package cobra

import (

	"fmt"

	"strings"

)

type PositionalArgs func(cmd *Command, args []string) error

// Legacy arg validation has the following behaviour:

// - root commands with no subcommands can take arbitrary arguments

// - root commands with subcommands will do subcommand validity checking

// - subcommands will always accept arbitrary arguments

func legacyArgs(cmd *Command, args []string) error {

	// no subcommand, always take args

	if !cmd.HasSubCommands() {

		return nil

	}

	// root command with subcommands, do subcommand checking.

	if !cmd.HasParent() && len(args) > 0 {

		return fmt.Errorf("unknown command %q for %q%s", args[0], cmd.CommandPath(), cmd.findSuggestions(args[0]))

	}

	return nil

}

// NoArgs returns an error if any args are included.

func NoArgs(cmd *Command, args []string) error {

	if len(args) > 0 {

		return fmt.Errorf("unknown command %q for %q", args[0], cmd.CommandPath())

	}

	return nil

}

func OnlyValidArgs(cmd *Command, args []string) error {

	if len(cmd.ValidArgs) > 0 {

		// Remove any description that may be included in ValidArgs.

		// A description is following a tab character.

		var validArgs []string

		for _, v := range cmd.ValidArgs {

			validArgs = append(validArgs, strings.Split(v, "\t")[0])

		}

		for _, v := range args {

			if !stringInSlice(v, validArgs) {

				return fmt.Errorf("invalid argument %q for %q%s", v, cmd.CommandPath(), cmd.findSuggestions(args[0]))

			}

		}

	}

	return nil

}

// ArbitraryArgs never returns an error.

func ArbitraryArgs(cmd *Command, args []string) error {

	return nil

}

// MinimumNArgs returns an error if there is not at least N args.

func MinimumNArgs(n int) PositionalArgs {

	return func(cmd *Command, args []string) error {

		if len(args) < n {

			return fmt.Errorf("requires at least %d arg(s), only received %d", n, len(args))

		}

		return nil

	}

}

// MaximumNArgs returns an error if there are more than N args.

func MaximumNArgs(n int) PositionalArgs {

	return func(cmd *Command, args []string) error {

		if len(args) > n {

			return fmt.Errorf("accepts at most %d arg(s), received %d", n, len(args))

		}

		return nil

	}

}

// ExactArgs returns an error if there are not exactly n args.

func ExactArgs(n int) PositionalArgs {

	return func(cmd *Command, args []string) error {

		if len(args) != n {

			return fmt.Errorf("accepts %d arg(s), received %d", n, len(args))

		}

		return nil

	}

}

// RangeArgs returns an error if the number of args is not within the expected range.

func RangeArgs(min int, max int) PositionalArgs {

	return func(cmd *Command, args []string) error {

		if len(args) < min || len(args) > max {

			return fmt.Errorf("accepts between %d and %d arg(s), received %d", min, max, len(args))

		}

		return nil

	}

}

// MatchAll allows combining several PositionalArgs to work in concert.

func MatchAll(pargs ...PositionalArgs) PositionalArgs {

	return func(cmd *Command, args []string) error {

		for _, parg := range pargs {

			if err := parg(cmd, args); err != nil {

				return err

			}

		}

		return nil

	}

}