package multiagent

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"path/filepath"
	"strings"
	"sync"
	"sync/atomic"

	"cyberstrike-ai/internal/einomcp"

	"github.com/cloudwego/eino/adk"
	"github.com/cloudwego/eino/schema"
	"go.uber.org/zap"
)

func isEinoIterationLimitError(err error) bool {
	if err == nil {
		return false
	}
	msg := strings.ToLower(strings.TrimSpace(err.Error()))
	if msg == "" {
		return false
	}
	return strings.Contains(msg, "max iteration") ||
		strings.Contains(msg, "maximum iteration") ||
		strings.Contains(msg, "maximum iterations") ||
		strings.Contains(msg, "iteration limit") ||
		strings.Contains(msg, "达到最大迭代")
}

// einoADKRunLoopArgs 将 Eino adk.Runner 事件循环从 RunDeepAgent / RunEinoSingleChatModelAgent 中抽出复用。
type einoADKRunLoopArgs struct {
	OrchMode             string
	OrchestratorName     string
	ConversationID       string
	Progress             func(eventType, message string, data interface{})
	Logger               *zap.Logger
	SnapshotMCPIDs       func() []string
	StreamsMainAssistant func(agent string) bool
	EinoRoleTag          func(agent string) string
	CheckpointDir        string

	McpIDsMu *sync.Mutex
	McpIDs   *[]string

	DA adk.Agent

	// EmptyResponseMessage 当未捕获到助手正文时的占位（多代理与单代理文案不同）。
	EmptyResponseMessage string
}

func runEinoADKAgentLoop(ctx context.Context, args *einoADKRunLoopArgs, baseMsgs []adk.Message) (*RunResult, error) {
	if args == nil || args.DA == nil {
		return nil, fmt.Errorf("eino run loop: args 或 Agent 为空")
	}
	if args.McpIDs == nil {
		s := []string{}
		args.McpIDs = &s
	}
	if args.McpIDsMu == nil {
		args.McpIDsMu = &sync.Mutex{}
	}

	orchMode := args.OrchMode
	orchestratorName := args.OrchestratorName
	conversationID := args.ConversationID
	progress := args.Progress
	logger := args.Logger
	snapshotMCPIDs := args.SnapshotMCPIDs
	if snapshotMCPIDs == nil {
		snapshotMCPIDs = func() []string { return nil }
	}
	streamsMainAssistant := args.StreamsMainAssistant
	if streamsMainAssistant == nil {
		streamsMainAssistant = func(agent string) bool {
			return agent == "" || agent == orchestratorName
		}
	}
	einoRoleTag := args.EinoRoleTag
	if einoRoleTag == nil {
		einoRoleTag = func(agent string) string {
			if streamsMainAssistant(agent) {
				return "orchestrator"
			}
			return "sub"
		}
	}
	da := args.DA
	mcpIDsMu := args.McpIDsMu
	mcpIDs := args.McpIDs

	// panic recovery：防止 Eino 框架内部 panic 导致整个 goroutine 崩溃、连接无法正常关闭。
	defer func() {
		if r := recover(); r != nil {
			if logger != nil {
				logger.Error("eino runner panic recovered", zap.Any("recover", r), zap.Stack("stack"))
			}
			if progress != nil {
				progress("error", fmt.Sprintf("Internal error: %v / 内部错误: %v", r, r), map[string]interface{}{
					"conversationId": conversationID,
					"source":         "eino",
				})
			}
		}
	}()

	var lastRunMsgs []adk.Message
	var lastAssistant string
	var lastPlanExecuteExecutor string
	msgs := append([]adk.Message(nil), baseMsgs...)
	runAccumulatedMsgs := append([]adk.Message(nil), msgs...)

	emptyHint := strings.TrimSpace(args.EmptyResponseMessage)
	if emptyHint == "" {
		emptyHint = "(Eino session completed but no assistant text was captured. Check process details or logs.) " +
			"（Eino 会话已完成，但未捕获到助手文本输出。请查看过程详情或日志。）"
	}

	lastAssistant = ""
	lastPlanExecuteExecutor = ""
	var reasoningStreamSeq int64
	var einoSubReplyStreamSeq int64
	toolEmitSeen := make(map[string]struct{})
	var einoMainRound int
	var einoLastAgent string
	subAgentToolStep := make(map[string]int)
	pendingByID := make(map[string]toolCallPendingInfo)
	pendingQueueByAgent := make(map[string][]string)
	markPending := func(tc toolCallPendingInfo) {
			if tc.ToolCallID == "" {
				return
			}
			pendingByID[tc.ToolCallID] = tc
			pendingQueueByAgent[tc.EinoAgent] = append(pendingQueueByAgent[tc.EinoAgent], tc.ToolCallID)
		}
		popNextPendingForAgent := func(agentName string) (toolCallPendingInfo, bool) {
			q := pendingQueueByAgent[agentName]
			for len(q) > 0 {
				id := q[0]
				q = q[1:]
				pendingQueueByAgent[agentName] = q
				if tc, ok := pendingByID[id]; ok {
					delete(pendingByID, id)
					return tc, true
				}
			}
			return toolCallPendingInfo{}, false
		}
		removePendingByID := func(toolCallID string) {
			if toolCallID == "" {
				return
			}
			delete(pendingByID, toolCallID)
		}
		flushAllPendingAsFailed := func(err error) {
			if progress == nil {
				pendingByID = make(map[string]toolCallPendingInfo)
				pendingQueueByAgent = make(map[string][]string)
				return
			}
			msg := ""
			if err != nil {
				msg = err.Error()
			}
			for _, tc := range pendingByID {
				toolName := tc.ToolName
				if strings.TrimSpace(toolName) == "" {
					toolName = "unknown"
				}
				progress("tool_result", fmt.Sprintf("工具结果 (%s)", toolName), map[string]interface{}{
					"toolName":       toolName,
					"success":        false,
					"isError":        true,
					"result":         msg,
					"resultPreview":  msg,
					"toolCallId":     tc.ToolCallID,
					"conversationId": conversationID,
					"einoAgent":      tc.EinoAgent,
					"einoRole":       tc.EinoRole,
					"source":         "eino",
				})
			}
			pendingByID = make(map[string]toolCallPendingInfo)
			pendingQueueByAgent = make(map[string][]string)
		}

		runnerCfg := adk.RunnerConfig{
			Agent:           da,
			EnableStreaming: true,
		}
		if cp := strings.TrimSpace(args.CheckpointDir); cp != "" {
			cpDir := filepath.Join(cp, sanitizeEinoPathSegment(conversationID))
			st, stErr := newFileCheckPointStore(cpDir)
			if stErr != nil {
				if logger != nil {
					logger.Warn("eino checkpoint store disabled", zap.String("dir", cpDir), zap.Error(stErr))
				}
			} else {
				runnerCfg.CheckPointStore = st
				if logger != nil {
					logger.Info("eino runner: checkpoint store enabled", zap.String("dir", cpDir))
				}
			}
		}
	runner := adk.NewRunner(ctx, runnerCfg)
	iter := runner.Run(ctx, msgs)
	handleRunErr := func(runErr error) error {
			if runErr == nil {
				return nil
			}
			if errors.Is(runErr, context.DeadlineExceeded) {
				flushAllPendingAsFailed(runErr)
				if progress != nil {
					progress("error", runErr.Error(), map[string]interface{}{
						"conversationId": conversationID,
						"source":         "eino",
						"errorKind":      "timeout",
					})
				}
				return runErr
			}
			// context.Canceled 是唯一应当直接终止编排的错误（用户关闭页面、主动停止等）。
			if errors.Is(runErr, context.Canceled) {
				flushAllPendingAsFailed(runErr)
				if progress != nil {
					progress("error", runErr.Error(), map[string]interface{}{
						"conversationId": conversationID,
						"source":         "eino",
					})
				}
				return runErr
			}
			if isEinoIterationLimitError(runErr) {
				flushAllPendingAsFailed(runErr)
				if progress != nil {
					progress("iteration_limit_reached", runErr.Error(), map[string]interface{}{
						"conversationId": conversationID,
						"source":         "eino",
						"orchestration":  orchMode,
					})
					progress("error", runErr.Error(), map[string]interface{}{
						"conversationId": conversationID,
						"source":         "eino",
						"errorKind":      "iteration_limit",
					})
				}
				return runErr
			}
			flushAllPendingAsFailed(runErr)
			if progress != nil {
				progress("error", runErr.Error(), map[string]interface{}{
					"conversationId": conversationID,
					"source":         "eino",
				})
			}
			return runErr
		}

		for {
			// 检测 context 取消（用户关闭浏览器、请求超时等），flush pending 工具状态避免 UI 卡在 "执行中"。
			select {
			case <-ctx.Done():
				flushAllPendingAsFailed(ctx.Err())
				if progress != nil {
					progress("error", "Request cancelled / 请求已取消", map[string]interface{}{
						"conversationId": conversationID,
						"source":         "eino",
					})
				}
				return nil, ctx.Err()
			default:
			}

			ev, ok := iter.Next()
			if !ok {
				if len(pendingByID) > 0 {
					orphanCount := len(pendingByID)
					flushAllPendingAsFailed(errors.New("pending tool call missing result before run completion"))
					if progress != nil {
						progress("eino_pending_orphaned", "pending tool calls were force-closed at run end", map[string]interface{}{
							"conversationId": conversationID,
							"source":         "eino",
							"orchestration":  orchMode,
							"pendingCount":   orphanCount,
						})
					}
				}
				lastRunMsgs = runAccumulatedMsgs
				break
			}
			if ev == nil {
				continue
			}
			if ev.Err != nil {
				if retErr := handleRunErr(ev.Err); retErr != nil {
					return nil, retErr
				}
			}
			if ev.AgentName != "" && progress != nil {
				iterEinoAgent := orchestratorName
				if orchMode == "plan_execute" {
					if a := strings.TrimSpace(ev.AgentName); a != "" {
						iterEinoAgent = a
					}
				}
				if streamsMainAssistant(ev.AgentName) {
					if einoMainRound == 0 {
						einoMainRound = 1
						progress("iteration", "", map[string]interface{}{
							"iteration":        1,
							"einoScope":        "main",
							"einoRole":         "orchestrator",
							"einoAgent":        iterEinoAgent,
							"orchestration":    orchMode,
							"conversationId":   conversationID,
							"source":           "eino",
						})
					} else if einoLastAgent != "" && !streamsMainAssistant(einoLastAgent) {
						einoMainRound++
						progress("iteration", "", map[string]interface{}{
							"iteration":        einoMainRound,
							"einoScope":        "main",
							"einoRole":         "orchestrator",
							"einoAgent":        iterEinoAgent,
							"orchestration":    orchMode,
							"conversationId":   conversationID,
							"source":           "eino",
						})
					}
				}
				einoLastAgent = ev.AgentName
				progress("progress", fmt.Sprintf("[Eino] %s", ev.AgentName), map[string]interface{}{
					"conversationId": conversationID,
					"einoAgent":      ev.AgentName,
					"einoRole":       einoRoleTag(ev.AgentName),
					"orchestration":  orchMode,
				})
			}
			if ev.Output == nil || ev.Output.MessageOutput == nil {
				continue
			}
			mv := ev.Output.MessageOutput

			if mv.IsStreaming && mv.MessageStream != nil {
				streamHeaderSent := false
				var reasoningStreamID string
				var toolStreamFragments []schema.ToolCall
				var subAssistantBuf strings.Builder
				var subReplyStreamID string
				var mainAssistantBuf strings.Builder
				var streamRecvErr error
				for {
					chunk, rerr := mv.MessageStream.Recv()
					if rerr != nil {
						if errors.Is(rerr, io.EOF) {
							break
						}
						if logger != nil {
							logger.Warn("eino stream recv error, flushing incomplete stream",
								zap.Error(rerr),
								zap.String("agent", ev.AgentName),
								zap.Int("toolFragments", len(toolStreamFragments)))
						}
						streamRecvErr = rerr
						break
					}
					if chunk == nil {
						continue
					}
					if progress != nil && strings.TrimSpace(chunk.ReasoningContent) != "" {
						if reasoningStreamID == "" {
							reasoningStreamID = fmt.Sprintf("eino-reasoning-%s-%d", conversationID, atomic.AddInt64(&reasoningStreamSeq, 1))
							progress("thinking_stream_start", " ", map[string]interface{}{
								"streamId":      reasoningStreamID,
								"source":        "eino",
								"einoAgent":     ev.AgentName,
								"einoRole":      einoRoleTag(ev.AgentName),
								"orchestration": orchMode,
							})
						}
						progress("thinking_stream_delta", chunk.ReasoningContent, map[string]interface{}{
							"streamId": reasoningStreamID,
						})
					}
					if chunk.Content != "" {
						if progress != nil && streamsMainAssistant(ev.AgentName) {
							if !streamHeaderSent {
								progress("response_start", "", map[string]interface{}{
									"conversationId":     conversationID,
									"mcpExecutionIds":    snapshotMCPIDs(),
									"messageGeneratedBy": "eino:" + ev.AgentName,
									"einoRole":           "orchestrator",
									"einoAgent":          ev.AgentName,
									"orchestration":      orchMode,
								})
								streamHeaderSent = true
							}
							progress("response_delta", chunk.Content, map[string]interface{}{
								"conversationId":  conversationID,
								"mcpExecutionIds": snapshotMCPIDs(),
								"einoRole":        "orchestrator",
								"einoAgent":       ev.AgentName,
								"orchestration":   orchMode,
							})
							mainAssistantBuf.WriteString(chunk.Content)
						} else if !streamsMainAssistant(ev.AgentName) {
							if progress != nil {
								if subReplyStreamID == "" {
									subReplyStreamID = fmt.Sprintf("eino-sub-reply-%s-%d", conversationID, atomic.AddInt64(&einoSubReplyStreamSeq, 1))
									progress("eino_agent_reply_stream_start", "", map[string]interface{}{
										"streamId":       subReplyStreamID,
										"einoAgent":      ev.AgentName,
										"einoRole":       "sub",
										"conversationId": conversationID,
										"source":         "eino",
									})
								}
								progress("eino_agent_reply_stream_delta", chunk.Content, map[string]interface{}{
									"streamId":       subReplyStreamID,
									"conversationId": conversationID,
								})
							}
							subAssistantBuf.WriteString(chunk.Content)
						}
					}
					if len(chunk.ToolCalls) > 0 {
						toolStreamFragments = append(toolStreamFragments, chunk.ToolCalls...)
					}
				}
				if streamsMainAssistant(ev.AgentName) {
					if s := strings.TrimSpace(mainAssistantBuf.String()); s != "" {
						lastAssistant = s
						runAccumulatedMsgs = append(runAccumulatedMsgs, schema.AssistantMessage(s, nil))
						if orchMode == "plan_execute" && strings.EqualFold(strings.TrimSpace(ev.AgentName), "executor") {
							lastPlanExecuteExecutor = UnwrapPlanExecuteUserText(s)
						}
					}
				}
				if subAssistantBuf.Len() > 0 && progress != nil {
					if s := strings.TrimSpace(subAssistantBuf.String()); s != "" {
						if subReplyStreamID != "" {
							progress("eino_agent_reply_stream_end", s, map[string]interface{}{
								"streamId":       subReplyStreamID,
								"einoAgent":      ev.AgentName,
								"einoRole":       "sub",
								"conversationId": conversationID,
								"source":         "eino",
							})
						} else {
							progress("eino_agent_reply", s, map[string]interface{}{
								"conversationId": conversationID,
								"einoAgent":      ev.AgentName,
								"einoRole":       "sub",
								"source":         "eino",
							})
						}
					}
				}
				var lastToolChunk *schema.Message
				if merged := mergeStreamingToolCallFragments(toolStreamFragments); len(merged) > 0 {
					lastToolChunk = &schema.Message{ToolCalls: merged}
				}
				tryEmitToolCallsOnce(lastToolChunk, ev.AgentName, orchestratorName, conversationID, progress, toolEmitSeen, subAgentToolStep, markPending)
				if streamRecvErr != nil {
					if progress != nil {
						progress("eino_stream_error", streamRecvErr.Error(), map[string]interface{}{
							"conversationId": conversationID,
							"source":         "eino",
							"einoAgent":      ev.AgentName,
							"einoRole":       einoRoleTag(ev.AgentName),
						})
					}
					if retErr := handleRunErr(streamRecvErr); retErr != nil {
						return nil, retErr
					}
				}
				continue
			}

			msg, gerr := mv.GetMessage()
			if gerr != nil || msg == nil {
				continue
			}
			runAccumulatedMsgs = append(runAccumulatedMsgs, msg)
			tryEmitToolCallsOnce(mergeMessageToolCalls(msg), ev.AgentName, orchestratorName, conversationID, progress, toolEmitSeen, subAgentToolStep, markPending)

			if mv.Role == schema.Assistant {
				if progress != nil && strings.TrimSpace(msg.ReasoningContent) != "" {
					progress("thinking", strings.TrimSpace(msg.ReasoningContent), map[string]interface{}{
						"conversationId": conversationID,
						"source":         "eino",
						"einoAgent":      ev.AgentName,
						"einoRole":       einoRoleTag(ev.AgentName),
						"orchestration":  orchMode,
					})
				}
				body := strings.TrimSpace(msg.Content)
				if body != "" {
					if streamsMainAssistant(ev.AgentName) {
						if progress != nil {
							progress("response_start", "", map[string]interface{}{
								"conversationId":     conversationID,
								"mcpExecutionIds":    snapshotMCPIDs(),
								"messageGeneratedBy": "eino:" + ev.AgentName,
								"einoRole":           "orchestrator",
								"einoAgent":          ev.AgentName,
								"orchestration":      orchMode,
							})
							progress("response_delta", body, map[string]interface{}{
								"conversationId":  conversationID,
								"mcpExecutionIds": snapshotMCPIDs(),
								"einoRole":        "orchestrator",
								"einoAgent":       ev.AgentName,
								"orchestration":   orchMode,
							})
						}
						lastAssistant = body
						if orchMode == "plan_execute" && strings.EqualFold(strings.TrimSpace(ev.AgentName), "executor") {
							lastPlanExecuteExecutor = UnwrapPlanExecuteUserText(body)
						}
					} else if progress != nil {
						progress("eino_agent_reply", body, map[string]interface{}{
							"conversationId": conversationID,
							"einoAgent":      ev.AgentName,
							"einoRole":       "sub",
							"source":         "eino",
						})
					}
				}
			}

			if mv.Role == schema.Tool && progress != nil {
				toolName := msg.ToolName
				if toolName == "" {
					toolName = mv.ToolName
				}

				content := msg.Content
				isErr := false
				if strings.HasPrefix(content, einomcp.ToolErrorPrefix) {
					isErr = true
					content = strings.TrimPrefix(content, einomcp.ToolErrorPrefix)
				}

				preview := content
				if len(preview) > 200 {
					preview = preview[:200] + "..."
				}
				data := map[string]interface{}{
					"toolName":       toolName,
					"success":        !isErr,
					"isError":        isErr,
					"result":         content,
					"resultPreview":  preview,
					"conversationId": conversationID,
					"einoAgent":      ev.AgentName,
					"einoRole":       einoRoleTag(ev.AgentName),
					"source":         "eino",
				}
				toolCallID := strings.TrimSpace(msg.ToolCallID)
				if toolCallID == "" {
					if inferred, ok := popNextPendingForAgent(ev.AgentName); ok {
						toolCallID = inferred.ToolCallID
					} else if inferred, ok := popNextPendingForAgent(orchestratorName); ok {
						toolCallID = inferred.ToolCallID
					} else if inferred, ok := popNextPendingForAgent(""); ok {
						toolCallID = inferred.ToolCallID
					} else {
						for id := range pendingByID {
							toolCallID = id
							delete(pendingByID, id)
							break
						}
					}
				} else {
					removePendingByID(toolCallID)
				}
				if toolCallID != "" {
					data["toolCallId"] = toolCallID
				}
				progress("tool_result", fmt.Sprintf("工具结果 (%s)", toolName), data)
			}
		}

	mcpIDsMu.Lock()
	ids := append([]string(nil), *mcpIDs...)
	mcpIDsMu.Unlock()

	histJSON, _ := json.Marshal(lastRunMsgs)
	cleaned := strings.TrimSpace(lastAssistant)
	if orchMode == "plan_execute" {
		if e := strings.TrimSpace(lastPlanExecuteExecutor); e != "" {
			cleaned = e
		} else {
			cleaned = UnwrapPlanExecuteUserText(cleaned)
		}
	}
	cleaned = dedupeRepeatedParagraphs(cleaned, 80)
	cleaned = dedupeParagraphsByLineFingerprint(cleaned, 100)
	// 防止超长响应导致 JSON 序列化慢或 OOM（多代理拼接大量工具输出时可能触发）。
	const maxResponseRunes = 100000
	if rs := []rune(cleaned); len(rs) > maxResponseRunes {
		cleaned = string(rs[:maxResponseRunes]) + "\n\n... (response truncated / 响应已截断)"
	}
	out := &RunResult{
		Response:         cleaned,
		MCPExecutionIDs:  ids,
		LastReActInput:   string(histJSON),
		LastReActOutput:  cleaned,
	}
	if out.Response == "" {
		out.Response = emptyHint
		out.LastReActOutput = out.Response
	}
	return out, nil
}