import { extend } from '../../../vue';
import { EVENT_NAME_ROW_CLICKED, EVENT_NAME_ROW_MIDDLE_CLICKED, EVENT_NAME_ROW_CONTEXTMENU, EVENT_NAME_ROW_DBLCLICKED } from '../../../constants/events';
import { CODE_ENTER, CODE_SPACE, CODE_UP, CODE_DOWN, CODE_HOME, CODE_END } from '../../../constants/key-codes';
import { PROP_TYPE_ARRAY_OBJECT_STRING } from '../../../constants/props';
import { from, arrayIncludes } from '../../../utils/array';
import { isElement, closest, isActiveElement, attemptFocus } from '../../../utils/dom';
import { safeVueInstance } from '../../../utils/safe-vue-instance';
import { stopEvent } from '../../../utils/events';
import { sortKeys } from '../../../utils/object';
import { makeProp, pluckProps } from '../../../utils/props';
import { props as props$1, BTbody } from '../tbody';
import { filterEvent } from './filter-event';
import { textSelectionActive } from './text-selection-active';
import { props as props$2, tbodyRowMixin } from './mixin-tbody-row';

// --- Helper methods ---

const getCellSlotName = value => `cell(${value || ''})`;

// --- Props ---

const props = sortKeys({
  ...props$1,
  ...props$2,
  tbodyClass: makeProp(PROP_TYPE_ARRAY_OBJECT_STRING)
});

// --- Mixin ---

// @vue/component
const tbodyMixin = extend({
  mixins: [tbodyRowMixin],
  props,
  beforeDestroy() {
    this.$_bodyFieldSlotNameCache = null;
  },
  methods: {
    // Returns all the item TR elements (excludes detail and spacer rows)
    // `this.$refs['item-rows']` is an array of item TR components/elements
    // Rows should all be `<b-tr>` components, but we map to TR elements
    // Also note that `this.$refs['item-rows']` may not always be in document order
    getTbodyTrs() {
      const {
        $refs
      } = this;
      const tbody = $refs.tbody ? $refs.tbody.$el || $refs.tbody : null;
      const trs = ($refs['item-rows'] || []).map(tr => tr.$el || tr);
      return tbody && tbody.children && tbody.children.length > 0 && trs && trs.length > 0 ? from(tbody.children).filter(tr => arrayIncludes(trs, tr)) : /* istanbul ignore next */[];
    },
    // Returns index of a particular TBODY item TR
    // We set `true` on closest to include self in result
    getTbodyTrIndex(el) {
      /* istanbul ignore next: should not normally happen */
      if (!isElement(el)) {
        return -1;
      }
      const tr = el.tagName === 'TR' ? el : closest('tr', el, true);
      return tr ? this.getTbodyTrs().indexOf(tr) : -1;
    },
    // Emits a row event, with the item object, row index and original event
    emitTbodyRowEvent(type, event) {
      if (type && event && event.target) {
        const rowIndex = this.getTbodyTrIndex(event.target);
        if (rowIndex > -1) {
          // The array of TRs correlate to the `computedItems` array
          const item = this.computedItems[rowIndex];
          if (this.hasListener(type)) {
            this.$emit(type, item, rowIndex, event);
          }
          // Call selectionHandler directly if selectable (defined in mixin-selectable.js)
          if (type === EVENT_NAME_ROW_CLICKED && this.hasSelectableRowClick) {
            this.selectionHandler(item, rowIndex, event);
          }
        }
      }
    },
    tbodyRowEventStopped(event) {
      return this.stopIfBusy && this.stopIfBusy(event);
    },
    // Delegated row event handlers
    onTbodyRowKeydown(event) {
      // Keyboard navigation and row click emulation
      const {
        target,
        keyCode
      } = event;
      if (this.tbodyRowEventStopped(event) || target.tagName !== 'TR' || !isActiveElement(target) || target.tabIndex !== 0) {
        // Early exit if not an item row TR
        return;
      }
      if (arrayIncludes([CODE_ENTER, CODE_SPACE], keyCode)) {
        // Emulated click for keyboard users, transfer to click handler
        stopEvent(event);
        this.onTBodyRowClicked(event);
      } else if (arrayIncludes([CODE_UP, CODE_DOWN, CODE_HOME, CODE_END], keyCode)) {
        // Keyboard navigation
        const rowIndex = this.getTbodyTrIndex(target);
        if (rowIndex > -1) {
          stopEvent(event);
          const trs = this.getTbodyTrs();
          const shift = event.shiftKey;
          if (keyCode === CODE_HOME || shift && keyCode === CODE_UP) {
            // Focus first row
            attemptFocus(trs[0]);
          } else if (keyCode === CODE_END || shift && keyCode === CODE_DOWN) {
            // Focus last row
            attemptFocus(trs[trs.length - 1]);
          } else if (keyCode === CODE_UP && rowIndex > 0) {
            // Focus previous row
            attemptFocus(trs[rowIndex - 1]);
          } else if (keyCode === CODE_DOWN && rowIndex < trs.length - 1) {
            // Focus next row
            attemptFocus(trs[rowIndex + 1]);
          }
        }
      }
    },
    onTBodyRowClicked(event) {
      const {
        $refs
      } = this;
      const tbody = $refs.tbody ? $refs.tbody.$el || $refs.tbody : null;
      // Don't emit event when the table is busy, the user clicked
      // on a non-disabled control or is selecting text
      if (this.tbodyRowEventStopped(event) || filterEvent(event) || textSelectionActive(tbody || this.$el)) {
        return;
      }
      this.emitTbodyRowEvent(EVENT_NAME_ROW_CLICKED, event);
    },
    onTbodyRowMiddleMouseRowClicked(event) {
      if (!this.tbodyRowEventStopped(event) && event.which === 2) {
        this.emitTbodyRowEvent(EVENT_NAME_ROW_MIDDLE_CLICKED, event);
      }
    },
    onTbodyRowContextmenu(event) {
      if (!this.tbodyRowEventStopped(event)) {
        this.emitTbodyRowEvent(EVENT_NAME_ROW_CONTEXTMENU, event);
      }
    },
    onTbodyRowDblClicked(event) {
      if (!this.tbodyRowEventStopped(event) && !filterEvent(event)) {
        this.emitTbodyRowEvent(EVENT_NAME_ROW_DBLCLICKED, event);
      }
    },
    // Render the tbody element and children
    // Note:
    //   Row hover handlers are handled by the tbody-row mixin
    //   As mouseenter/mouseleave events do not bubble
    renderTbody() {
      const {
        computedItems: items,
        renderBusy,
        renderTopRow,
        renderEmpty,
        renderBottomRow,
        hasSelectableRowClick
      } = safeVueInstance(this);
      const h = this.$createElement;
      const hasRowClickHandler = this.hasListener(EVENT_NAME_ROW_CLICKED) || hasSelectableRowClick;

      // Prepare the tbody rows
      const $rows = [];

      // Add the item data rows or the busy slot
      const $busy = renderBusy ? renderBusy() : null;
      if ($busy) {
        // If table is busy and a busy slot, then return only the busy "row" indicator
        $rows.push($busy);
      } else {
        // Table isn't busy, or we don't have a busy slot

        // Create a slot cache for improved performance when looking up cell slot names
        // Values will be keyed by the field's `key` and will store the slot's name
        // Slots could be dynamic (i.e. `v-if`), so we must compute on each render
        // Used by tbody-row mixin render helper
        const cache = {};
        let defaultSlotName = getCellSlotName();
        defaultSlotName = this.hasNormalizedSlot(defaultSlotName) ? defaultSlotName : null;
        this.computedFields.forEach(field => {
          const {
            key
          } = field;
          const slotName = getCellSlotName(key);
          const lowercaseSlotName = getCellSlotName(key.toLowerCase());
          cache[key] = this.hasNormalizedSlot(slotName) ? slotName : this.hasNormalizedSlot(lowercaseSlotName) ? /* istanbul ignore next */lowercaseSlotName : defaultSlotName;
        });
        // Created as a non-reactive property so to not trigger component updates
        // Must be a fresh object each render
        this.$_bodyFieldSlotNameCache = cache;

        // Add static top row slot (hidden in visibly stacked mode
        // as we can't control `data-label` attr)
        $rows.push(renderTopRow ? renderTopRow() : h());

        // Render the rows
        items.forEach((item, rowIndex) => {
          // Render the individual item row (rows if details slot)
          $rows.push(this.renderTbodyRow(item, rowIndex));
        });

        // Empty items / empty filtered row slot (only shows if `items.length < 1`)
        $rows.push(renderEmpty ? renderEmpty() : h());

        // Static bottom row slot (hidden in visibly stacked mode
        // as we can't control `data-label` attr)
        $rows.push(renderBottomRow ? renderBottomRow() : h());
      }

      // Note: these events will only emit if a listener is registered
      const handlers = {
        auxclick: this.onTbodyRowMiddleMouseRowClicked,
        // TODO:
        //   Perhaps we do want to automatically prevent the
        //   default context menu from showing if there is a
        //   `row-contextmenu` listener registered
        contextmenu: this.onTbodyRowContextmenu,
        // The following event(s) is not considered A11Y friendly
        dblclick: this.onTbodyRowDblClicked
        // Hover events (`mouseenter`/`mouseleave`) are handled by `tbody-row` mixin
      };
      // Add in click/keydown listeners if needed
      if (hasRowClickHandler) {
        handlers.click = this.onTBodyRowClicked;
        handlers.keydown = this.onTbodyRowKeydown;
      }

      // Assemble rows into the tbody
      const $tbody = h(BTbody, {
        class: this.tbodyClass || null,
        props: pluckProps(props$1, this.$props),
        // BTbody transfers all native event listeners to the root element
        // TODO: Only set the handlers if the table is not busy
        on: handlers,
        ref: 'tbody'
      }, $rows);

      // Return the assembled tbody
      return $tbody;
    }
  }
});

export { props, tbodyMixin };
