OmniCards/mobile/src/main/java/ru/omni_devel/cards/BackupActivity.kt

package ru.omni_devel.cards

import android.net.Uri
import android.os.Bundle
import android.widget.Toast
import androidx.activity.ComponentActivity
import androidx.activity.compose.LocalActivity
import androidx.activity.compose.rememberLauncherForActivityResult
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.activity.result.contract.ActivityResultContracts
import androidx.compose.foundation.layout.PaddingValues
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material3.AlertDialog
import androidx.compose.material3.Scaffold
import androidx.compose.material3.Text
import androidx.compose.material3.TextButton
import androidx.compose.runtime.Composable
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.saveable.rememberSaveable
import androidx.compose.ui.Modifier
import androidx.compose.ui.platform.LocalContext
import kotlinx.serialization.json.Json
import ru.omni_devel.cards.ui.theme.OmniCardsTheme
import androidx.compose.runtime.getValue
import androidx.compose.runtime.setValue
import androidx.compose.ui.res.stringResource

class BackupActivity : ComponentActivity() {
    private lateinit var db: DbHelper

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        enableEdgeToEdge()

        db = DbHelper(this, null)

        setContent {
            OmniCardsTheme {
                Scaffold(modifier = Modifier.fillMaxSize()) { innerPadding ->
                    BackupPage(innerPadding = innerPadding, getDbFun = {
                        return@BackupPage db
                    })
                }
            }
        }
    }
}

@Composable
fun BackupPage(innerPadding: PaddingValues, getDbFun: () -> DbHelper) {
    val context = LocalContext.current
    val activityContext = LocalActivity.current

    val showImportDialog = rememberSaveable { mutableStateOf(false) }
    var pendingUri by rememberSaveable { mutableStateOf<Uri?>(null) }

    val createBackupLauncher = rememberLauncherForActivityResult(
        contract = ActivityResultContracts.CreateDocument("application/json")
    ) { uri ->
        uri?.let {
            try {
                val jsonData = Json.encodeToString(getDbFun().getCards())

                context.contentResolver.openOutputStream(it)?.use { outputStream ->
                    outputStream.write(jsonData.toByteArray())

                    Toast.makeText(context, context.getString(R.string.backup_successfully_saved), Toast.LENGTH_SHORT).show()

                    activityContext!!.finish()
                }
            } catch (e: Exception) {
                Toast.makeText(context, context.getString(R.string.failed_to_save_backup, e), Toast.LENGTH_LONG).show()
            }
        }
    }

    val restoreFromBackupLauncher = rememberLauncherForActivityResult(
        contract = ActivityResultContracts.GetContent()
    ) { uri ->
        uri?.let {
            pendingUri = it
            showImportDialog.value = true
        }
    }

    if (showImportDialog.value) {
        AlertDialog(
            title = { Text(stringResource(R.string.ask_do_restore)) },
            text = { Text(stringResource(R.string.restore_caution)) },
            confirmButton = {
                TextButton(
                    onClick = {
                        showImportDialog.value = false

                        pendingUri?.let { uri ->
                            try {
                                context.contentResolver.openInputStream(uri)?.use { stream ->
                                    val json = stream.bufferedReader().use { it.readText() }

                                    val cards = Json.decodeFromString<List<CardInfo>>(json)

                                    val db = getDbFun()

                                    db.clearDatabase()
                                    db.addCards(cards)

                                    Toast.makeText(context, context.getString(R.string.backup_successfully_restored), Toast.LENGTH_SHORT).show()

                                    activityContext!!.finish()
                                }
                            } catch (e: Exception) {
                                Toast.makeText(context, context.getString(R.string.failed_to_restore_backup, e), Toast.LENGTH_LONG).show()
                            }
                        }
                    }
                ) {
                    Text(stringResource(R.string.yes))
                }
            },
            dismissButton = {
                TextButton(
                    onClick = {
                        showImportDialog.value = false
                    }
                ) {
                    Text(stringResource(R.string.no))
                }
            },
            onDismissRequest = { showImportDialog.value = false },
        )
    }

    Page(stringResource(R.string.backup), innerPadding) {
        FullWidthButton(
            onClick = {
                createBackupLauncher.launch("omnicards-backup.json")
            }
        ) {
            Text(stringResource(R.string.do_backup))
        }
        FullWidthButton(
            onClick = {
                restoreFromBackupLauncher.launch("application/json")
            }
        ) {
            Text(stringResource(R.string.do_restore))
        }
    }
}