From 3b491c0c7f8f3e1134d00d24950c18cb5e3281b4 Mon Sep 17 00:00:00 2001
From: Matti R <matti@mdranta.net>
Date: Mon, 1 Feb 2021 15:12:04 -0500
Subject: [PATCH] Initial Commit

---
 .gitignore         |   2 +
 lgtmbot.yml        |  16 +++++
 lgtmbot/handler.go | 149 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 167 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 lgtmbot.yml
 create mode 100644 lgtmbot/handler.go

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..942d901
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+template
+build
diff --git a/lgtmbot.yml b/lgtmbot.yml
new file mode 100644
index 0000000..ccdb9a2
--- /dev/null
+++ b/lgtmbot.yml
@@ -0,0 +1,16 @@
+version: 1.0
+provider:
+  name: openfaas
+  gateway: http://127.0.0.1:8080
+functions:
+  lgtmbot:
+    lang: golang-middleware
+    handler: ./lgtmbot
+    image: techknowlogick/lgtmbot:latest
+    secrets:
+      - webhook-secret # random string generated by you
+      - gitea-host # host of your gitea instance, ex. https://gitea.example.com/
+      - gitea-token # gitea api token generated from https://gitea.example.com/user/settings/applications
+    build_args:
+      GO111MODULE: on
+
diff --git a/lgtmbot/handler.go b/lgtmbot/handler.go
new file mode 100644
index 0000000..9fdb8e6
--- /dev/null
+++ b/lgtmbot/handler.go
@@ -0,0 +1,149 @@
+package function
+
+import (
+	"code.gitea.io/sdk/gitea"
+	"io/ioutil"
+	"net/http"
+	"strings"
+
+	scm "github.com/jenkins-x/go-scm/scm"
+	giteaWebhook "github.com/jenkins-x/go-scm/scm/driver/gitea"
+)
+
+func Handle(w http.ResponseWriter, r *http.Request) {
+	webhookService := giteaWebhook.NewWebHookService()
+	payload, err := webhookService.Parse(r, getWebhookSecret)
+	if err != nil {
+		// webhook failed to parse, either due to invalid secret or other reason
+		w.WriteHeader(http.StatusBadRequest)
+		return
+	}
+
+	owner := ""
+	repo := ""
+	index := int64(0)
+	// validate that we received a PR Hook
+	switch v := payload.(type) {
+	case *scm.PullRequestHook:
+		owner = v.Repo.Namespace
+		repo = v.Repo.Name
+		index = int64(v.PullRequest.Number)
+	default:
+		// unexpected hook passed
+		w.WriteHeader(http.StatusBadRequest)
+		return
+	}
+	if index == 0 {
+		// unexpected hook passed, PR should have an index
+		w.WriteHeader(http.StatusBadRequest)
+		return
+	}
+
+	// get gitea secrets & setup client
+	giteaHost, err := getAPISecret("gitea-host")
+	if err != nil {
+		// failed to get secret
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	giteaToken, err := getAPISecret("gitea-token")
+	if err != nil {
+		// failed to get secret
+		w.WriteHeader(http.StatusInternalServerError)
+	}
+	giteaClient, err := gitea.NewClient(string(giteaHost), gitea.SetToken(string(giteaToken)))
+	if err != nil {
+		// failed to setup gitea client
+		w.WriteHeader(http.StatusInternalServerError)
+	}
+
+	// fetch PR and approvals
+	pr, _, err := giteaClient.GetPullRequest(owner, repo, index)
+	if err != nil {
+		// failed to fetch PR
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	approvals, _, err := giteaClient.ListPullReviews(owner, repo, index, gitea.ListPullReviewsOptions{})
+	if err != nil {
+		// failed to fetch approvals
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	// determine which LGTM label should be used
+	approvalCount := 0
+	for _, approval := range approvals {
+		if approval.State == gitea.ReviewStateApproved {
+			approvalCount++
+		}
+	}
+	labelNeeded := "lgtm/done"
+	switch approvalCount {
+	case 0:
+		labelNeeded = "lgtm/need 2"
+	case 1:
+		labelNeeded = "lgtm/need 1"
+	}
+
+	// loop thourgh existing labels to determine if an update is needed
+	needUpdate := true
+	for _, label := range pr.Labels {
+		if !strings.HasPrefix(label.Name, "lgtm/") {
+			continue
+		}
+		if label.Name == labelNeeded {
+			needUpdate = false
+			continue
+		}
+		// if label starts with "lgtm/" but isn't the correct label
+		giteaClient.DeleteIssueLabel(owner, repo, index, label.ID)
+	}
+	if !needUpdate {
+		// no label changes required
+		w.WriteHeader(http.StatusOK)
+		return
+	}
+
+	// if needed label not set, then set it
+	// fetch ID of labelNeeded
+	giteaLabels, _, err := giteaClient.ListRepoLabels(owner, repo, gitea.ListLabelsOptions{})
+	if err != nil {
+		// failed to fetch labels
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	labelID := int64(0)
+	for _, label := range giteaLabels {
+		if label.Name == labelNeeded {
+			labelID = label.ID
+		}
+	}
+	if labelID == 0 {
+		// failed to find label, TODO: create label
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	// set label on PR
+	createSlice := []int64{int64(labelID)}
+	_, _, err = giteaClient.AddIssueLabels(owner, repo, index, gitea.IssueLabelsOption{createSlice})
+	if err != nil {
+		// failed to set label
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	// all fine
+	w.WriteHeader(http.StatusOK)
+	return
+}
+
+func getWebhookSecret(scm.Webhook) (string, error) {
+	secret, err := getAPISecret("webhook-secret")
+	return string(secret), err
+}
+
+func getAPISecret(secretName string) (secretBytes []byte, err error) {
+	// read from the openfaas secrets folder
+	return ioutil.ReadFile("/var/openfaas/secrets/" + secretName)
+}