package cert

import (
	"context"
	"crypto/x509"
	"fmt"
	"strings"
	"time"

	sockaddr "github.com/hashicorp/go-sockaddr"
	"github.com/hashicorp/vault/sdk/framework"
	"github.com/hashicorp/vault/sdk/helper/tokenutil"
	"github.com/hashicorp/vault/sdk/logical"
)

func pathListCerts(b *backend) *framework.Path {
	return &framework.Path{
		Pattern: "certs/?",

		Callbacks: map[logical.Operation]framework.OperationFunc{
			logical.ListOperation: b.pathCertList,
		},

		HelpSynopsis:    pathCertHelpSyn,
		HelpDescription: pathCertHelpDesc,
	}
}

func pathCerts(b *backend) *framework.Path {
	p := &framework.Path{
		Pattern: "certs/" + framework.GenericNameRegex("name"),
		Fields: map[string]*framework.FieldSchema{
			"name": &framework.FieldSchema{
				Type:        framework.TypeString,
				Description: "The name of the certificate",
			},

			"certificate": &framework.FieldSchema{
				Type: framework.TypeString,
				Description: `The public certificate that should be trusted.
Must be x509 PEM encoded.`,
			},

			"allowed_names": &framework.FieldSchema{
				Type: framework.TypeCommaStringSlice,
				Description: `A comma-separated list of names.
At least one must exist in either the Common Name or SANs. Supports globbing.  
This parameter is deprecated, please use allowed_common_names, allowed_dns_sans, 
allowed_email_sans, allowed_uri_sans.`,
			},

			"allowed_common_names": &framework.FieldSchema{
				Type: framework.TypeCommaStringSlice,
				Description: `A comma-separated list of names.
At least one must exist in the Common Name. Supports globbing.`,
			},

			"allowed_dns_sans": &framework.FieldSchema{
				Type: framework.TypeCommaStringSlice,
				Description: `A comma-separated list of DNS names.
At least one must exist in the SANs. Supports globbing.`,
			},

			"allowed_email_sans": &framework.FieldSchema{
				Type: framework.TypeCommaStringSlice,
				Description: `A comma-separated list of Email Addresses.
At least one must exist in the SANs. Supports globbing.`,
			},

			"allowed_uri_sans": &framework.FieldSchema{
				Type: framework.TypeCommaStringSlice,
				Description: `A comma-separated list of URIs.
At least one must exist in the SANs. Supports globbing.`,
			},

			"allowed_organizational_units": &framework.FieldSchema{
				Type: framework.TypeCommaStringSlice,
				Description: `A comma-separated list of Organizational Units names.
At least one must exist in the OU field.`,
			},

			"required_extensions": &framework.FieldSchema{
				Type: framework.TypeCommaStringSlice,
				Description: `A comma-separated string or array of extensions
formatted as "oid:value". Expects the extension value to be some type of ASN1 encoded string.
All values much match. Supports globbing on "value".`,
			},

			"display_name": &framework.FieldSchema{
				Type: framework.TypeString,
				Description: `The display name to use for clients using this
certificate.`,
			},

			"policies": &framework.FieldSchema{
				Type:        framework.TypeCommaStringSlice,
				Description: tokenutil.DeprecationText("token_policies"),
				Deprecated:  true,
			},

			"lease": &framework.FieldSchema{
				Type:        framework.TypeInt,
				Description: tokenutil.DeprecationText("token_ttl"),
				Deprecated:  true,
			},

			"ttl": &framework.FieldSchema{
				Type:        framework.TypeDurationSecond,
				Description: tokenutil.DeprecationText("token_ttl"),
				Deprecated:  true,
			},

			"max_ttl": &framework.FieldSchema{
				Type:        framework.TypeDurationSecond,
				Description: tokenutil.DeprecationText("token_max_ttl"),
				Deprecated:  true,
			},

			"period": &framework.FieldSchema{
				Type:        framework.TypeDurationSecond,
				Description: tokenutil.DeprecationText("token_period"),
				Deprecated:  true,
			},

			"bound_cidrs": &framework.FieldSchema{
				Type:        framework.TypeCommaStringSlice,
				Description: tokenutil.DeprecationText("token_bound_cidrs"),
				Deprecated:  true,
			},
		},

		Callbacks: map[logical.Operation]framework.OperationFunc{
			logical.DeleteOperation: b.pathCertDelete,
			logical.ReadOperation:   b.pathCertRead,
			logical.UpdateOperation: b.pathCertWrite,
		},

		HelpSynopsis:    pathCertHelpSyn,
		HelpDescription: pathCertHelpDesc,
	}

	tokenutil.AddTokenFields(p.Fields)
	return p
}

func (b *backend) Cert(ctx context.Context, s logical.Storage, n string) (*CertEntry, error) {
	entry, err := s.Get(ctx, "cert/"+strings.ToLower(n))
	if err != nil {
		return nil, err
	}
	if entry == nil {
		return nil, nil
	}

	var result CertEntry
	if err := entry.DecodeJSON(&result); err != nil {
		return nil, err
	}

	if result.TokenTTL == 0 && result.TTL > 0 {
		result.TokenTTL = result.TTL
	}
	if result.TokenMaxTTL == 0 && result.MaxTTL > 0 {
		result.TokenMaxTTL = result.MaxTTL
	}
	if result.TokenPeriod == 0 && result.Period > 0 {
		result.TokenPeriod = result.Period
	}
	if len(result.TokenPolicies) == 0 && len(result.Policies) > 0 {
		result.TokenPolicies = result.Policies
	}
	if len(result.TokenBoundCIDRs) == 0 && len(result.BoundCIDRs) > 0 {
		result.TokenBoundCIDRs = result.BoundCIDRs
	}

	return &result, nil
}

func (b *backend) pathCertDelete(ctx context.Context, req *logical.Request, d *framework.FieldData) (*logical.Response, error) {
	err := req.Storage.Delete(ctx, "cert/"+strings.ToLower(d.Get("name").(string)))
	if err != nil {
		return nil, err
	}
	return nil, nil
}

func (b *backend) pathCertList(ctx context.Context, req *logical.Request, d *framework.FieldData) (*logical.Response, error) {
	certs, err := req.Storage.List(ctx, "cert/")
	if err != nil {
		return nil, err
	}
	return logical.ListResponse(certs), nil
}

func (b *backend) pathCertRead(ctx context.Context, req *logical.Request, d *framework.FieldData) (*logical.Response, error) {
	cert, err := b.Cert(ctx, req.Storage, strings.ToLower(d.Get("name").(string)))
	if err != nil {
		return nil, err
	}
	if cert == nil {
		return nil, nil
	}

	data := map[string]interface{}{
		"certificate":                  cert.Certificate,
		"display_name":                 cert.DisplayName,
		"allowed_names":                cert.AllowedNames,
		"allowed_common_names":         cert.AllowedCommonNames,
		"allowed_dns_sans":             cert.AllowedDNSSANs,
		"allowed_email_sans":           cert.AllowedEmailSANs,
		"allowed_uri_sans":             cert.AllowedURISANs,
		"allowed_organizational_units": cert.AllowedOrganizationalUnits,
		"required_extensions":          cert.RequiredExtensions,
	}
	cert.PopulateTokenData(data)

	if cert.TTL > 0 {
		data["ttl"] = int64(cert.TTL.Seconds())
	}
	if cert.MaxTTL > 0 {
		data["max_ttl"] = int64(cert.MaxTTL.Seconds())
	}
	if cert.Period > 0 {
		data["period"] = int64(cert.Period.Seconds())
	}
	if len(cert.Policies) > 0 {
		data["policies"] = data["token_policies"]
	}
	if len(cert.BoundCIDRs) > 0 {
		data["bound_cidrs"] = data["token_bound_cidrs"]
	}

	return &logical.Response{
		Data: data,
	}, nil
}

func (b *backend) pathCertWrite(ctx context.Context, req *logical.Request, d *framework.FieldData) (*logical.Response, error) {
	name := strings.ToLower(d.Get("name").(string))

	cert, err := b.Cert(ctx, req.Storage, name)
	if err != nil {
		return nil, err
	}

	if cert == nil {
		cert = &CertEntry{
			Name: name,
		}
	}

	// Get non tokenutil fields
	if certificateRaw, ok := d.GetOk("certificate"); ok {
		cert.Certificate = certificateRaw.(string)
	}
	if displayNameRaw, ok := d.GetOk("display_name"); ok {
		cert.DisplayName = displayNameRaw.(string)
	}
	if allowedNamesRaw, ok := d.GetOk("allowed_names"); ok {
		cert.AllowedNames = allowedNamesRaw.([]string)
	}
	if allowedCommonNamesRaw, ok := d.GetOk("allowed_common_names"); ok {
		cert.AllowedCommonNames = allowedCommonNamesRaw.([]string)
	}
	if allowedDNSSANsRaw, ok := d.GetOk("allowed_dns_sans"); ok {
		cert.AllowedDNSSANs = allowedDNSSANsRaw.([]string)
	}
	if allowedEmailSANsRaw, ok := d.GetOk("allowed_email_sans"); ok {
		cert.AllowedEmailSANs = allowedEmailSANsRaw.([]string)
	}
	if allowedURISANsRaw, ok := d.GetOk("allowed_uri_sans"); ok {
		cert.AllowedURISANs = allowedURISANsRaw.([]string)
	}
	if allowedOrganizationalUnitsRaw, ok := d.GetOk("allowed_organizational_units"); ok {
		cert.AllowedOrganizationalUnits = allowedOrganizationalUnitsRaw.([]string)
	}
	if requiredExtensionsRaw, ok := d.GetOk("required_extensions"); ok {
		cert.RequiredExtensions = requiredExtensionsRaw.([]string)
	}

	// Get tokenutil fields
	if err := cert.ParseTokenFields(req, d); err != nil {
		return logical.ErrorResponse(err.Error()), logical.ErrInvalidRequest
	}

	// Handle upgrade cases
	{
		if err := tokenutil.UpgradeValue(d, "policies", "token_policies", &cert.Policies, &cert.TokenPolicies); err != nil {
			return logical.ErrorResponse(err.Error()), nil
		}

		if err := tokenutil.UpgradeValue(d, "ttl", "token_ttl", &cert.TTL, &cert.TokenTTL); err != nil {
			return logical.ErrorResponse(err.Error()), nil
		}
		// Special case here for old lease value
		_, ok := d.GetOk("token_ttl")
		if !ok {
			_, ok = d.GetOk("ttl")
			if !ok {
				ttlRaw, ok := d.GetOk("lease")
				if ok {
					cert.TTL = time.Duration(ttlRaw.(int)) * time.Second
					cert.TokenTTL = cert.TTL
				}
			}
		}

		if err := tokenutil.UpgradeValue(d, "max_ttl", "token_max_ttl", &cert.MaxTTL, &cert.TokenMaxTTL); err != nil {
			return logical.ErrorResponse(err.Error()), nil
		}

		if err := tokenutil.UpgradeValue(d, "period", "token_period", &cert.Period, &cert.TokenPeriod); err != nil {
			return logical.ErrorResponse(err.Error()), nil
		}

		if err := tokenutil.UpgradeValue(d, "bound_cidrs", "token_bound_cidrs", &cert.BoundCIDRs, &cert.TokenBoundCIDRs); err != nil {
			return logical.ErrorResponse(err.Error()), nil
		}
	}

	var resp logical.Response

	systemDefaultTTL := b.System().DefaultLeaseTTL()
	if cert.TokenTTL > systemDefaultTTL {
		resp.AddWarning(fmt.Sprintf("Given ttl of %d seconds is greater than current mount/system default of %d seconds", cert.TokenTTL/time.Second, systemDefaultTTL/time.Second))
	}
	systemMaxTTL := b.System().MaxLeaseTTL()
	if cert.TokenMaxTTL > systemMaxTTL {
		resp.AddWarning(fmt.Sprintf("Given max_ttl of %d seconds is greater than current mount/system default of %d seconds", cert.TokenMaxTTL/time.Second, systemMaxTTL/time.Second))
	}
	if cert.TokenMaxTTL != 0 && cert.TokenTTL > cert.TokenMaxTTL {
		return logical.ErrorResponse("ttl should be shorter than max_ttl"), nil
	}
	if cert.TokenPeriod > systemMaxTTL {
		resp.AddWarning(fmt.Sprintf("Given period of %d seconds is greater than the backend's maximum TTL of %d seconds", cert.TokenPeriod/time.Second, systemMaxTTL/time.Second))
	}

	// Default the display name to the certificate name if not given
	if cert.DisplayName == "" {
		cert.DisplayName = name
	}

	parsed := parsePEM([]byte(cert.Certificate))
	if len(parsed) == 0 {
		return logical.ErrorResponse("failed to parse certificate"), nil
	}

	// If the certificate is not a CA cert, then ensure that x509.ExtKeyUsageClientAuth is set
	if !parsed[0].IsCA && parsed[0].ExtKeyUsage != nil {
		var clientAuth bool
		for _, usage := range parsed[0].ExtKeyUsage {
			if usage == x509.ExtKeyUsageClientAuth || usage == x509.ExtKeyUsageAny {
				clientAuth = true
				break
			}
		}
		if !clientAuth {
			return logical.ErrorResponse("non-CA certificates should have TLS client authentication set as an extended key usage"), nil
		}
	}

	// Store it
	entry, err := logical.StorageEntryJSON("cert/"+name, cert)
	if err != nil {
		return nil, err
	}
	if err := req.Storage.Put(ctx, entry); err != nil {
		return nil, err
	}

	if len(resp.Warnings) == 0 {
		return nil, nil
	}

	return &resp, nil
}

type CertEntry struct {
	tokenutil.TokenParams

	Name                       string
	Certificate                string
	DisplayName                string
	Policies                   []string
	TTL                        time.Duration
	MaxTTL                     time.Duration
	Period                     time.Duration
	AllowedNames               []string
	AllowedCommonNames         []string
	AllowedDNSSANs             []string
	AllowedEmailSANs           []string
	AllowedURISANs             []string
	AllowedOrganizationalUnits []string
	RequiredExtensions         []string
	BoundCIDRs                 []*sockaddr.SockAddrMarshaler
}

const pathCertHelpSyn = `
Manage trusted certificates used for authentication.
`

const pathCertHelpDesc = `
This endpoint allows you to create, read, update, and delete trusted certificates
that are allowed to authenticate.

Deleting a certificate will not revoke auth for prior authenticated connections.
To do this, do a revoke on "login". If you don't need to revoke login immediately,
then the next renew will cause the lease to expire.
`