#!/bin/sh
# Shahi installer.
#
#   curl -fsSL https://getshahi.dev/install | sh
#
# 1. Installs herdr 0.9.5 into ~/.local/bin if herdr is missing,
#    and only after its SHA-256 matches the one written below.
# 2. Installs the Shahi plugin into herdr (herdr plugin install iYassr/shahi).
# 3. Starts herdr in the background if it is not running, which sets up
#    Shahi's service.
# 4. Shows a QR code to scan with the Shahi app.
#
# Running it again skips what is already done and shows a new code. The plugin
# manages its service and herdr's agent integrations. If bun is missing, its
# installer adds ~/.bun/bin to your shell profile. No administrator password
# is requested.
# Source: https://github.com/iYassr/shahi/blob/master/site/install.sh
set -eu

HERDR_VERSION="0.9.5"
HERDR_SHA256_MACOS_AARCH64="fb77c2232a05a8035421382c894392f4174e4e38a18e48af3dd0290157c3a7e2"
HERDR_SHA256_MACOS_X86_64="5fb0a908ec7f6745e3e245738b06bfad56c46391c391ab3c0955fbead01f1369"
HERDR_SHA256_LINUX_AARCH64="17d7536f2da50859523680ef279dffcac8e4a235f4e46fe8da6c2ec44141897c"
HERDR_SHA256_LINUX_X86_64="14d9e8bc8b4a9e0118d77c32266f76d461f09b40342eb23752960bd89f59929d"
HERDR_MIN="0.9.0"
BIN_DIR="$HOME/.local/bin"

say() { printf '%s\n' "$*"; }
step() { printf '\n\033[1m%s\033[0m\n' "$*"; }
fail() { printf '\nShahi was not installed: %s\n' "$*" >&2; exit 1; }

# True when version $1 is at least $2 (major.minor.patch).
at_least() {
  awk -v a="$1" -v b="$2" 'BEGIN {
    split(a, x, "."); split(b, y, ".")
    for (i = 1; i <= 3; i++) { if (x[i] + 0 > y[i] + 0) exit 0; if (x[i] + 0 < y[i] + 0) exit 1 }
    exit 0
  }'
}

sha256() {
  if command -v shasum >/dev/null 2>&1; then shasum -a 256 "$1" | cut -d' ' -f1
  elif command -v sha256sum >/dev/null 2>&1; then sha256sum "$1" | cut -d' ' -f1
  else fail "neither shasum nor sha256sum is installed, so herdr's download cannot be checked."
  fi
}

platform() {
  case "$(uname -s)" in
    Darwin) os=macos ;;
    Linux) os=linux ;;
    *) fail "Shahi runs on macOS and Linux, and this is $(uname -s)." ;;
  esac
  case "$(uname -m)" in
    arm64 | aarch64) cpu=aarch64 ;;
    x86_64 | amd64) cpu=x86_64 ;;
    *) fail "herdr has no build for this processor ($(uname -m))." ;;
  esac
  case "$os-$cpu" in
    macos-aarch64) expected=$HERDR_SHA256_MACOS_AARCH64 ;;
    macos-x86_64) expected=$HERDR_SHA256_MACOS_X86_64 ;;
    linux-aarch64) expected=$HERDR_SHA256_LINUX_AARCH64 ;;
    linux-x86_64) expected=$HERDR_SHA256_LINUX_X86_64 ;;
  esac
}

# Sets HERDR to a herdr this script can use, installing one if there is none.
find_herdr() {
  HERDR=""
  if command -v herdr >/dev/null 2>&1; then HERDR=$(command -v herdr)
  elif [ -x "$BIN_DIR/herdr" ]; then HERDR="$BIN_DIR/herdr"
  fi
  if [ -n "$HERDR" ]; then
    have=$("$HERDR" --version 2>/dev/null | awk '{print $NF}')
    printf '%s\n' "$have" | grep -Eq '^[0-9]+\.[0-9]+\.[0-9]+$' ||
      fail "could not read a supported version from $HERDR --version. Check that herdr runs, then try again."
    if at_least "${have:-0}" "$HERDR_MIN"; then
      say "herdr $have is installed."
      return
    fi
    fail "herdr $have is older than Shahi supports ($HERDR_MIN or newer). Update it with:  $HERDR update   then run this again."
  fi
  command -v curl >/dev/null 2>&1 || fail "curl is needed to download herdr. Install curl, then run this again."
  install_herdr
}

install_herdr() {
  step "Installing herdr $HERDR_VERSION"
  url="https://github.com/herdrdev/herdr/releases/download/v$HERDR_VERSION/herdr-$os-$cpu"
  tmp=$(mktemp -d)
  trap 'rm -rf "$tmp"' EXIT
  curl -fsSL --retry 3 -o "$tmp/herdr" "$url" || fail "could not download herdr from $url"
  got=$(sha256 "$tmp/herdr")
  # Never run a binary whose bytes are not the ones Shahi pinned.
  [ "$got" = "$expected" ] || fail "herdr's download does not match its expected SHA-256 (expected $expected, got $got). Nothing was installed."
  mkdir -p "$BIN_DIR"
  chmod 755 "$tmp/herdr"
  mv "$tmp/herdr" "$BIN_DIR/herdr"
  HERDR="$BIN_DIR/herdr"
  say "Installed herdr $HERDR_VERSION in $BIN_DIR, checked against its SHA-256."
  case ":$PATH:" in
    *":$BIN_DIR:"*) ;;
    *) PATH_HINT=1 ;;
  esac
}

# What the steps below need and cannot install without a password: git, which
# herdr fetches plugins with, and curl, unzip and bash when bun's installer
# will be needed. Checked before anything is changed, and
# named together, so one command fixes them all.
need_tools() {
  missing=""
  # `git --version`, not `command -v git`: a Mac without the command-line
  # tools has a /usr/bin/git that only offers to install them.
  git --version >/dev/null 2>&1 || missing="git"
  if ! command -v bun >/dev/null 2>&1 && [ ! -x "$HOME/.bun/bin/bun" ]; then
    for tool in curl unzip bash; do
      command -v "$tool" >/dev/null 2>&1 || missing="${missing:+$missing }$tool"
    done
  fi
  [ -z "$missing" ] && return
  if [ "$os" = macos ]; then
    fail "this computer needs $missing first. Install missing command-line tools (for git: xcode-select --install), then run this again."
  fi
  # A cloud image's package lists can be empty, so apt is told to fetch them.
  if command -v apt-get >/dev/null 2>&1; then hint="sudo apt-get update && sudo apt-get install -y $missing"
  elif command -v dnf >/dev/null 2>&1; then hint="sudo dnf install -y $missing"
  elif command -v pacman >/dev/null 2>&1; then hint="sudo pacman -S --needed $missing"
  elif command -v apk >/dev/null 2>&1; then hint="sudo apk add $missing"
  else hint="install: $missing"
  fi
  names=$(printf %s "$missing" | awk '{ for (i = 1; i <= NF; i++) printf "%s%s", $i, (i == NF ? "" : i == NF - 1 ? " and " : ", ") }')
  fail "this computer needs $names first. Run:  $hint   then run this again."
}

server_running() { "$HERDR" status server 2>/dev/null | grep -q '^status: running'; }

plugin_installed() {
  "$HERDR" plugin list --json 2>/dev/null | grep -q '"plugin_id": *"shahi"'
}

install_plugin() {
  if plugin_installed; then
    say "The Shahi plugin is installed."
    return
  fi
  step "Installing the Shahi plugin"
  # -y: the confirmation herdr asks for would read this script, not a person.
  "$HERDR" plugin install -y iYassr/shahi || fail "herdr could not install the Shahi plugin; its output above says why."
}

start_herdr() {
  if server_running; then
    STARTED=0
    return
  fi
  step "Starting herdr in the background"
  # The plugin's startup hook sets Shahi up when herdr starts. Run herdr to
  # open it; it attaches to this same session. In a session of its own where
  # setsid exists: herdr handles SIGHUP itself, so under `ssh -t host '…|sh'`
  # nohup did not save it, and it shut down half a second after starting
  # when the terminal closed (fresh-VM run before the public launch).
  STARTED_AT=$(date +%s)
  if command -v setsid >/dev/null 2>&1; then
    setsid nohup "$HERDR" server </dev/null >/dev/null 2>&1 &
  else
    nohup "$HERDR" server </dev/null >/dev/null 2>&1 &
  fi
  deadline=$((STARTED_AT + 30))
  until server_running; do
    [ "$(date +%s)" -lt "$deadline" ] || fail "herdr did not start within 30 seconds. Try running:  $HERDR"
    sleep 0.5
  done
  STARTED=1
}

# bun, which the plugin install provided (plugin/bun.sh).
find_bun() {
  if command -v bun >/dev/null 2>&1; then BUN=$(command -v bun)
  elif [ -x "$HOME/.bun/bin/bun" ]; then BUN="$HOME/.bun/bin/bun"
  else fail "bun was not found after the plugin install; its output above says why."
  fi
}

service_up() {
  # Any Shahi can answer /api/meta. Reuse the plugin's authenticated probe,
  # with this installation's private key, so another service on the port is
  # refused before claiming it is ready or trying to mint a pairing code.
  status=0
  (cd "$ROOT" && SHAHI_ENV_FILE="$CONFIG/.env" "$BUN" -e '
    import { existsSync } from "node:fs";
    import { whoAnswers } from "./plugin/shahi.ts";
    import { readEnvFile } from "./server/lib/secrets.ts";
    import { parsePort } from "./server/lib/config.ts";
    if (!existsSync(process.env.SHAHI_ENV_FILE)) process.exit(1);
    const env = readEnvFile(process.env.SHAHI_ENV_FILE);
    let port;
    try { port = parsePort(env.get("PORT")); }
    catch (error) { console.error(error.message); process.exit(3); }
    const who = await whoAnswers(`http://${env.get("HOST") || "127.0.0.1"}:${port}`, env);
    process.exit(who === "ours" ? 0 : who === "other" ? 2 : 1);
  ') || status=$?
  if [ "$status" = 2 ]; then
    fail "another program is answering on Shahi's configured port and refused this install's session key. Put PORT=<a free port> in $CONFIG/.env, then run:  $HERDR plugin action invoke shahi.restart"
  fi
  [ "$status" != 3 ] || fail "check PORT in $CONFIG/.env, then run this again."
  [ "$status" = 0 ]
}

# When this script started herdr, herdr's startup hook restarts Shahi's
# service a moment later, and pairing codes live in the service's memory: a
# code minted from the process about to be replaced was refused when scanned.
# That is every re-run after a reboot, and it failed 5 times in 10 on a fresh
# Debian VM (before the public launch). So wait for herdr's log to show this
# start's hook finished. A herdr whose log cannot be read is not waited for.
wait_for_startup_hook() {
  [ "${STARTED:-0}" = 1 ] || return 0
  deadline=$(($(date +%s) + 60))
  while :; do
    since=$((STARTED_AT * 1000 - 1000)) found=0
    "$HERDR" plugin log list --plugin shahi 2>/dev/null | SINCE=$since "$BUN" -e '
      let d; try { d = await Bun.stdin.json(); } catch { process.exit(2); }
      const logs = (d.result ?? d).logs;
      if (!Array.isArray(logs)) process.exit(2);
      const done = logs.some((l) => l.event === "startup" && l.started_unix_ms >= Number(process.env.SINCE) && l.finished_unix_ms);
      process.exit(done ? 0 : 1);' || found=$?
    case $found in 0|2) return 0 ;; esac
    [ "$(date +%s)" -lt "$deadline" ] || return 0
    sleep 0.5
  done
}

wait_for_service() {
  CONFIG=$("$HERDR" plugin config-dir shahi)
  ROOT=$("$HERDR" plugin list --json | "$BUN" -e 'const d = await Bun.stdin.json(); const p = (d.result ?? d).plugins.find((x) => x.plugin_id === "shahi"); console.log(p?.plugin_root ?? "")')
  [ -n "$ROOT" ] || fail "herdr does not report where the Shahi plugin is installed."
  # A disabled plugin stays disabled. Pairing should not silently re-enable
  # an installation the owner deliberately stopped.
  enabled=$("$HERDR" plugin list --json | "$BUN" -e 'const d = await Bun.stdin.json(); const p = (d.result ?? d).plugins.find((x) => x.plugin_id === "shahi"); console.log(p?.enabled === false ? "no" : "yes")')
  [ "$enabled" != no ] || fail "the Shahi plugin is disabled. Enable it with:  $HERDR plugin enable shahi   then run this again."
  wait_for_startup_hook
  service_up && { say "Shahi's service is running."; return; }
  # A herdr that was already running did not run the startup hook just now.
  [ "$STARTED" = 1 ] || "$HERDR" plugin action invoke shahi.restart >/dev/null 2>&1 || true
  step "Starting Shahi's service"
  deadline=$(($(date +%s) + 60))
  until service_up; do
    if [ "$(date +%s)" -ge "$deadline" ]; then
      fail "Shahi's service did not answer within a minute. Its log:  $HERDR plugin log list --plugin shahi"
    fi
    sleep 0.5
  done
  say "Shahi's service is running."
}

# The code is the last thing printed. Terminal.app and GNOME Terminal open at
# 80×24, and the lines that used to follow it scrolled its top out of sight;
# pair.ts draws it to fit, and says so when the window cannot hold it.
pair() {
  step "Pair your phone"
  # Said plainly: after a restart nothing brings herdr back, and the phone only
  # says herdr is offline (fresh-VM run before the public launch).
  say "Your phone reaches your agents while herdr runs here. After you scan, open it:  $HERDR"
  say "herdr does not start by itself: after restarting this computer, run herdr again."
  if [ "${PATH_HINT:-0}" = 1 ]; then
    # Ubuntu and Debian add ~/.local/bin at the next login once it exists, so
    # "add this to your profile" was wrong there; a new terminal is enough.
    say "This terminal cannot find herdr by name yet. Open a new terminal; if it still cannot, add this line to your shell's profile:"
    say "  export PATH=\"$BIN_DIR:\$PATH\""
  fi
  say "To pair another phone later, run this line again."
  say ""
  say "Scan this code in the Shahi app, or in https://getshahi.dev/pwa/ on any phone."
  say "No app yet? It is free on the App Store: https://apps.apple.com/app/id6813370698"
  (cd "$ROOT" && SHAHI_ENV_FILE="$CONFIG/.env" "$BUN" run server/scripts/pair.ts --no-copy) ||
    fail "the pairing code could not be made. Try:  $HERDR plugin action invoke shahi.status"
}

main() {
  say "Installing Shahi: see and answer your coding agents from your phone."
  platform
  need_tools
  find_herdr
  install_plugin
  start_herdr
  find_bun
  wait_for_service
  pair
}

# Everything above is a definition. Nothing runs until this line, so a download
# cut short runs nothing.
main "$@"