[MM-29157] Cloud invoices logic (#16056)

* Cloud invoices logic

This commit includes all the code needed to get and print invoices
from CWS

api4/cloud.go

@@ -4,9 +4,13 @@
 package api4
 
 import (
+	"bytes"
+	"encoding/binary"
 	"encoding/json"
+	"fmt"
 	"io/ioutil"
 	"net/http"
+	"time"
 
 	"github.com/mattermost/mattermost-server/v5/audit"
 	"github.com/mattermost/mattermost-server/v5/model"
@@ -30,6 +34,8 @@ func (api *API) InitCloud() {
 
 	// GET /api/v4/cloud/subscription
 	api.BaseRoutes.Cloud.Handle("/subscription", api.ApiSessionRequired(getSubscription)).Methods("GET")
+	api.BaseRoutes.Cloud.Handle("/subscription/invoices", api.ApiSessionRequired(getInvoicesForSubscription)).Methods("GET")
+	api.BaseRoutes.Cloud.Handle("/subscription/invoices/{invoice_id:in_[A-Za-z0-9]+}/pdf", api.ApiSessionRequired(getSubscriptionInvoicePDF)).Methods("GET")
 }
 
 func getSubscription(c *Context, w http.ResponseWriter, r *http.Request) {
@@ -254,3 +260,68 @@ func confirmCustomerPayment(c *Context, w http.ResponseWriter, r *http.Request)
 
 	ReturnStatusOK(w)
 }
+
+func getInvoicesForSubscription(c *Context, w http.ResponseWriter, r *http.Request) {
+	if c.App.Srv().License() == nil || !*c.App.Srv().License().Features.Cloud {
+		c.Err = model.NewAppError("Api4.getInvoicesForSubscription", "api.cloud.license_error", nil, "", http.StatusNotImplemented)
+		return
+	}
+
+	if !c.App.SessionHasPermissionTo(*c.App.Session(), model.PERMISSION_MANAGE_SYSTEM) {
+		c.SetPermissionError(model.PERMISSION_MANAGE_SYSTEM)
+		return
+	}
+
+	invoices, appErr := c.App.Cloud().GetInvoicesForSubscription()
+	if appErr != nil {
+		c.Err = model.NewAppError("Api4.getInvoicesForSubscription", "api.cloud.request_error", nil, appErr.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	json, err := json.Marshal(invoices)
+	if err != nil {
+		c.Err = model.NewAppError("Api4.getInvoicesForSubscription", "api.cloud.app_error", nil, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	w.Write(json)
+}
+
+func getSubscriptionInvoicePDF(c *Context, w http.ResponseWriter, r *http.Request) {
+	if c.App.Srv().License() == nil || !*c.App.Srv().License().Features.Cloud {
+		c.Err = model.NewAppError("Api4.getSuscriptionInvoicePDF", "api.cloud.license_error", nil, "", http.StatusNotImplemented)
+		return
+	}
+
+	c.RequireInvoiceId()
+	if c.Err != nil {
+		return
+	}
+
+	if !c.App.SessionHasPermissionTo(*c.App.Session(), model.PERMISSION_MANAGE_SYSTEM) {
+		c.SetPermissionError(model.PERMISSION_MANAGE_SYSTEM)
+		return
+	}
+
+	pdfData, appErr := c.App.Cloud().GetInvoicePDF(c.Params.InvoiceId)
+	if appErr != nil {
+		c.Err = model.NewAppError("Api4.getSuscriptionInvoicePDF", "api.cloud.request_error", nil, appErr.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	err := writeFileResponse(
+		fmt.Sprintf("%s.pdf", c.Params.InvoiceId),
+		"application/pdf",
+		int64(binary.Size(pdfData)),
+		time.Now(),
+		*c.App.Config().ServiceSettings.WebserverMode,
+		bytes.NewReader(pdfData),
+		false,
+		w,
+		r,
+	)
+	if err != nil {
+		c.Err = err
+		return
+	}
+}