# coding: utf-8

import os, cairo
from random import choice, random as rnd
from math import radians


# = DATA =======================================================================

def generate_data(print_generated_data):
    set_of_As = ['Столбец №%i' % i for i in range(1,11)]
    set_of_Bs = ['Строка №%i' % i for i in range(1,11)]

    data = {}
    for A in set_of_As:
        for B in set_of_Bs:
            C = rnd() - 0.5
            if C > 0.33-0.5:
                data[A] = data.get(A) or {}
                data[A][B] = C
                if print_generated_data:
                    print('%s : %s = %+f' % (A.ljust(12), B.ljust(12), C))
    return set_of_As, set_of_Bs, data

def data_from_file(filename):
    ## A : B = C
    data = {}
    As, Bs = set(), set()
    for line in open(filename):
        AB, Cstr = line.split('=', 1)
        A, B = map(str.strip, AB.split(':', 1))
        C = float(Cstr)
        data[A] = data.get(A) or {}
        data[A][B] = C
        As |= {A}
        Bs |= {B}
    return sorted(As), sorted(Bs), data


#~ set_of_As, set_of_Bs,  DATA = data_from_file('data.txt')
set_of_As, set_of_Bs,  DATA = generate_data(False)


# = SETUP ======================================================================

COL_WIDTH  = 60
ROW_HEIGHT = 25
BORDER = 10
FIRST_COL_OFFSET = BORDER + 130     # text baseline of the first column header
FIRST_ROW_OFFSET = BORDER + 120     # text baseline of the first row
COL_NAMES_ROTATION = 75
CELL_FORMAT = '%+.3f'
CELL_PADDING_LEFT = 10

FONT = 'Open Sans Light'
#~ FONT = 'Sans'
FONT_SIZE = 14
GRID_ALPHA = 0.05   # color is semirandom :)

FILE_NAME = 'image.png'
#~ FILE_NAME = 'image.svg'


# = DRAWING CONTEXT SETUP ======================================================

WIDTH  = FIRST_COL_OFFSET + len(set_of_As) * COL_WIDTH + BORDER - COL_WIDTH//2
HEIGHT = FIRST_ROW_OFFSET + (len(set_of_Bs)-1) * ROW_HEIGHT + BORDER + \
                                                (ROW_HEIGHT - FONT_SIZE)//2 + 2

class MyCairoContext(cairo.Context):
    def text(c, text, x, y, a=0):
        c.save()
        c.translate(x, y)
        c.rotate(radians(-a))
        c.translate(-x, -y)
        c.move_to(x, y)
        c.show_text(text)
        c.restore()
        c.new_path()

if FILE_NAME.lower().endswith('.svg'):
    SURF = cairo.SVGSurface(FILE_NAME, WIDTH, HEIGHT)
else:
    SURF = cairo.ImageSurface(cairo.FORMAT_ARGB32, WIDTH, HEIGHT)

c = MyCairoContext(SURF)
c.set_source_rgb(1, 1, 1)
c.paint()
c.select_font_face(FONT, cairo.FONT_SLANT_NORMAL, cairo.FONT_WEIGHT_NORMAL)
c.set_font_size(FONT_SIZE)


# = DRAWING ====================================================================

# Column names and grid
y = FIRST_ROW_OFFSET - ROW_HEIGHT//2 - FONT_SIZE
for i, A in enumerate(set_of_As):
    if not i%2:     # vertical grid
        c.set_source_rgba(0, 0, rnd(), GRID_ALPHA)  # grid color
        x = i * COL_WIDTH + FIRST_COL_OFFSET - COL_WIDTH/2
        c.rectangle(x, BORDER, COL_WIDTH, HEIGHT-BORDER*2)
        c.fill()

    c.set_source_rgb(0, rnd(), rnd())   # text color
    x = i * COL_WIDTH + FIRST_COL_OFFSET
    c.text(A, x, y, COL_NAMES_ROTATION)


# Row names and grid
x = BORDER + 10
for i, B in enumerate(set_of_Bs):
    if not i%2:     # horizontal grid
        c.set_source_rgba(rnd(), 0, 0, GRID_ALPHA)  # grid color
        y = i * ROW_HEIGHT + FIRST_ROW_OFFSET - ROW_HEIGHT/2 - FONT_SIZE/2 + 2
        c.rectangle(BORDER, y, WIDTH-BORDER*2, ROW_HEIGHT)
        c.fill()

    c.set_source_rgb(rnd(), rnd(), 0)   # text color
    y = i * ROW_HEIGHT + FIRST_ROW_OFFSET
    c.text(B, x, y)


# Cell data
c.set_source_rgb(0.1, 0.1, 0.1) # text color, dark grey, almost black
for A in DATA:
    for B in DATA[A]:
        C = DATA[A][B]
        x = set_of_As.index(A) * COL_WIDTH  + FIRST_COL_OFFSET - COL_WIDTH/2
        y = set_of_Bs.index(B) * ROW_HEIGHT + FIRST_ROW_OFFSET
        c.text(CELL_FORMAT % C, x + CELL_PADDING_LEFT, y)


# = OUTPUT IF RASTER ===========================================================

if type(SURF) is cairo.ImageSurface:
    SURF.write_to_png(FILE_NAME)
    os.system('feh -F %s' % FILE_NAME)  # 'feh' is an image viewer