package middleware

import (
	"context"
	"net/http"
	"time"
)

// TimeoutMiddleware is necessary in addition to http.Server's ReadTimeout,
// WriteTimeout, and IdleTimeout. http.Server's timeouts are network-level
// timeouts, while this middleware's timeout is at the application level.
// TODO: Verify this statement

// TimeoutMiddleware sets a timeout for each request
func TimeoutMiddleware(duration time.Duration) Middleware {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			// Create a context with a timeout
			ctx, cancel := context.WithTimeout(r.Context(), duration)
			defer cancel()

			// Create a channel to signal when the request is done
			done := make(chan struct{})

			// Create a new request with the timeout context
			r = r.WithContext(ctx)

			// Use a goroutine to run the next handler
			go func() {
				next.ServeHTTP(w, r)
				close(done)
			}()

			// Wait for the handler to finish or the context to timeout
			select {
			case <-done:
				// Request finished within the timeout
				return
			case <-ctx.Done():
				// Timeout occurred, respond with a timeout error
				http.Error(w, "Request timed out", http.StatusGatewayTimeout)
				return
			}
		})
	}
}