#!/usr/bin/env bash
# csv-to-table.sh — convert a 2-column CSV into Cloverleaf .tbl format.
#
# Input CSV (with or without header):
#   input,output
#   12345,M
#   12346,F
#   ...
#
# Output Cloverleaf .tbl:
#   # Generated by csv-to-table.sh
#   prologue
#       who:      <user>
#       date:     <iso8601>
#       outname:  output
#       inname:   input
#       bidir:    0
#       type:     tbl
#       version:  7.0
#   end_prologue
#   dflt=__non-existent__
#   #
#   12345
#   M
#   encoded=0,0
#   #
#   12346
#   F
#   ...
#
# Usage:
#   csv-to-table.sh [FILE] [--default VALUE] [--bidir 0|1] [--has-header]
#                   [--in-delim CHAR]   # default ','
#                   [--user NAME]       # default $USER
#                   [--out PATH]        # default stdout
set -o pipefail

usage() { sed -n '2,30p' "$0"; exit 0; }

INPUT=""
DEFAULT="__non-existent__"
BIDIR=0
HAS_HEADER=0
DELIM=','
USER_NAME="${USER:-larry}"
OUT_FILE=""

while [ $# -gt 0 ]; do
  case "$1" in
    --default)    shift; DEFAULT="$1" ;;
    --bidir)      shift; BIDIR="$1" ;;
    --has-header) HAS_HEADER=1 ;;
    --in-delim)   shift; DELIM="$1" ;;
    --user)       shift; USER_NAME="$1" ;;
    --out)        shift; OUT_FILE="$1" ;;
    -h|--help)    usage ;;
    -*)           echo "csv-to-table: unknown flag: $1" >&2; exit 2 ;;
    *)            INPUT="$1" ;;
  esac
  shift
done

[ -z "$INPUT" ] || [ -f "$INPUT" ] || { echo "csv-to-table: no such file: $INPUT" >&2; exit 2; }

emit() {
  cat <<EOF
# Generated by larry-anywhere csv-to-table.sh
prologue
    who:        ${USER_NAME}
    date:       $(date -Iseconds 2>/dev/null || date)
    outname:    output
    inname:     input
    bidir:      ${BIDIR}
    type:       tbl
    version:    7.0
end_prologue
#
dflt=${DEFAULT}
#
EOF
  awk -F"$DELIM" -v has_header="$HAS_HEADER" '
    NR == 1 && has_header == 1 { next }
    NF >= 2 {
      # Trim whitespace
      gsub(/^[ \t"]+|[ \t"]+$/, "", $1)
      gsub(/^[ \t"]+|[ \t"]+$/, "", $2)
      if ($1 == "") next
      print $1
      print $2
      print "encoded=0,0"
      print "#"
    }
  ' "${INPUT:-/dev/stdin}"
}

if [ -n "$OUT_FILE" ]; then
  mkdir -p "$(dirname "$OUT_FILE")" 2>/dev/null
  emit > "$OUT_FILE"
  printf 'csv-to-table: wrote %s\n' "$OUT_FILE" >&2
else
  emit
fi