digraph G {
overlap=false
nodesep=2

subgraph client {
label = "Client";
node[color=red];
"Customer"
"Freelancer"
}

subgraph endpoints {
label = "API Endpoints";
node[color=turquoise]
"/"
"/customer/$freelancer/template/$templateName"
"/customer/$freelancer/template/$templateName/request"

"/freelancer/$freelancer/inbox"
"/freelancer/$freelancer/requests/$requestID" 
"/freelancer/$freelancer/requests/$requestID/accept" 
"/freelancer/$freelancer/requests/$requestID/decline"

"/freelancer/$freelancer/createInvoice"

"/freelancer/login"

"/freelancer/$freelancer/requests/$requestID/finalProduct"

}

subgraph backend {
label = "Backend";
node[color=blue]
"Oauth2 Authorization Server"
UpFrontPaymentSetup
UpFrontPaymentWatcher
OnDeliverPaymentSetup
OnDeliverPaymentWatcher
FreelancerPayOut
deliveryHandler
"Download Link Maker"
}

subgraph foreign {
node[color=yellow]
label = "Foreign APIs";
Stripe
}


subgraph selfhosted {
node[color=orange]
label = "Self-Hosted software";
"Email Server"
BTCPayServer
}

subgraph filesystem {
node[color=black]
label = "Filesystem";
"Freelancer Data"
"commission database"
}

//Customer Interface
////GET
"Customer" -> {"/" "/customer/$freelancer/template/$templateName"} [label="GET Request"]
{"/" "/customer/$freelancer/template/$templateName"} -> Customer [label="HTML"]
////POST
"Customer" -> {"/customer/$freelancer/template/$templateName/request"} [label = "POST Request"]
{"/customer/$freelancer/template/$templateName/request"} -> "Customer" [label="HTML"]

//Freelancer Interface
"Freelancer" -> {"/freelancer/$freelancer/inbox" "/freelancer/$freelancer/requests/$requestID/accept" "/freelancer/$freelancer/requests/$requestID/decline"} [label="GET Request"]
{"/freelancer/$freelancer/inbox" "/freelancer/$freelancer/requests/$requestID/accept" "/freelancer/$freelancer/requests/$requestID/decline"} -> "Freelancer" [label="HTML"]

//Populating with Freelancer Data
"Freelancer Data" -> "/customer/$freelancer/template/$templateName" [label = "Commission Templates"]

//Template System
"/customer/$freelancer/template/$templateName/request" -> {"commission database"} [label = "store Commission Request Data"]
"commission database" -> "/freelancer/$freelancer/requests/$requestID" [label = "read Commission Request Data"]
"/freelancer/$freelancer/requests/$requestID/accept" -> "commission database" [label = "change $accepted value to true"]
"/freelancer/$freelancer/requests/$requestID/decline" -> "commission database" [label = "change $accepted value to false"]
"/freelancer/$freelancer/requests/$requestID/decline" -> "Email Server" -> "Customer" [label = "Declining letter"]

//Invoice System
Freelancer -> "/freelancer/$freelancer/createInvoice" [label = "POST Request"]
"/freelancer/$freelancer/createInvoice" -> "commission database" [label = "store Commission Request Data"]

//Log in
Freelancer -> "/freelancer/login" 
"/freelancer/login" -> "Oauth2 Authorization Server" [label = "POST Request"]
"Oauth2 Authorization Server" -> "Freelancer" [label = "Authorization Token"]

//Payment verification
"commission database" -> UpFrontPaymentSetup [label="Periodic queries of new approved commissions"]
UpFrontPaymentSetup -> {BTCPayServer Stripe} [label="API request"]
{BTCPayServer Stripe} -> UpFrontPaymentSetup [label="Invoice IDs"]

UpFrontPaymentSetup -> "commission database" [label="write $invoiceID of commission"]

"commission database" -> UpFrontPaymentWatcher [label="periodic queries of $invoiceIDs of unpaid upfront commissions"]

{BTCPayServer Stripe} -> UpFrontPaymentWatcher [label="Payment recieved on invoice"]
UpFrontPaymentWatcher -> Freelancer [label="Notification that payment for commission has been recieved"]

{Stripe BTCPayServer} -> Customer [label = "Email containing invoice data"]

//Delivery

////Freelancer Upload
Freelancer -> "/freelancer/$freelancer/requests/$requestID/finalProduct" [label="POST Request"]
"/freelancer/$freelancer/requests/$requestID/finalProduct" -> deliveryHandler [label="notification to start handling the delivery of the product"]
"/freelancer/$freelancer/requests/$requestID/finalProduct" -> "Download Link Maker" [label="Notification to hand the Freelancer a link to his product"]
"Download Link Maker" -> "/freelancer/$freelancer/requests/$requestID/finalProduct" -> Freelancer [label="Link to final product"]

////Conditional on delivery handling
"commission database" -> deliveryHandler [label="check if delivery is pay-on-deliver or not"]
deliveryHandler -> {"Email Server"} -> Customer [label="Final Product delivered directly if not pay-on-deliver"]

deliveryHandler -> OnDeliverPaymentSetup [label="notify that this will require payment on deliver"]
"commission database" -> OnDeliverPaymentSetup -> {BTCPayServer Stripe}[label="Amount owed and who to invoice"]
{BTCPayServer Stripe} -> "Invoice IDs" -> "commission database" [label="write $invoiceID of commission"]
"commission database" -> OnDeliverPaymentWatcher [label="periodic queries of $invoiceIDs of unpaid delivery commissions"]
{BTCPayServer Stripe} -> OnDeliverPaymentWatcher [label="Payment recieved on invoice"]
OnDeliverPaymentWatcher -> Freelancer [label="Notification that payment for commission has been recieved"]
OnDeliverPaymentWatcher -> {"Email Server"} -> Customer [label="Final Product delivered"]

//Set up system for payouts to users

{OnDeliverPaymentWatcher deliveryHandler} -> "FreelancerPayOut"
"FreelancerPayOut" -> {Stripe BTCPayServer} [label = "Send a call out to send money to the freelancer"]
{Stripe BTCPayServer} -> "FreelancerPayOut" [label = "Confirmed money has been sent to user"]
"FreelancerPayOut" -> "Freelancer" [label = "Notification money has been sent"]
}