import { useState } from 'react';
import { Ionicons } from '@expo/vector-icons';
import { useRouter } from 'expo-router';
import { Pressable, StyleSheet, Text, TextInput, View } from 'react-native';
import { colors, spacing } from '../../../src/theme';
import { useAgreementGate, useOnboarding, usePasswordReset, useSmsCode } from '../../../src/hooks';
import { isValidPhone, isValidSmsCode, SMS_CODE_MAX_LENGTH } from '../../../src/utils';
import { useAuth } from '../../../src/context/AuthContext';
import { useRole } from '../../../src/context/RoleContext';
import { PasswordField } from '../../../src/components/PasswordField';
import { ScreenShell } from '../ui/ScreenShell';
import { CountdownButton } from '../ui/CountdownButton';
import { PrimaryButton } from '../ui/PrimaryButton';
import { AgreementModal } from '../ui/AgreementModal';

/** 重置阶段：验证手机号 → 设置新密码 */
type Stage = 'verify' | 'password';

/**
 * P2R 设置 / 重置登录密码（同页两阶段）。
 *
 * 一个页面同时承担两件事：
 * 1. 忘记密码 —— 老用户忘记原密码，验证手机号后重设；
 * 2. 首次设置密码 —— 「登录即注册」的用户天生没有密码，走同一入口首次获得密码。
 * 因此文案对两者都成立，不区分来源，避免出现「有密码登录入口但没人拿得到密码」的死结。
 */
export function P2PasswordReset() {
  const { data, setData, navigate, back } = useOnboarding();
  const { gate, modalProps } = useAgreementGate();
  const { reset, loading, error, checkPassword } = usePasswordReset();
  const { send: sendCode, error: smsError } = useSmsCode();
  /** 重置成功即写入登录态，用户不必再用新密码登录一次 */
  const { login: writeAuth } = useAuth();
  const { role } = useRole();
  const router = useRouter();

  const [stage, setStage] = useState<Stage>('verify');
  const [code, setCode] = useState('');
  const [password, setPassword] = useState('');
  const [confirm, setConfirm] = useState('');

  const phone = data.phone;
  const phoneValid = isValidPhone(phone);
  const codeValid = isValidSmsCode(code);

  /** 密码规则提示（规则在 API 层计算，这里只渲染文案） */
  const hint = password.length > 0 ? checkPassword(password, confirm) : null;
  const canSubmit = codeValid && password.length > 0 && confirm.length > 0 && hint === null && !loading;

  /**
   * 发送验证码（只发送，不切阶段）。
   * 验证码是否正确由最终提交时的后端校验统一判定，本步不做本地校验，
   * 避免「前端说对了、后端说错了」的不一致。
   */
  const sendCodeNow = async () => {
    if (!phoneValid) return;
    try {
      await sendCode(phone, 'reset-password');
    } catch {
      // 失败原因由 useSmsCode 记录，页面下方展示
    }
  };

  const handleSubmit = async () => {
    if (!canSubmit) return;
    let result;
    try {
      result = await reset({ phone, code, password });
      writeAuth(result.token);
    } catch {
      // 失败原因由 usePasswordReset 记录，页面下方展示
      return;
    }

    // 已有身份的老用户直接进对应主界面，新用户才去选身份
    if (role) {
      router.replace(role === 'enterprise' ? '/(enterprise)/job-management' : '/(tabs)/jobs');
      return;
    }
    navigate('P3');
  };

  return (
    <ScreenShell showBack onBack={stage === 'password' ? () => setStage('verify') : back}>
      {stage === 'verify' ? (
        /* ---------- 阶段1：验证手机号 ---------- */
        <View>
          <Text style={styles.h1}>验证手机号</Text>
          <Text style={styles.subtitle}>验证通过后即可设置新的登录密码</Text>

          <View style={styles.fieldRow}>
            <Text style={styles.prefix}>+86</Text>
            <Ionicons name="caret-down" size={14} color={colors.textSecondary} />
            <View style={styles.divider} />
            <TextInput
              style={styles.input}
              value={phone}
              onChangeText={(t) => setData({ phone: t.replace(/[^\d]/g, '').slice(0, 11) })}
              placeholder="请输入手机号"
              placeholderTextColor={colors.textHint}
              keyboardType="phone-pad"
              maxLength={11}
            />
            {phone.length > 0 ? (
              <Pressable onPress={() => setData({ phone: '' })} hitSlop={8}>
                <Ionicons name="close-circle" size={18} color={colors.textDisabled} />
              </Pressable>
            ) : null}
          </View>
          <View style={styles.underline} />

          <View style={styles.fieldRow}>
            <TextInput
              style={styles.input}
              value={code}
              onChangeText={(t) => setCode(t.replace(/[^\d]/g, '').slice(0, SMS_CODE_MAX_LENGTH))}
              placeholder="请输入验证码"
              placeholderTextColor={colors.textHint}
              keyboardType="number-pad"
              maxLength={SMS_CODE_MAX_LENGTH}
            />
            <CountdownButton disabled={!phoneValid} onSend={() => void sendCodeNow()} />
          </View>
          <View style={styles.underline} />

          <View style={styles.btnArea}>
            <PrimaryButton
              label="下一步"
              active={phoneValid && codeValid}
              onPress={() => gate(() => setStage('password'))}
            />
          </View>

          {smsError ? <Text style={styles.formError}>{smsError.message}</Text> : null}
        </View>
      ) : (
        /* ---------- 阶段2：设置新密码 ---------- */
        <View>
          <Text style={styles.h1}>设置登录密码</Text>
          <Text style={styles.subtitle}>设置后可用手机号 + 密码登录</Text>

          <View style={styles.passwordArea}>
            <PasswordField value={password} onChangeText={setPassword} placeholder="请输入新密码" />
          </View>

          <View style={styles.passwordArea}>
            <PasswordField value={confirm} onChangeText={setConfirm} placeholder="请再次输入新密码" />
          </View>

          {hint ? (
            <Text style={styles.hintDanger}>{hint}</Text>
          ) : (
            <Text style={styles.hint}>8–20 位，需同时包含字母和数字</Text>
          )}

          <View style={styles.btnArea}>
            <PrimaryButton label="完成" active={canSubmit} loading={loading} onPress={() => gate(handleSubmit)} />
          </View>

          {error ? <Text style={styles.formError}>{error.message}</Text> : null}
        </View>
      )}

      <AgreementModal {...modalProps} />
    </ScreenShell>
  );
}

const styles = StyleSheet.create({
  h1: { fontSize: 26, fontWeight: '800', color: colors.textPrimary, marginTop: spacing.block },
  subtitle: { fontSize: 14, color: colors.textSecondary, marginTop: spacing.sm },
  fieldRow: { flexDirection: 'row', alignItems: 'center', height: 56, marginTop: 26, gap: 6 },
  prefix: { fontSize: 17, fontWeight: '700', color: colors.textPrimary },
  divider: { width: 1, height: 20, backgroundColor: colors.border, marginHorizontal: 10 },
  input: { flex: 1, fontSize: 17, color: colors.textPrimary, padding: 0 },
  underline: { height: 1, backgroundColor: colors.borderLight },
  passwordArea: { marginTop: spacing.section },
  hint: { marginTop: spacing.block, fontSize: 12, color: colors.textHint },
  hintDanger: { marginTop: spacing.block, fontSize: 12, color: colors.danger },
  btnArea: { marginTop: 26 },
  formError: { marginTop: spacing.sm, textAlign: 'center', fontSize: 12, color: colors.danger },
});