#!/usr/bin/env bash

set -u

AGENT_DIR="/OGP"
PIDFILE="${1:-/OGP/ogp_agent_run.pid}"
PREFS_FILE="$AGENT_DIR/Cfg/bash_prefs.cfg"
START_LOG_NATIVE="${GSP_AGENT_START_LOG_NATIVE:-}"
REPO_URL_DEFAULT="http://forge.runlevelsystems.com/dev/GSP.git"
REPO_BRANCH_DEFAULT="Panel-unstable"
RAW_AGENT_URL_DEFAULT="http://forge.runlevelsystems.com/dev/GSP/raw/branch/Panel-unstable/Agent-Windows/OGP64/OGP/ogp_agent.pl"
REPO_AGENT_PATH="Agent-Windows/OGP64/OGP/ogp_agent.pl"

warn() {
	printf 'WARNING: %s\n' "$*" >&2
}

fail() {
	printf 'ERROR: %s\n' "$*" >&2
	exit 1
}

setup_startup_log() {
	local default_log="/var/log/gsp_agent_start.log"
	local log_path="${default_log}"

	if [ -n "$START_LOG_NATIVE" ] && command -v cygpath >/dev/null 2>&1; then
		log_path="$(cygpath -u "$START_LOG_NATIVE" 2>/dev/null || printf '%s' "$default_log")"
	elif [ -n "$START_LOG_NATIVE" ]; then
		log_path="$START_LOG_NATIVE"
	fi

	mkdir -p "$(dirname "$log_path")" 2>/dev/null || true
	touch "$log_path" 2>/dev/null || true
	exec > >(tee -a "$log_path") 2>&1
	printf 'GSP Windows Agent startup log: %s\n' "$log_path"
	printf 'Cygwin root detected by batch: %s\n' "${GSP_AGENT_CYGWIN_ROOT:-unknown}"
}

normalize_text_files() {
	local root="$1"
	[ -d "$root" ] || return 0
	find "$root" -type f \( -name '*.pl' -o -name '*.pm' -o -name '*.sh' -o -name '*.cfg' \) -print0 2>/dev/null |
		while IFS= read -r -d '' file; do
			sed -i 's/\r$//' "$file" 2>/dev/null || warn "Could not normalize line endings for $file"
		done
}

normalize_bash_preferences() {
	[ -f "$PREFS_FILE" ] || return 0
	sed -i 's/\r$//' "$PREFS_FILE" 2>/dev/null || warn "Could not normalize CRLF in $PREFS_FILE"
	sed -i -E 's/^[[:space:]]+([A-Za-z_][A-Za-z0-9_]*=)/\1/' "$PREFS_FILE" 2>/dev/null || warn "Could not normalize assignments in $PREFS_FILE"
}

install_default_config_if_missing() {
	local target="$1"
	local template="$2"
	if [ -f "$target" ]; then
		return 0
	fi
	if [ ! -f "$template" ]; then
		warn "Missing template $template; cannot create $target"
		return 0
	fi
	mkdir -p "$(dirname "$target")" 2>/dev/null || {
		warn "Cannot create config directory for $target"
		return 0
	}
	cp "$template" "$target" 2>/dev/null || {
		warn "Cannot create default config $target from $template"
		return 0
	}
	sed -i 's/\r$//' "$target" 2>/dev/null || true
}

ensure_default_configs() {
	install_default_config_if_missing "$AGENT_DIR/Cfg/Config.pm" "$AGENT_DIR/Cfg/Config.pm.default"
	install_default_config_if_missing "$AGENT_DIR/Cfg/Preferences.pm" "$AGENT_DIR/Cfg/Preferences.pm.default"
	install_default_config_if_missing "$AGENT_DIR/Cfg/bash_prefs.cfg" "$AGENT_DIR/Cfg/bash_prefs.cfg.default"
	normalize_bash_preferences
}

validate_required_config() {
	if [ ! -f "$AGENT_DIR/Cfg/Config.pm" ]; then
		fail "Missing $AGENT_DIR/Cfg/Config.pm. Run agent_conf.sh or copy Config.pm.default and set the Panel agent key."
	fi
	if grep -Eq "CHANGE_ME_PANEL_AGENT_KEY|key[[:space:]]*=>[[:space:]]*''" "$AGENT_DIR/Cfg/Config.pm"; then
		fail "$AGENT_DIR/Cfg/Config.pm still contains placeholder values. Set key/listen settings to match the Panel remote server record."
	fi
}

load_agent_preferences() {
	agent_auto_update=0
	agent_update_repo_url="$REPO_URL_DEFAULT"
	agent_update_branch="$REPO_BRANCH_DEFAULT"
	agent_update_raw_url="$RAW_AGENT_URL_DEFAULT"

	if [ -f "$PREFS_FILE" ]; then
		# shellcheck disable=SC1090
		. "$PREFS_FILE"
	fi

	agent_auto_update="${agent_auto_update:-0}"
	agent_update_repo_url="${agent_update_repo_url:-$REPO_URL_DEFAULT}"
	agent_update_branch="${agent_update_branch:-$REPO_BRANCH_DEFAULT}"
	agent_update_raw_url="${agent_update_raw_url:-$RAW_AGENT_URL_DEFAULT}"
}

validate_agent_file() {
	local candidate="$1"
	[ -s "$candidate" ] || {
		warn "Candidate agent file is empty: $candidate"
		return 1
	}
	if head -5 "$candidate" | grep -Eiq '(<html|<!doctype|not found|404|forbidden|error)'; then
		warn "Candidate agent file looks like an HTTP error page or text response: $candidate"
		return 1
	fi
	if ! head -1 "$candidate" | grep -Eq '^#!.*perl'; then
		warn "Candidate agent file does not start with a Perl shebang: $candidate"
		return 1
	fi
	if ! grep -q 'use Cfg::Config' "$candidate"; then
		warn "Candidate agent file does not look like the GSP/OGP Perl agent: $candidate"
		return 1
	fi
	sed -i 's/\r$//' "$candidate" 2>/dev/null || true
	perl -c "$candidate" >/tmp/gsp-agent-perl-check.log 2>&1 || {
		warn "Candidate agent failed perl validation:"
		cat /tmp/gsp-agent-perl-check.log >&2 2>/dev/null || true
		return 1
	}
	return 0
}

download_agent_with_curl() {
	local target="$1"
	if ! command -v curl >/dev/null 2>&1; then
		return 1
	fi
	echo "Downloading Windows agent from $agent_update_raw_url..."
	curl -fsSL "$agent_update_raw_url" -o "$target"
}

download_agent_with_git() {
	local target="$1"
	if ! command -v git >/dev/null 2>&1; then
		return 1
	fi

	local repo_dir source_file
	repo_dir="$(dirname "$target")/repo"
	echo "Checking for Windows agent update from $agent_update_repo_url ($agent_update_branch)..."
	if ! git clone --depth 1 --branch "$agent_update_branch" "$agent_update_repo_url" "$repo_dir"; then
		return 1
	fi

	source_file="$repo_dir/$REPO_AGENT_PATH"
	if [ ! -f "$source_file" ]; then
		warn "Updated Windows agent source was not found at $REPO_AGENT_PATH"
		return 1
	fi
	cp "$source_file" "$target"
}

auto_update_windows_agent() {
	[ "$agent_auto_update" = "1" ] || {
		echo "Agent auto-update is disabled."
		return 0
	}

	local tmp_dir candidate_file target_file backup_file
	tmp_dir="$(mktemp -d /tmp/gsp-agent-update.XXXXXX 2>/dev/null)" || {
		warn "Could not create temporary update directory; skipping auto-update."
		return 0
	}
	candidate_file="$tmp_dir/ogp_agent.pl"
	target_file="$AGENT_DIR/ogp_agent.pl"
	backup_file="$AGENT_DIR/ogp_agent.pl.bak.$(date +%Y%m%d%H%M%S)"

	if ! download_agent_with_curl "$candidate_file"; then
		warn "curl download failed or curl is unavailable; trying git fallback."
		if ! download_agent_with_git "$candidate_file"; then
			warn "Agent auto-update download failed; using the current agent."
			rm -rf "$tmp_dir"
			return 0
		fi
	fi

	if ! validate_agent_file "$candidate_file"; then
		warn "Downloaded Windows agent was rejected; using the current agent."
		rm -rf "$tmp_dir"
		return 0
	fi

	if [ -f "$target_file" ] && ! validate_agent_file "$target_file"; then
		warn "Current Windows agent does not validate. Auto-update can still replace it if backup succeeds."
	fi

	if [ -f "$target_file" ]; then
		cp "$target_file" "$backup_file" 2>/dev/null || {
			warn "Could not backup $target_file; skipping auto-update."
			rm -rf "$tmp_dir"
			return 0
		}
	else
		warn "$target_file is missing; installing validated agent without a local backup."
		backup_file=""
	fi

	if ! cp "$candidate_file" "$target_file"; then
		warn "Could not copy updated Windows agent; restoring backup."
		[ -n "$backup_file" ] && cp "$backup_file" "$target_file" 2>/dev/null
		rm -rf "$tmp_dir"
		return 0
	fi

	if ! validate_agent_file "$target_file"; then
		warn "Updated Windows agent failed validation after install; restoring backup."
		[ -n "$backup_file" ] && cp "$backup_file" "$target_file" 2>/dev/null
		rm -rf "$tmp_dir"
		return 0
	fi

	echo "Windows agent auto-update completed."
	rm -rf "$tmp_dir"
	return 0
}

cd "$AGENT_DIR" || fail "Could not enter $AGENT_DIR. Is the Windows agent installed under Cygwin /OGP?"

setup_startup_log
normalize_text_files "$AGENT_DIR"
normalize_text_files "/Install"
ensure_default_configs
load_agent_preferences
auto_update_windows_agent
validate_required_config

echo "Validating $AGENT_DIR/ogp_agent.pl..."
validate_agent_file "$AGENT_DIR/ogp_agent.pl" || fail "Perl syntax/dependency validation failed. Install missing Cygwin Perl packages or restore a valid Windows agent file."

echo "Launching GSP Windows Agent..."
exec perl "$AGENT_DIR/ogp_agent.pl" -pidfile "$PIDFILE"