# -*- coding: utf-8 -*-

"""   
This file contains global functions for formatting and printing data. This file
should be imported into individual log-parsing scripts located in the default
logparse.parsers module or in the user-supplied parsers directory. Data is
formatted in HTML or plaintext. Writing to disk and/or emailng data is left to
interface.py.
"""

import os
import re
import locale
from string import Template
from math import floor, ceil
from tabulate import tabulate
import textwrap

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

import logging
logger = None
logger = logging.getLogger(__name__)


locale.setlocale(locale.LC_ALL, '') # inherit system locale


DEG = u'\N{DEGREE SIGN}'
CEL = "C"
TIMEFMT = "%X"
DATEFMT = "%x"
CORNERCHARS_DOUBLE = ['╚', '╝', '╗', '╔']
CORNERCHARS_SINGLE = ['└', '┘', '┐', '┌']
LINECHARS_DOUBLE = ['║', '═']
LINECHARS_SINGLE = ['│', '─']
JXNCHARS_DOUBLE = ['╠', '╣', '╦', '╩', '╬']
JXNCHARS_SINGLE = ['├', '┤', '┬', '┴', '┼']
BULLET = "• "
INDENT = "  "
SPLIT_CHARS = ['.', '(', ')', '[', ']', '&', r"/", "\\", ',', '-', '_']


global VARSUBST


def init_var():
    """
    Initialise variable substitution templates (should be called before doing
    any substitutions)
    """

    global VARSUBST
    css_path = config.prefs.get("html", "css")
    if config.prefs.getboolean("html", "css-relpath"):
        if interface.argparser.parse_args().no_write:
            css_path = os.path.relpath(css_path, ".")
        elif interface.argparser.parse_args().destination:
            css_path = os.path.relpath(
                    css_path, interface.argparser.parse_args().destination())
        elif config.prefs.get("logparse", "output"):
            css_path = os.path.relpath(
                    css_path, config.prefs.get("logparse", "output"))
    VARSUBST = {
        "title": config.prefs.get("logparse", "title"),
        "date": interface.start.strftime(DATEFMT),
        "time": interface.start.strftime(TIMEFMT),
        "hostname": util.hostname(config.prefs.get(
            "logparse", "hostname-path")),
        "version": logparse.__version__,
        "css": css_path,
        "period": util.LogPeriod("logparse").startdate.strftime(
            TIMEFMT + " " + DATEFMT)
    }


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))

    def print_stdout(self, lines=False):
        """
        Echo the contents to the console
        """

        print()
        if lines:
            line = PlaintextLine(linewidth=
                    config.prefs.getint("plain", "linewidth"), double=True)
            print(line.draw())
        print(self.content)
        if lines:
            print(line.draw())
        print()


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
        """
        box = PlaintextBox(content=
                Template("$title $version on $hostname\n\n$time $date"
                    "\nParsing logs since $period")
                .safe_substitute(VARSUBST),
                vpadding=2, hpadding="\t\t", linewidth=self.linewidth)
        self.append(box.draw() + "\n"*2)

    def append_footer(self):
        """
        Append a horizontal line and some details
        """
        self.append(PlaintextLine(self.linewidth).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().
        """

        if section == None:
            logger.warning("Received null section")
            return
        self.append(PlaintextBox(
            content=section.title, double=False,
            fullwidth=False, vpadding=0, hpadding=" ").draw())
        if section.period and section.period.unique:
            self.append("\n(since {0})".format(
                section.period.startdate.strftime(DATEFMT + " " + TIMEFMT)))
        self.append('\n'*2)
        for data in section.data:
            self.append(self._fmt_data(data.subtitle, data.items))
            self.append('\n')
        for table in section.tables:
            self.append(table.draw_plain())
        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

        logger.debug("Processing data {}".format(subtitle))

        if (data == None or len(data) == 0):
            # If no list items are provided, just print the subtitle
            return subtitle + "\n"
        elif (len(data) == 1):
            # If only one item is provided, print it inline with subtitle
            return self._wrap_datum("{}: {}".format(subtitle, data[0]),
                    bullet=False, indent=False) + "\n"
        else:
            # If many items are provided, print them all as a bulleted list
            itemoutput = subtitle + ":\n"
            for datum in data:
                itemoutput += self._wrap_datum(datum) + "\n"
            return itemoutput

    def _wrap_datum(self, text, bullet=True, indent=True):
        """
        Use cpython's textwrap module to limit line width to the value 
        specified in self.linewidth. This is much easier than doing it all
        from scratch (which I tried to do originally). Note that line 
        continuations are automatically indented even if they don't have a 
        bullet. This is to make it clear which lines are continuations.
        """

        wrapper = textwrap.TextWrapper(
                initial_indent=(INDENT if indent else "") \
                        + (BULLET if bullet else ""),
                subsequent_indent=INDENT + (' '*len(BULLET) if bullet else ""),
                width=self.linewidth,
                replace_whitespace=True)

        return wrapper.fill(text)


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

    def __init__(self):
        """
        Initialise variables (no parameters required for initialisation)
        """

        self.content = ""
        self.destination = ""
        self.css = ""
        self._embedded = ""

    def embed_css(self, css):
        """
        Convert stylesheet to inline tags
        """

        if not self._embedded:
            self._embedded = mail.mailprep(re.sub(
                ".*" + re.escape(VARSUBST['css']) + ".*\n", "", self.content),
                css)
        return self._embedded

    def write_embedded(self, destination = ""):
        """
        Write contents to file with inline CSS tags
        """

        logger.debug("Writing HTML with embedded styles to " + destination)
        if not self._embedded:
            logger.warning("Call to write_embedded before embed_css - \
                    embedding stylesheets immediately")
            self.embed_css(config.prefs.get("html", "css"))
        if destination == "":
            destination = self.destination
        if destination == "":
            logger.warning("No destination path provided")
            return 1
        with open(destination, 'w') as f:
            f.write(self._embedded)
            logger.info("Written output to {}".format(destination))


    def append_header(self, template):
        """
        Insert variables into header template file and append HTML tags
        """

        self.headertemplate = template
        headercontent = Template(open(template, 'r').read())
        self.append(headercontent.safe_substitute(VARSUBST))
        self.append(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(closetag('div') + closetag('body') + 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().
        """

        if section == None:
            logger.warning("Received null section")
            return
        self.append(opentag('div', 1, section.title, 'section'))
        self.append(self._gen_title(section.title))
        if section.period and section.period.unique:
            self.append(self._fmt_period(section.period))
        for data in section.data:
            self.append(self._fmt_data(data.subtitle, data.items, data.severity))
        for table in section.tables:
            self.append(table.draw_html())
        self.append(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 tag('h2', False, title)

    def _fmt_data(self, subtitle, data=None, severity=0):
        """
        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 tag('p', False, subtitle, cl="severity-" + str(severity))
        else:
            logger.debug("Received data {}: {}".format(subtitle, data))
            subtitle += ':'
            if (len(data) == 1):
                return tag('p', False, subtitle + ' ' + data[0],
                        cl="severity-" + str(severity))
            else:
                output = ""
                output += tag('p', False, subtitle,
                        cl="severity-" + str(severity))
                output += 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 += tag('li', False, datum)
                output += closetag('ul', True)
                return output

    def _fmt_period(self, period):
        output = ''
        output += opentag('span', cl='period')
        output += "since " + period.startdate.strftime(DATEFMT + " " + TIMEFMT)
        output += closetag('span')
        return output

    def print_stdout_embedded(self, lines=False):
        """
        Echo the version with embedded style tags to the console
        """

        if self._embedded == "":
            self.embed_css(config.prefs.get("html", "css"))
        print()
        if lines:
            line = PlaintextLine(linewidth=
                    config.prefs.getint("plain", "linewidth"), double=True)
            print(line.draw())
        print(self._embedded)
        if lines:
            print(line.draw())
        print()


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

    def __init__(self, title, period=None):
        self.title = title
        self.data = []
        self.tables = []
        self.period = util.LogPeriod(self.title)

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

    def append_table(self, table):
        self.tables.append(table)


class Data:
    """
    Each section (parser) can have one or more Data() objects which are
    essentially glorified lists with titles (`self.subtitle`).
    """
    
    def __init__(self, subtitle="", items=[], severity=0):
        """
        Initialise variables. No parameters are enforced upon initialisation,
        but at least the subtitle is required for valid output. Severity refers
        to the importance of the data (integer from 0 to 5). e.g. a failed
        system should have severity 5 and will be formatted appropriately by
        the Output object.
        """

        self.subtitle = subtitle
        self.items = items 
        self.severity = severity

    def truncl(self, limit):      # truncate list
        """
        Truncate self.items to a specified value and state how many items are
        hidden. Set limit to -1 to avoid truncating any items.
        """

        if limit == -1:
            return self
        if (len(self.items) > limit):
            more = len(self.items) - limit
            if more == 1:
                return 0
            self.items = self.items[:limit]
            self.items.append("+ {0} more".format(str(more)))
        return self

    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))]
        return self


class Table(object):
    """
    A wrapper for python-tabulate's Tabulate type.
    """
    
    def __init__(self, double=False, borders=False, hpadding=" ",
            maxwidth=80, headers=[]):
        """
        Initialise variables. Note the keymap is used for a faster index map,
        but is not currently used anywhere (may be removed in future).
        """

        self.rows =  []     # List of row objects
        self.keymap = {}    # For fast lookup of row by value of first column 
        self.double = double
        self.borders = borders
        self.align_cols = []
        self.hpadding = hpadding
        self.maxwidth = maxwidth
        self.headers = headers
        self._align_cols = []

    def add_row(self, row):
        """
        Append a row to the list and amend index mapping
        """

        self.rows.append(row)
        if len(row.columns) > 0:
            self.keymap[row.columns[0]] = row

        logger.debug("Added row with {0} columns".format(str(len(row.columns))))

    def align_column(self, i, align):
        """
        Set alignment for the 'i'th column (`align` should be 'l', 'c' or 'r')
        """

        while len(self._align_cols) -1 < i:
            self._align_cols.append("")
        self._align_cols[i] = align
        for row in self.rows:
            row.columns[i].align = align
        logger.debug("Column alignment is now {0}".format(self._align_cols))

    def _gen_list(self):
        """
        Used locally for organising rows and columns into a 2D list structure
        """

        hierarchy = []
        for row in self.rows:
            row_data = []
            for column in row.columns:
                row_data.append(column.content)
            hierarchy.append(row_data)
        return hierarchy

    def draw_html(self):
        """
        Output HTML string (wrapper for tabulate)
        """

        output = tabulate(self._gen_list(), self.headers, tablefmt="html",
                colalign=tuple(self._align_cols))
        return output

    def draw_plain(self):
        """
        Output plain text string (wrapper for tabulate)
        """

        output = tabulate(self._gen_list(), self.headers,
                tablefmt="fancy_grid" if self.borders
                else "plain", colalign=tuple(self._align_cols))
        return output + "\n"*2


class Row(object):
    """
    Object representing a literal row in a 2D table with the individual cells
    in the row represented by columns[].
    """
    
    def __init__(self, columns=[], header=False):
        """
        Initialise variables. The variable n is used locally to keep track of
        the row width.
        """

        self.columns = columns
        self.header = header
        self.n = len(self.columns)

    def add_column(self, column):
        """
        Append a single cell horizontally and increment the cell count
        """

        self.columns.append(column)
        self.n += 1

    def rm_column(self, column):
        """
        Remove the specified column object and decrement the cell count
        """

        self.remove(column)
        self.n -= 1


class Column(object):
    """
    Object representing a single table cell. "Column" is somewhat of a misnomer 
    - one column object exists for each cell in the table. Columns are children
    of rows.
    """

    def __init__(self, content="", align="right"):
        """
        Initialise variables. The align property sets the alignment of a single
        cell ('l', 'c', or 'r').
        """

        self.content = content
        self.align = align


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

    def __init__(self, linewidth=80, double=True, vpadding=0, hpadding=""):
        """
        Initialise variables
        """

        self.linewidth = linewidth
        self.double = double
        self.vpadding = vpadding
        self.hpadding = hpadding

    def draw(self):
        """
        Output a plain text string based on the current object parameters
        """

        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 + 1)


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):
        """
        Initialise variables
        """
        self.content = content
        self.fullwidth = fullwidth
        self.linewidth = linewidth
        self.hpadding = hpadding 
        self.vpadding = vpadding
        self.double = double

    def draw(self):
        """
        Output a plain text string based on the current object parameters. This
        involves calculating the text width, breaking text at the maximum line
        length, and then drawing a box around it all.
        """

        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("Content width 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 backticks(l):
    """
    Surround every item in a list by backticks. Used for showing code in both
    HTML and plain text formats (converted to <code> tags for HTML)
    """

    return ["`" + x + "`" for x in l]


def plural(noun, quantity, print_quantity=True):
    """
    Return "1 noun" or "n nouns"
    """

    if (quantity == 1):
        if print_quantity:
            return(str(quantity) + " " + noun)
        else:
            return noun
    else:
        if noun.endswith("s"):
            noun += "e"
        if print_quantity:
            return(str(quantity) + " " + noun + "s")
        else:
            return 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(subject):
    """
    Replace variables in the title template provided in config
    """

    r = Template(subject).safe_substitute(VARSUBST)
    logger.debug("Returning subject line " + r)
    return r


def opentag(tag, block=False, id=None, cl=None, style=None):
    """
    Write HTML opening tag
    """

    output = ""
    if block:
        output += '\n'
    output += '<' + tag
    if id:
        output += " id='" + id + "'"
    if cl:
        output += " class='" + cl + "'"
    if style:
        output += " style='"
        output += " ".join("{0}: {1};".format(attr, value)
                for attr, value in style.items())
        output += "'"
    output += '>'
    if block:
        output += '\n'
    return output


def closetag(tag, block=False):
    """
    Write HTML closing tag
    """

    if block:
        return "\n</" + tag + ">\n"
    else:
        return "</" + tag + ">"


def tag(tag, block=False, content="", id=None, cl=None, style=None):
    """
    Write HTML opening tag, content, and closing tag
    """

    o = opentag(tag, block, id, cl, style)
    c = closetag(tag, block)
    return o + content + c