#
#   format.py
#   
#   This file contains global functions for formatting and printing data. This
#   file should be imported into individual log-parsing scripts located in
#   logs/*. Data is formatted in HTML or plaintext. Writing to disk and/or
#   emailng data is left to __main__.py.
#

import os
import re
import locale
from string import Template

import logparse
from . import interface, util, config, mail

import logging
logger = logging.getLogger(__name__)


locale.setlocale(locale.LC_ALL, '') # inherit system locale
#DEG = "°".encode('unicode_escape')
DEG = u'\N{DEGREE SIGN}'
CEL = "C"
TIMEFMT = "%X"
DATEFMT = "%x"
CORNERCHARS_DOUBLE = ['╚', '╝', '╗', '╔']
CORNERCHARS_SINGLE = ['└', '┘', '┐', '┌']
LINECHARS_DOUBLE = ['║', '═']
LINECHARS_SINGLE = ['│', '─']
BULLET = "• "
INDENT = "  "


class Output:
    """
    Base class for a data processor. 
    """
    
    def __init__(self):
        self.content = ""
        self.destination = ""

    def append(self, content):
        """
        Add a string
        """
        self.content += content

    def write(self, destination=""):
        """
        Output contents into a file
        """
        if destination == "":
            destination = self.destination
        if destination == "":
            logger.warning("No destination path provided")
            return 1
        with open(destination, 'w') as f:
            f.write(self.content)
            logger.info("Written output to {}".format(destination))


class PlaintextOutput(Output):
    """
    Processes & outputs data in a plaintext form which can be read with cat or plaintext email.
    """

    def __init__(self, linewidth=80):
        self.content = ""
        self.destination = ""
        self.linewidth = linewidth;

    def append_header(self, template=''):
        """
        Print details with some primitive formatting
        """
        init_varfilter()
        box = PlaintextBox(content=Template("$title $version on $hostname\n\n$time $date").safe_substitute(varsubst), vpadding=2, hpadding="\t\t", linewidth=config.prefs['linewidth'])
        line = PlaintextLine(self.linewidth)
        self.append(box.draw() + line.draw())

    def append_footer(self):
        """
        Append a horizontal line and some details
        """
        init_varfilter()
        self.append(PlaintextLine(self.linewidth, vpadding=1).draw())
        self.append(Template("$hostname $time $date").safe_substitute(varsubst))

    def append_section(self, section):
        """
        Call the appropriate methods to format a section (provided by a parser).
        This should be run by interface.py after every instance of parse_log().
        """
        self.append(PlaintextBox(content=section.title, double=False, fullwidth=False, vpadding=0, hpadding=" ").draw())
        self.append('\n'*2)
        for data in section.data:
            self.append(self._fmt_data(data.subtitle, data.items))
            self.append('\n')

    def _fmt_data(self, subtitle, data = None):   # write title and data
        """
        Format the properties of a data object into usable plaintext form with a few fancy symbols/formatting tricks.
        Subtitle is required, data is not. If only subtitle is supplied or subtitle + one data item, a single line will be printed.
        """
        if (subtitle == ""):
            logger.warning("No subtitle provided.. skipping section")
            return

        if (data == None or len(data) == 0):
            logger.debug("No data provided.. just printing subtitle")
            return subtitle + '\n'
        else:
            logger.debug("Received data " + str(data))
            subtitle += ':'
            if (len(data) == 1):
                return subtitle + ' ' + data[0] + '\n'
            else:
                itemoutput = subtitle + '\n'
                for datum in data:
                    datum = BULLET + datum
                    if len(datum) > config.prefs['linewidth'] - 3:
                        words = datum.split()
                        if max(map(len, words)) > config.prefs['linewidth'] - len(INDENT):
                            continue
                        res, part, others = [], words[0], words[1:]
                        for word in others:
                            if 1 + len(word) > config.prefs['linewidth'] - len(part):
                                res.append(part)
                                part = word
                            else:
                                part += ' ' + word
                        if part:
                            res.append(part)
                        datum = ('\n    ').join(res)
                    datum = INDENT + datum
                    itemoutput += datum + '\n'
                return itemoutput


class HtmlOutput(Output):
    """
    Process and output data in HTML format.
    All HTML formatting functions now reside in this class to differentiate them from plaintext.
    """

    def __init__(self):
        self.content = ""
        self.destination = ""
        self.css = ""

    def embed_css(self, css):
        """
        Convert stylesheet to inline tags
        """
        self.content = mail.mailprep(self.content, css)
        return self.content

    def append_header(self, template):
        """
        Insert variables into header template file and append HTML tags
        """
        init_varfilter()
        headercontent = Template(open(template, 'r').read())
        self.append(headercontent.safe_substitute(varsubst))
        self.append(self.opentag('div', id='main'))

    def append_footer(self):
        """
        Close HTML tags that were opened in the template.
        TODO: add footer template similar to header template.
        """
        self.append(self.closetag('div') + self.closetag('body') + self.closetag('html'))

    def append_section(self, section):
        """
        Call the appropriate methods to generate HTML tags for a section (provided by a parser).
        This should be run by interface.py after every instance of parse_log().
        """
        self.append(self.opentag('div', 1, section.title, 'section'))
        self.append(self._gen_title(section.title))
        for data in section.data:
            self.append(self._fmt_data(data.subtitle, data.items))
        self.append(self.closetag('div', 1))

    def _gen_title(self, title):
        """
        Format the title for a section
        """
        if (title == '' or '\n' in title):
            logger.error("Invalid title")
            raise ValueError 
        logger.debug("Writing title for " + title)
        return self.tag('h2', False, title)

    def _fmt_data(self, subtitle, data = None):
        """
        Format the properties of a data object into usable HTML tags.
        Subtitle is required, data is not. If only subtitle is supplied or subtitle + one data item, a single line will be printed.
        """
        if (subtitle == ""):
            logger.warning("No subtitle provided.. skipping section")
            return

        if (data == None or len(data) == 0):
            logger.debug("No data provided.. just printing subtitle")
            return self.tag('p', False, subtitle)
        else:
            logger.debug("Received data " + str(data))
            subtitle += ':'
            if (len(data) == 1):
                return self.tag('p', False, subtitle + ' ' + data[0])
            else:
                output = ""
                output += self.tag('p', False, subtitle)
                output += self.opentag('ul', 1)
                coderegex = re.compile('`(.*)`')
                for datum in data:
                    if datum == "" or datum == None:
                        continue
                    datum = coderegex.sub(r"<code>\1</code>", str(datum))
                    output += self.tag('li', False, datum)
                output += self.closetag('ul', True)
                return output

    def opentag(self, tag, block=False, id=None, cl=None):
        """
        Write HTML opening tag
        """
        output = ""
        if (block):
            output += '\n'
        output += '<' + tag
        if (id != None):
            output += " id='" + id + "'"
        if (cl != None):
            output += " class='" + cl + "'"
        output += '>'
        if (block):
            output += '\n'
        return output

    def closetag(self, tag, block=False):
        """
        Write HTML closing tag
        """
        if block:
            return "\n</" + tag + ">\n"
        else:
            return "</" + tag + ">"

    def tag(self, tag, block=False, content=""):
        """
        Write HTML opening tag, content, and closing tag
        """
        o = self.opentag(tag, block)
        c = self.closetag(tag, block)
        return o + content + c


class Section:
    """
    Each parser should output a Section() which contains the title and returned data.
    """

    def __init__(self, title):
        self.title = title
        self.data = []

    def append_data(self, data):
        self.data.append(data)


class Data:
    """
    Each section (parser) can have one or more Data() objects which are essentially glorified lists.
    """
    
    def __init__(self, subtitle="", items=[]):
        self.subtitle = subtitle
        self.items = items 

    def truncl(self, limit):      # truncate list
        """
        Truncate self.items to a specified value and state how many items are hidden.
        """
        if (len(self.items) > limit):
            more = str(len(self.items) - limit)
            self.items = self.items[:limit]
            self.items.append("+ {0} more".format(more))

    def orderbyfreq(self):
        """
        Order a list by frequency of each item, then remove duplicates and append frequency in parentheses.
        """
        unsorted = list(self.items)
        self.items = ["{0} ({1})".format(y, unsorted.count(y)) for y in sorted(set(unsorted), key = lambda x: -unsorted.count(x))]


class PlaintextLine:
    """
    Draw a horizontal line for plain text format, with optional padding/styling.
    """

    def __init__(self, linewidth=80, double=True, vpadding=1, hpadding=""):
        self.linewidth = linewidth
        self.double = False
        self.vpadding = vpadding
        self.hpadding = hpadding

    def draw(self):
        line = (LINECHARS_DOUBLE[1] if self.double else LINECHARS_SINGLE[1])
        return "\n" * self.vpadding + self.hpadding +  line * (self.linewidth - 2 * len(self.hpadding)) + self.hpadding + "\n" * self.vpadding


class PlaintextBox:
    """
    Draw a rectangular box around text, with customisable padding/size/style
    """

    def __init__(self, content="", double=True, fullwidth=True, linewidth=80, hpadding="\t", vpadding=1):
        self.content = content
        self.fullwidth = fullwidth
        self.linewidth = linewidth
        self.hpadding = hpadding 
        self.vpadding = vpadding
        self.double = double

    def draw(self):

        if self.double == True:
            cornerchars = CORNERCHARS_DOUBLE
            linechars = LINECHARS_DOUBLE
        else:
            cornerchars = CORNERCHARS_SINGLE
            linechars = LINECHARS_SINGLE

        # Check hpadding has a definite width
        self.hpadding = self.hpadding.replace("\t", " "*4)

        # Calculate number of characters per line
        contentlines = self.content.splitlines()
        contentwidth = int((self.linewidth if self.linewidth > 0 else 80) if self.content.splitlines() else len(max(contentlines, key=len)))
        logger.debug("Contentwidth is {0}".format(str(contentwidth)))
        logger.debug("Longest line is {0}".format(len(max(contentlines, key=len))))
        contentwidth += -2*(len(self.hpadding)+1)
        if not self.fullwidth:
            longestline = len(max(contentlines, key=len))
            if longestline <= self.linewidth - 2*(len(self.hpadding)+1):
                contentwidth = longestline

        # Split lines that are too long
        for i, line in enumerate(contentlines):
            if len(line) > contentwidth:
                words = line.split()
                if max(map(len, words)) > contentwidth:
                    continue
                res, part, others = [], words[0], words[1:]
                for word in others:
                    if len(' ') + len(word) > contentwidth - len(part):
                        res.append(part)
                        part = word
                    else:
                        part += ' ' + word
                if part:
                    res.append(part)
                contentlines[i] = res

        # Flatten list
        #   Note list comprehension doesn't work here, so we must iterate through each item
        newlines = []
        for line in contentlines:
            if isinstance(line, list):
                for subline in line:
                    newlines.append(subline)
            else:
                newlines.append(line)
        contentlines = newlines
               
        # Add vertical padding
        for _ in range(self.vpadding):
            contentlines.insert(0, ' '*contentwidth)
            contentlines.append(' '*contentwidth)

        # Insert horizontal padding on lines that are too short
        contentlines = [linechars[0] + self.hpadding + x + ' '*(self.linewidth-(len(x)+2*len(self.hpadding)+2) if len(x) < contentwidth else 0) + self.hpadding + linechars[0] for x in contentlines]
        contentlines.insert(0, cornerchars[3] + linechars[1] * (contentwidth + len(self.hpadding)*2) + cornerchars[2])
        contentlines.append(cornerchars[0] + linechars[1] * (contentwidth + len(self.hpadding)*2) + cornerchars[1])
        return ('\n').join(contentlines)


def init_varfilter():
    global varfilter
    global varpattern
    global varsubst
    varfilter = {"$title$": config.prefs['title'], "$date$": interface.start.strftime(DATEFMT),"$time$": interface.start.strftime(TIMEFMT), "$hostname$": util.hostname(config.prefs['hostname-path']), "$version$": logparse.__version__, "$css$": os.path.relpath(config.prefs['css'], os.path.dirname(config.prefs['output']))}
    varfilter = dict((re.escape(k), v) for k, v in varfilter.items())
    varpattern = re.compile("|".join(varfilter.keys()))
    varsubst = dict(title=config.prefs['title'], date=interface.start.strftime(DATEFMT), time=interface.start.strftime(TIMEFMT), hostname=util.hostname(config.prefs['hostname-path']), version=logparse.__version__, css=os.path.relpath(config.prefs['css'], os.path.dirname(config.prefs['output'])))

def backticks(l):
    return ["`" + x + "`" for x in l]


def plural(noun, quantity):
    """
    Return "1 noun" or "n nouns"
    """
    if (quantity == 1):
        return(str(quantity) + " " + noun)
    else:
        return(str(quantity) + " " + noun + "s")


def parsesize(num, suffix='B'):
    """
    Return human-readable size from number of bytes
    """
    for unit in ['','Ki','Mi','Gi','Ti','Pi','Ei','Zi']:
        if abs(num) < 1024.0:
            return "%3.1f %s%s" % (num, unit, suffix)
        num /= 1024.0
    return "%.1f%s%s" % (num, 'Yi', suffix)


def fsubject(template):
    """
    Replace variables in the title template provided in config
    """
    r = varpattern.sub(lambda m: varfilter[re.escape(m.group(0))], template)
    logger.debug("Returning subject line " + r)
    return r