package net.tinsae.clocked.components

import androidx.compose.foundation.layout.Arrangement
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.padding
import androidx.compose.foundation.layout.width
import androidx.compose.foundation.text.KeyboardOptions
import androidx.compose.material3.Button
import androidx.compose.material3.DatePicker
import androidx.compose.material3.DatePickerDialog
import androidx.compose.material3.ExperimentalMaterial3Api
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.ModalBottomSheet
import androidx.compose.material3.OutlinedTextField
import androidx.compose.material3.PrimaryTabRow
import androidx.compose.material3.Snackbar
import androidx.compose.material3.Tab
import androidx.compose.material3.Text
import androidx.compose.material3.TextButton
import androidx.compose.material3.rememberDatePickerState
import androidx.compose.material3.rememberModalBottomSheetState
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.res.stringResource
import androidx.compose.ui.text.input.KeyboardType
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import kotlinx.datetime.TimeZone
import kotlinx.datetime.toLocalDateTime
import net.tinsae.clocked.R
import net.tinsae.clocked.data.EntryType
import net.tinsae.clocked.ui.theme.ClockedTheme
import kotlin.time.Clock
import kotlin.time.Duration
import kotlin.time.Duration.Companion.minutes
import kotlin.time.Instant

@OptIn(ExperimentalMaterial3Api::class)
@Composable
fun AddLogDialog(
    onDismiss: () -> Unit,
    onSave: (timestamp: Instant, duration: Duration, reason: String?) -> Unit
) {
    val sheetState = rememberModalBottomSheetState(skipPartiallyExpanded = true)
    var hours by remember { mutableStateOf("") }
    var minutes by remember { mutableStateOf("") }
    var reason by remember { mutableStateOf("") }
    // error if submit button is clicked with mandatory values not filled (duration)
    val error = remember { mutableStateOf<String?>(null) }

    var selectedInstant by remember { mutableStateOf(Clock.System.now()) }
    var showDatePicker by remember { mutableStateOf(false) }

    // State for the new EntryType selection
    var selectedType by remember { mutableStateOf(EntryType.OVERTIME) }
    val entryTypes = listOf(EntryType.OVERTIME, EntryType.TIME_OFF)

    // Custom date formatting logic using kotlinx-datetime
    val localDateTime = selectedInstant.toLocalDateTime(TimeZone.currentSystemDefault())
    val formattedDate = "${localDateTime.month.name.take(3).lowercase().replaceFirstChar { it.uppercase() }} ${localDateTime.day}, ${localDateTime.year}"

    if (showDatePicker) {
        val datePickerState = rememberDatePickerState(initialSelectedDateMillis = selectedInstant.toEpochMilliseconds())

        DatePickerDialog(
            onDismissRequest = { showDatePicker = false },
            confirmButton = {
                TextButton(onClick = {
                    datePickerState.selectedDateMillis?.let { millis ->
                        selectedInstant = Instant.fromEpochMilliseconds(millis)
                    }
                    showDatePicker = false
                }) {
                    Text(stringResource(id = R.string.ok))
                }
            },
            dismissButton = {
                TextButton(onClick = { showDatePicker = false }) {
                    Text(stringResource(id = R.string.cancel))
                }
            }
        ) {
            DatePicker(state = datePickerState)
        }
    }

    ModalBottomSheet(
        onDismissRequest = onDismiss,
        sheetState = sheetState
    ) {
        Column(
            modifier = Modifier
                .padding(16.dp)
                .fillMaxWidth(),
            verticalArrangement = Arrangement.spacedBy(16.dp)
        ) {
            Text(
                text = stringResource(R.string.add_entry),
                style = MaterialTheme.typography.titleLarge
            )

            // Entry Type Selector
            PrimaryTabRow(selectedTabIndex = entryTypes.indexOf(selectedType)) {
                entryTypes.forEachIndexed { index, type ->
                    Tab(
                        selected = index == entryTypes.indexOf(selectedType),
                        onClick = { selectedType = type },
                        text = {
                            when(type) {
                                EntryType.OVERTIME -> Text(stringResource(R.string.overtime))
                                EntryType.TIME_OFF -> Text(stringResource(R.string.time_off))
                            }
                        }
                    )
                }
            }


            // Date Row
            Row(
                modifier = Modifier.fillMaxWidth(),
                verticalAlignment = Alignment.CenterVertically,
                horizontalArrangement = Arrangement.SpaceBetween
            ) {
                Text(stringResource(id = R.string.date), style = MaterialTheme.typography.bodyLarge)
                TextButton(
                    onClick = { showDatePicker = true },
                ) {
                    Text(formattedDate,
                        style = MaterialTheme.typography.bodyLarge)
                }
            }

            Row(
                modifier = Modifier.fillMaxWidth(),
                verticalAlignment = Alignment.CenterVertically
            ) {
                // Duration Row
                Text(
                    text = stringResource(id = R.string.duration),
                    style = MaterialTheme.typography.bodyLarge,
                )
                if (error.value != null) {
                    Text(
                        text = error.value!!,
                        color = MaterialTheme.colorScheme.error,
                        style = MaterialTheme.typography.bodyMedium,
                        modifier = Modifier.padding(start = 16.dp)
                    )
                }
            }
            Row(
                modifier = Modifier.fillMaxWidth(),
                verticalAlignment = Alignment.CenterVertically
            ) {
                OutlinedTextField(
                    value = hours,
                    onValueChange = { hours = it.filter(Char::isDigit) },
                    label = { Text(stringResource(id = R.string.hours)) },
                    keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Number),
                    modifier = Modifier.weight(0.5f)
                )
                Spacer(modifier = Modifier.width(8.dp))
                OutlinedTextField(
                    value = minutes,
                    onValueChange = {
                        val filtered = it.filter(Char::isDigit)
                        if (filtered.isEmpty() || filtered.toInt() < 60) {
                            minutes = filtered
                        }
                    },
                    label = { Text(stringResource(id = R.string.minutes)) },
                    keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Number),
                    modifier = Modifier.weight(0.5f)
                )
            }

            // Reason Field
            OutlinedTextField(
                value = reason,
                onValueChange = { reason = it },
                label = { Text(stringResource(id = R.string.reason)) },
                modifier = Modifier.fillMaxWidth()
            )

            // Action Buttons
            Row(
                modifier = Modifier.fillMaxWidth(),
                horizontalArrangement = Arrangement.End,
            ) {
                TextButton(onClick = onDismiss) {
                    Text(stringResource(id = R.string.cancel))
                }
                Spacer(modifier = Modifier.width(8.dp))
                Button(
                    onClick = {
                        if(hours.isEmpty() || minutes.isEmpty()) { // duration values cannot be empty
                            error.value = "Please enter a duration or cancel"
                            return@Button
                        }
                        // Convert hours and minutes to)
                        val h = hours.toLongOrNull() ?: 0L
                        val m = minutes.toLongOrNull() ?: 0L
                        // Use the selectedType state to determine the sign
                        val totalMinutes = if (selectedType == EntryType.OVERTIME) h * 60 + m else -(h * 60 + m)
                        val duration = totalMinutes.minutes

                        onSave(selectedInstant, duration, reason)
                    }
                ) {
                    Text(stringResource(id = R.string.save))
                }
            }
        }
    }
}
@Preview(showBackground = true)
@Composable
fun AddLogDialogPreview(){
    ClockedTheme {
        AddLogDialog(
            onDismiss = {},
            onSave = { _, _, _ -> }
        )
    }
}