#!/usr/bin/env bash
# vim: set filetype=ruby isk=@,48-57,_,192-255:
#
#     ____      ____
#    / __/___  / __/
#   / /_/_  / / /_
#  / __/ / /_/ __/
# /_/   /___/_/    Fuzzy finder for your shell
#
# URL:         https://github.com/junegunn/fzf
# Author:      Junegunn Choi
# License:     MIT
# Last update: October 24, 2013
#
# Copyright (c) 2013 Junegunn Choi
#
# MIT License
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

exec /usr/bin/env ruby -x "$0" $* 3>&1 1>&2 2>&3
#!ruby
# encoding: utf-8

require 'thread'
require 'ostruct'
require 'curses'

MAX_SORT_LEN = 500
C = Curses

@main     = Thread.current
@new      = []
@lists    = []
@query    = ''
@mtx      = Mutex.new
@smtx     = Mutex.new
@cv       = ConditionVariable.new
@count    = 0
@cursor_x = 0
@vcursor  = 0
@matches  = []
@stat     = OpenStruct.new(:hit => 0, :partial_hit => 0,
                           :prefix_hit => 0, :search => 0)

def max_items; C.lines - 2; end
def cursor_y;  C.lines - 1; end
def cprint str, col
  C.attron  C.color_pair(col) | C::A_BOLD
  C.addstr  str
  C.attroff C.color_pair(col) | C::A_BOLD
end

def print_input
  C.setpos cursor_y, 0
  C.clrtoeol
  cprint '> ',   1
  cprint @query, 2
end

def print_info msg = nil
  C.setpos cursor_y - 1, 0
  C.clrtoeol
  C.addstr "  #{@matches.length}/#{@count}#{msg}"
end

def refresh
  C.setpos cursor_y, 2 + ulen(@query[0, @cursor_x])
  C.refresh
end

def ctrl char
  char.to_s.ord - 'a'.ord + 1
end

if RUBY_VERSION.split('.').map { |e| e.rjust(3, '0') }.join > '001009'
  def ulen str
    expr = '\p{Han}|\p{Katakana}|\p{Hiragana}|\p{Hangul}'
    str.gsub(Regexp.new(expr), '  ').length
  end
else
  def ulen str
    str.length
  end

  class String
    def ord
      self.unpack('c').first
    end
  end
end

C.init_screen
C.start_color
C.raw
C.noecho
C.init_pair 1, C::COLOR_BLUE,   C::COLOR_BLACK
C.init_pair 2, C::COLOR_WHITE,  C::COLOR_BLACK
C.init_pair 3, C::COLOR_YELLOW, C::COLOR_BLACK
C.init_pair 4, C::COLOR_RED,    C::COLOR_BLACK

@read =
  if $stdin.tty?
    if !`which find`.empty?
      IO.popen("find * -path '*/\\.*' -prune -o -type f -print 2> /dev/null")
    else
      exit 1
    end
  else
    $stdin
  end

reader = Thread.new {
  while line = @read.gets
    @mtx.synchronize do
      @new << line.chomp
      @cv.broadcast
    end
  end
}

searcher = Thread.new {
  fcache     = {}
  matches    = []
  new_length = 0
  pquery     = nil
  vcursor    = 0
  pvcursor   = nil
  zz         = [0, 0]

  begin
    while true
      query_changed = nil
      new_items     = nil
      vcursor_moved = nil
      @mtx.synchronize do
        while true
          new_items     = !@new.empty?
          query_changed = pquery   != @query
          vcursor_moved = pvcursor != @vcursor

          if !new_items && !query_changed && !vcursor_moved
            @cv.wait @mtx
            next
          end

          break
        end

        if new_items
          @lists << [@new, {}]
          @count += @new.length

          @new   = []
          fcache = {}
        end

        pquery   = @query
        pvcursor = @vcursor
      end#mtx

      new_search = new_items || query_changed
      if new_search
        regexp = pquery.empty? ? nil :
          Regexp.new(pquery.each_char.inject('') { |sum, e|
            e = Regexp.escape e
            sum << "#{e}[^#{e}]*?"
          }, Regexp::IGNORECASE)

        if fcache.has_key?(pquery)
          @stat.hit += 1
        else
          @smtx.synchronize do
            print_info ' ..'
            refresh
          end unless pquery.empty?
        end
        matches = fcache[pquery] ||= @lists.map { |pair|
          list, cache = pair

          if cache[pquery]
            @stat.partial_hit += 1
            cache[pquery]
          else
            prefix_cache = nil
            (pquery.length - 1).downto(1) do |len|
              prefix = pquery[0, len]
              if prefix_cache = cache[prefix]
                @stat.prefix_hit += 1
                break
              end
            end

            cache[pquery] ||= (prefix_cache ? prefix_cache.map(&:first) : list).map { |line|
              if regexp
                md = line.match regexp
                md ? [line, md.offset(0)] : nil
              else
                [line, zz]
              end
            }.compact
          end
        }.flatten(1)
        @stat.search += 1

        new_length = matches.length
        if new_length <= MAX_SORT_LEN
          matches.replace matches.sort_by { |pair|
            line, offset = pair
            [offset.last - offset.first, line.length, line]
          }
        end
      end#new matches

      # This small delay reduces the number of partial lists.
      sleep 0.2 if !query_changed && !vcursor_moved

      prev_length = @matches.length
      if vcursor_moved || new_search
        vcursor =
          @mtx.synchronize do
            @matches = matches
            @vcursor = [0, [@vcursor, new_length - 1, max_items - 1].min].max
          end
      end

      # Output
      @smtx.synchronize do
        if new_length < prev_length
          prev_length.downto(new_length) do |idx|
            C.setpos cursor_y - idx - 2, 0
            C.clrtoeol
          end
        end

        maxc = C.cols - 3
        matches[0, max_items].each_with_index do |item, idx|
          next if !new_search && !((vcursor-1)..(vcursor+1)).include?(idx)

          line, offset = item
          row = cursor_y - idx - 2
          chosen = idx == vcursor

          if line.length > maxc
            line = line[0, maxc] + '..'
          end

          C.setpos row, 0
          C.clrtoeol
          C.attron C.color_pair(3) | C::A_BOLD if chosen

          b, e = offset
          e = [e, maxc].min
          if b < maxc && b < e
            C.addstr line[0, b]
            cprint   line[b...e], chosen ? 4 : 1
            C.attron C.color_pair(3) | C::A_BOLD if chosen
            C.addstr line[e..-1]
          else
            C.addstr line
          end
          C.attroff C.color_pair(3) | C::A_BOLD if chosen
        end

        print_info
        print_input
        refresh
      end
    end
  rescue Exception => e
    @main.raise e
  end
}

got = nil
begin
  tty     = IO.open(IO.sysopen('/dev/tty'), 'r')
  input   = ''
  cursor  = 0
  actions = {
    :nop     => proc {},
    ctrl(:c) => proc { exit 1 },
    ctrl(:d) => proc { exit 1 if input.empty? },
    ctrl(:m) => proc {
      @mtx.synchronize do
        got = @matches.fetch(@vcursor, [])[0]
      end
      exit 0
    },
    ctrl(:u) => proc { input = input[cursor..-1]; cursor = 0 },
    ctrl(:a) => proc { cursor = 0 },
    ctrl(:e) => proc { cursor = input.length },
    ctrl(:j) => proc {
      @mtx.synchronize do
        @vcursor = [0, @vcursor - 1].max
        @cv.broadcast
      end
    },
    ctrl(:k) => proc {
      @mtx.synchronize do
        @vcursor = [0, [@matches.length - 1, @vcursor + 1].min].max
        @cv.broadcast
      end
    },
    ctrl(:w) => proc {
      ridx   = (input[0...cursor - 1].rindex(/\S\s/) || -2) + 2
      input  = input[0...ridx] + input[cursor..-1]
      cursor = ridx
    },
    127 => proc { input[cursor -= 1] = '' if cursor > 0 },
    :left => proc { cursor = [0, cursor - 1].max },
    :right => proc { cursor = [input.length, cursor + 1].min },
  }.tap { |actions|
    actions[ctrl :b] = actions[:left]
    actions[ctrl :f] = actions[:right]
    actions[ctrl :h] = actions[127]
    actions[ctrl :n] = actions[ctrl :j]
    actions[ctrl :p] = actions[ctrl :k]
  }

  while true
    ord = tty.getc.ord
    if ord == 27
      ord = tty.getc.ord
      if ord == 91
        ord = case tty.getc.ord
              when 68 then :left
              when 67 then :right
              when 66 then ctrl(:j)
              when 65 then ctrl(:k)
              else :nop
              end
      end
    end

    actions.fetch(ord, proc { |ord|
      char = [ord].pack('U*')
      if char =~ /[[:print:]]/
        input.insert cursor, char
        cursor += 1
      end
    }).call(ord)

    # Dispatch key event
    @mtx.synchronize do
      @query = input.dup
      @cv.broadcast
    end

    # Update user input
    @smtx.synchronize do
      @cursor_x = cursor
      print_input
      refresh
    end
  end
ensure
  C.close_screen
  $stderr.puts got if got
end