"""
Navigation and input handling for the TUI
"""

import curses
from typing import List
from ..models import FlowStats


class NavigationHandler:
    """Handles navigation and input for the TUI"""
    
    def __init__(self):
        self.current_view = 'main'  # main, dissection
        self.selected_flow = 0
        self.scroll_offset = 0
        self.show_timeline = True  # Toggle for bottom timeline plot
    
    def handle_input(self, key: int, flows_list: List[FlowStats]) -> str:
        """
        Handle keyboard input and return action
        
        Returns:
            Action string: 'quit', 'view_change', 'selection_change', 'none'
        """
        if key == ord('q'):
            return 'quit'
        elif key == ord('d'):
            self.current_view = 'dissection'
            return 'view_change'
        elif key == ord('m') or key == 27:  # 'm' or ESC to return to main
            self.current_view = 'main'
            return 'view_change'
        elif key == curses.KEY_UP and self.current_view == 'main':
            self.selected_flow = max(0, self.selected_flow - 1)
            return 'selection_change'
        elif key == curses.KEY_DOWN and self.current_view == 'main':
            max_items = self._get_total_display_items(flows_list)
            self.selected_flow = min(max_items - 1, self.selected_flow + 1)
            return 'selection_change'
        elif key == ord('t'):  # Toggle timeline plot
            self.show_timeline = not self.show_timeline
            return 'view_change'
        elif key == curses.KEY_PPAGE and self.current_view == 'main':  # Page Up
            self.selected_flow = max(0, self.selected_flow - 10)
            return 'selection_change'
        elif key == curses.KEY_NPAGE and self.current_view == 'main':  # Page Down
            max_items = self._get_total_display_items(flows_list)
            self.selected_flow = min(max_items - 1, self.selected_flow + 10)
            return 'selection_change'
        elif key == curses.KEY_HOME and self.current_view == 'main':  # Home
            self.selected_flow = 0
            return 'selection_change'
        elif key == curses.KEY_END and self.current_view == 'main':  # End
            max_items = self._get_total_display_items(flows_list)
            self.selected_flow = max_items - 1
            return 'selection_change'
        
        return 'none'
    
    def _get_total_display_items(self, flows_list: List[FlowStats]) -> int:
        """Calculate total number of selectable items (flows + frame types)"""
        total = 0
        for flow in flows_list:
            total += 1  # Flow itself
            total += len(flow.frame_types)  # Frame types under this flow
        return total
    
    def get_status_bar_text(self) -> str:
        """Get status bar text based on current view"""
        if self.current_view == 'main':
            timeline_status = "ON" if self.show_timeline else "OFF"
            return f"[↑↓]navigate [PgUp/PgDn]scroll [t]imeline:{timeline_status} [d]issection [q]uit"
        elif self.current_view == 'dissection':
            return "[m]ain view [q]uit"
        else:
            return "[m]ain [d]issection [q]uit"