package httpclient

import (
	"context"
	"encoding/base64"
	"io"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"
)

func TestDoWithRedirect_SameHost(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		switch r.URL.Path {
		case "/start":
			w.Header().Set("Location", "/final")
			w.WriteHeader(http.StatusFound)
		case "/final":
			w.WriteHeader(http.StatusOK)
			w.Write([]byte("ok"))
		default:
			w.WriteHeader(http.StatusNotFound)
		}
	}))
	defer srv.Close()

	c := New(Config{Timeout: 5 * time.Second, MaxResponseBytes: 1024})
	req, err := http.NewRequest(http.MethodGet, srv.URL+"/start", nil)
	if err != nil {
		t.Fatalf("new request: %v", err)
	}
	resp, err := c.DoWithRedirect(context.Background(), req, 5, "127.0.0.1")
	if err != nil {
		t.Fatalf("do with redirect: %v", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		t.Fatalf("status=%d, want 200", resp.StatusCode)
	}
	body, _ := io.ReadAll(resp.Body)
	if string(body) != "ok" {
		t.Fatalf("body=%q, want ok", string(body))
	}
}

func TestDoWithRedirect_CrossHost_PreservesAuth(t *testing.T) {
	srv2 := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		w.Write([]byte(r.Header.Get("Authorization")))
	}))
	defer srv2.Close()

	srv1 := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path == "/start" {
			w.Header().Set("Location", srv2.URL+"/final")
			w.WriteHeader(http.StatusTemporaryRedirect)
			return
		}
		w.WriteHeader(http.StatusNotFound)
	}))
	defer srv1.Close()

	c := New(Config{Timeout: 5 * time.Second, MaxResponseBytes: 1024})
	req, err := http.NewRequest(http.MethodGet, srv1.URL+"/start", nil)
	if err != nil {
		t.Fatalf("new request: %v", err)
	}
	req.SetBasicAuth("u", "p")

	resp, err := c.DoWithRedirect(context.Background(), req, 5, "127.0.0.1")
	if err != nil {
		t.Fatalf("do with redirect: %v", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		t.Fatalf("read body: %v", err)
	}
	want := "Basic " + base64.StdEncoding.EncodeToString([]byte("u:p"))
	if string(body) != want {
		t.Fatalf("body=%q, want %q", string(body), want)
	}
}

func TestDoWithRedirect_MaxLimit(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Location", "/loop")
		w.WriteHeader(http.StatusFound)
	}))
	defer srv.Close()

	c := New(Config{Timeout: 5 * time.Second, MaxResponseBytes: 1024})
	req, _ := http.NewRequest(http.MethodGet, srv.URL+"/loop", nil)
	_, err := c.DoWithRedirect(context.Background(), req, 2, "127.0.0.1")
	if err == nil {
		t.Fatal("expected too many redirects error")
	}
	if !strings.Contains(err.Error(), "too many redirects") {
		t.Fatalf("expected too many redirects, got %v", err)
	}
}

func TestDoWithRedirect_NoLocation(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusFound)
	}))
	defer srv.Close()

	c := New(Config{Timeout: 5 * time.Second, MaxResponseBytes: 1024})
	req, _ := http.NewRequest(http.MethodGet, srv.URL, nil)
	_, err := c.DoWithRedirect(context.Background(), req, 5, "127.0.0.1")
	if err == nil {
		t.Fatal("expected error for missing Location")
	}
	if !strings.Contains(err.Error(), "without Location header") {
		t.Fatalf("expected missing Location error, got %v", err)
	}
}

func TestDoWithRedirect_ZeroDisallows(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Location", "/elsewhere")
		w.WriteHeader(http.StatusFound)
	}))
	defer srv.Close()

	c := New(Config{Timeout: 5 * time.Second, MaxResponseBytes: 1024})
	req, _ := http.NewRequest(http.MethodGet, srv.URL, nil)
	resp, err := c.DoWithRedirect(context.Background(), req, 0, "127.0.0.1")
	if err != nil {
		t.Fatalf("do: %v", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusFound {
		t.Fatalf("status=%d, want 302", resp.StatusCode)
	}
}