# Copyright 2017 Palantir Technologies, Inc.
import io
import logging
import os
import re

import jedi

from . import lsp, uris, _utils

log = logging.getLogger(__name__)

# TODO: this is not the best e.g. we capture numbers
RE_START_WORD = re.compile('[A-Za-z_0-9]*$')
RE_END_WORD = re.compile('^[A-Za-z_0-9]*')


class Workspace(object):

    M_PUBLISH_DIAGNOSTICS = 'textDocument/publishDiagnostics'
    M_APPLY_EDIT = 'workspace/applyEdit'
    M_SHOW_MESSAGE = 'window/showMessage'

    def __init__(self, root_uri, endpoint):
        self._root_uri = root_uri
        self._endpoint = endpoint
        self._root_uri_scheme = uris.urlparse(self._root_uri)[0]
        self._root_path = uris.to_fs_path(self._root_uri)
        self._docs = {}

        # Whilst incubating, keep rope private
        self.__rope = None
        self.__rope_config = None

    def _rope_project_builder(self, rope_config):
        from rope.base.project import Project

        # TODO: we could keep track of dirty files and validate only those
        if self.__rope is None or self.__rope_config != rope_config:
            rope_folder = rope_config.get('ropeFolder')
            self.__rope = Project(self._root_path, ropefolder=rope_folder)
            self.__rope.prefs.set('extension_modules', rope_config.get('extensionModules', []))
            self.__rope.prefs.set('ignore_syntax_errors', True)
            self.__rope.prefs.set('ignore_bad_imports', True)
        self.__rope.validate()
        return self.__rope

    @property
    def documents(self):
        return self._docs

    @property
    def root_path(self):
        return self._root_path

    @property
    def root_uri(self):
        return self._root_uri

    def is_local(self):
        return (self._root_uri_scheme == '' or self._root_uri_scheme == 'file') and os.path.exists(self._root_path)

    def get_document(self, doc_uri):
        """Return a managed document if-present, else create one pointing at disk.

        See https://github.com/Microsoft/language-server-protocol/issues/177
        """
        return self._docs.get(doc_uri) or self._create_document(doc_uri)

    def put_document(self, doc_uri, source, version=None):
        self._docs[doc_uri] = self._create_document(doc_uri, source=source, version=version)

    def rm_document(self, doc_uri):
        self._docs.pop(doc_uri)

    def update_document(self, doc_uri, change, version=None):
        self._docs[doc_uri].apply_change(change)
        self._docs[doc_uri].version = version

    def apply_edit(self, edit):
        return self._endpoint.request(self.M_APPLY_EDIT, {'edit': edit})

    def publish_diagnostics(self, doc_uri, diagnostics):
        self._endpoint.notify(self.M_PUBLISH_DIAGNOSTICS, params={'uri': doc_uri, 'diagnostics': diagnostics})

    def show_message(self, message, msg_type=lsp.MessageType.Info):
        self._endpoint.notify(self.M_SHOW_MESSAGE, params={'type': msg_type, 'message': message})

    def source_roots(self, document_path):
        """Return the source roots for the given document."""
        files = _utils.find_parents(self._root_path, document_path, ['setup.py']) or []
        return [os.path.dirname(setup_py) for setup_py in files]

    def _create_document(self, doc_uri, source=None, version=None):
        path = uris.to_fs_path(doc_uri)
        return Document(
            doc_uri, source=source, version=version,
            extra_sys_path=self.source_roots(path),
            rope_project_builder=self._rope_project_builder,
        )


class Document(object):

    def __init__(self, uri, source=None, version=None, local=True, extra_sys_path=None, rope_project_builder=None):
        self.uri = uri
        self.version = version
        self.path = uris.to_fs_path(uri)
        self.filename = os.path.basename(self.path)

        self._local = local
        self._source = source
        self._extra_sys_path = extra_sys_path or []
        self._rope_project_builder = rope_project_builder

    def __str__(self):
        return str(self.uri)

    def _rope_resource(self, rope_config):
        from rope.base import libutils
        return libutils.path_to_resource(self._rope_project_builder(rope_config), self.path)

    @property
    def lines(self):
        return self.source.splitlines(True)

    @property
    def source(self):
        if self._source is None:
            with io.open(self.path, 'r', encoding='utf-8') as f:
                return f.read()
        return self._source

    def apply_change(self, change):
        """Apply a change to the document."""
        text = change['text']
        change_range = change.get('range')

        if not change_range:
            # The whole file has changed
            self._source = text
            return

        start_line = change_range['start']['line']
        start_col = change_range['start']['character']
        end_line = change_range['end']['line']
        end_col = change_range['end']['character']

        # Check for an edit occuring at the very end of the file
        if start_line == len(self.lines):
            self._source = self.source + text
            return

        new = io.StringIO()

        # Iterate over the existing document until we hit the edit range,
        # at which point we write the new text, then loop until we hit
        # the end of the range and continue writing.
        for i, line in enumerate(self.lines):
            if i < start_line:
                new.write(line)
                continue

            if i > end_line:
                new.write(line)
                continue

            if i == start_line:
                new.write(line[:start_col])
                new.write(text)

            if i == end_line:
                new.write(line[end_col:])

        self._source = new.getvalue()

    def offset_at_position(self, position):
        """Return the byte-offset pointed at by the given position."""
        return position['character'] + len(''.join(self.lines[:position['line']]))

    def word_at_position(self, position):
        """Get the word under the cursor returning the start and end positions."""
        if position['line'] >= len(self.lines):
            return ''

        line = self.lines[position['line']]
        i = position['character']
        # Split word in two
        start = line[:i]
        end = line[i:]

        # Take end of start and start of end to find word
        # These are guaranteed to match, even if they match the empty string
        m_start = RE_START_WORD.findall(start)
        m_end = RE_END_WORD.findall(end)

        return m_start[0] + m_end[-1]

    def jedi_names(self, all_scopes=False, definitions=True, references=False):
        return jedi.api.names(
            source=self.source, path=self.path, all_scopes=all_scopes,
            definitions=definitions, references=references
        )

    def jedi_script(self, position=None):
        kwargs = {
            'source': self.source,
            'path': self.path,
            'sys_path': self.sys_path()
        }
        if position:
            kwargs['line'] = position['line'] + 1
            kwargs['column'] = _utils.clip_column(position['character'], self.lines, position['line'])
        return jedi.Script(**kwargs)

    def sys_path(self):
        # Copy our extra sys path
        path = list(self._extra_sys_path)

        # TODO(gatesn): #339 - make better use of jedi environments, they seem pretty powerful
        environment = jedi.api.environment.get_cached_default_environment()
        path.extend(environment.get_sys_path())

        return path
