#!/usr/bin/python
#vim: encoding=utf-8

"""
This module is used to generate png-files for wttr.in queries.
The only exported function are:

* render_ansi(png_file, text, options=None)
* make_wttr_in_png(png_file)

`render_ansi` is the main function of the module,
which does rendering of stream into a PNG-file.

The `make_wttr_in_png` function is a temporary helper function
which is a wraper around `render_ansi` and handles
such tasks as caching, name parsing etc.

`make_wttr_in_png` parses `png_file` name (the shortname) and extracts
the weather query from it. It saves the weather report into the specified file.

The module uses PIL for graphical tasks, and pyte for rendering
of ANSI stream into terminal representation.

TODO:

    * remove make_wttr_in_png
    * remove functions specific for wttr.in
"""

from __future__ import print_function

import sys
import io
import os
import re
import glob

from PIL import Image, ImageFont, ImageDraw
import pyte.screens
import emoji
import grapheme

import requests

from . import unicodedata2

sys.path.insert(0, "..")
import constants
import parse_query
import globals

COLS = 180
ROWS = 100
CHAR_WIDTH = 9
CHAR_HEIGHT = 18
FONT_SIZE = 15
FONT_CAT = {
    'default':      "/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf",
    'Cyrillic':     "/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf",
    'Greek':        "/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf",
    'Arabic':       "/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf",
    'Hebrew':       "/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf",
    'Han':          "/usr/share/fonts/truetype/wqy/wqy-zenhei.ttc",
    'Hiragana':     "/usr/share/fonts/truetype/motoya-l-cedar/MTLc3m.ttf",
    'Katakana':     "/usr/share/fonts/truetype/motoya-l-cedar/MTLc3m.ttf",
    'Hangul':       "/usr/share/fonts/truetype/lexi/LexiGulim.ttf",
    'Braille':      "/usr/share/fonts/truetype/ancient-scripts/Symbola_hint.ttf",
    'Emoji':        "/usr/share/fonts/truetype/ancient-scripts/Symbola_hint.ttf",
}

#
# How to find font for non-standard scripts:
#
#   $ fc-list :lang=ja
#
# GNU/Debian packages, that the fonts come from:
#
#   * fonts-dejavu-core
#   * fonts-wqy-zenhei (Han)
#   * fonts-motoya-l-cedar (Hiragana/Katakana)
#   * fonts-lexi-gulim (Hangul)
#   * fonts-symbola (Braille/Emoji)
#

def make_wttr_in_png(png_name, options=None):
    """ The function saves the weather report in the file and returns None.
    The weather query is coded in filename (in the shortname).
    """

    parsed = _parse_wttrin_png_name(png_name)

    # if location is MyLocation it should be overriden
    # with autodetected location (from options)
    if parsed.get('location', 'MyLocation') == 'MyLocation' \
       or not parsed.get('location', ''):
        del parsed['location']

    if options is not None:
        for key, val in options.items():
            if key not in parsed:
                parsed[key] = val
    url = _make_wttrin_query(parsed)

    headers = {'X-PNG-Query-For': options.get('ip_addr', '1.1.1.1')}
    text = requests.get(url, headers=headers).text

    return render_ansi(text, options=parsed)

def render_ansi(text, options=None):
    """Render `text` (terminal sequence) in a PNG file
    paying attention to passed command line `options`.

    Return: file content
    """

    screen = pyte.screens.Screen(COLS, ROWS)
    screen.set_mode(pyte.modes.LNM)
    stream = pyte.Stream(screen)

    text, graphemes = _fix_graphemes(text)
    stream.feed(text)

    buf = sorted(screen.buffer.items(), key=lambda x: x[0])
    buf = [[x[1] for x in sorted(line[1].items(), key=lambda x: x[0])] for line in buf]

    return _gen_term(buf, graphemes, options=options)

def _color_mapping(color):
    """Convert pyte color to PIL color

    Return: tuple of color values (R,G,B)
    """

    if color == 'default':
        return 'lightgray'
    if color in ['green', 'black', 'cyan', 'blue', 'brown']:
        return color
    try:
        return (
            int(color[0:2], 16),
            int(color[2:4], 16),
            int(color[4:6], 16))
    except (ValueError, IndexError):
        # if we do not know this color and it can not be decoded as RGB,
        # print it and return it as it is (will be displayed as black)
        # print color
        return color
    return color

def _strip_buf(buf):
    """Strips empty spaces from behind and from the right side.
    (from the right side is not yet implemented)
    """

    def empty_line(line):
        "Returns True if the line consists from spaces"
        return all(x.data == ' ' for x in line)

    def line_len(line):
        "Returns len of the line excluding spaces from the right"

        last_pos = len(line)
        while last_pos > 0 and line[last_pos-1].data == ' ':
            last_pos -= 1
        return last_pos

    number_of_lines = 0
    for line in buf[::-1]:
        if not empty_line(line):
            break
        number_of_lines += 1

    if number_of_lines:
        buf = buf[:-number_of_lines]

    max_len = max(line_len(x) for x in buf)
    buf = [line[:max_len] for line in buf]

    return buf

def _script_category(char):
    """Returns category of a Unicode character

    Possible values:
        default, Cyrillic, Greek, Han, Hiragana
    """

    if char in emoji.UNICODE_EMOJI:
        return "Emoji"

    cat = unicodedata2.script_cat(char)[0]
    if char == u'：':
        return 'Han'
    if cat in ['Latin', 'Common']:
        return 'default'
    return cat

def _load_emojilib():
    """Load known emojis from a directory, and return dictionary
    of PIL Image objects correspodent to the loaded emojis.
    Each emoji is resized to the CHAR_HEIGHT size.
    """

    emojilib = {}
    for filename in glob.glob("share/emoji/*.png"):
        character = os.path.basename(filename)[:-4]
        emojilib[character] = \
            Image.open(filename).resize((CHAR_HEIGHT, CHAR_HEIGHT))
    return emojilib

def _gen_term(buf, graphemes, options=None):
    """Renders rendered pyte buffer `buf` and list of workaround `graphemes`
    to a PNG file, and return its content
    """

    if not options:
        options = {}

    current_grapheme = 0

    buf = _strip_buf(buf)
    cols = max(len(x) for x in buf)
    rows = len(buf)

    image = Image.new('RGB', (cols * CHAR_WIDTH, rows * CHAR_HEIGHT))

    buf = buf[-ROWS:]

    draw = ImageDraw.Draw(image)
    font = {}
    for cat in FONT_CAT:
        font[cat] = ImageFont.truetype(FONT_CAT[cat], FONT_SIZE)

    emojilib = _load_emojilib()

    x_pos = 0
    y_pos = 0
    for line in buf:
        x_pos = 0
        for char in line:
            current_color = _color_mapping(char.fg)
            if char.bg != 'default':
                draw.rectangle(
                    ((x_pos, y_pos),
                     (x_pos+CHAR_WIDTH, y_pos+CHAR_HEIGHT)),
                    fill=_color_mapping(char.bg))

            if char.data == "!":
                data = graphemes[current_grapheme]
                current_grapheme += 1
            else:
                data = char.data

            if data:
                cat = _script_category(data[0])
                if cat not in font:
                    globals.log("Unknown font category: %s" % cat)
                if cat == 'Emoji' and emojilib.get(data):
                    image.paste(emojilib.get(data), (x_pos, y_pos))
                else:
                    draw.text(
                        (x_pos, y_pos),
                        data,
                        font=font.get(cat, font.get('default')),
                        fill=current_color)

            x_pos += CHAR_WIDTH * constants.WEATHER_SYMBOL_WIDTH_VTE.get(data, 1)
        y_pos += CHAR_HEIGHT
        #sys.stdout.write('\n')

    if 'transparency' in options:
        transparency = options.get('transparency', '255')
        try:
            transparency = int(transparency)
        except ValueError:
            transparency = 255

        if transparency < 0:
            transparency = 0

        if transparency > 255:
            transparency = 255

        image = image.convert("RGBA")
        datas = image.getdata()

        new_data = []
        for item in datas:
            new_item = tuple(list(item[:3]) + [transparency])
            new_data.append(new_item)

        image.putdata(new_data)

    img_bytes = io.BytesIO()
    image.save(img_bytes, format="png")
    return img_bytes.getvalue()

def _fix_graphemes(text):
    """
    Extract long graphemes sequences that can't be handled
    by pyte correctly because of the bug pyte#131.
    Graphemes are omited and replaced with placeholders,
    and returned as a list.

    Return:
        text_without_graphemes, graphemes
    """

    output = ""
    graphemes = []

    for gra in grapheme.graphemes(text):
        if len(gra) > 1:
            character = "!"
            graphemes.append(gra)
        else:
            character = gra
        output += character

    return output, graphemes


#
# wttr.in related functions
#

def _parse_wttrin_png_name(name):
    """
    Parse the PNG filename and return the result as a dictionary.
    For example:
        input = City_200x_lang=ru.png
        output = {
            "lang": "ru",
            "width": "200",
            "filetype": "png",
            "location": "City"
        }
    """

    parsed = {}
    to_be_parsed = {}

    if name.lower()[-4:] == '.png':
        parsed['filetype'] = 'png'
        name = name[:-4]

    parts = name.split('_')
    parsed['location'] = parts[0]

    for part in parts[1:]:
        if re.match('(?:[0-9]+)x', part):
            parsed['width'] = part[:-1]
        elif re.match('x(?:[0-9]+)', part):
            parsed['height'] = part[1:]
        elif re.match(part, '(?:[0-9]+)x(?:[0-9]+)'):
            parsed['width'], parsed['height'] = part.split('x', 1)
        elif '=' in part:
            arg, val = part.split('=', 1)
            to_be_parsed[arg] = val
        else:
            to_be_parsed[part] = ''

    parsed.update(parse_query.parse_query(to_be_parsed))

    return parsed

def _make_wttrin_query(parsed):
    """Convert parsed data into query name
    """

    for key in ['width', 'height', 'filetype']:
        if key in parsed:
            del parsed[key]

    location = parsed['location']
    del parsed['location']

    args = []
    if 'options' in parsed:
        args = [parsed['options']]
        del parsed['options']
    else:
        args = []

    for key, val in parsed.items():
        args.append('%s=%s' % (key, val))

    args.append('filetype=png')

    url = "http://wttr.in/%s" % location
    if args != []:
        url += "?%s" % ("&".join(args))

    return url