#!/usr/bin/env bash
# Browse git log through fzf, it will search both commit messages and code.
# Anything you can pass to git log you can pass to this script. It also
# supports passing in --side to configure delta to use side-by-side mode.
#
# While looking at the git log you can press CTRL+o to open it in a browser.
#
# Examples:
#   gl         # Search commit messages
#   gl -S      # Search commit messages and code using git's -S flag
#   gl -G      # Search commit messages and code using git's -G flag
#   gl --side  # Show diffs side by side
#   gl [any flag that git log supports]

set -o errexit
set -o pipefail
set -o nounset

# Later on we'll use this to open / browse the selected commit.
open_commit_url() {
  local commit="${1}"

  [ -z "${commit}" ] && return

  local branch=
  local remote=
  local remote_url=
  local normalized_url=

  branch="$(git branch --show-current)"
  remote="$(git config --get "branch.${branch}.remote")"
  remote_url="$(git remote get-url "${remote:-origin}" 2>/dev/null)"

  # Ensure all remote formats (SSH, HTTPS, variants, etc.) get converted into
  # an https:// URL without .git since this is what will get opened.
  normalized_url="$(sed -E 's|^(git@\|https?://\|ssh://git@)([:/]+)?||; s|\.git/?$||; s|:|/|; s|^|https://|; s|/+|/|g; s|https:/|https://|; s|/$||' <<<"${remote_url}")"

  local commit_path=

  case "${normalized_url}" in
  *gitlab*) commit_path="-/commit/${commit}" ;;
  *bitbucket*) commit_path="commits/${commit}" ;;
  *) commit_path="commit/${commit}" ;;
  esac

  local commit_url="${normalized_url}/${commit_path}"

  if [[ "${OSTYPE}" == linux* ]]; then
    xdg-open "${commit_url}" >/dev/null 2>&1
  else
    open "${commit_url}" >/dev/null 2>&1
  fi
}
export -f open_commit_url

if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
  GIT_ARGS=("--color=always" "--date=short")
  GIT_LOG_SEARCH_MODE="--grep"

  for arg in "${@}"; do
    if [ "${arg}" = "--side" ]; then
      # Handle displaying side by side.
      export DELTA_FEATURES="${DELTA_FEATURES:-} side-by-side"
    elif [ "${arg}" = "-S" ]; then
      GIT_LOG_SEARCH_MODE="-S"
    elif [ "${arg}" = "-G" ]; then
      GIT_LOG_SEARCH_MODE="-G"
    else
      GIT_ARGS+=("${arg}")
    fi
  done

  printf -v GIT_ARGS_STR "%q " "${GIT_ARGS[@]}"

  # %at is a hidden timestamp, it it used for sorting later.
  # COLOR is a placeholder that changes depending on the search result type.
  FORMAT="%at %C(magenta)%h %C(green)%ad %C(COLOR)> %C(reset)%s"
  FORMAT_MESSAGE="${FORMAT//COLOR/blue}"
  FORMAT_CODE="${FORMAT//COLOR/yellow}"

  STRIP_TIMESTAMP="cut -d ' ' -f 2-"

  GIT_LOG_DEFAULT="git log --pretty='${FORMAT_MESSAGE}' ${GIT_ARGS_STR:-} | ${STRIP_TIMESTAMP}"

  # There's a lot going on here, here's a few comments for my future self:
  #
  # start:reload
  #   Run this when fzf starts, this works instead of piping in git log because
  #   we also use --disabled.
  #
  # change:reload:sleep
  #   change  fires every time a key is pressed
  #   reload  starts a new process with the typed query
  #   sleep   acts as a 150ms debounce to trigger the change / reload
  #
  # [[ \"\$query\" =~ [A-Z] ]] && flag=\"\" || flag=\"--regexp-ignore-case\"
  #   This is effectively smart casing, if any capital letters exist then the
  #   search is case sensitive, otherwise it's case insensitive.
  #
  # --grep and -G run as separate searches to make them an OR instead of AND,
  # we run them in a subshell to sort their results later. We always want newest
  # commits on top, sorted by the hidden timestamp and we use a different > color
  # to know if it's a message (blue) or code (yellow) result.
  #
  # The CTRL+o bind is running through bash explicitly because when fzf triggers
  # execute, it will use your system's shell and exporting a function like we're
  # doing doesn't work in zsh, so we're forcing bash.
  #
  # If you're sniping this script without DotFriedRice, you'll likely want to
  # set a number of FZF_DEFAULT_OPTS such as the ones you can find here:
  #   https://github.com/nickjj/dotfriedrice/blob/master/.config/fzf/config.sh
  fzf \
    --ansi --border=top --border-label " [ Enter: Show (local) | CTRL-o: Open (browser) | CTRL-y: Copy (commit) ] " \
    --disabled --no-sort --query "" \
    --bind "start:reload(${GIT_LOG_DEFAULT})" \
    --bind "change:reload:sleep 0.15
        query={q}
        if [ -z \"\${query}\" ]; then
          ${GIT_LOG_DEFAULT}
        else
          [[ \"\${query}\" =~ [A-Z] ]] && case= || case=\"--regexp-ignore-case\"
          {
            if [ \"${GIT_LOG_SEARCH_MODE}\" = \"--grep\" ]; then
              git log \${case} --pretty='${FORMAT_MESSAGE}' ${GIT_ARGS_STR:-} ${GIT_LOG_SEARCH_MODE} \"\${query}\"
            else
              (
                git log \${case} --pretty='${FORMAT_MESSAGE}' ${GIT_ARGS_STR:-} --grep \"\${query}\"
                git log \${case} --pretty='${FORMAT_CODE}' ${GIT_ARGS_STR:-} ${GIT_LOG_SEARCH_MODE} \"\${query}\"
              ) | sort --numeric-sort --reverse --unique --key 1,1
            fi
          } | ${STRIP_TIMESTAMP}
        fi" \
    --bind "enter:execute(git show {1} -- | delta --paging always)" \
    --bind "ctrl-o:execute-silent(bash -c 'source ${0}; open_commit_url {1}')" \
    --bind "ctrl-y:execute-silent(git show {1} -- | clip-copy)" \
    --preview "git show {1} -- | delta --width=\${FZF_PREVIEW_COLUMNS}" \
    --preview-window="right:70%" || true
fi