//
//  SpeechService.swift
//  Zyquo MLX
//
//  Author: Simon-Pierre Boucher
//  Mail: contact@spboucher.ai
//

import Foundation

/// Transcription result from a speech model.
struct TranscriptionResult: Sendable {
    var text: String
    var language: String?
    var segments: Int
    var duration: TimeInterval
}

/// Speech-to-text via the Python bridge (mlx-whisper — Python-only per
/// docs/MLX-RESEARCH.md §2). Installs the pinned package on first use.
actor SpeechService {

    static let shared = SpeechService()

    /// Exact pin per docs/MLX-RESEARCH.md version snapshot.
    static let whisperPin = "mlx-whisper==0.4.3"

    private var whisperInstalled = false

    func transcribe(model: LocalModel, audio: URL) async throws -> TranscriptionResult {
        try await ensureWhisper()

        let start = Date()
        let stream = try await PythonRunner.shared.stream(
            script: "zyquo_transcribe",
            arguments: ["--model", model.directory.path, "--audio", audio.path])

        var text = ""
        var language: String?
        var segments = 0
        for try await event in stream {
            switch event.event {
            case "done":
                text = event.string("text") ?? ""
                language = event.string("language")
                segments = event.int("segments") ?? 0
            case "error":
                throw PythonRunnerError.processFailed(
                    exitCode: 1, stderr: event.string("message") ?? "transcription failed")
            default:
                break
            }
        }
        return TranscriptionResult(
            text: text, language: language, segments: segments,
            duration: Date().timeIntervalSince(start))
    }

    private func ensureWhisper() async throws {
        guard !whisperInstalled else { return }
        let env = PythonEnvironment.shared
        if await !env.isProvisioned {
            try await env.provision()
        }
        // Cheap idempotent install (uv resolves instantly when satisfied).
        try await env.install(pins: [Self.whisperPin])
        whisperInstalled = true
    }
}