MyFastHtml/src/myfasthtml/controls/DslEditor.py

"""
DslEditor control - A CodeMirror wrapper for DSL editing.

Provides syntax highlighting, line numbers, and autocompletion
for domain-specific languages defined with Lark grammars.
"""

import json
import logging
from dataclasses import dataclass
from typing import Optional

from fasthtml.common import Script
from fasthtml.components import *

from myfasthtml.controls.BaseCommands import BaseCommands
from myfasthtml.controls.helpers import mk
from myfasthtml.core.commands import Command
from myfasthtml.core.dbmanager import DbObject
from myfasthtml.core.dsl.base import DSLDefinition
from myfasthtml.core.instances import MultipleInstance

logger = logging.getLogger("DslEditor")


@dataclass
class DslEditorConf:
  """Configuration for DslEditor."""
  name: str = None
  line_numbers: bool = True
  autocompletion: bool = True
  linting: bool = True
  placeholder: str = ""
  readonly: bool = False


class DslEditorState(DbObject):
  """Non-persisted state for DslEditor."""
  
  def __init__(self, owner, name, save_state):
    with self.initializing():
      super().__init__(owner, name=name, save_state=save_state)
      self.content: str = ""
      self.auto_save: bool = True


class Commands(BaseCommands):
  """Commands for DslEditor interactions."""
  
  def update_content(self):
    """Command to update content from CodeMirror."""
    return Command(
      "UpdateContent",
      "Update editor content",
      self._owner,
      self._owner.update_content,
    ).htmx(target=f"#{self._id}", swap="none")
  
  def toggle_auto_save(self):
    return Command("ToggleAutoSave",
                   "Toggle auto save",
                   self._owner,
                   self._owner.toggle_auto_save).htmx(target=f"#as_{self._id}", trigger="click")
  
  def save_content(self):
    return Command("SaveContent",
                   "Save content",
                   self._owner,
                   self._owner.save_content
                   ).htmx(target=None)


class DslEditor(MultipleInstance):
  """
  CodeMirror wrapper for editing DSL code.

  Provides:
  - Syntax highlighting based on DSL grammar
  - Line numbers
  - Autocompletion from grammar keywords/operators

  Args:
      parent: Parent instance.
      dsl: DSL definition providing grammar and completions.
      conf: Editor configuration.
      _id: Optional custom ID.
  """
  
  def __init__(
      self,
      parent,
      dsl: DSLDefinition,
      conf: Optional[DslEditorConf] = None,
      save_state: bool = True,
      _id: Optional[str] = None,
  ):
    super().__init__(parent, _id=_id)
    
    self._dsl = dsl
    self.conf = conf or DslEditorConf()
    self._state = DslEditorState(self, name=conf.name, save_state=save_state)
    self.commands = Commands(self)
    
    logger.debug(f"DslEditor created with id={self._id}, dsl={dsl.name}")
  
  def set_content(self, content: str):
    """Set the editor content programmatically."""
    self._state.content = content
    return self
  
  def get_content(self) -> str:
    """Get the current editor content."""
    return self._state.content
  
  def update_content(self, content: str = ""):
    """Handler for content update from CodeMirror."""
    self._state.content = content
    logger.debug(f"Content updated: {len(content)} chars")
    
    if self._state.auto_save:
      return None, self.on_content_changed()  # on_content_changed must be second to benefit from oob swap
    
    return None
  
  def save_content(self):
    logger.debug("save_content")
    return None, self.on_content_changed()  # on_content_changed must be second to benefit from oob swap
  
  def toggle_auto_save(self):
    logger.debug("toggle_auto_save")
    self._state.auto_save = not self._state.auto_save
    logger.debug(f"  auto_save={self._state.auto_save}")
    return self._mk_auto_save()
  
  def on_content_changed(self) -> None:
    pass
  
  def _get_editor_config(self) -> dict:
    """Build the JavaScript configuration object."""
    config = {
        "elementId": str(self._id),
        "textareaId": f"ta_{self._id}",
        "lineNumbers": self.conf.line_numbers,
        "autocompletion": self.conf.autocompletion,
        "linting": self.conf.linting,
        "placeholder": self.conf.placeholder,
        "readonly": self.conf.readonly,
        "updateCommandId": str(self.commands.update_content().id),
        "dslId": self._dsl.get_id(),
        "dsl": {
            "name": self._dsl.name,
            "completions": self._dsl.completions,
        },
    }
    return config
  
  def _mk_textarea(self):
    """Create the hidden textarea for form submission."""
    return Textarea(
      self._state.content,
      id=f"ta_{self._id}",
      name=f"ta_{self._id}",
      cls="hidden",
    )
  
  def _mk_editor_container(self):
    """Create the container where CodeMirror will be mounted."""
    return Div(
      id=f"cm_{self._id}",
      cls="mf-dsl-editor",
    )
  
  def _mk_init_script(self):
    """Create the initialization script."""
    config = self._get_editor_config()
    config_json = json.dumps(config)
    return Script(f"initDslEditor({config_json});")
  
  def _mk_auto_save(self):
    return Div(
      Label(
        mk.mk(
          Input(type="checkbox",
                checked="on" if self._state.auto_save else None,
                cls="toggle toggle-xs"),
          command=self.commands.toggle_auto_save()
        ),
        "Auto Save",
        cls="text-xs",
      ),
      mk.button("Save",
                cls="btn btn-xs btn-primary",
                disabled="disabled" if self._state.auto_save else None,
                command=self.commands.save_content()),
      cls="flex justify-between items-center p-2",
      id=f"as_{self._id}",
    ),
  
  def render(self):
    """Render the DslEditor component."""
    return Div(
      self._mk_auto_save(),
      self._mk_textarea(),
      self._mk_editor_container(),
      self._mk_init_script(),
      id=self._id,
      cls="mf-dsl-editor-wrapper",
    )
  
  def __ft__(self):
    """FastHTML magic method for rendering."""
    return self.render()