ai-app/app/androidApp/src/main/kotlin/com/example/aiapp/MainActivity.kt

package com.example.aiapp

import android.Manifest
import android.content.Intent
import android.os.Build
import android.os.Bundle
import android.widget.Toast
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.activity.result.contract.ActivityResultContracts
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.navigationBarsPadding
import androidx.compose.foundation.layout.statusBarsPadding
import androidx.compose.foundation.text.selection.LocalTextSelectionColors
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.runtime.CompositionLocalProvider
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableIntStateOf
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.setValue
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.drawWithContent
import androidx.compose.ui.graphics.luminance
import androidx.compose.ui.layout.layout
import androidx.core.view.WindowCompat

class MainActivity : ComponentActivity() {
    // Bumped whenever enrollment lands via an aiapp:// intent so the composition below re-reads the
    // stored settings.
    private var settingsVersion by mutableIntStateOf(0)

    // The session a notification tap asked for, or null if nothing has. The serial is what makes a
    // second tap on the same session's notification a second request: without it the two compare
    // equal and the composition below has nothing to react to.
    private var openRequest by mutableStateOf<SessionOpenRequest?>(null)
    private var opens = 0

    // What another app shared into this one, for the same reason and with the same serial.
    private var shareRequest by mutableStateOf<ShareRequest?>(null)
    private var shares = 0

    // Registered up front since permission launchers must be registered before the activity reaches
    // STARTED.
    private val requestLocalNetworkPermission =
        registerForActivityResult(ActivityResultContracts.RequestPermission()) {}

    /**
     * The service starts either way, and posts nothing if this is refused.
     *
     * Deliberately not gated on the answer: the permission can be granted later from Android's own
     * settings, and a service that only ever started at the moment it was granted would stay down
     * until the app was launched again.
     */
    private val requestNotificationPermission =
        registerForActivityResult(ActivityResultContracts.RequestPermission()) {}

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

        // Before anything else that could throw, so the first crash of a launch is caught too.
        installCrashLog(this)

        // Transparent status bar on every version; the Surface below paints through underneath it
        // and content insets itself. Same reasoning as dev-updater's MainActivity.
        enableEdgeToEdge()
        // Dark status-bar icons only over a light background, decided from the scheme rather than
        // fixed. It was hardcoded to `true`, which was right against the default light surface and
        // became unreadable the moment the app wore Catppuccin Mocha.
        WindowCompat.getInsetsController(window, window.decorView).isAppearanceLightStatusBars =
            AiAppColors.background.luminance() > 0.5f

        // Android 17+ silently drops local-network traffic without this; requested up front because
        // a denial is invisible at the socket layer (it just times out).
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.CINNAMON_BUN) {
            requestLocalNetworkPermission.launch(Manifest.permission.ACCESS_LOCAL_NETWORK)
        }

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
            requestNotificationPermission.launch(Manifest.permission.POST_NOTIFICATIONS)
        }

        handleIntent(intent)
        // After enrollment, so a first launch that arrives with a token starts the service with
        // something to connect to rather than stopping it and waiting for the next launch.
        NotificationService.sync(this)

        setContent {
            // Selection colours with the theme rather than at each place text is drawn: the
            // transcript is one selection container, and a selection that ran from a reply into the
            // code block under it would otherwise change colour halfway.
            MaterialTheme(colorScheme = AiAppColors) {
                CompositionLocalProvider(LocalTextSelectionColors provides AiAppSelectionColors) {
                    Surface(modifier = Modifier.fillMaxSize()) {
                        Box(
                            modifier =
                                // Timed like the transcript times itself, and for the same reason:
                                // the frame's draw phase is where Compose's measurement lands, and
                                // a report saying "draw is high" cannot otherwise say whether the
                                // cost is the transcript or the chrome around it. The keyboard is
                                // the case that made it matter.
                                Modifier.layout { measurable, constraints ->
                                        val started = System.nanoTime()
                                        val placeable = measurable.measure(constraints)
                                        DebugStats.record(
                                            "measure: the app root",
                                            System.nanoTime() - started,
                                        )
                                        layout(placeable.width, placeable.height) {
                                            val placing = System.nanoTime()
                                            placeable.place(0, 0)
                                            DebugStats.record(
                                                "place: the app root",
                                                System.nanoTime() - placing,
                                            )
                                        }
                                    }
                                    .drawWithContent {
                                        val started = System.nanoTime()
                                        drawContent()
                                        DebugStats.record(
                                            "record: the app root",
                                            System.nanoTime() - started,
                                        )
                                    }
                                    .fillMaxSize()
                                    .statusBarsPadding()
                                    // The gesture strip at the bottom of most phones. Without it
                                    // the send row sits under the swipe area, where a tap is as
                                    // likely to navigate away as to press a button.
                                    //
                                    // No imePadding here, deliberately: applied at the root it
                                    // resizes this whole box on every frame of the keyboard
                                    // animation, which re-measures, re-places and re-records every
                                    // screen's entire tree per frame. Each screen takes the
                                    // keyboard itself, so the per-frame cost is scoped to what
                                    // actually moves.
                                    .navigationBarsPadding()
                        ) {
                            AppRoot(settingsVersion, openRequest, shareRequest)
                        }
                    }
                }
            }
        }
    }

    // launchMode="singleTop": an enrollment scan, or a notification tapped while the app is open,
    // lands here rather than in a second activity instance.
    override fun onNewIntent(intent: Intent) {
        super.onNewIntent(intent)
        handleIntent(intent)
    }

    /**
     * The one place an incoming intent is sorted into what it means.
     *
     * Three things arrive this way -- a share from another app, and an `aiapp://` URI that is
     * either an enrollment code or a notification naming a session. The URIs are told apart by host
     * rather than by two entry points, so a further kind is a branch here.
     */
    private fun handleIntent(intent: Intent?) {
        intent ?: return
        sharedContent(intent, shares + 1)?.let { shared ->
            shares = shared.serial
            shareRequest = shared
            return
        }
        val uri = intent.data ?: return
        val sessionId = notifiedSessionId(uri)
        if (sessionId != null) {
            opens++
            openRequest = SessionOpenRequest(sessionId, opens)
            return
        }
        val settings = parseEnrollmentUri(uri)
        if (settings == null) {
            Toast.makeText(this, "Not a valid enrollment code", Toast.LENGTH_LONG).show()
            return
        }
        saveServerSettings(this, settings)
        settingsVersion++
        // Enrolling is the moment there is a backend to watch, and re-enrolling elsewhere is the
        // moment the old one stops being it.
        NotificationService.sync(this)
        Toast.makeText(this, "Enrolled with ${settings.baseUrl}", Toast.LENGTH_LONG).show()
    }
}