package store

import (
	"sort"
	"strings"
	"sync"
	"time"

	"github.com/tinode/chat/server/store/types"
)

const configCacheTTL = time.Minute

type configCacheEntry[T any] struct {
	value     T
	expiresAt time.Time
}

type configCache[T any] struct {
	mu    sync.RWMutex
	items map[string]configCacheEntry[T]
}

func newConfigCache[T any]() *configCache[T] {
	return &configCache[T]{items: make(map[string]configCacheEntry[T])}
}

func (c *configCache[T]) get(key string) (T, bool) {
	var zero T
	c.mu.RLock()
	entry, ok := c.items[key]
	c.mu.RUnlock()
	if !ok || time.Now().After(entry.expiresAt) {
		return zero, false
	}
	return entry.value, true
}

func (c *configCache[T]) set(key string, value T) {
	c.mu.Lock()
	c.items[key] = configCacheEntry[T]{value: value, expiresAt: time.Now().Add(configCacheTTL)}
	c.mu.Unlock()
}

var (
	tenantByCodeCache       = newConfigCache[*types.Tenant]()
	tenantByIDCache         = newConfigCache[*types.Tenant]()
	registrationSMSCache    = newConfigCache[bool]()
	thirdPartyConfigCache   = newConfigCache[map[string]string]()
	thirdPartyConfigAllKeys = "*"
)

func cloneTenant(t *types.Tenant) *types.Tenant {
	if t == nil {
		return nil
	}
	cp := *t
	return &cp
}

func cloneStringMap(src map[string]string) map[string]string {
	if src == nil {
		return nil
	}
	dst := make(map[string]string, len(src))
	for k, v := range src {
		dst[k] = v
	}
	return dst
}

func thirdPartyCacheKey(group string, keys ...string) string {
	group = strings.TrimSpace(group)
	if len(keys) == 0 {
		return group + ":" + thirdPartyConfigAllKeys
	}
	normalized := make([]string, 0, len(keys))
	for _, key := range keys {
		if key = strings.TrimSpace(key); key != "" {
			normalized = append(normalized, key)
		}
	}
	sort.Strings(normalized)
	return group + ":" + strings.Join(normalized, ",")
}