/*
 * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved.
 * SPDX-License-Identifier: GPL-3.0-only
 */

package dev.msfjarvis.aps.ui.crypto

import android.content.Intent
import android.graphics.Typeface
import android.os.Bundle
import android.text.method.PasswordTransformationMethod
import android.view.Menu
import android.view.MenuItem
import android.view.View
import androidx.activity.result.IntentSenderRequest
import androidx.activity.result.contract.ActivityResultContracts.StartIntentSenderForResult
import androidx.lifecycle.lifecycleScope
import com.github.ajalt.timberkt.e
import com.github.michaelbull.result.onFailure
import com.github.michaelbull.result.runCatching
import dev.msfjarvis.aps.R
import dev.msfjarvis.aps.databinding.DecryptLayoutBinding
import dev.msfjarvis.aps.data.password.PasswordEntry
import dev.msfjarvis.aps.util.settings.PreferenceKeys
import dev.msfjarvis.aps.util.extensions.viewBinding
import java.io.ByteArrayOutputStream
import java.io.File
import kotlin.time.ExperimentalTime
import kotlin.time.seconds
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.delay
import kotlinx.coroutines.launch
import kotlinx.coroutines.withContext
import me.msfjarvis.openpgpktx.util.OpenPgpApi
import me.msfjarvis.openpgpktx.util.OpenPgpServiceConnection
import org.openintents.openpgp.IOpenPgpService2

class DecryptActivity : BasePgpActivity(), OpenPgpServiceConnection.OnBound {

    private val binding by viewBinding(DecryptLayoutBinding::inflate)

    private val relativeParentPath by lazy(LazyThreadSafetyMode.NONE) { getParentPath(fullPath, repoPath) }
    private var passwordEntry: PasswordEntry? = null

    private val userInteractionRequiredResult = registerForActivityResult(StartIntentSenderForResult()) { result ->
        if (result.data == null) {
            setResult(RESULT_CANCELED, null)
            finish()
            return@registerForActivityResult
        }

        when (result.resultCode) {
            RESULT_OK -> decryptAndVerify(result.data)
            RESULT_CANCELED -> {
                setResult(RESULT_CANCELED, result.data)
                finish()
            }
        }
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        bindToOpenKeychain(this)
        title = name
        with(binding) {
            setContentView(root)
            passwordCategory.text = relativeParentPath
            passwordFile.text = name
            passwordFile.setOnLongClickListener {
                copyTextToClipboard(name)
                true
            }
            passwordLastChanged.run {
                runCatching {
                    text = resources.getString(R.string.last_changed, lastChangedString)
                }.onFailure {
                    visibility = View.GONE
                }
            }
        }
    }

    override fun onCreateOptionsMenu(menu: Menu?): Boolean {
        menuInflater.inflate(R.menu.pgp_handler, menu)
        passwordEntry?.let { entry ->
            if (menu != null) {
                menu.findItem(R.id.edit_password).isVisible = true
                if (entry.password.isNotEmpty()) {
                    menu.findItem(R.id.share_password_as_plaintext).isVisible = true
                    menu.findItem(R.id.copy_password).isVisible = true
                }
            }
        }
        return true
    }

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        when (item.itemId) {
            android.R.id.home -> onBackPressed()
            R.id.edit_password -> editPassword()
            R.id.share_password_as_plaintext -> shareAsPlaintext()
            R.id.copy_password -> copyPasswordToClipboard(passwordEntry?.password)
        }
        return super.onOptionsItemSelected(item)
    }

    override fun onBound(service: IOpenPgpService2) {
        super.onBound(service)
        decryptAndVerify()
    }

    override fun onError(e: Exception) {
        e(e)
    }

    /**
     * Automatically finishes the activity 60 seconds after decryption succeeded to prevent
     * information leaks from stale activities.
     */
    @OptIn(ExperimentalTime::class)
    private fun startAutoDismissTimer() {
        lifecycleScope.launch {
            delay(60.seconds)
            finish()
        }
    }

    /**
     * Edit the current password and hide all the fields populated by encrypted data so that when
     * the result triggers they can be repopulated with new data.
     */
    private fun editPassword() {
        val intent = Intent(this, PasswordCreationActivity::class.java)
        intent.putExtra("FILE_PATH", relativeParentPath)
        intent.putExtra("REPO_PATH", repoPath)
        intent.putExtra(PasswordCreationActivity.EXTRA_FILE_NAME, name)
        intent.putExtra(PasswordCreationActivity.EXTRA_PASSWORD, passwordEntry?.password)
        intent.putExtra(PasswordCreationActivity.EXTRA_EXTRA_CONTENT, passwordEntry?.extraContent)
        intent.putExtra(PasswordCreationActivity.EXTRA_EDITING, true)
        startActivity(intent)
        finish()
    }

    private fun shareAsPlaintext() {
        val sendIntent = Intent().apply {
            action = Intent.ACTION_SEND
            putExtra(Intent.EXTRA_TEXT, passwordEntry?.password)
            type = "text/plain"
        }
        // Always show a picker to give the user a chance to cancel
        startActivity(Intent.createChooser(sendIntent, resources.getText(R.string.send_plaintext_password_to)))
    }

    @OptIn(ExperimentalTime::class)
    private fun decryptAndVerify(receivedIntent: Intent? = null) {
        if (api == null) {
            bindToOpenKeychain(this)
            return
        }
        val data = receivedIntent ?: Intent()
        data.action = OpenPgpApi.ACTION_DECRYPT_VERIFY

        val inputStream = File(fullPath).inputStream()
        val outputStream = ByteArrayOutputStream()

        lifecycleScope.launch(Dispatchers.IO) {
            api?.executeApiAsync(data, inputStream, outputStream) { result ->
                when (result?.getIntExtra(OpenPgpApi.RESULT_CODE, OpenPgpApi.RESULT_CODE_ERROR)) {
                    OpenPgpApi.RESULT_CODE_SUCCESS -> {
                        startAutoDismissTimer()
                        runCatching {
                            val showPassword = settings.getBoolean(PreferenceKeys.SHOW_PASSWORD, true)
                            val showExtraContent = settings.getBoolean(PreferenceKeys.SHOW_EXTRA_CONTENT, true)
                            val monoTypeface = Typeface.createFromAsset(assets, "fonts/sourcecodepro.ttf")
                            val entry = PasswordEntry(outputStream)

                            passwordEntry = entry
                            invalidateOptionsMenu()

                            with(binding) {
                                if (entry.password.isEmpty()) {
                                    passwordTextContainer.visibility = View.GONE
                                } else {
                                    passwordTextContainer.visibility = View.VISIBLE
                                    passwordText.typeface = monoTypeface
                                    passwordText.setText(entry.password)
                                    if (!showPassword) {
                                        passwordText.transformationMethod = PasswordTransformationMethod.getInstance()
                                    }
                                    passwordTextContainer.setOnClickListener { copyPasswordToClipboard(entry.password) }
                                    passwordText.setOnClickListener { copyPasswordToClipboard(entry.password) }
                                }

                                if (entry.hasExtraContent()) {
                                    if (entry.extraContentWithoutAuthData.isNotEmpty()) {
                                        extraContentContainer.visibility = View.VISIBLE
                                        extraContent.typeface = monoTypeface
                                        extraContent.setText(entry.extraContentWithoutAuthData)
                                        if (!showExtraContent) {
                                            extraContent.transformationMethod = PasswordTransformationMethod.getInstance()
                                        }
                                        extraContentContainer.setOnClickListener { copyTextToClipboard(entry.extraContentWithoutAuthData) }
                                        extraContent.setOnClickListener { copyTextToClipboard(entry.extraContentWithoutAuthData) }
                                    }

                                    if (entry.hasUsername()) {
                                        usernameText.typeface = monoTypeface
                                        usernameText.setText(entry.username)
                                        usernameTextContainer.setEndIconOnClickListener { copyTextToClipboard(entry.username) }
                                        usernameTextContainer.visibility = View.VISIBLE
                                    } else {
                                        usernameTextContainer.visibility = View.GONE
                                    }

                                    if (entry.hasTotp()) {
                                        otpTextContainer.visibility = View.VISIBLE
                                        otpTextContainer.setEndIconOnClickListener {
                                            copyTextToClipboard(
                                                otpText.text.toString(),
                                                snackbarTextRes = R.string.clipboard_otp_copied_text
                                            )
                                        }
                                        launch(Dispatchers.IO) {
                                            // Calculate the actual remaining time for the first pass
                                            // then return to the standard 30 second affair.
                                            val remainingTime = entry.totpPeriod - (System.currentTimeMillis() % entry.totpPeriod)
                                            withContext(Dispatchers.Main) {
                                                otpText.setText(entry.calculateTotpCode()
                                                    ?: "Error")
                                            }
                                            delay(remainingTime.seconds)
                                            repeat(Int.MAX_VALUE) {
                                                val code = entry.calculateTotpCode() ?: "Error"
                                                withContext(Dispatchers.Main) {
                                                    otpText.setText(code)
                                                }
                                                delay(30.seconds)
                                            }
                                        }
                                    }
                                }
                            }

                            if (settings.getBoolean(PreferenceKeys.COPY_ON_DECRYPT, false)) {
                                copyPasswordToClipboard(entry.password)
                            }
                        }.onFailure { e ->
                            e(e)
                        }
                    }
                    OpenPgpApi.RESULT_CODE_USER_INTERACTION_REQUIRED -> {
                        val sender = getUserInteractionRequestIntent(result)
                        userInteractionRequiredResult.launch(IntentSenderRequest.Builder(sender).build())
                    }
                    OpenPgpApi.RESULT_CODE_ERROR -> handleError(result)
                }
            }
        }
    }
}