Marc Cataford
5006ff3076
* feat: init --add-path to provide env export * docs: mention --add-path in setup docs * chore: version update, 0.0.3
106 lines
2.5 KiB
Go
106 lines
2.5 KiB
Go
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"strings"
|
|
)
|
|
|
|
type Flags struct {
|
|
AddPath bool
|
|
NoCache bool
|
|
Verbose bool
|
|
}
|
|
|
|
// Command definition for CLI subcommands.
|
|
type Command struct {
|
|
Label string
|
|
Handler func([]string, Flags, State) error
|
|
Usage string
|
|
Description string
|
|
}
|
|
|
|
// Represents a CLI invocation.
|
|
// Must be initialized with commands via AddCommand before running
|
|
// with Run.
|
|
type CLI struct {
|
|
// Commands in enumeration order.
|
|
OrderedCommands []string
|
|
// Command metadata entries.
|
|
Commands map[string]Command
|
|
Metadata map[string]string
|
|
}
|
|
|
|
// Registers a command.
|
|
// This specifies a label that is used to route the user input to
|
|
// the right command, a handler that is called when the label is used,
|
|
// and usage/description details that get included in autogenerated help messaging.
|
|
func (c CLI) AddCommand(label string, handler func([]string, Flags, State) error, usage string, description string) CLI {
|
|
if c.Commands == nil {
|
|
c.Commands = map[string]Command{}
|
|
c.OrderedCommands = []string{}
|
|
}
|
|
|
|
c.OrderedCommands = append(c.OrderedCommands, label)
|
|
c.Commands[label] = Command{Label: label, Handler: handler, Usage: usage, Description: description}
|
|
|
|
return c
|
|
}
|
|
|
|
// Executes one of the registered commands if any match the provided
|
|
// user arguments.
|
|
func (c CLI) Run(args []string, currentState State) error {
|
|
if len(args) == 0 {
|
|
c.Help()
|
|
return nil
|
|
}
|
|
|
|
command := args[0]
|
|
|
|
if command == "help" {
|
|
c.Help()
|
|
return nil
|
|
}
|
|
|
|
flags := collectFlags(args)
|
|
return c.Commands[command].Handler(args, flags, currentState)
|
|
}
|
|
|
|
// Prints autogenerated help documentation specifying command usage
|
|
// and descriptions based on registered commands (see: AddCommand).
|
|
func (c CLI) Help() {
|
|
usageStrings := []string{}
|
|
|
|
for _, commandLabel := range c.OrderedCommands {
|
|
command := c.Commands[commandLabel]
|
|
usageStrings = append(usageStrings, fmt.Sprintf("\033[1m%-30s\033[0m%s", command.Usage, command.Description))
|
|
}
|
|
|
|
helpString := fmt.Sprintf(`v: A simple version manager. (v%s)
|
|
---
|
|
%s`, c.Metadata["Version"], strings.Join(usageStrings, "\n"))
|
|
|
|
fmt.Println(helpString)
|
|
}
|
|
|
|
// Traverses input arguments and extracts flags of
|
|
// the form --<flag-label>.
|
|
func collectFlags(args []string) Flags {
|
|
collected := Flags{}
|
|
|
|
for _, arg := range args {
|
|
if !strings.HasPrefix(arg, "--") {
|
|
continue
|
|
}
|
|
|
|
switch arg {
|
|
case "--verbose":
|
|
collected.Verbose = true
|
|
case "--no-cache":
|
|
collected.NoCache = true
|
|
case "--add-path":
|
|
collected.AddPath = true
|
|
}
|
|
}
|
|
|
|
return collected
|
|
}
|