include /etc/nginx/conf.d/include/cors;
include /etc/nginx/conf.d/include/proxy-buffer;
include /etc/nginx/conf.d/include/proxy-cache-downloads;
include /etc/nginx/conf.d/include/track-download;

limit_conn downloads_by_ip 100; # ddos protection: max 100 downloads at a time

# ensure that skylink that we pass around is base64 encoded (transform base32 encoded ones)
# this is important because we want only one format in cache keys and logs
set_by_lua_block $skylink { return require("skynet.skylink").parse(ngx.var.skylink) }

# $skylink_v1 and $skylink_v2 variables default to the same value but in case the requested skylink was:
# a) skylink v1 - it would not matter, no additional logic is executed
# b) skylink v2 - in a lua block below we will resolve the skylink v2 into skylink v1 and update
#      $skylink_v1 variable so then the proxy request to skyd can be cached in nginx (proxy_cache_key
#      in proxy-cache-downloads includes $skylink_v1 as a part of the cache key)
set $skylink_v1 $skylink;
set $skylink_v2 $skylink;

# variable for Skynet-Proof header that we need to inject
# into a response if the request was for skylink v2
set $skynet_proof '';

# default download rate to unlimited
set $limit_rate 0;

access_by_lua_block {
    local accounts = require("skynet.account")
    if accounts.accounts_enabled() then
        -- check if portal is in authenticated only mode
        if accounts.is_access_unauthorized() then
            return accounts.exit_access_unauthorized()
        end

        -- check if portal is in subscription only mode
        if accounts.is_access_forbidden() then
            return accounts.exit_access_forbidden()
        end
    end
}

header_filter_by_lua_block {
    ngx.header["Skynet-Portal-Api"] = ngx.var.scheme .. "://" .. ngx.var.skynet_portal_domain
    ngx.header["Skynet-Server-Api"] = ngx.var.scheme .. "://" .. ngx.var.skynet_server_domain
}

limit_rate_after 512k;
limit_rate $limit_rate;

proxy_read_timeout 600;
proxy_set_header User-Agent: Sia-Agent;

# in case the requested skylink was v2 and we already resolved it to skylink v1, we are going to pass resolved
# skylink v1 to skyd to save that extra skylink v2 lookup in skyd but in turn, in case skyd returns a redirect
# we need to rewrite the skylink v1 to skylink v2 in the location header with proxy_redirect
proxy_redirect $skylink_v1 $skylink_v2;
proxy_pass http://sia:9980/skynet/skylink/$skylink_v1$path$is_args$args;