package com.taskttl.presentation.onboarding


import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.pager.HorizontalPager
import androidx.compose.foundation.pager.rememberPagerState
import androidx.compose.foundation.shape.CircleShape
import androidx.compose.material3.Button
import androidx.compose.material3.ButtonDefaults
import androidx.compose.material3.Icon
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Text
import androidx.compose.material3.TextButton
import androidx.compose.runtime.Composable
import androidx.compose.runtime.LaunchedEffect
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.text.font.FontWeight
import androidx.compose.ui.text.style.TextAlign
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import com.taskttl.core.routes.Routes
import com.taskttl.data.local.model.OnboardingPage
import com.taskttl.data.state.OnboardingEvent
import com.taskttl.data.viewmodel.OnboardingViewModel
import kotlinx.coroutines.flow.collectLatest
import org.jetbrains.compose.resources.stringResource
import org.jetbrains.compose.ui.tooling.preview.Preview
import org.koin.compose.viewmodel.koinViewModel
import taskttl.composeapp.generated.resources.Res
import taskttl.composeapp.generated.resources.continue_text
import taskttl.composeapp.generated.resources.get_start_text
import taskttl.composeapp.generated.resources.skip_text

/**
 * 引导视图
 * @param [navigatorToRoute] 导航到路线
 * @param [viewModel] 视图模型
 */
@Preview
@Composable
fun OnboardingScreen(
    navigatorToRoute: (Routes) -> Unit,
    viewModel: OnboardingViewModel = koinViewModel()
) {
    val onboardingPages = OnboardingPage.entries

    val pagerState =
        rememberPagerState(0, initialPageOffsetFraction = 0f, pageCount = { onboardingPages.size })

    LaunchedEffect(Unit) {
        viewModel.events.collectLatest { event ->
            when (event) {
                is OnboardingEvent.NextPage -> {
                    pagerState.animateScrollToPage(pagerState.currentPage + 1)
                }

                is OnboardingEvent.NavMain -> {
                    navigatorToRoute(Routes.Main)
                }
            }

        }
    }
    Box(modifier = Modifier.fillMaxSize()) {
        // 右上角跳过
        TextButton(
            onClick = { viewModel.markOnboardingCompleted() },
            modifier = Modifier
                .align(Alignment.TopEnd)
                .padding(top = 32.dp, end = 16.dp)
        ) {
            Text(
                stringResource(Res.string.skip_text) + ">",
                fontSize = 16.sp,
                color = Color.Black.copy(alpha = 0.6f)
            )
        }

        Column(
            modifier = Modifier
                .fillMaxSize()
                .padding(horizontal = 30.dp, vertical = 40.dp),
            horizontalAlignment = Alignment.CenterHorizontally
        ) {
            HorizontalPager(
                state = pagerState,
                modifier = Modifier
                    .weight(1f)
                    .fillMaxWidth(),
            ) { page ->
                OnboardingPage(pageData = onboardingPages[page])
            }

            Spacer(modifier = Modifier.height(20.dp))

            // 圆点指示器
            Row(
                horizontalArrangement = Arrangement.spacedBy(8.dp),
                verticalAlignment = Alignment.CenterVertically
            ) {
                repeat(onboardingPages.size) { index ->
                    IndicatorDot(active = pagerState.currentPage == index)
                }
            }

            Spacer(modifier = Modifier.height(30.dp))

            // 底部按钮
            if (pagerState.currentPage < onboardingPages.lastIndex) {
                Button(
                    onClick = {
                        if (pagerState.currentPage < onboardingPages.lastIndex) {
                            viewModel.sendEvent(OnboardingEvent.NextPage)
                        }
                    },
                    modifier = Modifier.fillMaxWidth(),
                    colors = ButtonDefaults.buttonColors(containerColor = Color(0xFF667EEA)),
                    shape = MaterialTheme.shapes.medium
                ) {
                    Text(
                        stringResource(Res.string.continue_text),
                        color = Color.White,
                        fontSize = 18.sp
                    )
                }
            } else {
                Column(
                    modifier = Modifier.fillMaxWidth(),
                    horizontalAlignment = Alignment.CenterHorizontally
                ) {
                    Button(
                        onClick = { viewModel.markOnboardingCompleted() },
                        modifier = Modifier.fillMaxWidth(),
                        colors = ButtonDefaults.buttonColors(containerColor = Color(0xFF667EEA)),
                        shape = MaterialTheme.shapes.medium
                    ) {
                        Text(
                            stringResource(Res.string.get_start_text),
                            color = Color.White,
                            fontSize = 18.sp
                        )
                    }
                }
            }
        }
    }
}

@Composable
fun OnboardingPage(pageData: OnboardingPage) {
    Column(
        modifier = Modifier.fillMaxSize(),
        horizontalAlignment = Alignment.CenterHorizontally,
        verticalArrangement = Arrangement.Center
    ) {
        Icon(
            imageVector = pageData.icon,
            contentDescription = null,
            tint = pageData.color,
            modifier = Modifier
                .size(200.dp)
                .padding(bottom = 30.dp)
        )

        Text(
            text = stringResource(pageData.titleRes),
            fontSize = 28.sp,
            fontWeight = FontWeight.Bold,
            color = Color(0xFF333333),
            textAlign = TextAlign.Center,
            modifier = Modifier.padding(bottom = 20.dp)
        )

        Text(
            text = stringResource(pageData.descRes),
            fontSize = 16.sp,
            color = Color(0xFF666666),
            lineHeight = 24.sp,
            textAlign = TextAlign.Center,
            modifier = Modifier.padding(horizontal = 16.dp)
        )
    }
}

@Composable
fun IndicatorDot(active: Boolean) {
    Box(
        modifier = Modifier
            .size(12.dp)
            .background(
                color = if (active) Color(0xFF667EEA) else Color(0xFFDDDDDD),
                shape = CircleShape
            )
    )
}