# based on https://github.com/ofosos/sphinxrecipes/blob/master/sphinxrecipes/sphinxrecipes.py

from __future__ import annotations

from docutils import nodes
from docutils.nodes import Node, Element
from docutils.parsers.rst import directives
from docutils.parsers.rst.states import Inliner
from sphinx.application import Sphinx
from sphinx.domains import Domain, Index
from sphinx.domains.std import StandardDomain
from sphinx.roles import XRefRole
from sphinx.directives import ObjectDescription
from sphinx.directives.code import container_wrapper
from sphinx.util.nodes import make_refnode
from sphinx import addnodes

class TocNode(ObjectDescription):
    def _object_hierarchy_parts(self, sig_node: addnodes.desc_signature) -> tuple[str, ...]:
        if 'fullname' not in sig_node:
            return ()

        modname = sig_node.get('module')
        fullname = sig_node['fullname']

        if modname:
            return (modname, *fullname.split('::'))
        else:
            return tuple(fullname.split('::'))

    def _toc_entry_name(self, sig_node: addnodes.desc_signature) -> str:
        if not sig_node.get('_toc_parts'):
            return ''

        config = self.env.app.config
        objtype = sig_node.parent.get('objtype')
        if config.add_function_parentheses and objtype in {'function', 'method'}:
            parens = '()'
        else:
            parens = ''
        *parents, name = sig_node['_toc_parts']
        if config.toc_object_entries_show_parents == 'domain':
            return sig_node.get('fullname', name) + parens
        if config.toc_object_entries_show_parents == 'hide':
            return name + parens
        if config.toc_object_entries_show_parents == 'all':
            return '.'.join(parents + [name + parens])
        return ''

class CommandNode(TocNode):
    """A custom node that describes a command."""

    name = 'cmd'
    required_arguments = 1

    option_spec = {
        'title': directives.unchanged,
        'tags': directives.unchanged
    }

    def handle_signature(self, sig, signode: addnodes.desc_signature):
        fullname = sig
        signode['fullname'] = fullname
        signode += addnodes.desc_addname(text="yosys> help ")
        signode += addnodes.desc_name(text=sig)
        return fullname

    def add_target_and_index(self, name_cls, sig, signode):
        signode['ids'].append(type(self).name + '-' + sig)
        if 'noindex' not in self.options:
            name = "{}.{}.{}".format(self.name, type(self).__name__, sig)
            tagmap = self.env.domaindata[type(self).name]['obj2tag']
            tagmap[name] = list(self.options.get('tags', '').split(' '))
            title = self.options.get('title', sig)
            titlemap = self.env.domaindata[type(self).name]['obj2title']
            titlemap[name] = title
            objs = self.env.domaindata[type(self).name]['objects']
            objs.append((name,
                         sig,
                         title,
                         self.env.docname,
                         type(self).name + '-' + sig,
                         0))

class CellNode(CommandNode):
    """A custom node that describes an internal cell."""

    name = 'cell'

class CellSourceNode(TocNode):
    """A custom code block for including cell source."""

    name = 'cellsource'

    option_spec = {
        "source": directives.unchanged_required,
        "language": directives.unchanged_required,
        'lineno-start': int,
    }

    def handle_signature(
        self,
        sig,
        signode: addnodes.desc_signature
    ) -> str:
        language = self.options.get('language')
        fullname = sig + "::" + language
        signode['fullname'] = fullname
        signode += addnodes.desc_name(text="Simulation model")
        signode += addnodes.desc_sig_space()
        signode += addnodes.desc_addname(text=f'({language})')
        return fullname
    
    def add_target_and_index(
        self,
        name: str,
        sig: str,
        signode: addnodes.desc_signature
    ) -> None:
        idx = f'{".".join(self.name.split(":"))}.{sig}'
        signode['ids'].append(idx)

    def run(self) -> list[Node]:
        """Override run to parse content as a code block"""
        if ':' in self.name:
            self.domain, self.objtype = self.name.split(':', 1)
        else:
            self.domain, self.objtype = '', self.name
        self.indexnode = addnodes.index(entries=[])

        node = addnodes.desc()
        node.document = self.state.document
        source, line = self.get_source_info()
        if line is not None:
            line -= 1
        self.state.document.note_source(source, line)
        node['domain'] = self.domain
        # 'desctype' is a backwards compatible attribute
        node['objtype'] = node['desctype'] = self.objtype
        node['noindex'] = noindex = ('noindex' in self.options)
        node['noindexentry'] = ('noindexentry' in self.options)
        node['nocontentsentry'] = ('nocontentsentry' in self.options)
        if self.domain:
            node['classes'].append(self.domain)
        node['classes'].append(node['objtype'])

        self.names = []
        signatures = self.get_signatures()
        for sig in signatures:
            # add a signature node for each signature in the current unit
            # and add a reference target for it
            signode = addnodes.desc_signature(sig, '')
            self.set_source_info(signode)
            node.append(signode)
            try:
                # name can also be a tuple, e.g. (classname, objname);
                # this is strictly domain-specific (i.e. no assumptions may
                # be made in this base class)
                name = self.handle_signature(sig, signode)
            except ValueError:
                # signature parsing failed
                signode.clear()
                signode += addnodes.desc_name(sig, sig)
                continue  # we don't want an index entry here
            finally:
                # Private attributes for ToC generation. Will be modified or removed
                # without notice.
                if self.env.app.config.toc_object_entries:
                    signode['_toc_parts'] = self._object_hierarchy_parts(signode)
                    signode['_toc_name'] = self._toc_entry_name(signode)
                else:
                    signode['_toc_parts'] = ()
                    signode['_toc_name'] = ''
            if name not in self.names:
                self.names.append(name)
                if not noindex:
                    # only add target and index entry if this is the first
                    # description of the object with this name in this desc block
                    self.add_target_and_index(name, sig, signode)
        
        # handle code
        code = '\n'.join(self.content)
        literal: Element = nodes.literal_block(code, code)
        if 'lineno-start' in self.options:
            literal['linenos'] = True
            literal['highlight_args'] = {
                'linenostart': self.options['lineno-start']
            }
        literal['classes'] += self.options.get('class', [])
        literal['language'] = self.options.get('language')
        literal = container_wrapper(self, literal, self.options.get('source'))

        return [self.indexnode, node, literal]

class TagIndex(Index):
    """A custom directive that creates a tag matrix."""
    
    name = 'tag'
    localname = 'Tag Index'
    shortname = 'Tag'
    
    def __init__(self, *args, **kwargs):
        super(TagIndex, self).__init__(*args, **kwargs)

    def generate(self, docnames=None):
        """Return entries for the index given by *name*.  If *docnames* is
        given, restrict to entries referring to these docnames.
        The return value is a tuple of ``(content, collapse)``, where
        * collapse* is a boolean that determines if sub-entries should
        start collapsed (for output formats that support collapsing
        sub-entries).
        *content* is a sequence of ``(letter, entries)`` tuples, where *letter*
        is the "heading" for the given *entries*, usually the starting letter.
        *entries* is a sequence of single entries, where a single entry is a
        sequence ``[name, subtype, docname, anchor, extra, qualifier, descr]``.
        The items in this sequence have the following meaning:
        - `name` -- the name of the index entry to be displayed
        - `subtype` -- sub-entry related type:
          0 -- normal entry
          1 -- entry with sub-entries
          2 -- sub-entry
        - `docname` -- docname where the entry is located
        - `anchor` -- anchor for the entry within `docname`
        - `extra` -- extra info for the entry
        - `qualifier` -- qualifier for the description
        - `descr` -- description for the entry
        Qualifier and description are not rendered e.g. in LaTeX output.
        """

        content = {}

        objs = {name: (dispname, typ, docname, anchor)
                for name, dispname, typ, docname, anchor, prio
                in self.domain.get_objects()}
        
        tmap = {}
        tags = self.domain.data['obj2tag']
        for name, tags in tags.items():
            for tag in tags:
                tmap.setdefault(tag,[])
                tmap[tag].append(name)
            
        for tag in tmap.keys():
            lis = content.setdefault(tag, [])
            objlis = tmap[tag]
            for objname in objlis:
                dispname, typ, docname, anchor = objs[objname]
                lis.append((
                    dispname, 0, docname,
                    anchor,
                    docname, '', typ
                ))
        re = [(k, v) for k, v in sorted(content.items())]

        return (re, True)


class CommandIndex(Index):    
    name = 'cmd'
    localname = 'Command Reference'
    shortname = 'Command'
    
    def __init__(self, *args, **kwargs):
        super(CommandIndex, self).__init__(*args, **kwargs)

    def generate(self, docnames=None):
        """Return entries for the index given by *name*.  If *docnames* is
        given, restrict to entries referring to these docnames.
        The return value is a tuple of ``(content, collapse)``, where
        * collapse* is a boolean that determines if sub-entries should
        start collapsed (for output formats that support collapsing
        sub-entries).
        *content* is a sequence of ``(letter, entries)`` tuples, where *letter*
        is the "heading" for the given *entries*, usually the starting letter.
        *entries* is a sequence of single entries, where a single entry is a
        sequence ``[name, subtype, docname, anchor, extra, qualifier, descr]``.
        The items in this sequence have the following meaning:
        - `name` -- the name of the index entry to be displayed
        - `subtype` -- sub-entry related type:
          0 -- normal entry
          1 -- entry with sub-entries
          2 -- sub-entry
        - `docname` -- docname where the entry is located
        - `anchor` -- anchor for the entry within `docname`
        - `extra` -- extra info for the entry
        - `qualifier` -- qualifier for the description
        - `descr` -- description for the entry
        Qualifier and description are not rendered e.g. in LaTeX output.
        """

        content = {}
        items = ((name, dispname, typ, docname, anchor)
                 for name, dispname, typ, docname, anchor, prio
                 in self.domain.get_objects())
        items = sorted(items, key=lambda item: item[0])
        for name, dispname, typ, docname, anchor in items:
            lis = content.setdefault(self.shortname, [])
            lis.append((
                dispname, 0, docname,
                anchor,
                '', '', typ
            ))
        re = [(k, v) for k, v in sorted(content.items())]

        return (re, True)

class CellIndex(CommandIndex):
    name = 'cell'
    localname = 'Internal cell reference'
    shortname = 'Internal cell'

class CommandDomain(Domain):
    name = 'cmd'
    label = 'Yosys commands'

    roles = {
        'ref': XRefRole()
    }

    directives = {
        'def': CommandNode,
    }

    indices = {
        CommandIndex,
        TagIndex
    }

    initial_data = {
        'objects': [],      # object list
        'obj2tag': {},      # name -> tags
        'obj2title': {},    # name -> title
    }

    def get_full_qualified_name(self, node):
        """Return full qualified name for a given node"""
        return "{}.{}.{}".format(type(self).name,
                                 type(node).__name__,
                                 node.arguments[0])

    def get_objects(self):
        for obj in self.data['objects']:
            yield(obj)

    def resolve_xref(self, env, fromdocname, builder, typ,
                     target, node, contnode):
        
        match = [(docname, anchor, name)
                 for name, sig, typ, docname, anchor, prio
                 in self.get_objects() if sig == target]

        if match:
            todocname = match[0][0]
            targ = match[0][1]
            qual_name = match[0][2]
            title = self.data['obj2title'].get(qual_name, targ)
            
            return make_refnode(builder,fromdocname,todocname,
                                targ, contnode, title)
        else:
            print(f"Missing ref for {target} in {fromdocname} ")
            return None
        
class CellDomain(CommandDomain):
    name = 'cell'
    label = 'Yosys internal cells'

    directives = {
        'def': CellNode,
        'source': CellSourceNode,
    }

    indices = {
        CellIndex,
        TagIndex
    }

def autoref(name, rawtext, text, lineno, inliner: Inliner,
            options=None, content=None):
    role = 'cell:ref' if text[0] == '$' else 'cmd:ref'
    return inliner.interpreted(rawtext, text, role, lineno)

def setup(app: Sphinx):
    app.add_domain(CommandDomain)
    app.add_domain(CellDomain)

    StandardDomain.initial_data['labels']['commandindex'] =\
        ('cmd-cmd', '', 'Command Reference')
    StandardDomain.initial_data['labels']['tagindex'] =\
        ('cmd-tag', '', 'Tag Index')
    StandardDomain.initial_data['labels']['cellindex'] =\
        ('cell-cell', '', 'Internal cell reference')
    StandardDomain.initial_data['labels']['tagindex'] =\
        ('cell-tag', '', 'Tag Index')

    StandardDomain.initial_data['anonlabels']['commandindex'] =\
        ('cmd-cmd', '')
    StandardDomain.initial_data['anonlabels']['tagindex'] =\
        ('cmd-tag', '')
    StandardDomain.initial_data['anonlabels']['cellindex'] =\
        ('cell-cell', '')
    StandardDomain.initial_data['anonlabels']['tagindex'] =\
        ('cell-tag', '')

    app.add_role('autoref', autoref)
    
    return {'version': '0.2'}