import { ResolveOptions, resolve } from './util'
import { NodeAnchor } from './index'
import { Point } from '../../geometry'

export interface MiddleSideEndpointOptions extends ResolveOptions {
  rotate?: boolean
  padding?: number
  direction?: 'H' | 'V'
}

const middleSide: NodeAnchor.ResolvedDefinition<MiddleSideEndpointOptions> =
  function (view, magnet, refPoint, options) {
    let bbox
    let angle = 0
    let center

    const node = view.cell
    if (options.rotate) {
      bbox = view.getUnrotatedBBoxOfElement(magnet)
      center = node.getBBox().getCenter()
      angle = node.getAngle()
    } else {
      bbox = view.getBBoxOfElement(magnet)
    }

    const padding = options.padding
    if (padding != null && Number.isFinite(padding)) {
      bbox.inflate(padding)
    }

    if (options.rotate) {
      refPoint.rotate(angle, center)
    }

    const side = bbox.getNearestSideToPoint(refPoint)
    let result: Point
    switch (side) {
      case 'left':
        result = bbox.getLeftMiddle()
        break
      case 'right':
        result = bbox.getRightMiddle()
        break
      case 'top':
        result = bbox.getTopCenter()
        break
      case 'bottom':
        result = bbox.getBottomCenter()
        break
      default:
        break
    }

    const direction = options.direction
    if (direction === 'H') {
      if (side === 'top' || side === 'bottom') {
        if (refPoint.x <= bbox.x + bbox.width) {
          result = bbox.getLeftMiddle()
        } else {
          result = bbox.getRightMiddle()
        }
      }
    } else if (direction === 'V') {
      if (refPoint.y <= bbox.y + bbox.height) {
        result = bbox.getTopCenter()
      } else {
        result = bbox.getBottomCenter()
      }
    }

    return options.rotate ? result!.rotate(-angle, center) : result!
  }

/**
 * Places the anchor of the edge in the middle of the side of view bbox
 * closest to the other endpoint.
 */
export const midSide = resolve<
  NodeAnchor.ResolvedDefinition<ResolveOptions>,
  NodeAnchor.Definition<ResolveOptions>
>(middleSide)