import { init, type InitResult,createElement, type Payment } from '@airwallex/components-sdk';
import { env } from "@/env";

// ============================================================
// Types
// ============================================================
export type AirwallexCartNumberElementType = Payment.CardNumberElementType;
export type AirwallexCvcElementType = Payment.CvcElementType;
export type AirwallexExpiryDateElementType = Payment.ExpiryDateElementType;

export interface AirwallexCardElements{
  cardNumber?: AirwallexCartNumberElementType;
  cvc?: AirwallexCvcElementType;
  expiry?: AirwallexExpiryDateElementType;
}

type ElementType =
  | AirwallexCartNumberElementType
  | AirwallexCvcElementType
  | AirwallexExpiryDateElementType;

// ============================================================
// Snapshot
// ============================================================
export interface AirwallexCardSnapshot {
    cardNumberReady: boolean;
    cvcReady: boolean;
    expiryReady: boolean;

    cardNumberValid: boolean;
    cvcValid: boolean;
    expiryValid: boolean;

    cardNumberErrorMsg: string;
    cvcErrorMsg: string;
    expiryErrorMsg: string;
}

// ============================================================
// Initial Snapshot
// ============================================================

const initialSnapshot: AirwallexCardSnapshot = {
    cardNumberReady: false,
    cvcReady: false,
    expiryReady: false,

    cardNumberValid: false,
    cvcValid: false,
    expiryValid: false,

    cardNumberErrorMsg: '',
    cvcErrorMsg: '',
    expiryErrorMsg: '',
};
// ============================================================
// Airwallex SDK init
// ============================================================
let initPromise: Promise<InitResult> | null = null;


export function airwallexInit() {


  if (!initPromise) {

    initPromise = init({
      env:
        env.NEXT_PUBLIC_APP_ENV !== 'production'
          ? 'demo'
          : 'prod',

      enabledElements: ['payments'],
    }).catch((err) => {
      initPromise = null;
      throw err;
    });

  }


  return initPromise;
}

// ============================================================
// Manager
// ============================================================
// 创建的cardNumber,cvc,expiry输入框挂载到页面上的某个元素上才能渲染出来
// 修改购物车数据后，需要重新获取支付方式列表，要想实现销毁-->重建卡支付输入框，必须要在销毁后把挂载的那个元素也删除，否则新创建的输入框上的绑定的事件会重发触发
// 所以进行此次优化
class AirwallexManager {
    // --------------------------------------------------------
    // Airwallex Elements
    // --------------------------------------------------------
  private elements: AirwallexCardElements = {};

  private createPromise: Promise<AirwallexCardElements> | null = null;

  // 引入使用者计数（现在是全局单例模式，这里的全局指的是以页面的生命周期为准，对于卡支付输入框，全局只有一个地方可以初始化，每次初始化后，全局只有一个实例）
  // 所以这里引入的refCount是一个过度防御
  // 当把airwallex的卡支付初始化与卡支付输入框的状态订阅拆分后，这个refCount已不那么需要（可以删除），但还是保留
  private refCount = 0;

  // --------------------------------------------------------
  // React external store
  // --------------------------------------------------------
  private snapshot: AirwallexCardSnapshot = {
      ...initialSnapshot,
  };

  private listeners = new Set<() => void>(); // 集合类型，用来保存监听器

  // 参数listener是react内部的监听函数
  // 当把subscribe传给useSyncExternalStore后，react在内部调用subscribe时把自己的监听函数传给subscribe
  subscribe = (listener: () => void) => {
      // 把react的监听函数保存到集合
      this.listeners.add(listener);
      
      // 取消订阅时（比如组件卸载时），删除保存的监听函数
      return () => {
          this.listeners.delete(listener);
      };
  };

  // react传给subscribe的监听函数里会调用getSnapshot重新获取数据快照
  getSnapshot = () => {
      return this.snapshot;
  };
  private emit() {

      this.listeners.forEach((listener) => {
          listener();
      });
  }
  private updateSnapshot( patch: Partial<AirwallexCardSnapshot> ) {
      this.snapshot = {
          ...this.snapshot,
          ...patch,
      };
      // 修改数据后，触发react的监听器，监听器里重现获取数据快照，数据变了，react重新渲染组件
      this.emit();
  }

  private resetSnapshot() {
      this.snapshot = {
          ...initialSnapshot,
      };

      this.emit();
  }
  // 
  setRefCount() {
    this.refCount++;
    console.log(
        '[Airwallex] acquire:',
        this.refCount
    );
  }
  release() {
    if (this.refCount === 0) {
        return;
    }

    this.refCount--;

    console.log(
        '[Airwallex] release:',
        this.refCount
    );

    if (this.refCount === 0) {
      console.log('_____________________________AirwallexCard destory ___________________________________')
        this.destroy();
    }

  }


  async createElements() {

    if (this.elements.cardNumber) {

      return this.elements;
    }

    if (this.createPromise) {

      return this.createPromise;
    }
    
    this.createPromise = Promise.all([
      createElement("cardNumber"),
      createElement("cvc"),
      createElement("expiry")
    ]).then(([cardNumber,cvc,expiry]) => {

      this.elements = {
        cardNumber,
        cvc,
        expiry
      };

      return this.elements;

    }).catch((error) => {

        // 创建失败，允许下一次重新创建
        this.createPromise = null;

        throw error;
    });

    return this.createPromise;

  }

  mount(containerIds: {
    cardNumber: string;
    cvc: string;
    expiry: string;
  }) {
    this.elements.cardNumber?.mount(containerIds.cardNumber);
    this.elements.cvc?.mount(containerIds.cvc);
    this.elements.expiry?.mount(containerIds.expiry);
  }

  on<EventCode extends Payment.SplitElementEventCode>(
    el: ElementType, 
    event: EventCode, 
    handler: Payment.SplitElementEventHandler<EventCode>
  ) {

    el.on(event, handler);
  }

  elementsBindHandler() {
    const { cardNumber, cvc, expiry } = this.elements;
    if(!cardNumber || !cvc || !expiry) {
      throw new Error('Airwallex elements have not been created!');
    }
    cardNumber.on("focus", (e) => {
      this.handleFocus(e)
    });
    cardNumber.on("blur", (e) => {
      this.handleBlur(e);
    });
    cardNumber.on("change", (e) => {
      this.handleChange(e);
    });
    cardNumber.on("ready", (e) => {
      this.handleReady(e);
    });

    cvc.on("focus", (e) => {
      this.handleFocus(e)
    });
    cvc.on("blur", (e) => {
      this.handleBlur(e);
    });
    cvc.on("change", (e) => {
      this.handleChange(e);
    });
    cvc.on("ready", (e) => {
      this.handleReady(e);
    });

    expiry.on("focus", (e) => {
      this.handleFocus(e)
    });
    expiry.on("blur", (e) => {
      this.handleBlur(e);
    });
    expiry.on("change", (e) => {
      this.handleChange(e);
    });
    expiry.on("ready", (e) => {
      this.handleReady(e);
    });

  }

  // ========================================================
  // Airwallex event handlers
  // ========================================================

    handleReady(event: any) {
      console.log('-----------------airwallex card ready-----------------');
        const { type } = event.detail;

        if (type === 'cardNumber') {
            this.updateSnapshot({
                cardNumberReady: true,
            });
            return;
        }
        if (type === 'cvc') {
            this.updateSnapshot({
                cvcReady: true,
            });
            return;
        }
        if (type === 'expiry') {
            this.updateSnapshot({
                expiryReady: true,
            });
            return;
        }
    }

    handleChange(event: any) {

        const {
            type,
            complete,
            error,
        } = event.detail;

        const message = error?.message ?? '';

        if (type === 'cardNumber') {

            this.updateSnapshot({
                cardNumberValid: complete,
                cardNumberErrorMsg: message,
            });

            return;
        }


        if (type === 'cvc') {

            this.updateSnapshot({
                cvcValid: complete,
                cvcErrorMsg: message,
            });

            return;
        }


        if (type === 'expiry') {

            this.updateSnapshot({
                expiryValid: complete,
                expiryErrorMsg: message,
            });

            return;
        }
    }


    handleFocus(event: any) {

        const { type } = event.detail;

        if (type === 'cardNumber') {

            this.updateSnapshot({
                cardNumberErrorMsg: '',
            });

            return;
        }


        if (type === 'cvc') {

            this.updateSnapshot({
                cvcErrorMsg: '',
            });

            return;
        }


        if (type === 'expiry') {

            this.updateSnapshot({
                expiryErrorMsg: '',
            });

            return;
        }
    }


    handleBlur(event: any) {

        const {
            type,
            error,
        } = event.detail;

        const message = error?.message ?? JSON.stringify(error);


        if (type === 'cardNumber') {

            this.updateSnapshot({
                cardNumberErrorMsg: message,
            });

            return;
        }


        if (type === 'cvc') {

            this.updateSnapshot({
                cvcErrorMsg: message,
            });

            return;
        }


        if (type === 'expiry') {

            this.updateSnapshot({
                expiryErrorMsg: message,
            });

            return;
        }
    }


    // ========================================================
    // Validation
    // ========================================================

    validateCard(): {valid: boolean; msg: string} {

        const state = this.snapshot;

        if (!state.cardNumberReady) {
            return {
              valid: false,
              msg: 'Card number input has not ready. Please wait a minute.'
            };
        }

        if (!state.expiryReady) {
            return {
              valid: false,
              msg: 'Card expiry date input has not ready. Please wait a minute.'
            };
        }

        if (!state.cvcReady) {
            return {
              valid: false,
              msg: 'Card cvc input has not ready. Please wait a minute.'
            };
        }


        if (!state.cardNumberValid) {
            return {
              valid: false,
              msg: state.cardNumberErrorMsg || 'Please input your card number.'
            };
        }

        if (!state.expiryValid) {
            return {
                valid: false,
                msg: state.expiryErrorMsg || 'Please input expiry date.'
            };
        }

        if (!state.cvcValid) {
            return {
                valid: false,
                msg: state.cvcErrorMsg || 'Please input cvc.'
            };
        }

        return {
          valid: true,
          msg: ''
        };
    }


    

  destroy() {
    const { cardNumber, cvc, expiry } = this.elements;

    [cardNumber, cvc, expiry].forEach((el) => {
      if (!el) return;
      el.unmount();
      el.destroy();
    });

    this.elements = {};
    this.createPromise=null;
    this.resetSnapshot();

  }

  getElements() {
    return this.elements;
  }

  getCardNumberElement() {
      return this.elements.cardNumber;
  }
}

export const airwallexManager = new AirwallexManager();