package tests

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"net/url"
	"path"
	"strings"
	"testing"
	"time"

	apiutils "github.com/fnproject/fn/test/fn-api-tests"
	sdkmodels "github.com/fnproject/fn_go/models"
)

// See fn-test-utils for json response
func getEchoContent(respBytes []byte) (string, error) {

	var respJs map[string]interface{}

	err := json.Unmarshal(respBytes, &respJs)
	if err != nil {
		return "", err
	}

	req, ok := respJs["request"].(map[string]interface{})
	if !ok {
		return "", errors.New("unexpected json: request map")
	}

	echo, ok := req["echoContent"].(string)
	if !ok {
		return "", errors.New("unexpected json: echoContent string")
	}

	return echo, nil
}

// See fn-test-utils for json response
func getConfigContent(key string, respBytes []byte) (string, error) {

	var respJs map[string]interface{}

	err := json.Unmarshal(respBytes, &respJs)
	if err != nil {
		return "", err
	}

	cfg, ok := respJs["config"].(map[string]interface{})
	if !ok {
		return "", errors.New("unexpected json: config map")
	}

	val, ok := cfg[key].(string)
	if !ok {
		return "", fmt.Errorf("unexpected json: %s string", key)
	}

	return val, nil
}

func TestCanExecuteFunction(t *testing.T) {
	s := apiutils.SetupHarness()
	s.GivenAppExists(t, &sdkmodels.App{Name: s.AppName})
	defer s.Cleanup()

	rt := s.BasicRoute()
	rt.Image = "fnproject/fn-test-utils"
	rt.Format = "json"
	rt.Memory = 64
	rt.Type = "sync"

	s.GivenRouteExists(t, s.AppName, rt)

	lb, err := LB()
	if err != nil {
		t.Fatalf("Got unexpected error: %v", err)
	}
	u := url.URL{
		Scheme: "http",
		Host:   lb,
	}
	u.Path = path.Join(u.Path, "r", s.AppName, s.RoutePath)

	body := `{"echoContent": "HelloWorld", "sleepTime": 0, "isDebug": true}`
	content := bytes.NewBuffer([]byte(body))
	output := &bytes.Buffer{}

	resp, err := apiutils.CallFN(s.Context, u.String(), content, output, "POST", []string{})
	if err != nil {
		t.Fatalf("Got unexpected error: %v", err)
	}

	echo, err := getEchoContent(output.Bytes())
	if err != nil || echo != "HelloWorld" {
		t.Fatalf("getEchoContent/HelloWorld check failed on %v", output)
	}

	if resp.StatusCode != http.StatusOK {
		t.Fatalf("StatusCode check failed on %v", resp.StatusCode)
	}

	// Now let's check FN_CHEESE, since LB and runners have override/extension mechanism
	// to insert FN_CHEESE into config
	cheese, err := getConfigContent("FN_CHEESE", output.Bytes())
	if err != nil || cheese != "Tete de Moine" {
		t.Fatalf("getConfigContent/FN_CHEESE check failed (%v) on %v", err, output)
	}
}

func TestCanExecuteBigOutput(t *testing.T) {
	s := apiutils.SetupHarness()
	s.GivenAppExists(t, &sdkmodels.App{Name: s.AppName})
	defer s.Cleanup()

	rt := s.BasicRoute()
	rt.Image = "fnproject/fn-test-utils"
	rt.Format = "json"
	rt.Memory = 64
	rt.Type = "sync"

	s.GivenRouteExists(t, s.AppName, rt)

	lb, err := LB()
	if err != nil {
		t.Fatalf("Got unexpected error: %v", err)
	}
	u := url.URL{
		Scheme: "http",
		Host:   lb,
	}
	u.Path = path.Join(u.Path, "r", s.AppName, s.RoutePath)

	// Approx 5.3MB output
	body := `{"echoContent": "HelloWorld", "sleepTime": 0, "isDebug": true, "trailerRepeat": 410000}`
	content := bytes.NewBuffer([]byte(body))
	output := &bytes.Buffer{}

	resp, err := apiutils.CallFN(s.Context, u.String(), content, output, "POST", []string{})
	if err != nil {
		t.Fatalf("Got unexpected error: %v", err)
	}

	t.Logf("getEchoContent/HelloWorld size %d", len(output.Bytes()))

	echo, err := getEchoContent(output.Bytes())
	if err != nil || echo != "HelloWorld" {
		t.Fatalf("getEchoContent/HelloWorld check failed on %v", output)
	}

	if resp.StatusCode != http.StatusOK {
		t.Fatalf("StatusCode check failed on %v", resp.StatusCode)
	}
}

func TestCanExecuteTooBigOutput(t *testing.T) {
	s := apiutils.SetupHarness()
	s.GivenAppExists(t, &sdkmodels.App{Name: s.AppName})
	defer s.Cleanup()

	rt := s.BasicRoute()
	rt.Image = "fnproject/fn-test-utils"
	rt.Format = "json"
	rt.Memory = 64
	rt.Type = "sync"

	s.GivenRouteExists(t, s.AppName, rt)

	lb, err := LB()
	if err != nil {
		t.Fatalf("Got unexpected error: %v", err)
	}
	u := url.URL{
		Scheme: "http",
		Host:   lb,
	}
	u.Path = path.Join(u.Path, "r", s.AppName, s.RoutePath)

	// > 6MB output
	body := `{"echoContent": "HelloWorld", "sleepTime": 0, "isDebug": true, "trailerRepeat": 600000}`
	content := bytes.NewBuffer([]byte(body))
	output := &bytes.Buffer{}

	resp, err := apiutils.CallFN(s.Context, u.String(), content, output, "POST", []string{})
	if err != nil {
		t.Fatalf("Got unexpected error: %v", err)
	}

	exp := "{\"error\":{\"message\":\"function response too large\"}}\n"
	actual := output.String()

	if !strings.Contains(exp, actual) || len(exp) != len(actual) {
		t.Fatalf("Assertion error.\n\tExpected: %v\n\tActual: %v", exp, output.String())
	}

	if resp.StatusCode != http.StatusBadGateway {
		t.Fatalf("StatusCode check failed on %v", resp.StatusCode)
	}
}

func TestCanExecuteEmptyOutput(t *testing.T) {
	s := apiutils.SetupHarness()
	s.GivenAppExists(t, &sdkmodels.App{Name: s.AppName})
	defer s.Cleanup()

	rt := s.BasicRoute()
	rt.Image = "fnproject/fn-test-utils"
	rt.Format = "json"
	rt.Memory = 64
	rt.Type = "sync"

	s.GivenRouteExists(t, s.AppName, rt)

	lb, err := LB()
	if err != nil {
		t.Fatalf("Got unexpected error: %v", err)
	}
	u := url.URL{
		Scheme: "http",
		Host:   lb,
	}
	u.Path = path.Join(u.Path, "r", s.AppName, s.RoutePath)

	// empty body output
	body := `{"sleepTime": 0, "isDebug": true, "isEmptyBody": true}`
	content := bytes.NewBuffer([]byte(body))
	output := &bytes.Buffer{}

	resp, err := apiutils.CallFN(s.Context, u.String(), content, output, "POST", []string{})
	if err != nil {
		t.Fatalf("Got unexpected error: %v", err)
	}

	actual := output.String()

	if 0 != len(actual) {
		t.Fatalf("Assertion error.\n\tExpected empty\n\tActual: %v", output.String())
	}

	if resp.StatusCode != http.StatusOK {
		t.Fatalf("StatusCode check failed on %v", resp.StatusCode)
	}
}

func TestBasicConcurrentExecution(t *testing.T) {

	s := apiutils.SetupHarness()

	s.GivenAppExists(t, &sdkmodels.App{Name: s.AppName})
	defer s.Cleanup()

	rt := s.BasicRoute()
	rt.Image = "fnproject/fn-test-utils"
	rt.Format = "json"
	rt.Memory = 32
	rt.Type = "sync"

	s.GivenRouteExists(t, s.AppName, rt)

	lb, err := LB()
	if err != nil {
		t.Fatalf("Got unexpected error: %v", err)
	}
	u := url.URL{
		Scheme: "http",
		Host:   lb,
	}
	u.Path = path.Join(u.Path, "r", s.AppName, s.RoutePath)

	results := make(chan error)
	concurrentFuncs := 10
	for i := 0; i < concurrentFuncs; i++ {
		go func() {
			body := `{"echoContent": "HelloWorld", "sleepTime": 0, "isDebug": true}`
			content := bytes.NewBuffer([]byte(body))
			output := &bytes.Buffer{}
			resp, err := apiutils.CallFN(s.Context, u.String(), content, output, "POST", []string{})
			if err != nil {
				results <- fmt.Errorf("Got unexpected error: %v", err)
				return
			}

			echo, err := getEchoContent(output.Bytes())
			if err != nil || echo != "HelloWorld" {
				results <- fmt.Errorf("Assertion error.\n\tActual: %v", output.String())
				return
			}
			if resp.StatusCode != http.StatusOK {
				results <- fmt.Errorf("StatusCode check failed on %v", resp.StatusCode)
				return
			}

			results <- nil
		}()
	}
	for i := 0; i < concurrentFuncs; i++ {
		err := <-results
		if err != nil {
			t.Fatalf("Error in basic concurrency execution test: %v", err)
		}
	}

}

func TestSaturatedSystem(t *testing.T) {

	s := apiutils.SetupHarness()

	// override default 60 secs with shorter.
	s.Cancel()
	s.Context, s.Cancel = context.WithTimeout(context.Background(), 4*time.Second)

	s.GivenAppExists(t, &sdkmodels.App{Name: s.AppName})
	defer s.Cleanup()

	timeout := int32(1)

	rt := s.BasicRoute()
	rt.Image = "fnproject/fn-test-utils"
	rt.Format = "json"
	rt.Timeout = &timeout
	rt.Memory = 300
	rt.Type = "sync"

	s.GivenRouteExists(t, s.AppName, rt)

	lb, err := LB()
	if err != nil {
		t.Fatalf("Got unexpected error: %v", err)
	}
	u := url.URL{
		Scheme: "http",
		Host:   lb,
	}
	u.Path = path.Join(u.Path, "r", s.AppName, s.RoutePath)

	body := `{"echoContent": "HelloWorld", "sleepTime": 0, "isDebug": true}`
	content := bytes.NewBuffer([]byte(body))
	output := &bytes.Buffer{}

	resp, err := apiutils.CallFN(s.Context, u.String(), content, output, "POST", []string{})
	if resp != nil || err == nil || s.Context.Err() == nil {
		t.Fatalf("Expected response: %v err:%v", resp, err)
	}
}