UseDescriptionForTitle = true,
                ShowNewFolderButton = false,
            };

            if (dialog.ShowDialog() == DialogResult.OK)
            {
                selectedPath = dialog.SelectedPath;
            }
        });
        thread.SetApartmentState(ApartmentState.STA);
        thread.Start();
        thread.Join();

        if (string.IsNullOrWhiteSpace(selectedPath))
        {
            return Ok(new { canceled = true, path = (string?)null });
        }

        return Ok(new { canceled = false, path = selectedPath });
    }

    // 扫描用户选取的赛事文件夹，结构与原 static/manifest.json 中单个赛事一致。
    [HttpGet("scan")]
    public IActionResult Scan([FromQuery] string path)
    {
        if (string.IsNullOrWhiteSpace(path))
        {
            return BadRequest(new { message = "缺少文件夹路径" });
        }

        var folderPath = path.Trim();
        if (!Directory.Exists(folderPath))
        {
            return NotFound(new { message = $"文件夹不存在：{folderPath}" });
        }

        var folder = new DirectoryInfo(folderPath).Name;
        var displayName = ReadDisplayName(folderPath) ?? folder;

        var result = new
        {
            id = folderPath,
            name = displayName,
            folder,
            folderPath,
            backgrounds = ListFiles(folderPath, BackgroundDirs, ImageExt),
            passwords = ListFiles(folderPath, PasswordDirs, PasswordExt),
            logos = ListFiles(folderPath, LogoDirs, ImageExt),
            rosters = ListFiles(folderPath, RosterDirs, RosterExt),
        };

        return Ok(result);
    }

    // 提供磁盘上任意已存在文件（仅限本机桌面端调用）。支持音视频拖动定位。
    [HttpGet("file")]
    public IActionResult GetFile([FromQuery] string path)
    {
        if (string.IsNullOrWhiteSpace(path))
        {
            return BadRequest(new { message = "缺少文件路径" });
        }

        var filePath = path.Trim();
        if (!System.IO.File.Exists(filePath))
        {
            return NotFound(new { message = $"文件不存在：{filePath}" });
        }

        if (!ContentTypeProvider.TryGetContentType(filePath, out var contentType))
        {
            contentType = "application/octet-stream";
        }

        return PhysicalFile(filePath, contentType, enableRangeProcessing: true);
    }

    private List<object> ListFiles(string folderPath, string[] subDirCandidates, HashSet<string> allowedExt)
    {
        var subDir = ResolveSubDir(folderPath, subDirCandidates);
        var dir = Path.Combine(folderPath, subDir);
        if (!Directory.Exists(dir))
        {
            return new List<object>();
        }

        return Directory
            .EnumerateFiles(dir)
            .Where(file =>
            {
                var name = Path.GetFileName(file);
                return !name.StartsWith("~$", StringComparison.Ordinal)
                    && allowedExt.Contains(Path.GetExtension(file));
            })
            .OrderBy(file => Path.GetFileName(file), StringComparer.CurrentCulture)
            .Select(file => (object)new
            {
                file = Path.GetFileName(file),
                path = BuildFileUrl(file),
            })
            .ToList();
    }

    private static string ResolveSubDir(string folderPath, string[] candidates)
    {
        foreach (var name in candidates)
        {
            if (Directory.Exists(Path.Combine(folderPath, name)))
            {
                return name;
            }
        }

        return candidates[0];
    }

    // 返回前端可直接请求的绝对地址，避免 resolveStaticUrl 误编码查询串。
    private string BuildFileUrl(string absolutePath)
    {
        var encoded = Uri.EscapeDataString(absolutePath);
        return $"{Request.Scheme}://{Request.Host}/api/library/file?path={encoded}";
    }

    private static string? ReadDisplayName(string folderPath)
    {
        var metaPath = Path.Combine(folderPath, "event.json");
        if (!System.IO.File.Exists(metaPath))
        {
            return null;
        }

        try
        {
            using var doc = JsonDocument.Parse(System.IO.File.ReadAllText(metaPath));
            if (doc.RootElement.TryGetProperty("displayName", out var prop)
                && prop.ValueKind == JsonValueKind.String)
            {
                return prop.GetString();
            }
        }
        catch
        {
            // 忽略损坏的 event.json
        }

        return null;
    }
}