package io.oxygenhub.android.ui.inbox

import androidx.compose.foundation.clickable

import androidx.compose.foundation.layout.Box

import androidx.compose.foundation.layout.fillMaxSize

import androidx.compose.foundation.layout.size

import androidx.compose.foundation.lazy.LazyColumn

import androidx.compose.foundation.lazy.items

import androidx.compose.foundation.shape.CircleShape

import androidx.compose.material.icons.Icons

import androidx.compose.material.icons.automirrored.outlined.CallMerge

import androidx.compose.material.icons.outlined.AlternateEmail

import androidx.compose.material.icons.outlined.Backup

import androidx.compose.material.icons.outlined.BugReport

import androidx.compose.material.icons.outlined.ChatBubbleOutline

import androidx.compose.material.icons.outlined.DoneAll

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

import androidx.compose.material.icons.outlined.Notifications

import androidx.compose.material.icons.outlined.PlayCircle

import androidx.compose.material.icons.outlined.RateReview

import androidx.compose.material3.HorizontalDivider

import androidx.compose.material3.Icon

import androidx.compose.material3.IconButton

import androidx.compose.material3.ListItem

import androidx.compose.material3.ListItemDefaults

import androidx.compose.material3.MaterialTheme

import androidx.compose.material3.SnackbarHostState

import androidx.compose.material3.Surface

import androidx.compose.material3.Text

import androidx.compose.runtime.Composable

import androidx.compose.runtime.LaunchedEffect

import androidx.compose.runtime.getValue

import androidx.compose.runtime.remember

import androidx.compose.ui.Alignment

import androidx.compose.ui.Modifier

import androidx.compose.ui.graphics.vector.ImageVector

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

import androidx.compose.ui.text.style.TextOverflow

import androidx.compose.ui.unit.dp

import androidx.lifecycle.compose.collectAsStateWithLifecycle

import io.oxygenhub.android.api.Notification

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

import io.oxygenhub.android.ui.common.EmptyState

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

import io.oxygenhub.android.ui.common.relativeTime

import io.oxygenhub.android.ui.theme.Tones

/**

 * The inbox. A notification opens what it is about on its own screen in

 * the app ([onOpen]): an issue, proposal, run, change, file or board; the

 * browser only for a page the app does not show.

 */

@Composable

fun InboxScreen(vm: InboxViewModel, onOpen: (url: String) -> Unit) {

    val state by vm.state.collectAsStateWithLifecycle()

    val message by vm.message.collectAsStateWithLifecycle()

    val snackbar = remember { SnackbarHostState() }

    LaunchedEffect(message) {

        message?.let {

            snackbar.showSnackbar(it)

            vm.messageShown()

        }

    }

    val unread = state.valueOrNull?.unread ?: 0

    AppScreen(

        title = "Inbox",

        subtitle = if (unread > 0) "$unread unread" else null,

        snackbar = snackbar,

        actions = {

            if (unread > 0) {

                IconButton(onClick = vm::markAllRead) { Icon(Icons.Outlined.DoneAll, contentDescription = "Mark all read") }

            }

        },

    ) {

        LoadContent(state, onRefresh = vm::refresh) { inbox ->

            if (inbox.items.isEmpty()) {

                EmptyState(Icons.Outlined.Inbox, "Your inbox is empty", "Mentions, reviews and activity on what you watch arrive here.")

            } else {

                LazyColumn(Modifier.fillMaxSize()) {

                    items(inbox.items, key = { it.id }) { n ->

                        NotificationRow(n, onClick = {

                            vm.markRead(n)

                            if (n.url.isNotBlank()) onOpen(n.url)

                        })

                        HorizontalDivider()

                    }

                }

            }

        }

    }

}

@Composable

fun NotificationRow(n: Notification, onClick: () -> Unit) {

    ListItem(

        modifier = Modifier.clickable(onClick = onClick),

        colors = if (n.read) ListItemDefaults.colors() else ListItemDefaults.colors(containerColor = MaterialTheme.colorScheme.surfaceContainerHigh),

        leadingContent = {

            Box(contentAlignment = Alignment.TopEnd) {

                Icon(iconFor(n.kind), contentDescription = null, tint = Tones.of(n.kind))

                if (!n.read) {

                    Surface(Modifier.size(8.dp), shape = CircleShape, color = MaterialTheme.colorScheme.primary) {}

                }

            }

        },

        headlineContent = {

            Text(n.title, maxLines = 2, overflow = TextOverflow.Ellipsis, fontWeight = if (n.read) FontWeight.Normal else FontWeight.SemiBold)

        },

        supportingContent = {

            val who = if (n.actor.isNotBlank()) "${n.actor} · " else ""

            Text("$who${describe(n.kind)} · ${relativeTime(n.atMs)}", maxLines = 1, overflow = TextOverflow.Ellipsis)

        },

    )

}

private fun iconFor(kind: String): ImageVector = when {

    kind == "mention" -> Icons.Outlined.AlternateEmail

    kind.startsWith("proposal.review") -> Icons.Outlined.RateReview

    kind.endsWith(".comment") -> Icons.Outlined.ChatBubbleOutline

    kind.startsWith("proposal") -> Icons.AutoMirrored.Outlined.CallMerge

    kind.startsWith("issue") -> Icons.Outlined.BugReport

    kind.startsWith("flow") -> Icons.Outlined.PlayCircle

    kind.startsWith("backup") -> Icons.Outlined.Backup

    else -> Icons.Outlined.Notifications

}

/**

 * What a kind of notification is called, as the hub's emails name them

 * (oxygenhub crates/hub/src/notify/mod.rs, `label`), without the emoji.

 */

internal fun describe(kind: String): String = when (kind) {

    "flow.failed" -> "Build broken"

    "flow.fixed" -> "Build fixed"

    "flow.runner_drained" -> "Runner drained"

    "backup" -> "Backup failed"

    "backup.recovered" -> "Backup recovered"

    "backup.summary" -> "Daily backup summary"

    "proposal.opened" -> "New proposal"

    "proposal.review_requested" -> "Review requested"

    "proposal.review" -> "New review"

    "proposal.landed" -> "Proposal landed"

    "proposal.comment", "issue.comment", "drop.comment" -> "New comment"

    "issue.opened" -> "New issue"

    "issue.assigned" -> "Issue assigned"

    "issue.closed" -> "Issue closed"

    "account.registered" -> "New sign-up"

    "mention" -> "Mentioned you"

    else -> kind.replace('.', ' ').replace('_', ' ').replaceFirstChar { it.uppercase() }

}