package asterisk

import (
	"errors"
	"fmt"
	"regexp"
	"strings"
	"time"

	"github.com/CyCoreSystems/ari/v5"
)

var dialedRoute = regexp.MustCompile(`^[a-zA-Z0-9]+$`)

// approvedOriginateRequest binds an already-approved Agent instruction to one
// native ARI channel. The Dispatcher, not the Agent, selected the trunk,
// caller and complete dialed number (including any trunk-specific prefix).
func approvedOriginateRequest(executionID, trunkID, dialedCallee, callerID string, answerTimeout time.Duration) (ari.OriginateRequest, error) {
	if !trunkName.MatchString(executionID) || !trunkName.MatchString(trunkID) || !dialedRoute.MatchString(dialedCallee) || strings.TrimSpace(callerID) == "" || strings.ContainsAny(callerID, "\r\n") {
		return ari.OriginateRequest{}, errors.New("approved ARI channel identity or route is incomplete")
	}
	seconds := int(answerTimeout / time.Second)
	if seconds < 1 {
		return ari.OriginateRequest{}, fmt.Errorf("approved ARI answer window is shorter than one second: %s", answerTimeout)
	}
	return ari.OriginateRequest{
		ChannelID: executionID, Endpoint: "PJSIP/" + dialedCallee + "@" + trunkID,
		CallerID: callerID, App: "go-sip-agent", Timeout: seconds,
	}, nil
}