package service

import java.io.File
import java.util.Date
import org.eclipse.jgit.api.Git
import org.apache.commons.io.FileUtils
import util.{Directory, JGitUtil, LockUtil}
import util.ControlUtil._

object WikiService {
  
  /**
   * The model for wiki page.
   * 
   * @param name the page name
   * @param content the page content
   * @param committer the last committer
   * @param time the last modified time
   */
  case class WikiPageInfo(name: String, content: String, committer: String, time: Date)
  
  /**
   * The model for wiki page history.
   * 
   * @param name the page name
   * @param committer the committer the committer
   * @param message the commit message
   * @param date the commit date
   */
  case class WikiPageHistoryInfo(name: String, committer: String, message: String, date: Date)

}

trait WikiService {
  import WikiService._

  def createWikiRepository(loginAccount: model.Account, owner: String, repository: String): Unit =
    LockUtil.lock(s"${owner}/${repository}/wiki"){
      defining(Directory.getWikiRepositoryDir(owner, repository)){ dir =>
        if(!dir.exists){
          try {
            JGitUtil.initRepository(dir)
            saveWikiPage(owner, repository, "Home", "Home", s"Welcome to the ${repository} wiki!!", loginAccount, "Initial Commit")
          } finally {
            // once delete cloned repository because initial cloned repository does not have 'branch.master.merge'
            FileUtils.deleteDirectory(Directory.getWikiWorkDir(owner, repository))
          }
        }
      }
    }

  /**
   * Returns the wiki page.
   */
  def getWikiPage(owner: String, repository: String, pageName: String): Option[WikiPageInfo] = {
    using(Git.open(Directory.getWikiRepositoryDir(owner, repository))){ git =>
      optionIf(!JGitUtil.isEmpty(git)){
        JGitUtil.getFileList(git, "master", ".").find(_.name == pageName + ".md").map { file =>
          WikiPageInfo(file.name, new String(git.getRepository.open(file.id).getBytes, "UTF-8"), file.committer, file.time)
        }
      }
    }
  }

  /**
   * Returns the content of the specified file.
   */
  def getFileContent(owner: String, repository: String, path: String): Option[Array[Byte]] =
    using(Git.open(Directory.getWikiRepositoryDir(owner, repository))){ git =>
      optionIf(!JGitUtil.isEmpty(git)){
        val index = path.lastIndexOf('/')
        val parentPath = if(index < 0) "."  else path.substring(0, index)
        val fileName   = if(index < 0) path else path.substring(index + 1)

        JGitUtil.getFileList(git, "master", parentPath).find(_.name == fileName).map { file =>
          git.getRepository.open(file.id).getBytes
        }
      }
    }

  /**
   * Returns the list of wiki page names.
   */
  def getWikiPageList(owner: String, repository: String): List[String] = {
    using(Git.open(Directory.getWikiRepositoryDir(owner, repository))){ git =>
      JGitUtil.getFileList(git, "master", ".")
        .filter(_.name.endsWith(".md"))
        .map(_.name.replaceFirst("\\.md$", ""))
        .sortBy(x => x)
    }
  }
  
  /**
   * Save the wiki page.
   */
  def saveWikiPage(owner: String, repository: String, currentPageName: String, newPageName: String,
      content: String, committer: model.Account, message: String): Option[String] = {

    LockUtil.lock(s"${owner}/${repository}/wiki"){
      defining(Directory.getWikiWorkDir(owner, repository)){ workDir =>
        // clone working copy
        cloneOrPullWorkingCopy(workDir, owner, repository)

        // write as file
        using(Git.open(workDir)){ git =>
          defining(new File(workDir, newPageName + ".md")){ file =>
            val added = executeIf(!file.exists || FileUtils.readFileToString(file, "UTF-8") != content){
              FileUtils.writeStringToFile(file, content, "UTF-8")
              git.add.addFilepattern(file.getName).call
            }

            // delete file
            val deleted = executeIf(currentPageName != "" && currentPageName != newPageName){
              git.rm.addFilepattern(currentPageName + ".md").call
            }

            // commit and push
            optionIf(added || deleted){
              defining(git.commit.setCommitter(committer.userName, committer.mailAddress).setMessage(message).call){ commit =>
                git.push.call
                Some(commit.getName)
              }
            }
          }
        }
      }
    }
  }

  /**
   * Delete the wiki page.
   */
  def deleteWikiPage(owner: String, repository: String, pageName: String,
                     committer: String, mailAddress: String, message: String): Unit = {
    LockUtil.lock(s"${owner}/${repository}/wiki"){
      defining(Directory.getWikiWorkDir(owner, repository)){ workDir =>
        // clone working copy
        cloneOrPullWorkingCopy(workDir, owner, repository)

        // delete file
        new File(workDir, pageName + ".md").delete

        using(Git.open(workDir)){ git =>
          git.rm.addFilepattern(pageName + ".md").call

          // commit and push
          git.commit.setAuthor(committer, mailAddress).setMessage(message).call
          git.push.call
        }
      }
    }
  }

  private def cloneOrPullWorkingCopy(workDir: File, owner: String, repository: String): Unit = {
    if(!workDir.exists){
      Git.cloneRepository
        .setURI(Directory.getWikiRepositoryDir(owner, repository).toURI.toString)
        .setDirectory(workDir)
        .call
        .getRepository
        .close
    } else using(Git.open(workDir)){ git =>
      git.pull.call
    }
  }

}