import Foundation
import Observation
import OrgSocialKit

@Observable @MainActor
final class SearchViewModel {

    var query = ""
    var isTagSearch = false
    var results: [OrgSocialPost] = []
    var isLoading = false
    var errorMessage: String?

    private let relayClient = RelayClient()
    private let fetcher = FeedFetcher()

    var relayURL: URL {
        let raw = UserDefaults.standard.string(forKey: "relayURL") ?? "https://relay.org-social.org"
        return URL(string: raw) ?? URL(string: "https://relay.org-social.org")!
    }

    func search() async {
        let trimmed = query.trimmingCharacters(in: .whitespaces)
        guard !trimmed.isEmpty else { return }
        isLoading = true
        errorMessage = nil
        results = []
        defer { isLoading = false }

        do {
            let postURLs = try await relayClient.searchPostURLs(query: trimmed, isTag: isTagSearch, from: relayURL)
            results = try await resolvePosts(from: postURLs)
        } catch {
            errorMessage = error.localizedDescription
        }
    }

    private func resolvePosts(from postURLs: [String]) async throws -> [OrgSocialPost] {
        var byFeed: [String: [String]] = [:]
        for postURL in postURLs {
            guard let hashIdx = postURL.lastIndex(of: "#") else { continue }
            let feedStr = String(postURL[..<hashIdx])
            byFeed[feedStr, default: []].append(postURL)
        }

        var resolved: [OrgSocialPost] = []
        try await withThrowingTaskGroup(of: [OrgSocialPost].self) { group in
            for (feedStr, urls) in byFeed {
                guard let feedURL = URL(string: feedStr) else { continue }
                let timestamps = Set(urls.compactMap { $0.components(separatedBy: "#").last })
                group.addTask { [fetcher] in
                    guard let content = try? await fetcher.fetch(from: feedURL) else { return [] }
                    var profile = OrgSocialParser().parse(content)
                    profile.feedURL = feedURL
                    return profile.posts.filter { timestamps.contains($0.timestamp) }.map { post in
                        var p = post
                        p.authorNick = profile.nick
                        p.authorURL = feedURL
                        p.authorAvatar = profile.avatar
                        p.feedURL = feedURL
                        return p
                    }
                }
            }
            for try await posts in group {
                resolved.append(contentsOf: posts)
            }
        }
        return resolved.sorted { $0.date > $1.date }
    }
}