export function paginateModels(models) {
  for (let model of models) {
    // ensure sizes
    model.size = modelSize(model)
  }

  let pages = []
  let currentSize = 0
  let currentPage = []
  for (let model of models) {
    if (model.size > 0) { // skip empty models
      currentSize += model.size
      if (currentSize > 3) {
        pages.push(currentPage)
        currentPage = [model]
        currentSize = model.size
      } else {
        currentPage.push(model)
      }
    }
  }
  if (currentPage.length > 0) {
    pages.push(currentPage)
  }

  return pages
}

export function modelSize(model) {
  if (!model || !model.ids) return 0
  if (model.ids.length <= 4) return 1
  if (model.ids.length <= 8) return 2
  return 3
}

export function sectionModels(section) {
  // remove pages, return models (blocks) in order
  let models = []
  if (section && section.pages) {
    for (let page of section.pages) {
      models.push(...page)
    }
  }

  return models
}

export function sectionTitle(material) {
  // "Trailhead (Men)"
  if (material) {
    return `${material.category} (${material.gender})`
  } else {
    return '(unknown)'
  }
}

// add properties from the material to the model,
// creating it if necessary.
export function extendModelFromMaterial(material, model = {}) {
  if (material) {
    if (!model['name']) {
      // don't overwrite possibly overridden value
      model['name'] = material.name
    }
    model['model'] = material.model
    model['family'] = material.family
    model['gender'] = material.gender
    model['category'] = material.category

    // make sure the material id is in the list
    let ids = model['ids'] || []
    if (!ids.includes(material.id)) {
      ids.push(material.id)
      model['ids'] = ids
    }
  }

  return model
}