import Foundation
import FoundationModels

/// The tool the on-device model calls to look things up in the user's library.
/// It is the bridge between `LanguageModelSession` (generation) and the
/// Spotlight index (retrieval) — together they form on-device RAG over the
/// private bookmark corpus.
struct BookmarkSearchTool: Tool {
    let name = "searchBookmarks"
    let description = """
    Search the user's saved bookmarks. Returns the most relevant bookmarks with \
    their title, website, description, and URL. Call this for any question about \
    what the user has saved, read, or wants to find again.
    """

    @Generable
    struct Arguments {
        @Guide(description: "Keywords or a short phrase describing what to look for in the saved bookmarks")
        var query: String
    }

    func call(arguments: Arguments) async throws -> String {
        Log.tool.info("searchBookmarks invoked query=\(arguments.query, privacy: .public)")
        let hits = await SpotlightBookmarkSearch.run(query: arguments.query, limit: 8)
        Log.tool.info("searchBookmarks returned \(hits.count, privacy: .public) bookmarks")
        guard !hits.isEmpty else {
            return "No bookmarks matched \"\(arguments.query)\"."
        }
        return hits.enumerated().map { idx, b in
            var line = "\(idx + 1). \(b.title)"
            if !b.host.isEmpty { line += " — \(b.host)" }
            if !b.description.isEmpty { line += "\n   \(b.description)" }
            if !b.url.isEmpty { line += "\n   \(b.url)" }
            return line
        }.joined(separator: "\n")
    }
}