package run

import (
	"context"
	"time"

	"gitea.stevedudenhoeffer.com/steve/majordomo/agent"
)

// criticDeadlineCheck is how often the deadline-watch goroutine polls the
// critic's hard deadline. Small relative to any realistic soft timeout.
const criticDeadlineCheck = time.Second

// criticBinding wires a CriticHandle into a run: the executor forwards activity
// (steps + tool starts) to it, binds the run's hard cancellation to the critic's
// extendable deadline, and exposes the critic's Steer messages as an agent
// RunOption. All methods are nil-safe so the executor can call them
// unconditionally when no critic is configured.
type criticBinding struct {
	h CriticHandle
}

// startCritic begins critic monitoring for this run when one is configured and
// the agent enables it. It launches a goroutine that cancels runCtx (via cancel)
// the moment the critic's hard deadline passes — the critic may extend that
// deadline, so a healthy-but-slow run is given room while a hung one is killed.
// Returns (nil, no-op stop) when there is no critic. The caller MUST defer the
// returned stop.
func (e *Executor) startCritic(runCtx context.Context, cancel context.CancelFunc, ra RunnableAgent, info RunInfo) (*criticBinding, func()) {
	noop := func() {}
	if e.cfg.Ports.Critic == nil || !ra.Critic.Enabled {
		return nil, noop
	}
	soft := e.cfg.Defaults.CriticSoftTimeout
	if soft <= 0 {
		soft = 90 * time.Second // defensive: withFallbacks normally guarantees >0
	}
	h := e.cfg.Ports.Critic.Monitor(runCtx, info, soft)
	if h == nil {
		return nil, noop
	}
	done := make(chan struct{})
	go func() {
		// A host CriticHandle.Deadline() that panics must not crash the process
		// (this runs on its own goroutine, so the executor's top-level recover
		// can't catch it). Log-free best-effort: just stop watching.
		defer func() { _ = recover() }()
		t := time.NewTicker(criticDeadlineCheck)
		defer t.Stop()
		for {
			select {
			case <-done:
				return
			case <-runCtx.Done():
				return
			case <-t.C:
				// A zero deadline = no hard cap (not yet set); otherwise cancel
				// once we're at or past it.
				if d := h.Deadline(); !d.IsZero() && !time.Now().Before(d) {
					cancel()
					return
				}
			}
		}
	}()
	return &criticBinding{h: h}, func() {
		close(done)
		h.Stop()
	}
}

func (b *criticBinding) recordStep(iter int) {
	if b != nil {
		b.h.RecordStep(iter)
	}
}

// recordToolStart forwards a tool call to the critic. NOTE: majordomo's step
// observer only fires AFTER an iteration completes, so this currently lands
// post-tool, not at dispatch — the activity clock is refreshed once per
// iteration, not mid-tool. A single very long tool call (e.g. a 30-min render)
// therefore won't refresh the clock until it returns; a host that runs such
// tools should feed interim progress to its Critic (mort's InstallProgressBridge
// pattern). A true pre-dispatch refresh needs a majordomo hook (follow-up).
func (b *criticBinding) recordToolStart(name, args string) {
	if b != nil {
		b.h.RecordToolStart(name, args)
	}
}

// maxStepsOption returns the agent step-ceiling Option. With no critic it's a
// fixed WithMaxSteps(base); with a critic it's a DYNAMIC WithMaxStepsFunc that
// polls the handle each step (so the critic can raise a long run's budget),
// falling back to base when the handle defers (MaxSteps() <= 0).
func (b *criticBinding) maxStepsOption(base int) agent.Option {
	if b == nil {
		return agent.WithMaxSteps(base)
	}
	return agent.WithMaxStepsFunc(func() int {
		if n := b.h.MaxSteps(); n > 0 {
			return n
		}
		return base
	})
}

// steerOptions returns the agent RunOptions that drain the critic's steer
// messages into the loop. Empty when there is no critic.
func (b *criticBinding) steerOptions() []agent.RunOption {
	if b == nil {
		return nil
	}
	return []agent.RunOption{agent.WithSteer(b.h.Steer)}
}