import math
import optparse
import os
import re
import sys

import cairo

FONT_NAME = "Bitstream Vera Sans"
FONT_SIZE = 8
# how many pixels for a second on the timeline
pixels_per_second = 1000
# how many pixels for one line of log
pixels_per_line = 10

PLOT_WIDTH = 1400
TIME_SCALE_WIDTH = 20
SYSCALL_MARKER_WIDTH = 20
LOG_TEXT_XPOS = 400
LOG_MARKER_WIDTH = 20
BACKGROUND_COLOR = (0, 0, 0)

# ... snip ....


class SyscallParser:

# ... snip ....

def compute_syscall_metrics(syscalls):
    num_syscalls = len(syscalls)

    metrics = Metrics()
    metrics.width = PLOT_WIDTH

    last_timestamp = syscalls[num_syscalls - 1].timestamp
    num_seconds = int(math.ceil(last_timestamp))

    # this works
    #
    metrics.height = max(num_seconds * pixels_per_second,
                         num_syscalls * pixels_per_line)
    
    # this gives:
    # UnboundLocalError: local variable 'pixels_per_second' referenced before assignment"
    #
    time_height = num_seconds * pixels_per_second
    line_height = num_syscalls * pixels_per_line
    if time_height > line_height:
        metrics.height = time_height
        pixels_per_line = metrics.height / num_syscalls
    else:
        metrics.height = line_height
        pixels_per_second = metrics.height / num_seconds