from pathlib import Path
from typing import Iterable

from docforge.models import Project, Module, DocObject


class MCPRenderer:
    """
    Renderer that emits documentation as MCP resources.
    """

    name = "mcp"

    def generate_sources(self, project: Project, out_dir: Path) -> None:
        """
        Generate MCP-compatible resources for the project.

        Each module is rendered as a standalone MCP document.
        """
        out_dir.mkdir(parents=True, exist_ok=True)

        for module in project.get_all_modules():
            self._write_module(module, out_dir)

    def _write_module(self, module: Module, out_dir: Path) -> None:
        """
        Render a module and all contained objects.
        """
        resource_path = self._module_resource_path(module)
        content = self._render_module(module)

        file_path = out_dir / resource_path
        file_path.parent.mkdir(parents=True, exist_ok=True)
        file_path.write_text(content, encoding="utf-8")

    def _render_module(self, module: Module) -> str:
        """
        Render a module into MCP-friendly Markdown.
        """
        lines: list[str] = []

        lines.append(f"# Module `{module.path}`\n")

        if module.docstring:
            lines.append(module.docstring.strip() + "\n")

        for obj in module.get_all_objects():
            lines.extend(self._render_object(obj, level=2))

        return "\n".join(lines).strip() + "\n"

    def _render_object(self, obj: DocObject, level: int) -> Iterable[str]:
        """
        Recursively render DocObjects.
        """
        prefix = "#" * level
        lines: list[str] = []

        lines.append(f"{prefix} {obj.kind} `{obj.name}`")

        if obj.signature:
            lines.append(f"```python\n{obj.signature}\n```")

        if obj.docstring:
            lines.append(obj.docstring.strip())

        for member in obj.get_all_members():
            lines.extend(self._render_object(member, level + 1))

        return lines

    def _module_resource_path(self, module: Module) -> Path:
        """
        Convert a module path into an MCP resource path.
        Example:
            docforge.models.module -> docforge/models/module.md
        """
        return Path(module.path.replace(".", "/") + ".md")