From ada63198a1e6fbe468f6d9174bf6e423c1c122f8 Mon Sep 17 00:00:00 2001
From: Abhishek Shroff <shroff@kudosoft.net>
Date: Sat, 3 Aug 2024 08:07:49 +0530
Subject: [PATCH] WIP: Permissions

---
 server/internal/app/resources.go              | 24 +++++++++++
 server/internal/command/command.go            |  4 +-
 .../migrations/data/006_permissions.sql       | 10 +++++
 server/internal/sql/models.go                 |  6 +++
 server/internal/sql/permissions.sql.go        | 42 +++++++++++++++++++
 server/sql/queries/permissions.sql            | 10 +++++
 server/sql/queries/resources.sql              |  2 +-
 7 files changed, 96 insertions(+), 2 deletions(-)
 create mode 100644 server/internal/app/resources.go
 create mode 100644 server/internal/migrations/data/006_permissions.sql
 create mode 100644 server/internal/sql/permissions.sql.go
 create mode 100644 server/sql/queries/permissions.sql

diff --git a/server/internal/app/resources.go b/server/internal/app/resources.go
new file mode 100644
index 00000000..a4f5ffda
--- /dev/null
+++ b/server/internal/app/resources.go
@@ -0,0 +1,24 @@
+package app
+
+import (
+	"context"
+	"errors"
+
+	"github.com/google/uuid"
+	"github.com/jackc/pgx/v5"
+	"github.com/shroff/phylum/server/internal/sql"
+)
+
+var ErrResourceNotFound = errors.New("resource not found")
+
+func (a *App) LocateResource(id uuid.UUID, username string) (uuid.UUID, int, error) {
+	result, err := a.Db.Queries().PermissionsForResource(context.Background(), sql.PermissionsForResourceParams{ResourceID: id, Username: username})
+	if err == pgx.ErrNoRows {
+		err = ErrResourceNotFound
+	}
+	if err != nil {
+		return uuid.UUID{}, 0, err
+	}
+
+	return result.ID, int(result.Permission.Int32), nil
+}
diff --git a/server/internal/command/command.go b/server/internal/command/command.go
index eae4b2cd..892cad0d 100644
--- a/server/internal/command/command.go
+++ b/server/internal/command/command.go
@@ -56,7 +56,9 @@ func SetupCommand() {
 
 	defer func() {
 		logrus.Info("Shutting Down App")
-		app.Default.Cleanup()
+		if app.Default != nil {
+			app.Default.Cleanup()
+		}
 	}()
 
 	rootCmd.AddCommand([]*cobra.Command{
diff --git a/server/internal/migrations/data/006_permissions.sql b/server/internal/migrations/data/006_permissions.sql
new file mode 100644
index 00000000..1670e3a2
--- /dev/null
+++ b/server/internal/migrations/data/006_permissions.sql
@@ -0,0 +1,10 @@
+CREATE TABLE permissions(
+    resource_id  uuid NOT NULL,
+    username     TEXT NOT NULL,
+    permission   INT NOT NULL,
+    PRIMARY KEY(resource_id, username)
+);
+
+---- create above / drop below ----
+
+DROP TABLE permissions;
\ No newline at end of file
diff --git a/server/internal/sql/models.go b/server/internal/sql/models.go
index 178dcacd..27266e9c 100644
--- a/server/internal/sql/models.go
+++ b/server/internal/sql/models.go
@@ -16,6 +16,12 @@ type AccessToken struct {
 	Username string
 }
 
+type Permission struct {
+	ResourceID uuid.UUID
+	Username   string
+	Permission int32
+}
+
 type Resource struct {
 	ID       uuid.UUID
 	Parent   *uuid.UUID
diff --git a/server/internal/sql/permissions.sql.go b/server/internal/sql/permissions.sql.go
new file mode 100644
index 00000000..a94ea754
--- /dev/null
+++ b/server/internal/sql/permissions.sql.go
@@ -0,0 +1,42 @@
+// Code generated by sqlc. DO NOT EDIT.
+// versions:
+//   sqlc v1.26.0
+// source: permissions.sql
+
+package sql
+
+import (
+	"context"
+
+	"github.com/google/uuid"
+	"github.com/jackc/pgx/v5/pgtype"
+)
+
+const permissionsForResource = `-- name: PermissionsForResource :one
+WITH RECURSIVE nodes(id, parent, permission) AS (
+    SELECT r.id, r.parent, p.permission
+    FROM resources r LEFT JOIN permissions p on r.id = p.resource_id WHERE r.id = $1::uuid AND p.username = $2::text
+  UNION ALL
+    SELECT r.id, r.parent, CASE WHEN (n.permission IS NULL OR p.permission > n.permission) THEN p.permission ELSE n.permission END
+    FROM resources r JOIN nodes n ON r.id = n.parent LEFT JOIN permissions p ON r.id = p.resource_id AND p.username = $2::text
+)
+SELECT id, parent, permission FROM nodes WHERE parent IS NULL
+`
+
+type PermissionsForResourceParams struct {
+	ResourceID uuid.UUID
+	Username   string
+}
+
+type PermissionsForResourceRow struct {
+	ID         uuid.UUID
+	Parent     *uuid.UUID
+	Permission pgtype.Int4
+}
+
+func (q *Queries) PermissionsForResource(ctx context.Context, arg PermissionsForResourceParams) (PermissionsForResourceRow, error) {
+	row := q.db.QueryRow(ctx, permissionsForResource, arg.ResourceID, arg.Username)
+	var i PermissionsForResourceRow
+	err := row.Scan(&i.ID, &i.Parent, &i.Permission)
+	return i, err
+}
diff --git a/server/sql/queries/permissions.sql b/server/sql/queries/permissions.sql
new file mode 100644
index 00000000..2b89c0b4
--- /dev/null
+++ b/server/sql/queries/permissions.sql
@@ -0,0 +1,10 @@
+
+-- name: PermissionsForResource :one
+WITH RECURSIVE nodes(id, parent, permission) AS (
+    SELECT r.id, r.parent, p.permission
+    FROM resources r LEFT JOIN permissions p on r.id = p.resource_id WHERE r.id = @resource_id::uuid AND p.username = @username::text
+  UNION ALL
+    SELECT r.id, r.parent, CASE WHEN (n.permission IS NULL OR p.permission > n.permission) THEN p.permission ELSE n.permission END
+    FROM resources r JOIN nodes n ON r.id = n.parent LEFT JOIN permissions p ON r.id = p.resource_id AND p.username = @username::text
+)
+SELECT * FROM nodes WHERE parent IS NULL;
\ No newline at end of file
diff --git a/server/sql/queries/resources.sql b/server/sql/queries/resources.sql
index 9157e3f3..f7fb50c8 100644
--- a/server/sql/queries/resources.sql
+++ b/server/sql/queries/resources.sql
@@ -80,4 +80,4 @@ WITH RECURSIVE nodes(id, parent) AS (
 )
 DELETE FROM resources
 WHERE id in (SELECT id FROM nodes)
-RETURNING id, dir;
\ No newline at end of file
+RETURNING id, dir;