"""Agent router — selects the right subagent for each step."""

from __future__ import annotations

import logging

from ..models.agent import AgentRole
from ..models.session import TaskStep

logger = logging.getLogger(__name__)

# Keyword-based routing hints
_ROLE_KEYWORDS: dict[AgentRole, list[str]] = {
    AgentRole.COLLECTOR: [
        "gather", "collect", "read", "explore", "search", "find",
        "discover", "analyze", "investigate", "research", "scan",
        "understand", "review existing",
    ],
    AgentRole.CODER: [
        "implement", "write", "create", "build", "code", "fix",
        "modify", "refactor", "add", "update", "generate", "develop",
        "edit", "change", "configure", "set up",
    ],
    AgentRole.REVIEWER: [
        "review", "validate", "check", "verify", "test", "audit",
        "inspect", "evaluate", "assess", "confirm",
    ],
}


def route_step(step: TaskStep) -> AgentRole:
    """Determine which agent role should handle this step.

    Uses the step's declared agent_role if valid, otherwise falls back
    to keyword-based routing.
    """
    # Respect explicit assignment
    declared = step.agent_role.lower()
    try:
        role = AgentRole(declared)
        return role
    except ValueError:
        pass

    # Keyword-based fallback
    desc_lower = step.description.lower()
    scores: dict[AgentRole, int] = {role: 0 for role in _ROLE_KEYWORDS}

    for role, keywords in _ROLE_KEYWORDS.items():
        for kw in keywords:
            if kw in desc_lower:
                scores[role] += 1

    best = max(scores, key=lambda r: scores[r])
    if scores[best] > 0:
        logger.info("Routed step '%s' to %s (score=%d)", step.description[:60], best, scores[best])
        return best

    # Default to coder
    return AgentRole.CODER