From 3878ee0ad0a710f47b1ca9d5fc84983d3ef233d1 Mon Sep 17 00:00:00 2001
From: coffeepots <ryan@status.im>
Date: Tue, 22 May 2018 20:48:12 +0100
Subject: [PATCH] Implemented signature parsing to create client rpc procs
 based on params

---
 eth-rpc/client/clientdispatch.nim | 119 +++++++++++++++++++++++++++---
 1 file changed, 108 insertions(+), 11 deletions(-)

diff --git a/eth-rpc/client/clientdispatch.nim b/eth-rpc/client/clientdispatch.nim
index 36dacfa..59888ef 100644
--- a/eth-rpc/client/clientdispatch.nim
+++ b/eth-rpc/client/clientdispatch.nim
@@ -1,4 +1,5 @@
 import asyncnet, asyncdispatch, tables, json, oids, ethcalls, macros
+import ../ ethtypes, stint, ../ jsonconverters
 
 type
   RpcClient* = ref object
@@ -88,17 +89,113 @@ proc connect*(self: RpcClient, address: string, port: Port) {.async.} =
   self.port = port
   asyncCheck processData(self)
 
-macro generateCalls: untyped =
-  ## Generate templates for client calls so that:
-  ##   client.call("web3_clientVersion", params)
-  ## can be written as:
-  ##   client.web3_clientVersion(params)
+import jsonmarshal
+
+proc createRpcFromSig*(rpcDecl: NimNode): NimNode =
+  let procNameState = rpcDecl[0]
+  var
+    parameters = rpcDecl.findChild(it.kind == nnkFormalParams).copy
+    path: NimNode
+    pathStr: string
+
+  # get proc signature's name. This becomes the path we send to the server
+  if procNameState.kind == nnkPostFix:
+    path = rpcDecl[0][1]
+  else:
+    path = rpcDecl[0]
+  pathStr = $path   
+
+  if parameters.isNil or parameters.kind == nnkEmpty:
+    parameters = newNimNode(nnkFormalParams)
+
+  # if no return parameters specified (parameters[0])
+  if parameters.len == 0: parameters.add(newEmptyNode())
+  # insert rpc client as first parameter
+  let
+    clientParam =
+      nnkIdentDefs.newTree(
+        ident"client",
+        ident"RpcClient",
+        newEmptyNode()
+      )
+  parameters.insert(1, clientParam)
+
+  # For each input parameter we need to
+  # take the Nim type and translate to json with `%`.
+  # For return types, we need to take the json and
+  # convert it to the Nim type.
+  var
+    callBody = newStmtList()
+    returnType: NimNode
+  let jsonParamIdent = genSym(nskVar, "jsonParam")
+  callBody.add(quote do:
+    var `jsonParamIdent` = newJArray()
+  )
+  if parameters.len > 2:
+    # skip return type and the inserted rpc client parameter
+    # add the rest to json node via `%`
+    for i in 2 ..< parameters.len:
+      let curParam = parameters[i][0]
+      if curParam.kind != nnkEmpty:
+        callBody.add(quote do:
+          `jsonParamIdent`.add(%`curParam`)
+        )
+  if parameters[0].kind != nnkEmpty:
+    returnType = parameters[0]
+  else:
+    returnType = ident"JsonNode"
+  
+  # convert return type to Future
+  parameters[0] = nnkBracketExpr.newTree(ident"Future", returnType)
+
+  # client call to server using json params
+  var updatedParams = newSeq[NimNode]()
+  # convert parameter tree to seq
+  for p in parameters: updatedParams.add(p) 
+  # create new proc
+  result = newProc(path, updatedParams, callBody)
+  # convert this proc to async
+  result.addPragma ident"async"
+  # export this proc
+  result[0] = nnkPostFix.newTree(ident"*", ident(pathStr))
+  # add rpc call to proc body
+  var callResult = genSym(nskVar, "res")
+
+  callBody.add(quote do:
+    let res = await client.call(`pathStr`, `jsonParamIdent`)
+    if res.error: raise newException(ValueError, $res.result)
+    var `callResult` = res.result
+  )
+  let
+    procRes = ident"result"
+  # now we need to extract the response and build it into the expected type
+  if returnType != ident"JsonNode":
+    let setup = setupParamFromJson(procRes, returnType, callResult)
+    callBody.add(quote do: `setup`)
+  else:
+    callBody.add(quote do:
+      `procRes` = `callResult`
+      )
+  when defined(nimDumpRpcs):
+    echo pathStr, ":\n", result.repr
+
+from os import getCurrentDir, DirSep
+from strutils import rsplit
+
+macro processRpcSigs(): untyped =
   result = newStmtList()
-  for callName in ETHEREUM_RPC_CALLS:
-    let nameLit = ident(callName)
-    result.add(quote do:
-      template `nameLit`*(client: RpcClient, params: JsonNode): Future[Response] = client.call(`callName`, params)  # TODO: Back to template
-    )
+  const
+    codePath = currentSourcePath.rsplit(DirSep, 1)[0] & DirSep & "ethcallsigs.nim"
+    code = staticRead(codePath)
+
+  let parsedCode = parseStmt(code)
+  var line = 0
+  while line < parsedCode.len:
+    if parsedCode[line].kind == nnkProcDef: break
+    line += 1
+  for curLine in line ..< parsedCode.len:
+    var procDef = createRpcFromSig(parsedCode[curLine])
+    result.add(procDef)
 
 # generate all client ethereum rpc calls
-generateCalls()
+processRpcSigs()