Magisk/app/src/main/java/com/topjohnwu/magisk/ui/settings/BaseSettingsItem.kt

package com.topjohnwu.magisk.ui.settings

import android.content.Context
import android.content.res.Resources
import android.view.View
import androidx.annotation.CallSuper
import androidx.databinding.Bindable
import com.topjohnwu.magisk.BR
import com.topjohnwu.magisk.R
import com.topjohnwu.magisk.databinding.ObservableItem
import com.topjohnwu.magisk.utils.TextHolder
import com.topjohnwu.magisk.utils.set
import com.topjohnwu.magisk.view.MagiskDialog

sealed class BaseSettingsItem : ObservableItem<BaseSettingsItem>() {

    override val layoutRes get() = R.layout.item_settings

    open val icon: Int get() = 0
    open val title: TextHolder get() = TextHolder.EMPTY
    @get:Bindable
    open val description: TextHolder get() = TextHolder.EMPTY

    // ---

    open val showSwitch get() = false

    @get:Bindable
    open val isChecked get() = false

    open fun onToggle(view: View, callback: Callback, checked: Boolean) {}

    // ---

    @get:Bindable
    var isEnabled = true
        set(value) = set(value, field, { field = it }, BR.enabled)

    open fun onPressed(view: View, callback: Callback) {
        callback.onItemPressed(view, this)
    }

    open fun refresh() {}

    override fun itemSameAs(other: BaseSettingsItem) = this === other
    override fun contentSameAs(other: BaseSettingsItem) = itemSameAs(other)

    // ---

    interface Callback {
        fun onItemPressed(view: View, item: BaseSettingsItem, callback: () -> Unit = {})
        fun onItemChanged(view: View, item: BaseSettingsItem)
    }

    // ---

    abstract class Value<T> : BaseSettingsItem() {

        /**
         * Represents last agreed-upon value by the validation process and the user for current
         * child. Be very aware that this shouldn't be **set** unless both sides agreed that _that_
         * is the new value.
         *
         * Annotating [value] as [Bindable] property should raise red flags immediately. If you
         * need a [Bindable] property create another one. Seriously.
         * */
        abstract var value: T
            /**
             * We don't want this to be accessible to be set from outside the instances. It will
             * introduce unwanted bugs!
             * */
            protected set

        protected var callbackVars: Pair<View, Callback>? = null

        @CallSuper
        override fun onPressed(view: View, callback: Callback) {
            callbackVars = view to callback
            callback.onItemPressed(view, this) {
                onPressed(view)
            }
        }

        abstract fun onPressed(view: View)

        protected inline fun <reified T> setV(
            new: T, old: T, setter: (T) -> Unit, afterChanged: (T) -> Unit = {}) {
            set(new, old, setter, BR.description, BR.checked) {
                afterChanged(it)
                callbackVars?.let { (view, callback) ->
                    callbackVars = null
                    callback.onItemChanged(view, this)
                }
            }
        }
    }

    abstract class Toggle : Value<Boolean>() {

        override val showSwitch get() = true
        override val isChecked get() = value

        override fun onToggle(view: View, callback: Callback, checked: Boolean) =
            set(checked, value, { onPressed(view, callback) }, BR.checked)

        override fun onPressed(view: View) {
            value = !value
        }
    }

    abstract class Input : Value<String>() {

        protected abstract val inputResult: String?

        override fun onPressed(view: View) {
            MagiskDialog(view.context)
                .applyTitle(title.getText(view.resources))
                .applyView(getView(view.context))
                .applyButton(MagiskDialog.ButtonType.POSITIVE) {
                    titleRes = android.R.string.ok
                    onClick {
                        inputResult?.let { result ->
                            preventDismiss = false
                            value = result
                            it.dismiss()
                            return@onClick
                        }
                        preventDismiss = true
                    }
                }
                .applyButton(MagiskDialog.ButtonType.NEGATIVE) {
                    titleRes = android.R.string.cancel
                }
                .reveal()
        }

        abstract fun getView(context: Context): View
    }

    abstract class Selector : Value<Int>() {

        open val entryRes get() = -1
        open val descriptionRes get() = entryRes
        open fun entries(res: Resources) = res.getArrayOrEmpty(entryRes)
        open fun descriptions(res: Resources) = res.getArrayOrEmpty(descriptionRes)

        override val description = object : TextHolder() {
            override fun getText(resources: Resources): CharSequence {
                return descriptions(resources).getOrElse(value) { "" }
            }
        }

        private fun Resources.getArrayOrEmpty(id: Int): Array<String> =
            runCatching { getStringArray(id) }.getOrDefault(emptyArray())

        override fun onPressed(view: View) {
            MagiskDialog(view.context)
                .applyTitle(title.getText(view.resources))
                .applyButton(MagiskDialog.ButtonType.NEGATIVE) {
                    titleRes = android.R.string.cancel
                }
                .applyAdapter(entries(view.resources)) {
                    value = it
                }
                .reveal()
        }

    }

    abstract class Blank : BaseSettingsItem()

    abstract class Section : BaseSettingsItem() {
        override val layoutRes = R.layout.item_settings_section
    }

}