using MyHomePage.Api.Common;
using MyHomePage.Api.Models.Dtos;
using MyHomePage.Api.Models.Entities;
using SqlSugar;

namespace MyHomePage.Api.Services;

/// <inheritdoc />
public class BookmarkService : IBookmarkService
{
    /// <summary>判定「用户未指定图标」的默认值集合。匹配其中之一则视为未指定，触发 favicon 自动抓取。</summary>
    private static readonly HashSet<string> DefaultIconNames = new(StringComparer.OrdinalIgnoreCase)
    {
        "link", "globe", "bookmark", "", null!   // null/empty 也算未指定
    };

    private readonly ISqlSugarClient _db;
    private readonly SyncLogHelper _sync;
    private readonly FaviconService _favicon;

    public BookmarkService(ISqlSugarClient db, SyncLogHelper sync, FaviconService favicon)
    {
        _db = db;
        _sync = sync;
        _favicon = favicon;
    }

    /// <inheritdoc />
    public async Task<List<BookmarkDto>> ListAsync(int? categoryId = null)
    {
        var query = _db.Queryable<Bookmark>().Where(b => !b.IsDeleted);
        if (categoryId.HasValue)
            query = query.Where(b => b.CategoryId == categoryId.Value);

        var list = await query
            .OrderBy(b => b.Sort)
            .OrderBy(b => b.Id)
            .ToListAsync();

        return list.Select(ToDto).ToList();
    }

    /// <inheritdoc />
    public async Task<BookmarkDto?> GetByIdAsync(int id)
    {
        var b = await _db.Queryable<Bookmark>().InSingleAsync(id);
        return b is null || b.IsDeleted ? null : ToDto(b);
    }

    /// <inheritdoc />
    public async Task<BookmarkDto> CreateAsync(BookmarkUpsertRequest request)
    {
        Validate(request);
        // 校验分类存在
        var catExists = await _db.Queryable<Category>().AnyAsync(c => c.Id == request.CategoryId);
        if (!catExists) throw new BusinessException("分类不存在", 400);

        var now = DateTime.UtcNow;
        var entity = new Bookmark
        {
            CategoryId = request.CategoryId,
            Title = request.Title.Trim(),
            Url = request.Url.Trim(),
            Description = request.Description?.Trim(),
            Icon = request.Icon,
            IconType = request.IconType ?? "lucide",
            IconUrl = request.IconUrl,
            ColorBg = NormalizeColor(request.ColorBg),
            Sort = request.Sort,
            IsDeleted = false,
            CreatedAt = now,
            UpdatedAt = now
        };
        entity.Id = await _db.Insertable(entity).ExecuteReturnIdentityAsync();

        // P31：未指定图标时自动抓取网站 favicon（失败静默用默认，不影响主记录创建）
        await MaybeFetchFaviconAsync(entity);

        await _sync.WriteAsync("bookmark", entity.Id, "create");
        return ToDto(entity);
    }

    /// <inheritdoc />
    public async Task<BookmarkDto> UpdateAsync(int id, BookmarkUpsertRequest request)
    {
        Validate(request);
        var entity = await _db.Queryable<Bookmark>().InSingleAsync(id)
            ?? throw new BusinessException("链接不存在", 404);

        entity.CategoryId = request.CategoryId;
        entity.Title = request.Title.Trim();
        entity.Url = request.Url.Trim();
        entity.Description = request.Description?.Trim();
        entity.Icon = request.Icon;
        entity.IconType = request.IconType ?? "lucide";
        entity.IconUrl = request.IconUrl;
        entity.ColorBg = NormalizeColor(request.ColorBg);   // P28 修复：原代码漏了 ColorBg，导致 PUT 后仍是旧值
        entity.Sort = request.Sort;
        entity.UpdatedAt = DateTime.UtcNow;

        await _db.Updateable(entity).ExecuteCommandAsync();

        // P31：URL 变了 或 图标从「自定义」回到「未指定」时，重新触发 favicon 抓取
        if (IsIconUnspecified(entity))
        {
            await MaybeFetchFaviconAsync(entity);
        }

        await _sync.WriteAsync("bookmark", id, "update");
        return ToDto(entity);
    }

    /// <summary>
    /// P31：判定链接是否「未指定图标」（即需要自动抓 favicon 的状态）：
    ///  - iconUrl 为空（用户没上传图片）
    ///  - iconType 为 lucide 或 null（即非 image / 非 emoji）
    ///  - icon 字段是默认值（"link" / "globe" / "bookmark" / 空）
    /// </summary>
    private static bool IsIconUnspecified(Bookmark b)
    {
        if (!string.IsNullOrEmpty(b.IconUrl)) return false;
        if (b.IconType == "image" || b.IconType == "emoji") return false;
        var name = (b.Icon ?? "").Trim();
        return DefaultIconNames.Contains(name);
    }

    /// <summary>
    /// P31：抓取并写入 favicon。失败静默（不影响主流程）。
    /// 成功后：entity.IconType = "favicon"，entity.IconUrl = /uploads/yyyy/MM/dd/favicons/xxx.ext
    /// </summary>
    private async Task MaybeFetchFaviconAsync(Bookmark entity)
    {
        if (!IsIconUnspecified(entity)) return;
        try
        {
            var iconUrl = await _favicon.FetchAndSaveAsync(entity.Url);
            if (!string.IsNullOrEmpty(iconUrl))
            {
                entity.IconType = "favicon";
                entity.IconUrl = iconUrl;
                entity.Icon = null;
                entity.UpdatedAt = DateTime.UtcNow;
                await _db.Updateable(entity)
                    .UpdateColumns(it => new { it.IconType, it.IconUrl, it.Icon, it.UpdatedAt })
                    .ExecuteCommandAsync();
            }
        }
        catch
        {
            // 静默吞掉异常（favicon 抓取失败不影响链接创建/更新）
        }
    }

    /// <inheritdoc />
    public async Task DeleteAsync(int id)
    {
        var entity = await _db.Queryable<Bookmark>().InSingleAsync(id)
            ?? throw new BusinessException("链接不存在", 404);

        entity.IsDeleted = true;
        entity.UpdatedAt = DateTime.UtcNow;
        await _db.Updateable(entity).ExecuteCommandAsync();
        await _sync.WriteAsync("bookmark", id, "delete");
    }

    private static void Validate(BookmarkUpsertRequest req)
    {
        if (string.IsNullOrWhiteSpace(req.Title)) throw new BusinessException("标题不能为空", 400);
        if (string.IsNullOrWhiteSpace(req.Url)) throw new BusinessException("URL 不能为空", 400);
        if (req.Title.Length > 128) throw new BusinessException("标题不能超过 128 字符", 400);
        if (req.Url.Length > 512) throw new BusinessException("URL 过长", 400);
        if (!Uri.TryCreate(req.Url, UriKind.Absolute, out _)) throw new BusinessException("URL 格式不正确", 400);
    }

    private static BookmarkDto ToDto(Bookmark b) => BookmarkDto.FromEntity(b);

    /// <summary>
    /// 规范化颜色：空串视为 null；仅保留 #hex / rgb(...) / hsl(...) 格式。无效则置 null。
    /// 长度上限 32（够 rgb / hsl / 短 hex / 长 hex）。
    /// </summary>
    private static string? NormalizeColor(string? color)
    {
        if (string.IsNullOrWhiteSpace(color)) return null;
        var c = color.Trim();
        if (c.Length > 32) return null;
        if (c.StartsWith('#') && (c.Length == 4 || c.Length == 7 || c.Length == 9)) return c;
        if (c.StartsWith("rgb", StringComparison.OrdinalIgnoreCase) && c.EndsWith(')')) return c;
        if (c.StartsWith("hsl", StringComparison.OrdinalIgnoreCase) && c.EndsWith(')')) return c;
        return null;
    }
}