#!/bin/sh
# Thomas installer:  curl -fsSL https://qizwiz.github.io/thomas-kit/install | sh
# Everything runs inside main, called on the last line, so a download cut off mid-script runs nothing.
set -eu
main() {
  BASE="${THOMAS_BASE:-https://qizwiz.github.io/thomas-kit}"
  DEST="${THOMAS_HOME:-$HOME/.local/share/thomas}"
  case "$DEST" in /*) ;; *) DEST="$PWD/$DEST" ;; esac
  while :; do case "$DEST" in *//*) DEST="${DEST%%//*}/${DEST#*//}" ;; *) break ;; esac; done
  while [ "${#DEST}" -gt 1 ] && [ "${DEST%/}" != "$DEST" ]; do DEST="${DEST%/}"; done
  for c in curl tar python3; do
    command -v "$c" >/dev/null 2>&1 || { echo "Thomas needs '$c' -- install it and run this again."; exit 1; }
  done
  python3 -c 'import sys; sys.exit(0 if sys.version_info >= (3, 10) else 1)' \
    || { echo "Thomas needs Python 3.10 or newer (python3 here is older). Nothing was installed."; exit 1; }
  # refuse every DEST shape this script could damage, BEFORE anything is downloaded or moved:
  # a symlink (moving it would replace the user's link), anything that is not a folder, an unreadable folder,
  # a folder that holds someone else's files, and a path a shebang cannot carry
  case "$DEST" in *" "*) echo "Thomas cannot be installed in a folder whose path has a space: $DEST"; exit 1 ;; esac
  if [ -L "$DEST" ] || { [ -e "$DEST" ] && [ ! -d "$DEST" ]; }; then
    echo "$DEST exists and is not a plain folder -- refusing to touch it. Set THOMAS_HOME to an empty folder."
    exit 1
  fi
  if [ -d "$DEST" ] && [ ! -r "$DEST" ]; then
    echo "$DEST exists and cannot be read -- refusing to touch it. Set THOMAS_HOME to an empty folder."
    exit 1
  fi
  if [ -d "$DEST" ] && [ -n "$(ls -A "$DEST" 2>/dev/null)" ] && [ ! -f "$DEST/.thomas-kit" ]; then
    echo "$DEST exists and is not a Thomas install -- refusing to replace it. Set THOMAS_HOME to an empty folder."
    exit 1
  fi
  # the settings guard compares RESOLVED paths: `.`, `..` and a symlinked parent resolve first
  # ($HOME/.local/../.thomas passed a plain string match). A ./.. path whose folder does not exist yet cannot be
  # resolved, so it is refused rather than guessed. DEST itself stays as given for every other check.
  case "$DEST" in */./* | */. | */../* | */..) dots=yes ;; *) dots=no ;; esac
  parent=$(dirname "$DEST")
  if [ -d "$parent" ]; then
    canon="$(cd -P "$parent" && pwd -P)/$(basename "$DEST")"
    case "$canon" in */. | */..) canon=$(cd -P "$canon" && pwd -P) ;; esac
  elif [ "$dots" = yes ]; then
    echo "$DEST contains . or .. and its folder does not exist yet -- give a plain path. Nothing was installed."
    exit 1
  else
    canon="$DEST"
  fi
  homec=$(cd -P "$HOME" 2>/dev/null && pwd -P) || homec="$HOME"
  case "$canon" in "$homec/.thomas" | "$homec/.thomas/"* | "$HOME/.thomas" | "$HOME/.thomas/"*)
    echo "$DEST is where Thomas keeps your settings -- install somewhere else. Nothing was installed."; exit 1 ;;
  esac
  # a link to a folder is fine (dotfile setups do this; -d follows it); a broken link or a non-folder is not
  if { [ -L "$HOME/.local/bin" ] && [ ! -e "$HOME/.local/bin" ]; } \
    || { [ -e "$HOME/.local/bin" ] && [ ! -d "$HOME/.local/bin" ]; }; then
    echo "$HOME/.local/bin is a broken link or not a folder -- fix it and run this again. Nothing was installed."
    exit 1
  fi
  if command -v sha256sum >/dev/null 2>&1; then sha() { sha256sum "$1" | cut -d' ' -f1; }
  else sha() { shasum -a 256 "$1" | cut -d' ' -f1; }; fi
  tmp=""
  new=""
  old=""
  placed=no
  rolled=no
  restored=no
  # put back whatever this run moved; delete only what this run created. It runs at most once (a signal arriving
  # during the failure branch's rollback must not run a second one over the restored install) and ignores further
  # signals while it works. Placement is the FLAG alone: the swap that sets it runs with signals ignored, so when
  # this can run at all the flag matches the disk (reading the disk instead deleted an unmoved install).
  rollback() {
    trap '' INT TERM HUP QUIT
    if [ "$rolled" = yes ]; then return 0; fi
    rolled=yes
    if [ "$placed" = yes ]; then rm -rf "$DEST" || true; fi
    if [ -n "$old" ] && [ -d "$old/thomas" ] && [ ! -e "$DEST" ]; then
      if mv "$old/thomas" "$DEST"; then restored=yes; fi
    fi
  }
  interrupted() {
    rollback
    echo
    if [ "$restored" = yes ]; then echo "Interrupted. Your previous install was put back."
    elif [ -n "$old" ] && [ -d "$old/thomas" ]; then echo "Interrupted. Your previous install is safe in $old/thomas."
    else echo "Interrupted. Nothing was installed (Node and the adapter live inside the Thomas folder, removed too)."; fi
    exit 130
  }
  cleanup() {
    rm -rf "$tmp"
    if [ -n "$new" ]; then rm -rf "$new"; fi
    if [ -n "$old" ] && [ ! -e "$old/thomas" ]; then rmdir "$old" 2>/dev/null || true; fi
  }
  trap cleanup EXIT
  trap interrupted INT TERM HUP QUIT
  # a signal must not land between mktemp creating a folder and the variable naming it (that would strand it)
  trap '' INT TERM HUP QUIT
  tmp=$(mktemp -d)
  trap interrupted INT TERM HUP QUIT
  echo "Downloading Thomas from $BASE ..."
  curl -fsSL "$BASE/thomas-kit.tgz" -o "$tmp/kit.tgz" \
    || { echo "Could not download the kit. Nothing was installed."; exit 1; }
  curl -fsSL "$BASE/thomas-kit.tgz.sha256" -o "$tmp/kit.sha256" \
    || { echo "Could not fetch the published checksum. Nothing was installed."; exit 1; }
  want=$(cut -d' ' -f1 "$tmp/kit.sha256")
  got=$(sha "$tmp/kit.tgz")
  if [ "$want" != "$got" ]; then
    echo "Checksum mismatch -- the download is not the published kit. Nothing was installed."
    echo "  expected $want"
    echo "  got      $got"
    exit 1
  fi
  mkdir -p "$(dirname "$DEST")"
  # unpack BESIDE the destination, so the swap below is a rename on one filesystem, never a partial copy
  trap '' INT TERM HUP QUIT
  new=$(mktemp -d "$(dirname "$DEST")/.thomas-new.XXXXXX")
  trap interrupted INT TERM HUP QUIT
  tar xzf "$tmp/kit.tgz" -C "$new"
  # the old install moves into a UNIQUE folder beside it and is deleted only after the new one sets up cleanly
  # from naming the old-install folder through the swap (two renames and a flag), no signal may land
  trap '' INT TERM HUP QUIT
  old=$(mktemp -d "$(dirname "$DEST")/.thomas-old.XXXXXX")
  if [ -d "$DEST" ]; then mv "$DEST" "$old/thomas"; fi
  if mv "$new/thomas" "$DEST"; then placed=yes; fi
  # an upgrade keeps the Node and adapter the last install fetched (copied, so a rollback still restores the old
  # install whole); install.sh skips what is already there
  if [ "$placed" = yes ] && [ -d "$old/thomas" ]; then
    for keep in node adapter; do
      if [ -d "$old/thomas/$keep" ]; then cp -Rp "$old/thomas/$keep" "$DEST/$keep" 2>/dev/null || rm -rf "${DEST:?}/$keep"; fi
    done
  fi
  trap interrupted INT TERM HUP QUIT
  if [ "$placed" = no ] || ! "$DEST/install.sh"; then
    rollback
    if [ "$restored" = yes ]; then
      echo "Setup did not finish. The new files were removed and your previous install was put back."
    elif [ -n "$old" ] && [ -d "$old/thomas" ]; then
      echo "Setup did not finish. Your previous install is safe in $old/thomas."
    else
      echo "Setup did not finish. The new files were removed; nothing was installed."
    fi
    exit 1
  fi
  # committed: the new install is set up, so finish (drop the old copy, link) without stopping halfway
  trap '' INT TERM HUP QUIT
  rm -rf "$old" || echo "Note: the previous install could not be fully removed from $old -- delete it by hand."
  if ! mkdir -p "$HOME/.local/bin"; then
    echo "Installed in $DEST, but $HOME/.local/bin could not be created: run $DEST/thomas directly."
    exit 0
  fi
  # create ~/.local/bin/thomas only if nothing is there; never replace another link or file
  link="$HOME/.local/bin/thomas"
  if [ ! -e "$link" ] && [ ! -L "$link" ]; then
    ln -s "$DEST/thomas" "$link"
  fi
  echo
  if [ -L "$link" ] && [ "$(readlink "$link")" = "$DEST/thomas" ]; then
    echo "Installed: $link -> $DEST/thomas"
    case ":$PATH:" in
      *":$HOME/.local/bin:"*) ;;
      *)
        # ADD the line, don't just print it: a first-time tester typed the full path for every question ("I paste a
        # giant line every time", a simulated first-time user, 2026-10-05) because nobody runs a printed PATH command. One line,
        # marked, added once; removing it is deleting that line.
        case "${SHELL:-}" in
          */fish | */csh | */tcsh) rc="" ;;
          */zsh) rc="${ZDOTDIR:-$HOME}/.zshrc" ;;
          */bash)
            if [ "$(uname)" = Darwin ]; then
              # macOS Terminal starts bash as a LOGIN shell, which reads only the FIRST of these that exists --
              # so append to that one; creating ~/.bash_profile beside an existing ~/.profile would silently stop
              # bash reading the user's ~/.profile
              rc="$HOME/.bash_profile"
              for f in "$HOME/.bash_profile" "$HOME/.bash_login" "$HOME/.profile"; do
                if [ -e "$f" ]; then rc="$f"; break; fi
              done
            else
              rc="$HOME/.bashrc"
            fi
            ;;
          *) rc="$HOME/.profile" ;;
        esac
        mark="# added by the Thomas installer"
        if [ -z "$rc" ]; then
          case "${SHELL:-}" in
            */fish) echo "Add it to your PATH:  fish_add_path ~/.local/bin" ;;
            *) echo "Add it to your PATH:  set path = (~/.local/bin \$path)   (in ~/.cshrc or ~/.tcshrc)" ;;
          esac
        elif [ -f "$rc" ] && grep -qF "$mark" "$rc"; then
          echo "Your PATH line is already in $rc. Open a new terminal, then just type:  thomas ask \"hello\""
        elif printf '\n%s  %s\n' 'export PATH="$HOME/.local/bin:$PATH"' "$mark" >> "$rc"; then
          echo "Added ~/.local/bin to your PATH in $rc (one line, marked \"$mark\")."
          echo "Open a new terminal, then just type:  thomas ask \"hello\""
        else
          echo "Could not write $rc. Add it to your PATH yourself:  export PATH=\"\$HOME/.local/bin:\$PATH\""
        fi
        ;;
    esac
  else
    echo "Installed in $DEST. $link already exists and is not this install's link, so it was left alone:"
    echo "  run $DEST/thomas directly."
  fi
}
main "$@"