package no.naiv.meddetsamme.ui

import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.rememberScrollState
import androidx.compose.foundation.verticalScroll
import androidx.compose.material3.AlertDialog
import androidx.compose.material3.Button
import androidx.compose.material3.ExperimentalMaterial3Api
import androidx.compose.material3.Icon
import androidx.compose.material3.IconButton
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Scaffold
import androidx.compose.material3.Text
import androidx.compose.material3.TextButton
import androidx.compose.material3.TopAppBar
import androidx.compose.runtime.Composable
import androidx.compose.runtime.LaunchedEffect
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.rememberCoroutineScope
import androidx.compose.runtime.setValue
import androidx.compose.ui.Modifier
import androidx.compose.ui.platform.LocalContext
import androidx.compose.ui.res.painterResource
import androidx.compose.ui.semantics.contentDescription
import androidx.compose.ui.semantics.semantics
import androidx.compose.ui.unit.dp
import kotlinx.coroutines.launch
import no.naiv.meddetsamme.R
import no.naiv.meddetsamme.data.MedDatabase

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun ItemEditScreen(nav: Nav, itemId: Long?) {
    val context = LocalContext.current
    val db = remember { MedDatabase.get(context) }
    val scope = rememberCoroutineScope()
    val form = remember { ItemFormState() }
    var confirmDelete by remember { mutableStateOf(false) }
    var deleteBlocked by remember { mutableStateOf(false) }

    LaunchedEffect(itemId) {
        itemId?.let { id -> db.inventoryDao().getById(id)?.let(form::loadFrom) }
    }

    Scaffold(
        topBar = {
            TopAppBar(
                title = { Text(if (itemId == null) "Ny lagervare" else "Rediger lagervare") },
                navigationIcon = {
                    IconButton(onClick = { nav.pop() }) {
                        Icon(painterResource(R.drawable.ic_back), contentDescription = "Tilbake")
                    }
                },
            )
        },
    ) { padding ->
        Column(
            modifier = Modifier
                .fillMaxSize()
                .padding(padding)
                .padding(horizontal = 16.dp)
                .verticalScroll(rememberScrollState()),
            verticalArrangement = Arrangement.spacedBy(10.dp),
        ) {
            InventoryItemForm(form)

            if (form.name.isNotBlank()) {
                TextButton(
                    onClick = { context.startActivity(felleskatalogenIntent(form.name)) },
                    modifier = Modifier
                        .fillMaxWidth()
                        .semantics { contentDescription = "Slå opp ${form.name} i Felleskatalogen. Åpner nettleseren." },
                ) { Text("Slå opp i Felleskatalogen ↗") }
            }

            Button(
                onClick = {
                    val item = form.buildItem(itemId ?: 0) ?: return@Button
                    scope.launch {
                        if (itemId == null) db.inventoryDao().insert(item) else db.inventoryDao().update(item)
                        nav.pop()
                    }
                },
                modifier = Modifier.fillMaxWidth(),
            ) { Text("Lagre") }

            if (itemId != null) {
                TextButton(
                    onClick = {
                        scope.launch {
                            if (db.inventoryDao().referencingMedCount(itemId) > 0) {
                                deleteBlocked = true
                            } else {
                                confirmDelete = true
                            }
                        }
                    },
                    modifier = Modifier.fillMaxWidth(),
                ) { Text("Slett vare", color = MaterialTheme.colorScheme.error) }
            }
        }
    }

    if (deleteBlocked) {
        AlertDialog(
            onDismissRequest = { deleteBlocked = false },
            title = { Text("Varen er i bruk") },
            text = { Text("En medisin bruker denne varen. Slett eller avslutt medisinen først.") },
            confirmButton = { TextButton(onClick = { deleteBlocked = false }) { Text("OK") } },
        )
    }
    if (confirmDelete) {
        AlertDialog(
            onDismissRequest = { confirmDelete = false },
            title = { Text("Slette ${form.name.ifBlank { "varen" }}?") },
            text = { Text("Dette kan ikke angres.") },
            confirmButton = {
                TextButton(onClick = {
                    confirmDelete = false
                    scope.launch {
                        itemId?.let { db.inventoryDao().delete(it) }
                        nav.pop()
                    }
                }) { Text("Slett", color = MaterialTheme.colorScheme.error) }
            },
            dismissButton = { TextButton(onClick = { confirmDelete = false }) { Text("Avbryt") } },
        )
    }
}