#!/usr/bin/env sh
# Bootstrap: curl -fsSL https://install.visudo.icu | sh
# Supports: curl -fsSL <url> | sh -s -- [install.sh flags...]
set -eu

# --- Colors (POSIX-safe, respects NO_COLOR) ---

if [ -n "${NO_COLOR:-}" ] || [ ! -t 1 ]; then
	RED='' GREEN='' DIM='' NC=''
else
	RED='\033[0;31m'
	GREEN='\033[0;32m'
	DIM='\033[2m'
	NC='\033[0m'
fi

info()  { printf "  %b●%b %s\n" "$GREEN" "$NC" "$*"; }
error() { printf "  %b●%b %s\n" "$RED" "$NC" "$*" >&2; }

# --- Preflight ---

if [ "$(id -u)" = "0" ]; then
	error "Do not run this as root"
	exit 1
fi

if [ "$(uname)" != "Linux" ]; then
	error "This installer only supports Linux"
	exit 1
fi

if ! command -v bash >/dev/null 2>&1; then
	error "bash is required"
	exit 1
fi

if ! command -v curl >/dev/null 2>&1; then
	error "curl is required — install it first, then re-run"
	exit 1
fi

# --- Parse arguments (preserve quoting via positional params) ---

BASE_URL="${DOTFILES_URL:-https://install.visudo.icu}"
DOTFILES_DIR="$HOME/.dotfiles"

# POSIX sh has no arrays — use a sentinel to rebuild $@ in place, preserving
# quoting/whitespace through the final `exec bash … "$@"`. Forwarded args
# are appended past the sentinel; the loop stops when it reaches it.
_argv_sentinel="__BOOTSTRAP_ARGV_END__"
set -- "$@" "$_argv_sentinel"
while [ "$1" != "$_argv_sentinel" ]; do
	case "$1" in
		--dir|-d)
			[ $# -ge 2 ] || { error "$1 requires a value"; exit 1; }
			DOTFILES_DIR="$2"
			shift 2
			;;
		*)
			# Rotate this arg past the sentinel — it will be forwarded to install.sh.
			set -- "$@" "$1"
			shift
			;;
	esac
done
shift  # drop the sentinel; $@ is now exactly what we forward.

# --- Download and verify (with retry for CDN cache skew) ---

info "Downloading dotfiles..."

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

# Fetch the tarball + checksum and compare. Returns 0 on match, 1 on mismatch,
# 2 on hard failure (download/parse error). On mismatch we retry once with
# cache-busting query strings to recover from CDN edge cache skew between
# `.tar.gz` and `.tar.gz.sha256` during a deploy propagation window.
fetch_and_verify() {
	suffix="${1:-}"
	tar_url="$BASE_URL/dotfiles.tar.gz$suffix"
	sum_url="$BASE_URL/dotfiles.tar.gz.sha256$suffix"

	if ! curl -fsSL -H 'Cache-Control: no-cache' -H 'Pragma: no-cache' \
		"$tar_url" -o "$tmpdir/dotfiles.tar.gz"; then
		error "Failed to download dotfiles from $tar_url"
		return 2
	fi

	if ! curl -fsSL --connect-timeout 5 -H 'Cache-Control: no-cache' -H 'Pragma: no-cache' \
		"$sum_url" -o "$tmpdir/expected.sha256" 2>/dev/null; then
		error "Checksum file not available — cannot verify download integrity"
		error "If this persists, download manually from $BASE_URL"
		return 2
	fi

	expected_checksum=$(awk '{print $1; exit}' "$tmpdir/expected.sha256")
	# Validate that the checksum file actually contains a SHA-256 (64 hex chars).
	# Without this, a CDN serving the wrong content (e.g. an HTML error page or the
	# wrong asset) would be silently accepted as a checksum.
	if ! printf '%s' "$expected_checksum" | grep -qE '^[0-9a-fA-F]{64}$'; then
		error "Checksum file at $sum_url is malformed"
		error "(server returned non-SHA-256 content — try again or report to maintainer)"
		return 2
	fi
	actual_checksum=$(sha256sum "$tmpdir/dotfiles.tar.gz" | awk '{print $1}')
	if [ "$expected_checksum" != "$actual_checksum" ]; then
		return 1
	fi
	return 0
}

if fetch_and_verify ""; then
	info "Checksum verified"
else
	rc=$?
	if [ "$rc" = "2" ]; then
		exit 1
	fi
	# Mismatch — likely CDN cache skew between the two assets. Retry once with
	# a cache-busting query string to force the edge to revalidate both files.
	info "Checksum mismatch — refreshing cache and retrying..."
	sleep 2
	if fetch_and_verify "?cb=$(date +%s)-$$"; then
		info "Checksum verified"
	else
		error "Checksum verification failed — download may be corrupted or tampered with"
		printf "  Expected: %s\n" "$expected_checksum" >&2
		printf "  Got:      %s\n" "$actual_checksum" >&2
		error "If this persists after a few minutes, report it: $BASE_URL"
		exit 1
	fi
fi

# --- Extract ---

if [ -d "$DOTFILES_DIR" ]; then
	info "Existing install found at $DOTFILES_DIR — updating..."
	rm -rf "$DOTFILES_DIR"
fi

mkdir -p "$DOTFILES_DIR"
if ! tar -xzf "$tmpdir/dotfiles.tar.gz" -C "$DOTFILES_DIR"; then
	error "Failed to extract dotfiles"
	exit 1
fi

# --- Verify download integrity ---

if [ ! -f "$DOTFILES_DIR/install.sh" ]; then
	error "Download appears corrupted — install.sh not found in $DOTFILES_DIR"
	exit 1
fi

# --- Launch installer ---

info "Launching installer..."
if [ $# -gt 0 ]; then
	printf "  %b%s %s%b\n\n" "$DIM" "$DOTFILES_DIR/install.sh" "$*" "$NC"
else
	printf "  %b%s%b\n\n" "$DIM" "$DOTFILES_DIR/install.sh" "$NC"
fi
exec bash "$DOTFILES_DIR/install.sh" "$@"