From cfa782ec535d0d2c2488a4ffa7c9fc7688b0273d Mon Sep 17 00:00:00 2001
From: Sean Tyler Myers <seamyers@amazon.com>
Date: Thu, 9 Feb 2023 15:28:00 -0800
Subject: [PATCH] Add Fn::Cidr support

---
 README.md                                 |  6 +--
 src/ir/resources.rs                       | 18 ++++++++
 src/parser/resource.rs                    | 50 +++++++++++++++++++++++
 src/synthesizer/typescript_synthesizer.rs |  8 ++++
 4 files changed, 78 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index 6a779573..60e4675c 100644
--- a/README.md
+++ b/README.md
@@ -34,14 +34,12 @@ cargo build --release
 - [x] Fn::GetAZs support
 - [x] Adding depends-on, and ordering based on it too.
 - [x] Deletion policy
- 
+- [x] Fn::Cidr support 
+
 ## Remaining
 
 There are known unsupported features. Working on them in priority order:
 
-
-
-- [ ] Fn::Cidr support
 - [ ] Create policy
 - [ ] ssm metadata references
 - [ ] secretsmanager references
diff --git a/src/ir/resources.rs b/src/ir/resources.rs
index 1afbbb1d..6713bbd3 100644
--- a/src/ir/resources.rs
+++ b/src/ir/resources.rs
@@ -35,6 +35,7 @@ pub enum ResourceIr {
     ImportValue(Box<ResourceIr>),
     GetAZs(Box<ResourceIr>),
     Select(i64, Box<ResourceIr>),
+    Cidr(Box<ResourceIr>, Box<ResourceIr>, Box<ResourceIr>),
 }
 
 /// ResourceTranslationInputs is a place to store all the intermediate recursion
@@ -224,6 +225,11 @@ fn find_dependencies(
         ResourceIr::GetAZs(x) => {
             find_dependencies(resource_name, x.deref(), topo);
         }
+        ResourceIr::Cidr(x, y, z) => {
+            find_dependencies(resource_name, x.deref(), topo);
+            find_dependencies(resource_name, y.deref(), topo);
+            find_dependencies(resource_name, z.deref(), topo);
+        }
     }
 }
 
@@ -447,6 +453,18 @@ pub fn translate_resource(
             let ir = translate_resource(x, resource_translator)?;
             Ok(ResourceIr::GetAZs(Box::new(ir)))
         }
+        ResourceValue::Cidr(ip_block, count, cidr_bits) => {
+            let mut rt = resource_translator.clone();
+            rt.complexity = Structure::Simple(CfnType::String);
+            let ip_block_str = translate_resource(ip_block, &rt)?;
+            let count_str = translate_resource(count, &rt)?;
+            let cidr_bits_str = translate_resource(cidr_bits, &rt)?;
+            Ok(ResourceIr::Cidr(
+                Box::new(ip_block_str),
+                Box::new(count_str),
+                Box::new(cidr_bits_str),
+            ))
+        }
     }
 }
 
diff --git a/src/parser/resource.rs b/src/parser/resource.rs
index d139f913..194061b7 100644
--- a/src/parser/resource.rs
+++ b/src/parser/resource.rs
@@ -27,6 +27,7 @@ pub enum ResourceValue {
     Base64(Box<ResourceValue>),
     ImportValue(Box<ResourceValue>),
     Select(Box<ResourceValue>, Box<ResourceValue>),
+    Cidr(Box<ResourceValue>, Box<ResourceValue>, Box<ResourceValue>),
 }
 
 impl ResourceValue {}
@@ -420,6 +421,55 @@ pub fn build_resources_recursively(
 
                     ResourceValue::Join(v)
                 }
+                "Fn::Cidr" => {
+                    let v = match resource_object.as_array() {
+                        None => {
+                            return Err(TransmuteError {
+                                details: format!(
+                                    "Fn::Cidr is supposed to be an array entry {name}"
+                                ),
+                            })
+                        }
+                        Some(x) => x,
+                    };
+
+                    let first_obj = match v.get(0) {
+                        None => {
+                            return Err(TransmuteError {
+                                details: format!(
+                                    "Fn::Cidr is supposed to have 3 values in array, has 0 {name}"
+                                ),
+                            })
+                        }
+                        Some(x) => build_resources_recursively(name, x),
+                    }?;
+                    let second_obj = match v.get(1) {
+                        None => {
+                            return Err(TransmuteError {
+                                details: format!(
+                                    "Fn::Cidr is supposed to have 3 values in array, has 1 {name}"
+                                ),
+                            })
+                        }
+                        Some(x) => build_resources_recursively(name, x),
+                    }?;
+                    let third_obj = match v.get(2) {
+                        None => {
+                            return Err(TransmuteError {
+                                details: format!(
+                                    "Fn::Cidr is supposed to have 3 values in array, has 2 {name}"
+                                ),
+                            })
+                        }
+                        Some(x) => build_resources_recursively(name, x),
+                    }?;
+
+                    ResourceValue::Cidr(
+                        Box::new(first_obj),
+                        Box::new(second_obj),
+                        Box::new(third_obj),
+                    )
+                }
                 "Ref" => {
                     let ref_name = match resource_object.as_str() {
                         None => {
diff --git a/src/synthesizer/typescript_synthesizer.rs b/src/synthesizer/typescript_synthesizer.rs
index 171e5eb0..9a8436e0 100644
--- a/src/synthesizer/typescript_synthesizer.rs
+++ b/src/synthesizer/typescript_synthesizer.rs
@@ -388,6 +388,14 @@ pub fn to_string_ir(resource_value: &ResourceIr) -> Option<String> {
             let str = to_string_ir(obj.as_ref()).unwrap();
             Option::Some(format!("{}[{}]", str, *index))
         }
+        ResourceIr::Cidr(ip_block, count, cidr_bits) => {
+            let ip_block_str = to_string_ir(ip_block.as_ref()).unwrap();
+            let count_str = to_string_ir(count.as_ref()).unwrap();
+            let cidr_bits_str = to_string_ir(cidr_bits.as_ref()).unwrap();
+            Option::Some(format!(
+                "cdk.Fn.cidr({ip_block_str}, {count_str}, {cidr_bits_str})"
+            ))
+        }
     }
 }