package command

import (
	"strings"

	"gitea.zaclys.com/bvaudour/gob/format"
	. "gitea.zaclys.com/bvaudour/gob/option"
)

// Parser est une interface pour parser des arguments en ligne de commande.
type Parser interface {
	Parse([]string) Result[[]string]
	IsParsed() bool
	Reset()
}

// Helper est une interface permettant d’afficher l’aide d’une ligne de commande.
type Helper interface {
	Name() string
	Usage() string
}

// Command représente une commande à saisir.
type Command interface {
	Parser
	Helper
	Help() string
	Flags() FlagSet
	Run()
}

// CommandSet est une commande regroupant plusieurs sous-commandes.
type CommandSet interface {
	Parser
	Helper
	Help() string
	Commands() []Command
}

// CommandHelp retourne l’aide sur une commande
func CommandHelp(c Command) string {
	h := c.Help()
	if h != "" {
		return h
	}

	var sb strings.Builder
	sb.WriteString(c.Usage())
	sb.WriteByte('\n')
	sb.WriteString(format.Apply("Usage:", "bold", "underline"))
	sb.WriteByte(' ')
	sb.WriteString(format.Apply(c.Name(), "l_yellow"))
	sb.WriteString(format.Apply(" <options> <args>", "yellow"))
	sb.WriteByte('\n')
	if fs := c.Flags(); fs != nil {
		sb.WriteByte('\n')
		sb.WriteString(fs.Help())
	}

	return sb.String()
}

// CommandSetHelp retourne l’aide sur un ensemble de commandes
func CommandSetHelp(cs CommandSet) string {
	h := cs.Help()
	if h != "" {
		return h
	}

	var sb strings.Builder
	sb.WriteString(cs.Usage())
	sb.WriteByte('\n')
	sb.WriteString(format.Apply("Usage:", "bold", "underline"))
	sb.WriteByte(' ')
	sb.WriteString(format.Apply(cs.Name(), "l_yellow"))
	sb.WriteString(format.Apply(" <cmd> <args>", "yellow"))
	sb.WriteString("\n\n")
	sb.WriteString(format.Apply("Available commands:", "bold", "l_red"))
	sb.WriteByte('\n')

	var (
		cmds    = cs.Commands()
		lines   [][]string
		n       int
		hasHelp bool
	)

	for _, c := range cmds {
		hasHelp = hasHelp || c.Name() == "help"
		cmd, usage := c.Name(), strings.Split(c.Usage(), "\n")
		if len(cmd) > n {
			n = len(cmd)
		}
		for i, l := range usage {
			columns := make([]string, 2)
			if i == 0 {
				columns[0] = cmd
			}
			columns[1] = l
			lines = append(lines, columns)
		}
	}

	if !hasHelp {
		cmd, usage := "help", "Print this help"
		if len(cmd) > n {
			n = len(cmd)
		}
		lines = append(lines, []string{cmd, usage})
	}

	f, c := format.NewAlignment(format.LEFT, n), format.ColorOf("l_yellow")
	for _, columns := range lines {
		cmd, usage := columns[0], columns[1]
		sb.WriteString(format.Tab(2))
		if cmd == "" {
			sb.WriteString(f.Format(cmd))
		} else {
			sb.WriteString(c.Format(f.Format(cmd)))
		}
		sb.WriteString(format.Tab(1))
		sb.WriteString(usage)
		sb.WriteByte('\n')
	}

	return sb.String()
}