We-Eat/server/app/com/weEat/controllers/ParserController.scala

package com.weEat.controllers

import com.weEat.shared.models._
import javax.inject.{Inject,Singleton}
import play.api.libs.json._
import play.api.mvc._
import scala.concurrent.Future
import com.weEat.models.Authorization
import scalaoauth2.provider.{AuthInfoRequest,OAuth2ProviderActionBuilders}
import com.weEat.services.OAuth2Service
import net.ruippeixotog.scalascraper.browser.JsoupBrowser
import net.ruippeixotog.scalascraper.dsl.DSL._
import net.ruippeixotog.scalascraper.dsl.DSL.Extract._
import net.ruippeixotog.scalascraper.model.Element
import net.ruippeixotog.scalascraper.scraper.HtmlExtractor

@Singleton
class ParserController @Inject()(
  val controllerComponents: ControllerComponents,
  oauth: OAuth2Service,
  usdaController: USDAController,
  foodController: FoodController
) extends BaseController
    with OAuth2ProviderActionBuilders {
  implicit val ec = scala.concurrent.ExecutionContext.global

  private val _browser = JsoupBrowser()

  def parseURL() = AuthorizedAction[Authorization](oauth).async(parse.text)({ implicit request: AuthInfoRequest[String, Authorization] =>
    val url = request.body
    _findParser(url).fold(Future.successful(NotFound(s"No parser available for $url."))) { (parser) =>
      val doc = _browser.get(url)
      val title = doc >> parser.titleExtractor
      val servings = doc >> parser.servingExtractor
      val prepTime = parser.prepTimeExtractor.map(doc >> _)
      val cookTime = parser.cookTimeExtractor.map(doc >> _)
      val ingredients = doc >> parser.ingredientExtractor
      val instructions = doc >> parser.instructionExtractor

      Future.sequence(ingredients.map(_parseIngredient _))
        .map((ingredients) => Ok(Json.toJson(RecipeNodeNoId(
          title,
          servings.getOrElse(1.0f),
          1.0f,
          UnitType.NUMBER,
          ingredients.toSeq,
          /* tflucke@[2023-10-26]: Do not pss along the instructions since this
           * could be a violation of the Recipe Author's copyright. */
          Nil, //instructions.toSeq,
          None,
          None,
          Some(url)
        ))))
    }
  })

  private def _findParser(url: String): Option[Parser] = {
    val host = new java.net.URL(url).getAuthority()
    val hostNoWWW = if (host.startsWith("www.")) host.substring("www.".length) else host
    Map(
      ("epicurious.com" -> Parser.epicurious),
      ("mccormick.com" -> Parser.mccormick)
    ).get(hostNoWWW)
  }

  private def _parseIngredient(ingredientLine: String): Future[Ingredient] = {
    val numberPattern = raw"(\d+)[\d-_]*\s(\w+)\s+(.+)".r
    val fractionPattern = raw"(\d+)/(\d+)[\d-_]*\s(\w+)\s+(.+)".r

    ingredientLine match {
      case numberPattern(amount, unit, rest) =>
        _guessFoodFromStr(rest).map(Ingredient(_, amount.toFloat, MeasureUnit.guessUnit(unit).getOrElse(Count)))
      case fractionPattern(numerator, denominator, unit, rest) =>
        _guessFoodFromStr(rest).map(Ingredient(_, numerator.toFloat/denominator.toFloat, MeasureUnit.guessUnit(unit).getOrElse(Count)))
      case noUnitLine => _guessFoodFromStr(noUnitLine).map(Ingredient(_, 1, Count))
    }

  }

  private def _guessFoodFromStr(foodLine: String): Future[Ingredient.IngredientId] = {
    import gov.usda.nal.fdc.models.DataType._
    usdaController.fdc.getFoodsSearch(foodLine, Seq(
      Foundation, Survey, SRLegacy
    ), pageSize = Some(10))().flatMap({ (fdcResult) =>
      Future.sequence(fdcResult.foods.map((food) => foodController.getByFdcId(food.fdcId)))
        .map(_.flatten
          .headOption
          .fold[Ingredient.IngredientId](Ingredient.USDAId(fdcResult.foods.head.fdcId))((foodNode) => Ingredient.FoodNodeId(foodNode._id))
        )
    })
  }
}

case class Parser(
  titleExtractor: HtmlExtractor[Element, String],
  servingExtractor: HtmlExtractor[Element, Option[Float]],
  prepTimeExtractor: Option[HtmlExtractor[Element, String]],
  cookTimeExtractor: Option[HtmlExtractor[Element, String]],
  ingredientExtractor: HtmlExtractor[Element, Iterable[String]],
  instructionExtractor: HtmlExtractor[Element, Iterable[String]],
)

object Parser {
  val mccormick = Parser(
    text("h1"),
    text(".main-title .count").map(_.toFloatOption),
    Some(text(".prep_time .first_content")),
    cookTimeExtractor = Some(text(".ingredients .first_content")),
    ingredientExtractor = texts(".recipe-about-list li"),
    texts(".instructions-main span.para")
  )
  val epicurious = Parser(
    text("h1"),
    text("""div[data-testid="IngredientList"] > p""").map("Yield: \\D*(\\d+).*".r.findFirstMatchIn(_).map(_.group(1).toFloat)),
    None,
    None,
    texts("""div[data-testid="IngredientList"] > div > div"""),
    texts("""div[data-testid="InstructionsWrapper"] > ol > li > p""")
  )
}