#!/bin/bash

# ====== Configuration =====
download_dir="$HOME/etc/hoststool" # 卸载时需要注意系统权限组的路径与用户管理员路径不同，但都必须是root用户
if [ ! -d "$download_dir" ]; then
	sudo mkdir -p $download_dir
fi
source="https://raw.githubusercontent.com/JohyC/Hosts/main/hosts.txt"

# ====== Functions =====
showHelp() {
	echo "-u [source_url]	update github hosts. You can specify a custom host source"
	echo "-rm	remove appended hosts in /etc/hosts file"
	echo "-b	backup /etc/hosts to /etc/hosts.backup"
	echo "-r	recover hosts.backup to hosts"
	echo "-l	list files in /etc which contains \"hosts\""
}

remove(){
	# Remove old content
	begin=$(sed -n  '/# ==== Github Start ====/=' /etc/hosts | awk 'NR==1{print}')
	end=$(sed -n  '/# ==== Github End ====/=' /etc/hosts | awk 'END{print}')
	echo "[INFO] Removing old hosts. Start at line \"${begin}\", End at line \"${end}\""
	sudo sh -c "cat /etc/hosts | sed \"${begin},${end}d\" > ${download_dir}/hosts.tmp"
	if [ $? -ne 0 ]; then
		## Trip failed
		echo "[INFO] 当前 Host中 无旧的 Github Host 标记可清除"
	else
		## Trip succeed, move result
		echo "[INFO] 清除旧的 Github Host 标记"
		sudo cp /etc/hosts /etc/hosts.backup && sudo cp ${download_dir}/hosts.tmp /etc/hosts;
	fi

}

# ====== Main =====
if [ $# -eq 0 ]; then showHelp;exit 0;fi

case "$1" in
	-l)
		ls /etc | grep hosts;
		exit 0;;
	-b) 
		sudo cp /etc/hosts /etc/hosts.backup;
		exit 0;;
	-r) 
		sudo cp /etc/hosts.backup /etc/hosts;
		exit 0;;
	-rm)
		remove;
		exit 0;;		
	-u) 
		if [ $2 ]; then source=$2;fi
		sudo curl -o ${download_dir}/hosts ${source};
		if [ $? -ne 0 ]; then
			echo "[ERROR] 获取远程 host 出错，请尝试更换 source 或检查 $download_dir 读写权限"
			osascript -e 'display notification "获取远程 host 出错，请尝试更换 source" with title "hoststool"'
			exit 1
		fi
		
		# Validate host content length
		lines=$(awk '{print NR}' ${download_dir}/hosts | tail -n1)
		if [ $lines -lt 10 ]
		then
			echo '[ERROR] source无效，请更换为可用hosts源'
			osascript -e 'display notification "source无效，请更换为可用hosts源" with title "hoststool"'
			sudo rm ${download_dir}/hosts
			exit 1
		fi

		# remove old contents
		remove

		# Add new hosts
		sudo bash -c "echo '# ==== Github Start ====' >> /etc/hosts" # Add github host
		if [ $? -ne 0 ]; then
			echo "[ERROR] 无root权限，请尝试运行脚本手动输入密码"
			osascript -e 'display notification "无root权限，请尝试运行脚本手动输入密码" with title "hoststool"'
			sudo rm ${download_dir}/hosts.tmp
			sudo rm ${download_dir}/hosts
			exit 1;
		fi
		sudo bash -c "echo \"# Updated at $(date)\" >> /etc/hosts" # Add github host
		sudo bash -c "cat ${download_dir}/hosts >> /etc/hosts";
		sudo bash -c "echo '# ==== Github End ====' >> /etc/hosts"
		sudo rm ${download_dir}/hosts.tmp
		sudo rm ${download_dir}/hosts

		echo "[INFO] Github Hosts 块更新于 $(date)"
		osascript -e 'display notification "Github Hosts 已更新" with title "hoststool"'
		exit 0;;
	-h|--help)
		showHelp;
		exit 0;;
	*)
		echo "[ERROR] Unknown command";
		showHelp;
		exit 1;;
esac