import Foundation

struct HistoryEntry: Codable, Equatable {
    let role: String
    let text: String
    let timestamp: Date
}

/// Last 50 final transcript entries persisted as JSON in UserDefaults.
@MainActor
final class TranscriptHistory: ObservableObject {
    @Published private(set) var entries: [HistoryEntry] = []

    private static let key = "voice_history"
    private static let maxEntries = 50

    init() {
        if let raw = UserDefaults.standard.string(forKey: Self.key),
           let data = raw.data(using: .utf8),
           let decoded = try? JSONDecoder().decode([HistoryEntry].self, from: data) {
            entries = Array(decoded.suffix(Self.maxEntries))
        }
    }

    func add(role: String, text: String) {
        guard !text.isEmpty else { return }
        entries.append(HistoryEntry(role: role, text: text, timestamp: Date()))
        if entries.count > Self.maxEntries {
            entries.removeFirst(entries.count - Self.maxEntries)
        }
        persist()
    }

    func clear() {
        entries.removeAll()
        persist()
    }

    private func persist() {
        guard let data = try? JSONEncoder().encode(entries) else { return }
        UserDefaults.standard.set(String(decoding: data, as: UTF8.self), forKey: Self.key)
    }
}