package pipeline

import (
	"compress/gzip"
	"context"
	"errors"
	"io"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"

	"evobgp/internal/store"
)

func TestReadCDNBodyLimit(t *testing.T) {
	tests := []struct {
		name  string
		extra int64
		large bool
	}{
		{"exact limit", 0, false},
		{"one byte too large", 1, true},
	}
	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			reader := io.MultiReader(io.LimitReader(strings.NewReader(strings.Repeat("x", cdnBodyLimit)), cdnBodyLimit), strings.NewReader(strings.Repeat("y", int(tc.extra))))
			body, err := ReadCDNBody(reader)
			if tc.large {
				if !errors.Is(err, ErrCDNBodyTooLarge) || body != nil {
					t.Fatalf("body=%d err=%v", len(body), err)
				}
			} else if err != nil || len(body) != cdnBodyLimit {
				t.Fatalf("body=%d err=%v", len(body), err)
			}
		})
	}
}

func TestFetchCDNSourceRowsRejectsOversizedBody(t *testing.T) {
	t.Setenv("EVOBGP_CDN_ALLOW_PRIVATE", "1")
	srv := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		_, _ = io.Copy(w, strings.NewReader(strings.Repeat("x", cdnBodyLimit+1)))
	}))
	defer srv.Close()
	_, err := fetchCDNSourceRows(context.Background(), nil, srv.Client(), "", "", nil,
		&store.CDNSource{ID: "source", URL: srv.URL, SourceKind: "plain"}, modulePrior{}, time.Now())
	if !errors.Is(err, ErrCDNBodyTooLarge) {
		t.Fatalf("oversized CDN source must fail: %v", err)
	}
}

func TestCDNTransportBoundsDecodedGzipBody(t *testing.T) {
	t.Setenv("EVOBGP_CDN_ALLOW_PRIVATE", "1")
	srv := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		w.Header().Set("Content-Encoding", "gzip")
		zw := gzip.NewWriter(w)
		_, _ = io.Copy(zw, io.LimitReader(strings.NewReader(strings.Repeat("x", cdnBodyLimit+1)), cdnBodyLimit+1))
		_ = zw.Close()
	}))
	defer srv.Close()

	client, err := secureCDNClient(srv.Client())
	if err != nil {
		t.Fatal(err)
	}
	resp, err := client.Get(srv.URL)
	if err != nil {
		t.Fatal(err)
	}
	defer func() { _ = resp.Body.Close() }()
	if !resp.Uncompressed {
		t.Fatal("expected net/http gzip decompression")
	}
	if _, err := ReadCDNBody(resp.Body); !errors.Is(err, ErrCDNBodyTooLarge) {
		t.Fatalf("oversized decoded body: %v", err)
	}
}