#!/usr/bin/env bash
# TRVChek installer -- macOS. No sudo required.
set -euo pipefail

VERSION="3.0.0"
EXPECTED_SHA="4da431226efc1419c9fa61db2aac19f041c4a98611ef9defe445c92b610906c7"
BASE_URL="https://install.trvchek.com"
TARBALL_URL="$BASE_URL/releases/trvchek-$VERSION.tar.gz"

TRV_HOME="$HOME/.trvchek"
VERSIONS_DIR="$TRV_HOME/versions"
TARGET_DIR="$VERSIONS_DIR/$VERSION"
CURRENT_LINK="$TRV_HOME/current"
BIN_DIR="$HOME/.local/bin"
PATH_MARKER="# added by TRVChek installer"

say()  { printf '%s\n' "$*"; }
fail() { printf 'TRVChek install failed: %s\n' "$*" >&2; exit 1; }

TMP_DIR=""
cleanup() { [ -n "$TMP_DIR" ] && rm -rf "$TMP_DIR" || true; }
trap cleanup EXIT INT TERM

say "TRVChek installer (v$VERSION)"

# 1. OS check ---------------------------------------------------------------
[ "$(uname -s)" = "Darwin" ] || fail "this installer supports macOS only (found $(uname -s))."

# 2. Python check -----------------------------------------------------------
PY=""
for candidate in python3 /usr/bin/python3 /opt/homebrew/bin/python3 /usr/local/bin/python3; do
  if command -v "$candidate" >/dev/null 2>&1; then
    if "$candidate" -c 'import sys; sys.exit(0 if sys.version_info >= (3, 9) else 1)' >/dev/null 2>&1; then
      PY="$(command -v "$candidate")"
      break
    fi
  fi
done
[ -n "$PY" ] || fail "Python 3.9 or newer is required. Install it, then re-run this installer."
say "Using Python: $PY ($("$PY" -c 'import platform;print(platform.python_version())'))"

command -v curl >/dev/null 2>&1 || fail "curl is required."
command -v shasum >/dev/null 2>&1 || fail "shasum is required."
command -v tar >/dev/null 2>&1 || fail "tar is required."

# 3. Download -------------------------------------------------------------
TMP_DIR="$(mktemp -d "${TMPDIR:-/tmp}/trvchek-install.XXXXXX")"
ARCHIVE="$TMP_DIR/trvchek-$VERSION.tar.gz"
say "Downloading $TARBALL_URL"
curl -fsSL "$TARBALL_URL" -o "$ARCHIVE" || fail "could not download the release archive."

# 4. Verify checksum ------------------------------------------------------
ACTUAL_SHA="$(shasum -a 256 "$ARCHIVE" | awk '{print $1}')"
if [ "$ACTUAL_SHA" != "$EXPECTED_SHA" ]; then
  fail "checksum mismatch. Expected $EXPECTED_SHA, got $ACTUAL_SHA. Nothing was installed."
fi
say "Checksum verified."

# 5. Unpack into temp -----------------------------------------------------
UNPACK="$TMP_DIR/unpack"
mkdir -p "$UNPACK"
tar -xzf "$ARCHIVE" -C "$UNPACK" || fail "could not unpack the release archive."
PAYLOAD="$UNPACK/trvchek-$VERSION"
[ -f "$PAYLOAD/trvchek-cli" ] || fail "release archive is incomplete (trvchek-cli missing)."
[ -f "$PAYLOAD/trvchek/core/structural.py" ] || fail "release archive is incomplete (core missing)."

# 6. Atomic install -------------------------------------------------------
# User state ($TRV_HOME/license.json etc.) is never touched.
mkdir -p "$VERSIONS_DIR"
STAGING="$VERSIONS_DIR/.staging-$VERSION.$$"
rm -rf "$STAGING"
cp -R "$PAYLOAD" "$STAGING"
chmod 0755 "$STAGING/trvchek-cli"

if [ -e "$TARGET_DIR" ]; then
  PREVIOUS="$VERSIONS_DIR/.previous-$VERSION.$$"
  mv "$TARGET_DIR" "$PREVIOUS"
  if mv "$STAGING" "$TARGET_DIR"; then
    rm -rf "$PREVIOUS"
  else
    mv "$PREVIOUS" "$TARGET_DIR"
    fail "could not replace the existing install; previous version left intact."
  fi
else
  mv "$STAGING" "$TARGET_DIR"
fi

# Atomic symlink flip: create alongside, then rename over.
TMP_LINK="$TRV_HOME/.current.$$"
ln -sfn "$TARGET_DIR" "$TMP_LINK"
mv -f "$TMP_LINK" "$CURRENT_LINK"
say "Installed to $TARGET_DIR"

# 7. Launchers ------------------------------------------------------------
mkdir -p "$BIN_DIR"
cat > "$BIN_DIR/trvchek" <<LAUNCHER
#!/usr/bin/env bash
# TRVChek launcher (generated by installer)
set -euo pipefail
TRV_ROOT="\$HOME/.trvchek/current"
PY="${PY}"
[ -x "\$PY" ] || PY="\$(command -v python3)"
export PYTHONPATH="\$TRV_ROOT\${PYTHONPATH:+:\$PYTHONPATH}"
exec "\$PY" "\$TRV_ROOT/trvchek-cli" "\$@"
LAUNCHER
chmod 0755 "$BIN_DIR/trvchek"

cat > "$BIN_DIR/trvw" <<WATCHER
#!/usr/bin/env bash
# TRVChek Watcher launcher (generated by installer)
set -euo pipefail
exec "\$HOME/.local/bin/trvchek" watch "\$@"
WATCHER
chmod 0755 "$BIN_DIR/trvw"
say "Launchers installed: $BIN_DIR/trvchek, $BIN_DIR/trvw"

# 8. PATH setup (idempotent, non-fatal) -----------------------------------
PATH_LINE="export PATH=\"\$HOME/.local/bin:\$PATH\" $PATH_MARKER"
case ":$PATH:" in
  *":$BIN_DIR:"*) PATH_OK=1 ;;
  *) PATH_OK=0 ;;
esac

PROFILE=""
case "${SHELL:-}" in
  *zsh) PROFILE="$HOME/.zshrc" ;;
  *bash) PROFILE="$HOME/.bash_profile" ;;
  *) PROFILE="$HOME/.profile" ;;
esac

if [ -n "$PROFILE" ] && [ -f "$PROFILE" ] && grep -Fq "$PATH_MARKER" "$PROFILE" 2>/dev/null; then
  say "PATH entry already present in $PROFILE"
elif [ -n "$PROFILE" ] && printf '%s\n' "$PATH_LINE" >> "$PROFILE" 2>/dev/null; then
  say "Added $BIN_DIR to PATH in $PROFILE"
  say "Open a new terminal, or run: source $PROFILE"
else
  say ""
  say "NOTE: could not update your shell profile automatically."
  say "Add this line to your shell profile yourself:"
  say "  $PATH_LINE"
fi

# 9. Self-test ------------------------------------------------------------
if "$BIN_DIR/trvchek" --help >/dev/null 2>&1; then
  say "Self-test passed."
else
  if "$PY" -c "import sys; sys.path.insert(0, '$TARGET_DIR'); import trvchek.core.structural" >/dev/null 2>&1; then
    say "Self-test passed (engine imports cleanly)."
  else
    fail "self-test failed. The engine did not load. Nothing else was changed."
  fi
fi

say ""
say "TRVChek $VERSION installed."
say "Next:"
say "  trvchek activate YOUR-LICENSE-KEY"
say "  cd your-project && trvw --auto-fix"
if [ "$PATH_OK" = "0" ]; then
  say ""
  say "(If 'trvchek' is not found yet, start a new terminal session first.)"
fi