package health

import (
	"database/sql"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"path/filepath"
	"testing"

	"google.golang.org/grpc"

	"git.wntrmute.dev/kyle/mcdsl/db"
)

func TestHandlerHealthy(t *testing.T) {
	database := openTestDB(t)

	handler := Handler(database)
	rec := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/healthz", nil)
	handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
	}

	var body map[string]string
	if err := json.Unmarshal(rec.Body.Bytes(), &body); err != nil {
		t.Fatalf("decode: %v", err)
	}
	if body["status"] != "ok" {
		t.Fatalf("status = %q, want %q", body["status"], "ok")
	}
}

func TestHandlerUnhealthy(t *testing.T) {
	database := openTestDB(t)
	// Close the database to simulate unhealthy state.
	_ = database.Close()

	handler := Handler(database)
	rec := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/healthz", nil)
	handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusServiceUnavailable {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusServiceUnavailable)
	}

	var body map[string]string
	if err := json.Unmarshal(rec.Body.Bytes(), &body); err != nil {
		t.Fatalf("decode: %v", err)
	}
	if body["status"] != "unhealthy" {
		t.Fatalf("status = %q, want %q", body["status"], "unhealthy")
	}
	if body["error"] == "" {
		t.Fatal("expected error message")
	}
}

func TestHandlerContentType(t *testing.T) {
	database := openTestDB(t)

	handler := Handler(database)
	rec := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/healthz", nil)
	handler.ServeHTTP(rec, req)

	if ct := rec.Header().Get("Content-Type"); ct != "application/json" {
		t.Fatalf("Content-Type = %q, want %q", ct, "application/json")
	}
}

func TestRegisterGRPC(t *testing.T) {
	srv := grpc.NewServer()
	// Should not panic.
	RegisterGRPC(srv)

	info := srv.GetServiceInfo()
	if _, ok := info["grpc.health.v1.Health"]; !ok {
		t.Fatal("health service not registered")
	}
}

func openTestDB(t *testing.T) *sql.DB {
	t.Helper()
	dir := t.TempDir()
	path := filepath.Join(dir, "test.db")
	database, err := db.Open(path)
	if err != nil {
		t.Fatalf("db.Open: %v", err)
	}
	t.Cleanup(func() { _ = database.Close() })
	return database
}