package commands

import "errors"

type CommandHolder struct {
	Name                  string
	Usage                 string
	Handler               CommandHandler
	Permission            int
	Arguments             map[string]*CommandArgument
	ArgumentCount         int
	RequiredArgumentCount int
}

type CommandArgument struct {
	Index    int
	Name     string
	Required bool
	Type     int
}

func (c *CommandHolder) Call(ctx *CommandContext) {
	ctx.holder = c

	if c.ArgumentCount > 0 {
		// Arguments are cached, construct usage
		if err := c.Validate(ctx); err != nil {
			if err == UsageError {
				ctx.Reply("Usage: " + ctx.Prefix + c.Usage)
			} else {
				ctx.Reply(err.Error())
			}
			return
		}
	}

	// Use a goroutine to avoid any blocking operations
	c.Handler(ctx)
}

var (
	UsageError = errors.New("usage")
)

func (c *CommandHolder) Validate(ctx *CommandContext) error {
	if ctx.ArgumentCount < c.RequiredArgumentCount {
		return UsageError
	}

	var argValue string

	for _, arg := range c.Arguments {
		if ctx.ArgumentCount < arg.Index+1 {
			break
		}

		if !arg.Required {
			continue
		}

		argValue = ctx.Arguments[arg.Index]

		if argValue == "" {
			return errors.New("The " + arg.Name + " argument is required.")
		}
	}

	return nil
}