#!/usr/bin/env python

'''
usage:   rotate.py my.pdf rotation [page[range] ...]
         eg. rotate.py 270 1-3 5 7-9

        Rotation must be multiple of 90 degrees, clockwise.

Creates rotate.my.pdf with selected pages rotated.  Rotates all by default.

'''

import sys
import os

from pdfrw import PdfReader, PdfWriter

inpfn = sys.argv[1]
rotate = sys.argv[2]
ranges = sys.argv[3:]

rotate = int(rotate)
assert rotate % 90 == 0

ranges = [[int(y) for y in x.split('-')] for x in ranges]
outfn = 'rotate.%s' % os.path.basename(inpfn)
trailer = PdfReader(inpfn)
pages = trailer.pages

if not ranges:
    ranges = [[1, len(pages)]]

for onerange in ranges:
    onerange = (onerange + onerange[-1:])[:2]
    for pagenum in range(onerange[0]-1, onerange[1]):
        pages[pagenum].Rotate = (int(pages[pagenum].inheritable.Rotate or
                                     0) + rotate) % 360

outdata = PdfWriter(outfn)
outdata.trailer = trailer
outdata.write()