package context_handler

import (
	"context"
	"errors"
	"fmt"
	"time"
)

type keyType string

const userKey keyType = "userID"

// WithUserID stores user id in context
func WithUserID(ctx context.Context, userID string) context.Context {
	return context.WithValue(ctx, userKey, userID)
}

// FetchRiwayatKursus simulates fetching course history but respects context deadlines/cancel.
func FetchRiwayatKursus(ctx context.Context) (string, error) {
	// try to read user ID
	uid, _ := ctx.Value(userKey).(string)
	if uid == "" {
		uid = "unknown"
	}

	// simulate work that may take up to 2 seconds
	work := make(chan string, 1)

	go func() {
		// simulate slower work 1.5s
		time.Sleep(1500 * time.Millisecond)
		work <- fmt.Sprintf("history for user %s: [Course-A, Course-B]", uid)
	}()

	select {
	case <-ctx.Done():
		// context timed out or cancelled
		return "", errors.New("fetch cancelled or timed out: " + ctx.Err().Error())
	case res := <-work:
		return res, nil
	}
}