package monitoring

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

func TestLokiClient_QueryRange(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/loki/api/v1/query_range" {
			t.Errorf("unexpected path: %s", r.URL.Path)
		}
		if r.URL.Query().Get("query") != `{job="varlogs"}` {
			t.Errorf("unexpected query param: %s", r.URL.Query().Get("query"))
		}
		if r.URL.Query().Get("direction") != "backward" {
			t.Errorf("unexpected direction: %s", r.URL.Query().Get("direction"))
		}
		if r.URL.Query().Get("limit") != "10" {
			t.Errorf("unexpected limit: %s", r.URL.Query().Get("limit"))
		}

		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{
			"status": "success",
			"data": {
				"resultType": "streams",
				"result": [
					{
						"stream": {"job": "varlogs", "filename": "/var/log/syslog"},
						"values": [
							["1234567890000000000", "line 1"],
							["1234567891000000000", "line 2"]
						]
					}
				]
			}
		}`))
	}))
	defer srv.Close()

	client := NewLokiClient(srv.URL)
	start := time.Unix(0, 1234567890000000000)
	end := time.Unix(0, 1234567899000000000)
	data, err := client.QueryRange(context.Background(), `{job="varlogs"}`, start, end, 10, "backward")
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}

	if data.ResultType != "streams" {
		t.Errorf("expected resultType=streams, got %s", data.ResultType)
	}
	if len(data.Result) != 1 {
		t.Fatalf("expected 1 stream, got %d", len(data.Result))
	}
	if data.Result[0].Stream["job"] != "varlogs" {
		t.Errorf("expected job=varlogs, got %s", data.Result[0].Stream["job"])
	}
	if len(data.Result[0].Values) != 2 {
		t.Fatalf("expected 2 entries, got %d", len(data.Result[0].Values))
	}
	if data.Result[0].Values[0][1] != "line 1" {
		t.Errorf("expected first line='line 1', got %s", data.Result[0].Values[0][1])
	}
}

func TestLokiClient_QueryRangeError(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{
			"status": "error",
			"errorType": "bad_data",
			"error": "invalid LogQL query"
		}`))
	}))
	defer srv.Close()

	client := NewLokiClient(srv.URL)
	_, err := client.QueryRange(context.Background(), "invalid{", time.Now().Add(-time.Hour), time.Now(), 100, "backward")
	if err == nil {
		t.Fatal("expected error, got nil")
	}
	if !contains(err.Error(), "invalid LogQL query") {
		t.Errorf("expected error to contain 'invalid LogQL query', got: %s", err.Error())
	}
}

func TestLokiClient_Labels(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/loki/api/v1/labels" {
			t.Errorf("unexpected path: %s", r.URL.Path)
		}

		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{
			"status": "success",
			"data": ["job", "instance", "filename"]
		}`))
	}))
	defer srv.Close()

	client := NewLokiClient(srv.URL)
	labels, err := client.Labels(context.Background())
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}

	if len(labels) != 3 {
		t.Fatalf("expected 3 labels, got %d", len(labels))
	}
	if labels[0] != "job" {
		t.Errorf("expected first label=job, got %s", labels[0])
	}
}

func TestLokiClient_LabelValues(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/loki/api/v1/label/job/values" {
			t.Errorf("unexpected path: %s, expected /loki/api/v1/label/job/values", r.URL.Path)
		}

		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{
			"status": "success",
			"data": ["varlogs", "nginx", "systemd"]
		}`))
	}))
	defer srv.Close()

	client := NewLokiClient(srv.URL)
	values, err := client.LabelValues(context.Background(), "job")
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}

	if len(values) != 3 {
		t.Fatalf("expected 3 values, got %d", len(values))
	}
	if values[0] != "varlogs" {
		t.Errorf("expected first value=varlogs, got %s", values[0])
	}
}

func TestLokiClient_HTTPError(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusInternalServerError)
		_, _ = w.Write([]byte("internal error"))
	}))
	defer srv.Close()

	client := NewLokiClient(srv.URL)
	_, err := client.QueryRange(context.Background(), `{job="test"}`, time.Now().Add(-time.Hour), time.Now(), 100, "backward")
	if err == nil {
		t.Fatal("expected error, got nil")
	}
	if !contains(err.Error(), "500") {
		t.Errorf("expected error to contain status code, got: %s", err.Error())
	}
}