#!/bin/sh
# Mode installer -- download and install Mode (server + TUI) from a release tarball.
#
# Usage:
#   curl -fsSL https://raw.githubusercontent.com/gotmode/mode/main/install.sh | sh
#   curl -fsSL https://raw.githubusercontent.com/gotmode/mode/main/install.sh | sh -s -- --version 0.2.0
#   curl -fsSL https://gotmode.sh | sh
#
# Custom hosting:
#   curl -fsSL https://raw.githubusercontent.com/gotmode/mode/main/install.sh | sh -s -- --base-url https://dl.example.com/releases
#   curl -fsSL https://gotmode.sh | sh -s -- --channel beta
#
# Environment variables:
#   MODE_VERSION      -- version to install (default: latest stable from manifest)
#   MODE_INSTALL      -- install directory (default: ~/.config/mode)
#   MODE_BASE_URL     -- base URL for release downloads and version manifest
#   MODE_CHANNEL      -- release channel: stable, beta, alpha, rc (default: stable)

set -eu

REPO="gotmode/mode"
INSTALL_DIR="${MODE_INSTALL:-$HOME/.config/mode}"
VERSION="${MODE_VERSION:-}"
BASE_URL="${MODE_BASE_URL:-https://dl.gotmode.sh}"
CHANNEL="${MODE_CHANNEL:-stable}"

# -------------------------------------------------------------------
# Helpers
# -------------------------------------------------------------------

info()  { printf "\033[1;34m==>\033[0m %s\n" "$1"; }
warn()  { printf "\033[1;33mWARN:\033[0m %s\n" "$1" >&2; }
error() { printf "\033[1;31mERROR:\033[0m %s\n" "$1" >&2; exit 1; }

need_cmd() {
  if ! command -v "$1" >/dev/null 2>&1; then
    error "Required command '$1' not found. Please install it and retry."
  fi
}

# -------------------------------------------------------------------
# Detect OS and architecture
# -------------------------------------------------------------------

detect_platform() {
  OS="$(uname -s | tr '[:upper:]' '[:lower:]')"
  ARCH="$(uname -m)"

  case "$OS" in
    linux)  OS="linux" ;;
    darwin) OS="darwin" ;;
    *)      error "Unsupported operating system: $OS" ;;
  esac

  case "$ARCH" in
    x86_64)  ARCH="amd64" ;;
    amd64)   ARCH="amd64" ;;
    aarch64) ARCH="arm64" ;;
    arm64)   ARCH="arm64" ;;
    *)       error "Unsupported architecture: $ARCH" ;;
  esac

  PLATFORM="${OS}-${ARCH}"
}

# -------------------------------------------------------------------
# Parse arguments
# -------------------------------------------------------------------

parse_args() {
  while [ $# -gt 0 ]; do
    case "$1" in
      --version)   VERSION="$2"; shift 2 ;;
      --version=*) VERSION="${1#--version=}"; shift ;;
      --base-url)   BASE_URL="$2"; shift 2 ;;
      --base-url=*) BASE_URL="${1#--base-url=}"; shift ;;
      --channel)   CHANNEL="$2"; shift 2 ;;
      --channel=*) CHANNEL="${1#--channel=}"; shift ;;
      *) shift ;;
    esac
  done
}

# -------------------------------------------------------------------
# Resolve version
# -------------------------------------------------------------------

resolve_version() {
  if [ -n "$VERSION" ]; then
    # Explicit version provided -- use it directly.
    return
  fi

  case "$CHANNEL" in
    stable|alpha|beta|rc) ;;
    *) error "Unknown channel: ${CHANNEL}. Use stable, alpha, beta, or rc." ;;
  esac

  info "Detecting latest ${CHANNEL} version..."

  # Fetch the versions manifest from the download host.
  # The manifest is a JSON file mapping channel names to version strings:
  #   { "stable": "0.1.0", "alpha": "0.1.0-alpha.1", "beta": null, "rc": null }
  MANIFEST_URL="${BASE_URL%/}/versions.json"
  MANIFEST="$(curl -fsSL "$MANIFEST_URL" 2>/dev/null)" || true

  if [ -n "$MANIFEST" ]; then
    # Extract the version for the requested channel from the JSON.
    # Handles both "channel": "version" and "channel": null.
    VERSION="$(printf '%s' "$MANIFEST" \
      | sed -n "s/.*\"${CHANNEL}\": *\"\([^\"]*\)\".*/\1/p")" || true
  fi

  if [ -z "$VERSION" ]; then
    error "Could not determine latest ${CHANNEL} version from ${MANIFEST_URL}.\n  Set MODE_VERSION or use --version to specify a version explicitly."
  fi
}

# -------------------------------------------------------------------
# Build download URL
# -------------------------------------------------------------------

build_download_url() {
  TARBALL="mode-v${VERSION}-${PLATFORM}.tar.gz"

  # Detect whether BASE_URL looks like a GitHub Releases URL or a
  # generic file host. GitHub uses /download/v<tag>/<file>; a plain
  # file server just serves /<file> directly.
  case "$BASE_URL" in
    *github.com/*/releases*)
      DOWNLOAD_URL="${BASE_URL}/download/v${VERSION}/${TARBALL}"
      ;;
    *)
      # Generic host -- expect tarballs served at <BASE_URL>/<file>.
      # Strip trailing slash for consistency.
      DOWNLOAD_URL="${BASE_URL%/}/${TARBALL}"
      ;;
  esac
}

# -------------------------------------------------------------------
# Download and extract
# -------------------------------------------------------------------

download_and_install() {
  need_cmd curl
  need_cmd tar

  TMP_DIR="$(mktemp -d)"
  trap 'rm -rf "$TMP_DIR"' EXIT

  info "Downloading Mode v${VERSION} for ${PLATFORM}..."
  info "  ${DOWNLOAD_URL}"

  HTTP_CODE="$(curl -fSL -w '%{http_code}' -o "${TMP_DIR}/${TARBALL}" "$DOWNLOAD_URL" 2>/dev/null)" || true

  if [ ! -f "${TMP_DIR}/${TARBALL}" ] || [ "$HTTP_CODE" = "404" ]; then
    error "Release not found: v${VERSION} for ${PLATFORM}.\n  Check available releases at ${BASE_URL}"
  fi

  info "Extracting to ${INSTALL_DIR}..."
  mkdir -p "$INSTALL_DIR"

  tar -xzf "${TMP_DIR}/${TARBALL}" -C "$TMP_DIR"

  # The tarball extracts to mode-v<VERSION>-<PLATFORM>/.
  EXTRACTED="${TMP_DIR}/mode-v${VERSION}-${PLATFORM}"

  if [ ! -d "$EXTRACTED" ]; then
    error "Unexpected tarball structure -- missing ${EXTRACTED}"
  fi

  # Copy into install directory, overwriting previous install.
  rm -rf "${INSTALL_DIR:?}/bin" "${INSTALL_DIR:?}/server"
  cp -R "${EXTRACTED}/bin"    "$INSTALL_DIR/bin"
  cp -R "${EXTRACTED}/server" "$INSTALL_DIR/server"

  chmod +x "$INSTALL_DIR/bin/mode"
  chmod +x "$INSTALL_DIR/server/bin/mode"

  # Create the sandbox directory (inert CWD for the daemon process).
  # If the LLM falls through to File.cwd!(), operations land here
  # instead of in the install tree or a user project.
  mkdir -p "$INSTALL_DIR/.sandbox"
}

# -------------------------------------------------------------------
# Shell PATH integration
# -------------------------------------------------------------------

configure_path() {
  BIN_PATH="$INSTALL_DIR/bin"

  # Make `mode` available for the verify step within this script.
  export PATH="${BIN_PATH}:${PATH}"

  # Check if already configured in the shell rc file.
  SHELL_NAME="$(basename "$SHELL")"
  case "$SHELL_NAME" in
    zsh)  RC_FILE="$HOME/.zshrc" ;;
    bash) RC_FILE="$HOME/.bashrc" ;;
    fish) RC_FILE="$HOME/.config/fish/config.fish" ;;
    *)    RC_FILE="" ;;
  esac

  PATH_LINE="export PATH=\"${BIN_PATH}:\$PATH\""
  NEEDS_RELOAD=false

  if [ -n "$RC_FILE" ]; then
    if [ "$SHELL_NAME" = "fish" ]; then
      PATH_LINE="set -gx PATH ${BIN_PATH} \$PATH"
    fi

    # Don't add if already present.
    if ! grep -qF "$BIN_PATH" "$RC_FILE" 2>/dev/null; then
      printf '\n# Mode\n%s\n' "$PATH_LINE" >> "$RC_FILE"
      info "Added ${BIN_PATH} to ${RC_FILE}"
      NEEDS_RELOAD=true
    fi
  else
    warn "Could not detect shell rc file. Add this to your shell profile:"
    warn "  ${PATH_LINE}"
    NEEDS_RELOAD=true
  fi
}

# -------------------------------------------------------------------
# Verify installation
# -------------------------------------------------------------------

verify() {
  info "Installed Mode v${VERSION} to ${INSTALL_DIR}"
  echo ""
  echo "  Binary:   ${INSTALL_DIR}/bin/mode"
  echo ""
  echo "  Usage:"
  echo "    mode             Launch TUI (auto-starts runtime)"
  echo "    mode stop        Stop the runtime daemon"
  echo "    mode status      Show daemon status"
  echo "    mode version     Print version info"
  echo ""

  if [ "$NEEDS_RELOAD" = true ] && [ -n "$RC_FILE" ]; then
    printf "\033[1;33m%s\033[0m\n" "  To start using mode, reload your shell:"
    echo ""
    if [ "$SHELL_NAME" = "fish" ]; then
      echo "    source ${RC_FILE}"
    else
      echo "    source ${RC_FILE}   # reload PATH in current session"
    fi
    echo ""
  fi
}

# -------------------------------------------------------------------
# Main
# -------------------------------------------------------------------

main() {
  parse_args "$@"
  detect_platform
  resolve_version
  build_download_url
  download_and_install
  configure_path
  verify
}

main "$@"