#!/bin/bash
# build_signer.sh — reproducible build + optional flash for the Teensy 4.1 n_signer.
#
# Usage:
#   ./firmware/teensy41/build_signer.sh           # compile only
#   ./firmware/teensy41/build_signer.sh --flash    # compile + upload
#   ./firmware/teensy41/build_signer.sh --test     # compile + upload + run test suite
#
# This script handles:
#   - Copying lv_conf.h to the Arduino libraries directory (where LVGL's
#     lv_conf_internal.h searches for it via ../../lv_conf.h).
#   - Passing the custom linker script (imxrt1062_t41_flashmem.ld) that routes
#     crypto code to FLASH instead of ITCM, freeing stack space.
#   - Printing the memory usage report.
#   - Optionally uploading to the first discovered Teensy port.
#   - Optionally running the hardware test suite.

set -e

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
SIGNER_DIR="$SCRIPT_DIR/signer"
FQBN="teensy:avr:teensy41"
LV_CONF_SRC="$SIGNER_DIR/lv_conf.h"
LV_CONF_DST="$HOME/Arduino/libraries/lv_conf.h"
LINKER_SCRIPT="$SIGNER_DIR/imxrt1062_t41_flashmem.ld"

# --- Step 1: Copy lv_conf.h to the Arduino libraries directory ---
if [ -f "$LV_CONF_SRC" ]; then
  mkdir -p "$(dirname "$LV_CONF_DST")"
  cp "$LV_CONF_SRC" "$LV_CONF_DST"
  echo "[build] Copied lv_conf.h to $LV_CONF_DST"
else
  echo "[build] WARNING: $LV_CONF_SRC not found — LVGL may use default config."
fi

# --- Step 2: Compile with the custom linker script ---
echo "[build] Compiling..."
LINKER_FLAG="-Wl,--gc-sections,--relax,--no-warn-rwx-segments -T${LINKER_SCRIPT}"

if [ -f "$LINKER_SCRIPT" ]; then
  arduino-cli compile \
    --fqbn "$FQBN" \
    --build-property "build.flags.ld=${LINKER_FLAG}" \
    "$SIGNER_DIR" || true  # size-determination step may error with custom .ld
else
  echo "[build] WARNING: Linker script not found at $LINKER_SCRIPT — using default."
  arduino-cli compile --fqbn "$FQBN" "$SIGNER_DIR"
fi

# --- Step 2b: FlexRAM stack gauge ---
# arduino-cli's "Error while determining sketch size" with a custom linker
# script is non-fatal (the ELF is produced), but it means we lose the built-in
# memory report. Run our own gauge against the ELF to catch DTCM stack
# overflows that the linker cannot detect (the ITCM/DTCM split is computed at
# boot, not link time).
ELF_FILE=$(find "$HOME/.cache/arduino/sketches" -name "signer.ino.elf" -newer "$LINKER_SCRIPT" 2>/dev/null | head -1)
if [ -z "$ELF_FILE" ]; then
  ELF_FILE=$(find "$HOME/.cache/arduino/sketches" -name "signer.ino.elf" 2>/dev/null | head -1)
fi
if [ -n "$ELF_FILE" ] && [ -f "$ELF_FILE" ]; then
  echo "[build] Running FlexRAM stack gauge..."
  bash "$SCRIPT_DIR/check_stack.sh" "$ELF_FILE" 16384 || {
    echo "[build] ❌ Stack gauge FAILED — refusing to flash. See check_stack.sh output above."
    exit 1
  }
else
  echo "[build] WARNING: could not find signer.ino.elf for stack gauge — skipping."
fi

echo "[build] Compilation successful."

# --- Step 3: Find the Teensy port ---
find_teensy_port() {
  arduino-cli board list 2>/dev/null | grep 'teensy   Teensy Ports' | awk '{print $1}' | head -1
}

# --- Step 4: Flash (if --flash or --test) ---
if [ "$1" = "--flash" ] || [ "$1" = "--test" ]; then
  PORT=$(find_teensy_port)
  if [ -z "$PORT" ]; then
    echo "[flash] No Teensy found. Press the PROGRAM button on the Teensy."
    exit 1
  fi
  echo "[flash] Uploading to $PORT..."
  arduino-cli upload -p "$PORT" --fqbn "$FQBN" "$SIGNER_DIR"
  echo "[flash] Upload complete."
fi

# --- Step 5: Run test suite (if --test) ---
if [ "$1" = "--test" ]; then
  echo "[test] Waiting for device to boot..."
  sleep 4
  PORT_DEV=$(arduino-cli board list 2>/dev/null | grep 'ttyACM' | awk '{print $1}' | head -1)
  if [ -z "$PORT_DEV" ]; then
    PORT_DEV="/dev/ttyACM0"
  fi
  echo "[test] Running test suite on $PORT_DEV..."
  python3 "$SCRIPT_DIR/test_signer.py" --port "$PORT_DEV" || true
fi