feat(calldata): implement decodeTuple function

Author: AryanGodara

src/utils/calldata/calldataDecoder.ts

@@ -6,6 +6,7 @@ import {
   ByteArray,
   CairoEnum,
   ParsedStruct,
+  StructAbi,
   Tupled,
 } from '../../types';
 import { CairoUint256 } from '../cairoDataTypes/uint256';
@@ -24,6 +25,7 @@ import {
 } from './cairo';
 import {
   CairoCustomEnum,
+  CairoEnumRaw,
   CairoOption,
   CairoOptionVariant,
   CairoResult,
@@ -32,6 +34,7 @@ import {
 import extractTupleMemberTypes from './tuple';
 
 import { decodeShortString } from '../shortString';
+import { byteArray } from '.';
 
 /**
  * Parse base types
@@ -76,3 +79,138 @@ function decodeBaseType(type: string, calldata: string | string[]): BigNumberish
       return BigInt(calldata);
   }
 }
+
+/**
+ * Decode a tuple from calldata.
+ * @param calldata The calldata array.
+ * @param typeStr The type string representing the tuple structure.
+ * @param structs The ABI structs.
+ * @param enums The ABI enums.
+ * @returns An array of decoded tuple elements.
+ */
+function decodeTuple(calldata: string[], typeStr: string, structs: AbiStructs, enums: AbiEnums) {
+  // Parse typeStr to understand the tuple structure, e.g., "('felt', 'struct', 'enum')"
+  const types: string[] = extractTupleMemberTypes(typeStr).map((type: string | object) => String(type));
+  
+  // Assuming we now have an array of types, ['felt', 'YourStructName', 'YourEnumName'], etc.
+  const decodedElements = [];
+  let calldataIndex = 0;
+
+  for (const type of types) {
+    switch (true) {
+      case isTypeStruct(type, structs):
+        let structRes = decodeStruct(calldata.slice(calldataIndex, calldataIndex + structs[type].size), type, structs, enums);
+        decodedElements.push(structRes);
+        calldataIndex += structs[type].size; // Assuming size is defined for structs.
+        break;
+      case isTypeEnum(type, enums):
+        // Determine the expected calldata consumption for the current enum.
+        const expectedCalldataLength = getExpectedCalldataLengthForEnum(calldata[calldataIndex], type, enums);
+        const enumSlice = calldata.slice(calldataIndex, calldataIndex + expectedCalldataLength);
+        const enumRes = decodeEnum(enumSlice, type, enums);
+        decodedElements.push(enumRes);
+        calldataIndex += expectedCalldataLength; // Move past the consumed calldata.
+        break;
+      case isTypeArray(type):
+        const arrayType = getArrayType(type);
+        const arrayRes = decodeCalldataValue([calldata[calldataIndex]], arrayType, structs, enums);
+        decodedElements.push(arrayRes);
+        calldataIndex += 1;
+        break;
+      default:
+        const result = decodeBaseType(type, calldata[calldataIndex]);
+        decodedElements.push(result);
+        calldataIndex += 1;
+    }
+  }
+
+  return decodedElements;
+}
+
+function decodeByteArray(calldata: string[]): ByteArray {
+  // Implementation here...
+  return byteArrayFromString(calldata.join(''));
+}
+
+function decodeCalldataValue(calldata: string | string[], type: string, structs: AbiStructs, enums: AbiEnums): any {
+  // Implementation here...
+}
+
+function decodeCalldataField(calldataIterator: Iterator<string>, input: AbiEntry, structs: AbiStructs, enums: AbiEnums): any {
+  // Implementation here...
+}
+
+function decodeStruct(calldataSegment: string[], structName: string, structs: AbiStructs, enums: AbiEnums): ParsedStruct {
+  const structAbi: StructAbi = structs[structName];
+  if (!structAbi) {
+    throw new Error(`Struct with name ${structName} not found.`);
+  }
+
+  let index = 0;
+  const result: ParsedStruct = {};
+
+  for (const field of structAbi.members) {
+    const fieldType = field.type;
+    const fieldCalldata = calldataSegment.slice(index, index + 1); // This is simplified; complex types might span multiple elements.
+    result[field.name] = decodeCalldataValue(fieldCalldata[0], fieldType, structs, enums);
+    index++;
+  }
+
+  return result;
+}
+
+function decodeEnum(calldataValues: string[], enumName: string, enums: AbiEnums): CairoEnum {
+  const enumDefinition = enums[enumName];
+  if (!enumDefinition) {
+    throw new Error(`Enum with name ${enumName} not found.`);
+  }
+
+  const variantIndex = parseInt(calldataValues[0], 10);
+  if (variantIndex < 0 || variantIndex >= enumDefinition.variants.length) {
+    throw new Error(`Variant index ${variantIndex} out of range for enum ${enumName}.`);
+  }
+
+  const variant = enumDefinition.variants[variantIndex];
+
+  // Determine the enum type and decode accordingly
+  switch (enumName) {
+    case "CairoOption":
+      switch (variant.name) {
+        case "None":
+          return new CairoOption(CairoOptionVariant.None);
+        default: // "Some"
+          const someValue = calldataValues[1]; // Placeholder for actual decoding logic.
+          // The decoding of someValue needs to be based on the expected data type.
+          return new CairoOption(CairoOptionVariant.Some, someValue); // Assuming someValue decoding logic is implemented elsewhere.
+      }
+    case "CairoResult":
+      const resultValue = calldataValues[1]; // Placeholder for actual decoding logic.
+      
+      switch (variant.name) {
+        case "Ok":
+          return new CairoResult(CairoResultVariant.Ok , resultValue); // Needs proper decoding based on expected type.
+        default: // "Err"
+          return new CairoResult(CairoResultVariant.Err , resultValue); // Needs proper decoding based on expected type.
+      }
+
+    default: // Handling CairoCustomEnum or simple enum types without associated data.
+      return new CairoCustomEnum({ activeVariant: variant.name, variant: variant.name });
+  }
+}
+
+function getExpectedCalldataLengthForEnum(variantIndexCalldata: string, enumName: string, enums: AbiEnums): number {
+  const enumDefinition = enums[enumName];
+  if (!enumDefinition) throw new Error(`Enum with name ${enumName} not found.`);
+
+  const variantIndex = parseInt(variantIndexCalldata, 10);
+  const variant = enumDefinition.variants[variantIndex];
+
+  switch (enumName) {
+    case "CairoOption":
+      return variant.name === "None" ? 1 : 2; // "None" requires only the index, "Some" requires additional data.
+    case "CairoResult":
+      return 2; // Both "Ok" and "Err" require additional data.
+    default:
+      return 1; // Assuming other enums don't have associated data by default.
+  }
+}