import { ref, watchEffect, onBeforeUnmount } from 'vue';

// 模拟 FocusHandledResult 枚举
enum FocusHandledResult {
  System,
  Self
}

// 模拟 Platform.Hotkeys.HotKeyHelper
class HotKeyHelper {
  static GetKeyName(key: KeyboardEvent['key']): string {
    // 简单实现，实际需要根据具体逻辑修改
    return key;
  }
}

// 模拟 BufferTimer
class BufferTimer {
  private buffer: KeyboardEvent['key'][] = [];
  private static instance: BufferTimer;

  private constructor() {}

  static get Instance() {
    if (!this.instance) {
      this.instance = new BufferTimer();
    }
    return this.instance;
  }

  Add(key: KeyboardEvent['key']) {
    this.buffer.push(key);
  }

  GetBuffer() {
    return this.buffer;
  }
}

// ComboBoxHelper 类
export class ComboBoxHelper {
  static readonly PartEditableTextBox = 'PART_EditableTextBox';

  private interval: ReturnType<typeof setTimeout> | null = null;
  private editTextBox: HTMLInputElement | null = null;
  private isKeyEvent = ref(false);
  private coll: any[] = [];
  private oldSelStart = 0;
  private oldSelLength = 0;
  private oldText = '';

  // 自动完成功能相关
  static GetIsAutoComplete(obj: any): boolean {
    return obj.IsAutoComplete;
  }

  static SetIsAutoComplete(obj: any, value: boolean) {
    obj.IsAutoComplete = value;
    if (value) {
      obj.style = 'AutoCompleteComboBox';
    } else {
      obj.style = 'default';
    }
  }

  RefreshSource(cbx: HTMLSelectElement, items: any[]) {
    this.coll = items;

    if (this.interval) {
      clearTimeout(this.interval);
    }

    this.interval = setTimeout(() => {
      this.isKeyEvent.value = false;
      cbx.open = true;
      // 刷新数据源视图，这里简单模拟
      this.filterItems(cbx);
    }, 600);

    if (this.editTextBox) {
      this.editTextBox.addEventListener('input', this.handleTextChanged);
    }
  }

  RegisteAutoComplete(cbx: HTMLSelectElement, items: any[]) {
    this.editTextBox = cbx.querySelector<HTMLInputElement>(`[name="${ComboBoxHelper.PartEditableTextBox}"]`);
    if (!this.editTextBox) {
      return false;
    }

    if (this.interval) {
      clearTimeout(this.interval);
    }

    this.interval = setTimeout(() => {
      this.isKeyEvent.value = false;
      cbx.open = true;
      // 刷新数据源视图，这里简单模拟
      this.filterItems(cbx);
    }, 600);

    this.editTextBox.addEventListener('input', this.handleTextChanged);
    this.editTextBox.addEventListener('keydown', this.handlePreviewKeyDown);

    cbx.addEventListener('mousedown', this.handleGotMouseCapture);
    cbx.addEventListener('open', this.handleDropDownOpened);
    cbx.addEventListener('focus', this.handleGotFocus);
    cbx.addEventListener('change', this.handleSelectionChanged);
    cbx.addEventListener('blur', this.handleLostFocus);

    this.coll = items;
    this.filterItems(cbx);

    return true;
  }

  private handleTextChanged = () => {
    if (!this.editTextBox) {
      return;
    }

    if (this.editTextBox.value === '') {
      // 刷新数据源视图，这里简单模拟
      this.filterItems(this.editTextBox.closest('select') as HTMLSelectElement);
    } else if (this.isKeyEvent.value) {
      const cbx = this.editTextBox.closest('select') as HTMLSelectElement;
      cbx.selectedIndex = -1;
      if (this.interval) {
        clearTimeout(this.interval);
      }
      this.interval = setTimeout(() => {
        this.isKeyEvent.value = false;
        cbx.open = true;
        // 刷新数据源视图，这里简单模拟
        this.filterItems(cbx);
      }, 600);
    }
  };

  private handlePreviewKeyDown = (e: KeyboardEvent) => {
    const pressKey = HotKeyHelper.GetKeyName(e.key);
    if (e.key !== 'ArrowUp' && e.key !== 'ArrowDown' && pressKey !== 'UNFOLD') {
      this.isKeyEvent.value = true;
    }
  };

  private handleGotMouseCapture = () => {
    if (this.editTextBox) {
      this.oldSelStart = this.editTextBox.selectionStart || 0;
      this.oldSelLength = this.editTextBox.selectionLength || 0;
      this.oldText = this.editTextBox.value;
    }
  };

  private handleDropDownOpened = () => {
    if (this.editTextBox) {
      this.editTextBox.value = this.oldText;
      this.editTextBox.selectionStart = this.oldSelStart;
      this.editTextBox.selectionLength = this.oldSelLength;
    }
  };

  private handleGotFocus = () => {
    if (this.editTextBox) {
      this.editTextBox.focus();
    }
  };

  private handleSelectionChanged = () => {
    if (this.interval) {
      clearTimeout(this.interval);
    }
  };

  private handleLostFocus = () => {
    this.isKeyEvent.value = false;
    const cbx = this.editTextBox?.closest('select') as HTMLSelectElement;
    cbx.open = false;

    if (cbx.selectedIndex === -1) {
      if (this.editTextBox) {
        this.editTextBox.value = '';
      }
    } else {
      if (this.editTextBox) {
        const selectedItem = cbx.options[cbx.selectedIndex];
        this.editTextBox.value = selectedItem.textContent || '';
      }
    }

    if (this.interval) {
      clearTimeout(this.interval);
    }

    try {
      if (this.editTextBox) {
        this.editTextBox.selectionStart = 0;
      }
    } catch (error) {
      // 忽略异常
    }
  };

  private filterItems(cbx: HTMLSelectElement) {
    if (!this.editTextBox) {
      return;
    }

    const filterText = this.editTextBox.value.toUpperCase();
    for (let i = 0; i < cbx.options.length; i++) {
      const option = cbx.options[i];
      if (filterText === '' || option.textContent?.toUpperCase().includes(filterText)) {
        option.style.display = 'block';
      } else {
        option.style.display = 'none';
      }
    }
  }

  // 焦点处理方法
  static ComboBoxFocusHandled = (sender: HTMLSelectElement, e: KeyboardEvent): FocusHandledResult => {
    if (!sender) {
      return FocusHandledResult.System;
    }

    if (sender.open && (e.key === 'ArrowUp' || e.key === 'ArrowDown' || e.key === 'Enter')) {
      if (e.key === 'ArrowUp' || e.key === 'ArrowDown') {
        return FocusHandledResult.Self;
      } else {
        // 执行焦点移动操作，这里简单模拟
        console.log('Move focus');
        return FocusHandledResult.Self;
      }
    }

    const pressKey = HotKeyHelper.GetKeyName(e.key);
    if (e.key === '+' || e.key === 'F2') {
      pressKey = 'UNFOLD';
    }

    if (pressKey === 'UNFOLD') {
      sender.open = !sender.open;
      return FocusHandledResult.Self;
    }

    if (sender.options.length > 0) {
      BufferTimer.Instance.Add(e.key);
      const keys = BufferTimer.Instance.GetBuffer().map((key) => {
        const keyCode = key.charCodeAt(0);
        let result = ' ';
        if (keyCode > 47 && keyCode < 58) {
          result = (keyCode - 48).toString();
        } else if (keyCode > 95 && keyCode < 106) {
          result = (keyCode - 96).toString();
        }
        return result;
      });

      if (keys.length === (sender.options.length - 1).toString().length) {
        const indexBuffer = keys.join('');
        const index = parseInt(indexBuffer, 10);
        if (!isNaN(index) && index >= 0 && index < sender.options.length) {
          sender.selectedIndex = index;
        }
      }
    }

    return FocusHandledResult.System;
  };

  static ComboBoxNormalFocusHandled = (sender: HTMLSelectElement, e: KeyboardEvent): FocusHandledResult => {
    if (!sender) {
      return FocusHandledResult.System;
    }

    if (sender.open && (e.key === 'ArrowUp' || e.key === 'ArrowDown' || e.key === 'Enter')) {
      return FocusHandledResult.Self;
    }

    const pressKey = HotKeyHelper.GetKeyName(e.key);
    if (pressKey === 'UNFOLD') {
      sender.open = !sender.open;
      return FocusHandledResult.Self;
    }

    return FocusHandledResult.System;
  };

  // 鼠标事件处理
  static ComboBoxHandled = (sender: HTMLSelectElement, e: MouseEvent): FocusHandledResult => {
    if (!sender) {
      return FocusHandledResult.System;
    }

    const originalSourceElement = e.target as HTMLElement;
    const clickedElement = originalSourceElement.closest('option');

    if (sender.open && e.button === 0 && clickedElement) {
      // 执行焦点移动操作，这里简单模拟
      console.log('Move focus');
      return FocusHandledResult.Self;
    }

    return FocusHandledResult.System;
  };

  // 延迟事件处理
  static DoWork(action: () => void, millisecond = 100) {
    setTimeout(action, millisecond);
  }

  static DoMouseWork(action: () => void, millisecond = 250) {
    setTimeout(action, millisecond);
  }

  static MoveFocusHandled() {
    // 焦点移动，这里简单模拟
    console.log('Move focus');
  }

  static MouseMoveFocusHandled() {
    // 焦点移动，这里简单模拟
    console.log('Move focus');
  }
}