#!/usr/bin/env python
# SPDX-License-Identifier: BSD-3-Clause
#
# Script to generate text graphics using the "small" (HUD) font.
#

from glob import glob
import sys
import re

from common import *

# Background color for output files.
BACKGROUND_COLOR = '#00ffff'

# Width of a space character in pixels.
SPACE_WIDTH = 4

# Height of the font.
FONT_HEIGHT = 8

# Regexp to match dimensions/x,y coordinate pair.
DIMENSION_MATCH_RE = re.compile(r'(\d+)[x,](\d+)')

class Font(object):
	def __init__(self):
		self.get_font_widths()

	def compile_kerning_table(self, kerning_table):
		"""Given a dictionary of kerning patterns, compile Regexps."""

		result = {}
		for pattern, adjust in kerning_table.items():
			result[re.compile(pattern)] = adjust
		return result

	def get_font_widths(self):
		charfiles = glob('../stcfn*.gif')
		self.char_widths = {}
		for c in range(128):
			filename = self.char_filename(chr(c))
			if filename not in charfiles:
				continue
			w, _ = get_image_dimensions(filename)
			self.char_widths[chr(c)] = w

	def __contains__(self, c):
		return c in self.char_widths

	def char_width(self, c):
		return self.char_widths[c]

	def char_filename(self, c):
		return '../stcfn%03d.gif' % (ord(c))

	def draw_commands_for_text(self, text, x, y):
		text = text.upper()
		result = []

		x1, y1 = x, y

		for c in text:
			if c == '\n':
				y1 += FONT_HEIGHT
				x1 = x
			elif c == ' ':
				x1 += SPACE_WIDTH

			if c not in self:
				continue

			filename = self.char_filename(c)
			result.extend([
				'-draw',
				'image over %i,%i 0,0 "%s"' %
				    (x1, y1, filename)
			])
			x1 += self.char_width(c)

		return result


def parse_command_line(args):
	if len(args) < 4 or (len(args) % 2) != 0:
		return None

	result = {
		'filename': args[0],
		'strings': [],
	}

	m = DIMENSION_MATCH_RE.match(args[1])
	if not m:
		return None
	result['dimensions'] = (int(m.group(1)), int(m.group(2)))

	i = 2
	while i < len(args):
		m = DIMENSION_MATCH_RE.match(args[i])
		if not m:
			return None

		xy = (int(m.group(1)), int(m.group(2)))

		result['strings'].append((xy, args[i + 1]))
		i += 2

	return result


args = parse_command_line(sys.argv[1:])

if not args:
	print("Usage: smtextgen <filename> <size> [...text commands...]")
	print("Where each text command looks like:")
	print("  [x,y] [text]")
	sys.exit(0)

smallfont = Font()

command_line = [
	CONVERT_COMMAND,
	'-size', '%ix%i' % args['dimensions'],
	'xc:none',
]

for xy, string in args['strings']:
	# Allow contents of a file to be included with special prefix:
	if string.startswith('include:'):
		with open(string[8:]) as f:
			string = f.read()

	# Allow special notation to indicate an image file to just draw
	# rather than rendering a string.
	if string.startswith('file:'):
		command_line.extend((
			'-draw',
			'image over %i,%i 0,0 "%s"' % (
				xy[0], xy[1], string[5:]),
		))
	else:
		command_line.extend(smallfont.draw_commands_for_text(
		    string, xy[0], xy[1]))

command_line.extend((
	'-background', BACKGROUND_COLOR,
	'-flatten', args['filename'],
))

invoke_command(command_line)