#!/usr/bin/env bash
# build_wasm_cpp_app — compila app cpp/apps/<name> a WASM via emscripten.
#
# Uso:
#   build_wasm_cpp_app.sh <app_name> [--no-budget-check]
#
# Salida: build/wasm/<name>/<name>.{html,js,wasm}
#         + <name>.wasm.gz (gzip -9) y <name>.wasm.br (brotli -11 si esta).
#
# Requiere: emsdk activo en el shell (source emsdk/emsdk_env.sh) o que
# exista emsdk/ en la raiz del repo y se autoactive.

set -euo pipefail

APP="${1:?Uso: $0 <app_name> [--no-budget-check]}"
SHIFT_FLAG="${2:-}"

REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")"/../../.. && pwd)"
SRC_DIR="$REPO_ROOT/cpp/apps/$APP"
BUILD_DIR="$REPO_ROOT/build/wasm/$APP"

if [ ! -d "$SRC_DIR" ]; then
    echo "ERROR: $SRC_DIR no existe" >&2
    exit 1
fi

# Activate emsdk if not already in PATH.
if ! command -v emcc >/dev/null 2>&1; then
    if [ -f "$REPO_ROOT/emsdk/emsdk_env.sh" ]; then
        # shellcheck disable=SC1091
        source "$REPO_ROOT/emsdk/emsdk_env.sh" >/dev/null 2>&1
    fi
fi
if ! command -v emcc >/dev/null 2>&1; then
    echo "ERROR: emcc no encontrado. Instala emsdk:" >&2
    echo "  git clone https://github.com/emscripten-core/emsdk.git" >&2
    echo "  cd emsdk && ./emsdk install latest && ./emsdk activate latest" >&2
    echo "  source ./emsdk_env.sh" >&2
    exit 1
fi

echo "── emcc: $(emcc --version | head -n1)"
echo "── source: $SRC_DIR"
echo "── build:  $BUILD_DIR"

mkdir -p "$BUILD_DIR"
# Build the app directly (NOT the full cpp/ tree). Each app's CMakeLists.txt
# is expected to be self-sufficient as top-level (issue 0072a pattern).
emcmake cmake -S "$SRC_DIR" -B "$BUILD_DIR" -DCMAKE_BUILD_TYPE=MinSizeRel
cmake --build "$BUILD_DIR" --target "$APP" -j

WASM_DIR=$(find "$BUILD_DIR" -name "$APP.wasm" -printf '%h\n' -quit 2>/dev/null || true)
if [ -z "$WASM_DIR" ]; then
    echo "ERROR: no se encontro $APP.wasm en $BUILD_DIR" >&2
    exit 2
fi

cd "$WASM_DIR"
gzip -9 -k -f "$APP.wasm"
if command -v brotli >/dev/null 2>&1; then
    brotli -q 11 -k -f "$APP.wasm"
fi

echo
echo "── Sizes (in $WASM_DIR) ──"
for f in "$APP".html "$APP".js "$APP".wasm "$APP".wasm.gz "$APP".wasm.br; do
    [ -f "$f" ] && printf "%-32s %10d bytes\n" "$f" "$(stat -c%s "$f")"
done

# Budget check (1.5 MB gzip soft, 2 MB hard)
if [ "$SHIFT_FLAG" != "--no-budget-check" ]; then
    SIZE_GZ=$(stat -c%s "$APP.wasm.gz")
    HARD=$((2 * 1024 * 1024))
    SOFT=$((1572864))  # 1.5 MB
    if [ "$SIZE_GZ" -gt "$HARD" ]; then
        echo "❌ $APP.wasm.gz = $SIZE_GZ bytes > $HARD (2 MB hard limit)" >&2
        exit 3
    elif [ "$SIZE_GZ" -gt "$SOFT" ]; then
        echo "⚠ $APP.wasm.gz = $SIZE_GZ bytes > $SOFT (1.5 MB soft limit)"
    else
        echo "✓ $APP.wasm.gz = $SIZE_GZ bytes within soft limit (1.5 MB)"
    fi
fi