v

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module cli
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import term
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import strings
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const base_indent_len = 2
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const min_description_indent_len = 20
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const spacing = 2
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fn help_flag(with_abbrev bool) Flag {
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	sabbrev := if with_abbrev { 'h' } else { '' }
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	return Flag{
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		flag:        .bool
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		name:        'help'
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		abbrev:      sabbrev
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		description: 'Prints help information.'
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	}
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}
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fn help_cmd() Command {
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	return Command{
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		name:        'help'
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		usage:       '<command>'
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		description: 'Prints help information.'
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		execute:     print_help_for_command
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	}
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}
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// print_help_for_command outputs the help message of `help_cmd`.
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pub fn print_help_for_command(cmd Command) ! {
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	if cmd.args.len > 0 {
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		for sub_cmd in cmd.commands {
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			if sub_cmd.name == cmd.args[0] {
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				cmd_ := unsafe { &sub_cmd }
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				print(cmd_.help_message())
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				return
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			}
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		}
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		print('Invalid command: ${cmd.args.join(' ')}')
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	} else if cmd.parent != unsafe { nil } {
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		print(cmd.parent.help_message())
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	}
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}
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// help_message returns a generated help message as a `string` for the `Command`.
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pub fn (cmd Command) help_message() string {
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	mut help := ''
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	help += 'Usage: ${cmd.full_name()}'
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	if cmd.flags.len > 0 {
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		help += ' [flags]'
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	}
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	if cmd.commands.len > 0 {
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		help += ' [commands]'
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	}
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	if cmd.usage.len > 0 {
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		help += ' ${cmd.usage}'
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	} else {
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		for i in 0 .. cmd.required_args {
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			help += ' <arg${i}>'
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		}
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	}
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	help += '\n'
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	if cmd.description != '' {
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		help += '\n${cmd.description}\n'
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	}
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	mut abbrev_len := 0
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	mut name_len := min_description_indent_len
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	if cmd.posix_mode {
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		for flag in cmd.flags {
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			if flag.abbrev != '' {
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				abbrev_len = max(abbrev_len, flag.abbrev.len + spacing + 1) // + 1 for '-' in front
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			}
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			name_len = max(name_len, abbrev_len + flag.name.len + spacing + 2) // + 2 for '--' in front
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		}
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		for command in cmd.commands {
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			name_len = max(name_len, command.name.len + spacing)
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		}
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	} else {
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		for flag in cmd.flags {
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			if flag.abbrev != '' {
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				abbrev_len = max(abbrev_len, flag.abbrev.len + spacing + 1) // + 1 for '-' in front
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			}
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			name_len = max(name_len, abbrev_len + flag.name.len + spacing + 1) // + 1 for '-' in front
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		}
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		for command in cmd.commands {
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			name_len = max(name_len, command.name.len + spacing)
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		}
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	}
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	if cmd.flags.len > 0 {
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		help += '\nFlags:\n'
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		for flag in cmd.flags {
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			mut flag_name := ''
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			prefix := if cmd.posix_mode { '--' } else { '-' }
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			if flag.abbrev != '' {
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				abbrev_indent := ' '.repeat(abbrev_len - flag.abbrev.len - 1) // - 1 for '-' in front
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				flag_name = '-${flag.abbrev}${abbrev_indent}${prefix}${flag.name}'
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			} else {
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				abbrev_indent := ' '.repeat(abbrev_len)
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				flag_name = '${abbrev_indent}${prefix}${flag.name}'
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			}
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			mut required := ''
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			if flag.required {
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				required = ' (required)'
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			}
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			base_indent := ' '.repeat(base_indent_len)
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			description_indent := ' '.repeat(name_len - flag_name.len)
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			help += '${base_indent}${flag_name}${description_indent}' +
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				pretty_description(flag.description + required, base_indent_len + name_len) + '\n'
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		}
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	}
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	if cmd.commands.len > 0 {
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		help += '\nCommands:\n'
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		for command in cmd.commands {
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			base_indent := ' '.repeat(base_indent_len)
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			description_indent := ' '.repeat(name_len - command.name.len)
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			help += '${base_indent}${command.name}${description_indent}' +
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				pretty_description(command.description, name_len) + '\n'
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		}
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	}
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	return help
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}
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// pretty_description resizes description text depending on terminal width.
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// Essentially, smart wrap-around
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fn pretty_description(s string, indent_len int) string {
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	width, _ := term.get_terminal_size()
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	// Don't prettify if the terminal is that small, it won't be pretty anyway.
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	if indent_len > width {
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		return s
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	}
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	indent := ' '.repeat(indent_len)
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	chars_per_line := width - indent_len
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	// Give us enough room, better a little bigger than smaller
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	mut acc := strings.new_builder(((s.len / chars_per_line) + 1) * (width + 1))
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	for k, line in s.split('\n') {
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		if k != 0 {
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			acc.write_string('\n${indent}')
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		}
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		mut i := chars_per_line - 2
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		mut j := 0
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		for ; i < line.len; i += chars_per_line - 2 {
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			for j > 0 && line[j] != ` ` {
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				j--
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			}
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			// indent was already done the first iteration
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			if j != 0 {
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				acc.write_string(indent)
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			}
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			acc.writeln(line[j..i].trim_space())
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			j = i
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		}
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		// We need this even though it should never happen
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		if j != 0 {
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			acc.write_string(indent)
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		}
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		acc.write_string(line[j..].trim_space())
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	}
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	return acc.str()
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}
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fn max(a int, b int) int {
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	res := if a > b { a } else { b }
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	return res
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}
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