package llm

import (
	"bytes"
	"io"
	"net/http"
	"testing"
	"time"
)

// Whatever a server streams, reading it does not panic, emits no more
// than it was sent, and gives at most the calls it allows.
func FuzzStream(f *testing.F) {
	f.Add([]byte("data: " + delta(`{"content":"hi"}`) + "\n\ndata: [DONE]\n\n"))
	f.Add([]byte("data: " + delta(`{"tool_calls":[{"index":128,"id":"x","function":{"name":"Read","arguments":"{}"}}]}`) + "\ndata: {\"choices\":[{\"delta\":{},\"finish_reason\":\"stop\"}]}\n"))
	f.Add([]byte("data: {\"choices\":[{\"delta\":{\"content\":\"<think>a</think>b\"}}]}\ndata: {\"error\":{\"message\":\"boom\"}}\n"))
	f.Add([]byte(": keep-alive\n\ndata: {\"choices\":[{\"delta\":{\"tool_calls\":[{\"index\":-1}]}}]}\ndata:[DONE]"))
	f.Fuzz(func(t *testing.T, body []byte) {
		c := New("http://unused", "", "m")
		c.MaxTokens = 1000
		resp := &http.Response{StatusCode: 200, Body: io.NopCloser(bytes.NewReader(body))}
		emitted := 0
		r, _, err := c.readStream(resp, time.Now(), func(text string, _ bool) { emitted += len(text) })
		if err == nil && len(r.Calls) > 129 {
			t.Fatalf("%d calls", len(r.Calls))
		}
		if emitted > len(body) {
			t.Fatalf("emitted %d bytes from a %d-byte stream", emitted, len(body))
		}
	})
}