package eino

import (
	"context"
	"fmt"
	"strconv"
	"strings"
	"time"

	"github.com/cloudwego/eino/schema"

	"github.com/sundynix/sundynix-dispatcher/internal/dsl"
	"github.com/sundynix/sundynix-shared/contract"
)

// defaultAgentSystem 是 agent 节点未填系统提示词时的兜底。
const defaultAgentSystem = "你是 sundynix-agentix 平台的 AI 助手。"

// board 是图执行的"黑板"：节点按拓扑序流转时读写它。
type board struct {
	uid, sid string
	query    string
	profile  string
	history  []*schema.Message
	kb       string          // 最近一个检索节点的 owner 作用域库名（供 map 并行各项检索）
	refs     []string        // 检索 / 聚合得到的参考资料
	toolOut  []string        // 工具节点产出
	sections []reportSection // map 并行 fan-out 产出的分项成稿（供 render 多章渲染）
	answer   string          // 终端 agent / map 的成稿（流式累计）
}

// runGraph 按 DSL 图的真实拓扑与连线执行（替代旧的线性拍平 compileFlow）。
//
//	入度0 入口 → 沿连线传播 active → 每个节点按 kind 执行真实行为 →
//	branch 按条件只激活选中的下游（剪枝）→ agent 节点流式回流 token。
//
// 逐节点点亮"运行·观测"。返回终端 agent 的完整产出（供写回历史）。
func (o *Orchestrator) runGraph(ctx context.Context, t *contract.Task, tr *execTracer) (string, error) {
	flow, ferr := dsl.Parse(t.Graph)
	plan := dsl.Compile(t.Graph)
	b := &board{
		uid:   meta(t, contract.MetaUserID),
		sid:   meta(t, contract.MetaSessionID),
		query: plan.Query,
	}

	// 无法解析或空图：退化为"无图单轮对话"（注入默认记忆 + 直接出模型）。
	if ferr != nil || flow == nil || len(flow.Nodes) == 0 {
		tr.info("task", "system", "无结构化图", "按单轮对话执行")
		b.profile = o.fetchMemory(ctx, b.uid, b.query)
		b.history = o.fetchHistory(ctx, b.sid)
		o.runAgent(ctx, t.ID, b, plan.System, tr, "agent")
		return b.answer, nil
	}

	// 建邻接与入度（只认两端都存在的边）。保留整条边以便 branch 按 true/false 标签选路。
	nodeByID := make(map[string]dsl.Node, len(flow.Nodes))
	outE := make(map[string][]dsl.Edge)
	indeg := make(map[string]int, len(flow.Nodes))
	for _, n := range flow.Nodes {
		nodeByID[n.ID] = n
		indeg[n.ID] = 0
	}
	for _, e := range flow.Edges {
		if _, ok := nodeByID[e.Source]; !ok {
			continue
		}
		if _, ok := nodeByID[e.Target]; !ok {
			continue
		}
		outE[e.Source] = append(outE[e.Source], e)
		indeg[e.Target]++
	}

	// 入口节点（入度 0）置 active；执行时沿连线把下游激活，branch 只激活选中分支。
	active := make(map[string]bool)
	for _, n := range flow.Nodes {
		if indeg[n.ID] == 0 {
			active[n.ID] = true
		}
	}

	// 图里没有 memory 节点 → 沿用旧默认：注入画像+历史（避免回归）。
	hasMemory := false
	for _, n := range flow.Nodes {
		if n.Kind == "memory" {
			hasMemory = true
			break
		}
	}
	if !hasMemory {
		b.profile = o.fetchMemory(ctx, b.uid, b.query)
		b.history = o.fetchHistory(ctx, b.sid)
	}

	for _, n := range flow.Topo() {
		if !active[n.ID] {
			continue // 被 branch 剪掉的下游，不执行
		}
		propagate := targetsOf(outE[n.ID]) // 默认激活全部出边；branch 会改写
		switch n.Kind {
		case "input":
			if txt := cstr(n.Config, "text"); txt != "" {
				b.query = txt
			}
			tr.info("input:"+n.ID, "system", labelOf(n, "输入"), truncate(b.query, 80))
		case "memory":
			if cbool(n.Config, "profile") {
				b.profile = o.fetchMemory(ctx, b.uid, b.query)
			}
			if cbool(n.Config, "history") {
				b.history = o.fetchHistory(ctx, b.sid)
			}
			tr.info("memory:"+n.ID, "memory", labelOf(n, "记忆"),
				fmt.Sprintf("画像 %d 字 · 历史 %d 条", len([]rune(b.profile)), len(b.history)))
		case "retriever":
			o.retrieverNode(ctx, n, b, tr)
		case "tool":
			o.execToolNode(ctx, t.ID, n, b, tr)
		case "agent":
			o.runAgent(ctx, t.ID, b, firstNonEmpty(cstr(n.Config, "system"), plan.System), tr, "agent:"+n.ID)
		case "aggregate":
			merged := aggregate(cstr(n.Config, "strategy"), append(append([]string{}, b.refs...), b.toolOut...))
			b.refs, b.toolOut = merged, nil
			tr.info("aggregate:"+n.ID, "system", labelOf(n, "汇聚"), "策略："+firstNonEmpty(cstr(n.Config, "strategy"), "拼接"))
		case "render":
			o.renderNode(ctx, t.ID, n, b, tr)
		case "branch":
			propagate = o.branchNode(n, b, outE[n.ID], nodeByID, tr)
		case "map":
			o.mapNode(ctx, t.ID, n, b, tr)
		case "output":
			tr.info("output:"+n.ID, "system", labelOf(n, "输出"), "目标："+firstNonEmpty(cstr(n.Config, "target"), "屏幕"))
		default:
			tr.info(n.Kind+":"+n.ID, "system", labelOf(n, n.Kind), "未识别节点，跳过")
		}
		for _, tgt := range propagate {
			active[tgt] = true
		}
	}

	// 图里无 agent 节点（纯工具/检索图）也要出一段模型答复，否则没有输出。
	if b.answer == "" {
		o.runAgent(ctx, t.ID, b, plan.System, tr, "agent")
	}
	return b.answer, nil
}

// retrieverNode 执行检索节点：kb 按 owner 作用域 → kb_search → 累计参考资料。
func (o *Orchestrator) retrieverNode(ctx context.Context, n dsl.Node, b *board, tr *execTracer) {
	kb := cstr(n.Config, "kb")
	scoped := kb
	if b.uid != "" && kb != "" && !strings.Contains(kb, "/") {
		scoped = b.uid + "/" + kb
	}
	if scoped != "" {
		b.kb = scoped // 记下作用域库名，供后续 map 并行各项检索复用
	}
	end := tr.span("retriever:"+n.ID, "tool", labelOf(n, "检索"))
	refs := o.retrieve(ctx, scoped, b.query)
	if refs != "" {
		b.refs = append(b.refs, refs)
	}
	end(fmt.Sprintf("kb=%s · 命中 %d 段", firstNonEmpty(kb, "（未指定）"), countLines(refs)), nil)
}

// mapNode 执行并行 fan-out：把主题拆成若干项，各项有界并发撰写（复用 report 的 writeSections），
// 成稿存入黑板（结构化 sections + 拼进 answer），并流式呈现进度。
func (o *Orchestrator) mapNode(ctx context.Context, taskID string, n dsl.Node, b *board, tr *execTracer) {
	end := tr.span("map:"+n.ID, "plan", labelOf(n, "并行 fan-out"))
	items := o.planItems(ctx, b.query, cstr(n.Config, "splitBy"))
	end(fmt.Sprintf("拆出 %d 项：%s", len(items), strings.Join(items, " / ")), nil)

	o.emit(taskID, fmt.Sprintf("\n> 并行处理 %d 项…\n\n", len(items)))
	secs := o.writeSections(ctx, b.query, b.kb, items, tr) // 有界并发，trace 出 section:i 各项
	b.sections = secs
	for _, s := range secs {
		chunk := "## " + s.Heading + "\n\n" + s.Body + "\n\n"
		o.emit(taskID, chunk)
		b.answer += chunk
		b.refs = append(b.refs, s.Heading+"："+s.Body)
	}
}

// execToolNode 执行工具节点：调 MCP 工具，产出累计进黑板；失败降级不阻断。
func (o *Orchestrator) execToolNode(ctx context.Context, taskID string, n dsl.Node, b *board, tr *execTracer) {
	tool, args := dsl.ToolBinding(n)
	if tool == "" {
		return
	}
	node := "tool:" + tool
	if o.tools == nil {
		tr.info(node, "tool", "工具 "+tool, "工具总线未接入，跳过")
		return
	}
	call := map[string]any{}
	for k, v := range args {
		call[k] = v
	}
	if call["q"] == nil && call["query"] == nil {
		call["q"] = b.query
	}
	if b.uid != "" {
		if kbv, ok := call["kb"].(string); ok && kbv != "" && !strings.Contains(kbv, "/") {
			call["kb"] = b.uid + "/" + kbv
		}
	}
	end := tr.span(node, "tool", "调用工具 "+tool)
	cctx, cancel := context.WithTimeout(ctx, toolCallTimeout)
	defer cancel()
	res, err := o.tools.CallTool(cctx, contract.ToolSubjectGo(tool), &contract.ToolCall{Tool: tool, TaskID: taskID, Args: call})
	if err != nil {
		end("调用失败，降级跳过", err)
		return
	}
	if res == nil || !res.OK || res.Content == "" {
		end("无结果，降级跳过", nil)
		return
	}
	end("入参 "+previewArgs(call)+" → 产出 "+truncate(res.Content, 160), nil)
	b.toolOut = append(b.toolOut, "["+tool+"] "+res.Content)
}

// runAgent 执行 agent/模型节点：据黑板拼消息 → 流式回流 token → 累计成稿。
func (o *Orchestrator) runAgent(ctx context.Context, taskID string, b *board, system string, tr *execTracer, node string) {
	rc := &RunCtx{
		System:  firstNonEmpty(system, defaultAgentSystem),
		Query:   b.query,
		Profile: b.profile,
		History: b.history,
		ToolOut: append(append([]string{}, b.toolOut...), b.refs...),
	}
	msgs, _ := buildMessages(ctx, rc)
	tr.emit(node, "model", "start", "模型流式推理", "", 0)
	t0 := time.Now()
	n := 0
	send := func(s string) {
		if s == "" {
			return
		}
		_ = o.sink.PublishToken(taskID, []byte(s))
		b.answer += s
		n++
	}
	var err error
	if o.pool.Ready() {
		err = o.pool.ChatStream(ctx, toChatMessages(msgs), send)
	} else {
		err = o.pool.StreamText(ctx, replyFor(msgs), func(tok []byte) { send(string(tok)) })
	}
	if err != nil {
		tr.emit(node, "model", "error", "模型流式推理", err.Error(), time.Since(t0).Milliseconds())
		return
	}
	tr.emit(node, "model", "end", "模型流式推理",
		fmt.Sprintf("%d tokens / %d 字", n, len([]rune(b.answer))), time.Since(t0).Milliseconds())
}

// renderNode 执行渲染节点：把当前成稿渲染成 Word（经 mcp-go report_render）。
func (o *Orchestrator) renderNode(ctx context.Context, taskID string, n dsl.Node, b *board, tr *execTracer) {
	if strings.TrimSpace(b.answer) == "" {
		tr.info("render:"+n.ID, "render", labelOf(n, "渲染"), "暂无正文可渲染（render 前需有 agent 产出）")
		return
	}
	format := firstNonEmpty(cstr(n.Config, "format"), "docx")
	end := tr.span("render:"+n.ID, "render", labelOf(n, "渲染 "+format))
	title := truncate(b.query, 40)
	secs := b.sections // map 产出的多章优先；否则把整段成稿当单章
	if len(secs) == 0 {
		secs = []reportSection{{Heading: title, Body: b.answer}}
	}
	if path := o.renderReport(ctx, taskID, title, secs); path != "" {
		end("已落盘："+path, nil)
		o.emit(taskID, "\n\n---\n✅ 已渲染 "+format+" 文档，可在「下载」获取。\n")
	} else {
		end("渲染服务不可用", fmt.Errorf("render unavailable"))
	}
}

// branchNode 执行分支节点：求值条件，按出边的 true/false 标签选出要激活的下游。
// 边带 sourceHandle("true"/"false") 时按标签精确选路（前端 Phase 2 给 branch 的边打标）；
// 无标签的旧图退回"出边顺序 [true,false]"约定，保持向后兼容。
func (o *Orchestrator) branchNode(n dsl.Node, b *board, outs []dsl.Edge, byID map[string]dsl.Node, tr *execTracer) []string {
	cond := cstr(n.Config, "condition")
	res := evalCondition(cond, b)

	var truthy, falsy []string
	labeled := false
	for _, e := range outs {
		switch e.SourceHandle {
		case "true":
			truthy = append(truthy, e.Target)
			labeled = true
		case "false":
			falsy = append(falsy, e.Target)
			labeled = true
		}
	}

	var chosen []string
	mode := "边标签"
	if labeled {
		if res {
			chosen = truthy
		} else {
			chosen = falsy
		}
	} else {
		mode = "边序约定[true,false]"
		targets := targetsOf(outs)
		switch {
		case len(targets) >= 2:
			if res {
				chosen = targets[:1]
			} else {
				chosen = targets[1:2]
			}
		case len(targets) == 1 && !res:
			chosen = nil
		default:
			chosen = targets
		}
	}

	names := make([]string, 0, len(chosen))
	for _, id := range chosen {
		names = append(names, labelOf(byID[id], id))
	}
	tr.info("branch:"+n.ID, "system", labelOf(n, "分支"),
		fmt.Sprintf("条件「%s」→ %v ⇒ 走 [%s]（%s）",
			firstNonEmpty(cond, "(空=真)"), res, strings.Join(names, ", "), mode))
	return chosen
}

// targetsOf 取一组边的目标节点 ID（保持顺序）。
func targetsOf(edges []dsl.Edge) []string {
	out := make([]string, 0, len(edges))
	for _, e := range edges {
		out = append(out, e.Target)
	}
	return out
}

// evalCondition 求值 branch 条件。支持：
//
//	空 → true；关键字 refs/tools/answer/profile 作左值（取数量/字数）；
//	形如 "a op b"（op: >= <= == != > <）数值比较；其余非空 → 默认真。
func evalCondition(cond string, b *board) bool {
	cond = strings.TrimSpace(cond)
	if cond == "" {
		return true
	}
	for _, op := range []string{">=", "<=", "==", "!=", ">", "<"} {
		if i := strings.Index(cond, op); i >= 0 {
			l := resolveOperand(strings.TrimSpace(cond[:i]), b)
			r := resolveOperand(strings.TrimSpace(cond[i+len(op):]), b)
			switch op {
			case ">":
				return l > r
			case "<":
				return l < r
			case ">=":
				return l >= r
			case "<=":
				return l <= r
			case "==":
				return l == r
			case "!=":
				return l != r
			}
		}
	}
	return true
}

// resolveOperand 把条件里的左/右值解析为数值（关键字取运行时数量，否则按字面量）。
func resolveOperand(s string, b *board) float64 {
	switch strings.ToLower(s) {
	case "refs":
		return float64(len(b.refs))
	case "tools":
		return float64(len(b.toolOut))
	case "answer":
		return float64(len([]rune(b.answer)))
	case "profile":
		return float64(len([]rune(b.profile)))
	}
	f, _ := strconv.ParseFloat(s, 64)
	return f
}

// aggregate 按策略合并多段参考资料为一段。
func aggregate(strategy string, parts []string) []string {
	var nonEmpty []string
	for _, p := range parts {
		if strings.TrimSpace(p) != "" {
			nonEmpty = append(nonEmpty, p)
		}
	}
	if len(nonEmpty) == 0 {
		return nil
	}
	switch strategy {
	case "去重合并":
		seen := map[string]bool{}
		var uniq []string
		for _, p := range nonEmpty {
			if !seen[p] {
				seen[p] = true
				uniq = append(uniq, p)
			}
		}
		return []string{strings.Join(uniq, "\n---\n")}
	case "摘要":
		return []string{truncate(strings.Join(nonEmpty, "\n"), 800)}
	default: // 拼接
		return []string{strings.Join(nonEmpty, "\n---\n")}
	}
}

// ---- 小工具 ----

func meta(t *contract.Task, key string) string {
	v, _ := t.Meta[key].(string)
	return v
}

func cstr(cfg map[string]any, key string) string {
	if cfg == nil {
		return ""
	}
	v, ok := cfg[key]
	if !ok || v == nil {
		return ""
	}
	if s, ok := v.(string); ok {
		return strings.TrimSpace(s)
	}
	return strings.TrimSpace(fmt.Sprint(v))
}

func cbool(cfg map[string]any, key string) bool {
	if cfg == nil {
		return false
	}
	if v, ok := cfg[key].(bool); ok {
		return v
	}
	return false
}

func labelOf(n dsl.Node, def string) string {
	if strings.TrimSpace(n.Label) != "" {
		return n.Label
	}
	return def
}

func countLines(s string) int {
	s = strings.TrimSpace(s)
	if s == "" {
		return 0
	}
	return strings.Count(s, "\n") + 1
}