'use client';

import type { LeagueConfigFormModel } from '@/lib/types/LeagueConfigFormModel';
import { Heading } from '@/ui/Heading';
import { Icon } from '@/ui/Icon';
import { Text } from '@/ui/Text';
import { Box } from '@/ui/Box';
import { Group } from '@/ui/Group';
import { Stack } from '@/ui/Stack';
import { Surface } from '@/ui/Surface';
import { InfoFlyout } from '@/components/shared/InfoFlyout';
import { Stepper } from '@/ui/Stepper';
import { Button } from '@/ui/Button';
import { IconButton } from '@/ui/IconButton';
import { Check, HelpCircle, TrendingDown, Zap } from 'lucide-react';
import React, { useRef, useState } from 'react';

interface LeagueDropSectionProps {
  form: LeagueConfigFormModel;
  onChange?: (form: LeagueConfigFormModel) => void;
  readOnly?: boolean;
}

type DropStrategy = 'none' | 'bestNResults' | 'dropWorstN';

const DROP_OPTIONS: Array<{
  value: DropStrategy;
  label: string;
  emoji: string;
  description: string;
  defaultN?: number;
}> = [
  {
    value: 'none',
    label: 'All count',
    emoji: '✓',
    description: 'Every race counts',
  },
  {
    value: 'bestNResults',
    label: 'Best N',
    emoji: '🏆',
    description: 'Only best results',
    defaultN: 6,
  },
  {
    value: 'dropWorstN',
    label: 'Drop worst',
    emoji: '🗑️',
    description: 'Exclude worst races',
    defaultN: 2,
  },
];

export function LeagueDropSection({
  form,
  onChange,
  readOnly,
}: LeagueDropSectionProps) {
  const disabled = readOnly || !onChange;
  const dropPolicy = form.dropPolicy || { strategy: 'none' as const };
  const [showDropFlyout, setShowDropFlyout] = useState(false);
  const dropInfoRef = useRef<HTMLButtonElement>(null!);

  const handleStrategyChange = (strategy: DropStrategy) => {
    if (disabled || !onChange) return;
    
    const option = DROP_OPTIONS.find((o) => o.value === strategy);
    const next: LeagueConfigFormModel = {
      ...form,
      dropPolicy:
        strategy === 'none'
          ? {
              strategy,
            }
          : {
              strategy,
              n: dropPolicy.n ?? option?.defaultN ?? 1,
            },
    };
    onChange(next);
  };

  const handleNChange = (newValue: number) => {
    if (disabled || !onChange || dropPolicy.strategy === 'none') return;
    onChange({
      ...form,
      dropPolicy: {
        ...dropPolicy,
        n: newValue,
      },
    });
  };

  const needsN = dropPolicy.strategy !== 'none';

  return (
    <Stack gap={4}>
      {/* Section header */}
      <Group gap={3}>
        <Surface 
          display="flex" 
          width="2.5rem" 
          height="2.5rem" 
          alignItems="center" 
          justifyContent="center" 
          rounded="md" 
          bg="rgba(25, 140, 255, 0.1)"
        >
          <Icon icon={TrendingDown} size={5} intent="primary" />
        </Surface>
        <Stack flex={1} gap={0}>
          <Group gap={2}>
            <Heading level={3}>Drop Rules</Heading>
            <IconButton 
              ref={dropInfoRef} 
              icon={HelpCircle} 
              size="sm" 
              variant="ghost" 
              onClick={() => setShowDropFlyout(true)} 
              title="Help"
            />
          </Group>
          <Text size="xs" variant="low">Protect from bad races</Text>
        </Stack>
      </Group>

      <InfoFlyout
        isOpen={showDropFlyout}
        onClose={() => setShowDropFlyout(false)}
        title="Drop Rules Explained"
        anchorRef={dropInfoRef}
      >
        <Text size="xs" variant="low" block>
          Drop rules allow drivers to exclude their worst results from championship calculations.
          This protects against mechanical failures, bad luck, or occasional poor performances.
        </Text>
      </InfoFlyout>

      {/* Strategy buttons + N stepper inline */}
      <Group gap={2} wrap>
        {DROP_OPTIONS.map((option) => {
          const isSelected = dropPolicy.strategy === option.value;
          return (
            <Button
              key={option.value}
              variant={isSelected ? 'primary' : 'secondary'}
              size="sm"
              onClick={() => handleStrategyChange(option.value)}
              disabled={disabled}
            >
              <Group gap={2}>
                {isSelected && <Icon icon={Check} size={3} />}
                <Text as="span">{option.emoji}</Text>
                <Text as="span">{option.label}</Text>
              </Group>
            </Button>
          );
        })}

        {needsN && (
          <Box marginLeft={2}>
            <Stepper
              value={dropPolicy.n ?? 1}
              onChange={handleNChange}
              label="N ="
              disabled={disabled}
            />
          </Box>
        )}
      </Group>

      {/* Explanation text */}
      <Text size="xs" variant="low" block>
        {dropPolicy.strategy === 'none' && 'Every race result affects the championship standings.'}
        {dropPolicy.strategy === 'bestNResults' && `Only your best ${dropPolicy.n ?? 1} results will count.`}
        {dropPolicy.strategy === 'dropWorstN' && `Your worst ${dropPolicy.n ?? 1} results will be excluded.`}
      </Text>
    </Stack>
  );
}