#!/bin/bash
# Existing macOS Recovery/launchd runtime hook; never installs or erases anything.
set -u
PATH="/usr/bin:/bin:/usr/sbin:/sbin"
export PATH
PROOF_TOKEN="@@PROOF_TOKEN@@"
STATE_DIR="/Volumes/installstate"
PROOF_LOG="$STATE_DIR/proof.log"
RESULT="$STATE_DIR/result.json"
EXPECTED_BYTES=68719476736
MAX_LOG_BYTES=4194304
MAX_OUTPUT_BYTES=524288
TIMER_FIFO="/tmp/native-diagnostic-$PROOF_TOKEN-$$.fifo"
PENDING_OUTPUTS=()
ACTIVE_COMMAND=""
ACTIVE_TIMER=""
os_version=""
architecture=""
uid=-1
system_exit=-1
arbitration_exit=-1
recovery_exit=-1
disk_list_exit=-1
selected_disk=""
disk_bytes=0

count=0
while [ ! -d "$STATE_DIR" ] && (( count < 120 )); do
  /sbin/mount_9p installstate >/dev/null 2>&1 || :
  count=$((count + 1))
  sleep 1
done
[ -d "$STATE_DIR" ] || exit 1
: > "$PROOF_LOG" || exit 1
exec 3>> "$PROOF_LOG" || exit 1
rm -f "$RESULT" "$RESULT.tmp"
printf '[proof-token] %s\n' "$PROOF_TOKEN" >&3

finish() {
  local success="$1" reason="$2"
  flush_outputs || { success=false; reason=diagnostic_log_budget_exceeded; }
  printf '[proof-result] %s: %s\n' "$success" "$reason" >&3
  printf '{"token":"%s","success":%s,"reason":"%s","osVersion":"%s","architecture":"%s","uid":%s,"systemExit":%s,"diskArbitrationExit":%s,"recoveryExit":%s,"diskListExit":%s,"disk":"%s","diskBytes":%s,"readOnly":false}\n' \
    "$PROOF_TOKEN" "$success" "$reason" "$os_version" "$architecture" "$uid" \
    "$system_exit" "$arbitration_exit" "$recovery_exit" "$disk_list_exit" \
    "$selected_disk" "$disk_bytes" > "$RESULT.tmp"
  /bin/mv -f "$RESULT.tmp" "$RESULT" || exit 1
  exec 9>&-
  [ ! -p "$TIMER_FIFO" ] || /bin/rm -f "$TIMER_FIFO"
  # Keep the service alive for the bounded host diagnostic to capture evidence.
  while :; do sleep 60; done
}

init_timer_fifo() {
  # Recovery has Bash 3.2 before any SDK is installed. Its read timeout uses
  # alarm(), avoiding a separate sleep process for every command and grace period.
  [ ! -e "$TIMER_FIFO" ] || exit 1
  /usr/bin/mkfifo -m 600 "$TIMER_FIFO" || exit 1
  exec 9<> "$TIMER_FIFO" || exit 1
}

flush_outputs() {
  (( ${#PENDING_OUTPUTS[@]} > 0 )) || return 0
  local started=$SECONDS sizes="/tmp/native-diagnostic-$$.sizes" proof_size output_size raw_size
  local raw_count=0 raw_valid=1 pending_count=${#PENDING_OUTPUTS[@]}
  local bounded="/tmp/native-diagnostic-$$.flush"
  # One bounded native copy per group, rather than tail/stat startup per command.
  # Keep native byte-oriented copying: Bash 3.2 read -n would read large outputs
  # one byte per system call. Small scalar reads below have a separate tight bound.
  /usr/bin/tail -c "$MAX_OUTPUT_BYTES" "${PENDING_OUTPUTS[@]}" > "$bounded" || return 1
  /usr/bin/stat -f '%z' "$PROOF_LOG" "$bounded" "${PENDING_OUTPUTS[@]}" > "$sizes" || return 1
  {
    IFS= read -r proof_size; IFS= read -r output_size
    while IFS= read -r raw_size; do
      raw_count=$((raw_count + 1))
      [[ "$raw_size" =~ ^[0-9]+$ ]] && (( raw_size <= MAX_OUTPUT_BYTES )) || raw_valid=0
    done
  } < "$sizes"
  PENDING_OUTPUTS=()
  [[ "$proof_size" =~ ^[0-9]+$ && "$output_size" =~ ^[0-9]+$ ]] || return 1
  (( raw_valid == 1 && raw_count == pending_count )) || return 1
  (( proof_size + output_size + 1024 <= MAX_LOG_BYTES )) || return 1
  /bin/cat "$bounded" >&3 || return 1
  printf '\n[proof-flush] outputs-bytes=%s elapsed=%ss\n' "$output_size" "$((SECONDS - started))" >&3
}

read_scalar() {
  local value status
  # All three values are short native machine/uid/version scalars. Reject excess
  # content instead of accepting a truncated first line as a successful gate.
  IFS= read -r -n 65 -d '' value < "$LAST_OUTPUT"; status=$?
  # EOF is mandatory: the byte bound or a NUL delimiter must never hide a suffix.
  (( status == 1 && ${#value} < 65 )) || return 1
  value=${value%$'\n'}
  [[ "$value" != *$'\n'* ]] || return 1
  SCALAR="$value"
}

cancel_probe() {
  trap '' TERM INT
  if [ -n "$ACTIVE_COMMAND" ]; then
    kill -TERM "$ACTIVE_COMMAND" 2>/dev/null || :
    IFS= read -r -t 2 -u 9 unused || :
    kill -KILL "$ACTIVE_COMMAND" 2>/dev/null || :
    wait "$ACTIVE_COMMAND" 2>/dev/null || :
  fi
  [ -z "$ACTIVE_TIMER" ] || { kill -TERM "$ACTIVE_TIMER" 2>/dev/null || :; wait "$ACTIVE_TIMER" 2>/dev/null || :; }
  ACTIVE_COMMAND=""; ACTIVE_TIMER=""
  finish false probe_cancelled
}

run_command() {
  local name="$1"
  shift
  local process timer exit_code started waited
  LAST_OUTPUT="/tmp/native-diagnostic-$name.out"
  printf '\n[proof-command] %s:' "$name" >&3
  printf ' %s' "$@" >&3
  printf '\n' >&3
  started=$SECONDS
  "$@" > "$LAST_OUTPUT" 2>&1 &
  process=$!
  ACTIVE_COMMAND="$process"
  printf '[proof-start] %s child=%s shell=%s parent=%s seconds=%s\n' "$name" "$process" "$$" "$PPID" "$started" >&3
  (
    trap 'exit 0' TERM INT
    IFS= read -r -t 45 -u 9 unused || :
    printf '[proof-timeout] %s child=%s elapsed=%ss signal=TERM\n' "$name" "$process" "$((SECONDS - started))" >&3
    kill -TERM "$process" 2>/dev/null || :
    IFS= read -r -t 2 -u 9 unused || :
    kill -KILL "$process" 2>/dev/null || :
  ) &
  timer=$!
  ACTIVE_TIMER="$timer"
  wait "$process"
  exit_code=$?
  waited=$SECONDS
  # Includes fork/exec/wait, but excludes timer cleanup and evidence copying.
  printf '[proof-native-wait] %s child=%s elapsed=%ss exit=%s\n' "$name" "$process" "$((waited - started))" "$exit_code" >&3
  kill -TERM "$timer" 2>/dev/null || :
  wait "$timer" 2>/dev/null || :
  ACTIVE_COMMAND=""; ACTIVE_TIMER=""
  printf '[proof-cleanup] %s child=%s elapsed=%ss total=%ss\n' "$name" "$process" "$((SECONDS - waited))" "$((SECONDS - started))" >&3
  printf '[proof-exit] %s\n' "$exit_code" >&3
  LAST_EXIT="$exit_code"
  PENDING_OUTPUTS+=("$LAST_OUTPUT")
  return 0
}

diagnose_failure() {
  run_command kernel /usr/bin/uname -a
  run_command account /usr/bin/id
  run_command context /usr/sbin/sysctl kern.bootargs machdep.cpu.brand_string machdep.cpu.features machdep.cpu.leaf7_features
  run_command parent /bin/ps -p "$$" -p "$PPID" -o pid=,ppid=,comm=
  run_command processes /bin/ps -axo pid,ppid,comm
}

fail_probe() {
  local reason="$1"
  flush_outputs || finish false diagnostic_log_budget_exceeded
  diagnose_failure
  finish false "$reason"
}

init_timer_fifo
trap cancel_probe TERM INT

# Test the required native gates before optional process/CPU diagnostics.
run_command architecture /usr/bin/uname -m
(( LAST_EXIT == 0 )) || fail_probe architecture_probe_failed
read_scalar || fail_probe architecture_output_invalid
architecture="$SCALAR"
[ "$architecture" = x86_64 ] || fail_probe unexpected_guest_architecture
run_command uid /usr/bin/id -u
(( LAST_EXIT == 0 )) || fail_probe uid_probe_failed
read_scalar || fail_probe uid_output_invalid
uid="$SCALAR"
[ "$uid" = 0 ] || fail_probe recovery_account_not_root
run_command platform /usr/bin/sw_vers
platform_exit="$LAST_EXIT"
flush_outputs || finish false diagnostic_log_budget_exceeded
if (( platform_exit != 0 )); then
  run_command system /bin/launchctl print system
  system_exit="$LAST_EXIT"
  run_command arbitration /bin/launchctl print system/com.apple.diskarbitrationd
  arbitration_exit="$LAST_EXIT"
  run_command recovery /bin/launchctl print system/com.apple.recoveryosd
  recovery_exit="$LAST_EXIT"
  printf '[proof-retry] sw_vers once after native service context; same 45-second deadline\n' >&3
  run_command platform-warm /usr/bin/sw_vers
  platform_exit="$LAST_EXIT"
fi
(( platform_exit == 0 )) || fail_probe sw_vers_failed
run_command version /usr/bin/sw_vers -productVersion
(( LAST_EXIT == 0 )) || fail_probe product_version_failed
read_scalar || fail_probe product_version_invalid
os_version="$SCALAR"
[[ "$os_version" =~ ^[0-9]+\.[0-9]+(\.[0-9]+)?$ ]] || fail_probe product_version_invalid
(( ${os_version%%.*} >= 14 )) || fail_probe unsupported_macos_version
flush_outputs || finish false diagnostic_log_budget_exceeded

# Bound readiness independently of the host's 40-minute overall deadline.
readiness_start=$SECONDS
attempt=0
while (( SECONDS - readiness_start < 600 )); do
  attempt=$((attempt + 1))
  printf '\n[readiness-attempt] %s\n' "$attempt" >&3
  run_command disks /usr/sbin/diskutil list physical
  disk_list_exit="$LAST_EXIT"
  if (( disk_list_exit == 0 )); then
    disk_list=$(cat "$LAST_OUTPUT")
    candidates=0
    while IFS= read -r disk; do
      [ -n "$disk" ] || continue
      run_command "info-$disk" /usr/sbin/diskutil info "/dev/$disk"
      (( LAST_EXIT == 0 )) || continue
      info=$(cat "$LAST_OUTPUT")
      if printf '%s\n' "$info" | grep -Eq '^[[:space:]]*(Read-Only (Media|Device)|(Media|Device) Read-Only):[[:space:]]*Yes'; then
        continue
      fi
      printf '%s\n' "$info" | grep -Eq '^[[:space:]]*(Read-Only (Media|Device)|(Media|Device) Read-Only):[[:space:]]*No' || continue
      size=$(printf '%s\n' "$info" | sed -nE 's/^[[:space:]]*Disk Size:.*\(([0-9]+) Bytes\).*/\1/p' | head -n 1)
      [[ "$size" =~ ^[0-9]+$ ]] || continue
      (( size == EXPECTED_BYTES )) || continue
      candidates=$((candidates + 1))
      selected_disk="/dev/$disk"
      disk_bytes="$size"
      printf '[writable-target] %s %s bytes\n' "$selected_disk" "$disk_bytes" >&3
    done < <(printf '%s\n' "$disk_list" | sed -nE 's#^/dev/(disk[0-9]+).*#\1#p')
    (( candidates <= 1 )) || fail_probe ambiguous_writable_64g_disks
    if (( candidates == 1 )); then
      # Re-probe live launchd domains after disk readiness, preserving native exits.
      run_command system_ready /bin/launchctl print system
      system_exit="$LAST_EXIT"
      run_command arbitration_ready /bin/launchctl print system/com.apple.diskarbitrationd
      arbitration_exit="$LAST_EXIT"
      run_command recovery_ready /bin/launchctl print system/com.apple.recoveryosd
      recovery_exit="$LAST_EXIT"
      (( system_exit == 0 && arbitration_exit == 0 && recovery_exit == 0 )) || fail_probe service_domain_not_ready
      finish true native_recovery_and_writable_64g_disk_ready
    fi
  fi
  flush_outputs || finish false diagnostic_log_budget_exceeded
  IFS= read -r -t 5 -u 9 unused || :
done
fail_probe disk_management_or_writable_target_not_ready