#!/bin/bash

#
# git recent 2.0 - switching branches, but so fancy
#
# - view recently edited local branches
# - see unique commits to that branch, and optionally the branch diff (against the main/master/primary branch) with Ctrl-o
# - hit Enter to checkout the selected branch.
# - text filtering against branch names, too.
#

if ! command -v fzf >/dev/null 2>&1; then
  echo "Error: fzf is not installed. Please install fzf to use git-recent." >&2
  exit 1
fi
[ "$(git rev-parse --is-inside-work-tree)" = "true" ] || exit

if [[ "$1" == "--help" ]]; then
  echo "git-recent: Browse and checkout recently used Git branches."
  echo
  echo "Keybindings:"
  echo "  Enter:      Checkout the selected branch"
  echo "  Ctrl-O:     Show the diff of the selected branch against the main/master branch"
  echo "  Ctrl-C:     Exit"
  exit 0
fi

# ---------------------------------------------------------------------------------------

# The HEAD of the primary branch (eg main or master or w/e), for diffing.
# TODO: some branch mgmt approaches don't work well with this. And may prefer `git log --pretty=format:%H --merges -n 1`.  See https://github.com/paulirish/git-recent/issues/28
diff_base=$(cat $(git rev-parse --show-cdup).git/refs/remotes/origin/HEAD | awk '{print $2}')

# Extract branch name (without any trailing text, like the Chromium link)
define_branchname="branchname=\\\$(echo {1} | cut -d' ' -f1)"

# Colorized hash, author, date, then commit subject followed by commit message body (wrapped and indented).
commits_format="%C(red bold)%h %C(bold blue)%an %C(bold green)%ad %Creset%s%w(0,4,4)%+b%w(0,0,0)"
uniqcommits_cmd="sh -c \"$define_branchname; git log --date=human --color=always --format='$commits_format' --no-merges $diff_base..\\\$branchname\""

# Progressive enhancement if you have delta or diff-so-fancy
diff_pager_cmd=$(command -v delta || command -v diff-so-fancy)
pipe_to_pager=${diff_pager_cmd:+" | $diff_pager_cmd"}
diffbranch_cmd="sh -c \"$define_branchname; git diff --color=always $diff_base...\\\$branchname $pipe_to_pager\""

# Copy to clipboard, variants for mac/linux
copy_cmd="echo 'Could not copy {} to clipboard.'"
if command -v pbcopy >/dev/null; then
  copy_cmd="printf '%s' {} | pbcopy"
elif command -v wl-copy >/dev/null; then
  copy_cmd="printf '%s' {} | wl-copy"
elif command -v xclip >/dev/null; then
  copy_cmd="printf '%s' {} | xclip -selection clipboard"
elif command -v xsel >/dev/null; then
  copy_cmd="printf '%s' {} | xsel --clipboard"
fi

YELLOW='\033[0;33m'
DIM='\033[2m'
NC='\033[0m' # No Color

# if show_cl passed then also run git cl status. (chromium repos)
[[ "$1" == "--cl" || "$1" == "-cl" ]] && show_cl=true || show_cl=false

# if extra arg passed (eg `git recent remotename`), then list those remote branches, rather than local ones
[[ -n "$1" && "$show_cl" != true ]] && heads="refs/remotes/$1" || heads="refs/heads"


# fzf git inspiration:
# - https://github.com/junegunn/fzf/wiki/Examples#git
# - https://github.com/junegunn/fzf/wiki/Examples-(fish)#git
# - https://github.com/junegunn/fzf-git.sh (intense.)

# If there's a GIT_RECENT_QUERY environment variable, use it for non-interactive filtering. (Primarily added for testing: https://github.com/Homebrew/homebrew-core/blob/HEAD/Formula/g/git-recent.rb#L41-L46)
filterarg=${GIT_RECENT_QUERY:+"--filter=$GIT_RECENT_QUERY"}

# Check fzf version for preview scroll keys support (introduced in 0.23.0)
fzf_version=$(fzf --version | awk '{print $1}')
fzf_scroll_binds=""
if [[ $(printf '%s\n0.23.0\n' "$fzf_version" | sort -V | head -n1) == "0.23.0" ]]; then
  fzf_scroll_binds="--bind 'preview-scroll-up:preview-up+preview-up+preview-up' --bind 'preview-scroll-down:preview-down+preview-down+preview-down'"
fi

# Chromium hackers may want reference to their relevant CL.
CL_STATUS=$([ "$show_cl" = true ] && git cl status --fast --no-branch-color | grep 'https://' | sed 's| (.*||')

_browse_branches() {
  git for-each-ref --sort=-authordate "$heads" --format="%(refname:short)" \
    | while read -r branch_name; do
        if [ "$show_cl" != true ]; then
          printf "$YELLOW%s$NC\n" "$branch_name"
          continue
        fi
        review_url=$(echo "$CL_STATUS" | grep -E "\b${branch_name} :" | grep -o -E 'https://.*' | sed 's|https://||')
        # Using fancy integrated hyperlinks: https://iterm2.com/feature-reporting/Hyperlinks_in_Terminal_Emulators.html
        # TODO: maybe get rid of the crrev.com/c/ text as the link?
        # TODO: use `git config branch.$(git rev-parse --abbrev-ref HEAD).gerritissue` and gerritserver to avoid using `git cl status`
        printf "$YELLOW%s $DIM\033]8;;%s\a%s\033]8;;\a$NC\n" "$branch_name" "https://$review_url" "$review_url"
      done \
    | fzf  \
        $filterarg --ansi -- --layout=reverse --multi --height=90% --min-height=20  \
        --border-label-pos=2 --border-label '🌲 Branches' --border \
        --no-hscroll --no-multi \
        --preview-window='right,70%,border-left,border-rounded' --preview="$uniqcommits_cmd" --preview-label="Commits unique to branch" \
        --header $'ENTER (checkout)\nCTRL-O (show branch diff)\nCTRL-Y (copy name to clipboard)' \
        $fzf_scroll_binds \
        --bind "ctrl-y:execute-silent($copy_cmd)" \
        --bind "ctrl-o:preview:$diffbranch_cmd"
}
output="$(_browse_branches)"
line_count=$(printf "%s" "$output" | wc -l)

if [[ -n "$output" ]] && (( line_count == 0 )); then
  chosen_branch=$(echo "$output" | cut -d' ' -f1)
  echo git checkout "$chosen_branch"
  git checkout "$chosen_branch"
else
  echo "$output"
fi