#!/bin/bash

if [ -z "$1" ]; then
  echo "Markov chain generator."
  echo "Usage: $0 filename.txt"
  exit 1
fi

line_count=$(wc -l "$1")
line_count="${line_count%% *}"

declare -A counts
declare -A totals

current_line=0
prev_word=""
while read -r line; do
  current_line=$(($current_line + 1))
  for word in $line; do
    if [[ -z "$word" ]]; then
      continue
    fi

    if [ -n "$prev_word" ]; then
      counts["$prev_word,$word"]=$((counts["$prev_word,$word"] + 1))
      totals["$prev_word"]=$((totals["$prev_word"] + 1))
    fi
    prev_word="$word"
  done
  echo "Parsing... ($current_line/$line_count)"
done < "$1"

output_file="output.sql"
origin_name="$1"

> "$output_file"

echo "Packing up..."

escape_sql() {
  local s="$1"
  s="${s//\'/\'\'}"
  s="${s//\\/\\\\}"
  echo "$s"
}

current_line=0
line_count=${#counts[@]}

for key in "${!counts[@]}"; do
  current_line=$((current_line + 1))
  IFS=',' read -r from to <<< "$key"
  efrom=$(escape_sql "$from")
  eto=$(escape_sql "$to")
  ename=$(escape_sql "$origin_name")
  weight=${counts["$key"]}
  echo "INSERT INTO chains(origin_name, from_word, to_word, weight) VALUES ('$ename', '$efrom', '$eto', $weight);" >> "$output_file"
  echo "Packing up... ($current_line/$line_count)"
done

echo "Done! Markov chain output saved to '$output_file'! Feed your database with it."