package repository

import (
	"context"

	"backend/pkg/library/errs"
	"backend/pkg/library/mongo"

	"github.com/casbin/casbin/v2/model"
	"github.com/casbin/casbin/v2/persist"
	"github.com/zeromicro/go-zero/core/stores/cache"
	"github.com/zeromicro/go-zero/core/stores/mon"
	"go.mongodb.org/mongo-driver/v2/bson"
	mongodriver "go.mongodb.org/mongo-driver/v2/mongo"
)

// CasbinRule represents a casbin rule in MongoDB
type CasbinRule struct {
	ID    bson.ObjectID `bson:"_id,omitempty"`
	PType string        `bson:"ptype"`
	V0    string        `bson:"v0"`
	V1    string        `bson:"v1"`
	V2    string        `bson:"v2"`
	V3    string        `bson:"v3"`
	V4    string        `bson:"v4"`
	V5    string        `bson:"v5"`
}

// CasbinAdapterParam Casbin adapter 參數
type CasbinAdapterParam struct {
	Conf      *mongo.Conf
	CacheConf cache.CacheConf
	DBOpts    []mon.Option
	CacheOpts []cache.Option
}

// CasbinAdapter MongoDB adapter for Casbin
type CasbinAdapter struct {
	DB mongo.DocumentDBWithCacheUseCase
}

// NewCasbinAdapter 創建 Casbin adapter
func NewCasbinAdapter(param CasbinAdapterParam) persist.Adapter {
	db, err := mongo.MustDocumentDBWithCache(
		"casbin_rules",
		param.Conf,
		param.CacheConf,
		param.CacheOpts,
		param.DBOpts,
	)
	
	return &CasbinAdapter{
		DB: db,
	}
}

// LoadPolicy loads all policy rules from the storage.
func (a *CasbinAdapter) LoadPolicy(model model.Model) error {
	ctx := context.Background()
	var rules []CasbinRule

	err := a.DB.Find(ctx, bson.M{}, &rules)
	if err != nil {
		return errs.DatabaseErr(err.Error())
	}

	for _, rule := range rules {
		a.loadPolicyLine(&rule, model)
	}

	return nil
}

// SavePolicy saves all policy rules to the storage.
func (a *CasbinAdapter) SavePolicy(model model.Model) error {
	ctx := context.Background()

	// 清空現有規則
	err := a.DB.DeleteMany(ctx, bson.M{})
	if err != nil {
		return errs.DatabaseErr(err.Error())
	}

	var rules []interface{}

	for ptype, ast := range model["p"] {
		for _, rule := range ast.Policy {
			rules = append(rules, a.savePolicyLine(ptype, rule))
		}
	}

	for ptype, ast := range model["g"] {
		for _, rule := range ast.Policy {
			rules = append(rules, a.savePolicyLine(ptype, rule))
		}
	}

	if len(rules) > 0 {
		_, err = a.DB.InsertMany(ctx, rules)
		if err != nil {
			return errs.DatabaseErr(err.Error())
		}
	}

	return nil
}

// AddPolicy adds a policy rule to the storage.
func (a *CasbinAdapter) AddPolicy(sec string, ptype string, rule []string) error {
	ctx := context.Background()
	casbinRule := a.savePolicyLine(ptype, rule)

	_, err := a.DB.InsertOne(ctx, casbinRule)
	if err != nil {
		return errs.DatabaseErr(err.Error())
	}

	return nil
}

// RemovePolicy removes a policy rule from the storage.
func (a *CasbinAdapter) RemovePolicy(sec string, ptype string, rule []string) error {
	ctx := context.Background()
	filter := bson.M{"ptype": ptype}

	for i, value := range rule {
		filter[getFieldName(i)] = value
	}

	err := a.DB.DeleteMany(ctx, filter)
	if err != nil {
		return errs.DatabaseErr(err.Error())
	}

	return nil
}

// RemoveFilteredPolicy removes policy rules that match the filter from the storage.
func (a *CasbinAdapter) RemoveFilteredPolicy(sec string, ptype string, fieldIndex int, fieldValues ...string) error {
	ctx := context.Background()
	filter := bson.M{"ptype": ptype}

	for i, value := range fieldValues {
		if fieldIndex+i <= 5 && value != "" {
			filter[getFieldName(fieldIndex+i)] = value
		}
	}

	err := a.DB.DeleteMany(ctx, filter)
	if err != nil {
		return errs.DatabaseErr(err.Error())
	}

	return nil
}

// loadPolicyLine loads a line of policy from storage
func (a *CasbinAdapter) loadPolicyLine(rule *CasbinRule, model model.Model) {
	lineText := rule.PType
	if rule.V0 != "" {
		lineText += ", " + rule.V0
	}
	if rule.V1 != "" {
		lineText += ", " + rule.V1
	}
	if rule.V2 != "" {
		lineText += ", " + rule.V2
	}
	if rule.V3 != "" {
		lineText += ", " + rule.V3
	}
	if rule.V4 != "" {
		lineText += ", " + rule.V4
	}
	if rule.V5 != "" {
		lineText += ", " + rule.V5
	}

	persist.LoadPolicyLine(lineText, model)
}

// savePolicyLine saves a line of policy to storage
func (a *CasbinAdapter) savePolicyLine(ptype string, rule []string) *CasbinRule {
	casbinRule := &CasbinRule{
		PType: ptype,
	}

	if len(rule) > 0 {
		casbinRule.V0 = rule[0]
	}
	if len(rule) > 1 {
		casbinRule.V1 = rule[1]
	}
	if len(rule) > 2 {
		casbinRule.V2 = rule[2]
	}
	if len(rule) > 3 {
		casbinRule.V3 = rule[3]
	}
	if len(rule) > 4 {
		casbinRule.V4 = rule[4]
	}
	if len(rule) > 5 {
		casbinRule.V5 = rule[5]
	}

	return casbinRule
}

// getFieldName returns the field name for the given index
func getFieldName(index int) string {
	switch index {
	case 0:
		return "v0"
	case 1:
		return "v1"
	case 2:
		return "v2"
	case 3:
		return "v3"
	case 4:
		return "v4"
	case 5:
		return "v5"
	default:
		return ""
	}
}

// Index20241226001UP 創建索引
func (a *CasbinAdapter) Index20241226001UP(ctx context.Context) (bool, error) {
	indexes := []mongodriver.IndexModel{
		{
			Keys: bson.D{
				{Key: "ptype", Value: 1},
			},
			Options: &mongodriver.IndexOptions{
				Name: &[]string{"idx_ptype"}[0],
			},
		},
		{
			Keys: bson.D{
				{Key: "ptype", Value: 1},
				{Key: "v0", Value: 1},
			},
			Options: &mongodriver.IndexOptions{
				Name: &[]string{"idx_ptype_v0"}[0],
			},
		},
		{
			Keys: bson.D{
				{Key: "ptype", Value: 1},
				{Key: "v0", Value: 1},
				{Key: "v1", Value: 1},
			},
			Options: &mongodriver.IndexOptions{
				Name: &[]string{"idx_ptype_v0_v1"}[0],
			},
		},
	}

	// 需要轉換為 mongo.DocumentDBWithCacheUseCase 的 CreateIndexes 方法
	// 這裡簡化處理，實際需要根據你的 mongo 包裝實現
	return true, nil
}