package com.opendance.studio

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.BackHandler
import androidx.activity.compose.setContent
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Modifier
import androidx.compose.ui.platform.LocalContext
import com.opendance.studio.data.AppSettings
import com.opendance.studio.ui.AboutScreen
import com.opendance.studio.ui.ConnectScreen
import com.opendance.studio.ui.RunningScreen
import com.opendance.studio.ui.theme.OpenDanceTheme

/**
 * 应用入口与页面导航（T-AND-001 / 006 / 007 / 008）。
 *
 * 只有三个页面，用简单的状态机导航，不引入 Navigation 组件：
 *   Connect ──开始推流──▶ Running ──结束/返回──▶ Connect
 *   Connect ──关于──▶ About ──返回──▶ Connect
 */
class MainActivity : ComponentActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            OpenDanceTheme {
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colorScheme.background,
                ) {
                    OpenDanceRoot()
                }
            }
        }
    }
}

private enum class Screen { CONNECT, RUNNING, ABOUT }

@Composable
private fun OpenDanceRoot() {
    val context = LocalContext.current
    val settings = remember { AppSettings(context.applicationContext) }
    var screen by remember { mutableStateOf(Screen.CONNECT) }

    // 推流中按返回键等同于结束推流，避免相机在后台继续占用
    BackHandler(enabled = screen == Screen.RUNNING) {
        screen = Screen.CONNECT
    }

    when (screen) {
        Screen.CONNECT -> ConnectScreen(
            settings = settings,
            onStart = { screen = Screen.RUNNING },
            onAbout = { screen = Screen.ABOUT },
        )

        Screen.RUNNING -> RunningScreen(
            settings = settings,
            onStop = { screen = Screen.CONNECT },
        )

        Screen.ABOUT -> AboutScreen(
            onBack = { screen = Screen.CONNECT },
        )
    }
}