// Copyright 2019 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// Binary runner runs the runtime tests in a Docker container.
package main

import (
	"encoding/csv"
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"sort"
	"strings"
	"testing"
	"time"

	"gvisor.dev/gvisor/runsc/dockerutil"
	"gvisor.dev/gvisor/runsc/testutil"
)

var (
	lang          = flag.String("lang", "", "language runtime to test")
	image         = flag.String("image", "", "docker image with runtime tests")
	blacklistFile = flag.String("blacklist_file", "", "file containing blacklist of tests to exclude, in CSV format with fields: test name, bug id, comment")
)

// Wait time for each test to run.
const timeout = 5 * time.Minute

func main() {
	flag.Parse()
	if *lang == "" || *image == "" {
		fmt.Fprintf(os.Stderr, "lang and image flags must not be empty\n")
		os.Exit(1)
	}

	os.Exit(runTests())
}

// runTests is a helper that is called by main. It exists so that we can run
// defered functions before exiting. It returns an exit code that should be
// passed to os.Exit.
func runTests() int {
	// Get tests to blacklist.
	blacklist, err := getBlacklist()
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error getting blacklist: %s\n", err.Error())
		return 1
	}

	// Create a single docker container that will be used for all tests.
	d := dockerutil.MakeDocker("gvisor-" + *lang)
	defer d.CleanUp()

	// Get a slice of tests to run. This will also start a single Docker
	// container that will be used to run each test. The final test will
	// stop the Docker container.
	tests, err := getTests(d, blacklist)
	if err != nil {
		fmt.Fprintf(os.Stderr, "%s\n", err.Error())
		return 1
	}

	m := testing.MainStart(testDeps{}, tests, nil, nil)
	return m.Run()
}

// getTests returns a slice of tests to run, subject to the shard size and
// index.
func getTests(d dockerutil.Docker, blacklist map[string]struct{}) ([]testing.InternalTest, error) {
	// Pull the image.
	if err := dockerutil.Pull(*image); err != nil {
		return nil, fmt.Errorf("docker pull %q failed: %v", *image, err)
	}

	// Run proctor with --pause flag to keep container alive forever.
	if err := d.Run(*image, "--pause"); err != nil {
		return nil, fmt.Errorf("docker run failed: %v", err)
	}

	// Get a list of all tests in the image.
	list, err := d.Exec("/proctor", "--runtime", *lang, "--list")
	if err != nil {
		return nil, fmt.Errorf("docker exec failed: %v", err)
	}

	// Calculate a subset of tests to run corresponding to the current
	// shard.
	tests := strings.Fields(list)
	sort.Strings(tests)
	begin, end, err := testutil.TestBoundsForShard(len(tests))
	if err != nil {
		return nil, fmt.Errorf("TestsForShard() failed: %v", err)
	}
	log.Printf("Got bounds [%d:%d) for shard out of %d total tests", begin, end, len(tests))
	tests = tests[begin:end]

	var itests []testing.InternalTest
	for _, tc := range tests {
		// Capture tc in this scope.
		tc := tc
		itests = append(itests, testing.InternalTest{
			Name: tc,
			F: func(t *testing.T) {
				// Is the test blacklisted?
				if _, ok := blacklist[tc]; ok {
					t.Skip("SKIP: blacklisted test %q", tc)
				}

				var (
					now    = time.Now()
					done   = make(chan struct{})
					output string
					err    error
				)

				go func() {
					fmt.Printf("RUNNING %s...\n", tc)
					output, err = d.Exec("/proctor", "--runtime", *lang, "--test", tc)
					close(done)
				}()

				select {
				case <-done:
					if err == nil {
						fmt.Printf("PASS: %s (%v)\n\n", tc, time.Since(now))
						return
					}
					t.Errorf("FAIL: %s (%v):\n%s\n", tc, time.Since(now), output)
				case <-time.After(timeout):
					t.Errorf("TIMEOUT: %s (%v):\n%s\n", tc, time.Since(now), output)
				}
			},
		})
	}
	return itests, nil
}

// getBlacklist reads the blacklist file and returns a set of test names to
// exclude.
func getBlacklist() (map[string]struct{}, error) {
	blacklist := make(map[string]struct{})
	if *blacklistFile == "" {
		return blacklist, nil
	}
	file, err := testutil.FindFile(*blacklistFile)
	if err != nil {
		return nil, err
	}
	f, err := os.Open(file)
	if err != nil {
		return nil, err
	}
	defer f.Close()

	r := csv.NewReader(f)

	// First line is header. Skip it.
	if _, err := r.Read(); err != nil {
		return nil, err
	}

	for {
		record, err := r.Read()
		if err == io.EOF {
			break
		}
		if err != nil {
			return nil, err
		}
		blacklist[record[0]] = struct{}{}
	}
	return blacklist, nil
}

// testDeps implements testing.testDeps (an unexported interface), and is
// required to use testing.MainStart.
type testDeps struct{}

func (f testDeps) MatchString(a, b string) (bool, error)       { return a == b, nil }
func (f testDeps) StartCPUProfile(io.Writer) error             { return nil }
func (f testDeps) StopCPUProfile()                             {}
func (f testDeps) WriteProfileTo(string, io.Writer, int) error { return nil }
func (f testDeps) ImportPath() string                          { return "" }
func (f testDeps) StartTestLog(io.Writer)                      {}
func (f testDeps) StopTestLog() error                          { return nil }