package sop

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

	"git.iwork-ai.com/xdc/iqudo-top1/internal/access"
	"git.iwork-ai.com/xdc/iqudo-top1/internal/audit"
	"git.iwork-ai.com/xdc/iqudo-top1/internal/auth"
	"git.iwork-ai.com/xdc/iqudo-top1/internal/model"
	"git.iwork-ai.com/xdc/iqudo-top1/internal/response"
	"github.com/gin-gonic/gin"
	"gorm.io/datatypes"
	"gorm.io/gorm"
)

type Handler struct {
	db *gorm.DB
}

func NewHandler(db *gorm.DB) *Handler {
	return &Handler{db: db}
}

type createInput struct {
	Name        string `json:"name" binding:"required,max=128"`
	Description string `json:"description" binding:"max=2000"`
}

type graphInput struct {
	StartNodeKey string      `json:"start_node_key" binding:"required,max=64"`
	Nodes        []nodeInput `json:"nodes" binding:"required,min=1"`
	Edges        []edgeInput `json:"edges"`
}

type nodeInput struct {
	NodeKey   string          `json:"node_key" binding:"required,max=64"`
	Type      string          `json:"type" binding:"required,max=32"`
	Title     string          `json:"title" binding:"required,max=128"`
	Content   string          `json:"content" binding:"max=5000"`
	Config    json.RawMessage `json:"config"`
	PositionX int             `json:"position_x"`
	PositionY int             `json:"position_y"`
}

type edgeInput struct {
	SourceNodeKey string          `json:"source_node_key" binding:"required,max=64"`
	TargetNodeKey string          `json:"target_node_key" binding:"required,max=64"`
	Condition     json.RawMessage `json:"condition"`
	Priority      int             `json:"priority"`
}

type editState struct {
	StartNodeKey string `json:"start_node_key"`
}

func (h *Handler) List(c *gin.Context) {
	p, _ := auth.PrincipalFromContext(c)
	items := make([]model.SOP, 0)
	query := h.db.Table("sops s").Select("s.*").Joins("JOIN scenarios sc ON sc.id = s.scenario_id")
	query = access.ScopeScenarios(query, p, "sc").Where("s.tenant_id = ? AND s.status <> ?", p.TenantID, "archived")
	scenarioID := c.Query("scenario_id")
	if scenarioID == "" {
		scenarioID = c.Param("id")
	}
	if scenarioID != "" {
		query = query.Where("s.scenario_id = ?", scenarioID)
	}
	if err := query.Order("s.updated_at DESC").Scan(&items).Error; err != nil {
		response.Error(c, http.StatusInternalServerError, "QUERY_FAILED", "查询 SOP 失败")
		return
	}
	response.OK(c, gin.H{"items": items, "total": len(items)})
}

func (h *Handler) Create(c *gin.Context) {
	p, _ := auth.PrincipalFromContext(c)
	scenarioID, ok := parseID(c, "id")
	if !ok {
		return
	}
	if !access.CanEditScenario(h.db, p, scenarioID) {
		response.Error(c, http.StatusNotFound, "NOT_FOUND", "场景不存在或不可编辑")
		return
	}
	var scenario model.Scenario
	if err := h.db.Where("id = ? AND tenant_id = ?", scenarioID, p.TenantID).First(&scenario).Error; err != nil {
		response.Error(c, http.StatusNotFound, "NOT_FOUND", "场景不存在")
		return
	}
	var input createInput
	if err := c.ShouldBindJSON(&input); err != nil {
		response.Error(c, http.StatusBadRequest, "INVALID_ARGUMENT", "SOP 信息不完整")
		return
	}
	var item model.SOP
	var version model.SOPVersion
	err := h.db.Transaction(func(tx *gorm.DB) error {
		item = model.SOP{TenantID: p.TenantID, ScenarioID: scenarioID, Name: input.Name, Description: input.Description, Status: "published", CreatedBy: p.UserID}
		if err := tx.Create(&item).Error; err != nil {
			return err
		}
		version = model.SOPVersion{TenantID: p.TenantID, SOPID: item.ID, Version: 1, Status: "published", StartNodeKey: "start", CreatedBy: p.UserID}
		if err := tx.Create(&version).Error; err != nil {
			return err
		}
		nodes := []model.SOPNode{
			{TenantID: p.TenantID, SOPVersionID: version.ID, NodeKey: "start", Type: "start", Title: "开始", Content: "", Config: datatypes.JSON([]byte(`{}`)), PositionX: 0, PositionY: 0},
			{TenantID: p.TenantID, SOPVersionID: version.ID, NodeKey: "opening", Type: "message", Title: "开场", Content: "您好，我先了解一下具体情况。", Config: datatypes.JSON([]byte(`{}`)), PositionX: 0, PositionY: 120},
			{TenantID: p.TenantID, SOPVersionID: version.ID, NodeKey: "finish", Type: "finish", Title: "结束", Content: "本次沟通已完成。", Config: datatypes.JSON([]byte(`{}`)), PositionX: 0, PositionY: 240},
		}
		if err := tx.Create(&nodes).Error; err != nil {
			return err
		}
		edges := []model.SOPEdge{
			{TenantID: p.TenantID, SOPVersionID: version.ID, SourceNodeKey: "start", TargetNodeKey: "opening", Condition: datatypes.JSON([]byte(`{}`)), Priority: 0},
			{TenantID: p.TenantID, SOPVersionID: version.ID, SourceNodeKey: "opening", TargetNodeKey: "finish", Condition: datatypes.JSON([]byte(`{}`)), Priority: 0},
		}
		if err := tx.Create(&edges).Error; err != nil {
			return err
		}
		return tx.Model(&model.Scenario{}).Where("id = ? AND tenant_id = ?", scenarioID, p.TenantID).Update("status", "active").Error
	})
	if err != nil {
		response.Error(c, http.StatusInternalServerError, "CREATE_FAILED", "创建 SOP 失败")
		return
	}
	_ = audit.Record(h.db, p, "create", "sop", item.ID, input)
	response.Created(c, gin.H{"sop": item, "edit": editState{StartNodeKey: version.StartNodeKey}})
}

func (h *Handler) Get(c *gin.Context) {
	p, _ := auth.PrincipalFromContext(c)
	id, ok := parseID(c, "id")
	if !ok {
		return
	}
	if !access.CanViewSOP(h.db, p, id) {
		response.Error(c, http.StatusNotFound, "NOT_FOUND", "SOP 不存在")
		return
	}
	var item model.SOP
	var version model.SOPVersion
	var nodes []model.SOPNode
	var edges []model.SOPEdge
	item, version, nodes, edges, err := h.loadLatest(id, p.TenantID)
	if err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			response.Error(c, http.StatusNotFound, "NOT_FOUND", "SOP 不存在")
		} else {
			response.Error(c, http.StatusInternalServerError, "QUERY_FAILED", "查询 SOP 失败")
		}
		return
	}
	response.OK(c, gin.H{"sop": item, "edit": editState{StartNodeKey: version.StartNodeKey}, "nodes": nodes, "edges": edges})
}

func (h *Handler) SaveGraph(c *gin.Context) {
	p, _ := auth.PrincipalFromContext(c)
	id, ok := parseID(c, "id")
	if !ok {
		return
	}
	if !access.CanEditSOP(h.db, p, id) {
		response.Error(c, http.StatusNotFound, "NOT_FOUND", "SOP 不存在或不可编辑")
		return
	}
	var input graphInput
	if err := c.ShouldBindJSON(&input); err != nil {
		response.Error(c, http.StatusBadRequest, "INVALID_ARGUMENT", "流程配置不完整")
		return
	}
	item, version, _, _, err := h.loadLatest(id, p.TenantID)
	if err != nil {
		response.Error(c, http.StatusNotFound, "NOT_FOUND", "SOP 不存在")
		return
	}
	nodes, edges := toModels(p.TenantID, version.ID, input)
	problems, validationErr := h.validateForPublish(item, input.StartNodeKey, nodes, edges, p.TenantID)
	if validationErr != nil {
		response.Error(c, http.StatusInternalServerError, "VALIDATION_FAILED", "校验流程失败")
		return
	}
	if len(problems) > 0 {
		response.Error(c, http.StatusUnprocessableEntity, "INVALID_GRAPH", problems[0])
		return
	}
	err = h.db.Transaction(func(tx *gorm.DB) error {
		if err := tx.Where("sop_version_id = ?", version.ID).Delete(&model.SOPEdge{}).Error; err != nil {
			return err
		}
		if err := tx.Where("sop_version_id = ?", version.ID).Delete(&model.SOPNode{}).Error; err != nil {
			return err
		}
		if err := tx.Create(&nodes).Error; err != nil {
			return err
		}
		if len(edges) > 0 {
			if err := tx.Create(&edges).Error; err != nil {
				return err
			}
		}
		if err := tx.Model(&model.SOPVersion{}).Where("sop_id = ? AND tenant_id = ? AND id <> ?", id, p.TenantID, version.ID).Update("status", "superseded").Error; err != nil {
			return err
		}
		if err := tx.Model(&version).Updates(map[string]interface{}{"start_node_key": input.StartNodeKey, "status": "published"}).Error; err != nil {
			return err
		}
		if err := tx.Model(&item).Update("status", "published").Error; err != nil {
			return err
		}
		return tx.Model(&model.Scenario{}).Where("id = ? AND tenant_id = ?", item.ScenarioID, p.TenantID).Update("status", "active").Error
	})
	if err != nil {
		response.Error(c, http.StatusInternalServerError, "SAVE_FAILED", "保存流程失败")
		return
	}
	_ = audit.Record(h.db, p, "save_graph", "sop", id, nil)
	h.Get(c)
}

func (h *Handler) Validate(c *gin.Context) {
	p, _ := auth.PrincipalFromContext(c)
	id, ok := parseID(c, "id")
	if !ok {
		return
	}
	if !access.CanViewSOP(h.db, p, id) {
		response.Error(c, http.StatusNotFound, "NOT_FOUND", "SOP 不存在")
		return
	}
	var item model.SOP
	var version model.SOPVersion
	var nodes []model.SOPNode
	var edges []model.SOPEdge
	item, version, nodes, edges, err := h.loadLatest(id, p.TenantID)
	if err != nil {
		response.Error(c, http.StatusNotFound, "NOT_FOUND", "SOP 不存在")
		return
	}
	problems, err := h.validateForPublish(item, version.StartNodeKey, nodes, edges, p.TenantID)
	if err != nil {
		response.Error(c, http.StatusInternalServerError, "VALIDATION_FAILED", "校验流程失败")
		return
	}
	response.OK(c, gin.H{"valid": len(problems) == 0, "problems": problems})
}

func (h *Handler) loadLatest(sopID, tenantID uint64) (model.SOP, model.SOPVersion, []model.SOPNode, []model.SOPEdge, error) {
	var item model.SOP
	if err := h.db.Where("id = ? AND tenant_id = ?", sopID, tenantID).First(&item).Error; err != nil {
		return item, model.SOPVersion{}, nil, nil, err
	}
	var version model.SOPVersion
	if err := h.db.Where("sop_id = ? AND tenant_id = ?", sopID, tenantID).Order("version DESC").First(&version).Error; err != nil {
		return item, version, nil, nil, err
	}
	nodes := make([]model.SOPNode, 0)
	edges := make([]model.SOPEdge, 0)
	if err := h.db.Where("sop_version_id = ? AND tenant_id = ?", version.ID, tenantID).Order("position_y, id").Find(&nodes).Error; err != nil {
		return item, version, nil, nil, err
	}
	if err := h.db.Where("sop_version_id = ? AND tenant_id = ?", version.ID, tenantID).Order("priority, id").Find(&edges).Error; err != nil {
		return item, version, nil, nil, err
	}
	return item, version, nodes, edges, nil
}

func (h *Handler) validateForPublish(item model.SOP, startNodeKey string, nodes []model.SOPNode, edges []model.SOPEdge, tenantID uint64) ([]string, error) {
	fields := make([]model.ScenarioField, 0)
	if err := h.db.Where("scenario_id = ? AND tenant_id = ?", item.ScenarioID, tenantID).Find(&fields).Error; err != nil {
		return nil, err
	}
	var knowledgeItems []model.KnowledgeItem
	if err := h.db.Where("scenario_id = ? AND tenant_id = ?", item.ScenarioID, tenantID).Find(&knowledgeItems).Error; err != nil {
		return nil, err
	}
	var knowledgeRelations []model.KnowledgeRelation
	if err := h.db.Where("scenario_id = ? AND tenant_id = ?", item.ScenarioID, tenantID).Find(&knowledgeRelations).Error; err != nil {
		return nil, err
	}
	return ValidateForPublish(startNodeKey, nodes, edges, ValidationContext{Fields: fields, KnowledgeItems: knowledgeItems, KnowledgeRelations: knowledgeRelations}), nil
}

func toModels(tenantID, versionID uint64, input graphInput) ([]model.SOPNode, []model.SOPEdge) {
	nodes := make([]model.SOPNode, 0, len(input.Nodes))
	for _, item := range input.Nodes {
		config := item.Config
		if len(config) == 0 || !json.Valid(config) {
			config = json.RawMessage(`{}`)
		}
		nodes = append(nodes, model.SOPNode{TenantID: tenantID, SOPVersionID: versionID, NodeKey: item.NodeKey, Type: item.Type, Title: item.Title, Content: item.Content, Config: datatypes.JSON(config), PositionX: item.PositionX, PositionY: item.PositionY})
	}
	edges := make([]model.SOPEdge, 0, len(input.Edges))
	for _, item := range input.Edges {
		condition := item.Condition
		if len(condition) == 0 || !json.Valid(condition) {
			condition = json.RawMessage(`{}`)
		}
		edges = append(edges, model.SOPEdge{TenantID: tenantID, SOPVersionID: versionID, SourceNodeKey: item.SourceNodeKey, TargetNodeKey: item.TargetNodeKey, Condition: datatypes.JSON(condition), Priority: item.Priority})
	}
	return nodes, edges
}

func parseID(c *gin.Context, name string) (uint64, bool) {
	id, err := strconv.ParseUint(c.Param(name), 10, 64)
	if err != nil || id == 0 {
		response.Error(c, http.StatusBadRequest, "INVALID_ID", "资源 ID 不正确")
		return 0, false
	}
	return id, true
}