#!/bin/sh
# Step: Extract original BIOS from both EEPROM chips
#
# Order rationale: read 4MB (top) chip first — smaller, faster,
# surfaces setup issues (clip alignment, voltage, ribbon) sooner.

# Probe the currently-clipped chip and resolve the flashrom chip name.
#   $1 = variable name to populate (e.g. "CHIP_4MB")
# Handles the "Multiple flash chip definitions match" case by prompting.
_resolve_chip() {
  _var="$1"

  eval _cur=\"\$$_var\"
  if [ -n "$_cur" ]; then
    info "Using previously-selected chip for this size: $_cur"
    return 0
  fi

  _log=$(mktemp)
  printf "  ${DIM}\$ sudo flashrom --programmer ch341a_spi${NC}\n"
  sudo flashrom --programmer ch341a_spi >"$_log" 2>&1
  _st=$?

  # Unambiguous success: one "Found ... chip \"NAME\"" line, exit 0.
  if [ $_st -eq 0 ]; then
    _chip=$(sed -nE 's/.*Found .* flash chip "([^"]+)".*/\1/p' "$_log" | head -1)
    if [ -n "$_chip" ]; then
      eval "$_var=\"\$_chip\""
      info "Detected chip: $_chip"
      rm -f "$_log"
      return 0
    fi
  fi

  # Ambiguous match: flashrom lists candidates but refuses to pick.
  if grep -q "Multiple flash chip definitions match" "$_log"; then
    _candidates=$(sed -nE 's/.*Found .* flash chip "([^"]+)".*/\1/p' "$_log")
    _count=$(printf '%s\n' "$_candidates" | wc -l | tr -d ' ')
    echo ""
    warn "Flashrom read the chip but multiple variants match the same silicon ID."
    info "This is normal for Winbond W25Q* parts. Pick one (the newest is safe):"
    echo ""
    _i=1
    for _c in $_candidates; do
      if [ "$_i" = "$_count" ]; then
        echo "  $_i) $_c   ${DIM}(default — newest)${NC}"
      else
        echo "  $_i) $_c"
      fi
      _i=$((_i+1))
    done
    echo ""

    _picked=""
    while [ -z "$_picked" ]; do
      printf "${CYAN}Choice [1-%s] (Enter = %s):${NC} " "$_count" "$_count"
      read -r _sel
      [ -z "$_sel" ] && _sel="$_count"
      case "$_sel" in
        ''|*[!0-9]*) echo "Enter a number."; continue ;;
      esac
      if [ "$_sel" -lt 1 ] || [ "$_sel" -gt "$_count" ]; then
        echo "Out of range."
        continue
      fi
      _picked=$(printf '%s\n' "$_candidates" | sed -n "${_sel}p")
    done
    eval "$_var=\"\$_picked\""
    info "Using chip definition: $_picked"
    rm -f "$_log"
    return 0
  fi

  # Real failure (no chip, clip bad, etc.) — show the log and fail.
  echo ""
  error "Chip probe failed. flashrom output:"
  sed 's/^/    /' "$_log"
  rm -f "$_log"
  return 1
}

# Read a chip with inline retry on failure.
#   $1 = output filename
#   $2 = human label
#   $3 = chip name (from _resolve_chip)
_read_with_retry() {
  _out="$1"
  _label="$2"
  _chip="$3"

  while true; do
    info "Reading $_label ..."
    if run_cmd "sudo flashrom --programmer ch341a_spi -c \"$_chip\" -r $_out"; then
      return 0
    fi

    echo ""
    warn "Read failed. Most common causes:"
    echo "    - Clip not seated flush on chip (try pressing down gently)"
    echo "    - Pin 1 misaligned (red wire must match chip's dot/notch)"
    echo "    - Laptop still has residual power (remove battery + CMOS)"
    echo "    - Cheap SOIC-8 clips can make intermittent contact"
    echo ""
    echo "  1) Re-seat clip and retry"
    echo "  2) Abort"
    echo ""
    printf "${CYAN}Choice [1-2]:${NC} "
    read -r _choice
    case "$_choice" in
      1) continue ;;
      *) return 1 ;;
    esac
  done
}

step_extract_bios() {
  section "Extract Original BIOS"

  info "The T440p has two EEPROM chips beside the SODIMM slots:"
  echo "  - 4MB (top)    — smaller SOIC-8, farther from CPU"
  echo "  - 8MB (bottom) — larger SOIC-8, closer to CPU (holds ME firmware)"
  echo ""
  info "Each chip is read twice so we can diff the results and catch flaky reads."
  echo ""

  cd "$WORK_DIR" || return 1

  # --- 4MB chip (do first: smaller = faster iteration on setup) ---
  echo ""
  show_image "eeprom_chip_4mb.webp" "Reference: 4MB (top) chip location on T440p"
  echo ""
  info "Clip the CH341A onto the ${BOLD}4MB (top)${NC} chip shown above."
  info "Align the red ribbon wire with the dot/notch on the chip (pin 1)."
  prompt_continue

  _resolve_chip CHIP_4MB || return 1
  _read_with_retry "4mb_backup1.bin" "4MB chip (read 1 of 2)" "$CHIP_4MB" || return 1
  _read_with_retry "4mb_backup2.bin" "4MB chip (read 2 of 2)" "$CHIP_4MB" || return 1
  success "4MB chip reads complete ($CHIP_4MB)."

  # --- 8MB chip ---
  echo ""
  show_image "eeprom_chip_8mb.webp" "Reference: 8MB (bottom) chip location on T440p"
  echo ""
  info "Now move the clip to the ${BOLD}8MB (bottom)${NC} chip shown above."
  info "Re-check pin 1 alignment before pressing down."
  prompt_continue

  _resolve_chip CHIP_8MB || return 1
  _read_with_retry "8mb_backup1.bin" "8MB chip (read 1 of 2)" "$CHIP_8MB" || return 1
  _read_with_retry "8mb_backup2.bin" "8MB chip (read 2 of 2)" "$CHIP_8MB" || return 1
  success "8MB chip reads complete ($CHIP_8MB)."
}