import curses
from datetime import datetime

class ListAlarmsView:
    def __init__(self, storage):
        """Initialize the list alarms view"""
        self.storage = storage
        self.weekday_names = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
        self.selected_index = 0
        self.alarms = []

    def reset_state(self):
        """Reset the view state"""
        self.selected_index = 0
        self.alarms = self.storage.get_saved_alerts()

    def update_alarms(self, alarms):
        """Update the list of alarms to display."""
        self.alarms = alarms
        self.selected_index = 0

    def get_selected_alarm(self):
        """Get the currently selected alarm."""
        if 0 <= self.selected_index < len(self.alarms):
            return self.alarms[self.selected_index]
        return None

    def draw(self, stdscr):
        """Draw the list of alarms screen"""
        height, width = stdscr.getmaxyx()

        self._draw_header(stdscr, width)
        visible_range = self._calculate_visible_range(height)
        self._draw_alarm_list(stdscr, height, width, visible_range)
        self._draw_instructions(stdscr, height, width)

    def handle_input(self, key):
        """Handle user input and return the next view name or None to stay"""
        total_items = len(self.alarms) + 1  # +1 for "Add new alarm" option

        if key == 27:  # ESC
            return 'CLOCK'
        elif key in [ord('j'), curses.KEY_DOWN]:
            self.selected_index = (self.selected_index + 1) % total_items
        elif key in [ord('k'), curses.KEY_UP]:
            self.selected_index = (self.selected_index - 1) % total_items
        elif key == ord('d'):
            return self._handle_delete()
        elif key in [ord('a'), 10]:  # 'a' or Enter
            return self._handle_add_edit()

        return None

    def _calculate_visible_range(self, height):
        """Calculate the visible range for scrolling"""
        max_visible_items = height - 8  # Space for header and footer
        total_items = len(self.alarms) + 1  # +1 for "Add new alarm" option

        # Calculate scroll position
        start_idx = max(0, min(self.selected_index - max_visible_items // 2,
                             total_items - max_visible_items))
        if start_idx < 0:
            start_idx = 0
        end_idx = min(start_idx + max_visible_items, total_items)

        return (start_idx, end_idx)

    def _draw_header(self, stdscr, width):
        """Draw the header text"""
        header_text = "Alarms"
        stdscr.attron(curses.color_pair(1) | curses.A_BOLD)
        stdscr.addstr(2, self._center_x(width, header_text), header_text)
        stdscr.attroff(curses.color_pair(1) | curses.A_BOLD)

    def _draw_alarm_list(self, stdscr, height, width, visible_range):
        """Draw the list of alarms"""
        start_idx, end_idx = visible_range

        for i in range(start_idx, end_idx):
            y_pos = 4 + (i - start_idx)
            display_str = self._format_alarm_display(i)

            # Truncate if too long
            max_length = width - 6
            if len(display_str) > max_length:
                display_str = display_str[:max_length-3] + "..."

            x_pos = self._center_x(width, display_str)
            self._draw_alarm_item(stdscr, y_pos, x_pos, display_str, i == self.selected_index)

    def _format_alarm_display(self, index):
        """Format the display string for an alarm"""
        if index == len(self.alarms):
            return "Add new alarm..."

        alarm = self.alarms[index]
        time_str = alarm.get('time', 'Unknown')
        repeat_info = self._format_repeat_info(alarm)
        status = "✓" if alarm.get('enabled', True) else "✗"

        return f"{status} {time_str} {alarm.get('name', 'Unnamed')}{repeat_info}"

    def _format_repeat_info(self, alarm):
        """Format the repeat information for an alarm"""
        repeat_rule = alarm.get('repeat_rule', {})
        if not repeat_rule:
            return ""

        if repeat_rule.get('type') == 'weekly':
            days = repeat_rule.get('days', [])
            return f" (Every {', '.join(self.weekday_names[d] for d in days)})"
        elif repeat_rule.get('type') == 'once' and repeat_rule.get('date'):
            return f" (On {repeat_rule['date']})"

        return ""

    def _draw_alarm_item(self, stdscr, y_pos, x_pos, display_str, is_selected):
        """Draw a single alarm item"""
        if is_selected:
            # Draw selection brackets in green
            stdscr.attron(curses.color_pair(1))
            stdscr.addstr(y_pos, x_pos - 2, "[ ")
            stdscr.addstr(y_pos, x_pos + len(display_str), " ]")
            stdscr.attroff(curses.color_pair(1))

            # Draw text in yellow (highlighted)
            stdscr.attron(curses.color_pair(2))
            stdscr.addstr(y_pos, x_pos, display_str)
            stdscr.attroff(curses.color_pair(2))
        else:
            # Draw normal items in green
            stdscr.attron(curses.color_pair(1))
            stdscr.addstr(y_pos, x_pos, display_str)
            stdscr.attroff(curses.color_pair(1))

    def _draw_instructions(self, stdscr, height, width):
        """Draw the instructions at the bottom of the screen"""
        instructions = "j/k: Move  d: Delete  a: Add/Edit  Esc: Back"
        stdscr.attron(curses.color_pair(1))
        stdscr.addstr(height - 2, self._center_x(width, instructions), instructions)
        stdscr.attroff(curses.color_pair(1))

    def _center_x(self, width, text):
        """Calculate x coordinate to center text"""
        return width // 2 - len(text) // 2

    def _handle_delete(self):
        """Handle alarm deletion"""
        if self.selected_index < len(self.alarms):
            try:
                alarm_to_delete = self.alarms[self.selected_index]
                self.storage.remove_saved_alert(alarm_to_delete['id'])
                self.alarms = self.storage.get_saved_alerts()
                # Adjust selected item if needed
                if self.selected_index >= len(self.alarms):
                    self.selected_index = len(self.alarms)
            except Exception as e:
                # You might want to add error handling here
                pass
        return None

    def _handle_add_edit(self):
        """Handle add/edit action"""
        if self.selected_index == len(self.alarms):
            # "Add new alarm" option selected
            return 'ADD_ALARM'
        else:
            # Edit existing alarm
            selected_alarm = self.alarms[self.selected_index]
            return ('ADD_ALARM', selected_alarm)  # Pass alarm to AddAlarmView