package soy.iko.opencode.ui.chat

import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Row
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.heightIn
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.size
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.items
import androidx.compose.foundation.text.KeyboardActions
import androidx.compose.foundation.text.KeyboardOptions
import androidx.compose.material.icons.Icons
import androidx.compose.material.icons.filled.Check
import androidx.compose.material.icons.filled.Search
import androidx.compose.material3.CircularProgressIndicator
import androidx.compose.material3.ExperimentalMaterial3Api
import androidx.compose.material3.Icon
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.ModalBottomSheet
import androidx.compose.material3.OutlinedTextField
import androidx.compose.material3.Text
import androidx.compose.material3.TextButton
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.saveable.rememberSaveable
import androidx.compose.runtime.setValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.platform.LocalSoftwareKeyboardController
import androidx.compose.ui.res.stringResource
import androidx.compose.ui.semantics.Role
import androidx.compose.ui.semantics.contentDescription
import androidx.compose.ui.semantics.role
import androidx.compose.ui.semantics.selected
import androidx.compose.ui.semantics.semantics
import androidx.compose.ui.text.input.ImeAction
import androidx.compose.ui.unit.dp
import androidx.compose.foundation.layout.Box
import soy.iko.opencode.data.model.ModelOption
import soy.iko.opencode.R

/** Bottom sheet that lists every provider/model and lets the user pick one. */
@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun ModelPickerSheet(
    options: List<ModelOption>,
    selected: ModelOption?,
    loading: Boolean,
    error: Boolean,
    onSelect: (ModelOption) -> Unit,
    onRetry: () -> Unit,
    onDismiss: () -> Unit,
) {
    ModalBottomSheet(onDismissRequest = onDismiss) {
        Text(
            stringResource(R.string.model),
            style = MaterialTheme.typography.titleMedium,
            modifier = Modifier.padding(start = 24.dp, end = 24.dp, bottom = 8.dp),
        )
        if (loading) {
            val loadingLabel = stringResource(R.string.loading)
            Box(
                modifier = Modifier.fillMaxWidth().padding(vertical = 24.dp),
                contentAlignment = Alignment.Center,
            ) {
                CircularProgressIndicator(Modifier.semantics { contentDescription = loadingLabel })
            }
        } else if (error && options.isEmpty()) {
            Column(
                modifier = Modifier.fillMaxWidth().padding(horizontal = 24.dp, vertical = 16.dp),
                horizontalAlignment = Alignment.CenterHorizontally,
            ) {
                Text(
                    stringResource(R.string.load_failed),
                    style = MaterialTheme.typography.bodyMedium,
                    color = MaterialTheme.colorScheme.error,
                )
                TextButton(onClick = onRetry) { Text(stringResource(R.string.retry)) }
            }
        } else if (options.isEmpty()) {
            Text(
                stringResource(R.string.no_models),
                style = MaterialTheme.typography.bodyMedium,
                color = MaterialTheme.colorScheme.onSurfaceVariant,
                modifier = Modifier.padding(horizontal = 24.dp, vertical = 16.dp),
            )
        } else {
            var query by rememberSaveable { mutableStateOf("") }
            val keyboardController = LocalSoftwareKeyboardController.current
            OutlinedTextField(
                value = query,
                onValueChange = { query = it },
                modifier = Modifier.fillMaxWidth().padding(horizontal = 24.dp, vertical = 8.dp),
                placeholder = { Text(stringResource(R.string.search_models)) },
                leadingIcon = { Icon(Icons.Filled.Search, contentDescription = null) },
                singleLine = true,
                keyboardOptions = KeyboardOptions(imeAction = ImeAction.Search),
                keyboardActions = KeyboardActions(onSearch = { keyboardController?.hide() }),
            )
            val filtered = remember(options, query) {
                val q = query.trim()
                if (q.isEmpty()) options
                else options.filter {
                    it.modelLabel.contains(q, ignoreCase = true) ||
                        it.providerLabel.contains(q, ignoreCase = true)
                }
            }
            if (filtered.isEmpty()) {
                Text(
                    stringResource(R.string.no_models_match, query.trim()),
                    style = MaterialTheme.typography.bodyMedium,
                    color = MaterialTheme.colorScheme.onSurfaceVariant,
                    modifier = Modifier.padding(horizontal = 24.dp, vertical = 16.dp),
                )
            } else {
                // Group by provider so a long catalog is scannable: a provider header
                // followed by its models, instead of a flat list mixing providers.
                val grouped = remember(filtered) { filtered.groupBy { it.providerID } }
                LazyColumn(modifier = Modifier.fillMaxWidth().heightIn(max = 420.dp)) {
                    grouped.forEach { (providerID, opts) ->
                        item(key = "header_$providerID") {
                            Text(
                                opts.firstOrNull()?.providerLabel ?: providerID,
                                style = MaterialTheme.typography.labelMedium,
                                color = MaterialTheme.colorScheme.primary,
                                modifier = Modifier.padding(start = 24.dp, top = 12.dp, bottom = 4.dp),
                            )
                        }
                        items(opts, key = { it.providerID to it.modelID }) { option ->
                    val isSelected = option.providerID == selected?.providerID &&
                        option.modelID == selected?.modelID
                    Column(
                        modifier = Modifier
                            .fillMaxWidth()
                            .semantics(mergeDescendants = true) {
                                if (isSelected) this.selected = true
                            }
                            .clickable(role = Role.RadioButton) {
                                onSelect(option)
                                onDismiss()
                            }
                            .padding(horizontal = 24.dp, vertical = 12.dp),
                    ) {
                        Row(verticalAlignment = Alignment.CenterVertically) {
                            Text(
                                option.modelLabel,
                                style = MaterialTheme.typography.bodyLarge,
                                color = if (isSelected) MaterialTheme.colorScheme.primary else MaterialTheme.colorScheme.onSurface,
                                modifier = Modifier.weight(1f),
                            )
                            if (isSelected) {
                                Icon(
                                    Icons.Filled.Check,
                                    contentDescription = null,
                                    tint = MaterialTheme.colorScheme.primary,
                                    modifier = Modifier.size(18.dp),
                                )
                            }
                        }
                    }
                }
                    }
            }
        }
        }
    }
}