import React, { useState, type FormEvent, type ChangeEvent } from 'react';
import { Search, Loader2, AlertCircle, RefreshCw } from 'lucide-react';
import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { cn } from '@/lib/utils';
import { useWeatherStore } from '@/store/weatherStore';

export function WeatherSearchForm() {
  const { isLoading, currentWeather, searchWeather, refreshWeather } = useWeatherStore();
  const [city, setCity] = useState('');
  const [inputError, setInputError] = useState('');

  const handleInputChange = (e: ChangeEvent<HTMLInputElement>) => {
    setCity(e.target.value);
    if (inputError) setInputError('');
  };

  const handleSubmit = async (e: FormEvent<HTMLFormElement>) => {
    e.preventDefault();
    const trimmed = city.trim();

    if (!trimmed) {
      setInputError('请输入城市名称');
      return;
    }
    if (trimmed.length < 2) {
      setInputError('城市名称至少需要2个字符');
      return;
    }
    if (!/^[\u4e00-\u9fa5a-zA-Z\s-]+$/.test(trimmed)) {
      setInputError('城市名称包含无效字符');
      return;
    }

    await searchWeather(trimmed);
  };

  return (
    <div className="p-6 border-b border-slate-200/50 dark:border-slate-700/50">
      <form onSubmit={handleSubmit} className="space-y-3">
        <div className="relative">
          <div className="absolute inset-y-0 left-4 flex items-center pointer-events-none">
            <Search className="w-5 h-5 text-slate-400 dark:text-slate-500" />
          </div>
          <Input
            type="text"
            value={city}
            onChange={handleInputChange}
            placeholder="搜索城市，如北京、上海、London..."
            disabled={isLoading}
            className={cn(
              'h-12 pl-12 pr-4 text-base rounded-xl',
              'bg-slate-50/50 dark:bg-slate-900/50',
              'focus:bg-white dark:focus:bg-slate-900',
              'transition-all duration-200',
              inputError && 'border-red-300 dark:border-red-700'
            )}
          />
        </div>

        {inputError && (
          <div className="flex items-start gap-2 px-3 py-2 rounded-lg bg-red-50/80 dark:bg-red-900/20 animate-in slide-in-from-top-1 fade-in">
            <AlertCircle className="w-4 h-4 text-red-500 mt-0.5" />
            <p className="text-xs text-red-600 dark:text-red-400 font-medium">{inputError}</p>
          </div>
        )}

        <div className="flex gap-2">
          <Button
            type="submit"
            disabled={isLoading || !city.trim()}
            className="flex-1 h-11 rounded-xl bg-gradient-to-r from-blue-600 to-cyan-600 hover:from-blue-700 hover:to-cyan-700 shadow-lg shadow-blue-500/30 hover:shadow-xl hover:shadow-blue-500/40 disabled:opacity-50 transition-all duration-300"
          >
            {isLoading ? (
              <>
                <Loader2 className="w-4 h-4 animate-spin" />
                <span className="ml-2">搜索中</span>
              </>
            ) : (
              <>
                <Search className="w-4 h-4" />
                <span className="ml-2">搜索</span>
              </>
            )}
          </Button>

          {currentWeather && (
            <Button
              type="button"
              variant="outline"
              onClick={refreshWeather}
              disabled={isLoading}
              className="h-11 px-4 rounded-xl"
              title="刷新数据"
            >
              <RefreshCw className={cn("w-4 h-4", isLoading && "animate-spin")} />
            </Button>
          )}
        </div>
      </form>
    </div>
  );
}