# some part of code are taken from
# https://github.com/prompt-toolkit/ptpython/blob/89017ba158ed1d95319233fa5aedf3931c3b8b77/ptpython/utils.py#L45
import inspect
import re
from dataclasses import dataclass

from core.sheerka.Sheerka import EXIT_COMMANDS
from core.sheerka.services.SheerkaFunctionsParametersHistory import SheerkaFunctionsParametersHistory
from core.tokenizer import Tokenizer, TokenKind, LexerError
from prompt_toolkit.completion import Completer, Completion

NAME = re.compile(r'[a-zA-Z0-9_\.]*[a-zA-Z_]')


@dataclass
class FuncFound:
    """
    Class used when inside a function
    """
    name: str  # name of the function
    index: int  # index in text
    paren_index: int  # index of the left parenthesis


@dataclass
class CompletionDesc:
    text: str
    display: str
    meta_display: str


class SheerkaPromptCompleter(Completer):

    def __init__(self, sheerka):
        self.sheerka = sheerka
        self.params_history_service = self.sheerka.services[SheerkaFunctionsParametersHistory.NAME]
        self.builtins = []
        for name, bound_method in sheerka.sheerka_methods.items():
            self.builtins.append(self.get_completion_desc(name, bound_method.method, "builtin", ["context"]))

        self.pipeable_builtins = []
        for name, pipeable in self.sheerka.sheerka_pipeables.items():
            self.pipeable_builtins.append(
                self.get_completion_desc(name, pipeable.method, "builtin", ["context", "iterable"]))

        self.exit_commands = [CompletionDesc(c, c, "command") for c in EXIT_COMMANDS]
        self.globals = {k: v.method for k, v in self.sheerka.sheerka_methods.items()}
        self.globals.update({k: v.method for k, v in self.sheerka.sheerka_pipeables.items()})

    def get_completions(self, document, complete_event):

        text = document.text_before_cursor

        if func_found := self.inside_function(document.text, document.cursor_position):
            param_number, comma_index = self.get_param_number(text[func_found.paren_index + 1:])
            values = self.params_history_service.get_function_parameters(func_found.name, param_number)
            as_custom_desc = [CompletionDesc(v, v, "history") for v in values]
            param_text = text[func_found.paren_index + comma_index + 2:].lstrip()
            yield from self.yield_completion_from_completion_desc(as_custom_desc, param_text)
            return

        if " " not in text:
            yield from self.yield_completion_from_completion_desc(self.exit_commands, text)
            yield from self.yield_completion_from_completion_desc(self.builtins, text)
            return

        if self.after_pipe(document.text, document.cursor_position):
            if document.char_before_cursor == " ":
                yield from self.yield_completion_from_completion_desc(self.pipeable_builtins, None)
            else:
                text = self.last_word(document.text, document.cursor_position)
                yield from self.yield_completion_from_completion_desc(self.pipeable_builtins, text)
            return

        yield from self.yield_completion_from_completion_desc(self.builtins, text)

    def get_completions_fom_jedi(self, document):
        script = self.get_jedi_script_from_document(document, self.globals, self.globals)
        if script:
            try:
                completions = script.complete()
            except TypeError:
                # Issue #9: bad syntax causes completions() to fail in jedi.
                # https://github.com/jonathanslenders/python-prompt-toolkit/issues/9
                pass
            except UnicodeDecodeError:
                # Issue #43: UnicodeDecodeError on OpenBSD
                # https://github.com/jonathanslenders/python-prompt-toolkit/issues/43
                pass
            except AttributeError:
                # Jedi issue #513: https://github.com/davidhalter/jedi/issues/513
                pass
            except ValueError:
                # Jedi issue: "ValueError: invalid \x escape"
                pass
            except KeyError:
                # Jedi issue: "KeyError: u'a_lambda'."
                # https://github.com/jonathanslenders/ptpython/issues/89
                pass
            except IOError:
                # Jedi issue: "IOError: No such file or directory."
                # https://github.com/jonathanslenders/ptpython/issues/71
                pass
            except AssertionError:
                # In jedi.parser.__init__.py: 227, in remove_last_newline,
                # the assertion "newline.value.endswith('\n')" can fail.
                pass
            except SystemError:
                # In jedi.api.helpers.py: 144, in get_stack_at_position
                # raise SystemError("This really shouldn't happen. There's a bug in Jedi.")
                pass
            except NotImplementedError:
                # See: https://github.com/jonathanslenders/ptpython/issues/223
                pass
            except Exception:
                # Supress all other Jedi exceptions.
                pass
            else:
                for c in completions:
                    yield Completion(
                        c.name_with_symbols,
                        len(c.complete) - len(c.name_with_symbols),
                        display=c.name_with_symbols,
                    )

    @staticmethod
    def yield_completion_from_completion_desc(definitions, text):
        for completion_desc in definitions:
            if text is None or text == "":
                yield Completion(completion_desc.text,
                                 0,
                                 display=completion_desc.display,
                                 display_meta=completion_desc.meta_display)
            elif completion_desc.text.startswith(text):
                yield Completion(completion_desc.text,
                                 -len(text),
                                 display=completion_desc.display,
                                 display_meta=completion_desc.meta_display)

    @staticmethod
    def get_completion_desc(name, function, meta_display, skip_params):

        function_name = name + "("
        signature = inspect.signature(function)
        params_count = len([p for p in signature.parameters if p not in skip_params])

        if params_count == 0:
            function_name += ")"
        return CompletionDesc(function_name, name, meta_display)

    @staticmethod
    def inside_function(text, pos):
        bracket_count = 0
        for i in range(pos)[::-1]:
            # look for an opening parenthesis that does not match a closing one
            if text[i] == "(":
                bracket_count += 1
            elif text[i] == ")":
                bracket_count -= 1

            if bracket_count > 0:
                break
        else:
            return None  # nothing found, return false

        paren_index = i

        while i > 1:
            # eat the whitespaces
            if text[i - 1] == " ":
                i -= 1
            else:
                break

        m = NAME.match(text[:i][::-1])
        if m:
            func_name = m.group(0)[::-1]
            return FuncFound(func_name, i - len(func_name), paren_index)

        return None

    @staticmethod
    def after_pipe(text, pos):
        for i in range(pos)[::-1]:
            if text[i] == "|":
                return True
        return False

    @staticmethod
    def last_word(text, pos, left_strip=True):
        if pos == 0:
            return ""

        start = pos - 1 if text[pos - 1] == " " else pos
        if start < 0:
            return ""

        for i in range(start)[::-1]:
            if text[i] == " ":
                return text[i:pos].lstrip() if left_strip else text[i:pos]

        return text[:pos].lstrip() if left_strip else text[:pos]

    @staticmethod
    def get_param_number(text):
        if text == "":
            return 0, -1

        tokens = Tokenizer(text)
        param_number = 0
        stop_counting = 0
        last_comma_index = -1
        try:
            for token in tokens:
                if token.type == TokenKind.COMMA and stop_counting == 0:
                    param_number += 1
                    last_comma_index = token.index
                if token.type == TokenKind.LPAR:
                    stop_counting += 1
                if token.type == TokenKind.RPAR:
                    stop_counting -= 1
        except LexerError:
            pass

        return param_number, last_comma_index

    @staticmethod
    def get_jedi_script_from_document(document, globals, locals):
        import jedi  # We keep this import in-line, to improve start-up time.

        # Importing Jedi is 'slow'.

        try:
            return jedi.Interpreter(
                document.text,
                column=document.cursor_position_col,
                line=document.cursor_position_row + 1,
                path="input-text",
                namespaces=[locals, globals],
            )
        except ValueError:
            # Invalid cursor position.
            # ValueError('`column` parameter is not in a valid range.')
            return None
        except AttributeError:
            # Workaround for #65: https://github.com/jonathanslenders/python-prompt-toolkit/issues/65
            # See also: https://github.com/davidhalter/jedi/issues/508
            return None
        except IndexError:
            # Workaround Jedi issue #514: for https://github.com/davidhalter/jedi/issues/514
            return None
        except KeyError:
            # Workaroud for a crash when the input is "u'", the start of a unicode string.
            return None
        except Exception:
            # Workaround for: https://github.com/jonathanslenders/ptpython/issues/91
            return None
    # def find_backwards(
    #     self,
    #     sub: str,
    #     in_current_line: bool = False,
    #     ignore_case: bool = False,
    #     count: int = 1,
    # ) -> Optional[int]:
    #     """
    #     Find `text` before the cursor, return position relative to the cursor
    #     position. Return `None` if nothing was found.
    #     :param count: Find the n-th occurrence.
    #     """
    #     if in_current_line:
    #         before_cursor = self.current_line_before_cursor[::-1]
    #     else:
    #         before_cursor = self.text_before_cursor[::-1]
    #
    #     flags = re.IGNORECASE if ignore_case else 0
    #     iterator = re.finditer(re.escape(sub[::-1]), before_cursor, flags)
    #
    #     try:
    #         for i, match in enumerate(iterator):
    #             if i + 1 == count:
    #                 return -match.start(0) - len(sub)
    #     except StopIteration:
    #         pass
    #     return None

    # def find(
    #     self,
    #     sub: str,
    #     in_current_line: bool = False,
    #     include_current_position: bool = False,
    #     ignore_case: bool = False,
    #     count: int = 1,
    # ) -> Optional[int]:
    #     """
    #     Find `text` after the cursor, return position relative to the cursor
    #     position. Return `None` if nothing was found.
    #     :param count: Find the n-th occurrence.
    #     """
    #     assert isinstance(ignore_case, bool)
    #
    #     if in_current_line:
    #         text = self.current_line_after_cursor
    #     else:
    #         text = self.text_after_cursor
    #
    #     if not include_current_position:
    #         if len(text) == 0:
    #             return None  # (Otherwise, we always get a match for the empty string.)
    #         else:
    #             text = text[1:]
    #
    #     flags = re.IGNORECASE if ignore_case else 0
    #     iterator = re.finditer(re.escape(sub), text, flags)
    #
    #     try:
    #         for i, match in enumerate(iterator):
    #             if i + 1 == count:
    #                 if include_current_position:
    #                     return match.start(0)
    #                 else:
    #                     return match.start(0) + 1
    #     except StopIteration:
    #         pass
    #     return None