#!/usr/bin/env bash
#
# git-commitiq — semantic commit summaries as a real git subcommand.
#
# Works via git's native plugin resolution: any executable named
# `git-<word>` found on $PATH becomes callable as `git <word>`. No fork
# of git, no core changes, no special registration required.
#
# Flow: `git commitiq -m "..."` runs the real `git commit` first, then
# asks the configured LLM for a structured JSON summary of the diff and
# stores it as a git note on the commit (refs/notes/commits). The first
# commit in a repo silently runs `notes-enable` so git push/fetch also
# sync the notes refs - no manual setup step needed.

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
LIB_DIR="$(cd "$SCRIPT_DIR/../lib" && pwd)"

usage() {
  cat <<'EOF'
git commitiq — semantic commit summaries

Usage:
  git commitiq [git commit args...]      Same as `git commitiq commit ...`
  git commitiq commit [git commit args]  Run a real git commit, then attach an LLM summary as a git note
  git commitiq setup                     Interactive setup wizard (provider/model/API key)
  git commitiq setup --provider <p> --api-key <key> [--model <m>]
                                          Non-interactive setup
  git commitiq config get <key>          Show a config value (provider|model|api_key)
  git commitiq config set <key> <val>    Change a config value anytime
  git commitiq config unset <key>        Remove a config value
  git commitiq config list               Show current config (API key masked)
  git commitiq notes-enable [remote]     Configure this repo so 'git push'/'git fetch' also sync git notes
  git commitiq notes-enable --quiet       Same, but silent (used automatically on your first commit in a repo)
  git commitiq push [git push args]      Push like 'git push', also syncing git notes (refs/notes/*)
  git commitiq show <sha>                Print the stored JSON summary from git notes (sha or prefix)
  git commitiq log                       List commits that have a stored summary
  git commitiq help                      Show this message

Examples:
  git commitiq -m "fix login bug"
  git commitiq commit -am "refactor auth module"
  git commitiq setup --provider anthropic --api-key sk-ant-... --model claude-3-5-sonnet-latest
  git commitiq config set provider openai
  git commitiq notes-enable
  git commitiq push origin main
  git commitiq show a1b2c3
EOF
}

ensure_git_repo() {
  if ! git rev-parse --is-inside-work-tree >/dev/null 2>&1; then
    echo "fatal: not a git repository (or any of the parent directories): .git" >&2
    echo "commitiq: an initialized git repository is required to run this command." >&2
    exit 128
  fi
}

do_commit() {
  ensure_git_repo

  # Run the real commit first. If it fails (nothing staged, conflict,
  # rejected by a pre-commit hook, etc.), we stop here via `set -e` -
  # no LLM call, no note, identical behavior to plain `git commit`.
  git commit "$@"

  # First commitiq commit in this repo: silently configure notes
  # push/fetch sync (same as `git commitiq notes-enable`) so notes
  # travel with 'git push'/'git fetch'. Idempotent and non-fatal - a
  # repo without a remote is skipped, and nothing breaks if it fails.
  do_notes_enable --quiet || true

  SHA="$(git rev-parse HEAD)"
  REPO_ROOT="$(git rev-parse --show-toplevel)"
  OUT_DIR="$REPO_ROOT/.commitiq"
  mkdir -p "$OUT_DIR"

  if git rev-parse -q --verify HEAD^ >/dev/null; then
    FULL_DIFF="$(git diff HEAD^ HEAD)"
  else
    FULL_DIFF="$(git show --format='' HEAD)"
  fi

  # Truncate diffs larger than 50KB (~1500 lines) to prevent exceeding LLM context limits
  local max_diff_bytes=50000
  if [ "${#FULL_DIFF}" -gt "$max_diff_bytes" ]; then
    FULL_DIFF="$(printf '%s' "$FULL_DIFF" | head -c "$max_diff_bytes")"$'\n\n[... diff truncated due to 50KB size limit ...]'
  fi

  SUMMARY=""
  if [ -f "$LIB_DIR/commitiq_llm.sh" ]; then
    SUMMARY="$(printf '%s' "$FULL_DIFF" | bash "$LIB_DIR/commitiq_llm.sh" 2>>"$OUT_DIR/.commitiq.log" || true)"
  fi

  if [ -n "$SUMMARY" ]; then
    if printf '%s\n' "$SUMMARY" | git notes add -f -F - 2>>"$OUT_DIR/.commitiq.log"; then
      echo "[commitiq] JSON summary attached to $SHA via git notes"
    else
      echo "[commitiq] warning: commit succeeded but the note could not be attached to $SHA (see $OUT_DIR/.commitiq.log)" >&2
    fi
  else
    if printf '%s\n' "commitiq: no semantic summary available (no provider configured, or the LLM request failed). See $OUT_DIR/.commitiq.log. Run 'git commitiq setup'." \
        | git notes add -f -F - 2>>"$OUT_DIR/.commitiq.log"; then
      echo "[commitiq] no summary generated - placeholder note attached to $SHA"
    else
      echo "[commitiq] warning: could not attach placeholder note to $SHA (see $OUT_DIR/.commitiq.log)" >&2
    fi
  fi
}

do_show() {
  ensure_git_repo
  local query="${1:-}"
  if [ -z "$query" ]; then
    echo "usage: git commitiq show <sha-or-prefix>" >&2
    exit 1
  fi

  local full_sha
  if ! full_sha="$(git rev-parse --verify "$query^{commit}" 2>/dev/null)"; then
    echo "No commit matching '$query'" >&2
    exit 1
  fi

  if ! git notes show "$full_sha" 2>/dev/null; then
    echo "No commitiq note found for $full_sha" >&2
    exit 1
  fi
}

do_log() {
  ensure_git_repo
  local found=0
  local _note_sha annotated_sha
  while read -r _note_sha annotated_sha; do
    git log -1 --format="%h  %ad  %s" --date=short "$annotated_sha"
    found=1
  done < <(git notes list 2>/dev/null)
  if [ "$found" -eq 0 ]; then
    echo "No stored summaries yet."
  fi
}

is_remote_or_url() {
  local arg="$1"
  if git remote | grep -Fqx "$arg"; then
    return 0
  fi
  case "$arg" in
    *://*|*@*:*|*.git) return 0 ;;
  esac
  return 1
}

do_push() {
  ensure_git_repo

  # No args: behave exactly like a bare `git push` - the refspecs
  # configured by `notes-enable` already push branches + notes.
  if [ $# -eq 0 ]; then
    git push
    return $?
  fi

  # Modes where appending a notes refspec would be wrong or destructive:
  # --delete/-d would DELETE the remote notes ref too; --mirror already
  # mirrors every ref under refs/, notes included; --all can't be
  # combined with refspecs at all (git refuses); -u/--set-upstream
  # sets up tracking for named branches; an explicit :refs/notes/...
  # delete must be forwarded untouched (not re-pushed).
  local a
  local plain=0
  for a in "$@"; do
    case "$a" in
      --delete|-d|--mirror|--all|-u|--set-upstream) plain=1 ;;
      :*refs/notes/*) plain=1 ;;
    esac
  done
  if [ "$plain" -eq 1 ]; then
    git push "$@"
    return $?
  fi

  # Count non-flag args, skipping the value of -o/--push-option (which
  # would otherwise be miscounted as a refspec). A lone remote/URL means
  # "push per configured refspecs" (which already include notes) -
  # appending would override them and push notes ONLY. An explicit
  # refspec on the command line means "push exactly this", so the notes
  # refspec must be appended.
  local skip_next=0 non_flags=0 last_non_flag=""
  for a in "$@"; do
    if [ "$skip_next" -eq 1 ]; then
      skip_next=0
      continue
    fi
    case "$a" in
      -o|--push-option) skip_next=1 ;;
      -*) ;;
      *)
        non_flags=$((non_flags + 1))
        last_non_flag="$a"
        ;;
    esac
  done

  local append_notes=0
  if [ "$non_flags" -gt 1 ]; then
    append_notes=1
  elif [ "$non_flags" -eq 1 ] && ! is_remote_or_url "$last_non_flag"; then
    append_notes=1
  fi

  # Only append if the local notes ref exists - pushing a refspec whose
  # src doesn't exist makes git abort the whole push.
  if [ "$append_notes" -eq 1 ] && git rev-parse -q --verify refs/notes/commits >/dev/null 2>&1; then
    git push "$@" "refs/notes/*:refs/notes/*"
  else
    git push "$@"
  fi
}

do_notes_enable() {
  ensure_git_repo

  # --quiet: no output at all unless something was actually configured
  # (then exactly one line). Used by `do_commit` on a repo's first
  # commitiq commit, so setup is invisible but still discoverable.
  local quiet=0
  local remote=""
  while [[ $# -gt 0 ]]; do
    case "$1" in
      --quiet|-q)
        quiet=1
        shift
        ;;
      --remote)
        remote="$2"
        shift 2
        ;;
      -h|--help)
        echo "usage: git commitiq notes-enable [remote-name | --remote <name>] [--quiet]" >&2
        exit 0
        ;;
      *)
        remote="$1"
        shift
        ;;
    esac
  done

  if [ -z "$remote" ]; then
    remote="$(git remote | head -n 1)"
  fi
  if [ -z "$remote" ]; then
    if [ "$quiet" -eq 1 ]; then
      return 0
    fi
    echo "commitiq: no git remote configured. Add one (e.g. 'git remote add origin <url>') and re-run." >&2
    exit 1
  fi
  if [ -z "$(git config --get "remote.$remote.url")" ]; then
    if [ "$quiet" -eq 1 ]; then
      return 0
    fi
    echo "commitiq: remote '$remote' not found." >&2
    exit 1
  fi

  local changed=0
  local say
  say() {
    [ "$quiet" -eq 1 ] || printf '%s\n' "$@"
  }

  # Fetch: pull remote notes down (keeps any existing fetch refspecs).
  if ! git config --get-all "remote.$remote.fetch" | grep -Fqx "+refs/notes/*:refs/notes/*" \
     && ! git config --get-all "remote.$remote.fetch" | grep -Fqx "refs/notes/*:refs/notes/*"; then
    git config --add "remote.$remote.fetch" "+refs/notes/*:refs/notes/*"
    say "[commitiq] added fetch refspec: +refs/notes/*:refs/notes/*"
    changed=1
  fi

  # Push: git notes are NOT pushed by default, and defining a push
  # refspec disables git's implicit branch pushing - so we always add
  # the branch refspec alongside the notes refspec.
  local existing_push
  existing_push="$(git config --get-all "remote.$remote.push" || true)"
  if [ -z "$existing_push" ]; then
    git config --add "remote.$remote.push" "refs/heads/*:refs/heads/*"
    say "[commitiq] added push refspec: refs/heads/*:refs/heads/*"
    git config --add "remote.$remote.push" "refs/notes/*:refs/notes/*"
    say "[commitiq] added push refspec: refs/notes/*:refs/notes/*"
    changed=1
  elif ! printf '%s\n' "$existing_push" | grep -Fqx "refs/notes/*:refs/notes/*"; then
    git config --add "remote.$remote.push" "refs/notes/*:refs/notes/*"
    say "[commitiq] added push refspec: refs/notes/*:refs/notes/*"
    say "[commitiq] NOTE: this remote already had custom push refspecs - make sure one of them covers refs/heads/*"
    say "[commitiq]       or plain 'git push' will not push branches. See: git config --get-all remote.$remote.push"
    changed=1
  else
    say "[commitiq] notes push refspec already configured."
  fi

  # Show notes in `git log` by default, and carry notes across rebase.
  if ! git config --get-all notes.displayRef | grep -Fqx "refs/notes/commits"; then
    git config --add notes.displayRef "refs/notes/commits"
    say "[commitiq] notes.displayRef = refs/notes/commits (git log will show notes)"
    changed=1
  fi
  local existing_rewrite
  existing_rewrite="$(git config --get notes.rewriteRef || true)"
  if [ -n "$existing_rewrite" ] && [ "$existing_rewrite" != "refs/notes/commits" ]; then
    say "[commitiq] NOTE: notes.rewriteRef already set to '$existing_rewrite' - leaving it untouched."
  elif [ "$existing_rewrite" != "refs/notes/commits" ]; then
    git config notes.rewriteRef "refs/notes/commits" 2>/dev/null || true
    say "[commitiq] notes.rewriteRef = refs/notes/commits (notes survive rebase)"
    changed=1
  fi

  if [ "$quiet" -eq 1 ]; then
    if [ "$changed" -eq 1 ]; then
      echo "[commitiq] notes sync enabled for this repo ('git push'/'git fetch' will include notes)"
    fi
    return 0
  fi

  echo ""
  echo "[commitiq] done. 'git push' now sends branches + notes; 'git fetch'/'git pull' brings notes back."
  echo "[commitiq] tip: use bare 'git push' - an explicit push like 'git push origin main' skips notes."
  echo "[commitiq] caveat: GitHub/GitLab store notes but do not render them in their web UI."
  echo "[commitiq]         view them with: git log --show-notes / git commitiq show <sha>"
}

case "${1:-}" in
  setup)
    shift
    bash "$LIB_DIR/commitiq_config.sh" setup "$@"
    ;;
  config)
    shift
    bash "$LIB_DIR/commitiq_config.sh" "$@"
    ;;
  notes-enable|enable-notes|notes)
    shift
    do_notes_enable "$@"
    ;;
  push)
    shift
    do_push "$@"
    ;;
  show)
    shift
    do_show "$@"
    ;;
  log)
    do_log
    ;;
  help|--help|-h)
    usage
    ;;
  commit)
    shift
    do_commit "$@"
    ;;
  *)
    # No recognized commitiq keyword as the first arg - treat everything
    # (including things like `-m "msg"`) as `git commit` arguments.
    do_commit "$@"
    ;;
esac