package logic

import (
	"context"
	"sync"
	"time"

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

	"spark-server/internal/pkg/errs"
)

// Denylist stores revoked JWT ids until their original expiry.
type Denylist interface {
	Has(ctx context.Context, jti string) (bool, error)
	Add(ctx context.Context, jti string, ttl time.Duration) error
}

// MemoryDenylist is process-local. Used in tests and when Redis is not configured.
type MemoryDenylist struct {
	mu    sync.Mutex
	items map[string]int64 // jti → expiry unix nano
}

func NewMemoryDenylist() *MemoryDenylist {
	return &MemoryDenylist{items: make(map[string]int64)}
}

func (d *MemoryDenylist) Has(_ context.Context, jti string) (bool, error) {
	if jti == "" {
		return false, nil
	}
	now := time.Now().UnixNano()
	d.mu.Lock()
	defer d.mu.Unlock()
	exp, ok := d.items[jti]
	if !ok {
		return false, nil
	}
	if now >= exp {
		delete(d.items, jti)
		return false, nil
	}
	return true, nil
}

func (d *MemoryDenylist) Add(_ context.Context, jti string, ttl time.Duration) error {
	if jti == "" || ttl <= 0 {
		return nil
	}
	d.mu.Lock()
	d.items[jti] = time.Now().Add(ttl).UnixNano()
	d.mu.Unlock()
	return nil
}

// RedisDenylist uses SETEX denylist:{jti} with remaining token TTL.
type RedisDenylist struct {
	rdb    *redis.Client
	prefix string
}

func NewRedisDenylist(rdb *redis.Client, prefix string) *RedisDenylist {
	if prefix == "" {
		prefix = "denylist:"
	}
	return &RedisDenylist{rdb: rdb, prefix: prefix}
}

func (d *RedisDenylist) key(jti string) string { return d.prefix + jti }

func (d *RedisDenylist) Has(ctx context.Context, jti string) (bool, error) {
	if d == nil || d.rdb == nil {
		return false, errs.ErrAvailable.WithInnerMsg("jwt denylist redis not ready")
	}
	n, err := d.rdb.Exists(ctx, d.key(jti)).Result()
	if err != nil {
		return false, err
	}
	return n > 0, nil
}

func (d *RedisDenylist) Add(ctx context.Context, jti string, ttl time.Duration) error {
	if d == nil || d.rdb == nil {
		return errs.ErrAvailable.WithInnerMsg("jwt denylist redis not ready")
	}
	if jti == "" || ttl <= 0 {
		return nil
	}
	return d.rdb.Set(ctx, d.key(jti), "1", ttl).Err()
}