zettelkasten-search.rb

require "sqlite3"
require 'set'
require 'byebug'
# Will be rebuilt at any time. Nice and incremental.
db = SQLite3::Database.new "index.db"

# Keep prefix indexes for "mos*" searches.
#
# TODO: It doesn't seem like SQLITE FTS5 supports synonyms well. That's ok, but
# we're going to want that. We can download this database from Princeton, write
# a parser for it (or use grind(1)). This should allow us to do potentially do
# `OR` queries. Alternatively, and probably better, woluld be to see if Lucene
# supports this.
#
# https://wordnet.princeton.edu/download/current-version
db.execute <<-SQL
  CREATE VIRTUAL TABLE IF NOT EXISTS zettelkasten
    USING fts5(title, body, tags, mtime UNINDEXED, prefix = 3, tokenize = "porter unicode61");
SQL

# Weigh tags higher, and title a bit higher.
db.execute <<-SQL
  INSERT INTO zettelkasten (zettelkasten, rank) VALUES('rank', 'bm25(2.0, 1.0, 5.0, 0.0)');
SQL

raw_existing = db.execute("SELECT title, mtime FROM zettelkasten")
existing = Hash[raw_existing.map { |e| [e[0], Time.parse(e[1]).to_i] }]

Dir["*.md"].each do |path|
  mtime = File.stat(path).mtime

  # Any file that's been modified since its entry in the full-text search index
  # will get updated (or if it doesn't exist, of course).
  if !existing[path]
    contents = File.read(path)
    tags = contents.scan(/#[\w-]+/).join(" ")
    db.execute(<<-SQL, [path, contents, tags, File.stat(path).mtime.to_s])
      INSERT INTO zettelkasten (title, body, tags, mtime) VALUES (?, ?, ?, ?);
    SQL
  elsif mtime.to_i > existing[path] # to_i because the stat may have more precision
    contents = File.read(path)
    tags = contents.scan(/#[\w-]+/).join(" ")
    db.execute(<<-SQL, [contents, tags, mtime.to_s, path])
      UPDATE zettelkasten SET body = ?, tags = ?, mtime = ? WHERE title = ?
    SQL
  end

  existing[path] = 'VISITED'
end

# Delete any entries in the full text index that don't have files!
existing.each do |(path, present)|
  puts db.execute("DELETE FROM zettelkasten WHERE title = ?;", [path]) unless present == 'VISITED'
end

file_cat = ARGV.delete("-f")

# For preview
if file_cat
  if !ARGV[1].empty?
    results = db.execute(<<-SQL, ARGV[0], ARGV[1])
      SELECT rank, highlight(zettelkasten, 1, '\x1b[0;41m', '\x1b[0m')
        FROM zettelkasten WHERE title = ? AND zettelkasten MATCH ? ORDER BY rank;
    SQL
  # This is when it starts and there's no query input...
  else
    results = db.execute(<<-SQL, ARGV[0])
      SELECT rank, body FROM zettelkasten WHERE title = ?;
    SQL
  end
elsif ARGV[0]
  # Ideally we'd use the search to also `cat` instead of using `bat`, in order
  # to provide highlighting within the document.
  results = db.execute(<<-SQL, ARGV.join(" "))
    SELECT rank, highlight(zettelkasten, 0, '\x1b[0;41m', '\x1b[0m')
      FROM zettelkasten WHERE zettelkasten MATCH ? ORDER BY rank;
  SQL
else
  results = db.execute("SELECT title FROM zettelkasten;")
end

results.each do |(_score, content)|
  # puts score
  puts content
end