#!/usr/bin/env python
#
# Copyright (c) 2013 Contributors to the Freedoom project.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
#  * Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#  * Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#  * Neither the name of the freedoom project nor the names of its
#    contributors may be used to endorse or promote products derived from
#    this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
# IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
# OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
# PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
# LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# ----------------------------------------------------------------------
#
# Config file generator for the DMXGUS lump / config file.
#
# This script generates a GUS config file with instrument mappings for
# 256,512,768 and 1024KB cards. This is done automatically from the config
# in config.py. The instruments to include are selected using statistics
# processed from a collection of well-known Doom WAD files.
#

import re
import sys

import config
import stats

def normalize_stats(stats):
	"""Normalize the gathered instrument statistics.

	Percussion instruments tend to be more widely used, which can give
	them a disproportionate priority. Therefore, generate a "normalized"
	set of statistics that adjust the percussion instruments to be
	roughly equal to the main instruments.
	"""
	main_stats = stats[0:128]
	perc_stats = stats[128:]
	main_av = sum(main_stats) / len(main_stats)
	perc_av = sum(perc_stats) / (len(perc_stats) - 35)

	def adjusted_priority(stat):
		return (float(stat) * main_av) / perc_av

	adjusted_perc_stats = map(adjusted_priority, perc_stats)

	return main_stats + list(adjusted_perc_stats)

def ranked_patches():
	"""Get a list of GUS patches ranked by priority.

	This uses the gathered statistics about use of different instruments
	in Doom WADs and orders them by benefit/cost ratio (where cost is
	the size that the instrument file will occupy in RAM).
	"""
	adjusted_stats = normalize_stats(stats.INSTRUMENT_STATS)
	result = []
	for instr_id, name in config.GUS_INSTR_PATCHES.items():
		priority = float(adjusted_stats[instr_id]) \
		         / config.PATCH_FILE_SIZES[name]
		result.append((priority, name))

	return list(map(lambda x: x[1], reversed(sorted(result))))

def midi_instr_for_name(name):
	"""Given a GUS patch name, find the associated MIDI instrument."""
	for instr_id, instr_name in config.GUS_INSTR_PATCHES.items():
		if name == instr_name:
			return instr_id
	raise KeyError("Unknown instrument: %s" % name)

def patchset_size(mapping):
	"""Given an instrument-instrument mapping patch set, calculate its
	   size.
	"""
	result = 0
	for i1, i2 in mapping.items():
		if i1 == i2:
			name = config.GUS_INSTR_PATCHES[i1]
			result += config.PATCH_FILE_SIZES[name]
	return result

def patchset_to_string(mapping):
	result = []
	for i1, i2 in mapping.items():
		if i1 == i2:
			name = config.GUS_INSTR_PATCHES[i1]
			result.append("%s (%i bytes)" % (
			    name, config.PATCH_FILE_SIZES[name]))
	return "\n".join(result)

def mapping_for_size(size):
	"""Select a set of patches for the given RAM size.

	Args:
	  size: Size in bytes of the GUS RAM.
	Returns:
	  Dictionary mapping from instrument number to instrument number.
	  An instrument that maps to itself is included in the output.
	"""
	# Leave some extra space. The ultramid.ini distributed with the
	# GUS drivers says this:
	#   The libraries are built in such a way as to leave 8K+32bytes
	#   after the patches are loaded for digital audio.
	size -= 32*1024 + 8

	# Get a list of patches sorted by decreasing priority.
	patches = ranked_patches()

	# Start by processing the similarity groups and pointing all
	# instruments in a group to their group leader.
	result = {}

	for group in config.SIMILAR_GROUPS:
		leader = group[0]
		leader_index = midi_instr_for_name(leader)
		for patch in group:
			patch_index = midi_instr_for_name(patch)
			result[patch_index] = leader_index

	# We now have a mapping that should cover every instrument with
	# a fallback. Go through the patches in order of priority and add
	# patches that will fit.
	curr_size = patchset_size(result)
	assert curr_size < size, \
	       "Minimal config for %s will not fit in RAM! (%i):\n%s" % \
	       (size, curr_size, patchset_to_string(result))

	for patch in patches:
		patch_index = midi_instr_for_name(patch)
		patch_size = config.PATCH_FILE_SIZES[patch]

		if result[patch_index] != patch_index \
		   and curr_size + patch_size < size:
			result[patch_index] = patch_index
			curr_size += patch_size

	return result

if len(sys.argv) != 2:
	print("Usage: %s <filename>" % sys.argv[0])
	sys.exit(1)

mappings = (
	mapping_for_size(256 * 1024),
	mapping_for_size(512 * 1024),
	mapping_for_size(768 * 1024),
	mapping_for_size(1024 * 1024)
)

with open(sys.argv[1], "w") as output:
	output.write("# Freedoom GUS config.\n"
	             "# Autogenerated by the gen-ultramid script.\n"
		     "# Please do not manually edit this file!\n")

	for instr_id, name in sorted(config.GUS_INSTR_PATCHES.items()):
		line = "%i, %i, %i, %i, %i, %s" % (
			instr_id,
			mappings[0][instr_id],
			mappings[1][instr_id],
			mappings[2][instr_id],
			mappings[3][instr_id],
			name
		)

		output.write(line + "\n")