using Avalonia_Common.Core;
using Avalonia_Services.Core;
using System.Text.Json;

namespace Avalonia_Services.Services.FileLibrary
{
    public sealed class FileLibraryEndpointService(IFileLibraryService fileLibrary) : IFileLibraryEndpointService
    {
        private static readonly JsonSerializerOptions JsonOptions = new()
        {
            PropertyNameCaseInsensitive = true,
        };

        public async Task<object?> GetDrivesAsync(ServiceEndpointContext ctx)
        {
            return ResponseHelper.Ok(await fileLibrary.GetDrivesAsync());
        }

        public async Task<object?> GetDirectoriesAsync(ServiceEndpointContext ctx)
        {
            var path = ctx.Query.GetValueOrDefault("path");
            return ResponseHelper.Ok(await fileLibrary.GetDirectoriesAsync(path));
        }

        public async Task<object?> GetRootsAsync(ServiceEndpointContext ctx)
        {
            return ResponseHelper.Ok(await fileLibrary.GetRootsAsync());
        }

        public async Task<object?> AddRootAsync(ServiceEndpointContext ctx)
        {
            var request = ReadBody<AddLibraryRootRequest>(ctx);
            return ResponseHelper.Ok(await fileLibrary.AddRootAsync(request), "文件库目录已添加并完成扫描。");
        }

        public async Task<object?> SetRootEnabledAsync(ServiceEndpointContext ctx)
        {
            var request = ReadBody<UpdateLibraryRootRequest>(ctx);
            return ResponseHelper.Ok(await fileLibrary.SetRootEnabledAsync(request), "文件库目录状态已更新。");
        }

        public async Task<object?> DeleteRootAsync(ServiceEndpointContext ctx)
        {
            var request = ReadBody<DeleteLibraryRootRequest>(ctx);
            await fileLibrary.DeleteRootAsync(request);
            return ResponseHelper.Succeed("文件库目录已删除。");
        }

        public async Task<object?> ScanRootAsync(ServiceEndpointContext ctx)
        {
            var request = ReadBody<ScanLibraryRootRequest>(ctx);
            return ResponseHelper.Ok(await fileLibrary.ScanRootAsync(request.Id), "文件库目录扫描完成。");
        }

        public async Task<object?> SearchFilesAsync(ServiceEndpointContext ctx)
        {
            return await fileLibrary.SearchFilesAsync(ctx);
        }

        public async Task<object?> GetFileAsync(ServiceEndpointContext ctx)
        {
            var id = ReadId(ctx);
            var file = await fileLibrary.GetFileAsync(id);
            return file is null
                ? ResponseHelper.Failure(404, "文件不存在或尚未扫描入库。")
                : ResponseHelper.Ok(file);
        }

        public async Task<object?> GetTextPreviewAsync(ServiceEndpointContext ctx)
        {
            var id = ReadId(ctx);
            var preview = await fileLibrary.GetTextPreviewAsync(id);
            return preview is null
                ? ResponseHelper.Failure(404, "文本文件不存在或无法预览。")
                : ResponseHelper.Ok(preview);
        }

        private static T ReadBody<T>(ServiceEndpointContext ctx)
        {
            if (string.IsNullOrWhiteSpace(ctx.Body))
            {
                throw new InvalidOperationException("请求体不能为空。");
            }

            var body = JsonSerializer.Deserialize<T>(ctx.Body, JsonOptions);
            return body ?? throw new InvalidOperationException("请求体格式错误。");
        }

        private static int ReadId(ServiceEndpointContext ctx)
        {
            if (int.TryParse(ctx.Query.GetValueOrDefault("id"), out var id) && id > 0)
            {
                return id;
            }

            throw new InvalidOperationException("id 参数无效。");
        }
    }
}