/* 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 mozilla.components.feature.autofill.ui

import android.content.Intent
import android.os.Build
import android.os.Bundle
import android.os.Parcel
import android.service.autofill.FillResponse
import android.view.autofill.AutofillManager
import android.widget.inline.InlinePresentationSpec
import androidx.annotation.RequiresApi
import androidx.fragment.app.FragmentActivity
import androidx.lifecycle.lifecycleScope
import kotlinx.coroutines.Deferred
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.async
import kotlinx.coroutines.runBlocking
import mozilla.components.feature.autofill.AutofillConfiguration
import mozilla.components.feature.autofill.authenticator.Authenticator
import mozilla.components.feature.autofill.authenticator.createAuthenticator
import mozilla.components.feature.autofill.facts.emitAutofillLock
import mozilla.components.feature.autofill.handler.FillRequestHandler
import mozilla.components.feature.autofill.handler.MAX_LOGINS
import mozilla.components.feature.autofill.structure.ParsedStructure

/**
 * Activity responsible for unlocking the autofill service by asking the user to verify with a
 * fingerprint or alternative device unlocking mechanism.
 */
@RequiresApi(Build.VERSION_CODES.O)
abstract class AbstractAutofillUnlockActivity : FragmentActivity() {
    abstract val configuration: AutofillConfiguration

    private var fillResponse: Deferred<FillResponse?>? = null
    private val fillHandler by lazy { FillRequestHandler(context = this, configuration) }
    private val authenticator: Authenticator? by lazy { createAuthenticator(this, configuration) }

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

        val parsedStructure = with(Parcel.obtain()) {
            val rawBytes = intent.getByteArrayExtra(EXTRA_PARSED_STRUCTURE)
            unmarshall(rawBytes!!, 0, rawBytes.size)
            setDataPosition(0)
            ParsedStructure(this).also {
                recycle()
            }
        }
        val imeSpec = intent.getImeSpec()
        val maxSuggestionCount = intent.getIntExtra(EXTRA_MAX_SUGGESTION_COUNT, MAX_LOGINS)
        // While the user is asked to authenticate, we already try to build the fill response asynchronously.
        fillResponse = lifecycleScope.async(Dispatchers.IO) {
            val builder = fillHandler.handle(parsedStructure, forceUnlock = true, maxSuggestionCount)
            val result = builder.build(this@AbstractAutofillUnlockActivity, configuration, imeSpec)
            result
        }

        if (authenticator == null) {
            // If no authenticator is available then we just bail here. Instead we should ask the user to
            // enroll, or show an error message instead.
            // https://github.com/mozilla-mobile/android-components/issues/9756
            setResult(RESULT_CANCELED)
            finish()
        } else {
            authenticator!!.prompt(this, PromptCallback())
        }
    }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        authenticator?.onActivityResult(requestCode, resultCode)
    }

    internal inner class PromptCallback : Authenticator.Callback {
        override fun onAuthenticationError() {
            fillResponse?.cancel()

            emitAutofillLock(unlocked = false)

            setResult(RESULT_CANCELED)
            finish()
        }

        override fun onAuthenticationSucceeded() {
            configuration.lock.unlock()

            val replyIntent = Intent().apply {
                // At this point it should be safe to block since the fill response should be ready once
                // the user has authenticated.
                runBlocking { putExtra(AutofillManager.EXTRA_AUTHENTICATION_RESULT, fillResponse?.await()) }
            }

            emitAutofillLock(unlocked = true)

            setResult(RESULT_OK, replyIntent)
            finish()
        }

        override fun onAuthenticationFailed() {
            setResult(RESULT_CANCELED)
            finish()
        }
    }

    companion object {
        const val EXTRA_PARSED_STRUCTURE = "parsed_structure"
        const val EXTRA_IME_SPEC = "ime_spec"
        const val EXTRA_MAX_SUGGESTION_COUNT = "max_suggestion_count"
    }
}

internal fun Intent.getImeSpec(): InlinePresentationSpec? {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
        return getParcelableExtra(AbstractAutofillUnlockActivity.EXTRA_IME_SPEC)
    } else {
        return null
    }
}
