package storage

import (
	"bytes"
	"crypto/tls"
	"encoding/json"
	"io"
	"net/http"
	"net/http/httptest"
	"net/url"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"testing"
)

// TestClusterStorage_scheme tests the scheme() method returns correct values based on TLS configuration
func TestClusterStorage_scheme(t *testing.T) {
	tests := []struct {
		name      string
		transport http.RoundTripper
		want      string
	}{
		{
			name:      "nil transport returns http",
			transport: nil,
			want:      "http",
		},
		{
			name:      "transport without TLS config returns http",
			transport: &http.Transport{},
			want:      "http",
		},
		{
			name: "transport with TLS config returns https",
			transport: &http.Transport{
				TLSClientConfig: &tls.Config{},
			},
			want: "https",
		},
		{
			name: "transport with InsecureSkipVerify returns http",
			transport: &http.Transport{
				TLSClientConfig: &tls.Config{
					InsecureSkipVerify: true,
				},
			},
			want: "http",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			cs := &ClusterStorage{
				client: &http.Client{
					Transport: tt.transport,
				},
			}
			got := cs.scheme()
			if got != tt.want {
				t.Errorf("ClusterStorage.scheme() = %v, want %v", got, tt.want)
			}

			// Also test that strings.ToUpper(scheme()) works as expected in log statements
			gotUpper := strings.ToUpper(cs.scheme())
			wantUpper := strings.ToUpper(tt.want)
			if gotUpper != wantUpper {
				t.Errorf("strings.ToUpper(ClusterStorage.scheme()) = %v, want %v", gotUpper, wantUpper)
			}
		})
	}
}

func TestClusterStorage_ReadToLocalFile(t *testing.T) {
	expected := []byte("cluster-storage-contents")

	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/clusterStorage/read" {
			w.WriteHeader(http.StatusNotFound)
			return
		}

		resp := Response[[]byte]{
			Code: 0,
			Data: expected,
		}

		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(resp)
	}))
	defer srv.Close()

	u, err := url.Parse(srv.URL)
	if err != nil {
		t.Fatalf("parsing test server URL: %s", err)
	}

	port, err := strconv.Atoi(u.Port())
	if err != nil {
		t.Fatalf("parsing test server port: %s", err)
	}

	cs := &ClusterStorage{
		client: &http.Client{},
		host:   u.Hostname(),
		port:   port,
	}

	destPath := filepath.Join(t.TempDir(), "out.bin")
	if err := cs.ReadToLocalFile("some/path", destPath); err != nil {
		t.Fatalf("ReadToLocalFile failed: %s", err)
	}

	data, err := os.ReadFile(destPath)
	if err != nil {
		t.Fatalf("reading destination file: %s", err)
	}

	if string(data) != string(expected) {
		t.Fatalf("destination file contents mismatch: got %q want %q", string(data), string(expected))
	}
}

func TestClusterStorage_ReadStream(t *testing.T) {
	expected := []byte("cluster-storage-stream-contents")

	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/clusterStorage/read" {
			w.WriteHeader(http.StatusNotFound)
			return
		}

		resp := Response[[]byte]{
			Code: 0,
			Data: expected,
		}

		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(resp)
	}))
	defer srv.Close()

	u, err := url.Parse(srv.URL)
	if err != nil {
		t.Fatalf("parsing test server URL: %s", err)
	}

	port, err := strconv.Atoi(u.Port())
	if err != nil {
		t.Fatalf("parsing test server port: %s", err)
	}

	cs := &ClusterStorage{
		client: &http.Client{},
		host:   u.Hostname(),
		port:   port,
	}

	r, err := cs.ReadStream("some/path")
	if err != nil {
		t.Fatalf("ReadStream failed: %s", err)
	}
	defer r.Close()

	data, err := io.ReadAll(r)
	if err != nil {
		t.Fatalf("reading stream failed: %s", err)
	}

	if string(data) != string(expected) {
		t.Fatalf("stream contents mismatch: got %q want %q", string(data), string(expected))
	}
}

func TestClusterStorage_WriteStream(t *testing.T) {
	writeHandler := func(captured *[]byte) http.HandlerFunc {
		return func(w http.ResponseWriter, r *http.Request) {
			if r.Method != http.MethodPut || r.URL.Path != "/clusterStorage/write" {
				w.WriteHeader(http.StatusNotFound)
				return
			}
			var err error
			*captured, err = io.ReadAll(r.Body)
			if err != nil {
				w.WriteHeader(http.StatusInternalServerError)
				return
			}
			w.WriteHeader(http.StatusOK)
		}
	}

	t.Run("single chunk reaches server and Close returns nil", func(t *testing.T) {
		want := []byte("hello from stream")
		var received []byte

		srv := httptest.NewServer(writeHandler(&received))
		defer srv.Close()

		cs := newClusterStorageFromURL(t, srv.URL)

		w, err := cs.WriteStream("some/path")
		if err != nil {
			t.Fatalf("WriteStream: %s", err)
		}
		if _, err = w.Write(want); err != nil {
			_ = w.Close()
			t.Fatalf("Write: %s", err)
		}
		if err = w.Close(); err != nil {
			t.Fatalf("Close: %s", err)
		}

		// Checking received immediately after Close() proves it is synchronous.
		if !bytes.Equal(received, want) {
			t.Errorf("body mismatch: got %q, want %q", received, want)
		}
	})

	t.Run("multi-chunk write concatenates correctly", func(t *testing.T) {
		chunks := [][]byte{[]byte("alpha"), []byte("beta"), []byte("gamma")}
		want := bytes.Join(chunks, nil)
		var received []byte

		srv := httptest.NewServer(writeHandler(&received))
		defer srv.Close()

		cs := newClusterStorageFromURL(t, srv.URL)

		w, err := cs.WriteStream("some/path")
		if err != nil {
			t.Fatalf("WriteStream: %s", err)
		}
		for _, chunk := range chunks {
			if _, err = w.Write(chunk); err != nil {
				_ = w.Close()
				t.Fatalf("Write: %s", err)
			}
		}
		if err = w.Close(); err != nil {
			t.Fatalf("Close: %s", err)
		}

		if !bytes.Equal(received, want) {
			t.Errorf("body mismatch: got %q, want %q", received, want)
		}
	})

	t.Run("server error propagates through Close", func(t *testing.T) {
		srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			_, _ = io.Copy(io.Discard, r.Body)
			w.WriteHeader(http.StatusInternalServerError)
		}))
		defer srv.Close()

		cs := newClusterStorageFromURL(t, srv.URL)

		w, err := cs.WriteStream("some/path")
		if err != nil {
			t.Fatalf("WriteStream: %s", err)
		}
		_, _ = w.Write([]byte("data"))
		if err = w.Close(); err == nil {
			t.Fatalf("expected error from Close on server error, got nil")
		}
	})
}

// newClusterStorageFromURL constructs a ClusterStorage pointed at the given test server URL.
func newClusterStorageFromURL(t *testing.T, rawURL string) *ClusterStorage {
	t.Helper()
	u, err := url.Parse(rawURL)
	if err != nil {
		t.Fatalf("parsing test server URL: %s", err)
	}
	port, err := strconv.Atoi(u.Port())
	if err != nil {
		t.Fatalf("parsing test server port: %s", err)
	}
	return &ClusterStorage{
		client: &http.Client{},
		host:   u.Hostname(),
		port:   port,
	}
}