package s3.website.model

import java.io.File
import s3.website.Push.CliArgs
import s3.website.model.Ssg.autodetectSiteDir

import scala.util.Try
import org.yaml.snakeyaml.Yaml
import s3.website.model.Config._
import scala.io.Source.fromFile
import scala.language.postfixOps
import s3.website.{S3Key, Logger, ErrorReport}
import scala.util.Failure
import s3.website.model.Config.UnsafeYaml
import scala.util.Success

case class Site(rootDirectory: File, config: Config) {
  def resolveS3Key(file: File) = S3Key.build(
    file.getAbsolutePath.replace(rootDirectory.getAbsolutePath, "").replace(File.separator,"/").replaceFirst("^/", ""),
    config.s3_key_prefix
  )
}

object Site {
  def parseConfig(implicit logger: Logger, yamlConfig: S3_website_yml): Either[ErrorReport, Config] = {
    val yamlObjectTry = for {
      yamlString <- Try(fromFile(yamlConfig.file).mkString)
      yamlWithErbEvaluated <- erbEval(yamlString, yamlConfig)
      yamlObject <- Try(new Yaml() load yamlWithErbEvaluated)
    } yield yamlObject

    yamlObjectTry match {
      case Success(yamlObject) =>
        implicit val unsafeYaml = UnsafeYaml(yamlObject)
        for {
          s3_id <- loadOptionalString("s3_id").right
          s3_secret <- loadOptionalString("s3_secret").right
          session_token <- loadOptionalString("session_token").right
          s3_bucket <- loadRequiredString("s3_bucket").right
          s3_endpoint <- loadEndpoint.right
          site <- loadOptionalString("site").right
          max_age <- loadMaxAge.right
          cache_control <- loadCacheControl.right
          gzip <- loadOptionalBooleanOrStringSeq("gzip").right
          gzip_zopfli <- loadOptionalBoolean("gzip_zopfli").right
          extensionless_mime_type <- loadOptionalString("extensionless_mime_type").right
          s3_key_prefix <- loadOptionalString("s3_key_prefix").right
          ignore_on_server <- loadOptionalS3KeyRegexes("ignore_on_server").right
          exclude_from_upload <- loadOptionalS3KeyRegexes("exclude_from_upload").right
          s3_reduced_redundancy <- loadOptionalBoolean("s3_reduced_redundancy").right
          cloudfront_distribution_id <- loadOptionalString("cloudfront_distribution_id").right
          cloudfront_invalidate_root <- loadOptionalBoolean("cloudfront_invalidate_root").right
          content_type <- loadContentType.right
          concurrency_level <- loadOptionalInt("concurrency_level").right
          cloudfront_wildcard_invalidation <- loadOptionalBoolean("cloudfront_wildcard_invalidation").right
          redirects <- loadRedirects(s3_key_prefix).right
          treat_zero_length_objects_as_redirects <- loadOptionalBoolean("treat_zero_length_objects_as_redirects").right
        } yield {
          gzip_zopfli.foreach(_ => logger.info(
            """|Zopfli is not currently supported. Falling back to regular gzip.
              |If you find a stable Java implementation for zopfli, please send an email to lauri.lehmijoki@iki.fi about it."""
              .stripMargin))
          extensionless_mime_type.foreach(_ => logger.info(
            s"Ignoring the extensionless_mime_type setting in $yamlConfig. Counting on Apache Tika to infer correct mime types.")
          )
          Config(
            s3_id,
            s3_secret,
            session_token,
            s3_bucket,
            s3_endpoint getOrElse S3Endpoint.defaultEndpoint,
            site,
            max_age,
            cache_control,
            gzip,
            gzip_zopfli,
            s3_key_prefix,
            ignore_on_server = ignore_on_server,
            exclude_from_upload = exclude_from_upload,
            s3_reduced_redundancy,
            cloudfront_distribution_id,
            cloudfront_invalidate_root,
            content_type,
            redirects,
            concurrency_level.fold(20)(_ max 20),
            cloudfront_wildcard_invalidation,
            treat_zero_length_objects_as_redirects
          )
        }
      case Failure(error) =>
        Left(ErrorReport(error))
    }
  }

  def loadSite(implicit yamlConfig: S3_website_yml, cliArgs: CliArgs, workingDirectory: File, logger: Logger): Either[ErrorReport, Site] =
    parseConfig.right.flatMap { cfg =>
      implicit val config: Config = cfg
      resolveSiteDir.right.map(Site(_, config))
    }

  def noSiteFound(explanation: String) =
    s"""|
        |$explanation
        |Either use the --site=DIR command-line argument or define the location of the site in s3_website.yml.
        |
        |Here's an example of how you can define the site directory in s3_website.yml:
        |   site: dist/website""".stripMargin

  def resolveSiteDir(implicit yamlConfig: S3_website_yml, config: Config, cliArgs: CliArgs, workingDirectory: File): Either[ErrorReport, File] = {
    val siteFromAutoDetect = if (config.site.isEmpty) { autodetectSiteDir(workingDirectory) } else { None }
    val errOrSiteFromCliArgs: Either[ErrorReport, Option[File]] = Option(cliArgs.site) match {
      case Some(siteDirFromCliArgs) =>
        val f = new File(siteDirFromCliArgs)
        if (f.exists())
          Right(Some(f))
        else
          Left(ErrorReport(noSiteFound(s"Could not find a site at $siteDirFromCliArgs. Check the --site argument.")))
      case None => Right(None)
    }

    val errOrAvailableSiteDirs: Either[ErrorReport, List[File]] = for {
      s1 <- errOrSiteFromCliArgs.right
      s2 <- siteFromConfig.right
      s3 <- Right(siteFromAutoDetect).right
    } yield {
      (s1 :: s2 :: s3 :: Nil) collect {
        case Some(file) => file
      }
    }
    errOrAvailableSiteDirs.right.flatMap {
      case mostPreferredSiteDir :: xs => Right(mostPreferredSiteDir)
      case Nil => Left(ErrorReport(noSiteFound("Could not find a website.")))
    }
  }

  def siteFromConfig(implicit yamlConfig: S3_website_yml, config: Config, workingDirectory: File): Either[ErrorReport, Option[File]] = {
    val siteConfig = config
      .site
      .map(new File(_))
      .map { siteDir =>
        if (siteDir.isAbsolute) siteDir
        else new File(yamlConfig.file.getParentFile, siteDir.getPath)
      }

    siteConfig match {
      case s @ Some(siteDir) =>
        if (siteDir.exists())
          Right(s)
        else
          Left(ErrorReport(noSiteFound(s"Could not find a website. (The site setting in s3_website.yml points to a non-existing file $siteDir)")))
      case None =>
        Right(None)
    }
  }
}