import Foundation

@MainActor
public final class DictationController {
    public private(set) var state: DictationState = .idle {
        didSet { onStateChange?(state) }
    }
    public var onStateChange: ((DictationState) -> Void)?
    public var onError: ((String) -> Void)?

    private let recorder: AudioRecording
    private let transcriber: Transcriber
    private let cleaner: Cleaner
    private let inserter: TextInserting
    private let minimumSamples: Int

    /// - Parameter minimumSamples: 16 kHz samples; default is 0.3 s.
    public init(
        recorder: AudioRecording,
        transcriber: Transcriber,
        cleaner: Cleaner,
        inserter: TextInserting,
        minimumSamples: Int = 4_800
    ) {
        self.recorder = recorder
        self.transcriber = transcriber
        self.cleaner = cleaner
        self.inserter = inserter
        self.minimumSamples = minimumSamples
    }

    public func handle(_ event: HotkeyEvent) async {
        switch (event, state) {
        case (.pressed, .idle):
            do {
                try recorder.start()
                state = .recording
            } catch {
                onError?(error.localizedDescription)
            }
        case (.released, .recording):
            let samples = recorder.stop()
            guard samples.count >= minimumSamples else {
                state = .idle
                return
            }
            await process(samples)
        default:
            break
        }
    }

    private func process(_ samples: [Float]) async {
        defer { state = .idle }
        do {
            state = .transcribing
            let raw = try await transcriber.transcribe(samples)
            let text = raw.trimmingCharacters(in: .whitespacesAndNewlines)
            guard !text.isEmpty else { return }
            let cleaned = try await cleaner.clean(text, context: CleaningContext())
            state = .inserting
            try await inserter.insert(cleaned)
        } catch {
            onError?(error.localizedDescription)
        }
    }
}