# -*- coding: utf-8 -*-
"""
Provides utility function for generating Sphinx-based documentation.
"""

from __future__ import absolute_import
import codecs
from behave.textutil import compute_words_maxsize, text as _text
import six


# -----------------------------------------------------------------------------
# SPHINX OUTPUT GENERATION FUNCTIONS:
# -----------------------------------------------------------------------------
class DocumentWriter(object):
    """
    Provides a simple "ReStructured Text Writer" to generate
    Sphinx-based documentation.
    """
    heading_styles = ["=", "=", "-", "~"]
    default_encoding = "utf-8"
    default_toctree_title = "**Contents:**"

    def __init__(self, stream, filename=None, should_close=True):
        self.stream = stream
        self.filename = filename
        self.should_close = should_close

    @classmethod
    def open(cls, filename, encoding=None):
        encoding = encoding or cls.default_encoding
        stream = codecs.open(filename, "wb", encoding)
        return cls(stream, filename)

    def write(self, *args):
        return self.stream.write(*args)

    def close(self):
        if self.stream and self.should_close:
            self.stream.close()
        self.stream = None

    def write_heading(self, heading, level=0, index_id=None, label=None):
        assert self.stream
        assert heading, "Heading should not be empty"
        assert 0 <= level < len(self.heading_styles)
        if level >= len(self.heading_styles):
            level = len(self.heading_styles) - 1
        heading_size = len(heading)
        heading_style = self.heading_styles[level]
        if level == 0 and heading_size < 70:
            heading_size = 70
        separator = heading_style * heading_size
        if index_id:
            if isinstance(index_id, (list, tuple)):
                index_id = ", ".join(index_id)
            self.stream.write(".. index:: %s\n\n" % index_id)
        if label:
            self.stream.write(".. _%s:\n\n" % label)
        if level == 0:
            self.stream.write("%s\n" % separator)
        self.stream.write("%s\n" % heading)
        self.stream.write("%s\n" % separator)
        self.stream.write("\n")

    def write_toctree(self, entries, title=None, maxdepth=2):
        if title is None:
            title = self.default_toctree_title
        line_prefix = " " * 4
        if title:
            self.stream.write("%s\n\n" % title)
        self.stream.write(".. toctree::\n")
        self.stream.write("%s:maxdepth: %d\n\n" % (line_prefix, maxdepth))
        for entry in entries:
            self.stream.write("%s%s\n" % (line_prefix, entry))
        self.stream.write("\n")

    def write_table(self, table):
        """
        Write a ReST simple table.

        EXAMPLE:
        ========================================= ===== ===== ===== =====
        Step Definition                           Given When  Then  Step
        ========================================= ===== ===== ===== =====
        Given a file named "{filename}" contains
        Then the file "{filename}" should ...
        ========================================= ===== ===== ===== =====

        :param table:   Table to render (as `behave.model.Table`)

        .. todo::
            Column alignments
        """
        assert self.stream

        # -- STEP: Determine table layout dimensions
        cols_size = []
        separator_parts = []
        row_schema_parts = []
        for col_index, heading in enumerate(table.headings):
            column = [six.text_type(row[col_index]) for row in table.rows]
            column.append(heading)
            column_size = compute_words_maxsize(column)
            cols_size.append(column_size)
            separator_parts.append("=" * column_size)
            row_schema_parts.append("%-" + _text(column_size) + "s")

        separator = " ".join(separator_parts) + "\n"
        row_schema = " ".join(row_schema_parts) + "\n"
        self.stream.write("\n")     # -- ENSURE: Empty line before table start.
        self.stream.write(separator)
        self.stream.write(row_schema % tuple(table.headings))
        self.stream.write(separator)
        for row in table.rows:
            self.stream.write(row_schema % tuple(row))
        self.stream.write(separator)
        self.stream.write("\n")     # -- ENSURE: Empty line after table end.