from __future__ import annotations

import json
from functools import lru_cache
from pathlib import Path

from .models import PortingBacklog, PortingModule

SNAPSHOT_PATH = Path(__file__).resolve().parent / 'reference_data' / 'commands_snapshot.json'


@lru_cache(maxsize=1)
def load_command_snapshot() -> tuple[PortingModule, ...]:
    raw_entries = json.loads(SNAPSHOT_PATH.read_text())
    return tuple(
        PortingModule(
            name=entry['name'],
            responsibility=entry['responsibility'],
            source_hint=entry['source_hint'],
            status='mirrored',
        )
        for entry in raw_entries
    )


PORTED_COMMANDS = load_command_snapshot()


def build_command_backlog() -> PortingBacklog:
    return PortingBacklog(title='Command surface', modules=list(PORTED_COMMANDS))


def command_names() -> list[str]:
    return [module.name for module in PORTED_COMMANDS]


def get_command(name: str) -> PortingModule | None:
    needle = name.lower()
    for module in PORTED_COMMANDS:
        if module.name.lower() == needle:
            return module
    return None


def find_commands(query: str, limit: int = 20) -> list[PortingModule]:
    needle = query.lower()
    matches = [module for module in PORTED_COMMANDS if needle in module.name.lower() or needle in module.source_hint.lower()]
    return matches[:limit]


def render_command_index(limit: int = 20, query: str | None = None) -> str:
    modules = find_commands(query, limit) if query else list(PORTED_COMMANDS[:limit])
    lines = [f'Command entries: {len(PORTED_COMMANDS)}', '']
    if query:
        lines.append(f'Filtered by: {query}')
        lines.append('')
    lines.extend(f'- {module.name} — {module.source_hint}' for module in modules)
    return '\n'.join(lines)