Add contest parsing support

Author: Eroui

commands/parse.go

@@ -4,10 +4,13 @@ import (
 	"bytes"
 	"context"
 	json2 "encoding/json"
+	"errors"
+	"fmt"
 	"io/ioutil"
 	"net/http"
 	"os"
 	"path"
+	"strconv"
 	"strings"
 	template2 "text/template"
 	"time"
@@ -20,6 +23,8 @@ import (
 
 const listenAddr = ":4243"
 
+var TaskExistsError = errors.New("Task already exists, creation skipped!")
+
 // Serialize task into a JSON string.
 func SerializeTask(meta EgorMeta) (string, error) {
 	var buffer bytes.Buffer
@@ -33,6 +38,9 @@ func SerializeTask(meta EgorMeta) (string, error) {
 func CreateDirectoryStructure(task Task, config Config, rootDir string, context *cli.Context) (string, error) {
 	taskDir := path.Join(rootDir, task.Name)
 	if err := os.Mkdir(taskDir, 0777); err != nil {
+		if os.IsExist(err) {
+			return "", TaskExistsError
+		}
 		return "", err
 	}
 	if err := os.Chdir(taskDir); err != nil {
@@ -128,8 +136,42 @@ func createWebServer(quit chan<- string) *http.Server {
 	}
 }
 
-func waitForShutDown(server *http.Server, done chan<- string, quit <-chan string) {
-	content := <-quit
+func waitForShutDown(server *http.Server, done chan<- string, quit <-chan string, problemsCount int) {
+
+	readProblems := func() <-chan string {
+		results := make(chan string, problemsCount)
+		defer close(results)
+		has := false
+		for i := 0; i < problemsCount; i++ {
+			if has {
+				select {
+				case content := <-quit:
+					results <- content
+				case <-time.After(5 * time.Second):
+					fmt.Println("Timed Out!")
+					return results
+				}
+			} else {
+				content := <-quit
+				results <- content
+				has = true
+			}
+
+		}
+		return results
+	}
+
+	consumeProblems := func(results <-chan string) {
+		defer close(done)
+		for result := range results {
+			done <- result
+		}
+	}
+
+	problems := readProblems()
+	consumeProblems(problems)
+
+	color.Green("Received data from CHelper companion")
 	color.Magenta("Shutting down the server")
 
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
@@ -140,30 +182,34 @@ func waitForShutDown(server *http.Server, done chan<- string, quit <-chan string
 	if err := server.Shutdown(ctx); err != nil {
 		color.Red("Could not shutdown the server")
 	}
-	done <- content
+
+	color.Green("Server stopped")
 }
 
 func ParseAction(context *cli.Context) error {
-	msgReceiveChannel := make(chan string, 1)
-	msgReadChannel := make(chan string, 1)
+	problemsCount := 1
+
+	if context.Bool("contest") && context.NArg() > 0 {
+		count, err := strconv.Atoi(context.Args().Get(0))
+		if err != nil {
+			color.Red(fmt.Sprintf("Cannot parse problems count = '%s', a number required!", context.Args().Get(0)))
+			return fmt.Errorf("Failed to parse test id = %s", context.Args().Get(0))
+		}
+		problemsCount = count
+	}
+
+	msgReceiveChannel := make(chan string, problemsCount)
+	msgReadChannel := make(chan string, problemsCount)
 
 	server := createWebServer(msgReadChannel)
 
-	go waitForShutDown(server, msgReceiveChannel, msgReadChannel)
+	go waitForShutDown(server, msgReceiveChannel, msgReadChannel, problemsCount)
 
 	color.Green("Starting the server on %s\n", listenAddr)
 	if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
 		color.Red("Could not listen on %s, %v\n", listenAddr, err)
 	}
-	json := <-msgReceiveChannel
-	color.Green("Server stopped")
-	color.Green("Received data from CHelper companion")
-	// first line contains a json string
-	lines := strings.Split(json, "\n")
-	task, err := extractTaskFromJson(lines[1])
-	if err != nil {
-		return err
-	}
+
 	config, err := LoadDefaultConfiguration()
 	if err != nil {
 		return err
@@ -172,12 +218,29 @@ func ParseAction(context *cli.Context) error {
 	if err != nil {
 		return err
 	}
-	taskDir, err := CreateDirectoryStructure(*task, *config, cwd, context)
-	if err != nil {
-		color.Red("Error happened %v", err)
-		return err
+
+	for json := range msgReceiveChannel {
+		// first line contains a json string
+		lines := strings.Split(json, "\n")
+		task, err := extractTaskFromJson(lines[1])
+		if err != nil {
+			return err
+		}
+
+		taskDir, err := CreateDirectoryStructure(*task, *config, cwd, context)
+		if err != nil {
+			if err == TaskExistsError {
+				color.Magenta("Skipping creating task %s as it already exists", task.Name)
+				continue
+			} else {
+				color.Red("Unexpected error happened %s", err.Error())
+				return err
+			}
+		}
+
+		color.Green("Created task directory in : %s\n", taskDir)
 	}
-	color.Green("Created task directory in : %s\n", taskDir)
+
 	return nil
 }
 
@@ -202,6 +265,12 @@ var ParseCommand = cli.Command{
 			Aliases: []string{"m", "mul"},
 			Value:   false,
 		},
+		&cli.BoolFlag{
+			Name:    "contest",
+			Usage:   "Indicates if this is a contest to parse",
+			Aliases: []string{"c"},
+			Value:   false,
+		},
 	},
 	Usage:     "Parse task from navigator",
 	UsageText: "egor parse",