iceraven-browser/app/src/main/java/org/mozilla/fenix/settings/AccessibilityFragment.kt

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package org.mozilla.fenix.settings

import android.os.Bundle
import androidx.preference.PreferenceFragmentCompat
import androidx.preference.SwitchPreference
import org.mozilla.fenix.R
import org.mozilla.fenix.ext.components
import org.mozilla.fenix.ext.settings
import org.mozilla.fenix.ext.showToolbar

/**
 * Displays font size controls for accessibility.
 *
 * Includes an automatic font sizing toggle. When turned on, font sizing follows the Android device settings.
 * When turned off, the font sizing can be controlled manually within the app.
 */
class AccessibilityFragment : PreferenceFragmentCompat() {
    override fun onResume() {
        super.onResume()
        showToolbar(getString(R.string.preferences_accessibility))

        val forceZoomPreference = requirePreference<SwitchPreference>(
            R.string.pref_key_accessibility_force_enable_zoom
        )

        forceZoomPreference.setOnPreferenceChangeListener<Boolean> { preference, shouldForce ->
            val settings = preference.context.settings()
            val components = preference.context.components

            settings.forceEnableZoom = shouldForce
            components.core.engine.settings.forceUserScalableContent = shouldForce

            true
        }

        val textSizePreference = requirePreference<TextPercentageSeekBarPreference>(
            R.string.pref_key_accessibility_font_scale
        )
        textSizePreference.setOnPreferenceChangeListener<Int> { preference, newTextSize ->
            val settings = preference.context.settings()
            val components = preference.context.components

            // Value is mapped from 0->30 in steps of 1 so let's convert to float in range 0.5->2.0
            val newTextScale = ((newTextSize * STEP_SIZE) + MIN_SCALE_VALUE).toFloat() / PERCENT_TO_DECIMAL

            // If scale is 100%, use the automatic font size adjustment
            val useAutoSize = newTextScale == 1F
            components.core.engine.settings.automaticFontSizeAdjustment = useAutoSize
            components.core.engine.settings.fontInflationEnabled = useAutoSize

            // If using manual sizing, update the engine settings with the new scale
            if (!useAutoSize) {
                settings.fontSizeFactor = newTextScale
                components.core.engine.settings.fontSizeFactor = newTextScale
            }

            // Reload the current session to reflect the new text scale
            components.useCases.sessionUseCases.reload()
            true
        }
    }

    override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
        setPreferencesFromResource(R.xml.accessibility_preferences, rootKey)
    }

    companion object {
        const val MIN_SCALE_VALUE = 50
        const val STEP_SIZE = 5
        const val PERCENT_TO_DECIMAL = 100f
    }
}