#!/usr/bin/env bash
# Builds the WebAssembly ("web") build of DESI Explorer with Odin
# (js_wasm32) + emscripten. Output: build/web/index.html (+ index.wasm,
# odin.js) at the repo root. Run via `make -C gui build-web`.
#
# Requires:
#   - `odin` on PATH with the js_wasm32 target
#   - emcc / emscripten active in PATH
# Optional:
#   - ODIN_ROOT (defaults to `odin root`)
#   - OUT_DIR   (defaults to <repo>/build/web)
set -euo pipefail

# Resolve the gui/ project root so this script works regardless of CWD.
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
GUI_DIR="$(cd "${SCRIPT_DIR}/.." && pwd)"
ROOT_DIR="$(cd "${GUI_DIR}/.." && pwd)"

OUT_DIR="${OUT_DIR:-${ROOT_DIR}/build/web}"
ODIN_ROOT="${ODIN_ROOT:-$(odin root)}"

mkdir -p "${GUI_DIR}/lib/local"
mkdir -p "$OUT_DIR"

# The Odin compiler emits a wasm object; raylib's C code is linked later by
# emcc. `-define:RAYLIB_WASM_LIB=env.o` stops the compiler from trying to
# link the raylib lib itself (emcc does that; it ends up in the final module).
odin build "${GUI_DIR}/src" \
  -target:js_wasm32 \
  -build-mode:obj \
  -define:RAYLIB_WASM_LIB=env.o \
  -o:speed \
  -collection:lib="${GUI_DIR}/lib/local" \
  -out:"${OUT_DIR}/game"

# Odin's JS runtime glue; the generated module imports functions from it.
cp "${ODIN_ROOT}/core/sys/wasm/js/odin.js" "${OUT_DIR}/odin.js"

# Link with emscripten against raylib's prebuilt web library. Flags mirror the
# known-good karl-zylinski/odin-raylib-web template.
emcc \
  -o "${OUT_DIR}/index.html" \
  "${OUT_DIR}/game.obj" \
  "${ODIN_ROOT}/vendor/raylib/wasm/libraylib.web.a" \
  --shell-file "${GUI_DIR}/www/index_template.html" \
  -sEXPORTED_RUNTIME_METHODS="['HEAPF32']" \
  -sUSE_GLFW=3 \
  -sWASM_BIGINT \
  -sWARN_ON_UNDEFINED_SYMBOLS=0 \
  -sASSERTIONS

rm -f "${OUT_DIR}/game.obj"

echo "Web build created in ${OUT_DIR}"