package aeusadmin

import (
	"context"
	"time"

	"git.nobla.cn/golang/aeus/pkg/cache"
	"gorm.io/gorm"
)

type (
	CachingFunc func(tx *gorm.DB) (any, error)

	CacheOptions struct {
		db            *gorm.DB
		cache         cache.Cache
		dependSQL     string
		dependArgs    []any
		cacheDuration time.Duration
	}

	CacheOption func(o *CacheOptions)

	cacheEntry struct {
		storeValue   any
		compareValue string
		createdAt    time.Time
		lastChecked  time.Time
	}
)

func WithDepend(s string, args ...any) CacheOption {
	return func(o *CacheOptions) {
		o.dependSQL = s
		o.dependArgs = args
	}
}
func TryCache(ctx context.Context, key string, f CachingFunc, cbs ...CacheOption) (value any, err error) {
	var (
		hasDependValue bool
		dependValue    string
	)
	opts := &CacheOptions{
		cacheDuration: time.Minute * 10,
	}
	for _, cb := range cbs {
		cb(opts)
	}
	//从缓存加载数据
	if value, _, err = opts.cache.Get(ctx, key); err == nil {
		entry := value.(*cacheEntry)
		if opts.dependSQL == "" {
			return entry.storeValue, nil
		}
		//如果频繁访问，不检查依赖
		if time.Since(entry.lastChecked) < time.Millisecond*500 {
			return entry.storeValue, nil
		}
		//对比依赖值
		if err = opts.db.Raw(opts.dependSQL, opts.dependArgs...).Scan(&dependValue).Error; err == nil {
			hasDependValue = true
			if entry.compareValue == dependValue {
				entry.lastChecked = time.Now()
				return entry.storeValue, nil
			} else {
				opts.cache.Delete(ctx, key)
			}
		}
	}
	//从数据库加载数据
	if value, err = f(opts.db.WithContext(ctx)); err == nil {
		if !hasDependValue {
			if err = opts.db.WithContext(ctx).Raw(opts.dependSQL, opts.dependArgs...).Scan(&dependValue).Error; err == nil {
				opts.cache.Put(ctx, key, &cacheEntry{
					compareValue: dependValue,
					storeValue:   value,
					createdAt:    time.Now(),
					lastChecked:  time.Now(),
				}, opts.cacheDuration)
			}
		} else {
			opts.cache.Put(ctx, key, &cacheEntry{
				compareValue: dependValue,
				storeValue:   value,
				createdAt:    time.Now(),
				lastChecked:  time.Now(),
			}, opts.cacheDuration)
		}
		return value, nil
	} else {
		return nil, err
	}
}