fzgit

#!/usr/bin/env bash

declare -A aliases
declare -A helptext
declare -r c_reset=$(tput sgr0)
declare -r c_red=$(tput setaf 1)
declare -r c_green=$(tput setaf 2)
declare -r c_yellow=$(tput setaf 3)
declare -r c_grey=$(tput setaf 8)

err() {
  printf "${c_red}%s${c_reset}\n" "$*" >&2
}

die() {
  if (($# > 0)); then
    err "$@"
  fi
  exit 1
}

export COLUMNS

has() {
  local v c
  if [[ $1 = '-v' ]]; then
    v=1
    shift
  fi
  for c; do
    c="${c%% *}"
    if ! command -v "$c" &>/dev/null; then
      ((v > 0)) && err "$c not found"
      return 1
    fi
  done
}

select_from() {
  local cmd='command -v'
  for a in "$@"; do
    case "$a" in
    -c)
      cmd="$2"
      shift 2
      ;;
    esac
  done
  for c in "$@"; do
    if $cmd "${c%% *}" &>/dev/null; then
      echo "$c"
      return 0
    fi
  done
  return 1
}

aliases[-h]=help
aliases[--help]=help
helptext[help]='show this help'
subcmd_help() {
  local formattedhelptext

  formattedhelptext=$(for c in "${subcmds_avail[@]}"; do
    printf "  %s\n    %s\n" "$c" "${helptext[$c]}"
  done)
  LESS=-FEXR less <<-HELP
$0 <COMMAND>

${formattedhelptext}
HELP
}

basedir=$(basename $(git rev-parse --show-toplevel))

# TODO: customization?
branch_prefix='  '
separator=' ❯ '

diffprg=$(select_from 'delta -w ${FZF_PREVIEW_COLUMNS:-$COLUMNS}' 'bat --color=always -p' diff-so-fancy diff-highlight colordiff cat)

fzf() {
  local prompt
  if [[ $1 == --prompt=* ]]; then
    prompt="${1##*=}${separator}"
    shift
  fi
  branch=$(__current_branch)
  opts=(--prompt="${basedir}${branch_prefix}${branch}${separator}${prompt}")
  command fzf $FZGIT_FZF_OPTS \
    --inline-info \
    --ansi \
    "$@"
}

__current_branch() {
  git name-rev --name-only HEAD
}

helptext[diff]='Show changes between commits, commit and working tree, etc'
subcmd_diff() {
  local listcmd="diff_histogram $*"
  local diffcmd="git diff $*"
  local statcmd="git diff --shortstat $*"

  while :; do
    watcher
    curl -s --unix-socket /tmp/fzgit.sock http -d "reload($listcmd)+change-header($($statcmd))"
  done &
  listener_pid=$!

  SHELL=bash fzf --prompt='diff $*' \
    -d│ \
    --listen=/tmp/fzgit.sock \
    --header="$($statcmd)" \
    --bind="start:reload:$listcmd" \
    --nth=2.. \
    --preview="$diffcmd -- {1} | $diffprg" \
    --bind='ctrl-p:toggle-preview' \
    --bind="enter:execute:$diffcmd -- {1} | $diffprg | less -R" \
    --preview-window=70%,down
}

helptext[rebase]='Reapply commits on top of another base tip'
subcmd_rebase() {
  if (($# > 0)); then
    git rebase "$@"
    return
  fi
  local commit
  commit=$(
    git log \
      --color=always \
      --pretty=format:$'%h\t%C(dim yellow)%ar%C(reset)\t%s' "$@" |
      fzf --prompt='rebase' \
        --preview='git show --color=always {1}' \
        --accept-nth=1
  )
  [[ -z $commit ]] && return
  git rebase -i "$commit"
}

helptext[add]='Add file contents to the index'
subcmd_add() {
  if (($# > 0)); then
    git add "$@"
    return
  fi
  # TODO: split and make patches smaller
  local listcmd="git diff --color=always | perl -pwe 's/^(\e\[[0-9;]*m)*(?=diff)/\0/m'"

  while :; do
    watcher
    curl -s --unix-socket /tmp/fzgit.sock http -d "reload($listcmd)"
  done &
  listener_pid=$!

  local diff
  diff=$(SHELL=bash fzf \
    --prompt='add' \
    --disabled \
    --read0 \
    --listen=/tmp/fzgit.sock \
    --bind="start:reload:$listcmd" \
    --header='enter:stage | s:split patch' \
    --expect=s \
    --preview='git diff --staged | git apply --stat; git diff --staged --color=always')
  [[ -z $diff ]] && return
  if [[ $diff = s* ]]; then
    split_patch <<<"${diff:2}"
  else
    # elif [[ $diff = a* ]]; then
    patch="${diff:2}"
    git apply --check --cached <<<"$patch" &&
      git apply --cached <<<"$patch"
  fi
  subcmd_add
}

split_patch() {
  local incomingpatch patches patch
  read -r -d $'\0' incomingpatch
  mapfile -d $'\0' -t patches < <(
    perl -pwe 's/^(\e\[[0-9;]*m)*(?=@@)/\0/m' <<<"$incomingpatch"
  )
  bat --color=always --plain <<<"$incomingpatch" |
    perl -pwe 's/(\e\[[0-9;]*m)*(?=@@)/\0/m' |
    fzf \
      --header-lines=1 \
      --disabled \
      --multi \
      --read0 \
      --bind="enter:execute(printf -v diff '%s' '${patches[0]}' {+}; git apply --cached <<< \$diff)+abort" \
      --preview="printf -v diff '%s' '${patches[0]}' {+}; git apply --stat <<< \$diff; bat --color=always --plain <<< \"\$diff\""
}

helptext[log]='Show commit history'
subcmd_log() {
  git log --color=always --pretty=format:$'%h\t%C(dim yellow)%ar%C(reset)\t%s' "$@" |
    fzf --prompt='log' \
      --multi \
      --track \
      --header='enter:show  ctrl-d:diff  ctrl-p:print' \
      --bind="enter:execute:git show {1} | $diffprg | less -R" \
      --bind='ctrl-d:execute:fzgit diff {1}' \
      --bind='ctrl-p:accept' \
      --preview-window=80%,bottom \
      --preview="git show {1} | $diffprg" |
    awk '{print $1}'
}

helptext[status]='Show the working tree status'
subcmd_status() {
  local preview='git diff --color=always {2..}'
  fzf --prompt='status' \
    --nth=2.. \
    --bind='start:reload:git -c color.status=always status -s' \
    --preview="$preview" \
    --bind='enter:execute:git add -p {2..}'
}

helptext[checkout]='Checkout a branch or paths to the working tree'
subcmd_checkout() { # {{{
  local branch header
  if (($# > 0)); then
    git checkout "$@"
    return
  fi
  branch=$(__current_branch)
  {
    git branch --all --color -vv
    git tag
  } |
    fzf --prompt='checkout' \
      --header="$header" \
      --bind=enter:execute:"git checkout \$(perl -pe 's/^\*?\s*(remotes\/[^\/]*\/)?([^ ]+).*/\2/' <<< {})"
}

helptext['stash-ls']='List the stash entries that you currently have'
subcmd_stash-ls() {
  if (($# > 0)); then
    git stash "$@"
    return
  fi
  local header='use ctrl-d to show a diff or ctrl-b to create a new branch'
  git stash list --pretty="%C(yellow)%h %>(14)%Cgreen%cr %C(blue)%gs" |
    fzf --prompt='stash' \
      --no-sort \
      --header="$header" \
      --bind='ctrl-d:execute: git diff {1} --color=always | less -R' \
      --bind='ctrl-b:execute(git stash branch "stash-{1}" {1})+abort' \
      --preview='git diff --color {1}'
}

watcher() {
  local files=("$(git rev-parse --show-toplevel)/.git/index")
  while IFS= read -r f; do
    [[ -e "$f" ]] && files+=("$f")
  done < <(git ls-files)
  inotifywait -q -e modify,attrib,close_write,move,create,delete "${files[@]}" &>/dev/null
}
export -f watcher

diff_histogram() {
  git diff --numstat "$@" | perl -e '
    use strict;
    use warnings;
    my $green = `tput setaf 2`;
    my $red = `tput setaf 1`;
    my $reset = `tput sgr0`;
    chomp($green, $red, $reset);
    my (@files, @adds, @dels, @totals);
    my $max = 0;

    while (<>) {
      my ($added, $deleted, $file) = split /\t/, $_, 3;
      chomp $file;

      # Skip binary files (git numstat outputs - for binary)
      next if $added eq "-" || $deleted eq "-";

      my $total = $added + $deleted;
      $max = $total if $total > $max;

      push @files, $file;
      push @adds, $added;
      push @dels, $deleted;
      push @totals, $total;
    }

    my $maxlen = 0;
    for (@files) {
      $maxlen = length($_) if length($_) > $maxlen;
    }

    my $maxdigits = length($max);
    for my $i (0 .. $#files) {
      printf " %-*s │ ", $maxlen, $files[$i];
      printf "%*d ", $maxdigits, $totals[$i];

      if ($max > 0) {
        my $graphwidth = 50;
        my $bars = int($totals[$i] * $graphwidth / $max);
        $bars = 1 if $bars == 0 && $totals[$i] > 0;

        my $plus = int($adds[$i] * $bars / $totals[$i]);
        my $minus = $bars - $plus;

        print $green;
        print "+" x $plus;
        print $red;
        print "-" x $minus;
        print $reset;
      }
      print "\n";
    }
  '
}
export -f diff_histogram

cleanup() {
  if [[ -n $listener_pid ]] && kill -0 "$listener_pid" 2>/dev/null; then
    kill "$listener_pid" 2>/dev/null
    wait "$listener_pid" 2>/dev/null
    listener_pid=''
  fi
}
trap cleanup EXIT INT TERM

has -v fzf perl git || die

mapfile -t subcmds_avail < <(compgen -A function | awk '/^subcmd_/ { sub(/^subcmd_/, "", $0); print }')

nocmd() {
  local cmd
  cmd=$(for c in "${subcmds_avail[@]}"; do
    printf "%s\t%s\n" "$c" "${helptext[$c]}"
  done)
  cmd=$(column -t -s $'\t' <<<"$cmd" | fzf | awk '{print $1}')
  if [[ -n $cmd ]]; then
    subcmd_$cmd
  else
    exit 1
  fi
}

if (($# < 1)); then
  nocmd
  exit 1
elif has "subcmd_$1"; then
  subcmd="subcmd_$1"
  shift
  "$subcmd" "$@"
elif [[ -v aliases[$1] ]]; then
  subcmd=subcmd_${aliases[$1]}
  shift
  "$subcmd" "$@"
else
  exec git "$@"
fi