package orchestration

import (
	"log/slog"
	"time"

	"git.yeij.top/AskaEth/Cyrene_v2/internal/bus"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/loop"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/memory"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/orchestration/audit"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/orchestration/comm"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/trace"
)

// Defaults for the orchestration layer.
const (
	// DefaultMaxParallel is the maximum number of sub-agents that run at once
	// when Options.MaxParallel is non-positive.
	DefaultMaxParallel = 4

	// defaultAgentID is the comm probe identity used when Options.AgentID is
	// blank and a probe must be built from Bus.
	defaultAgentID = "orchestrator"
)

// Options configures a Scheduler built by New. All fields are optional; each nil
// dependency degrades gracefully (a missing Loop makes sub-agents fail fast, a
// missing Comm skips progress events, a missing Approver makes Approve error,
// and so on).
type Options struct {
	// MaxParallel caps how many sub-agents execute concurrently. Excess sub-agents
	// queue until a slot frees. Non-positive selects DefaultMaxParallel (4).
	MaxParallel int

	// PerAgentTimeout bounds every sub-agent's run. When it elapses the sub-agent
	// is aborted (status aborted). Non-positive means no timeout.
	PerAgentTimeout time.Duration

	// Loop is the execution template: a *loop.Loop used to run every sub-agent.
	// It must be safe for concurrent Run calls (as loop.Loop documents); the
	// template's agent/tools/guardrails/persona apply to every sub-agent. When
	// nil, sub-agents fail fast with ErrNoRunner.
	Loop *loop.Loop

	// Bus is the in-process event bus used for progress events and, when Comm is
	// nil, to build a default comm probe. When nil no events are published.
	Bus bus.Bus

	// Comm is the comm probe used to publish progress events. When nil, a probe
	// bound to AgentID is built from Bus (when Bus is non-nil).
	Comm *comm.Probe

	// Memory is the long-term memory store used by SinkMemory. Optional.
	Memory *memory.Store

	// Tracer emits a per-sub-agent span (kind subagent) around each run. Optional.
	Tracer *trace.Tracer

	// Flow, when non-nil, receives the sub-agent span transitions so a spawned
	// branch appears in the flow graph of the session named by
	// AgentSpec.ParentSession (design/19 §2). *loop.FlowPublisher is the
	// production implementation. Optional: a nil sink leaves sub-agent branches
	// unvisualized (the sub-agent's own inner spans still fold into the parent
	// graph through the loop's flow branch).
	Flow FlowSpanSink

	// Approver records sensitive-operation review-and-approve (代审) triggered by
	// Approve. Policy judgement belongs to the upper layer. Optional.
	Approver *audit.Approver

	// PersonaExists reports whether a role id can run with its own instructions,
	// i.e. whether the per-role agent pool behind Loop (loop.Options.Agents) has an
	// entry for it (design/22 §8-2). It gates AgentSpec.PersonaID: a dispatch naming
	// an id this returns false for is rejected with ErrUnknownPersona rather than
	// running as the default role's prompt. Nil means "this deployment knows no
	// role", so a dispatch that names a role is rejected too — deciding nothing
	// silently is the point. Omitting the persona is unaffected by this.
	PersonaExists func(personaID string) bool

	// Logger is the base logger. Nil is replaced with a discard logger tagged with
	// source "orchestration".
	Logger *slog.Logger

	// AgentID is the comm probe identity. When blank and a probe must be built
	// from Bus, "orchestrator" is used.
	AgentID string
}

// FlowSpanSink folds a span transition into a session's live flow graph so the
// realtime visualization shows the work in flight (design/19 §1). *loop.FlowPublisher
// is the production implementation; tests substitute a capturing fake. The
// interface keeps orchestration from depending on the concrete publisher beyond
// the loop template it already takes.
type FlowSpanSink interface {
	// SpanStarted registers a running placeholder node for a span that just began.
	SpanStarted(sessionID string, sp *trace.Span)
	// SpanFinished folds a just-finished span into the session graph.
	SpanFinished(sessionID string, sp *trace.Span)
}

// wrapLoop adapts a *loop.Loop into the runner interface, substituting a no-op
// runner (fail-fast) when the template is nil.
func wrapLoop(l *loop.Loop) runner {
	if l == nil {
		return noopRunner{}
	}
	return l
}

// scopedRunner picks the runner that executes sub: without a tool whitelist the
// configured template runs as-is（缺省全开，继承主 agent 全量工具集）；with one,
// a *loop.Loop template is derived through WithToolWhitelist so only the listed
// tools pass（design/05 §7 裁决 02.4.1）. A non-loop runner (tests inject mocks)
// is returned unchanged — the whitelist still rides the run context for it to
// observe via loop.ToolWhitelistFrom.
func (s *Scheduler) scopedRunner(sub *SubAgent) runner {
	if len(sub.ToolWhitelist) == 0 {
		return s.runner
	}
	if lp, ok := s.runner.(*loop.Loop); ok {
		return lp.WithToolWhitelist(sub.ToolWhitelist)
	}
	return s.runner
}

// effectiveTimeout resolves the deadline one sub-agent runs under: a positive
// per-call override wins; otherwise the scheduler's PerAgentTimeout applies
// (non-positive = no deadline).
func effectiveTimeout(override, schedulerDefault time.Duration) time.Duration {
	if override > 0 {
		return override
	}
	return schedulerDefault
}