#!/usr/bin/env sh
# dcd installer for macOS and Linux.
#
# Usage:
#   curl -fsSL https://get.devicecloud.dev/install.sh | sh
#
# Env vars:
#   DCD_VERSION       Pin a specific version (default: latest)
#   DCD_INSTALL_DIR   Override install location (default: $HOME/.dcd/bin)
#   DCD_DOWNLOAD_BASE Override the download host (default: https://get.devicecloud.dev)
#
# The whole script is wrapped in main() and only invoked on the last line, so
# a truncated download (curl | sh executes as it streams) runs nothing at all.

set -eu

err() {
  printf 'error: %s\n' "$1" >&2
  exit 1
}

info() {
  printf '%s\n' "$1"
}

# Find a dcd on PATH other than the one we just installed — usually a leftover
# `npm install -g @devicecloud.dev/dcd` that can shadow this binary. Runs in a
# subshell so the temporary IFS change never leaks back to the caller.
find_conflicting_dcd() {
  (
    IFS=:
    for dir in $PATH; do
      [ -n "$dir" ] || continue
      if [ "$dir" != "$INSTALL_DIR" ] && [ -x "$dir/dcd" ]; then
        printf '%s\n' "$dir/dcd"
        exit 0
      fi
    done
    exit 1
  )
}

# Pick the shell rc file to persist PATH into, based on the login shell.
rc_file() {
  case "${SHELL:-}" in
    *zsh)
      printf '%s\n' "${ZDOTDIR:-$HOME}/.zshrc"
      ;;
    *bash)
      if [ -f "$HOME/.bashrc" ]; then
        printf '%s\n' "$HOME/.bashrc"
      else
        printf '%s\n' "$HOME/.bash_profile"
      fi
      ;;
    *)
      printf '%s\n' "$HOME/.profile"
      ;;
  esac
}

main() {
  DOWNLOAD_BASE="${DCD_DOWNLOAD_BASE:-https://get.devicecloud.dev}"
  INSTALL_DIR="${DCD_INSTALL_DIR:-$HOME/.dcd/bin}"

  # --- detect platform ---
  os=$(uname -s)
  case "$os" in
    Darwin) os_id=darwin ;;
    Linux)  os_id=linux ;;
    *)      err "Unsupported OS: $os. Try the Windows installer (install.ps1)." ;;
  esac

  arch=$(uname -m)
  case "$arch" in
    arm64|aarch64) arch_id=arm64 ;;
    x86_64|amd64)  arch_id=x64 ;;
    *)             err "Unsupported architecture: $arch" ;;
  esac

  asset="dcd-${os_id}-${arch_id}"

  # --- resolve version ---
  if [ -n "${DCD_VERSION:-}" ]; then
    version="$DCD_VERSION"
  else
    info "Resolving latest version..."
    # /latest.json returns { "version": "5.1.0", ... }
    version=$(
      curl -fsSL "$DOWNLOAD_BASE/latest.json" \
        | sed -n 's/.*"version"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/p' \
        | head -n1
    )
    [ -z "$version" ] && err "Could not resolve latest version from $DOWNLOAD_BASE/latest.json"
  fi

  url="$DOWNLOAD_BASE/download/${version}/${asset}"
  sums_url="$DOWNLOAD_BASE/download/${version}/SHA256SUMS"

  info "Installing dcd ${version} (${os_id}-${arch_id})"
  info "  from: $url"
  info "  to:   $INSTALL_DIR/dcd"

  # --- download ---
  mkdir -p "$INSTALL_DIR"
  tmp=$(mktemp "${TMPDIR:-/tmp}/dcd-XXXXXX")
  trap 'rm -f "$tmp" "$tmp.sums"' EXIT
  curl -fSL --progress-bar "$url" -o "$tmp" \
    || err "Download failed: $url"

  # --- verify checksum ---
  curl -fsSL "$sums_url" -o "$tmp.sums" \
    || err "Could not fetch checksums: $sums_url"
  expected=$(grep -F "  ${asset}" "$tmp.sums" | awk '{print $1}' | head -n1)
  [ -z "$expected" ] && err "SHA256SUMS has no entry for $asset"

  if command -v sha256sum >/dev/null 2>&1; then
    actual=$(sha256sum "$tmp" | awk '{print $1}')
  elif command -v shasum >/dev/null 2>&1; then
    actual=$(shasum -a 256 "$tmp" | awk '{print $1}')
  else
    err "Need sha256sum or shasum to verify download"
  fi

  if [ "$expected" != "$actual" ]; then
    err "Checksum mismatch for $asset: expected $expected, got $actual"
  fi

  # --- install ---
  chmod +x "$tmp"
  mv "$tmp" "$INSTALL_DIR/dcd"
  trap - EXIT  # tmp has been moved; nothing to clean up

  # --- PATH setup ---
  path_line="export PATH=\"$INSTALL_DIR:\$PATH\""
  case ":$PATH:" in
    *":$INSTALL_DIR:"*) on_path=1 ;;
    *)                  on_path=0 ;;
  esac

  info ""
  info "✓ Installed dcd $version to $INSTALL_DIR/dcd"

  if [ "$on_path" -eq 0 ]; then
    rc=$(rc_file)
    if [ -f "$rc" ] && grep -Fq "$INSTALL_DIR" "$rc" 2>/dev/null; then
      # rc already references the dir (e.g. a re-install); don't duplicate it.
      info ""
      info "  $INSTALL_DIR is already configured in $rc."
      info "  Restart your shell, or run:  $path_line"
    elif printf '\n# dcd\n%s\n' "$path_line" >> "$rc" 2>/dev/null; then
      info ""
      info "  Added $INSTALL_DIR to your PATH in $rc."
      info "  Restart your shell, or run:  $path_line"
    else
      info ""
      info "  $INSTALL_DIR is not on your PATH. Add this to your shell rc:"
      info "    $path_line"
    fi
  fi

  # --- warn about a conflicting (shadowing) install ---
  if conflict=$(find_conflicting_dcd); then
    info ""
    info "! Another dcd is already on your PATH:"
    info "    $conflict"
    info "  This is usually a previous 'npm install -g @devicecloud.dev/dcd', which"
    info "  can shadow this binary depending on PATH order. Remove it with:"
    info "    npm uninstall -g @devicecloud.dev/dcd"
  fi

  if [ "$on_path" -eq 1 ]; then
    info ""
    info "  Try: dcd --help"
  fi
}

main "$@"