Banksia/composeApp/src/commonMain/kotlin/moe/lava/banksia/App.kt

package moe.lava.banksia

import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.WindowInsets
import androidx.compose.foundation.layout.add
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.safeContent
import androidx.compose.foundation.layout.safeDrawing
import androidx.compose.foundation.layout.windowInsetsPadding
import androidx.compose.material3.BottomSheetScaffold
import androidx.compose.material3.ExperimentalMaterial3Api
import androidx.compose.material3.FloatingActionButton
import androidx.compose.material3.Icon
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.SheetValue
import androidx.compose.material3.rememberBottomSheetScaffoldState
import androidx.compose.material3.rememberStandardBottomSheetState
import androidx.compose.runtime.Composable
import androidx.compose.runtime.LaunchedEffect
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableFloatStateOf
import androidx.compose.runtime.mutableStateListOf
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.rememberCoroutineScope
import androidx.compose.runtime.setValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.ExperimentalComposeUiApi
import androidx.compose.ui.Modifier
import androidx.compose.ui.backhandler.PredictiveBackHandler
import androidx.compose.ui.platform.LocalDensity
import androidx.compose.ui.unit.dp
import dev.icerock.moko.geo.compose.BindLocationTrackerEffect
import dev.icerock.moko.geo.compose.LocationTrackerAccuracy
import dev.icerock.moko.geo.compose.rememberLocationTrackerFactory
import kotlinx.coroutines.flow.distinctUntilChanged
import kotlinx.coroutines.launch
import moe.lava.banksia.api.ptv.PtvService
import moe.lava.banksia.api.ptv.structures.PtvRoute
import moe.lava.banksia.api.ptv.structures.PtvStop
import moe.lava.banksia.api.ptv.structures.getProperties
import moe.lava.banksia.native.BanksiaTheme
import moe.lava.banksia.native.maps.Maps
import moe.lava.banksia.native.maps.Marker
import moe.lava.banksia.native.maps.MarkerType
import moe.lava.banksia.native.maps.Point
import moe.lava.banksia.native.maps.Polyline
import moe.lava.banksia.native.maps.getScreenHeight
import moe.lava.banksia.resources.Res
import moe.lava.banksia.resources.my_location_24
import moe.lava.banksia.ui.Searcher
import org.jetbrains.compose.resources.painterResource
import org.jetbrains.compose.ui.tooling.preview.Preview
import kotlin.coroutines.cancellation.CancellationException
import kotlin.math.roundToInt

fun buildBounds(points: List<Point>): Pair<Point, Point> {
    var north = -Double.MAX_VALUE
    var south = Double.MAX_VALUE
    var east = -Double.MAX_VALUE
    var west = Double.MAX_VALUE
    points.forEach {
        if (it.lat > north)
            north = it.lat;
        if (it.lat < south)
            south = it.lat;
        if (it.lng > east)
            east = it.lng;
        if (it.lng < west)
            west = it.lng;
    }
    return Pair(Point(north, east), Point(south, west))
}

@OptIn(ExperimentalMaterial3Api::class, ExperimentalComposeUiApi::class)
@Composable
@Preview
fun App() {
    val ptvService = remember { PtvService() }

    val scaffoldState = rememberBottomSheetScaffoldState(
        bottomSheetState = rememberStandardBottomSheetState(
            initialValue = SheetValue.PartiallyExpanded,
            skipHiddenState = false
        )
    )

    val locationFactory = rememberLocationTrackerFactory(LocationTrackerAccuracy.Best)
    val locationTracker = remember { locationFactory.createLocationTracker() }
    BindLocationTrackerEffect(locationTracker)
    var lastLocation by remember { mutableStateOf(Point(-37.8136, 144.9631)) }
    var newCameraPosition by remember {
        mutableStateOf<Pair<Point, Pair<Point, Point>?>?>(
            Pair(Point(-37.8136, 144.9631), null)
        )
    }
    var searchTextState by remember { mutableStateOf("") }
    var searchExpandedState by remember { mutableStateOf(false) }

    val sheetState = scaffoldState.bottomSheetState
    val extInsets = if (
        sheetState.currentValue != SheetValue.Hidden ||
        sheetState.targetValue != SheetValue.Hidden
    ) {
        val offset = runCatching { sheetState.requireOffset() }
        val scaffoldOffset = offset.getOrDefault(0.0f).roundToInt()
        (getScreenHeight() - scaffoldOffset - WindowInsets.safeDrawing.getBottom(LocalDensity.current)).coerceAtLeast(0)
    } else 0

    var scope = rememberCoroutineScope()
    scope.launch {
        val flow = locationTracker.getLocationsFlow()
        locationTracker.startTracking()
        flow.distinctUntilChanged().collect {
            lastLocation = Point(it.latitude, it.longitude)
        }
    }

    var route by remember { mutableStateOf<PtvRoute?>(null) }
    val polylines = remember { mutableStateListOf<Polyline>() }

    LaunchedEffect(route) {
        val route = route
        if (route == null)
            return@LaunchedEffect
        val geoRoute = ptvService.route(route.routeId, true)
        val colour = route.routeType.getProperties().colour

        val allPoints = mutableListOf<Point>()
        polylines.clear()
        geoRoute.geopath.forEach { pp ->
            // TODO: use gtfs colours
            pp.paths.forEach { sp ->
                val polyline = sp.replace(", ", ",")
                    .split(" ")
                    .map { coord ->
                        val s = coord.split(",")
                        val point = Point(s[0].toDouble(), s[1].toDouble())
                        allPoints.add(point)
                        point
                    }
                polylines.add(Polyline(polyline, colour))
            }
        }
        val bounds = buildBounds(allPoints)
        newCameraPosition = Pair(Point(0.0, 0.0), bounds)
    }

    var sheetSwipeEnabled by remember { mutableStateOf(true) }
    var peekHeight by remember { mutableStateOf(128.dp) }
    var peekHeightMultiplier by remember { mutableFloatStateOf(1F) }

    var markers by remember { mutableStateOf(listOf<Marker>()) }
    LaunchedEffect(route) { route?.let { markers = buildStops(ptvService, it) {} } }

    BanksiaTheme {
        BottomSheetScaffold(
            scaffoldState = scaffoldState,
            sheetPeekHeight = peekHeight * peekHeightMultiplier,
            modifier = Modifier.fillMaxSize(),
            sheetContent = { Box(modifier = Modifier) },
            sheetSwipeEnabled = sheetSwipeEnabled,
        ) {
            Maps(
                modifier = Modifier.fillMaxSize(),
                newCameraPosition = newCameraPosition,
                cameraPositionUpdated = { newCameraPosition = null },
                extInsets = WindowInsets(top = with(LocalDensity.current) { 56.dp.roundToPx() }, bottom = extInsets),
                markers = markers,
                polylines = polylines,
            )
            Searcher(
                ptvService = ptvService,
                expanded = searchExpandedState,
                onExpandedChange = { searchExpandedState = it },
                text = searchTextState,
                onTextChange = { searchTextState = it },
                onRouteChange = { route = it }
            )

            PredictiveBackHandler(scaffoldState.bottomSheetState.currentValue != SheetValue.Hidden) { progress ->
                sheetSwipeEnabled = false
                try {
                    progress.collect { backEvent ->
                        if (scaffoldState.bottomSheetState.currentValue == SheetValue.PartiallyExpanded) {
                            peekHeightMultiplier = 1F - backEvent.progress
                        }
                    }
                    if (scaffoldState.bottomSheetState.currentValue == SheetValue.Expanded)
                        scope.launch { scaffoldState.bottomSheetState.partialExpand() }
                    else if (scaffoldState.bottomSheetState.currentValue == SheetValue.PartiallyExpanded)
                        scope.launch {
                            scaffoldState.bottomSheetState.hide()
                            peekHeightMultiplier = 1F
                        }
                } catch (_: CancellationException) {
                    peekHeightMultiplier = 1F
                }
                sheetSwipeEnabled = true
            }

            Box(
                Modifier.windowInsetsPadding(WindowInsets.safeContent.add(WindowInsets(bottom = extInsets))),
                contentAlignment = Alignment.BottomEnd
            ) {
                FloatingActionButton(
                    containerColor = MaterialTheme.colorScheme.surfaceContainer,
                    onClick = {
                        newCameraPosition = Pair(lastLocation, null)
                    },
                ) {
                    Icon(painterResource(Res.drawable.my_location_24), "Move to current location")
                }
            }
        }
    }
}

suspend fun buildStops(
    ptvService: PtvService,
    route: PtvRoute,
    launchInfoPanel: (PtvStop) -> Unit,
): List<Marker> {
    var stops = ptvService.stopsByRoute(route.routeId, route.routeType)
    var res = mutableListOf<Marker>()
    val colour = route.routeType.getProperties().colour

    for (stop in stops) {
        if (stop.stopLatitude != null && stop.stopLongitude != null) {
            val pos = Point(stop.stopLatitude!!, stop.stopLongitude!!)

            var name = stop.stopName;
            if (name.endsWith(" Station"))
                name = name.replace(" Station", "")

            val marker = Marker(
                name = name,
                point = pos,
                type = MarkerType.GENERIC_STOP,
                colour = colour,
                onClick = {
                    launchInfoPanel(stop)
                    false
                }
            )
            res.add(marker)
        }
    }

    return res
}