build: add auto_build.sh for modular compilation with optional clean

This script automates the build process based on CXXFLAGS-defined modules.
It also offers an option to clean previous builds before compiling.

Author: moisesPompilio

auto_build.sh

@@ -0,0 +1,130 @@
+#!/bin/bash
+
+if [ -z "$CXXFLAGS" ]; then
+    echo "Error: CXXFLAGS not defined. Example: CXXFLAGS=\"-DLDK -DLND\" ./auto_build.sh"
+    exit 1
+fi
+
+# Runs make clean to clean everything before starting
+echo "Cleaning previous builds..."
+make clean || { echo "Error: 'make clean' failed"; exit 1; }
+
+# Function to execute a command in a module's directory
+execute_in_module() {
+    local module_dir=$1
+    local command=$2
+
+    if [ -d "$module_dir" ]; then
+        echo "Executing in $module_dir: $command"
+        (cd "$module_dir" && eval "$command") || { echo "Error: Failed to execute in $module_dir"; exit 1; }
+    else
+        echo "Error: Directory $module_dir does not exist"
+        exit 1
+    fi
+}
+
+# Functions for each module
+bitcoin_core() {
+    execute_in_module "modules/bitcoin" "$1"
+}
+
+rust_bitcoin() {
+    execute_in_module "modules/rustbitcoin" "$1"
+}
+
+rust_miniscript() {
+    execute_in_module "modules/rustminiscript" "$1"
+}
+
+btcd() {
+    execute_in_module "modules/btcd" "$1"
+}
+
+embit() {
+    execute_in_module "modules/embit" "$1"
+}
+
+lnd() {
+    execute_in_module "modules/lnd" "$1"
+}
+
+ldk() {
+    execute_in_module "modules/ldk" "$1"
+}
+
+nlightning() {
+    execute_in_module "modules/nlightning" "$1"
+}
+
+# Define the list of modules
+modules="bitcoin_core rust_bitcoin rust_miniscript btcd embit lnd ldk nlightning"
+
+# Full clean: runs `make clean` in all module directories
+full_clean() {
+    echo "Performing full clean..."
+    for module in $modules; do
+        $module "make clean"
+    done
+}
+
+# Clean based on CXXFLAGS
+clean_selected_by_cxxflags() {
+    echo "Performing clean based on CXXFLAGS=$CXXFLAGS..."
+    for module in $modules; do
+        module_name=$(echo "$module" | tr '[:lower:]' '[:upper:]')
+        if echo "$CXXFLAGS" | grep -q "$module_name"; then
+            $module "make clean"
+        fi
+    done
+}
+
+# Selective clean based on CLEAN_BUILD flags
+select_clean() {
+    echo "Performing selective clean based on CLEAN_BUILD=$CLEAN_BUILD..."
+    for module in $modules; do
+        module_name=$(echo "$module" | tr '[:lower:]' '[:upper:]')
+        if echo "$CLEAN_BUILD" | grep -q "$module_name"; then
+            $module "make clean"
+        fi
+    done
+}
+
+# Determine which clean to perform
+if [ -n "$CLEAN_BUILD" ]; then
+    case "$CLEAN_BUILD" in
+        FULL)
+            full_clean
+            ;;
+        CLEAN)
+            clean_selected_by_cxxflags
+            ;;
+        *)
+            select_clean
+            ;;
+    esac
+else
+    echo "No CLEAN_BUILD option specified. Skipping clean step."
+fi
+
+# Builds modules based on flags
+echo "Compiling selected modules with CXXFLAGS=$CXXFLAGS..."
+
+for module in $modules; do
+    module_name=$(echo "$module" | tr '[:lower:]' '[:upper:]')
+    if echo "$CXXFLAGS" | grep -q "$module_name"; then
+        case "$module" in
+            rust_bitcoin|rust_miniscript|ldk)
+                $module "rustup default nightly && make cargo && make"
+                ;;
+            *)
+                $module "make"
+                ;;
+        esac
+    fi
+done
+
+# Returns to the root and performs the final build of the project
+echo "Compiling the main project in the root..."
+make || { echo "Error: Failed to compile the main project"; exit 1; }
+
+echo "Build completed successfully!"