SaveTo/app/src/main/java/xyz/myachin/saveto/ui/MainActivity.kt

package xyz.myachin.saveto.ui

import android.Manifest
import android.content.Intent
import android.net.Uri
import android.os.Bundle
import android.view.View
import android.widget.Button
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import androidx.core.content.PermissionChecker
import xyz.myachin.saveto.R

class MainActivity : AppCompatActivity(), View.OnClickListener {
    companion object {
        const val TAG = "MainAct"
        const val READ_ES_PERM = Manifest.permission.READ_EXTERNAL_STORAGE
        const val REQ_PERM = 10
    }

    private var btSaveNow: Button? = null
    private var tvReqNow: TextView? = null
    private var dv: View? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        checkPerms()
    }

    private fun checkPerms() {
        if (PermissionChecker.checkSelfPermission(
                this,
                READ_ES_PERM
            ) != PermissionChecker.PERMISSION_GRANTED
        ) {
            dv = findViewById(R.id.divider)
            tvReqNow = findViewById(R.id.tvReqNow)
            btSaveNow = findViewById(R.id.btRequestNow)
            setPermsVisible()
        }
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        when (requestCode) {
            REQ_PERM -> {
                when (grantResults[0]) {
                    PermissionChecker.PERMISSION_GRANTED -> {
                        setPermsGone()
                    }
                    PermissionChecker.PERMISSION_DENIED, PermissionChecker.PERMISSION_DENIED_APP_OP -> {
                        tvReqNow?.text = getString(R.string.tvSetPermsManual)
                        btSaveNow?.visibility = View.GONE
                        val btReqMan = findViewById<Button>(R.id.btRequestManual)
                        btReqMan.visibility = View.VISIBLE
                        btReqMan.setOnClickListener(this)
                    }
                }
            }
        }
    }

    override fun onClick(v: View?) {
        when (v?.id) {
            R.id.btRequestNow -> {
                requestPermissions(arrayOf(READ_ES_PERM), REQ_PERM)
            }
            R.id.btRequestManual -> {
                Intent().apply {
                    action = Intent.ACTION_AUTO_REVOKE_PERMISSIONS
                    data = Uri.fromParts("package", applicationContext.packageName, null)
                }.also {
                    startActivity(it)
                }
            }
        }
    }

    private fun setPermsVisible() {
        dv?.visibility = View.VISIBLE
        tvReqNow?.visibility = View.VISIBLE
        btSaveNow?.visibility = View.VISIBLE
        btSaveNow?.setOnClickListener(this)
    }

    private fun setPermsGone() {
        dv?.visibility = View.GONE
        tvReqNow?.visibility = View.GONE
        btSaveNow?.visibility = View.GONE
    }
}