package tool

import "fmt"

// CheckGate returns an error if the invocation context's SkillName does
// not match the tool's gate. Tools should call this at the top of their
// handler when their Permission has a non-empty SkillNameGate.
//
// Why: the gate is enforced per-call (not per-build) because the same
// Tool may be referenced by multiple skills, only one of which is
// gate-eligible. Build cannot know in advance which skill will call it
// — that's per-Invocation.
//
// What: returns nil if no gate, or the names match. Returns an error
// suitable for surfacing to the LLM as the tool's failure result.
func CheckGate(inv Invocation) error {
	if inv.gate == "" {
		return nil
	}
	if inv.currentSkill == inv.gate {
		return nil
	}
	return fmt.Errorf("tool %q is restricted to the %q skill", inv.toolName, inv.gate)
}

// EmitAudit forwards a tool's call+result to the audit hook, if one is
// wired. Tools should call this once per Execute, after the underlying
// work has completed (regardless of error). Pass the original args
// JSON, the result string, and any error.
//
// Why: keeping the audit emission inside the tool ensures the captured
// args are exactly what the tool ran with (after coercion / defaults),
// not the raw LLM JSON which can drift.
func EmitAudit(inv Invocation, args, result string, err error) {
	if inv.audit == nil {
		return
	}
	inv.audit(AuditCall{
		Tool:   inv.toolName,
		Args:   args,
		Result: result,
		Err:    err,
	})
}