// Copyright (c) 2025-2026 Probo Inc <hello@probo.com>.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

package saml

import (
	"fmt"
	"strings"

	"github.com/crewjam/saml"
	"go.probo.inc/probo/pkg/coredata"
	"go.probo.inc/probo/pkg/mail"
)

func extractUserAttributes(assertion *saml.Assertion, config *coredata.SAMLConfiguration) (mail.Addr, string, *coredata.MembershipRole, error) {
	var (
		email    mail.Addr
		fullname string
		role     *coredata.MembershipRole
	)

	if len(assertion.AttributeStatements) == 0 {
		if assertion.Subject != nil && assertion.Subject.NameID != nil {
			email, err := mail.ParseAddr(assertion.Subject.NameID.Value)
			if err != nil {
				return mail.Nil, "", nil, fmt.Errorf("cannot parse email: %w", err)
			}

			fullname = email.String()
			role = nil

			return email, fullname, role, nil
		}

		return mail.Nil, "", nil, fmt.Errorf("no attribute statement and no NameID in assertion")
	}

	emailString, err := extractAttributeValue(assertion, config.AttributeEmail)
	if err != nil {
		if assertion.Subject != nil && assertion.Subject.NameID != nil {
			emailString = assertion.Subject.NameID.Value
		} else {
			return mail.Nil, "", nil, fmt.Errorf("cannot extract email: %w", err)
		}
	}

	email, err = mail.ParseAddr(emailString)
	if err != nil {
		return mail.Nil, "", nil, fmt.Errorf("cannot parse email: %w", err)
	}

	firstname, err := extractAttributeValue(assertion, config.AttributeFirstname)
	if err != nil {
		firstname = ""
	}

	lastname, err := extractAttributeValue(assertion, config.AttributeLastname)
	if err != nil {
		lastname = ""
	}

	if firstname != "" && lastname != "" {
		fullname = strings.TrimSpace(firstname + " " + lastname)
	} else if firstname != "" {
		fullname = firstname
	} else if lastname != "" {
		fullname = lastname
	} else {
		fullname = email.String()
	}

	roleString, err := extractAttributeValue(assertion, config.AttributeRole)
	if err != nil {
		role = nil
	}

	if roleString != "" {
		role = mapSAMLRoleToSystemRole(roleString)
	}

	return email, fullname, role, nil
}

func extractAttributeValue(assertion *saml.Assertion, attributeName string) (string, error) {
	if len(assertion.AttributeStatements) == 0 {
		return "", fmt.Errorf("no attribute statement in assertion")
	}

	for _, statement := range assertion.AttributeStatements {
		for _, attr := range statement.Attributes {
			if attr.Name == attributeName {
				if len(attr.Values) == 0 {
					return "", fmt.Errorf("attribute %q has no values", attributeName)
				}

				return attr.Values[0].Value, nil
			}
		}
	}

	return "", fmt.Errorf("attribute %q not found in assertion", attributeName)
}

func mapSAMLRoleToSystemRole(samlRole string) *coredata.MembershipRole {
	if samlRole != "" && isValidRole(samlRole) {
		role := coredata.MembershipRole(samlRole)
		return &role
	}

	return nil
}

func isValidRole(role string) bool {
	switch role {
	case "OWNER", "ADMIN", "EMPLOYEE", "VIEWER":
		return true
	default:
		return false
	}
}