import Component from '@/ecs/component.js';

export default class Inventory extends Component {
  insertMany(entities) {
    for (const [id, {slotChange}] of entities) {
      if (slotChange) {
        const {slots} = this.get(id);
        for (const slotIndex in slotChange) {
          if (false === slotChange[slotIndex]) {
            delete slots[slotIndex];
          }
          else {
            slots[slotIndex] = {
              ...slots[slotIndex],
              ...slotChange[slotIndex],
            };
          }
        }
      }
    }
    return super.insertMany(entities);
  }
  instanceFromSchema() {
    const Instance = super.instanceFromSchema();
    const Component = this;
    return class InventoryInstance extends Instance {
      $$items = {};
      item(slot) {
        return this.$$items[slot];
      }
      swapSlots(l, r) {
        const {slots} = this;
        const tmp = slots[l];
        const change = {};
        if (slots[r]) {
          change[l] = slots[l] = slots[r];
        }
        else {
          change[l] = false;
          delete slots[l];
        }
        if (tmp) {
          change[r] = slots[r] = tmp;
        }
        else {
          change[r] = false;
          delete slots[r];
        }
        Component.markChange(this.entity, 'slotChange', change);
      }
    }
  }
  async load(instance) {
    const Component = this;
    const {readAsset} = this.ecs;
    const {slots} = instance;
    class ItemProxy {
      constructor(slot, json) {
        this.json = json;
        this.slot = slot;
      }
      project(position, direction) {
        const {TileLayers: {layers: [layer]}} = Component.ecs.get(1);
        const {projection} = this.json;
        let startX = position.x;
        let startY = position.y;
        switch (direction) {
          case 0:
            startX += projection.distance[1];
            startY -= projection.distance[0];
            break;
          case 1:
            startX += projection.distance[0];
            startY += projection.distance[1];
            break;
          case 2:
            startX -= projection.distance[1];
            startY += projection.distance[0];
            break;
          case 3:
            startX -= projection.distance[0];
            startY -= projection.distance[1];
            break;
        }
        const projected = [];
        for (const row in projection.grid) {
          const columns = projection.grid[row];
          for (const column in columns) {
            const targeted = projection.grid[row][column];
            if (targeted) {
              let axe;
              switch (direction) {
                case 0:
                  axe = [column, row];
                  break;
                case 1:
                  axe = [-row, column];
                  break;
                case 2:
                  axe = [-column, -row];
                  break;
                case 3:
                  axe = [row, -column];
                  break;
              }
              const x = startX + parseInt(axe[0]);
              const y = startY + parseInt(axe[1]);
              if (x < 0 || y < 0 || x >= layer.area.x || y >= layer.area.y) {
                continue;
              }
              projected.push({x, y});
            }
          }
        }
        return projected;
      }
      get qty() {
        return slots[this.slot].qty;
      }
      set qty(qty) {
        if (qty <= 0) {
          Component.markChange(instance.entity, 'slotChange', {[this.slot]: false});
          delete slots[this.slot];
        }
        else {
          slots[this.slot].qty = qty;
          Component.markChange(instance.entity, 'slotChange', {[this.slot]: {qty}});
        }
      }
    }

    for (const slot in slots) {
      const chars = await readAsset([slots[slot].source, 'item.json'].join('/'))
      const json = chars.byteLength > 0
        ? JSON.parse(
          (new TextDecoder()).decode(chars),
        )
        : {};
      instance.$$items[slot] = new ItemProxy(slots, json);
    }
  }
  mergeDiff(original, update) {
    if (!update.slotChange) {
      return super.mergeDiff(original, update);
    }
    const slotChange = {
      ...original.slotChange,
    };
    for (const index in update.slotChange) {
      if (false === update.slotChange[index]) {
        slotChange[index] = false;
      }
      else {
        slotChange[index] = {
          ...slotChange[index],
          ...update.slotChange[index],
        };
      }
    }
    return {slotChange};
  }
  static properties = {
    slots: {
      type: 'map',
      value: {
        type: 'object',
        properties: {
          quantity: {type: 'uint16'},
          source: {type: 'string'},
        },
      },
    },
  };
}