#!/usr/bin/env ruby

require 'date'

$possible_devices = { "SIGMA DP2 Merrill" => "dp2m", "FP2" => "fp2", "Canon EOS 1000D" => "1000d", "iPad Air" => "ipadair", "iPhone 5s" => "iphone5s", "iPhone SE" => "iphonese", "IQ180" => "iq180", "iPhone XR" => "iphonexr", "NIKON D70" => "d70" }
$possible_devices.default = "unknown-device"

file_ext = ARGV[0]
if !file_ext
  file_ext = "jpg"
end

if ARGV[1]
  $possible_devices.default = ARGV[1]
end

ids = []
while line = STDIN.gets # list of files
  a = line.split('.')
  a.pop
  ids << a.join('.')
end

used_prefixes = {} # prefix -> 0..N

def parse_timestamp s
  d = s.split(':', 2)[1]
  d.strip!
  d.gsub!(/^(\d\d\d\d):(\d\d):(\d\d)/, "\\1-\\2-\\3")
  return DateTime.parse d
end

def determine_datetime dts, subsec=nil
  dt = dts.min  # get the actual original date
  if subsec != nil and subsec.to_i > 0  # add sub-seconds if available
    if dt.strftime("%L") == "000"
      s = format_datetime(dt)+".#{subsec}"
      dt = DateTime.parse s
    end
  end
  return dt
end

def format_datetime dt
  if dt.strftime("%L") == "000"
    return dt.strftime("%Y-%m-%dT%H:%M:%S")
  else
    return dt.strftime("%Y-%m-%dT%H:%M:%S.%L")
  end
end

def get_possible_device s
  s.strip!
  s.downcase!
  $possible_devices.each { |k,v|
    if s.downcase.start_with? k.downcase
      return v
    end
  }
  return $possible_devices.default
end

def parse_device s
  d = s.split(':', 2)[1]
  return get_possible_device d
end

def determine_device a
  a.each { |s|
    if s != $possible_devices.default
      return s
    end
  }
  return $possible_devices.default
end

ids.each do |i|
  exif = `exiftool "#{i}.#{file_ext}" 2>/dev/null`
  a = exif.split "\n"
  timestamps = []
  subsec_time = nil
  devices = []
  a.each { |j|
    if j.start_with? "Camera Model Name" \
        or j.start_with? "Model" \
        or j.start_with? "Lens Model"
      devices << parse_device(j)
    elsif j.start_with? "Date/Time Original" \
        or j.start_with? "Creation Date" \
        or j.start_with? "Create Date" \
        or j.start_with? "Media Create Date" \
        or j.start_with? "Track Create Date" \
        or j.start_with? "File Modification Date/Time"
      begin
        timestamps << parse_timestamp(j)
      rescue
      end
    elsif j.start_with? "Sub Sec Time Original"
      subsec_time = j.split(':', 2)[1].strip
    end
  }
  if timestamps.size == 0
    puts "No timestamp found"
    exit
  end
  skip = false
  new_prefix = ""
  add = 0
  begin
    t = format_datetime(determine_datetime(timestamps, subsec_time))
    d = determine_device devices
    new_prefix = "#{t}-#{d}"
    add = 1
  rescue
    puts "Cannot determine metadata for #{i}, skipping!"
    skip = true
  end
  next if skip

  while used_prefixes.has_key? new_prefix
    new_prefix = "#{t}-#{add}-#{d}"
    add += 1
  end
  used_prefixes[new_prefix] = true

  Dir.glob("#{i}*").each { |f|
    ext = f.sub("#{i}","")
    if File.exists? "#{new_prefix}#{ext}"
      puts "File exists: #{new_prefix}#{ext} (#{i})!"
      exit
    else
      `mv \"#{i}#{ext}\" #{new_prefix}#{ext}`
    end
  }
end