feat: logger print command fit in term width (#11)

The default logger will check the terminal width and if the command to
be printed is wider than the terminal width, it will be broken up into
multiple lines, similar to a shell command represented on multiple
lines.

README.md

@@ -28,7 +28,7 @@ Additionally many of the tests can provide some example usage.
 
 ### Logging
 
-Cmder logs all commands being run using the specified, using the `Logger` method, logger which implements the [`Logger`](https://github.com/scottames/cmder/blob/master/pkg/log/logger.go#L10-L27) interface.
+Cmder logs all commands being run, using the `Logger` method, which implements the [`Logger`](https://github.com/scottames/cmder/blob/master/pkg/log/logger.go#L10-L27) interface:
 
 ```golang
 type Logger interface {
@@ -43,12 +43,14 @@ type Logger interface {
 }
 ```
 
-By default (if none specified with the `Logger` method) the built-in logger will be used. See Additional `log.Logger*` variables for configuration
+By default (if none specified with the `Cmder.Logger()` method) the built-in [logger](pkg/log/logger.go) will be used. See Additional `log.Logger*` variables for configuration
 options.
 
 Color is disabled by default, but can be enabled by setting either `MAGEFILE_ENABLE_COLOR` or
 `CMDER_ENABLE_COLOR` environment variables to true.
 
+The default logger will check the terminal width and if the command to be printed is wider than the terminal width, it will be broken up into multiple lines, similar to a shell command represented on multiple lines.
+
 ## Contributing
 
 See [CONTRIBUTING.md](CONTRIBUTING.md). Contributors should follow the [Go Community Code of Conduct

go.mod

@@ -6,10 +6,12 @@ require (
 	github.com/go-test/deep v1.1.0
 	github.com/magefile/mage v1.14.0
 	github.com/stretchr/testify v1.8.2
+	golang.org/x/term v0.7.0
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	golang.org/x/sys v0.7.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -14,6 +14,10 @@ github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
 github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+golang.org/x/sys v0.7.0 h1:3jlCCIQZPdOYu1h8BkNvLz8Kgwtae2cagcG/VamtZRU=
+golang.org/x/sys v0.7.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.7.0 h1:BEvjmm5fURWqcfbSKTdpkDXYBrUS1c0m8agp14W48vQ=
+golang.org/x/term v0.7.0/go.mod h1:P32HKFT3hSsZrRxla30E9HqToFYAQPCMs/zFMBUFqPY=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

pkg/log/logger.go

@@ -4,7 +4,10 @@ import (
 	"fmt"
 	"os"
 	"strconv"
+	"strings"
 	"time"
+
+	"golang.org/x/term"
 )
 
 // Logger is a generic logging interface
@@ -176,12 +179,65 @@ func (l logger) Logf(format string, v ...interface{}) {
 	fmt.Printf(s+format+timestamp+"\n", v...)
 }
 
+// splitArgsToNewLine returns a new string formatted as a shell command as if being executed
+// on multiple lines - padding between the [] of the command (slice) to be printed
+func splitArgsToNewLine(s string) string {
+	var result string
+
+	const (
+		bBracket = "["
+		eBracket = "]"
+	)
+
+	newArgs := []string{}
+	args := strings.Split(s, " ")
+
+	for _, w := range args {
+		if strings.HasPrefix(w, bBracket) {
+			w = strings.Replace(w, bBracket, bBracket+"\n\n ", 1)
+		}
+
+		if strings.HasSuffix(w, eBracket) {
+			i := strings.LastIndex(w, eBracket)
+			w = w[:i] + strings.Replace(w[i:], eBracket, "\n\n"+eBracket, 1)
+		}
+
+		if strings.Contains(w, eBracket+string(LoggerColor)) {
+			w = strings.Replace(w, eBracket+string(LoggerColor), "\n\n"+eBracket+string(LoggerColor), 1)
+		}
+
+		if strings.HasPrefix(w, "-") {
+			newArgs = append(newArgs, "\\\n   "+w)
+		} else {
+			newArgs = append(newArgs, w)
+		}
+	}
+
+	result = strings.Join(newArgs, " ")
+
+	return result
+}
+
+// stringLen returns the length of a given string
+func stringLen(s string) int {
+	return len([]rune(s))
+}
+
 // Log implements the Logger interface
 func (l logger) Log(v ...interface{}) {
 	s := l.prependStr()
 	timestamp := l.timestamp(string(LoggerDarkGrey))
+	msg := fmt.Sprintf("%v", v...)
+
+	termWidth, _, err := term.GetSize(int(os.Stdin.Fd()))
+	if err == nil {
+		absLen := stringLen(msg) + stringLen(s) + stringLen(timestamp)
+		if absLen > termWidth {
+			msg = splitArgsToNewLine(msg)
+		}
+	}
 
-	fmt.Printf(s+"%v"+timestamp+"\n", v...)
+	fmt.Printf(s+"%s"+timestamp+"\n", msg)
 }
 
 func (l logger) prependStr() string {