From 47c570855fa54ddfcf4a11ceae1c2312130d63e2 Mon Sep 17 00:00:00 2001
From: "Gustavo L de Mello (Guz)" <contact@guz.one>
Date: Mon, 7 Oct 2024 15:40:26 -0300
Subject: [PATCH] feat(router): error handling of routes

---
 router/rerrors/400s.go   | 16 +++++++++++
 router/rerrors/500s.go   | 12 +++++++++
 router/rerrors/errors.go | 57 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 85 insertions(+)
 create mode 100644 router/rerrors/400s.go
 create mode 100644 router/rerrors/500s.go
 create mode 100644 router/rerrors/errors.go

diff --git a/router/rerrors/400s.go b/router/rerrors/400s.go
new file mode 100644
index 0000000..3f9be6c
--- /dev/null
+++ b/router/rerrors/400s.go
@@ -0,0 +1,16 @@
+package rerrors
+
+import "net/http"
+
+func MissingParameters(params []string) RouteError {
+	return NewRouteError(http.StatusBadRequest, "Missing parameters", map[string]any{
+		"missing_parameters": params,
+	})
+}
+
+func MethodNowAllowed(method string, allowedMethods []string) RouteError {
+	return NewRouteError(http.StatusMethodNotAllowed, "Method not allowed", map[string]any{
+		"method":          method,
+		"allowed_methods": allowedMethods,
+	})
+}
diff --git a/router/rerrors/500s.go b/router/rerrors/500s.go
new file mode 100644
index 0000000..36089ad
--- /dev/null
+++ b/router/rerrors/500s.go
@@ -0,0 +1,12 @@
+package rerrors
+
+import (
+	"errors"
+	"net/http"
+)
+
+func InternalError(errs ...error) RouteError {
+	return NewRouteError(http.StatusInternalServerError, "Internal server error", map[string]any{
+		"errors": errors.Join(errs...),
+	})
+}
diff --git a/router/rerrors/errors.go b/router/rerrors/errors.go
new file mode 100644
index 0000000..9a2d4c3
--- /dev/null
+++ b/router/rerrors/errors.go
@@ -0,0 +1,57 @@
+package rerrors
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+)
+
+type RouteError struct {
+	StatusCode int            `json:"status_code"`
+	Error      string         `json:"error"`
+	Info       map[string]any `json:"info"`
+}
+
+func NewRouteError(status int, error string, info ...map[string]any) RouteError {
+	rerr := RouteError{StatusCode: status, Error: error}
+	if len(info) > 0 {
+		rerr.Info = info[0]
+	} else {
+		rerr.Info = map[string]any{}
+	}
+	return rerr
+}
+
+func (rerr RouteError) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if rerr.StatusCode == 0 {
+		rerr.StatusCode = http.StatusNotImplemented
+	}
+
+	if rerr.Error == "" {
+		rerr.Error = "MISSING ERROR DESCRIPTION"
+	}
+
+	if rerr.Info == nil {
+		rerr.Info = map[string]any{}
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+
+	j, err := json.Marshal(rerr)
+	if err != nil {
+		j, _ := json.Marshal(RouteError{
+			StatusCode: http.StatusInternalServerError,
+			Error:      "Failed to marshal error message to JSON",
+			Info: map[string]any{
+				"source_value": fmt.Sprintf("%#v", rerr),
+				"error":        err.Error(),
+			},
+		})
+		w.Write(j)
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	w.Write(j)
+	w.WriteHeader(rerr.StatusCode)
+}