#!/bin/sh /etc/rc.common
# SPDX-License-Identifier: Apache-2.0
# CDN Cache Proxy Init Script
# Copyright (C) 2025 CyberMind.fr

START=90
STOP=10
USE_PROCD=1

CONF_FILE="/var/etc/cdn-cache-nginx.conf"
PID_FILE="/var/run/cdn-cache.pid"

validate_section() {
	uci_load_validate cdn-cache main "$1" "$2" \
		'enabled:bool:0' \
		'cache_dir:string:/var/cache/cdn' \
		'cache_size:uinteger:1024' \
		'max_object_size:uinteger:512' \
		'cache_valid:uinteger:1440' \
		'listen_port:port:3128' \
		'transparent:bool:0' \
		'log_level:string:warn'
}

generate_nginx_config() {
	local cache_dir="$1"
	local cache_size="$2"
	local max_object="$3"
	local cache_valid="$4"
	local listen_port="$5"
	
	mkdir -p "$(dirname $CONF_FILE)"
	mkdir -p "$cache_dir"
	mkdir -p /var/log/cdn-cache
	
	cat > "$CONF_FILE" << EOF
# CDN Cache Nginx Configuration
# Auto-generated - Do not edit

worker_processes auto;
pid $PID_FILE;
error_log /var/log/cdn-cache/error.log $log_level;

events {
    worker_connections 1024;
    use epoll;
    multi_accept on;
}

http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;
    
    log_format cache '\$time_local|\$remote_addr|\$request|\$status|\$body_bytes_sent|\$upstream_cache_status|\$host';
    access_log /var/log/cdn-cache/access.log cache;
    
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    
    # Cache zone configuration
    proxy_cache_path $cache_dir levels=1:2 keys_zone=cdn_cache:64m 
                     max_size=${cache_size}m inactive=7d use_temp_path=off;
    proxy_temp_path $cache_dir/temp;
    
    # Cache settings
    proxy_cache_valid 200 ${cache_valid}m;
    proxy_cache_valid 301 302 10m;
    proxy_cache_valid 404 1m;
    proxy_cache_use_stale error timeout updating http_500 http_502 http_503 http_504;
    proxy_cache_lock on;
    proxy_cache_lock_timeout 5s;
    
    # Upstream settings
    proxy_connect_timeout 10s;
    proxy_read_timeout 60s;
    proxy_send_timeout 60s;
    proxy_buffering on;
    proxy_buffer_size 16k;
    proxy_buffers 8 32k;
    proxy_max_temp_file_size ${max_object}m;
    
    # Resolver for dynamic upstream
    resolver 8.8.8.8 8.8.4.4 valid=300s ipv6=off;
    resolver_timeout 5s;
    
    server {
        listen $listen_port;
        server_name _;
        
        # Health check endpoint
        location /cdn-cache-health {
            return 200 'OK';
            add_header Content-Type text/plain;
        }
        
        # Stats endpoint
        location /cdn-cache-stats {
            stub_status;
            allow 127.0.0.1;
            deny all;
        }
        
        # Proxy all requests
        location / {
            proxy_pass http://\$host\$request_uri;
            proxy_cache cdn_cache;
            proxy_cache_key \$scheme\$host\$request_uri;
            
            # Add cache status header
            add_header X-Cache-Status \$upstream_cache_status;
            add_header X-Cache-Date \$upstream_http_date;
            
            # Forward headers
            proxy_set_header Host \$host;
            proxy_set_header X-Real-IP \$remote_addr;
            proxy_set_header X-Forwarded-For \$proxy_add_x_forwarded_for;
            
            # Cache specific content types aggressively
            proxy_cache_valid 200 301 302 ${cache_valid}m;
            
            # Bypass cache for certain requests
            proxy_cache_bypass \$http_pragma \$http_authorization;
            proxy_no_cache \$http_pragma \$http_authorization;
        }
        
        # Special handling for update services
        location ~* \.(exe|msu|cab|msi|deb|rpm|apk|pkg\.tar\.zst)$ {
            proxy_pass http://\$host\$request_uri;
            proxy_cache cdn_cache;
            proxy_cache_key \$scheme\$host\$request_uri;
            proxy_cache_valid 200 10080m;
            add_header X-Cache-Status \$upstream_cache_status;
            proxy_set_header Host \$host;
        }
        
        # Static content with longer cache
        location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff|woff2|ttf|eot)$ {
            proxy_pass http://\$host\$request_uri;
            proxy_cache cdn_cache;
            proxy_cache_key \$scheme\$host\$request_uri;
            proxy_cache_valid 200 1440m;
            add_header X-Cache-Status \$upstream_cache_status;
            proxy_set_header Host \$host;
        }
    }
}
EOF
}

start_service() {
	validate_section main start_cdn_cache
}

start_cdn_cache() {
	[ "$2" = 0 ] || {
		echo "Validation failed" >&2
		return 1
	}
	
	[ "$enabled" = "1" ] || {
		echo "CDN Cache is disabled"
		return 0
	}
	
	generate_nginx_config "$cache_dir" "$cache_size" "$max_object_size" \
		"$cache_valid" "$listen_port"
	
	procd_open_instance cdn-cache
	procd_set_param command /usr/sbin/nginx -c "$CONF_FILE" -g "daemon off;"
	procd_set_param respawn
	procd_set_param stdout 1
	procd_set_param stderr 1
	procd_set_param pidfile "$PID_FILE"
	procd_close_instance
	
	logger -t cdn-cache "CDN Cache proxy started on port $listen_port"
}

stop_service() {
	logger -t cdn-cache "CDN Cache proxy stopped"
}

reload_service() {
	stop
	start
}

service_triggers() {
	procd_add_reload_trigger "cdn-cache"
}