#!/usr/bin/env bash
set -euo pipefail
log_info(){ echo "[INFO]  $(date -Iseconds) $*"; }
log_warn(){ echo "[WARN]  $(date -Iseconds) $*" >&2; }
log_error(){ echo "[ERROR] $(date -Iseconds) $*" >&2; }
die(){ log_error "$*"; exit 1; }
need(){ command -v "$1" >/dev/null 2>&1 || die "Missing required tool: $1"; }

confirm_gate() {
  : "${DRY_RUN:=1}"
  : "${REQUIRE_CONFIRM:=1}"
  : "${CONFIRM_PHRASE:=I UNDERSTAND THIS WILL HASH FILES AND EMIT A ROOT}"
  [[ "$DRY_RUN" == "0" ]] || die "DRY_RUN=$DRY_RUN (set DRY_RUN=0)."
  if [[ "$REQUIRE_CONFIRM" == "1" ]]; then
    echo "Type to confirm:"
    echo "  $CONFIRM_PHRASE"
    read -r input
    [[ "$input" == "$CONFIRM_PHRASE" ]] || die "Confirmation phrase mismatch."
  fi
}

pick_hasher() {
  if command -v b3sum >/dev/null 2>&1; then echo "b3sum"
  elif command -v blake3 >/dev/null 2>&1; then echo "blake3"
  else die "Need b3sum or blake3 installed."
  fi
}

hash_file() {
  local hasher="$1" file="$2"
  if [[ "$hasher" == "b3sum" ]]; then b3sum "$file" | awk '{print $1}'
  else blake3 "$file" | awk '{print $1}'
  fi
}

hash_pair_hex() {
  local hasher="$1" left="$2" right="$3"
  local tmp; tmp="$(mktemp)"
  printf "%s%s" "$left" "$right" > "$tmp"
  local h
  if [[ "$hasher" == "b3sum" ]]; then h="$(b3sum "$tmp" | awk '{print $1}')"
  else h="$(blake3 "$tmp" | awk '{print $1}')"
  fi
  rm -f "$tmp"
  printf "%s" "$h"
}

json_escape() {
  local s="$1"
  s="${s//\\/\\\\}"; s="${s//\"/\\\"}"; s="${s//$'\n'/\\n}"
  printf "%s" "$s"
}