package loop

import (
	"context"
	"log/slog"

	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/agent"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/guardrail"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/memory"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/model"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/persist"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/tool"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/trace"
)

// Options configures a Loop. All fields are optional and nil is tolerated until
// the step that actually needs the field: the agent is required for Run (Run
// returns ErrNilAgent otherwise); a missing tool dispatcher causes a requested
// call to be fed back as an error; a missing retriever/persona skips memory
// injection; a missing extractor/store skips the memory hook; a missing
// checkpoint skips persistence; a missing tracer skips tracing.
type Options struct {
	// Agent is the loop's execution unit: an instruction string plus a backend
	// adapter, an optional tool dispatcher and optional guardrails.
	Agent *agent.Agent
	// Tools is the tool dispatcher used to execute model-requested calls. When
	// nil the loop falls back to the agent's own dispatcher (if any).
	Tools *tool.Dispatcher
	// Memory is the long-term memory store used to persist extracted items.
	Memory *memory.Store
	// Retriever injects relevant memories into the context, re-evaluated every
	// round (see assembleContext) so retrieval tracks the latest conversation.
	Retriever *memory.Retriever
	// WorkingMemory is the per-session sliding window, provided for the
	// orchestrator to inspect; the loop does not mutate it.
	WorkingMemory *memory.WorkingMemory
	// Extractor derives memory items to persist after every step.
	Extractor memory.Extractor
	// Checkpoint persists a durable snapshot of the loop state at every step.
	Checkpoint *persist.Store
	// Tracer emits a structured span for every step, LLM call and tool call.
	Tracer *trace.Tracer
	// Guards validates request/response payloads on the streaming path, where
	// RunStep is bypassed. On the non-streaming path the agent runs its own
	// guardrails inside RunStep.
	Guards *guardrail.Pipeline
	// PersonaID scopes memory retrieval and extraction. Blank skips both.
	PersonaID string
	// MaxRounds is the tool-loop upper bound. Non-positive selects
	// DefaultMaxRounds (8).
	MaxRounds int
	// OnStream, when non-nil, switches the loop to the streaming path: the model
	// adapter's ChatStream is driven directly and each structured stream event is
	// forwarded to this callback (model.StreamEvent), so the frontend can render
	// body text, tool calls and (eventually) reasoning segments independently.
	OnStream func(model.StreamEvent)
	// ToolExecution selects how a batch of tool calls is run: "parallel" (the
	// default) or "sequential". Empty means parallel.
	ToolExecution string
	// ToolParallelism caps how many tool calls run concurrently when ToolExecution
	// is "parallel". Non-positive selects DefaultToolParallelism (4).
	ToolParallelism int
	// Hooks installs optional per-batch/per-call tool-loop hooks. Every field is
	// nil-tolerant; these are reserved for "敏感操作代审" (design/11) and the
	// future asynchronous-tool path. A zero Hooks value is a no-op.
	Hooks ToolLoopHooks
	// MaxContextTokens is the context budget that triggers overflow compaction.
	// Non-positive (the zero value) disables compaction, preserving the loop's
	// previous behavior. Setting it to a positive value (e.g.
	// DefaultMaxContextTokens) enables compaction: when the loop's estimated
	// context exceeds the budget it summarizes older turns into a leading summary
	// message while keeping the recent tail (including trailing tool results)
	// intact (design §1.3). Nil-tolerant: leaving it unset changes nothing.
	MaxContextTokens int
	// Compactor compacts an over-budget conversation. Nil selects the built-in
	// structural compactor (no model call); a non-nil value lets a caller inject
	// an LLM-backed or custom summarizer. It is only invoked when
	// MaxContextTokens is positive.
	Compactor Compactor
	// Vision, when non-nil, rewrites an image-bearing user message at the start
	// of Run so the main model can reason over the image (design/06 §0). The
	// concrete resolver (vision.MessageResolver) decides via the vision Router
	// whether to keep the image for a vision-capable main model or fold it into a
	// text description from the vision/OCR tool ("先看图再对话"). Nil keeps the
	// image content as-is, passing it through to a vision-capable main model.
	Vision ImageResolver
	// TransformContext, when non-nil, is called immediately before every model
	// step with the assembled message list (after memory injection and any
	// compaction) and the current round number (1-based). It may project, filter
	// or re-order the messages the model sees. It is the loop's equivalent of
	// OpenClaw's transformContext (design §1.3). Nil = no projection.
	TransformContext func(ctx context.Context, messages []model.Message, round int) []model.Message
	// Log is the base logger. Nil is replaced with a discard logger tagged with
	// source "runtime/loop".
	Log *slog.Logger
}