import { useRef } from 'react';
import type { VimMotionSystem, Motion } from './types';

export function useVimMotions(): VimMotionSystem {
  const countRef = useRef<string>('');
  const lastMotionRef = useRef<Motion | null>(null);

  const processKey = (key: string) => {
    if (key >= '0' && key <= '9') {
      if (key === '0' && countRef.current === '') {
        return { type: 'anchor', data: 'start' };
      }
      countRef.current += key;
      return { type: 'count', data: key };
    }

    const count = countRef.current ? parseInt(countRef.current, 10) : 1;

    switch (key) {
      case 'h':
        const motionH = { dr: 0, dc: -1, steps: count };
        lastMotionRef.current = motionH;
        countRef.current = '';
        return { type: 'move', data: motionH };

      case 'j':
        const motionJ = { dr: 1, dc: 0, steps: count };
        lastMotionRef.current = motionJ;
        countRef.current = '';
        return { type: 'move', data: motionJ };

      case 'k':
        const motionK = { dr: -1, dc: 0, steps: count };
        lastMotionRef.current = motionK;
        countRef.current = '';
        return { type: 'move', data: motionK };

      case 'l':
        const motionL = { dr: 0, dc: 1, steps: count };
        lastMotionRef.current = motionL;
        countRef.current = '';
        return { type: 'move', data: motionL };

      case '^':
        countRef.current = '';
        return { type: 'anchor', data: 'start' };

      case '$':
        countRef.current = '';
        return { type: 'anchor', data: 'end' };

      case 'g':
        countRef.current = '';
        return { type: 'anchor', data: 'top' };

      case 'G':
        countRef.current = '';
        return { type: 'anchor', data: 'bottom' };

      case '.':
        const lastMotion = lastMotionRef.current;
        if (lastMotion) {
          return { type: 'repeat', data: lastMotion };
        }
        return null;

      case 'i':
        countRef.current = '';
        return { type: 'mode', data: 'edit' };

      case 'Escape':
        countRef.current = '';
        return { type: 'mode', data: 'normal' };

      case 'x':
      case 'Delete':
      case 'Backspace':
        countRef.current = '';
        return { type: 'erase', data: null };

      default:
        if (key >= '1' && key <= '9') {
          countRef.current = '';
          return { type: 'digit', data: key };
        }
        return null;
    }
  };

  const resetCount = () => {
    countRef.current = '';
  };

  const getCount = () => {
    return countRef.current ? parseInt(countRef.current, 10) : 1;
  };

  const hasCount = () => {
    return countRef.current !== '';
  };

  const setLastMotion = (motion: Motion) => {
    lastMotionRef.current = motion;
  };

  const repeatLastMotion = () => {
    return lastMotionRef.current;
  };

  return {
    processKey,
    resetCount,
    getCount,
    hasCount,
    setLastMotion,
    repeatLastMotion
  };
}