'use strict'

const directiveParser = require('./directive-parser.js')

module.exports = {
  stack: [],
  pop (current) {
    const index = this.stack.indexOf(current)
    if (index !== -1) {
      this.stack.splice(index, 1)
    }

    if (!current.preserve) {
      current.source.remove()
    }
  },
  parse (node, lazyResult, callback) {
    let current
    const metadata = directiveParser(node)
    if (metadata) {
      if (!metadata.begin && metadata.end) {
        this.walk((item) => {
          if (metadata.name === item.metadata.name) {
            this.pop(item)
            current = { metadata, directive: item.directive, source: node, preserve: item.preserve }
            return false
          }
        })
      } else {
        current = { metadata, directive: null, source: node, preserve: null }
      }

      if (current === undefined) {
        lazyResult.warn(`found end "${metadata.name}" without a matching begin.`, { node: node })
      } else if (callback(current)) {
        this.stack.push(current)
      } else if (!current.preserve) {
        current.source.remove()
      }
    }
  },
  walk (callback) {
    let len = this.stack.length
    while (--len > -1) {
      if (!callback(this.stack[len])) {
        break
      }
    }
  }
}