import { canvas, ctx } from './canvas'
import { Item, ItemTool, ItemStack, MAX_STACK_SIZE } from './items'

const SLOT_SIZE = 32

class Inventory {
  constructor (size) {
    this.size = size
    this.items = []
    this.selected = 0
  }

  addItem (i) {
    if (typeof i === 'string' || i instanceof Item) i = ItemStack.new(i)
    let addedTo = false
    let leftover = null
    for (let k in this.items) {
      if (addedTo) break
      let itm = this.items[k]
      if (itm.name === i.name || itm.isEmpty()) {
        if (itm.isEmpty()) itm.item = i.item
        let addedCount = itm.count + i.count
        if (addedCount > MAX_STACK_SIZE) {
          let m = addedCount - MAX_STACK_SIZE
          let n = itm.copy()
          n.count = m
          itm.count = MAX_STACK_SIZE
          if (this.items.length >= this.size) {
            leftover = n
            addedTo = true
          } else {
            continue
          }
        } else {
          itm.count += i.count
          addedTo = true
        }
      }
    }

    if (!addedTo) {
      if (this.items.length >= this.size) {
        return i
      }
      this.items.push(i)
    }

    return leftover
  }

  getItem (slot) {
    if (this.isEmpty(slot)) return null
    return this.items[slot]
  }

  takeItem (slot, count) {
    if (this.isEmpty(slot)) return null
    let i = this.items[slot]
    if (!count || count > i.count) return i
    i.count -= count
    let copied = i.copy()
    copied.count = count
    return copied
  }

  isEmpty (slot) {
    if (!this.items[slot] || this.items[slot].isEmpty()) return true
    return false
  }

  draw () {
    for (let i = 0; i < this.size; i++) {
      let stack = this.items[i]
      let x = canvas.width / 2 + i * (SLOT_SIZE + 8) - this.size / 2 * SLOT_SIZE
      ctx.fillStyle = (this.selected === i) ? '#f00' : '#ddd'
      ctx.fillRect(x, 16, SLOT_SIZE, SLOT_SIZE)
      if (!stack || stack.isEmpty()) continue
      ctx.drawImage(stack.item.image, x, 16, SLOT_SIZE, SLOT_SIZE)
      if (stack.item instanceof ItemTool) continue
      ctx.font = '16px sans'
      let measure = ctx.measureText(stack.count)
      ctx.fillStyle = '#000'
      ctx.fillText(stack.count, x + SLOT_SIZE / 2 - measure.width / 2, 8 + SLOT_SIZE)
      ctx.fillStyle = '#fff'
      ctx.fillText(stack.count, x + SLOT_SIZE / 2 - measure.width / 2 + 1, 8 + SLOT_SIZE + 1)
    }
  }
}

export { Inventory }