#!/bin/sh
# stackplay installer — https://stackplay.run
# Usage: curl -fsSL https://stackplay.run | sh
#
# Environment variables:
#   STACKPLAY_VERSION      Pin a specific version (e.g. "0.3.0" or "v0.3.0")
#   STACKPLAY_INSTALL_DIR  Override install directory (default: ~/.local/bin)
#   STACKPLAY_QUIET        Set to 1 to suppress non-error output

set -eu

#region helpers

BOLD=""
DIM=""
GREEN=""
CYAN=""
RED=""
YELLOW=""
RESET=""

setup_colors() {
  if [ -t 1 ] && [ -z "${NO_COLOR:-}" ]; then
    BOLD="\033[1m"
    DIM="\033[2m"
    GREEN="\033[32m"
    CYAN="\033[36m"
    RED="\033[31m"
    YELLOW="\033[33m"
    RESET="\033[0m"
  fi
}

info() {
  if [ -z "${STACKPLAY_QUIET:-}" ]; then
    printf "${DIM}%s${RESET}\n" "$1" >&2
  fi
}

success() {
  printf "${GREEN}%s${RESET}\n" "$1" >&2
}

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

warn() {
  printf "${YELLOW}warning:${RESET} %s\n" "$1" >&2
}

command_exists() {
  command -v "$1" >/dev/null 2>&1
}

#endregion

#region platform detection

detect_platform() {
  OS="$(uname -s)"
  case "$OS" in
    Darwin) OS="darwin" ;;
    Linux)  OS="linux" ;;
    MINGW*|MSYS*|CYGWIN*)
      error "Windows is not yet supported. Track progress at https://github.com/saulsharma/stackplay/issues" ;;
    *)
      error "Unsupported operating system: $OS" ;;
  esac

  ARCH="$(uname -m)"
  case "$ARCH" in
    x86_64|amd64) ARCH="amd64" ;;
    aarch64|arm64) ARCH="arm64" ;;
    *)
      error "Unsupported architecture: $ARCH" ;;
  esac
}

#endregion

#region network

fetch() {
  url="$1"
  dest="$2"
  if command_exists curl; then
    curl -fsSL "$url" -o "$dest"
  elif command_exists wget; then
    wget -qO "$dest" "$url"
  else
    error "curl or wget is required"
  fi
}

fetch_stdout() {
  url="$1"
  if command_exists curl; then
    curl -fsSL "$url"
  elif command_exists wget; then
    wget -qO- "$url"
  else
    error "curl or wget is required"
  fi
}

#endregion

#region version resolution

resolve_version() {
  if [ -n "${STACKPLAY_VERSION:-}" ]; then
    # Strip leading v
    VERSION="${STACKPLAY_VERSION#v}"
    TAG="v${VERSION}"
    return
  fi

  info "Finding latest version..."
  TAG=$(fetch_stdout "https://api.github.com/repos/$REPO/releases/latest" \
    | grep '"tag_name"' | head -1 | cut -d'"' -f4) || true

  if [ -z "$TAG" ]; then
    error "Could not determine latest version. Set STACKPLAY_VERSION to install a specific version."
  fi

  VERSION="${TAG#v}"
}

#endregion

#region checksum verification

verify_checksum() {
  tarball_path="$1"
  tarball_name="$2"

  if ! command_exists shasum && ! command_exists sha256sum; then
    warn "Neither shasum nor sha256sum found — skipping checksum verification"
    return
  fi

  info "Verifying checksum..."
  checksum_url="$BASE_URL/checksums.txt"

  checksums=$(fetch_stdout "$checksum_url" 2>/dev/null) || {
    warn "Could not fetch checksums — skipping verification"
    return
  }

  expected=$(echo "$checksums" | grep "$tarball_name" | head -1 | awk '{print $1}')
  if [ -z "$expected" ]; then
    warn "No checksum found for $tarball_name — skipping verification"
    return
  fi

  if command_exists sha256sum; then
    actual=$(sha256sum "$tarball_path" | awk '{print $1}')
  else
    actual=$(shasum -a 256 "$tarball_path" | awk '{print $1}')
  fi

  if [ "$expected" != "$actual" ]; then
    error "Checksum mismatch!
  Expected: $expected
  Actual:   $actual
This could indicate a corrupted download or a tampered release."
  fi
}

#endregion

#region install

install_binaries() {
  tmp="$1"
  install_dir="$2"

  if [ ! -f "$tmp/stackplay" ]; then
    error "Release archive did not contain the stackplay binary"
  fi

  mkdir -p "$install_dir"

  cp "$tmp/stackplay" "$install_dir/stackplay"
  chmod +x "$install_dir/stackplay"

  if [ -f "$tmp/stackplay-tui" ]; then
    cp "$tmp/stackplay-tui" "$install_dir/stackplay-tui"
    chmod +x "$install_dir/stackplay-tui"
  else
    warn "Release archive did not contain stackplay-tui; CLI installed without the TUI"
  fi
}

#endregion

#region path helpers

shell_name() {
  basename "${SHELL:-/bin/sh}"
}

print_path_instructions() {
  install_dir="$1"

  # Check if already in PATH
  case ":${PATH}:" in
    *":${install_dir}:"*) return ;;
  esac

  shell=$(shell_name)
  printf "\n"
  warn "$install_dir is not in your PATH"
  printf "\n"
  printf "  Add it by running:\n\n"

  case "$shell" in
    zsh)
      printf "    ${CYAN}echo 'export PATH=\"%s:\$PATH\"' >> ~/.zshrc && source ~/.zshrc${RESET}\n" "$install_dir"
      ;;
    bash)
      rc="~/.bashrc"
      if [ "$(uname -s)" = "Darwin" ]; then
        rc="~/.bash_profile"
      fi
      printf "    ${CYAN}echo 'export PATH=\"%s:\$PATH\"' >> %s && source %s${RESET}\n" "$install_dir" "$rc" "$rc"
      ;;
    fish)
      printf "    ${CYAN}fish_add_path %s${RESET}\n" "$install_dir"
      ;;
    *)
      printf "    ${CYAN}export PATH=\"%s:\$PATH\"${RESET}\n" "$install_dir"
      ;;
  esac
  printf "\n"
}

#endregion

#region main

main() {
  setup_colors

  REPO="saulsharma/stackplay"
  INSTALL_DIR="${STACKPLAY_INSTALL_DIR:-$HOME/.local/bin}"

  detect_platform
  info "Platform: ${OS}/${ARCH}"

  resolve_version
  info "Version:  ${VERSION}"

  BASE_URL="https://github.com/$REPO/releases/download/$TAG"
  TARBALL="stackplay_${VERSION}_${OS}_${ARCH}.tar.gz"
  URL="$BASE_URL/$TARBALL"

  # Download
  TMP=$(mktemp -d)
  trap 'rm -rf "$TMP"' EXIT

  info "Downloading stackplay ${VERSION}..."
  fetch "$URL" "$TMP/$TARBALL"

  # Verify
  verify_checksum "$TMP/$TARBALL" "$TARBALL"

  # Extract
  tar xzf "$TMP/$TARBALL" -C "$TMP"

  # Install
  install_binaries "$TMP" "$INSTALL_DIR"

  # Done
  printf "\n"
  success "  stackplay ${VERSION} installed to ${INSTALL_DIR}"
  printf "\n"

  print_path_instructions "$INSTALL_DIR"

  printf "  ${BOLD}Get started:${RESET}\n\n"
  printf "    ${CYAN}cd your-project${RESET}\n"
  printf "    ${CYAN}stackplay${RESET}\n\n"
  printf "  ${BOLD}Using an AI coding agent?${RESET} Install the stackplay skill for\n"
  printf "  Claude Code, Cursor, Codex, opencode, and others:\n\n"
  printf "    ${CYAN}npx skills add saulsharma/stackplay${RESET}\n\n"
  printf "  ${DIM}https://github.com/saulsharma/stackplay${RESET}\n\n"
}

main "$@"

#endregion