import { h } from 'preact';
import { useEffect, useState } from 'preact/hooks';
import modalStyles from '@lib/ui/Modal.module.css';
import styles from './GameSetupModal.module.css';
import { Button } from '@lib/ui/Button';
import { GAME_TYPES, RACE_TO_INFINITY, RACE_TO_QUICK_PICKS } from '@lib/domain/constants';
import { gameToSetupData } from '@lib/domain/gameUtils';
import { validateGameSetupData } from '@lib/domain/validation';
import type { BreakRule, GameSetupData, GameType, StandardGame } from '@lib/domain/types';

interface GameSetupModalProps {
  game: StandardGame;
  open: boolean;
  onSave: (setupData: GameSetupData) => void;
  onCancel: () => void;
}

type RaceToState = number | typeof RACE_TO_INFINITY;

interface FormState {
  player1: string;
  player2: string;
  player3: string;
  hasPlayer3: boolean;
  score1: number;
  score2: number;
  score3: number;
  gameType: GameType;
  raceTo: RaceToState;
  raceToInput: string;
  breakRule: BreakRule;
  breakOrder: number[];
  currentBreakerIdx: number;
}

function setupToFormState(setup: GameSetupData): FormState {
  const hasPlayer3 = Boolean(setup.player3?.trim());
  const raceToIsInfinity = setup.raceTo === Infinity;
  return {
    player1: setup.player1,
    player2: setup.player2,
    player3: setup.player3 ?? '',
    hasPlayer3,
    score1: setup.score1,
    score2: setup.score2,
    score3: setup.score3 ?? 0,
    gameType: setup.gameType,
    raceTo: raceToIsInfinity ? RACE_TO_INFINITY : setup.raceTo,
    raceToInput: raceToIsInfinity ? '' : String(setup.raceTo),
    breakRule: setup.breakRule,
    breakOrder: [...setup.breakOrder],
    currentBreakerIdx: setup.currentBreakerIdx,
  };
}

function parseRaceToValue(raceTo: RaceToState, raceToInput: string): number {
  if (raceTo === RACE_TO_INFINITY) return Infinity;
  if (typeof raceTo === 'number' && Number.isFinite(raceTo)) return raceTo;
  const parsed = parseInt(raceToInput, 10);
  return Number.isFinite(parsed) ? parsed : 0;
}

function formToSetupData(form: FormState): GameSetupData {
  const data: GameSetupData = {
    player1: form.player1,
    player2: form.player2,
    score1: form.score1,
    score2: form.score2,
    gameType: form.gameType,
    raceTo: parseRaceToValue(form.raceTo, form.raceToInput),
    breakRule: form.breakRule,
    breakOrder: form.breakOrder,
    currentBreakerIdx: form.currentBreakerIdx,
  };
  if (form.hasPlayer3) {
    data.player3 = form.player3;
    data.score3 = form.score3;
  }
  return data;
}

function choiceClass(selected: boolean): string {
  return `${styles.choiceBtn} ${selected ? styles.choiceBtnSelected : ''}`;
}

export function GameSetupModal({ game, open, onSave, onCancel }: GameSetupModalProps) {
  const [form, setForm] = useState<FormState>(() => setupToFormState(gameToSetupData(game)));
  const [errors, setErrors] = useState<string[]>([]);

  useEffect(() => {
    if (open) {
      setForm(setupToFormState(gameToSetupData(game)));
      setErrors([]);
    }
  }, [open, game]);

  if (!open) return null;

  const activeBreakerPlayer = form.breakOrder[form.currentBreakerIdx] ?? form.breakOrder[0];
  const playerLabels = [
    { num: 1, name: form.player1, score: form.score1 },
    { num: 2, name: form.player2, score: form.score2 },
    ...(form.hasPlayer3 ? [{ num: 3, name: form.player3, score: form.score3 }] : []),
  ];

  const updateForm = (patch: Partial<FormState>) => setForm((prev) => ({ ...prev, ...patch }));

  const togglePlayer3 = () => {
    if (form.hasPlayer3) {
      const order = [1, 2];
      let idx = form.currentBreakerIdx;
      const currentPlayer = form.breakOrder[idx];
      if (currentPlayer === 3) idx = 0;
      else idx = Math.min(idx, order.length - 1);
      updateForm({
        hasPlayer3: false,
        player3: '',
        score3: 0,
        breakOrder: order,
        currentBreakerIdx: idx,
      });
    } else {
      const order = [1, 2, 3];
      updateForm({
        hasPlayer3: true,
        player3: 'Spieler 3',
        score3: 0,
        breakOrder: order,
        currentBreakerIdx: Math.min(form.currentBreakerIdx, order.length - 1),
      });
    }
  };

  const selectBreaker = (playerNum: number) => {
    const idx = form.breakOrder.indexOf(playerNum);
    if (idx >= 0) updateForm({ currentBreakerIdx: idx });
  };

  const handleRaceQuickPick = (value: number) => {
    updateForm({ raceTo: value, raceToInput: String(value) });
  };

  const handleRaceInfinity = () => {
    updateForm({ raceTo: RACE_TO_INFINITY, raceToInput: '' });
  };

  const handleRaceInput = (e: Event) => {
    const value = (e.target as HTMLInputElement).value;
    const parsed = parseInt(value, 10);
    if (value === '') {
      updateForm({ raceToInput: '', raceTo: 0 });
      return;
    }
    if (!Number.isNaN(parsed)) {
      updateForm({ raceToInput: value, raceTo: parsed });
    }
  };

  const handleSave = () => {
    const data = formToSetupData(form);
    const result = validateGameSetupData(data);
    if (!result.isValid) {
      setErrors(result.errors);
      return;
    }
    setErrors([]);
    onSave(data);
  };

  const raceToNumber =
    form.raceTo === RACE_TO_INFINITY ? null : typeof form.raceTo === 'number' ? form.raceTo : parseInt(form.raceToInput, 10);

  return (
    <div
      className={`${modalStyles.modal} ${modalStyles.show}`}
      role="dialog"
      aria-modal="true"
      aria-labelledby="game-setup-modal-title"
    >
      <div className={`${modalStyles['modal-content']} ${styles.modalContent}`}>
        <div className={modalStyles['modal-header']}>
          <span className={modalStyles['modal-title']} id="game-setup-modal-title">
            Spiel einrichten
          </span>
          <button
            type="button"
            className={modalStyles['close-button']}
            onClick={onCancel}
            aria-label="Schließen"
          >
            ×
          </button>
        </div>

        <div className={modalStyles['modal-body']}>
          <Button
            variant="secondary"
            size="medium"
            className={styles.togglePlayerBtn}
            onClick={togglePlayer3}
            type="button"
          >
            {form.hasPlayer3 ? '3. Spieler entfernen' : '3. Spieler hinzufügen'}
          </Button>

          {playerLabels.map(({ num, name, score }) => (
            <div key={num} className={styles.playerRow}>
              <span className={styles.sectionTitle}>Spieler {num}</span>
              <div className={styles.fieldRow}>
                <input
                  type="text"
                  className={styles.textInput}
                  value={num === 1 ? form.player1 : num === 2 ? form.player2 : form.player3}
                  onInput={(e) => {
                    const v = (e.target as HTMLInputElement).value;
                    if (num === 1) updateForm({ player1: v });
                    else if (num === 2) updateForm({ player2: v });
                    else updateForm({ player3: v });
                  }}
                  aria-label={`Name Spieler ${num}`}
                  autoComplete="off"
                />
                <input
                  type="number"
                  min={0}
                  step={1}
                  inputMode="numeric"
                  className={styles.numberInput}
                  value={score}
                  onInput={(e) => {
                    const v = parseInt((e.target as HTMLInputElement).value, 10);
                    const safe = Number.isNaN(v) ? 0 : Math.max(0, v);
                    if (num === 1) updateForm({ score1: safe });
                    else if (num === 2) updateForm({ score2: safe });
                    else updateForm({ score3: safe });
                  }}
                  aria-label={`Punkte Spieler ${num}`}
                />
              </div>
            </div>
          ))}

          <section className={styles.section} aria-labelledby="setup-game-type">
            <span className={styles.sectionTitle} id="setup-game-type">Spieltyp</span>
            <div className={styles.choiceRow}>
              {GAME_TYPES.map(({ value, label }) => (
                <button
                  key={value}
                  type="button"
                  className={choiceClass(form.gameType === value)}
                  onClick={() => updateForm({ gameType: value })}
                >
                  {label}
                </button>
              ))}
            </div>
          </section>

          <section className={styles.section} aria-labelledby="setup-race-to">
            <span className={styles.sectionTitle} id="setup-race-to">Race To</span>
            <div className={styles.endlosRow}>
              <button
                type="button"
                className={choiceClass(form.raceTo === RACE_TO_INFINITY)}
                onClick={handleRaceInfinity}
              >
                Endlos
              </button>
            </div>
            <div className={styles.raceGrid}>
              {RACE_TO_QUICK_PICKS.map((value) => (
                <button
                  key={value}
                  type="button"
                  className={choiceClass(raceToNumber === value)}
                  onClick={() => handleRaceQuickPick(value)}
                >
                  {value}
                </button>
              ))}
            </div>
            <div className={styles.fieldRow} style={{ marginTop: 'var(--space-sm)' }}>
              <input
                type="number"
                min={1}
                step={1}
                inputMode="numeric"
                className={styles.textInput}
                value={form.raceTo === RACE_TO_INFINITY ? '' : form.raceToInput}
                onInput={handleRaceInput}
                placeholder="Eigener Wert"
                aria-label="Race To manuelle Eingabe"
              />
            </div>
          </section>

          <section className={styles.section} aria-labelledby="setup-break-rule">
            <span className={styles.sectionTitle} id="setup-break-rule">Break-Regel</span>
            <div className={styles.choiceRow}>
              {(
                [
                  { key: 'winnerbreak' as BreakRule, label: 'Winnerbreak' },
                  { key: 'wechselbreak' as BreakRule, label: 'Wechselbreak' },
                ] as const
              ).map((opt) => (
                <button
                  key={opt.key}
                  type="button"
                  className={choiceClass(form.breakRule === opt.key)}
                  onClick={() => updateForm({ breakRule: opt.key })}
                >
                  {opt.label}
                </button>
              ))}
            </div>
          </section>

          <section className={styles.section} aria-labelledby="setup-breaker">
            <span className={styles.sectionTitle} id="setup-breaker">Wer breakt?</span>
            <div className={styles.choiceRow}>
              {playerLabels.map(({ num, name }) => (
                <button
                  key={num}
                  type="button"
                  className={choiceClass(activeBreakerPlayer === num)}
                  onClick={() => selectBreaker(num)}
                >
                  {name.trim() || `Spieler ${num}`}
                </button>
              ))}
            </div>
          </section>

          {errors.length > 0 && (
            <div className={styles.errors} role="alert">
              <ul>
                {errors.map((err) => (
                  <li key={err}>{err}</li>
                ))}
              </ul>
            </div>
          )}
        </div>

        <div className={modalStyles['modal-footer']}>
          <div className={styles.footerActions}>
            <Button variant="secondary" size="large" onClick={onCancel} type="button">
              Abbrechen
            </Button>
            <Button variant="primary" size="large" onClick={handleSave} type="button">
              Übernehmen
            </Button>
          </div>
        </div>
      </div>
    </div>
  );
}