#!/usr/bin/env bash
# ─── Mosaic Stack Installer / Upgrader ────────────────────────────────────────
#
# Remote install (recommended):
#   bash <(curl -fsSL https://git.mosaicstack.dev/mosaic/mosaic-stack/raw/branch/main/tools/install.sh)
#
# Remote install (alternative — use -s -- to pass flags):
#   curl -fsSL https://git.mosaicstack.dev/mosaic/mosaic-stack/raw/branch/main/tools/install.sh | bash -s --
#   curl -fsSL ... | bash -s -- --check
#
# Local (from repo checkout):
#   bash tools/install.sh
#   bash tools/install.sh --check    # version check only
#
# Environment:
#   MOSAIC_REGISTRY  — npm registry URL  (default: Gitea instance)
#   MOSAIC_SCOPE     — npm scope          (default: @mosaic)
#   MOSAIC_PREFIX    — npm global prefix  (default: ~/.npm-global)
#   MOSAIC_NO_COLOR  — disable colour     (set to 1)
# ──────────────────────────────────────────────────────────────────────────────
#
# The entire script is wrapped in main() so that bash reads it fully into
# memory before execution — required for safe curl-pipe usage.

set -euo pipefail

main() {

# ─── constants ────────────────────────────────────────────────────────────────
REGISTRY="${MOSAIC_REGISTRY:-https://git.mosaicstack.dev/api/packages/mosaic/npm/}"
SCOPE="${MOSAIC_SCOPE:-@mosaic}"
PREFIX="${MOSAIC_PREFIX:-$HOME/.npm-global}"
CLI_PKG="${SCOPE}/cli"

# ─── colours ──────────────────────────────────────────────────────────────────
# Detect colour support: works in terminals and bash <(curl …), but correctly
# disables when piped through a non-tty (curl … | bash).
if [[ "${MOSAIC_NO_COLOR:-0}" == "1" ]] || ! [[ -t 1 ]]; then
  R="" G="" Y="" B="" C="" DIM="" RESET=""
else
  R=$'\033[0;31m' G=$'\033[0;32m' Y=$'\033[0;33m'
  B=$'\033[0;34m' C=$'\033[0;36m' DIM=$'\033[2m' RESET=$'\033[0m'
fi

info()  { echo "${B}ℹ${RESET}  $*"; }
ok()    { echo "${G}✔${RESET}  $*"; }
warn()  { echo "${Y}⚠${RESET}  $*"; }
fail()  { echo "${R}✖${RESET}  $*" >&2; }
dim()   { echo "${DIM}$*${RESET}"; }

# ─── helpers ──────────────────────────────────────────────────────────────────

require_cmd() {
  if ! command -v "$1" &>/dev/null; then
    fail "Required command not found: $1"
    echo "  Install it and re-run this script."
    exit 1
  fi
}

# Get the installed version of @mosaic/cli (empty string if not installed)
installed_version() {
  local json
  json="$(npm ls -g --depth=0 --json --prefix="$PREFIX" 2>/dev/null)" || true
  if [[ -n "$json" ]]; then
    # Feed json via heredoc, not stdin pipe — safe in curl-pipe context
    node -e "
      const d = JSON.parse(process.argv[1]);
      const v = d?.dependencies?.['${CLI_PKG}']?.version ?? '';
      process.stdout.write(v);
    " "$json" 2>/dev/null || true
  fi
}

# Get the latest published version from the registry
latest_version() {
  npm view "${CLI_PKG}" version --registry="$REGISTRY" 2>/dev/null || true
}

# Compare two semver strings: returns 0 (true) if $1 < $2
version_lt() {
  # Semver-aware comparison via node (handles pre-release correctly)
  node -e "
    const a=process.argv[1], b=process.argv[2];
    const sp = v => { const i=v.indexOf('-'); return i===-1 ? [v,null] : [v.slice(0,i),v.slice(i+1)]; };
    const [cA,pA]=sp(a.replace(/^v/,'')), [cB,pB]=sp(b.replace(/^v/,''));
    const nA=cA.split('.').map(Number), nB=cB.split('.').map(Number);
    for(let i=0;i<3;i++){if((nA[i]||0)<(nB[i]||0))process.exit(0);if((nA[i]||0)>(nB[i]||0))process.exit(1);}
    if(pA!==null&&pB===null)process.exit(0);
    if(pA===null)process.exit(1);
    if(pA<pB)process.exit(0);
    process.exit(1);
  " "$1" "$2" 2>/dev/null
}

# ─── preflight ────────────────────────────────────────────────────────────────

require_cmd node
require_cmd npm

NODE_MAJOR="$(node -e 'process.stdout.write(String(process.versions.node.split(".")[0]))')"
if [[ "$NODE_MAJOR" -lt 20 ]]; then
  fail "Node.js >= 20 required (found v$(node --version))"
  exit 1
fi

# ─── ensure prefix directory exists ──────────────────────────────────────────

if [[ ! -d "$PREFIX" ]]; then
  info "Creating global prefix directory: $PREFIX"
  mkdir -p "$PREFIX"/{bin,lib}
fi

# ─── ensure npmrc scope mapping ──────────────────────────────────────────────

NPMRC="$HOME/.npmrc"
SCOPE_LINE="${SCOPE}:registry=${REGISTRY}"

if ! grep -qF "$SCOPE_LINE" "$NPMRC" 2>/dev/null; then
  info "Adding ${SCOPE} registry to $NPMRC"
  echo "$SCOPE_LINE" >> "$NPMRC"
  ok "Registry configured"
fi

# Ensure prefix is set (only if no prefix= line exists yet)
if ! grep -qF "prefix=$PREFIX" "$NPMRC" 2>/dev/null; then
  if ! grep -q '^prefix=' "$NPMRC" 2>/dev/null; then
    echo "prefix=$PREFIX" >> "$NPMRC"
    info "Set npm global prefix to $PREFIX"
  fi
fi

# Ensure PREFIX/bin is on PATH
if [[ ":$PATH:" != *":$PREFIX/bin:"* ]]; then
  warn "$PREFIX/bin is not on your PATH"
  dim "  Add to your shell rc:  export PATH=\"$PREFIX/bin:\$PATH\""
fi

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

info "Checking versions…"

CURRENT="$(installed_version)"
LATEST="$(latest_version)"

if [[ -z "$LATEST" ]]; then
  fail "Could not reach registry at $REGISTRY"
  fail "Check network connectivity and registry URL."
  exit 1
fi

echo ""
if [[ -n "$CURRENT" ]]; then
  dim "  Installed: ${CLI_PKG}@${CURRENT}"
else
  dim "  Installed: (none)"
fi
dim "  Latest:    ${CLI_PKG}@${LATEST}"
echo ""

# --check flag: just report, don't install
if [[ "${1:-}" == "--check" ]]; then
  if [[ -z "$CURRENT" ]]; then
    warn "Not installed. Run without --check to install."
    exit 1
  elif [[ "$CURRENT" == "$LATEST" ]]; then
    ok "Up to date."
    exit 0
  elif version_lt "$CURRENT" "$LATEST"; then
    warn "Update available: $CURRENT → $LATEST"
    exit 2
  else
    ok "Up to date (or ahead of registry)."
    exit 0
  fi
fi

# ─── install / upgrade ──────────────────────────────────────────────────────

if [[ -z "$CURRENT" ]]; then
  info "Installing ${CLI_PKG}@${LATEST}…"
elif [[ "$CURRENT" == "$LATEST" ]]; then
  ok "Already at latest version ($LATEST). Nothing to do."
  exit 0
elif version_lt "$CURRENT" "$LATEST"; then
  info "Upgrading ${CLI_PKG}: $CURRENT → $LATEST…"
else
  ok "Installed version ($CURRENT) is at or ahead of registry ($LATEST)."
  exit 0
fi

npm install -g "${CLI_PKG}@${LATEST}" \
  --registry="$REGISTRY" \
  --prefix="$PREFIX" \
  2>&1 | sed 's/^/  /'

echo ""
ok "Mosaic CLI installed: $(installed_version)"
dim "  Binary: $PREFIX/bin/mosaic"

# ─── post-install: run wizard if first install ───────────────────────────────

if [[ -z "$CURRENT" ]]; then
  echo ""
  info "First install detected."
  if [[ -t 0 ]] && [[ -t 1 ]]; then
    echo "  Run ${C}mosaic wizard${RESET} to set up your configuration."
  else
    dim "  Run 'mosaic wizard' to set up your configuration."
  fi
fi

echo ""
ok "Done."

} # end main

main "$@"