package io.oxygenhub.android.ui.dashboard

import androidx.compose.foundation.clickable

import androidx.compose.foundation.layout.Arrangement

import androidx.compose.foundation.layout.BoxWithConstraints

import androidx.compose.foundation.layout.Column

import androidx.compose.foundation.layout.Row

import androidx.compose.foundation.layout.Spacer

import androidx.compose.foundation.layout.fillMaxWidth

import androidx.compose.foundation.layout.height

import androidx.compose.foundation.layout.padding

import androidx.compose.foundation.rememberScrollState

import androidx.compose.foundation.verticalScroll

import androidx.compose.material.icons.Icons

import androidx.compose.material.icons.outlined.Inbox

import androidx.compose.material.icons.outlined.MarkEmailUnread

import androidx.compose.material3.Card

import androidx.compose.material3.HorizontalDivider

import androidx.compose.material3.Icon

import androidx.compose.material3.ListItem

import androidx.compose.material3.ListItemDefaults

import androidx.compose.material3.MaterialTheme

import androidx.compose.material3.Text

import androidx.compose.material3.TextButton

import androidx.compose.runtime.Composable

import androidx.compose.runtime.getValue

import androidx.compose.ui.Modifier

import androidx.compose.ui.graphics.Color

import androidx.compose.ui.text.font.FontWeight

import androidx.compose.ui.unit.dp

import androidx.lifecycle.compose.collectAsStateWithLifecycle

import io.oxygenhub.android.api.Inbox

import io.oxygenhub.android.api.Repository

import io.oxygenhub.android.ui.common.AppScreen

import io.oxygenhub.android.ui.common.Load

import io.oxygenhub.android.ui.common.LoadContent

import io.oxygenhub.android.ui.repos.RepositoryRow

@Composable

fun DashboardScreen(

    vm: DashboardViewModel,

    hub: String,

    inbox: Load<Inbox>,

    onRefreshInbox: () -> Unit,

    onOpenRepository: (Repository) -> Unit,

    onAllRepositories: () -> Unit,

    onInbox: () -> Unit,

) {

    val state by vm.state.collectAsStateWithLifecycle()

    AppScreen(title = "Dashboard", subtitle = hub.substringAfter("://")) {

        LoadContent(state, onRefresh = { vm.refresh(); onRefreshInbox() }) { d ->

            DashboardContent(d, inbox, onOpenRepository, onAllRepositories, onInbox)

        }

    }

}

@Composable

fun DashboardContent(

    d: Dashboard,

    inbox: Load<Inbox>,

    onOpenRepository: (Repository) -> Unit,

    onAllRepositories: () -> Unit,

    onInbox: () -> Unit,

) {

    BoxWithConstraints {

        // Side by side once there is room (a tablet, or a foldable open).

        val wide = maxWidth >= 720.dp

        Column(

            Modifier

                .fillMaxWidth()

                .verticalScroll(rememberScrollState())

                .padding(16.dp),

        ) {

            Text(d.greeting, style = MaterialTheme.typography.headlineMedium, fontWeight = FontWeight.Bold)

            Spacer(Modifier.height(16.dp))

            if (wide) {

                Row(horizontalArrangement = Arrangement.spacedBy(16.dp)) {

                    Column(Modifier.weight(2f)) { Recent(d, onOpenRepository, onAllRepositories) }

                    Column(Modifier.weight(1f)) { Unread(inbox, onInbox) }

                }

            } else {

                Unread(inbox, onInbox)

                Spacer(Modifier.height(16.dp))

                Recent(d, onOpenRepository, onAllRepositories)

            }

        }

    }

}

@Composable

private fun Unread(inbox: Load<Inbox>, onInbox: () -> Unit) {

    Card(Modifier.fillMaxWidth().clickable(onClick = onInbox)) {

        ListItem(

            colors = ListItemDefaults.colors(containerColor = Color.Transparent),

            leadingContent = {

                Icon(if ((inbox.valueOrNull?.unread ?: 0) > 0) Icons.Outlined.MarkEmailUnread else Icons.Outlined.Inbox, contentDescription = null)

            },

            headlineContent = {

                Text(

                    when (inbox) {

                        Load.Loading -> "Inbox"

                        is Load.Failed -> "Inbox unavailable"

                        is Load.Ready -> when (val n = inbox.value.unread) {

                            0L -> "Nothing unread"

                            1L -> "1 unread notification"

                            else -> "$n unread notifications"

                        }

                    },

                )

            },

            supportingContent = (inbox as? Load.Failed)?.let { f -> { Text(f.message) } },

        )

    }

}

@Composable

private fun Recent(d: Dashboard, onOpenRepository: (Repository) -> Unit, onAllRepositories: () -> Unit) {

    Card(Modifier.fillMaxWidth()) {

        Text(

            if (d.recentAreYours) "Your recent repositories" else "Recently updated on the hub",

            style = MaterialTheme.typography.titleMedium,

            modifier = Modifier.padding(start = 16.dp, top = 16.dp, end = 16.dp),

        )

        if (!d.recentAreYours) {

            Text(

                "You have no repositories of your own yet.",

                style = MaterialTheme.typography.bodySmall,

                color = MaterialTheme.colorScheme.onSurfaceVariant,

                modifier = Modifier.padding(horizontal = 16.dp),

            )

        }

        if (d.recent.isEmpty()) {

            Text("No repositories to show.", modifier = Modifier.padding(16.dp))

        }

        d.recent.forEachIndexed { i, repo ->

            if (i > 0) HorizontalDivider()

            RepositoryRow(repo, onClick = { onOpenRepository(repo) })

        }

        TextButton(onClick = onAllRepositories, modifier = Modifier.padding(8.dp)) { Text("All repositories") }

    }

}