amethyst/app/src/main/java/com/vitorpamplona/amethyst/service/tts/TextToSpeechHelper.kt

/**
 * Copyright (c) 2024 Vitor Pamplona
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
 * Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
package com.vitorpamplona.amethyst.service.tts

import android.content.Context
import android.util.Log
import androidx.lifecycle.Lifecycle
import androidx.lifecycle.LifecycleEventObserver
import androidx.lifecycle.LifecycleOwner
import java.lang.ref.WeakReference
import java.util.Locale

class TextToSpeechHelper private constructor(private val context: WeakReference<Context>) :
    LifecycleEventObserver {
        private val appContext
            get() = context.get()!!.applicationContext

        private var message: String? = null

        private var ttsEngine: TextToSpeechEngine? = null

        private var onStart: (() -> Unit)? = null

        private var onDoneListener: (() -> Unit)? = null

        private var onErrorListener: ((String) -> Unit)? = null

        private var onHighlightListener: ((Pair<Int, Int>) -> Unit)? = null

        private var customActionForDestroy: (() -> Unit)? = null

        init {
            Log.d("Init", "Init TTS")
            initTTS()
        }

        fun registerLifecycle(owner: LifecycleOwner): TextToSpeechHelper {
            owner.lifecycle.addObserver(this)
            return this
        }

        private fun initTTS() =
            context.get()?.run {
                ttsEngine =
                    TextToSpeechEngine.getInstance()
                        .setOnCompletionListener { onDoneListener?.invoke() }
                        .setOnErrorListener { onErrorListener?.invoke(it) }
                        .setOnStartListener { onStart?.invoke() }
            }

        fun speak(message: String): TextToSpeechHelper {
            if (ttsEngine == null) {
                initTTS()
            }
            this.message = message

            ttsEngine?.initTTS(
                appContext,
                message,
            )
            return this
        }

        /**
         * This method will highlight the text in the textView
         *
         * @exception Exception("Message can't be null for highlighting !! Call speak() first")
         */
        fun highlight(): TextToSpeechHelper {
            if (message == null) {
                throw Exception("Message can't be null for highlighting !! Call speak() first")
            }
            ttsEngine?.setHighlightedMessage(message!!)
            ttsEngine?.setOnHighlightListener { i, i2 -> onHighlightListener?.invoke(Pair(i, i2)) }
            return this
        }

        fun removeHighlight(): TextToSpeechHelper {
            message = null
            onHighlightListener = null
            return this
        }

        fun destroy(action: (() -> Unit) = {}) {
            ttsEngine?.destroy()
            ttsEngine = null
            action.invoke()
            instance = null
        }

        fun onStart(onStartListener: () -> Unit): TextToSpeechHelper {
            this.onStart = onStartListener
            return this
        }

        fun onDone(onCompleteListener: () -> Unit): TextToSpeechHelper {
            this.onDoneListener = onCompleteListener
            return this
        }

        fun onError(onErrorListener: (String) -> Unit): TextToSpeechHelper {
            this.onErrorListener = onErrorListener
            return this
        }

        fun onHighlight(onHighlightListener: (Pair<Int, Int>) -> Unit): TextToSpeechHelper {
            this.onHighlightListener = onHighlightListener
            return this
        }

        fun setCustomActionForDestroy(action: () -> Unit): TextToSpeechHelper {
            customActionForDestroy = action
            return this
        }

        fun setLanguage(locale: Locale): TextToSpeechHelper {
            ttsEngine?.setLanguage(locale)
            return this
        }

        fun setPitchAndSpeed(
            pitch: Float = DEF_SPEECH_AND_PITCH,
            speed: Float = DEF_SPEECH_AND_PITCH,
        ): TextToSpeechHelper {
            ttsEngine?.setPitchAndSpeed(pitch, speed)
            return this
        }

        fun resetPitchAndSpeed(): TextToSpeechHelper {
            ttsEngine?.resetPitchAndSpeed()
            return this
        }

        companion object {
            private var instance: TextToSpeechHelper? = null

            fun getInstance(context: Context): TextToSpeechHelper {
                synchronized(TextToSpeechHelper::class.java) {
                    if (instance == null) {
                        instance = TextToSpeechHelper(WeakReference(context))
                    }
                    return instance!!
                }
            }
        }

        override fun onStateChanged(
            source: LifecycleOwner,
            event: Lifecycle.Event,
        ) {
            if (
                event == Lifecycle.Event.ON_DESTROY ||
                event == Lifecycle.Event.ON_STOP ||
                event == Lifecycle.Event.ON_PAUSE
            ) {
                destroy { customActionForDestroy?.invoke() }
            }
        }
    }