using Microsoft.AspNetCore.Hosting;
using SeaHaven.Services.Helpers;

namespace Api.SeaHavenIndustries.Helper
{
    public interface IWorkOrderPrivateFileStorage
    {
        Task<string> SaveAsync(int workOrderId, IFormFile file, CancellationToken cancellationToken = default);
        bool TryResolvePhysicalPath(string? storedValue, out string physicalPath);
        void TryDelete(string? storedValue);
        string ToDownloadApiPath(int workOrderId, string kind, int? mediaId = null);
    }

    /// <summary>
    /// Stores board completion/media files under ContentRoot/App_Data (not wwwroot).
    /// DB values are relative keys: workorder-files/{workOrderId}/{guid}{ext}
    /// </summary>
    public sealed class WorkOrderPrivateFileStorage : IWorkOrderPrivateFileStorage
    {
        public const string RelativeRoot = "workorder-files";
        private readonly IWebHostEnvironment _env;

        public WorkOrderPrivateFileStorage(IWebHostEnvironment env)
        {
            _env = env;
        }

        private string RootPath => Path.GetFullPath(Path.Combine(_env.ContentRootPath, "App_Data", RelativeRoot));

        public async Task<string> SaveAsync(int workOrderId, IFormFile file, CancellationToken cancellationToken = default)
        {
            var clientName = file.FileName;
            if (string.IsNullOrWhiteSpace(clientName) && !string.IsNullOrWhiteSpace(file.ContentDisposition))
            {
                try
                {
                    clientName = System.Net.Http.Headers.ContentDispositionHeaderValue
                        .Parse(file.ContentDisposition).FileName?.Trim('"');
                }
                catch
                {
                    clientName = null;
                }
            }

            if (!WorkOrderUploadFileRules.TryGetAllowedExtension(clientName, out var extension, out var error))
                throw new InvalidOperationException(error ?? "Invalid file.");

            var serverName = WorkOrderUploadFileRules.BuildServerFileName(extension);
            var relativeKey = $"{RelativeRoot}/{workOrderId}/{serverName}".Replace('\\', '/');
            var directory = Path.Combine(RootPath, workOrderId.ToString());
            var fullPath = Path.GetFullPath(Path.Combine(directory, serverName));

            if (!fullPath.StartsWith(RootPath, StringComparison.OrdinalIgnoreCase))
                throw new InvalidOperationException("Resolved path escapes storage root.");

            Directory.CreateDirectory(directory);
            await using (var stream = System.IO.File.Create(fullPath))
            {
                await file.CopyToAsync(stream, cancellationToken);
            }

            return relativeKey;
        }

        public bool TryResolvePhysicalPath(string? storedValue, out string physicalPath)
        {
            physicalPath = string.Empty;
            if (string.IsNullOrWhiteSpace(storedValue))
                return false;

            // Accept relative keys; reject absolute URLs / wwwroot legacy paths here.
            var normalized = storedValue.Replace('\\', '/').TrimStart('/');
            if (!normalized.StartsWith(RelativeRoot + "/", StringComparison.OrdinalIgnoreCase))
                return false;

            var relative = normalized[(RelativeRoot.Length + 1)..];
            var candidate = Path.GetFullPath(Path.Combine(RootPath, relative));
            if (!candidate.StartsWith(RootPath, StringComparison.OrdinalIgnoreCase))
                return false;

            if (!System.IO.File.Exists(candidate))
                return false;

            physicalPath = candidate;
            return true;
        }

        public void TryDelete(string? storedValue)
        {
            if (!TryResolvePhysicalPath(storedValue, out var path))
                return;

            try
            {
                System.IO.File.Delete(path);
            }
            catch
            {
                // best-effort cleanup
            }
        }

        public string ToDownloadApiPath(int workOrderId, string kind, int? mediaId = null)
            => kind switch
            {
                "completion" => $"/api/workorders/{workOrderId}/completion-doc/file",
                "media" when mediaId.HasValue => $"/api/workorders/{workOrderId}/media/{mediaId.Value}/file",
                _ => $"/api/workorders/{workOrderId}/media/file"
            };
    }
}