# Copyright (c) 2017-2026 Juancarlo Añez (apalala@gmail.com)
# SPDX-License-Identifier: BSD-4-Clause

from __future__ import annotations

import re
import textwrap

from .. import grammars, ngcodegen
from ..exceptions import CodegenError
from ..objectmodel import Node
from ..util import indent, safe_name, timestamp, trim
from ..util.abctools import compress_seq
from ..util.deprecate import deprecated
from .cgbase import CodeGenerator, ModelRenderer


@deprecated(replacement=ngcodegen.codegen)
def codegen(model):
    return PythonCodeGenerator().render(model)


class PythonCodeGenerator(CodeGenerator):
    def _find_renderer_class(self, node):
        if not isinstance(node, Node):
            return None

        name = node.__class__.__name__
        renderer = globals().get(name)
        if not renderer or not issubclass(renderer, Base):
            raise CodegenError(f'Renderer for {name} not found')
        return renderer


class Base(ModelRenderer):
    def defines(self):
        return self.node.defines()

    def make_defines_declaration(self):
        defines = compress_seq(self.defines())
        ldefs = {safe_name(d) for d, value in defines if value}
        sdefs = {safe_name(d) for d, value in defines if not value and d not in ldefs}

        if not (sdefs or ldefs):
            return ''
        else:
            sdefs = '[{}]'.format(', '.join(sorted(repr(d) for d in sdefs)))
            ldefs = '[{}]'.format(', '.join(sorted(repr(d) for d in ldefs)))
            if not ldefs:
                return f'\n\n    self._define({sdefs}, {ldefs})'
            else:
                return '\n' + trim(self.define_template % (sdefs, ldefs))

    define_template = """\
            self._define(
                %s,
                %s,
            )\
        """


class Void(Base):
    template = 'self._void()'


class Dot(Base):
    template = 'self._dot()'


class Fail(Base):
    template = 'self._fail()'


class Comment(Base):
    def render_fields(self, fields):
        lines = '\n'.join(f'# {c!s}' for c in self.node.comment.splitlines())
        fields.update(lines=lines)

    template = '\n{lines}\n'


class EOLComment(Comment):
    pass


class EOF(Base):
    template = 'self._check_eof()'


class _Decorator(Base):
    template = '{exp}'


class Group(_Decorator):
    template = """\
                with self._group():
                {exp:1::}\
                """


class Token(Base):
    def render_fields(self, fields):
        fields.update(token=repr(self.node.token))

    template = 'self._token({token})'


class Constant(Base):
    def render_fields(self, fields):
        fields.update(constant=repr(self.node.literal))

    template = 'self._constant({constant})'


class Alert(Base):
    def render_fields(self, fields):
        fields.update(literal=repr(self.node.literal), level=self.node.level)

    template = 'self._alert({literal}, {level})'


class Pattern(Base):
    def render_fields(self, fields):
        raw_repr = repr(self.node.pattern)
        fields.update(pattern=raw_repr)

    template = 'self._pattern({pattern})'


class Lookahead(_Decorator):
    template = """\
                with self._if():
                {exp:1::}\
                """


class NegativeLookahead(_Decorator):
    template = """\
                with self._ifnot():
                {exp:1::}\
                """


class Sequence(Base):
    def render_fields(self, fields):
        fields.update(seq='\n'.join(self.rend(s) for s in self.node.sequence))
        defines = self.make_defines_declaration()
        fields.update(defines=defines)

    template = """{seq}
                {defines}\
                """


class Choice(Base):
    def render_fields(self, fields):
        firstset = self.node.lookahead_str()
        if firstset:
            msglines = textwrap.wrap(firstset, width=40)
            error = ['expecting one of: ', *msglines]
        else:
            error = ['no available options']
        error = [repr(e) for e in error]
        fields.update(n=self.counter(), error=error)
        fields.update(options='\n'.join(self.rend(o) for o in self.node.options))

    def render(self, **fields):
        if len(self.node.options) == 1:
            return self.rend(self.options[0], **fields)
        else:
            return super().render(**fields)

    template = """\
                with self._choice():
                {options:1::}
                    raise self.newexcept(
                {error:2:\\n:}  # noqa: COM812
                    ) from None\
                """


class Option(_Decorator):
    def render_fields(self, fields):
        defines = self.make_defines_declaration()
        fields.update(defines=defines)

    template = """\
                with self._option():
                {exp:1::}\
                """


class Closure(_Decorator):
    def render_fields(self, fields):
        fields.update(n=self.counter())

    def render(self, **fields):
        if () in self.node.exp.lookahead():
            raise CodegenError(f'{self.node} may repeat empty sequence')
        return '\n' + super().render(**fields)

    template = """\
                def block{n}():
                {exp:1::}
                self._closure(block{n})\
                """


class PositiveClosure(Closure):
    template = """\
                def block{n}():
                {exp:1::}
                self._positive_closure(block{n})\
                """


class Join(_Decorator):
    def render_fields(self, fields):
        fields.update(n=self.counter())

    def render(self, **fields):
        if () in self.node.exp.lookahead():
            raise CodegenError('may repeat empty sequence')
        return '\n' + super().render(**fields)

    template = """\
                def sep{n}():
                {sep:1::}

                def block{n}():
                {exp:1::}
                self._join(block{n}, sep{n})\
                """


class PositiveJoin(Join):
    template = """\
                def sep{n}():
                {sep:1::}

                def block{n}():
                {exp:1::}
                self._positive_join(block{n}, sep{n})\
                """


class Gather(Join):
    template = """\
                def sep{n}():
                {sep:1::}

                def block{n}():
                {exp:1::}
                self._gather(block{n}, sep{n})\
                """


class PositiveGather(Join):
    template = """\
                def sep{n}():
                {sep:1::}

                def block{n}():
                {exp:1::}
                self._positive_gather(block{n}, sep{n})\
                """


class LeftJoin(PositiveJoin):
    template = """\
                def sep{n}():
                {sep:1::}

                def block{n}():
                {exp:1::}
                self._left_join(block{n}, sep{n})\
                """


class RightJoin(PositiveJoin):
    template = """\
                def sep{n}():
                {sep:1::}

                def block{n}():
                {exp:1::}
                self._right_join(block{n}, sep{n})\
                """


class EmptyClosure(Base):
    template = 'self._empty_closure()'


class SkipTo(Closure):
    template = """\
                def block{n}():
                {exp:1::}
                self._skip_to(block{n})\
    """


class Optional(_Decorator):
    template = """\
                with self._optional():
                {exp:1::}\
                """


class Cut(Base):
    template = 'self._cut()'


class Named(_Decorator):
    def __str__(self):
        return f'{self.name}:{self.rend(self.exp)}'

    def render_fields(self, fields):
        fields.update(n=self.counter(), name=safe_name(self.node.name))

    template = """
                {exp}
                self.setname('{name}')\
                """


class NamedList(Named):
    template = """
                {exp}
                self.addname('{name}')\
                """


class Override(Named):
    pass


class OverrideList(NamedList):
    pass


class Call(Base):
    template = 'self._{name}_()'


class RuleInclude(_Decorator):
    def render_fields(self, fields):
        super().render_fields(fields)
        fields.update(exp=self.rend(self.node.ruleinfo.exp))

    template = """
                {exp}
                """


class Rule(_Decorator):
    @staticmethod
    def param_repr(p):
        if isinstance(p, int | float):
            return str(p)
        else:
            return repr(p.split('::')[0])

    def render(self, **fields):
        try:
            return super().render(**fields)
        except CodegenError as e:
            raise CodegenError(f'{self.node.name}={e}') from e

    def render_fields(self, fields):
        self.reset_counter()

        params = kwparams = ''
        if self.node.params:
            params = ', '.join(self.param_repr(self.rend(p)) for p in self.node.params)
        if self.node.kwparams:
            kwparams = ', '.join(
                f'{k}={self.param_repr(self.rend(v))}' for k, v in self.kwparams.items()
            )

        if params and kwparams:
            params = params + ', ' + kwparams
        elif kwparams:
            params = kwparams

        fields.update(params=params)

        sdefines = ''
        if not isinstance(self.node, grammars.Choice):
            sdefines = self.make_defines_declaration()
        fields.update(defines=sdefines)
        leftrec = self.node.is_leftrec
        fields.update(leftrec='\n@leftrec' if leftrec else '')
        fields.update(
            nomemo='\n@nomemo' if not self.node.is_memoizable and not leftrec else '',
        )
        fields.update(isname='\n@isname' if self.node.is_name else '')

    template = """
        @rule({params})\
        {leftrec}\
        {nomemo}\
        {isname}
        def _{name}_(self):
        {exp:1::}
        """

    define_template = """\
            self._define(
                %s,
                %s
            )\
        """


class BasedRule(Rule):
    def defines(self):
        return self.rhs.defines()

    def render_fields(self, fields):
        super().render_fields(fields)
        fields.update(exp=self.rhs)


class Grammar(Base):
    def render_fields(self, fields):
        abstract_template = trim(self.abstract_rule_template)
        abstract_rules = [
            abstract_template.format(name=safe_name(rule.name))
            for rule in self.node.rulemap
        ]
        abstract_rules = indent('\n'.join(abstract_rules))

        whitespace = self.node.config.whitespace
        if not whitespace:
            whitespace = 'None'
        elif isinstance(whitespace, re.Pattern):
            whitespace = repr(whitespace)
        else:
            whitespace = f're.compile(r"{whitespace}")'

        if self.node.config.nameguard is not None:
            nameguard = repr(self.node.config.nameguard)
        else:
            nameguard = 'None'

        ignorecase = self.node.config.ignorecase
        left_recursion = self.node.config.left_recursion
        parseinfo = self.node.config.parseinfo
        namechars = repr(self.node.config.namechars or '')
        comments = repr(self.node.config.comments)
        eol_comments = repr(self.node.config.eol_comments)

        rules = '\n'.join(
            [self.get_renderer(rule).render() for rule in self.node.rulemap],
        )

        version = str(tuple(int(n) for n in str(timestamp()).split('.')))

        keywords = [str(k) for k in self.keywords if k is not None]
        keywords = '\n'.join(f'    {k!r},' for k in keywords)
        if keywords:
            keywords = f'(\n{keywords}\n)'

        fields.update(
            rules=indent(rules),
            start=self.node.rulemap[0].name,
            abstract_rules=abstract_rules,
            version=version,
            whitespace=whitespace,
            nameguard=nameguard,
            ignorecase=ignorecase,
            left_recursion=left_recursion,
            parseinfo=parseinfo,
            keywords=keywords,
            namechars=namechars,
            comments=comments,
            eol_comments=eol_comments,
        )

    abstract_rule_template = """
            def {name}(self, ast):
                return ast
            """

    template = """\
                #!/usr/bin/env python3

                # CAVEAT UTILITOR
                #
                # This file was automatically generated by TatSu.
                #
                #    https://pypi.python.org/pypi/tatsu/
                #
                # Any changes you make to it will be overwritten the next time
                # the file is generated.

                # ruff: noqa: RUF100, C405, COM812, I001, F401, PLR1702, PLC2801, SIM117
                # ruff: noqa: PL2401, PLC2402, PLC2403

                import sys
                from pathlib import Path

                from tatsu.buffering import Buffer
                from tatsu.parsing import Parser
                from tatsu.parsing import rule
                from tatsu.parsing import isname, generic_main, leftrec, nomemo
                from tatsu.infos import ParserConfig


                KEYWORDS: set[str] = set({keywords})


                class {name}Buffer(Buffer):
                    def __init__(self, text, /, config: ParserConfig | None = None, **settings):
                        config = ParserConfig.new(
                            config,
                            whitespace={whitespace},
                            nameguard={nameguard},
                            ignorecase={ignorecase},
                            namechars={namechars},
                            parseinfo={parseinfo},
                            comments={comments},
                            eol_comments={eol_comments},
                            keywords=KEYWORDS,
                            start={start!r},
                        )
                        config = config.override(**settings)
                        super().__init__(text, config=config)


                class {name}Parser(Parser):
                    def __init__(self, /, config: ParserConfig | None = None, **settings):
                        config = ParserConfig.new(
                            config,
                            whitespace={whitespace},
                            nameguard={nameguard},
                            ignorecase={ignorecase},
                            namechars={namechars},
                            parseinfo={parseinfo},
                            comments={comments},
                            eol_comments={eol_comments},
                            left_recursion={left_recursion},
                            keywords=KEYWORDS,
                            start={start!r},
                        )
                        config = config.override(**settings)
                        super().__init__(config=config)

                {rules}


                class {name}Semantics:
                {abstract_rules}


                def main(filename, **kwargs):
                    if not filename or filename == '-':
                        text = sys.stdin.read()
                    else:
                        text = Path(filename).read_text()
                    parser = {name}Parser()
                    return parser.parse(
                        text,
                        filename=filename,
                        **kwargs,
                    )


                if __name__ == '__main__':
                    import json
                    from tatsu.util import asjson

                    ast = generic_main(main, {name}Parser, name='{name}')
                    data = asjson(ast)
                    print(json.dumps(data, indent=2))
                """