#!/usr/bin/env sh
# nina install script
# Run:  curl -fsSL kepr.uk/nina/install.sh | sh
# Or:   NINA_INSTALL_DIR=/usr/local/bin sh install.sh
#
# Downloads the pre-built binary from Kepr for your platform.
# Falls back to building from source (requires Zig 0.16+) if unavailable.

set -e

RELEASES_URL="https://kepr.uk/api/nina/releases/latest"
SOURCE_URL="https://kepr.uk/nina/archive/HEAD.tar.gz"
INSTALL_DIR="${NINA_INSTALL_DIR:-$HOME/.local/bin}"
MIN_ZIG_MINOR=16

# Detect platform
os="$(uname -s)"
arch="$(uname -m)"
case "${os}-${arch}" in
  Linux-x86_64)               platform="linux-x86_64"  ;;
  Linux-aarch64|Linux-arm64)  platform="linux-aarch64" ;;
  Darwin-arm64)               platform="macos-aarch64" ;;
  Darwin-x86_64)              platform="macos-x86_64"  ;;
  *)
    printf 'nina install: unsupported platform %s-%s\n' "$os" "$arch" >&2
    printf '  build from source with Zig 0.%s+:\n' "$MIN_ZIG_MINOR" >&2
    printf '    zig build -Doptimize=ReleaseSafe\n' >&2
    exit 1 ;;
esac

have() { command -v "$1" >/dev/null 2>&1; }
say()  { printf 'nina install: %s\n' "$1"; }
die()  { say "error: $1" >&2; exit 1; }

fetch_text() {
  if have curl;   then curl -fsSL "$1"
  elif have wget; then wget -qO- "$1"
  else die "curl or wget is required"; fi
}

fetch_file() {
  if have curl;   then curl -fsSL "$1" -o "$2"
  elif have wget; then wget -qO  "$2" "$1"
  else die "curl or wget is required"; fi
}

# ── binary install from Kepr ─────────────────────────────────────────────────

install_binary() {
  say "fetching release metadata..."
  meta="$(fetch_text "$RELEASES_URL" 2>/dev/null)" || return 1
  [ -n "$meta" ] || return 1

  if have python3; then
    version="$(printf '%s' "$meta" | python3 -c "
import sys, json
d = json.load(sys.stdin)
print(d.get('version') or '')
" 2>/dev/null)"
    dl_url="$(printf '%s' "$meta" | python3 -c "
import sys, json
d = json.load(sys.stdin)
print((d.get('platforms') or {}).get('${platform}', {}).get('url') or '')
" 2>/dev/null)"
    cksum="$(printf '%s' "$meta" | python3 -c "
import sys, json
d = json.load(sys.stdin)
p = (d.get('platforms') or {}).get('${platform}', {})
raw = p.get('blake3') or p.get('checksum') or ''
print(raw[len('blake3:'):] if raw.startswith('blake3:') else raw)
" 2>/dev/null)"
  elif have jq; then
    version="$(printf '%s' "$meta" | jq -r '.version // empty')"
    dl_url="$(printf '%s' "$meta" | jq -r ".platforms.\"${platform}\".url // empty")"
    cksum_raw="$(printf '%s' "$meta" | jq -r ".platforms.\"${platform}\".blake3 // .platforms.\"${platform}\".checksum // empty")"
    cksum="${cksum_raw#blake3:}"
  else
    # Minimal grep/sed fallback for compact JSON
    version="$(printf '%s' "$meta" | grep -o '"version":"[^"]*"' | sed 's/"version":"//;s/"//')"
    plat_block="$(printf '%s' "$meta" | grep -o "\"${platform}\":{[^}]*}" | head -1)"
    dl_url="$(printf '%s' "$plat_block" | grep -o '"url":"[^"]*"' | sed 's/"url":"//;s/"//')"
    cksum=""
  fi

  [ -n "$dl_url" ] || return 1
  [ -n "$version" ] || version="latest"

  say "downloading nina ${version} for ${platform}..."
  tmpfile="$(mktemp /tmp/nina.XXXXXX)"
  fetch_file "$dl_url" "$tmpfile" || { rm -f "$tmpfile"; return 1; }

  if [ -n "$cksum" ] && have b3sum; then
    actual="$(b3sum --no-names "$tmpfile" 2>/dev/null | awk '{print $1}')"
    if [ "$actual" != "$cksum" ]; then
      say "blake3 checksum mismatch — aborting"
      rm -f "$tmpfile"
      return 1
    fi
    say "checksum verified"
  fi

  chmod +x "$tmpfile"
  mkdir -p "$INSTALL_DIR"
  mv "$tmpfile" "${INSTALL_DIR}/nina"
  say "installed nina ${version} → ${INSTALL_DIR}/nina"
  return 0
}

# ── Zig version check ─────────────────────────────────────────────────────────

check_zig() {
  if ! have zig; then
    say ""
    say "Zig not found. Building nina from source requires Zig 0.${MIN_ZIG_MINOR} or later."
    say ""
    say "  NixOS:"
    say "    nix profile install 'nixpkgs#zig_0_16'   # if your channel has it"
    say "    nix-shell -p zig_0_16 --run 'sh install.sh'"
    say "    # or add 'pkgs.zig_0_16' to environment.systemPackages and rebuild"
    say ""
    say "  Direct download: https://ziglang.org/download/"
    say ""
    die "Zig 0.${MIN_ZIG_MINOR}+ required for source build"
  fi

  zig_ver="$(zig version 2>/dev/null)"
  major="$(printf '%s' "$zig_ver" | cut -d. -f1)"
  minor="$(printf '%s' "$zig_ver" | cut -d. -f2)"

  ok=0
  [ "$major" -ge 1 ] 2>/dev/null && ok=1
  [ "$major" -eq 0 ] 2>/dev/null && [ "$minor" -ge "$MIN_ZIG_MINOR" ] 2>/dev/null && ok=1

  if [ "$ok" -ne 1 ]; then
    say ""
    say "Found zig ${zig_ver}, but nina requires Zig 0.${MIN_ZIG_MINOR} or later."
    say ""
    say "  NixOS: the system 'zig' package is ${zig_ver}. To get 0.16:"
    say "    nix profile install 'nixpkgs#zig_0_16'"
    say "    nix-shell -p zig_0_16 --run 'sh install.sh'"
    say "    # or check nixpkgs-unstable if your stable channel lacks zig_0_16"
    say ""
    say "  Direct download: https://ziglang.org/download/"
    say ""
    die "Zig 0.${MIN_ZIG_MINOR}+ required; found ${zig_ver}"
  fi

  say "zig ${zig_ver} found"
}

# ── source build fallback ─────────────────────────────────────────────────────

build_from_source() {
  say "falling back to build from source..."
  check_zig

  if [ -f "build.zig" ] && [ -f "src/main.zig" ]; then
    srcdir="."
  else
    say "fetching source archive from Kepr..."
    srcdir="$(mktemp -d /tmp/nina-src.XXXXXX)"
    fetch_file "$SOURCE_URL" "${srcdir}/nina.tar.gz" \
      || die "could not download source archive"
    tar -xzf "${srcdir}/nina.tar.gz" -C "$srcdir" --strip-components=1 \
      || die "could not extract source archive"
  fi

  say "building (this may take a moment)..."
  (cd "$srcdir" && zig build -Doptimize=ReleaseSafe) \
    || die "build failed — see output above for details"

  mkdir -p "$INSTALL_DIR"
  cp "${srcdir}/zig-out/bin/nina" "${INSTALL_DIR}/nina"
  chmod +x "${INSTALL_DIR}/nina"
  say "installed from source → ${INSTALL_DIR}/nina"
}

# ── PATH reminder ─────────────────────────────────────────────────────────────

check_path() {
  case ":${PATH}:" in
    *":${INSTALL_DIR}:"*) ;;
    *)
      say ""
      say "${INSTALL_DIR} is not in your PATH. Add it:"
      say "  export PATH=\"\${PATH}:${INSTALL_DIR}\""
      say "  echo 'export PATH=\"\${PATH}:${INSTALL_DIR}\"' >> ~/.bashrc"
      say "  # NixOS: add '${INSTALL_DIR}' to environment.sessionVariables in configuration.nix"
      ;;
  esac
}

# ── main ──────────────────────────────────────────────────────────────────────

if install_binary; then
  check_path
  exit 0
fi

say "pre-built binary unavailable for ${platform} — trying source build"
build_from_source
check_path