#!/usr/bin/env bash

# Use git-sh-setup, similar to git-rebase
# https://www.kernel.org/pub/software/scm/git/docs/git-sh-setup.html
# https://github.com/git/git/blob/master/git-rebase.sh
# shellcheck disable=SC2034
OPTIONS_STUCKLONG=t
# shellcheck disable=SC2034
OPTIONS_KEEPDASHDASH=
# shellcheck disable=SC2034
OPTIONS_SPEC="\
git open [options]
git open [remote] [branch]
--
  Opens the GitHub page for a repo/branch in your browser.
  https://github.com/paulirish/git-open/

  Available options are
i,issue!      open issues page
"

# https://github.com/koalaman/shellcheck/wiki/SC1090
# shellcheck source=/dev/null
SUBDIRECTORY_OK='Yes' . "$(git --exec-path)/git-sh-setup"

# Defaults
is_issue=0
protocol="https"

while test $# != 0; do
  case "$1" in
  --issue) is_issue=1;;
  --) shift; break ;;
  esac
  shift
done

# are we in a git repo?
if ! git rev-parse --is-inside-work-tree &>/dev/null; then
  echo "Not a git repository." 1>&2
  exit 1
fi

# choose remote. priority to: provided argument, default in config, detected tracked remote, 'origin'
branch_name=$(git name-rev --name-only HEAD 2>/dev/null)
tracked_remote=$(git config "branch.$branch_name.remote")
default_remote=$(git config open.default.remote)
remote=${1:-$default_remote}
remote=${remote:-$tracked_remote}
remote=${remote:-"origin"}

giturl=$(git ls-remote --get-url "$remote")

if [[ -z "$giturl" ]]; then
  echo "Git remote is not set for $remote" 1>&2
  exit 1
fi

# From git-fetch(5), native protocols:
# ssh://[user@]host.xz[:port]/path/to/repo.git/
# git://host.xz[:port]/path/to/repo.git/
# http[s]://host.xz[:port]/path/to/repo.git/
# ftp[s]://host.xz[:port]/path/to/repo.git/
# [user@]host.xz:path/to/repo.git/ - scp-like but is an alternative to ssh.

# Determine whether this is a url (https, ssh, git+ssh...) or an scp-style path
if [[ "$giturl" =~ ^[a-z\+]+://.* ]]; then
  # Trim URL scheme and possible username
  gitprotocol=${giturl%%://*}
  uri=${giturl#*://}
  uri=${uri#*@}

  # Split on first '/ to get server name and path
  domain=${uri%%/*}
  urlpath=${uri#*/}

  # Remove port number from non-http/https protocols (ie, ssh)
  if [[ $gitprotocol != 'https' && $gitprotocol != 'http' ]]; then
    domain=${domain%:*}
  fi
else
  # Trim possible username from SSH path
  uri=${giturl##*@}

  # Split on first ':' to get server name and path
  domain=${uri%%:*}
  urlpath=${uri#*:}
fi

# Trim "/" from beginning of URL; "/" and ".git" from end of URL
urlpath=${urlpath#/} urlpath=${urlpath%/} urlpath=${urlpath%.git}

# If the URL is provided as "http", preserve that
if [[ $gitprotocol == 'http' ]]; then
  protocol='http'
fi

# Allow config options to replace the server or the protocol
openurl="$protocol://$domain"

function getConfig() {
  config=$(git config --get-urlmatch "open.$1" "$openurl")
  echo "${config:-${!1}}"
}

domain=$(getConfig "domain")
protocol=$(getConfig "protocol")

# Get current branch
branch=${2:-$(git symbolic-ref -q --short HEAD)}

# Split arguments on '/'
IFS='/' pathargs=($urlpath)

if (( is_issue )); then
  # For issues, take the numbers and preprend 'issues/'
  providerBranchRef="proxy.php?url=https%3A%2F%2Fgithub.com%2Fissues%2F%24%7Bbranch%2F%2F%5B%5E0-9%5D%2F%7D"
else
  # Make # and % characters url friendly
  #   github.com/paulirish/git-open/pull/24
  branch=${branch//%/%25} branch=${branch//#/%23}
  providerBranchRef="proxy.php?url=https%3A%2F%2Fgithub.com%2Ftree%2F%24branch"
fi

if [[ "$domain" == 'bitbucket.org' ]]; then
  # Bitbucket, see https://github.com/paulirish/git-open/issues/80 for why ?at is needed.
  providerBranchRef="proxy.php?url=https%3A%2F%2Fgithub.com%2Fsrc%3Fat%3D%24branch"
elif [[ "${#pathargs[@]}" -ge 3 && ${pathargs[${#pathargs[@]} - 3]} == 'scm' ]]; then
  # Bitbucket server always has /scm/ as the third to last segment in the url path, e.g. /scm/ppp/test-repo.git
  # Anything before the 'scm' is part of the server's root context

  # If there are other context parts, add them, up to (but not including) the found 'scm'
  pathPref=("${pathargs[*]:0:${#pathargs[@]} - 3}")

  # Replace the 'scm' element, with 'projects'. Keep the first argument, the string 'repos', and finally the rest of the arguments.
  pathargs=(${pathPref[@]} 'projects' ${pathargs[${#pathargs[@]} - 2]} 'repos' "${pathargs[@]:${#pathargs[@]} - 1}")
  IFS='/' urlpath="${pathargs[*]}"
  providerBranchRef="proxy.php?url=https%3A%2F%2Fgithub.com%2Fbrowse%3Fat%3D%24branch"
elif [[ "${#pathargs[@]}" -ge '2' && ${pathargs[${#pathargs[@]} - 2]} == '_git' ]]; then
  # Visual Studio Team Services and Team Foundation Server always have /_git/ as the second to last segment in the url path
  if (( is_issue )); then
    # Switch to workitems, provide work item id if specified
    urlpath="${urlpath%%/_git/*}/_workitems"
    providerBranchRef="proxy.php?url=https%3A%2F%2Fgithub.com%2F%3Fid%3D%24%7Bbranch%2F%2F%5B%5E0-9%5D%2F%7D"
  else
    # Keep project and repository name, append branch selector.
    providerBranchRef="proxy.php?url=https%3A%2F%2Fgithub.com%2F%3Fversion%3DGB%24branch"
  fi
fi

openurl="$protocol://$domain/$urlpath"

# simplify URL for master
if [[ $branch != "master" ]]; then
    openurl="$openurl$providerBranchRef"
fi

# get current open browser command
case $( uname -s ) in
  Darwin)   open='open';;
  MINGW*)   open='start';;
  MSYS*)    open='start';;
  CYGWIN*)  open='cygstart';;
  *)        # Try to detect WSL (Windows Subsystem for Linux)
            if uname -r | grep -q Microsoft; then
              open='powershell.exe'
              openopt='Start'
            else
              open='xdg-open'
            fi;;
esac

# Allow printing the url if BROWSER=echo
if [[ $BROWSER != "echo" ]]; then
  exec &>/dev/null
fi

# open it in a browser
${BROWSER:-$open} $openopt "$openurl"

unset openopt