import UIButton from "@/components/ui/UIButton";
import { Colors } from "@/constants/theme";
import api from "@/utils/api";
import { DatePicker, Input, Modal, Radio, Toast } from "@ant-design/react-native";
import { Ionicons } from "@expo/vector-icons";
import { usePreventRemove, useRoute } from "@react-navigation/native";
import { NavigationAction } from "@react-navigation/routers";
import { Link, Stack, useNavigation } from "expo-router";
import React, { useCallback, useRef, useState } from "react";
import {
  KeyboardAvoidingView,
  Platform,
  Pressable,
  ScrollView,
  StyleSheet,
  Text,
  TextInput,
  View,
} from "react-native";
import { useSafeAreaInsets } from "react-native-safe-area-context";
import { UploadScreen } from "../credit/upload";

type CustomerForm = {
  name: string;
  mobile: string;
  gender: string;
  birthday?: Date;
  idcard: string;
  nation: string;
  registered: string;
  residential: string;
  photo: string;
  occupation: string;
  other: string;
};

type FieldKey = "name" | "mobile" | "idcard";
type FieldErrors = Partial<Record<FieldKey, string>>;
type BirthDateSource = "unset" | "manual" | "id-card";

type Option = {
  label: string;
  value: string;
};

const GENDER_OPTIONS: Option[] = [
  { label: "男", value: "1" },
  { label: "女", value: "2" },
  { label: "其它", value: "3" }
];

const MOBILE_PATTERN = /^1\d{10}$/;
const IDCARD_PATTERN = /^(?:\d{15}|\d{17}[\dX])$/;

const EMPTY_CUSTOMER_FORM: CustomerForm = {
  name: "",
  mobile: "",
  gender: "",
  birthday: undefined,
  idcard: "",
  nation: "",
  registered: "",
  residential: "",
  photo: "",
  occupation: "",
  other: "",
};

type CustomerExtPayload = {
  nation: string;
  registered: string | null;
  residential: string | null;
  photo: string | null;
  occupation: string | null;
  other: string | null;
};

type CustomerPayload = {
  name: string;
  mobile: string;
  gender: number;
  birthday: string | null;
  idcard: string;
  ext: CustomerExtPayload;
};

function sanitizePhone(value: string) {
  return value.replace(/\D/g, "").slice(0, 11);
}

function sanitizeIdCard(value: string) {
  return value.replace(/[^0-9xX]/g, "").toUpperCase().slice(0, 18);
}

function padZero(value: number) {
  return String(value).padStart(2, "0");
}

function formatDate(date?: Date) {
  if (!date) {
    return "";
  }

  return `${date.getFullYear()}-${padZero(date.getMonth() + 1)}-${padZero(date.getDate())}`;
}

function isValidDatePart(year: number, month: number, day: number) {
  if (year < 1900 || year > new Date().getFullYear()) {
    return false;
  }

  const date = new Date(year, month - 1, day);

  return (
    date.getFullYear() === year &&
    date.getMonth() === month - 1 &&
    date.getDate() === day &&
    date.getTime() <= Date.now()
  );
}

function inferBirthDateFromIdCard(idCard: string) {
  if (idCard.length < 14) {
    return undefined;
  }

  const birthText = idCard.slice(6, 14);
  if (!/^\d{8}$/.test(birthText)) {
    return undefined;
  }

  const year = Number(birthText.slice(0, 4));
  const month = Number(birthText.slice(4, 6));
  const day = Number(birthText.slice(6, 8));

  if (!isValidDatePart(year, month, day)) {
    return undefined;
  }

  return new Date(year, month - 1, day);
}

function nullableText(value: string) {
  const trimmed = value.trim();
  return trimmed || null;
}

function validateForm(form: CustomerForm): FieldErrors {
  const nextErrors: FieldErrors = {};
  const mobile = form.mobile.trim();
  const idcard = form.idcard.trim();

  if (!form.name.trim()) {
    nextErrors.name = "请输入客户姓名";
  }

  if (!mobile && !idcard) {
    nextErrors.mobile = "手机号和身份证号至少填写一项";
    nextErrors.idcard = "手机号和身份证号至少填写一项";
    return nextErrors;
  }

  if (mobile && !MOBILE_PATTERN.test(mobile)) {
    nextErrors.mobile = "请输入 11 位手机号";
  }

  if (idcard && !IDCARD_PATTERN.test(idcard)) {
    nextErrors.idcard = "请输入正确的身份证号";
  }

  return nextErrors;
}

function buildCustomerPayload(form: CustomerForm): CustomerPayload {
  return {
    name: form.name.trim(),
    mobile: form.mobile.trim(),
    gender: Number(form.gender) || 0,
    birthday: form.birthday ? formatDate(form.birthday) : null,
    idcard: form.idcard.trim(),
    ext: {
      nation: form.nation.trim(),
      registered: nullableText(form.registered),
      residential: nullableText(form.residential),
      photo: nullableText(form.photo),
      occupation: nullableText(form.occupation),
      other: nullableText(form.other),
    },
  };
}

function FieldLabel({
  label,
  required = false,
}: {
  label: string;
  required?: boolean;
}) {
  return (
    <View className="mb-2 flex-row items-center">
      <Text className="text-sm font-semibold text-on-surface">{label}</Text>
      {required ? <Text className="ml-1 text-sm font-semibold text-red-500">*</Text> : null}
    </View>
  );
}

function FieldMessage({
  error,
  helper,
}: {
  error?: string;
  helper?: string;
}) {
  if (error) {
    return <Text className="mt-2 text-xs leading-5 text-red-500">{error}</Text>;
  }

  if (helper) {
    return <Text className="mt-2 text-xs leading-5 text-on-surface-variant">{helper}</Text>;
  }

  return null;
}

function PickerField({
  label,
  required = false,
  value,
  placeholder,
  error,
  helper,
  disabled = false,
  onPress,
}: {
  label: string;
  required?: boolean;
  value?: string;
  placeholder: string;
  error?: string;
  helper?: string;
  disabled?: boolean;
  onPress: () => void;
}) {
  const hasValue = Boolean(value);

  return (
    <View className="mb-4">
      <FieldLabel label={label} required={required} />
      <Pressable
        disabled={disabled}
        onPress={onPress}
        className={`flex-row items-center justify-between rounded-2xl border px-4 py-4 ${error
          ? "border-red-300 bg-red-50"
          : "border-outline-variant bg-surface-container-low"
          }`}
        style={({ pressed }) => ({
          opacity: disabled ? 0.55 : pressed ? 0.9 : 1,
        })}
      >
        <Text
          className={`flex-1 text-base ${hasValue ? "text-on-surface" : "text-outline"}`}
          numberOfLines={1}
        >
          {hasValue ? value : placeholder}
        </Text>
        <Ionicons
          name="chevron-down"
          size={18}
          color={error ? "#ef4444" : Colors.color_text_paragraph}
        />
      </Pressable>
      <FieldMessage error={error} helper={helper} />
    </View>
  );
}

export default function AddCustomerScreen() {
  const insets = useSafeAreaInsets();
  const navigation = useNavigation();
  const [form, setForm] = useState<CustomerForm>(EMPTY_CUSTOMER_FORM);
  const [errors, setErrors] = useState<FieldErrors>({});
  const [birthDateSource, setBirthDateSource] = useState<BirthDateSource>("unset");
  const [saving, setSaving] = useState(false);
  const leaveConfirmVisibleRef = useRef(false);
  const savedLeaveRef = useRef(false);
  const route = useRoute();
  const scrollViewRef = useRef<ScrollView>(null!);

  const hasDraft = Boolean(
    form.name.trim() ||
    form.mobile.trim() ||
    form.gender ||
    form.birthday ||
    form.idcard.trim() ||
    form.nation.trim() ||
    form.registered.trim() ||
    form.residential.trim() ||
    form.photo.trim() ||
    form.occupation.trim() ||
    form.other.trim()
  );

  const openLeaveConfirm = useCallback(
    (action: NavigationAction) => {
      if (leaveConfirmVisibleRef.current) {
        return;
      }

      leaveConfirmVisibleRef.current = true;
      Modal.alert(
        "放弃当前编辑",
        "当前页面还有未保存的客户资料，确定要返回吗？",
        [
          {
            text: "继续编辑",
            style: "cancel",
            onPress: () => {
              leaveConfirmVisibleRef.current = false;
            },
          },
          {
            text: "确认返回",
            style: "destructive",
            onPress: () => {
              leaveConfirmVisibleRef.current = false;
              navigation.dispatch(action);
            },
          },
        ],
        () => {
          leaveConfirmVisibleRef.current = false;
          return true;
        }
      );
    },
    [navigation]
  );

  usePreventRemove(hasDraft, ({ data }) => {
    if (savedLeaveRef.current) {
      navigation.dispatch(data.action);
      return;
    }

    openLeaveConfirm(data.action);
  });

  const clearErrors = (keys: FieldKey[]) => {
    setErrors((prev) => {
      const next = { ...prev };
      keys.forEach((key) => {
        delete next[key];
      });
      return next;
    });
  };

  const handleNameChange = (value: string) => {
    setForm((prev) => ({ ...prev, name: value }));
    clearErrors(["name"]);
  };

  const handleMobileChange = (value: string) => {
    setForm((prev) => ({ ...prev, mobile: sanitizePhone(value) }));
    clearErrors(["mobile", "idcard"]);
  };

  const handleIdCardChange = (value: string) => {
    const nextIdCard = sanitizeIdCard(value);
    const inferredBirthDate = inferBirthDateFromIdCard(nextIdCard);
    const canAutofillBirthDate = birthDateSource !== "manual" || !form.birthday;
    setForm((prev) => ({
      ...prev,
      idcard: nextIdCard,
      birthday:
        inferredBirthDate && canAutofillBirthDate
          ? inferredBirthDate
          : !inferredBirthDate && birthDateSource === "id-card"
            ? undefined
            : prev.birthday,
    }));

    if (inferredBirthDate && canAutofillBirthDate) {
      setBirthDateSource("id-card");
    } else if (!inferredBirthDate && birthDateSource === "id-card") {
      setBirthDateSource("unset");
    }

    clearErrors(["mobile", "idcard"]);
  };
  const savedRef = useRef<boolean>(false);


  const onSelectCredis = (isCancel: boolean) => {
    setSelectCredit(false);
    // if (isCancel) {
    //   return;
    // }
    if (savedRef.current || !isCancel) {
      navigation.goBack();
      return;
    }
  }

  const handleSubmit = async () => {
    if (saving) {
      return;
    }

    const nextErrors = validateForm(form);
    setErrors(nextErrors);

    const firstError = Object.values(nextErrors)[0];
    if (firstError) {
      Toast.fail(firstError);
      scrollViewRef.current?.scrollTo({ y: 160, animated: true });
      return;
    }

    setSaving(true);
    const toastKey = Toast.loading("正在保存客户...");

    try {
      const customerId = await api.post("/customer/add", buildCustomerPayload(form));
      Toast.success("客户已保存");
      savedLeaveRef.current = true;
      // setForm(EMPTY_CUSTOMER_FORM);
      // setBirthDateSource("unset");
      // setErrors({});
      // @ts-ignore

      if (route.params?.onGoBack) {
        // @ts-ignore
        route.params.onGoBack({ customerId });
        navigation.goBack();
      } else {
        Modal.alert("客户添加完成", "是否立即上传征信信息", [{
          text: '否',
        }, {
          'text': '立即上传',
          onPress: () => {
            setSelectCredit(true);
          }
        }])
      }

    } catch (error) {
      console.error("保存客户失败:", error);
      Toast.fail(error instanceof Error ? error.message : "保存客户失败，请稍后重试");
    } finally {
      setSaving(false);
      Toast.remove(toastKey);
    }
  };


  const birthDateHelper =
    birthDateSource === "id-card"
      ? "已根据身份证自动识别，可继续手动调整"
      : "填写身份证后可自动识别，也可以手动选择";


  const [selectCredit, setSelectCredit] = useState(false);


  return (
    <View className="flex-1 bg-surface">
      <Stack.Screen options={{ title: "添加客户" }} />
      <KeyboardAvoidingView
        className="flex-1"
        behavior={Platform.OS === "ios" ? "padding" : undefined}
      >
        <ScrollView
          ref={scrollViewRef}
          className="flex-1"
          contentContainerClassName="px-5 pb-10"
          contentContainerStyle={{
            paddingTop: (insets.top ?? 0) + 60,
            paddingBottom: (insets.bottom ?? 0) + 28,
          }}
          keyboardShouldPersistTaps="handled"
          showsVerticalScrollIndicator={false}
        >
          <View className="mb-6">
            <Text className="text-3xl font-extrabold tracking-tight text-on-surface">
              新建客户
            </Text>
          </View>

          <View className="mb-5 rounded-3xl border border-blue-100 bg-primary-fixed px-4 py-4">
            <View className="flex-row items-start">
              <View className="mr-3 mt-0.5 h-10 w-10 items-center justify-center rounded-2xl bg-primary-container">
                <Ionicons name="information-circle-outline" size={20} color="#ffffff" />
              </View>
              <View className="flex-1">
                <Text className="text-base font-bold text-on-surface">提示：</Text>
                <Text className="mt-1 text-sm leading-6 text-on-surface-variant">
                  您可以先<Link href="/credit/select" replace asChild><Text className="text-primary font-bold">上传分析征信</Text></Link>，然后从已分析征信中<Link href="/credit/select" asChild><Text className="text-primary font-bold">选择</Text></Link>一条信息以填充客户资料。
                </Text>
              </View>
            </View>
          </View>


          <View className="mb-4">
            <FieldLabel label="姓名" required />
            <Input
              value={form.name}
              onChangeText={handleNameChange}
              placeholder="请输入客户姓名"
              allowClear
              status={errors.name ? "error" : undefined}
              style={[
                styles.inputContainer,
                errors.name ? styles.inputContainerError : undefined,
              ]}
              inputStyle={styles.inputText}
            />
            <FieldMessage error={errors.name} />
          </View>

          <View className="mb-4">
            <FieldLabel label="性别" />
            <Radio.Group
              value={form.gender}
              onChange={(event) => {
                const selected = event.target.value;
                if (typeof selected !== "string" && typeof selected !== "number") {
                  return;
                }

                setForm((prev) => ({
                  ...prev,
                  gender: String(selected),
                }));
              }}
              style={styles.radioGroup}
            >
              {GENDER_OPTIONS.map((option) => (
                <Radio key={option.value} value={option.value}>
                  {option.label}
                </Radio>
              ))}
            </Radio.Group>
          </View>

          <DatePicker
            precision="day"
            value={form.birthday}
            minDate={new Date(1950, 0, 1)}
            maxDate={new Date()}
            format={formatDate}
            onOk={(value) => {
              setForm((prev) => ({ ...prev, birthday: value }));
              setBirthDateSource("manual");
            }}
          >
            {({ disabled, toggle }) => (
              <PickerField
                label="出生日期"
                value={formatDate(form.birthday)}
                placeholder="请选择出生日期"
                helper={birthDateHelper}
                disabled={disabled}
                onPress={toggle}
              />
            )}
          </DatePicker>

          <View className="mb-4">
            <FieldLabel label="手机号" />
            <TextInput
              value={form.mobile}
              onChangeText={handleMobileChange}
              placeholder="请输入 11 位手机号"
              keyboardType="phone-pad"
              placeholderTextColor="#9ca3af"
              textContentType="telephoneNumber"
              underlineColorAndroid="transparent"
              maxLength={11}
              style={[
                styles.inputContainer,
                styles.inputText,
                errors.mobile ? styles.inputContainerError : undefined,
              ]}
            />
            <FieldMessage
              error={errors.mobile}
              helper={errors.mobile ? undefined : "手机号和身份证号至少填写一项"}
            />
          </View>

          <View className="mb-4">
            <FieldLabel label="身份证号" />
            <TextInput
              value={form.idcard}
              onChangeText={handleIdCardChange}
              placeholder="请输入身份证号"
              autoCapitalize="characters"
              autoCorrect={false}
              placeholderTextColor="#9ca3af"
              underlineColorAndroid="transparent"
              maxLength={18}
              style={[
                styles.inputContainer,
                styles.inputText,
                errors.idcard ? styles.inputContainerError : undefined,
              ]}
            />
            <FieldMessage
              error={errors.idcard}
              helper={errors.idcard ? undefined : "填写 18 位身份证后会自动识别出生日期"}
            />
          </View>

          <View className="mb-4">
            <FieldLabel label="民族" />
            <Input
              value={form.nation}
              onChangeText={(value) => setForm((prev) => ({ ...prev, nation: value }))}
              placeholder="请输入民族"
              allowClear
              maxLength={16}
              style={styles.inputContainer}
              inputStyle={styles.inputText}
            />
          </View>

          <View className="mb-4">
            <FieldLabel label="户籍所在地" />
            <Input
              value={form.registered}
              onChangeText={(value) => setForm((prev) => ({ ...prev, registered: value }))}
              placeholder="请输入户籍所在地"
              allowClear
              style={styles.inputContainer}
              inputStyle={styles.inputText}
            />
          </View>

          <View className="mb-4">
            <FieldLabel label="现居住地" />
            <Input
              value={form.residential}
              onChangeText={(value) => setForm((prev) => ({ ...prev, residential: value }))}
              placeholder="请输入现居住地"
              allowClear
              style={styles.inputContainer}
              inputStyle={styles.inputText}
            />
          </View>

          <View className="mb-4">
            <FieldLabel label="照片" />
            <Input
              value={form.photo}
              onChangeText={(value) => setForm((prev) => ({ ...prev, photo: value }))}
              placeholder="请输入照片地址"
              allowClear
              style={styles.inputContainer}
              inputStyle={styles.inputText}
            />
          </View>

          <View className="mb-4">
            <FieldLabel label="职业" />
            <Input
              value={form.occupation}
              onChangeText={(value) => setForm((prev) => ({ ...prev, occupation: value }))}
              placeholder="请输入职业"
              allowClear
              style={styles.inputContainer}
              inputStyle={styles.inputText}
            />
          </View>

          <View>
            <FieldLabel label="其它" />
            <Input.TextArea
              value={form.other}
              onChangeText={(value) => setForm((prev) => ({ ...prev, other: value }))}
              placeholder="补充备注、渠道来源、客户标签等"
              autoSize={{ minRows: 4, maxRows: 6 }}
              maxLength={200}
              showCount
              allowClear
              style={styles.textAreaContainer}
              inputStyle={styles.textAreaText}
            />
          </View>

          <UIButton type="primary" icon="save" onPress={handleSubmit} disabled={saving} loading={saving}>
            保存客户
          </UIButton>
        </ScrollView>
      </KeyboardAvoidingView>
      <UploadScreen visible={selectCredit} onClose={onSelectCredis} />
    </View>
  );
}

const styles = StyleSheet.create({
  inputContainer: {
    minHeight: 54,
    borderRadius: 16,
    borderWidth: 1,
    borderColor: Colors.border_color_base,
    backgroundColor: Colors.fill_body,
    paddingHorizontal: 14,
  },
  inputContainerError: {
    borderColor: "#fca5a5",
    backgroundColor: "#fef2f2",
  },
  inputText: {
    color: Colors.color_text_base,
    fontSize: 16,
    paddingVertical: Platform.OS === "web" ? 12 : 10,
  },
  radioGroup: {
    flexDirection: "row",
    gap: 24,
    minHeight: 44,
    alignItems: "center",
  },
  textAreaContainer: {
    borderRadius: 16,
    borderWidth: 1,
    borderColor: Colors.border_color_base,
    backgroundColor: Colors.fill_body,
    paddingHorizontal: 14,
    paddingTop: 12,
    paddingBottom: 12,
  },
  textAreaText: {
    color: Colors.color_text_base,
    fontSize: 16,
    lineHeight: 22,
    minHeight: 96,
    textAlignVertical: "top",
  },
});