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

package xyz.myachin.saveto.ui

import android.app.Activity
import android.content.Intent
import android.net.Uri
import android.os.Bundle
import android.os.Parcelable
import android.provider.DocumentsContract
import android.util.Log
import androidx.appcompat.app.AppCompatActivity
import androidx.core.content.PermissionChecker
import xyz.myachin.saveto.R
import java.io.File
import java.io.InputStream
import java.nio.file.Paths

class SharingActivity : AppCompatActivity() {
    companion object {
        const val TAG = "SharingAct"
        const val CREATE_FILE = 101
    }

    private var fromSaveScreen = false
    private var inputStream: InputStream? = null
    private var fileData: ByteArray? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        val perm = android.Manifest.permission.READ_EXTERNAL_STORAGE
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_sharing)

        if (PermissionChecker.checkSelfPermission(
                this,
                perm
            ) != PermissionChecker.PERMISSION_GRANTED
        ) {
            requestPermissions(arrayOf(perm), 110)
        }
        handleIntent(intent)
    }

    private fun handleIntent(intent: Intent?) {
        when (intent?.action) {
            Intent.ACTION_SEND -> {
                if (intent.type?.startsWith("image/") == true) {
                    handleSendImage(intent)
                }
            }
        }
    }

    private fun handleSendImage(intent: Intent) {
        (intent.getParcelableExtra<Parcelable>(Intent.EXTRA_STREAM) as? Uri)?.let {
            val createIntent = Intent(Intent.ACTION_CREATE_DOCUMENT).apply {
                type = intent.type
                addCategory(Intent.CATEGORY_OPENABLE)
                putExtra(Intent.EXTRA_TITLE, extractName(it, type!!))
                putExtra(DocumentsContract.EXTRA_INITIAL_URI, it)
            }
            inputStream = contentResolver.openInputStream(it)
            fromSaveScreen = true
            startActivityForResult(createIntent, CREATE_FILE)
        }
    }

    private fun extractName(uri: Uri, type: String): String {
        Log.d(TAG, "extractName: uri= $uri")
        Log.d(TAG, "extractName: type=$type")
        Log.d(TAG, "extractName: ${uri.lastPathSegment}")
        val typeMod = type.substringAfter("/")

        val stub = "fileName.$typeMod"
        val fn = "?filename="
        var result = when {
            uri.path == null -> stub
            uri.path!!.contains(fn) -> uri.path!!.substringAfter(fn).substringBefore("/")
            !uri.lastPathSegment.isNullOrEmpty() -> "${uri.lastPathSegment}"
            else -> stub
        }
        File(result).extension.also {
            if (it.isEmpty() || it.isBlank() || it.length > 5) {
                result = result.plus(".$typeMod")
            }
        }
        return result.replace(":", "_")
    }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        when (requestCode) {
            CREATE_FILE -> {
                when (resultCode) {
                    Activity.RESULT_CANCELED -> return
                    Activity.RESULT_OK -> {
                        readFileContent()
                        writeFile(data?.data)
                    }
                    else -> Log.wtf(TAG, "onActivityResult: result code: $resultCode")
                }
            }
        }
        finish()
    }

    override fun onResume() {
        super.onResume()
        if (!fromSaveScreen) {
            finish()
        }
    }

    private fun readFileContent() {
        fileData = inputStream?.readBytes()
        inputStream?.close()
        inputStream = null
    }

    private fun writeFile(data: Uri?) {
        if (data == null) {
            Log.e(TAG, "writeFile: Data is null")
            return
        }
        val outputStream = contentResolver.openOutputStream(data)
        outputStream?.write(fileData)
        outputStream?.close()
        fileData = null
    }
}