import * as core from '@actions/core'
import * as fsHelper from './fs-helper'
import * as gitAuthHelper from './git-auth-helper'
import * as gitCommandManager from './git-command-manager'
import * as gitDirectoryHelper from './git-directory-helper'
import * as githubApiHelper from './github-api-helper'
import * as io from '@actions/io'
import * as path from 'path'
import * as refHelper from './ref-helper'
import * as stateHelper from './state-helper'
import * as urlHelper from './url-helper'
import {IGitCommandManager} from './git-command-manager'
import {IGitSourceSettings} from './git-source-settings'

export async function getSource(settings: IGitSourceSettings): Promise<void> {
  // Repository URL
  core.info(
    `Syncing repository: ${settings.repositoryOwner}/${settings.repositoryName}`
  )
  const repositoryUrl = urlHelper.getFetchUrl(settings)

  // Remove conflicting file path
  if (fsHelper.fileExistsSync(settings.repositoryPath)) {
    await io.rmRF(settings.repositoryPath)
  }

  // Create directory
  let isExisting = true
  if (!fsHelper.directoryExistsSync(settings.repositoryPath)) {
    isExisting = false
    await io.mkdirP(settings.repositoryPath)
  }

  // Git command manager
  core.startGroup('Getting Git version info')
  const git = await getGitCommandManager(settings)
  core.endGroup()

  let authHelper: gitAuthHelper.IGitAuthHelper | null = null
  try {
    if (git) {
      authHelper = gitAuthHelper.createAuthHelper(git, settings)
      await authHelper.configureTempGlobalConfig()
    }

    // Prepare existing directory, otherwise recreate
    if (isExisting) {
      await gitDirectoryHelper.prepareExistingDirectory(
        git,
        settings.repositoryPath,
        repositoryUrl,
        settings.clean,
        settings.ref
      )
    }

    if (!git) {
      // Downloading using REST API
      core.info(`The repository will be downloaded using the GitHub REST API`)
      core.info(
        `To create a local Git repository instead, add Git ${gitCommandManager.MinimumGitVersion} or higher to the PATH`
      )
      if (settings.submodules) {
        throw new Error(
          `Input 'submodules' not supported when falling back to download using the GitHub REST API. To create a local Git repository instead, add Git ${gitCommandManager.MinimumGitVersion} or higher to the PATH.`
        )
      } else if (settings.sshKey) {
        throw new Error(
          `Input 'ssh-key' not supported when falling back to download using the GitHub REST API. To create a local Git repository instead, add Git ${gitCommandManager.MinimumGitVersion} or higher to the PATH.`
        )
      }

      await githubApiHelper.downloadRepository(
        settings.authToken,
        settings.repositoryOwner,
        settings.repositoryName,
        settings.ref,
        settings.commit,
        settings.repositoryPath
      )
      return
    }

    // Save state for POST action
    stateHelper.setRepositoryPath(settings.repositoryPath)

    // Initialize the repository
    if (
      !fsHelper.directoryExistsSync(path.join(settings.repositoryPath, '.git'))
    ) {
      core.startGroup('Initializing the repository')
      await git.init()
      await git.remoteAdd('origin', repositoryUrl)
      core.endGroup()
    }

    // Disable automatic garbage collection
    core.startGroup('Disabling automatic garbage collection')
    if (!(await git.tryDisableAutomaticGarbageCollection())) {
      core.warning(
        `Unable to turn off git automatic garbage collection. The git fetch operation may trigger garbage collection and cause a delay.`
      )
    }
    core.endGroup()

    // If we didn't initialize it above, do it now
    if (!authHelper) {
      authHelper = gitAuthHelper.createAuthHelper(git, settings)
    }
    // Configure auth
    core.startGroup('Setting up auth')
    await authHelper.configureAuth()
    core.endGroup()

    // Determine the default branch
    if (!settings.ref && !settings.commit) {
      core.startGroup('Determining the default branch')
      if (settings.sshKey) {
        settings.ref = await git.getDefaultBranch(repositoryUrl)
      } else {
        settings.ref = await githubApiHelper.getDefaultBranch(
          settings.authToken,
          settings.repositoryOwner,
          settings.repositoryName
        )
      }
      core.endGroup()
    }

    // LFS install
    if (settings.lfs) {
      await git.lfsInstall()
    }

    // Fetch
    core.startGroup('Fetching the repository')
    if (settings.fetchDepth <= 0) {
      // Fetch all branches and tags
      let refSpec = refHelper.getRefSpecForAllHistory(
        settings.ref,
        settings.commit
      )
      await git.fetch(refSpec)

      // When all history is fetched, the ref we're interested in may have moved to a different
      // commit (push or force push). If so, fetch again with a targeted refspec.
      if (!(await refHelper.testRef(git, settings.ref, settings.commit))) {
        refSpec = refHelper.getRefSpec(settings.ref, settings.commit)
        await git.fetch(refSpec)
      }
    } else {
      const refSpec = refHelper.getRefSpec(settings.ref, settings.commit)
      await git.fetch(refSpec, settings.fetchDepth)
    }
    core.endGroup()

    // Checkout info
    core.startGroup('Determining the checkout info')
    const checkoutInfo = await refHelper.getCheckoutInfo(
      git,
      settings.ref,
      settings.commit
    )
    core.endGroup()

    // LFS fetch
    // Explicit lfs-fetch to avoid slow checkout (fetches one lfs object at a time).
    // Explicit lfs fetch will fetch lfs objects in parallel.
    if (settings.lfs) {
      core.startGroup('Fetching LFS objects')
      await git.lfsFetch(checkoutInfo.startPoint || checkoutInfo.ref)
      core.endGroup()
    }

    // Checkout
    core.startGroup('Checking out the ref')
    await git.checkout(checkoutInfo.ref, checkoutInfo.startPoint)
    core.endGroup()

    // Submodules
    if (settings.submodules) {
      // Temporarily override global config
      core.startGroup('Setting up auth for fetching submodules')
      await authHelper.configureGlobalAuth()
      core.endGroup()

      // Checkout submodules
      core.startGroup('Fetching submodules')
      await git.submoduleSync(settings.nestedSubmodules)
      await git.submoduleUpdate(settings.fetchDepth, settings.nestedSubmodules)
      await git.submoduleForeach(
        'git config --local gc.auto 0',
        settings.nestedSubmodules
      )
      core.endGroup()

      // Persist credentials
      if (settings.persistCredentials) {
        core.startGroup('Persisting credentials for submodules')
        await authHelper.configureSubmoduleAuth()
        core.endGroup()
      }
    }

    // Get commit information
    const commitInfo = await git.log1()

    // Log commit sha
    await git.log1("--format='%H'")

    // Check for incorrect pull request merge commit
    await refHelper.checkCommitInfo(
      settings.authToken,
      commitInfo,
      settings.repositoryOwner,
      settings.repositoryName,
      settings.ref,
      settings.commit
    )
  } finally {
    // Remove auth
    if (authHelper) {
      if (!settings.persistCredentials) {
        core.startGroup('Removing auth')
        await authHelper.removeAuth()
        core.endGroup()
      }
      authHelper.removeGlobalConfig()
    }
  }
}

export async function cleanup(repositoryPath: string): Promise<void> {
  // Repo exists?
  if (
    !repositoryPath ||
    !fsHelper.fileExistsSync(path.join(repositoryPath, '.git', 'config'))
  ) {
    return
  }

  let git: IGitCommandManager
  try {
    git = await gitCommandManager.createCommandManager(repositoryPath, false)
  } catch {
    return
  }

  // Remove auth
  const authHelper = gitAuthHelper.createAuthHelper(git)
  try {
    await authHelper.configureTempGlobalConfig(repositoryPath)
    await authHelper.removeAuth()
  } finally {
    await authHelper.removeGlobalConfig()
  }
}

async function getGitCommandManager(
  settings: IGitSourceSettings
): Promise<IGitCommandManager | undefined> {
  core.info(`Working directory is '${settings.repositoryPath}'`)
  try {
    return await gitCommandManager.createCommandManager(
      settings.repositoryPath,
      settings.lfs
    )
  } catch (err) {
    // Git is required for LFS
    if (settings.lfs) {
      throw err
    }

    // Otherwise fallback to REST API
    return undefined
  }
}