# -*- coding: utf-8 -*-
# Copyright (c) 2013, Michael Nooner
# All rights reserved.

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"""This module is used to create QR Codes. It is designed to be as simple and
as possible. It does this by using sane defaults and autodetection to make
creating a QR Code very simple.

It is recommended that you use the :func:`pyqrcode.create` function to build the
QRCode object. This results in cleaner looking code.

Examples:
        >>> import pyqrcode
        >>> import sys
        >>> url = pyqrcode.create('http://uca.edu')
        >>> url.svg(sys.stdout, scale=1)
        >>> url.svg('uca.svg', scale=4)
        >>> number = pyqrcode.create(123456789012345)
        >>> number.png('big-number.png')
"""

#Imports required for 2.7 support
from __future__ import absolute_import, division, print_function, with_statement, unicode_literals

from . import tables
from . import builder as builder

try:
    str = unicode  # Python 2
except NameError:
    pass

def create(content, error='H', version=None, mode=None, encoding='utf-8'):
    """When creating a QR code only the content to be encoded is required,
    all the other properties of the code will be guessed based on the
    contents given. This function will return a :class:`QRCode` object.

    Unless you are familiar with QR code's inner workings
    it is recommended that you just specify the *content* and nothing else.
    However, there are cases where you may want to specify the various
    properties of the created code manually, this is what the other
    parameters do. Below, you will find a lengthy explanation of what
    each parameter is for. Note, the parameter names and values are taken
    directly from the standards. You may need to familiarize yourself
    with the terminology of QR codes for the names and their values to
    make sense.

    The *error* parameter sets the error correction level of the code. There
    are four levels defined by the standard. The first is level 'L' which
    allows for 7% of the code to be corrected. Second, is level 'M' which
    allows for 15% of the code to be corrected. Next, is level 'Q' which
    is the most common choice for error correction, it allow 25% of the
    code to be corrected. Finally, there is the highest level 'H' which
    allows for 30% of the code to be corrected. There are several ways to
    specify this parameter, you can use an upper or lower case letter,
    a float corresponding to the percentage of correction, or a string
    containing the percentage. See tables.modes for all the possible
    values. By default this parameter is set to 'H' which is the highest
    possible error correction, but it has the smallest available data
    capacity.

    The *version* parameter specifies the size and data capacity of the
    code. Versions are any integer between 1 and 40. Where version 1 is
    the smallest QR code, and version 40 is the largest. If this parameter
    is left unspecified, then the contents and error correction level will
    be used to guess the smallest possible QR code version that the
    content will fit inside of. You may want to specify this parameter
    for consistency when generating several QR codes with varying amounts
    of data. That way all of the generated codes would have the same size.

    The *mode* parameter specifies how the contents will be encoded. By
    default, the best possible encoding for the contents is guessed. There
    are four possible encoding methods. First, is 'numeric' which is
    used to encode integer numbers. Next, is 'alphanumeric' which is
    used to encode some ASCII characters. This mode uses only a limited
    set of characters. Most problematic is that it can only use upper case
    English characters, consequently, the content parameter will be
    subjected to str.upper() before encoding. See tables.ascii_codes for
    a complete list of available characters. We then have 'binary' encoding
    which just encodes the bytes directly into the QR code (this encoding
    is the least efficient). Finally, there is 'kanji'  encoding (i.e.
    Japanese characters), this encoding is unimplemented at this time.

    The *encoding* parameter specifies how the content will be interpreted.
    This parameter only matters if the *content* is a string, unicode, or
    byte array type. This parameter must be a valid encoding string. It will
    be passed the *content*'s encode/decode methods.
    """
    return QRCode(content, error, version, mode, encoding)

class QRCode:
    """This class represents a QR code. To use this class simply give the
    constructor a string representing the data to be encoded, it will then
    build a code in memory. You can then save it in various formats. Note,
    codes can be written out as PNG files but this requires the PyPNG module.
    You can find the PyPNG module at http://packages.python.org/pypng/.

    Examples:
        >>> from pyqrcode import QRCode
        >>> import sys
        >>> url = QRCode('http://uca.edu')
        >>> url.svg(sys.stdout, scale=1)
        >>> url.svg('uca.svg', scale=4)
        >>> number = QRCode(123456789012345)
        >>> number.png('big-number.png')

    .. note::
        For what all of the parameters do, see the :func:`pyqrcode.create`
        function.
    """
    def __init__(self, content, error='H', version=None, mode=None,
                 encoding='utf-8'):

        #Store the encoding for use later
        if encoding is None:
            encoding = 'utf-8'
        self.encoding = encoding

        if version is not None:
            if 1 <= version <= 40:
                self.version = version
            else:
                raise ValueError("Illegal version {0}, version must be between "
                                 "1 and 40.".format(version))


        #Decode a 'byte array' contents into a string format
        if isinstance(content, bytes):
            self.data = content.decode(encoding)

        #Encode a string an encoding
        elif hasattr(content, 'encode'):
            #Try encoding using the given value
            if encoding is not None:
                self.data = content.encode(encoding)
            else:
                # Try to use standard-conforming encoding
                try:
                    self.data = content.encode('iso-8859-1')
                    self.encoding = 'iso-8859-1'
                except UnicodeError:
                    self.data = content.encode('utf-8')
                    self.encoding = 'utf-8'

        #The contents are not a byte array or string, so
        #try naively converting to a string representation.
        else:
            #Python2 vs. Python3 compatibility
            try:
                self.data = unicode(content)
            except NameError:
                self.data = str(content)


        #Guess the mode of the code, this will also be used for
        #error checking
        guessed_content_type = self._detect_content_type(self.data)

        #Force a passed in mode to be lowercase
        if hasattr(mode, 'lower'):
            mode = mode.lower()

        #Check that the mode parameter is compatible with the contents
        if mode is None:
            #Use the guessed mode
            self.mode = guessed_content_type
            self.mode_num = tables.modes[self.mode]
        elif mode not in tables.modes.keys():
            #Unknown mode
            raise ValueError('{0} is not a valid mode.'.format(mode))
        elif guessed_content_type == 'binary' and \
             tables.modes[mode] != tables.modes['binary']:
            #Binary is only guessed as a last resort, if the
            #passed in mode is not binary the data won't encode
            raise ValueError('The content provided cannot be encoded with '
                             'the mode {}, it can only be encoded as '
                             'binary.'.format(mode))
        elif tables.modes[mode] == tables.modes['numeric'] and \
             guessed_content_type != 'numeric':
            #If numeric encoding is requested make sure the data can
            #be encoded in that format
            raise ValueError('The content cannot be encoded as numeric.')
        else:
            #The data should encode with the passed in mode
            self.mode = mode
            self.mode_num = tables.modes[self.mode]

        #Check that the user passed in a valid error level
        if error in tables.error_level.keys():
            self.error = tables.error_level[error]
        else:
            raise ValueError('{0} is not a valid error '
                             'level.'.format(error))

        #Guess the "best" version
        self.version = self._pick_best_fit(self.data)

        #If the user supplied a version, then check that it has
        #sufficient data capacity for the contents passed in
        if version:
            if version >= self.version:
                self.version = version
            else:
                raise ValueError('The data will not fit inside a version {} '
                                 'code with the given encoding and error '
                                 'level (the code must be at least a '
                                 'version {}).'.format(version, self.version))

        #Build the QR code
        self.builder = builder.QRCodeBuilder(data=self.data,
                                             version=self.version,
                                             mode=self.mode,
                                             error=self.error)

        #Save the code for easier reference
        self.code = self.builder.code

    def __str__(self):
        return repr(self)

    def __unicode__(self):
        return self.__repr__()

    def __repr__(self):
        return "QRCode(content={0}, error='{1}', version={2}, mode='{3}')" \
                .format(repr(self.data), self.error, self.version, self.mode)

    def _detect_content_type(self, content):
        """This method tries to auto-detect the type of the data. It first
        tries to see if the data is a valid integer, in which case it returns
        numeric. Next, it tests the data to see if it is 'alphanumeric.' QR
        Codes use a special table with very limited range of ASCII characters.
        The code's data is tested to make sure it fits inside this limited
        range. If all else fails, the data is determined to be of type
        'binary.'

        Note, encoding 'kanji' and ECI is not yet implemented.
        """
        #See if the data is an integer
        try:
            test = int(content)
            return 'numeric'
        except:
            #Data is not numeric, this is not an error
            pass

        #See if that data is alphanumeric based on the standards
        #special ASCII table
        valid_characters = ''.join(tables.ascii_codes.keys())

        #Force the characters into a byte array
        valid_characters = valid_characters.encode('ASCII')

        try:
            if all(map(lambda x: x in valid_characters, content)):
                return 'alphanumeric'
        except TypeError:
            #This occurs if the content does not contain ASCII characters.
            #Since the whole point of the if statement is to look for ACII
            #characters, the resulting mode should be binary.
            #Hence, this is not an error.
            pass

        #All of the tests failed. The content can only be binary.
        return 'binary'

    def _pick_best_fit(self, content):
        """This method return the smallest possible QR code version number
        that will fit the specified data with the given error level.
        """
        for version in range(1,41):
            #Get the maximum possible capacity
            capacity = tables.data_capacity[version][self.error][self.mode_num]

            #Check the capacity
            if capacity >= len(content):
                return version

        raise ValueError('The data will not fit in any QR code version '
                         'with the given encoding and error level.')

    def get_png_size(self, scale=1, quiet_zone=4):
        """This is method helps users determine what *scale* to use when
        creating a PNG of this QR code. It is meant mostly to be used in the
        console to help the user determine the pixel size of the code
        using various scales.

        This method will return an integer representing the width and height of
        the QR code in pixels, as if it was drawn using the given *scale*.
        Because QR codes are square, the number represents both the width
        and height dimensions.

        The *quiet_zone* parameter sets how wide the quiet zone around the code
        should be. According to the standard this should be 4 modules. It is
        left settable because such a wide quiet zone is unnecessary in many
        applications where the QR code is not being printed.

        Example:
            >>> code = pyqrcode.QRCode("I don't like spam!")
            >>> print(code.get_png_size(1))
            31
            >>> print(code.get_png_size(5))
            155
        """
        return builder._get_png_size(self.version, scale, quiet_zone)

    def show(self, wait=1.2, scale=10, module_color=(0, 0, 0, 255),
            background=(255, 255, 255, 255), quiet_zone=4):
        """Displays this QR code.

        This method is mainly intended for debugging purposes.

        This method saves the output of the `png` method (with a default
        scaling factor of 10) to a temporary file and opens it with the
        standard PNG viewer application or within the standard webbrowser. The
        temporary file is deleted afterwards.

        If this method does not show any result, try to increase the `wait`
        parameter. This parameter specifies the time in seconds to wait till
        the temporary file is deleted. Note, that this method does not return
        until the provided amount of seconds (default: 1.2) has passed.

        The other parameters are simply passed on to the `png` method.
        """
        import os
        import time
        import tempfile
        import webbrowser
        try:  # Python 2
            from urlparse import urljoin
            from urllib import pathname2url
        except ImportError:  # Python 3
            from urllib.parse import urljoin
            from urllib.request import pathname2url

        f = tempfile.NamedTemporaryFile('wb', suffix='.png', delete=False)
        self.png(f, scale=scale, module_color=module_color,
                 background=background, quiet_zone=quiet_zone)
        f.close()
        webbrowser.open_new_tab(urljoin('file:', pathname2url(f.name)))
        time.sleep(wait)
        os.unlink(f.name)

    def png(self, file, scale=1, module_color=(0, 0, 0, 255),
            background=(255, 255, 255, 255), quiet_zone=4):
        """This method writes the QR code out as an PNG image. The resulting
        PNG has a bit depth of 1. The file parameter is used to specify where
        to write the image to. It can either be an writable stream or a
        file path.

        .. note::
            This method depends on the pypng module to actually create the
            PNG file.

        This method will write the given *file* out as a PNG file. The file
        can be either a string file path, or a writable stream. The file
        will not be automatically closed if a stream is given.

        The *scale* parameter sets how large to draw a single module. By
        default one pixel is used to draw a single module. This may make the
        code too small to be read efficiently. Increasing the scale will make
        the code larger. Only integer scales are usable. This method will
        attempt to coerce the parameter into an integer (e.g. 2.5 will become 2,
        and '3' will become 3).

        The *module_color* parameter sets what color to use for the encoded
        modules (the black part on most QR codes). The *background* parameter
        sets what color to use for the background (the white part on most
        QR codes). If either parameter is set, then both must be
        set or a ValueError is raised. Colors should be specified as either
        a list or a tuple of length 3 or 4. The components of the list must
        be integers between 0 and 255. The first three member give the RGB
        color. The fourth member gives the alpha component, where 0 is
        transparent and 255 is opaque. Note, many color
        combinations are unreadable by scanners, so be judicious.

        The *quiet_zone* parameter sets how wide the quiet zone around the code
        should be. According to the standard this should be 4 modules. It is
        left settable because such a wide quiet zone is unnecessary in many
        applications where the QR code is not being printed.

        Example:
            >>> code = pyqrcode.create('Are you suggesting coconuts migrate?')
            >>> code.png('swallow.png', scale=5)
            >>> code.png('swallow.png', scale=5,
                         module_color=(0x66, 0x33, 0x0),      #Dark brown
                         background=(0xff, 0xff, 0xff, 0x88)) #50% transparent white
        """
        builder._png(self.code, self.version, file, scale,
                     module_color, background, quiet_zone)

    def svg(self, file, scale=1, module_color='#000', background=None,
            quiet_zone=4, xmldecl=True, svgns=True, title=None,
            svgclass='pyqrcode', lineclass='pyqrline', omithw=False,
            debug=False):
        """This method writes the QR code out as an SVG document. The
        code is drawn by drawing only the modules corresponding to a 1. They
        are drawn using a line, such that contiguous modules in a row
        are drawn with a single line.

        The *file* parameter is used to specify where to write the document
        to. It can either be a writable stream or a file path.
        The *scale* parameter sets how large to draw
        a single module. By default one pixel is used to draw a single
        module. This may make the code too small to be read efficiently.
        Increasing the scale will make the code larger. Unlike the png() method,
        this method will accept fractional scales (e.g. 2.5).

        Note, three things are done to make the code more appropriate for
        embedding in a HTML document. The "white" part of the code is actually
        transparent. The code itself has a class given by *svgclass* parameter.
        The path making up the QR code uses the class set using the *lineclass*.
        These should make the code easier to style using CSS.

        By default the output of this function is a complete SVG document. If
        only the code itself is desired, set the *xmldecl* to false. This will
        result in a fragment that contains only the "drawn" portion of the code.
        Likewise, you can set the *title* of the document. The SVG name space
        attribute can be suppressed by setting *svgns* to False.

        When True the *omithw* indicates if width and height attributes should
        be omitted. If these attributes are omitted, a ``viewBox`` attribute
        will be added to the document.

        You can also set the colors directly using the *module_color* and
        *background* parameters. The *module_color* parameter sets what color to
        use for the data modules (the black part on most QR codes). The
        *background* parameter sets what color to use for the background (the
        white part on most QR codes). The parameters can be set to any valid
        SVG or HTML color. If the background is set to None, then no background
        will be drawn, i.e. the background will be transparent. Note, many color
        combinations are unreadable by scanners, so be careful.

        The *quiet_zone* parameter sets how wide the quiet zone around the code
        should be. According to the standard this should be 4 modules. It is
        left settable because such a wide quiet zone is unnecessary in many
        applications where the QR code is not being printed.

        Example:
            >>> code = pyqrcode.create('Hello. Uhh, can we have your liver?')
            >>> code.svg('live-organ-transplants.svg', 3.6)
            >>> code.svg('live-organ-transplants.svg', scale=4,
                         module_color='brown', background='0xFFFFFF')
        """
        builder._svg(self.code, self.version, file, scale=scale,
                     module_color=module_color, background=background,
                     quiet_zone=quiet_zone, xmldecl=xmldecl, svgns=svgns,
                     title=title, svgclass=svgclass, lineclass=lineclass,
                     omithw=omithw, debug=debug)

    def eps(self, file, scale=1, module_color=(0, 0, 0),
            background=None, quiet_zone=4):
        """This method writes the QR code out as an EPS document. The
        code is drawn by only writing the data modules corresponding to a 1.
        They are drawn using a line, such that contiguous modules in a row
        are drawn with a single line.

        The *file* parameter is used to specify where to write the document
        to. It can either be a writable (text) stream or a file path.

        The *scale* parameter sets how large to draw a single module. By
        default one point (1/72 inch) is used to draw a single module. This may
        make the code to small to be read efficiently. Increasing the scale
        will make the code larger. This method will accept fractional scales
        (e.g. 2.5).

        The *module_color* parameter sets the color of the data modules. The
        *background* parameter sets the background (page) color to use. They
        are specified as either a triple of floats, e.g. (0.5, 0.5, 0.5), or a
        triple of integers, e.g. (128, 128, 128). The default *module_color* is
        black. The default *background* color is no background at all.

        The *quiet_zone* parameter sets how large to draw the border around
        the code. As per the standard, the default value is 4 modules.

        Examples:
            >>> qr = pyqrcode.create('Hello world')
            >>> qr.eps('hello-world.eps', scale=2.5, module_color='#36C')
            >>> qr.eps('hello-world2.eps', background='#eee')
            >>> out = io.StringIO()
            >>> qr.eps(out, module_color=(.4, .4, .4))
        """
        builder._eps(self.code, self.version, file, scale, module_color,
                     background, quiet_zone)

    def terminal(self, module_color='default', background='reverse',
                 quiet_zone=4):
        """This method returns a string containing ASCII escape codes,
        such that if printed to a compatible terminal, it will display
        a vaild QR code. The code is printed using ASCII escape
        codes that alter the coloring of the background.

        The *module_color* parameter sets what color to
        use for the data modules (the black part on most QR codes).
        Likewise, the *background* parameter sets what color to use
        for the background (the white part on most QR codes).

        There are two options for colors. The first, and most widely
        supported, is to use the 8 or 16 color scheme. This scheme uses
        eight to sixteen named colors. The following colors are
        supported the most widely supported: black, red, green,
        yellow, blue, magenta, and cyan. There are an some additional
        named colors that are supported by most terminals: light gray,
        dark gray, light red, light green, light blue, light yellow,
        light magenta, light cyan, and white.

        There are two special named colors. The first is the
        "default" color. This color is the color the background of
        the terminal is set to. The next color is the "reverse"
        color. This is not really a color at all but a special
        property that will reverse the current color. These two colors
        are the default values for *module_color* and *background*
        respectively. These values should work on most terminals.

        Finally, there is one more way to specify the color. Some
        terminals support 256 colors. The actual colors displayed in the
        terminal is system dependent. This is the least transportable option.
        To use the 256 color scheme set *module_color* and/or
        *background* to a number between 0 and 256.

        The *quiet_zone* parameter sets how wide the quiet zone around the code
        should be. According to the standard this should be 4 modules. It is
        left settable because such a wide quiet zone is unnecessary in many
        applications.

        Example:
            >>> code = pyqrcode.create('Example')
            >>> text = code.terminal()
            >>> print(text)
        """
        return builder._terminal(self.code, module_color, background,
                                 quiet_zone)

    def text(self, quiet_zone=4):
        """This method returns a string based representation of the QR code.
        The data modules are represented by 1's and the background modules are
        represented by 0's. The main purpose of this method is to allow a user
        to write their own renderer.

        The *quiet_zone* parameter sets how wide the quiet zone around the code
        should be. According to the standard this should be 4 modules. It is
        left settable because such a wide quiet zone is unnecessary in many
        applications.

        Example:
            >>> code = pyqrcode.create('Example')
            >>> text = code.text()
            >>> print(text)
        """
        return builder._text(self.code, quiet_zone)
