cheat/cmd/cheat/cmd_view.go

package main

import (
	"fmt"
	"os"
	"strings"

	"github.com/alecthomas/chroma/quick"
	"github.com/mattn/go-isatty"

	"github.com/cheat/cheat/internal/config"
	"github.com/cheat/cheat/internal/sheets"
)

// cmdView displays a cheatsheet for viewing.
func cmdView(opts map[string]interface{}, conf config.Config) {

	cheatsheet := opts["<cheatsheet>"].(string)

	// load the cheatsheets
	cheatsheets, err := sheets.Load(conf.Cheatpaths)
	if err != nil {
		fmt.Fprintln(os.Stderr, fmt.Sprintf("failed to list cheatsheets: %v", err))
		os.Exit(1)
	}

	// filter cheatcheats by tag if --tag was provided
	if opts["--tag"] != nil {
		cheatsheets = sheets.Filter(
			cheatsheets,
			strings.Split(opts["--tag"].(string), ","),
		)
	}

	// consolidate the cheatsheets found on all paths into a single map of
	// `title` => `sheet` (ie, allow more local cheatsheets to override less
	// local cheatsheets)
	consolidated := sheets.Consolidate(cheatsheets)

	// fail early if the requested cheatsheet does not exist
	sheet, ok := consolidated[cheatsheet]
	if !ok {
		fmt.Printf("No cheatsheet found for '%s'.\n", cheatsheet)
		os.Exit(0)
	}

	// apply colorization if so configured ...
	colorize := conf.Colorize

	// ... or if --colorized were passed ...
	if opts["--colorize"] == true {
		colorize = true
	}

	// ... unless we're outputting to a non-TTY
	if !isatty.IsTerminal(os.Stdout.Fd()) && !isatty.IsCygwinTerminal(os.Stdout.Fd()) {
		colorize = false
	}

	if !colorize {
		fmt.Print(sheet.Text)
		os.Exit(0)
	}

	// otherwise, colorize the output
	// if the syntax was not specified, default to bash
	lex := sheet.Syntax
	if lex == "" {
		lex = "bash"
	}

	// apply syntax highlighting
	err = quick.Highlight(
		os.Stdout,
		sheet.Text,
		lex,
		conf.Formatter,
		conf.Style,
	)

	// if colorization somehow failed, output non-colorized text
	if err != nil {
		fmt.Print(sheet.Text)
	}
}