package publichttp

import (
	"context"
	"encoding/json"
	"io"
	"net"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestConfigValidate(t *testing.T) {
	t.Parallel()

	base := Config{
		Addr:              ":0",
		ReadHeaderTimeout: time.Second,
		ReadTimeout:       time.Second,
		IdleTimeout:       time.Second,
	}
	require.NoError(t, base.Validate())

	tests := []struct {
		name    string
		mutate  func(*Config)
		wantErr string
	}{
		{name: "empty addr", mutate: func(cfg *Config) { cfg.Addr = "" }, wantErr: "addr must not be empty"},
		{name: "zero header", mutate: func(cfg *Config) { cfg.ReadHeaderTimeout = 0 }, wantErr: "read header timeout"},
		{name: "zero read", mutate: func(cfg *Config) { cfg.ReadTimeout = 0 }, wantErr: "read timeout"},
		{name: "zero idle", mutate: func(cfg *Config) { cfg.IdleTimeout = 0 }, wantErr: "idle timeout"},
	}

	for _, tt := range tests {
		tt := tt
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			cfg := base
			tt.mutate(&cfg)
			err := cfg.Validate()
			require.Error(t, err)
			require.Contains(t, err.Error(), tt.wantErr)
		})
	}
}

func TestHandlerRoutes(t *testing.T) {
	t.Parallel()

	handler := newHandler(Dependencies{}, nil)
	server := httptest.NewServer(handler)
	t.Cleanup(server.Close)

	tests := []struct {
		name           string
		method         string
		path           string
		wantStatus     int
		wantStatusBody string
	}{
		{name: "healthz", method: http.MethodGet, path: HealthzPath, wantStatus: http.StatusOK, wantStatusBody: "ok"},
		{name: "readyz", method: http.MethodGet, path: ReadyzPath, wantStatus: http.StatusOK, wantStatusBody: "ready"},
		{name: "not found", method: http.MethodGet, path: "/nope", wantStatus: http.StatusNotFound},
		{name: "method not allowed", method: http.MethodPost, path: HealthzPath, wantStatus: http.StatusMethodNotAllowed},
	}

	for _, tt := range tests {
		tt := tt
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			req, err := http.NewRequest(tt.method, server.URL+tt.path, nil)
			require.NoError(t, err)

			resp, err := server.Client().Do(req)
			require.NoError(t, err)
			defer resp.Body.Close()

			assert.Equal(t, tt.wantStatus, resp.StatusCode)

			if tt.wantStatusBody != "" {
				body, err := io.ReadAll(resp.Body)
				require.NoError(t, err)

				assert.Equal(t, "application/json; charset=utf-8", resp.Header.Get("Content-Type"))

				var payload statusResponse
				require.NoError(t, json.Unmarshal(body, &payload))
				assert.Equal(t, tt.wantStatusBody, payload.Status)
			}
		})
	}
}

func TestShutdownBeforeRunIsNoop(t *testing.T) {
	t.Parallel()

	server, err := NewServer(Config{
		Addr:              "127.0.0.1:0",
		ReadHeaderTimeout: time.Second,
		ReadTimeout:       time.Second,
		IdleTimeout:       time.Second,
	}, Dependencies{})
	require.NoError(t, err)
	require.NoError(t, server.Shutdown(context.Background()))
}

func TestServerRunAndShutdown(t *testing.T) {
	listener, err := net.Listen("tcp", "127.0.0.1:0")
	require.NoError(t, err)
	addr := listener.Addr().String()
	require.NoError(t, listener.Close())

	server, err := NewServer(Config{
		Addr:              addr,
		ReadHeaderTimeout: time.Second,
		ReadTimeout:       time.Second,
		IdleTimeout:       time.Second,
	}, Dependencies{})
	require.NoError(t, err)

	ctx, cancel := context.WithCancel(context.Background())
	t.Cleanup(cancel)

	runErr := make(chan error, 1)
	go func() {
		runErr <- server.Run(ctx)
	}()

	require.Eventually(t, func() bool {
		return server.Addr() != ""
	}, 2*time.Second, 10*time.Millisecond)

	resp, err := http.Get("http://" + server.Addr() + HealthzPath)
	require.NoError(t, err)
	_ = resp.Body.Close()
	assert.Equal(t, http.StatusOK, resp.StatusCode)

	shutdownCtx, shutdownCancel := context.WithTimeout(context.Background(), 2*time.Second)
	t.Cleanup(shutdownCancel)
	require.NoError(t, server.Shutdown(shutdownCtx))

	select {
	case err := <-runErr:
		require.NoError(t, err)
	case <-time.After(2 * time.Second):
		t.Fatal("server did not stop after shutdown")
	}
}