package api

import (
	"encoding/json"
	"net/http"
	"strconv"

	"github.com/gorilla/mux"
	"go.temporal.io/sdk/client"
	"github.com/rockliang/poimen/workflows/pkg/db"
	"github.com/rockliang/poimen/workflows/statemachine"
)

// QueryWorkflowGraphRequest matches frontend payload
type QueryWorkflowGraphRequest struct {
	Query            string                 `json:"query"`
	SearchType       string                 `json:"search_type"`
	RelationType     string                 `json:"relation_type"`
	Version          int                    `json:"version"`
	ConfidenceFloor  float64                `json:"confidence_floor"`
	TopK             int                    `json:"top_k"`
	FindPaths        bool                   `json:"find_paths"`
	TargetNodeID     string                 `json:"target_node_id"`
	MaxPathDepth     int                    `json:"max_path_depth"`
	RankingProfile   string                 `json:"ranking_profile"`
	IncludeReasoning bool                   `json:"include_reasoning"`
}

// QueryWorkflowGraphHandler handles POST /workflows/{id}/query
func QueryWorkflowGraphHandler(temporalClient client.Client, dbClient *db.Client) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodPost {
			http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
			return
		}

		workflowID := mux.Vars(r)["id"]
		if workflowID == "" {
			http.Error(w, "Missing workflow ID", http.StatusBadRequest)
			return
		}

		var req QueryWorkflowGraphRequest
		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
			http.Error(w, "Invalid request body", http.StatusBadRequest)
			return
		}

		// Defaults
		if req.SearchType == "" {
			req.SearchType = "edges"
		}
		if req.ConfidenceFloor == 0 {
			req.ConfidenceFloor = 0.5
		}
		if req.TopK == 0 {
			req.TopK = 10
		}
		if req.MaxPathDepth == 0 {
			req.MaxPathDepth = 3
		}
		if req.RankingProfile == "" {
			req.RankingProfile = "default"
		}

		// Get latest version if not specified
		if req.Version == 0 {
			workflow, err := dbClient.GetWorkflow(r.Context(), workflowID)
			if err != nil {
				http.Error(w, "Failed to get workflow", http.StatusInternalServerError)
				return
			}
			req.Version = workflow.Version
		}

		// Start Temporal workflow
		workflowInput := statemachine.WorkflowGraphQueryInput{
			WorkflowID:       workflowID,
			Query:            req.Query,
			SearchType:       req.SearchType,
			RelationType:     req.RelationType,
			Version:          req.Version,
			ConfidenceFloor:  req.ConfidenceFloor,
			TopK:             req.TopK,
			FindPaths:        req.FindPaths,
			TargetNodeID:     req.TargetNodeID,
			MaxPathDepth:     req.MaxPathDepth,
			RankingProfile:   req.RankingProfile,
			IncludeReasoning: req.IncludeReasoning,
		}

		options := client.StartWorkflowOptions{
			ID:       "graph-query-" + workflowID + "-" + strconv.FormatInt(int64(req.Version), 10),
			TaskQueue: "poimen-default",
		}

		// Execute workflow (blocking)
		run, err := temporalClient.ExecuteWorkflow(
			r.Context(),
			options,
			statemachine.WorkflowGraphQuery,
			workflowInput,
		)
		if err != nil {
			http.Error(w, "Failed to start workflow", http.StatusInternalServerError)
			return
		}

		var output statemachine.WorkflowGraphQueryOutput
		if err := run.Get(r.Context(), &output); err != nil {
			http.Error(w, "Workflow execution failed", http.StatusInternalServerError)
			return
		}

		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(output)
	}
}

// GetWorkflowRelationVersionsHandler handles GET /workflows/{id}/relations/{edge_id}/versions
func GetWorkflowRelationVersionsHandler(dbClient *db.Client) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodGet {
			http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
			return
		}

		workflowID := mux.Vars(r)["id"]
		edgeID := mux.Vars(r)["edge_id"]

		if workflowID == "" || edgeID == "" {
			http.Error(w, "Missing parameters", http.StatusBadRequest)
			return
		}

		// Query relation versions from DB
		versions, err := dbClient.GetRelationVersions(r.Context(), workflowID, edgeID)
		if err != nil {
			http.Error(w, "Failed to fetch versions", http.StatusInternalServerError)
			return
		}

		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{
			"workflow_id": workflowID,
			"edge_id":     edgeID,
			"versions":    versions,
			"total_count": len(versions),
		})
	}
}

// RegisterGraphQueryHandlers registers all graph query endpoints
func RegisterGraphQueryHandlers(
	router *mux.Router,
	temporalClient client.Client,
	dbClient *db.Client,
) {
	// Query workflow relations via GraphRAG
	router.HandleFunc("/workflows/{id}/query", QueryWorkflowGraphHandler(temporalClient, dbClient)).Methods("POST")

	// Get relation version history
	router.HandleFunc("/workflows/{id}/relations/{edge_id}/versions", GetWorkflowRelationVersionsHandler(dbClient)).Methods("GET")
}