"""
    isort.py

    Exposes a simple library to sort through imports within Python code

    usage:
        SortImports(file_name)
    or:
        sorted = SortImports(file_contents=file_contents).output

    Copyright (C) 2013  Timothy Edmund Crosley

    Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
    documentation files (the "Software"), to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and
    to permit persons to whom the Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in all copies or
    substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
    TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
    CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
    OTHER DEALINGS IN THE SOFTWARE.
"""

from __future__ import absolute_import, division, print_function, unicode_literals

import codecs
import copy
import os
import os.path
from collections import namedtuple
from sys import path as PYTHONPATH
from sys import stderr, stdout

from natsort import natsorted
from pies import *

from . import settings

Sections = ("FUTURE", "STDLIB", "THIRDPARTY", "FIRSTPARTY", "LOCALFOLDER")
Sections = namedtuple('Sections', Sections)(*range(len(Sections)))


class SortImports(object):
    config = settings.default

    def __init__(self, file_path=None, file_contents=None, write_to_stdout=False, check=False, **setting_overrides):
        self.write_to_stdout = write_to_stdout
        if setting_overrides:
            self.config = settings.default.copy()
            self.config.update(setting_overrides)

        file_name = file_path
        if file_path:
            file_path = os.path.abspath(file_path)
            if "/" in file_name:
                file_name = file_name[file_name.rfind('/') + 1:]
            if file_name in self.config['skip']:
                print("WARNING: {0} was skipped as it's listed in 'skip' setting".format(file_path), file=stderr)
                file_contents = None
            else:
                self.file_path = file_path
                with open(file_path) as file_to_import_sort:
                    file_contents = file_to_import_sort.read()
                    if sys.version < '3':
                        file_contents = file_contents.decode('utf8')

        if file_contents is None or ("isort:" + "skip_file") in file_contents:
            return

        self.in_lines = file_contents.split("\n")
        self.original_length = len(self.in_lines)
        for add_import in self.config['add_imports']:
            self.in_lines.append(add_import)
        self.number_of_lines = len(self.in_lines)

        self.out_lines = []
        self.imports = {}
        self.as_map = {}
        for section in Sections:
            self.imports[section] = {'straight': set(), 'from': {}}

        self.index = 0
        self.import_index = -1
        self._parse()
        if self.import_index != -1:
            self._add_formatted_imports()

        self.length_change = len(self.out_lines) - self.original_length
        while self.out_lines and self.out_lines[-1].strip() == "":
            self.out_lines.pop(-1)
        self.out_lines.append("")

        if check:
            if self.out_lines == self.in_lines:
                print("SUCCESS: {0} Everything Looks Good!".format(self.file_path))
            else:
                print("ERROR: {0} Imports are incorrectly sorted.".format(self.file_path), file=stderr)
            return
        self.output = "\n".join(self.out_lines)
        if self.write_to_stdout:
            stdout.write(self.output)
        elif file_name:
            with codecs.open(self.file_path, encoding='utf-8', mode='w') as output_file:
                output_file.write(self.output)

    def place_module(self, moduleName):
        """Tries to determine if a module is a python std import,
           third party import, or project code:
           if it can't determine - it assumes it is project code
        """
        if moduleName.startswith("."):
            return Sections.LOCALFOLDER

        index = moduleName.find('.')
        if index:
            firstPart = moduleName[:index]
        else:
            firstPart = None

        if moduleName == "__future__" or (firstPart == "__future__"):
            return Sections.FUTURE
        elif moduleName in self.config['known_standard_library'] or \
                (firstPart in self.config['known_standard_library']):
            return Sections.STDLIB
        elif moduleName in self.config['known_third_party'] or (firstPart in self.config['known_third_party']):
            return Sections.THIRDPARTY
        elif moduleName in self.config['known_first_party'] or (firstPart in self.config['known_first_party']):
            return Sections.FIRSTPARTY

        for prefix in PYTHONPATH:
            module_path = "/".join((prefix, moduleName.replace(".", "/")))
            package_path = "/".join((prefix, moduleName.split(".")[0]))
            if (os.path.exists(module_path + ".py") or os.path.exists(module_path + ".so") or
               (os.path.exists(package_path) and os.path.isdir(package_path))):
                if "site-packages" in prefix or "dist-packages" in prefix:
                    return Sections.THIRDPARTY
                elif "python2" in prefix.lower() or "python3" in prefix.lower():
                    return Sections.STDLIB
                else:
                    return Sections.FIRSTPARTY

        return Sections.FIRSTPARTY

    def _get_line(self):
        """ Returns the current line from the file while
            incrementing the index
        """
        line = self.in_lines[self.index]
        self.index += 1
        return line

    @staticmethod
    def _import_type(line):
        """ If the current line is an import line it will
            return its type (from or straight)
        """
        if "isort:skip" in line:
            return
        elif line.startswith('import '):
            return "straight"
        elif line.startswith('from ') and "import" in line:
            return "from"

    def _at_end(self):
        """ returns True if we are at the end of the file """
        return self.index == self.number_of_lines

    @staticmethod
    def _module_key(module_name, config):
        module_name = str(module_name).lower()
        return "{0}{1}".format(module_name in config['force_to_top'] and "A" or "B",
                               config['length_sort'] and (str(len(module_name)) + ":" + module_name) or module_name)

    def _add_formatted_imports(self):
        """ Adds the imports back to the file
            (at the index of the first import)
            sorted alphabetically and split between groups
        """
        output = []
        for section in Sections:
            straight_modules = list(self.imports[section]['straight'])
            straight_modules = natsorted(straight_modules, key=lambda key: self._module_key(key, self.config))

            for module in straight_modules:
                if module in self.config['remove_imports']:
                    continue

                if module in self.as_map:
                    output.append("import {0} as {1}".format(module, self.as_map[module]))
                else:
                    output.append("import {0}".format(module))

            from_modules = list(self.imports[section]['from'].keys())
            from_modules = natsorted(from_modules, key=lambda key: self._module_key(key, self.config))
            for module in from_modules:
                if module in self.config['remove_imports']:
                    continue

                import_start = "from {0} import ".format(module)
                from_imports = list(self.imports[section]['from'][module])
                from_imports = natsorted(from_imports, key=lambda key: self._module_key(key, self.config))
                if self.config['remove_imports']:
                    from_imports = [line for line in from_imports if not "{0}.{1}".format(module, line) in
                                    self.config['remove_imports']]

                for from_import in copy.copy(from_imports):
                    import_as = self.as_map.get(module + "." + from_import, False)
                    if import_as:
                        output.append(import_start + "{0} as {1}".format(from_import, import_as))
                        from_imports.remove(from_import)

                if from_imports:
                    if "*" in from_imports:
                        import_statement = "{0}*".format(import_start)
                    else:
                        import_statement = import_start + (", ").join(from_imports)
                        if len(import_statement) > self.config['line_length'] and len(from_imports) > 1:
                            output_mode = settings.WrapModes._fields[self.config.get('multi_line_output', 0)].lower()
                            formatter = getattr(self, "_output_" + output_mode, self._output_grid)
                            import_statement = formatter(import_start, from_imports, " " * (len(import_start) + 1),
                                                         self.config['indent'], self.config['line_length'])

                    output.append(import_statement)

            if straight_modules or from_modules:
                output.append("")

        while [character.strip() for character in output[-1:]] == [""]:
            output.pop()

        self.out_lines[self.import_index:0] = output

        imports_tail = self.import_index + len(output)
        while [character.strip() for character in self.out_lines[imports_tail: imports_tail + 1]] == [""]:
            self.out_lines.pop(imports_tail)

        if len(self.out_lines) > imports_tail:
            next_construct = self.out_lines[imports_tail]
            if next_construct.startswith("def") or next_construct.startswith("class") or \
               next_construct.startswith("@"):
                self.out_lines[imports_tail:0] = ["", ""]
            else:
                self.out_lines[imports_tail:0] = [""]

    @staticmethod
    def _output_grid(statement, imports, white_space, indent, line_length):
        statement += "(" + imports.pop(0)
        while imports:
            next_import = imports.pop(0)
            next_statement = statement + ", " + next_import
            if len(next_statement.split("\n")[-1]) + 1 > line_length:
                next_statement = "{0},\n{1}{2}".format(statement, white_space, next_import)
            statement = next_statement
        return statement + ")"

    @staticmethod
    def _output_vertical(statement, imports, white_space, indent, line_length):
        return "{0}({1})".format(statement, (",\n" + white_space).join(imports))

    @staticmethod
    def _output_hanging_indent(statement, imports, white_space, indent, line_length):
        statement += " " + imports.pop(0)
        while imports:
            next_import = imports.pop(0)
            next_statement = statement + ", " + next_import
            if len(next_statement.split("\n")[-1]) + 3 > line_length:
                next_statement = "{0}, \\\n{1}{2}".format(statement, indent, next_import)
            statement = next_statement
        return statement

    @staticmethod
    def _output_vertical_hanging_indent(statement, imports, white_space, indent, line_length):
        return "{0}(\n{1}{2}\n)".format(statement, indent, (",\n" + indent).join(imports))

    @staticmethod
    def _output_vertical_grid_common(statement, imports, white_space, indent, line_length):
        statement += "(\n" + indent + imports.pop(0)
        while imports:
            next_import = imports.pop(0)
            next_statement = "{0}, {1}".format(statement, next_import)
            if len(next_statement.split("\n")[-1]) + 1 > line_length:
                next_statement = "{0},\n{1}{2}".format(statement, indent, next_import)
            statement = next_statement
        return statement

    @classmethod
    def _output_vertical_grid(cls, statement, imports, white_space, indent, line_length):
        return cls._output_vertical_grid_common(statement, imports, white_space, indent, line_length) + ")"

    @classmethod
    def _output_vertical_grid_grouped(cls, statement, imports, white_space, indent, line_length):
        return cls._output_vertical_grid_common(statement, imports, white_space, indent, line_length) + "\n)"

    @staticmethod
    def _strip_comments(line):
        """
            Removes comments from import line.
        """
        comment_start = line.find("#")
        if comment_start != -1:
            print("Removing comment(%s) so imports can be sorted correctly" % line[comment_start:], file=stderr)
            line = line[:comment_start]

        return line

    def _parse(self):
        """
            Parses a python file taking out and categorizing imports
        """
        while not self._at_end():
            line = self._get_line()
            import_type = self._import_type(line)
            if not import_type:
                self.out_lines.append(line)
                continue

            if self.import_index == -1:
                self.import_index = self.index - 1

            import_string = self._strip_comments(line)
            if "(" in line and not self._at_end():
                while not line.strip().endswith(")") and not self._at_end():
                    line = self._strip_comments(self._get_line())
                    import_string += "\n" + line
            else:
                while line.strip().endswith("\\"):
                    line = self._strip_comments(self._get_line())
                    import_string += "\n" + line

            import_string = import_string.replace("_import", "[[i]]")
            for remove_syntax in ['\\', '(', ')', ",", 'from ', 'import ']:
                import_string = import_string.replace(remove_syntax, " ")
            import_string = import_string.replace("[[i]]", "_import")

            imports = import_string.split()
            if "as" in imports and (imports.index('as') + 1) < len(imports):
                while "as" in imports:
                    index = imports.index('as')
                    if import_type == "from":
                        self.as_map[imports[0] + "." + imports[index - 1]] = imports[index + 1]
                    else:
                        self.as_map[imports[index - 1]] = imports[index + 1]
                    del imports[index:index + 2]
            if import_type == "from":
                import_from = imports.pop(0)
                root = self.imports[self.place_module(import_from)][import_type]
                if root.get(import_from, False):
                    root[import_from].update(imports)
                else:
                    root[import_from] = set(imports)
            else:
                for module in imports:
                    self.imports[self.place_module(module)][import_type].add(module)
