Abbreviations, simple

# title: Abbreviations, simple
# source: https://rosettacode.org/wiki/Abbreviations,_simple
# category: Rosetta Code
# difficulty: Intro
# summary: Resolve simple command abbreviations by matching unique prefixes from a fixed command list.
# tags: popular, strings, search, basics
# vibe: 0.2

def commands
  [
    "add",
    "append",
    "commit",
    "copy",
    "delete",
    "insert",
    "move",
    "print",
    "quit"
  ]
end

def matches_for(token)
  results = []
  available = commands
  index = 0
  while index < available.size
    command = available[index]
    if command.index(token.downcase) == 0
      results = results + [command]
    end
    index = index + 1
  end
  results
end

def resolve(token)
  matches = matches_for(token)
  if matches.empty?
    "unknown"
  elsif matches.size == 1
    matches[0]
  else
    "ambiguous"
  end
end

def run
  {
    add: resolve("ad"),
    append: resolve("app"),
    ambiguous: resolve("c"),
    delete: resolve("del"),
    unknown: resolve("zoom")
  }
end