#!/bin/sh
# Mercury installer — https://mercury-cli.ai/install
#
#   curl -fsSL https://mercury-cli.ai/install | sh
#
# Downloads the release archive for this machine from GitHub Releases, checks
# its SHA-256 against the release's checksum file, unpacks it, and runs the
# archive's own `mercury install` — the user-local installer that puts the
# release under ~/.mercury/versions/ and a `mercury` command in ~/.local/bin,
# then puts that folder on your PATH (one line in your shell's rc file) when it
# is not already. No administrator access; nothing outside your home.
# Rerunning is safe.
#
# Knobs (all optional):
#   MERCURY_VERSION           a release tag (default: the newest release)
#   MERCURY_INSTALL_BASE_URL  where the assets live (default: the GitHub release)
#   MERCURY_INSTALL_ARGS      extra args for `mercury install` (e.g. --force)
set -eu

REPO="Whq02/MercuryCLI"
say() { printf '%s\n' "$*"; }
die() { printf 'mercury install: %s\n' "$*" >&2; exit 1; }

need() { command -v "$1" >/dev/null 2>&1 || die "this installer needs '$1' — install it and rerun"; }
need curl; need tar

# ── which archive ────────────────────────────────────────────────────────────
os=$(uname -s); arch=$(uname -m)
case "$os/$arch" in
  Darwin/arm64)          target=macos-arm64 ;;
  Darwin/x86_64)         target=macos-x64 ;;
  Linux/x86_64|Linux/amd64) target=linux-x64 ;;
  Linux/aarch64|Linux/arm64) die "no Linux arm64 build yet — build from source: https://github.com/$REPO" ;;
  MINGW*|MSYS*|CYGWIN*|Windows*) die "on Windows use PowerShell:  irm https://mercury-cli.ai/install.ps1 | iex" ;;
  *) die "unsupported platform: $os $arch" ;;
esac

# ── which version ────────────────────────────────────────────────────────────
version=${MERCURY_VERSION:-}
if [ -z "$version" ]; then
  # The newest release, pre-releases included (the /latest endpoint hides them).
  version=$(curl -fsSL "https://api.github.com/repos/$REPO/releases?per_page=1" 2>/dev/null \
    | grep -m1 '"tag_name"' | sed 's/.*"tag_name": *"\([^"]*\)".*/\1/' || true)
  [ -n "$version" ] || die "could not find the newest release at github.com/$REPO — set MERCURY_VERSION=vX.Y.Z"
fi
case "$version" in v*) ;; *) version="v$version" ;; esac
asset="mercury-$version-$target.tar.gz"
base=${MERCURY_INSTALL_BASE_URL:-"https://github.com/$REPO/releases/download/$version"}

# ── download + verify ────────────────────────────────────────────────────────
tmp=$(mktemp -d "${TMPDIR:-/tmp}/mercury-install.XXXXXX")
trap 'rm -rf "$tmp"' EXIT
say "Mercury $version for $target"
say "  downloading $asset"
curl -fsSL --retry 3 -o "$tmp/$asset" "$base/$asset" || die "download failed: $base/$asset"
curl -fsSL --retry 3 -o "$tmp/SHA256SUMS.txt" "$base/SHA256SUMS.txt" || die "download failed: $base/SHA256SUMS.txt"
want=$(grep " $asset\$" "$tmp/SHA256SUMS.txt" | awk '{print $1}' | head -1)
[ -n "$want" ] || die "$asset is not listed in SHA256SUMS.txt"
if command -v sha256sum >/dev/null 2>&1; then got=$(sha256sum "$tmp/$asset" | awk '{print $1}')
else got=$(shasum -a 256 "$tmp/$asset" | awk '{print $1}'); fi
[ "$got" = "$want" ] || die "checksum mismatch for $asset (got $got, want $want) — nothing installed"
say "  checksum ok"

# ── unpack + the archive's own installer ─────────────────────────────────────
tar -xzf "$tmp/$asset" -C "$tmp"
[ -x "$tmp/mercury/mercury" ] || die "the archive has no launcher at mercury/mercury"
say "  installing (user-local; no administrator access)"
# shellcheck disable=SC2086
"$tmp/mercury/mercury" install ${MERCURY_INSTALL_ARGS:-}

# ── the command on PATH ──────────────────────────────────────────────────────
# ~/.local/bin is not on a fresh macOS PATH (and reaches a Linux PATH only at
# the next login). One guarded line in the login shell's rc file makes
# `mercury` work in every new terminal.
bin="$HOME/.local/bin"
case ":${PATH}:" in
  *":$bin:"*)
    say ""
    say "Done. Run:  mercury" ;;
  *)
    line="export PATH=\"\$HOME/.local/bin:\$PATH\""
    case "$(basename "${SHELL:-sh}")" in
      zsh)  rc="$HOME/.zshrc" ;;
      bash) if [ "$os" = Darwin ]; then rc="$HOME/.bash_profile"; else rc="$HOME/.bashrc"; fi ;;
      fish) rc="$HOME/.config/fish/config.fish"; line="fish_add_path \"\$HOME/.local/bin\"" ;;
      *)    rc="$HOME/.profile" ;;
    esac
    if [ -f "$rc" ] && grep -Fq '.local/bin' "$rc" 2>/dev/null; then
      say ""
      say "Done. $rc already names ~/.local/bin — open a new terminal and run:  mercury"
    else
      mkdir -p "$(dirname "$rc")"
      printf '\n# mercury: the user-local command\n%s\n' "$line" >> "$rc"
      say ""
      say "Done. Added ~/.local/bin to PATH in $rc — open a new terminal and run:  mercury"
      say "      (this terminal: $line)"
    fi ;;
esac