package repository

import (
	"context"
	"encoding/json"
	"time"

	"code.30cm.net/digimon/app-cloudep-permission-server/pkg/domain"
	"code.30cm.net/digimon/app-cloudep-permission-server/pkg/domain/rbac"
	"code.30cm.net/digimon/app-cloudep-permission-server/pkg/domain/repository"
	"github.com/casbin/casbin/v2/model"
	"github.com/casbin/casbin/v2/persist"
	"github.com/zeromicro/go-zero/core/stores/redis"
)

type RBACAdapterParam struct {
	Redis *redis.Redis
}

type rbacAdapter struct {
	redis *redis.Redis
}

func NewRBACAdapter(param RBACAdapterParam) (repository.RBACAdapter, error) {
	return &rbacAdapter{
		redis: param.Redis,
	}, nil
}

// loadPolicyByString 真正將 Rule 存到 casbin 讓他可以使用的地方
func loadPolicyByString(line rbac.Rule, model model.Model) error {
	text := line.ToString()
	// 雖然是從Redis 來，不過最終還是有一份會存在記憶體當中，這樣做的原因只是不要存第二次
	err := persist.LoadPolicyArray(text, model)
	if err != nil {
		return err
	}

	return nil
}

// LoadPolicy 將檔案從記憶體當中載入本地 Casbin
func (adapter *rbacAdapter) LoadPolicy(model model.Model) error {
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	rk := domain.GetCasbinRuleRedisKey()
	stop, err := adapter.redis.LlenCtx(ctx, rk)
	if err != nil {
		return err
	}

	rules, err := adapter.redis.LrangeCtx(ctx, rk, 0, stop)
	if err != nil {
		return err
	}

	for _, ruleStr := range rules {
		var rule rbac.Rule
		err := json.Unmarshal([]byte(ruleStr), &rule)
		if err != nil {
			return err
		}

		err = loadPolicyByString(rule, model)
		if err != nil {
			return err
		}
	}

	return nil
}

// SavePolicy saves policy to database. 將 Rule 一次就從資料庫中存到 redis 裡面 -> 打API 初始化 Redis 同步的資料
func (adapter *rbacAdapter) SavePolicy(model model.Model) error {
	rk := domain.GetCasbinRuleRedisKey()
	_, err := adapter.redis.Del(rk)
	if err != nil {
		return err
	}

	var texts []string

	for policy, ast := range model["p"] {
		for _, rule := range ast.Policy {
			line := rbac.StringToPolicy(policy, rule)
			text, err := json.Marshal(line)
			if err != nil {
				return err
			}
			texts = append(texts, string(text))
		}
	}

	for policy, ast := range model["g"] {
		for _, rule := range ast.Policy {
			line := rbac.StringToPolicy(policy, rule)
			text, err := json.Marshal(line)
			if err != nil {
				return err
			}
			texts = append(texts, string(text))
		}
	}

	_, err = adapter.redis.Rpush(rk, texts)
	if err != nil {
		return err
	}

	return nil
}

// AddPolicy adds a policy rule to the storage.
func (adapter *rbacAdapter) AddPolicy(_ string, policyType string, rule []string) error {
	policy := rbac.StringToPolicy(policyType, rule)
	text, err := json.Marshal(policy)
	if err != nil {
		return err
	}

	rk := domain.GetCasbinRuleRedisKey()
	_, err = adapter.redis.Rpush(rk, text)
	if err != nil {
		return err
	}

	return nil
}

func (adapter *rbacAdapter) RemovePolicy(_ string, policyType string, rule []string) error {
	policy := rbac.StringToPolicy(policyType, rule)
	text, err := json.Marshal(policy)
	if err != nil {
		return err
	}

	rk := domain.GetCasbinRuleRedisKey()
	_, err = adapter.redis.Lrem(rk, 1, string(text))
	if err != nil {
		return err
	}

	return nil
}

// RemoveFilteredPolicy 沒用到先不實作
func (adapter *rbacAdapter) RemoveFilteredPolicy(_ string, _ string, _ int, _ ...string) error {
	return nil
}