#!/usr/bin/env bash
# table-to-csv.sh — convert a Cloverleaf .tbl file to CSV.
#
# Reverses csv-to-table.sh. Skips the prologue, dflt= line, encoded= meta,
# comment lines, and #-separator lines; emits "input,output" rows.
#
# Usage:
#   table-to-csv.sh [FILE]                     # file or stdin
#   table-to-csv.sh --with-header [FILE]       # emit "input,output" header
#   table-to-csv.sh --delim ';' [FILE]         # output delimiter (default ',')
#   table-to-csv.sh --include-meta [FILE]      # also emit prologue/default rows
set -o pipefail

usage() { sed -n '2,12p' "$0"; exit 0; }

INPUT=""
WITH_HEADER=0
DELIM=','
INCLUDE_META=0

while [ $# -gt 0 ]; do
  case "$1" in
    --with-header)  WITH_HEADER=1 ;;
    --delim)        shift; DELIM="$1" ;;
    --include-meta) INCLUDE_META=1 ;;
    -h|--help)      usage ;;
    -*)             echo "table-to-csv: unknown flag: $1" >&2; exit 2 ;;
    *)              INPUT="$1" ;;
  esac
  shift
done

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

[ "$WITH_HEADER" = "1" ] && printf 'input%soutput\n' "$DELIM"

awk -v D="$DELIM" -v META="$INCLUDE_META" '
  function csv_escape(s,    needs_q) {
    needs_q = (index(s, D) > 0 || index(s, "\"") > 0 || index(s, "\n") > 0)
    gsub(/"/, "\"\"", s)
    if (needs_q) return "\"" s "\""
    return s
  }
  /^[[:space:]]*$/ { next }
  /^[[:space:]]*#/ { next }
  /^prologue$/ { in_prologue=1; next }
  /^end_prologue$/ { in_prologue=0; next }
  in_prologue { next }
  /^dflt=/ {
    if (META == "1") {
      val = $0; sub(/^dflt=/, "", val)
      print "__dflt__" D csv_escape(val)
    }
    next
  }
  /^encoded=/ { next }
  {
    line = $0
    gsub(/^[[:space:]]+|[[:space:]]+$/, "", line)
    if (line == "") next
    if (waiting_for_output) {
      print csv_escape(pending_input) D csv_escape(line)
      pending_input = ""
      waiting_for_output = 0
    } else {
      pending_input = line
      waiting_for_output = 1
    }
  }
' "${INPUT:-/dev/stdin}"