package com.peachpasswords.ui.updates

import androidx.activity.compose.BackHandler
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.systemBarsPadding
import androidx.compose.foundation.rememberScrollState
import androidx.compose.foundation.verticalScroll
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.remember
import androidx.compose.ui.Modifier
import androidx.hilt.navigation.compose.hiltViewModel
import com.peachpasswords.ui.theme.PeachSpacing
import com.peachpasswords.ui.theme.PeachType
import com.peachpasswords.ui.theme.ShellBackground
import com.peachpasswords.ui.theme.peachColors

/**
 * Shown once, after an update, for the version now running. The gate is a stored
 * "last seen changelog version" compared against this build — so it appears on the
 * first launch of a new version and never again, and never at all on a fresh
 * install (there is nothing to catch up on).
 */
@Composable
fun WhatsNewScreen(
    onDone: () -> Unit,
    vm: UpdateViewModel = hiltViewModel(),
) {
    // Snapshotted, not collected: dismissing clears the flow, and a live read would
    // blank the text out from under the exit animation.
    val notes = remember { vm.whatsNew.value.orEmpty() }

    fun finish() {
        vm.dismissWhatsNew()
        onDone()
    }
    BackHandler { finish() }

    ShellBackground {
        Column(
            Modifier
                .fillMaxSize()
                .systemBarsPadding()
                .padding(horizontal = PeachSpacing.lg, vertical = PeachSpacing.xl),
        ) {
            Text("what's new", color = peachColors.T0, style = PeachType.createHeadline)
            Spacer(Modifier.height(PeachSpacing.xs))
            Text("v${vm.currentVersion}", color = peachColors.T1, style = PeachType.labelMono)
            Spacer(Modifier.height(PeachSpacing.xl))

            Column(Modifier.weight(1f).verticalScroll(rememberScrollState())) {
                ReleaseNotes(notes)
            }

            Spacer(Modifier.height(PeachSpacing.lg))
            PrimaryButton("Continue") { finish() }
        }
    }
}