package cache

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"strings"
	"time"

	"github.com/redis/go-redis/v9"

	"wx_service/internal/model"
)

type SessionUserCache struct {
	rc        *redis.Client
	keyPrefix string
	ttl       time.Duration
}

func NewSessionUserCache(rc *redis.Client, keyPrefix string, ttl time.Duration) *SessionUserCache {
	return &SessionUserCache{
		rc:        rc,
		keyPrefix: keyPrefix,
		ttl:       ttl,
	}
}

func (c *SessionUserCache) Get(ctx context.Context, token string) (*model.User, bool, error) {
	if c == nil || c.rc == nil || token == "" {
		return nil, false, nil
	}
	key := c.sessionKey(token)
	val, err := c.rc.Get(ctx, key).Bytes()
	if err != nil {
		if errors.Is(err, redis.Nil) {
			return nil, false, nil
		}
		return nil, false, fmt.Errorf("redis get: %w", err)
	}

	var user model.User
	if err := json.Unmarshal(val, &user); err != nil {
		_ = c.rc.Del(ctx, key).Err()
		return nil, false, nil
	}
	return &user, true, nil
}

func (c *SessionUserCache) Set(ctx context.Context, token string, user *model.User) error {
	if c == nil || c.rc == nil || token == "" || user == nil {
		return nil
	}
	key := c.sessionKey(token)
	body, err := json.Marshal(user)
	if err != nil {
		return fmt.Errorf("marshal user: %w", err)
	}
	if err := c.rc.Set(ctx, key, body, c.ttl).Err(); err != nil {
		return fmt.Errorf("redis set: %w", err)
	}
	return nil
}

func (c *SessionUserCache) sessionKey(token string) string {
	prefix := c.keyPrefix
	if prefix != "" && !strings.HasSuffix(prefix, ":") {
		prefix += ":"
	}
	return prefix + "session_user:" + token
}