"""
registry.py - Discovery and registration for framework feature modules

Each package directly under ``modules`` may expose ``register(registry)``.
The same registry is loaded by the API, Discord bot, and scheduler so a
feature can keep its routes, commands, prompts, and jobs together.
"""

import importlib
import pkgutil


class FrameworkRegistry:
    def __init__(self):
        self.modules = {}
        self.commands = {}
        self.route_registrars = []
        self.job_handlers = {}
        self._loading_module = None

    def clear(self):
        self.modules.clear()
        self.commands.clear()
        self.route_registrars.clear()
        self.job_handlers.clear()
        self._loading_module = None

    def begin_module(self, name, package):
        if name in self.modules:
            raise ValueError(f"Duplicate module name: {name}")
        self.modules[name] = {
            "name": name,
            "package": package,
            "description": "",
        }
        self._loading_module = name

    def finish_module(self):
        self._loading_module = None

    def describe(self, description):
        module_name = self._require_loading_module()
        self.modules[module_name]["description"] = description.strip()

    def register_command(
        self,
        interaction_type,
        handler,
        prompt,
        validator=None,
        help_text=None,
        description="",
    ):
        module_name = self._require_loading_module()
        if interaction_type in self.commands:
            raise ValueError(f"Duplicate command type: {interaction_type}")
        if not callable(handler):
            raise TypeError(f"Handler for {interaction_type} must be callable")
        if validator is not None and not callable(validator):
            raise TypeError(f"Validator for {interaction_type} must be callable")
        if not isinstance(prompt, dict) or not prompt.get("system") or not prompt.get(
            "user_template"
        ):
            raise ValueError(
                f"Command {interaction_type} must provide system and user_template prompts"
            )

        self.commands[interaction_type] = {
            "module": module_name,
            "handler": handler,
            "prompt": prompt,
            "validator": validator,
            "help_text": list(help_text or []),
            "description": description.strip(),
        }

    def register_routes(self, registrar):
        module_name = self._require_loading_module()
        if not callable(registrar):
            raise TypeError(f"Route registrar for {module_name} must be callable")
        self.route_registrars.append((module_name, registrar))

    def register_job(self, job_type, handler):
        module_name = self._require_loading_module()
        if job_type in self.job_handlers:
            raise ValueError(f"Duplicate job type: {job_type}")
        if not callable(handler):
            raise TypeError(f"Job handler for {job_type} must be callable")
        self.job_handlers[job_type] = {
            "module": module_name,
            "handler": handler,
        }

    def get_command(self, interaction_type):
        return self.commands.get(interaction_type)

    def get_job_handler(self, job_type):
        registration = self.job_handlers.get(job_type)
        return registration["handler"] if registration else None

    def list_commands(self):
        return list(self.commands.keys())

    def router_context(self):
        lines = []
        for name, command in sorted(self.commands.items()):
            description = command["description"] or "No description provided"
            lines.append(f"- {name}: {description}")
        return "\n".join(lines) if lines else "No modules are available"

    def help_lines(self):
        lines = []
        for name, command in sorted(self.commands.items()):
            if command["help_text"]:
                lines.extend(f"- {item}" for item in command["help_text"])
            else:
                lines.append(f"- {name}: {command['description']}")
        return lines

    def _require_loading_module(self):
        if not self._loading_module:
            raise RuntimeError("Registration must happen inside a module register() call")
        return self._loading_module


registry = FrameworkRegistry()
_loaded = False


def discover_modules(force=False):
    """Discover and register feature packages exactly once per process."""
    global _loaded
    if _loaded and not force:
        return registry

    _loaded = False

    package = importlib.import_module("modules")
    discovered = sorted(
        item.name
        for item in pkgutil.iter_modules(package.__path__)
        if item.ispkg and not item.name.startswith("_")
    )

    registry.clear()
    try:
        for module_name in discovered:
            qualified_name = f"modules.{module_name}"
            feature_module = importlib.import_module(qualified_name)
            register_fn = getattr(feature_module, "register", None)
            if not callable(register_fn):
                raise RuntimeError(f"{qualified_name} must expose register(registry)")

            registry.begin_module(module_name, qualified_name)
            try:
                register_fn(registry)
            finally:
                registry.finish_module()
    except Exception:
        registry.clear()
        raise

    _loaded = True
    return registry


def reset_registry():
    """Reset discovery state for tests."""
    global _loaded
    registry.clear()
    _loaded = False