package pki

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

	"github.com/fatih/structs"
	"github.com/hashicorp/vault/logical"
	"github.com/hashicorp/vault/logical/framework"
)

func pathListRoles(b *backend) *framework.Path {
	return &framework.Path{
		Pattern: "roles/?$",

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

		HelpSynopsis:    pathListRolesHelpSyn,
		HelpDescription: pathListRolesHelpDesc,
	}
}

func pathRoles(b *backend) *framework.Path {
	return &framework.Path{
		Pattern: "roles/" + framework.GenericNameRegex("name"),
		Fields: map[string]*framework.FieldSchema{
			"name": &framework.FieldSchema{
				Type:        framework.TypeString,
				Description: "Name of the role",
			},

			"ttl": &framework.FieldSchema{
				Type:    framework.TypeString,
				Default: "",
				Description: `The lease duration if no specific lease duration is
requested. The lease duration controls the expiration
of certificates issued by this backend. Defaults to
the value of max_ttl.`,
			},

			"max_ttl": &framework.FieldSchema{
				Type:        framework.TypeString,
				Default:     "",
				Description: "The maximum allowed lease duration",
			},

			"allow_localhost": &framework.FieldSchema{
				Type:    framework.TypeBool,
				Default: true,
				Description: `Whether to allow "localhost" as a valid common
name in a request`,
			},

			"allowed_domains": &framework.FieldSchema{
				Type:    framework.TypeString,
				Default: "",
				Description: `If set, clients can request certificates for
subdomains directly beneath these domains, including
the wildcard subdomains. See the documentation for more
information. This parameter accepts a comma-separated list
of domains.`,
			},

			"allow_bare_domains": &framework.FieldSchema{
				Type:    framework.TypeBool,
				Default: false,
				Description: `If set, clients can request certificates
for the base domains themselves, e.g. "example.com".
This is a separate option as in some cases this can
be considered a security threat.`,
			},

			"allow_subdomains": &framework.FieldSchema{
				Type:    framework.TypeBool,
				Default: false,
				Description: `If set, clients can request certificates for
subdomains of the CNs allowed by the other role options,
including wildcard subdomains. See the documentation for
more information.`,
			},

			"allow_any_name": &framework.FieldSchema{
				Type:    framework.TypeBool,
				Default: false,
				Description: `If set, clients can request certificates for
any CN they like. See the documentation for more
information.`,
			},

			"enforce_hostnames": &framework.FieldSchema{
				Type:    framework.TypeBool,
				Default: true,
				Description: `If set, only valid host names are allowed for
CN and SANs. Defaults to true.`,
			},

			"allow_ip_sans": &framework.FieldSchema{
				Type:    framework.TypeBool,
				Default: true,
				Description: `If set, IP Subject Alternative Names are allowed.
Any valid IP is accepted.`,
			},

			"server_flag": &framework.FieldSchema{
				Type:    framework.TypeBool,
				Default: true,
				Description: `If set, certificates are flagged for server auth use.
Defaults to true.`,
			},

			"client_flag": &framework.FieldSchema{
				Type:    framework.TypeBool,
				Default: true,
				Description: `If set, certificates are flagged for client auth use.
Defaults to true.`,
			},

			"code_signing_flag": &framework.FieldSchema{
				Type:    framework.TypeBool,
				Default: false,
				Description: `If set, certificates are flagged for code signing
use. Defaults to false.`,
			},

			"email_protection_flag": &framework.FieldSchema{
				Type:    framework.TypeBool,
				Default: false,
				Description: `If set, certificates are flagged for email
protection use. Defaults to false.`,
			},

			"key_type": &framework.FieldSchema{
				Type:    framework.TypeString,
				Default: "rsa",
				Description: `The type of key to use; defaults to RSA. "rsa"
and "ec" are the only valid values.`,
			},

			"key_bits": &framework.FieldSchema{
				Type:    framework.TypeInt,
				Default: 2048,
				Description: `The number of bits to use. You will almost
certainly want to change this if you adjust
the key_type.`,
			},

			"key_usage": &framework.FieldSchema{
				Type:    framework.TypeString,
				Default: "DigitalSignature,KeyAgreement,KeyEncipherment",
				Description: `A comma-separated set of key usages (not extended
key usages). Valid values can be found at
https://golang.org/pkg/crypto/x509/#KeyUsage
-- simply drop the "KeyUsage" part of the name.
To remove all key usages from being set, set
this value to an empty string.`,
			},

			"use_csr_common_name": &framework.FieldSchema{
				Type:    framework.TypeBool,
				Default: true,
				Description: `If set, when used with a signing profile,
the common name in the CSR will be used. This
does *not* include any requested Subject Alternative
Names. Defaults to true.`,
			},
		},

		Callbacks: map[logical.Operation]framework.OperationFunc{
			logical.ReadOperation:   b.pathRoleRead,
			logical.UpdateOperation: b.pathRoleCreate,
			logical.DeleteOperation: b.pathRoleDelete,
		},

		HelpSynopsis:    pathRoleHelpSyn,
		HelpDescription: pathRoleHelpDesc,
	}
}

func (b *backend) getRole(s logical.Storage, n string) (*roleEntry, error) {
	entry, err := s.Get("role/" + n)
	if err != nil {
		return nil, err
	}
	if entry == nil {
		return nil, nil
	}

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

	// Migrate existing saved entries and save back if changed
	modified := false
	if len(result.TTL) == 0 && len(result.Lease) != 0 {
		result.TTL = result.Lease
		result.Lease = ""
		modified = true
	}
	if len(result.MaxTTL) == 0 && len(result.LeaseMax) != 0 {
		result.MaxTTL = result.LeaseMax
		result.LeaseMax = ""
		modified = true
	}
	if result.AllowBaseDomain {
		result.AllowBaseDomain = false
		result.AllowBareDomains = true
		modified = true
	}
	if result.AllowedBaseDomain != "" {
		found := false
		allowedDomains := strings.Split(result.AllowedDomains, ",")
		if len(allowedDomains) != 0 {
			for _, v := range allowedDomains {
				if v == result.AllowedBaseDomain {
					found = true
					break
				}
			}
		}
		if !found {
			if result.AllowedDomains == "" {
				result.AllowedDomains = result.AllowedBaseDomain
			} else {
				result.AllowedDomains += "," + result.AllowedBaseDomain
			}
		}
		result.AllowedBaseDomain = ""
		modified = true
	}

	if modified {
		jsonEntry, err := logical.StorageEntryJSON("role/"+n, &result)
		if err != nil {
			return nil, err
		}
		if err := s.Put(jsonEntry); err != nil {
			return nil, err
		}
	}

	return &result, nil
}

func (b *backend) pathRoleDelete(
	req *logical.Request, data *framework.FieldData) (*logical.Response, error) {
	err := req.Storage.Delete("role/" + data.Get("name").(string))
	if err != nil {
		return nil, err
	}

	return nil, nil
}

func (b *backend) pathRoleRead(
	req *logical.Request, data *framework.FieldData) (*logical.Response, error) {
	role, err := b.getRole(req.Storage, data.Get("name").(string))
	if err != nil {
		return nil, err
	}
	if role == nil {
		return nil, nil
	}

	hasMax := true
	if len(role.MaxTTL) == 0 {
		role.MaxTTL = "(system default)"
		hasMax = false
	}
	if len(role.TTL) == 0 {
		if hasMax {
			role.TTL = "(system default, capped to role max)"
		} else {
			role.TTL = "(system default)"
		}
	}

	resp := &logical.Response{
		Data: structs.New(role).Map(),
	}

	if resp.Data == nil {
		return nil, fmt.Errorf("error converting role data to response")
	}

	// These values are deprecated and the entries are migrated on read
	delete(resp.Data, "lease")
	delete(resp.Data, "lease_max")
	delete(resp.Data, "allowed_base_domain")

	return resp, nil
}

func (b *backend) pathRoleList(
	req *logical.Request, d *framework.FieldData) (*logical.Response, error) {
	entries, err := req.Storage.List("role/")
	if err != nil {
		return nil, err
	}

	return logical.ListResponse(entries), nil
}

func (b *backend) pathRoleCreate(
	req *logical.Request, data *framework.FieldData) (*logical.Response, error) {
	var err error
	name := data.Get("name").(string)

	entry := &roleEntry{
		MaxTTL:              data.Get("max_ttl").(string),
		TTL:                 data.Get("ttl").(string),
		AllowLocalhost:      data.Get("allow_localhost").(bool),
		AllowedDomains:      data.Get("allowed_domains").(string),
		AllowBareDomains:    data.Get("allow_bare_domains").(bool),
		AllowSubdomains:     data.Get("allow_subdomains").(bool),
		AllowAnyName:        data.Get("allow_any_name").(bool),
		EnforceHostnames:    data.Get("enforce_hostnames").(bool),
		AllowIPSANs:         data.Get("allow_ip_sans").(bool),
		ServerFlag:          data.Get("server_flag").(bool),
		ClientFlag:          data.Get("client_flag").(bool),
		CodeSigningFlag:     data.Get("code_signing_flag").(bool),
		EmailProtectionFlag: data.Get("email_protection_flag").(bool),
		KeyType:             data.Get("key_type").(string),
		KeyBits:             data.Get("key_bits").(int),
		UseCSRCommonName:    data.Get("use_csr_common_name").(bool),
		KeyUsage:            data.Get("key_usage").(string),
	}

	if entry.KeyType == "rsa" && entry.KeyBits < 2048 {
		return logical.ErrorResponse("RSA keys < 2048 bits are unsafe and not supported"), nil
	}

	var maxTTL time.Duration
	maxSystemTTL := b.System().MaxLeaseTTL()
	if len(entry.MaxTTL) == 0 {
		maxTTL = maxSystemTTL
	} else {
		maxTTL, err = time.ParseDuration(entry.MaxTTL)
		if err != nil {
			return logical.ErrorResponse(fmt.Sprintf(
				"Invalid ttl: %s", err)), nil
		}
	}
	if maxTTL > maxSystemTTL {
		return logical.ErrorResponse("Requested max TTL is higher than backend maximum"), nil
	}

	ttl := b.System().DefaultLeaseTTL()
	if len(entry.TTL) != 0 {
		ttl, err = time.ParseDuration(entry.TTL)
		if err != nil {
			return logical.ErrorResponse(fmt.Sprintf(
				"Invalid ttl: %s", err)), nil
		}
	}
	if ttl > maxTTL {
		// If they are using the system default, cap it to the role max;
		// if it was specified on the command line, make it an error
		if len(entry.TTL) == 0 {
			ttl = maxTTL
		} else {
			return logical.ErrorResponse(
				`"ttl" value must be less than "max_ttl" and/or backend default max lease TTL value`,
			), nil
		}
	}

	// Persist clamped TTLs
	entry.TTL = ttl.String()
	entry.MaxTTL = maxTTL.String()

	if errResp := validateKeyTypeLength(entry.KeyType, entry.KeyBits); errResp != nil {
		return errResp, nil
	}

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

	return nil, nil
}

func parseKeyUsages(input string) int {
	var parsedKeyUsages x509.KeyUsage
	splitKeyUsage := strings.Split(input, ",")
	for _, k := range splitKeyUsage {
		switch strings.ToLower(strings.TrimSpace(k)) {
		case "digitalsignature":
			parsedKeyUsages |= x509.KeyUsageDigitalSignature
		case "contentcommitment":
			parsedKeyUsages |= x509.KeyUsageContentCommitment
		case "keyencipherment":
			parsedKeyUsages |= x509.KeyUsageKeyEncipherment
		case "dataencipherment":
			parsedKeyUsages |= x509.KeyUsageDataEncipherment
		case "keyagreement":
			parsedKeyUsages |= x509.KeyUsageKeyAgreement
		case "certsign":
			parsedKeyUsages |= x509.KeyUsageCertSign
		case "crlsign":
			parsedKeyUsages |= x509.KeyUsageCRLSign
		case "encipheronly":
			parsedKeyUsages |= x509.KeyUsageEncipherOnly
		case "decipheronly":
			parsedKeyUsages |= x509.KeyUsageDecipherOnly
		}
	}

	return int(parsedKeyUsages)
}

type roleEntry struct {
	LeaseMax              string `json:"lease_max" structs:"lease_max" mapstructure:"lease_max"`
	Lease                 string `json:"lease" structs:"lease" mapstructure:"lease"`
	MaxTTL                string `json:"max_ttl" structs:"max_ttl" mapstructure:"max_ttl"`
	TTL                   string `json:"ttl" structs:"ttl" mapstructure:"ttl"`
	AllowLocalhost        bool   `json:"allow_localhost" structs:"allow_localhost" mapstructure:"allow_localhost"`
	AllowedBaseDomain     string `json:"allowed_base_domain" structs:"allowed_base_domain" mapstructure:"allowed_base_domain"`
	AllowedDomains        string `json:"allowed_domains" structs:"allowed_domains" mapstructure:"allowed_domains"`
	AllowBaseDomain       bool   `json:"allow_base_domain" structs:"allow_base_domain" mapstructure:"allow_base_domain"`
	AllowBareDomains      bool   `json:"allow_bare_domains" structs:"allow_bare_domains" mapstructure:"allow_bare_domains"`
	AllowTokenDisplayName bool   `json:"allow_token_displayname" structs:"allow_token_displayname" mapstructure:"allow_token_displayname"`
	AllowSubdomains       bool   `json:"allow_subdomains" structs:"allow_subdomains" mapstructure:"allow_subdomains"`
	AllowAnyName          bool   `json:"allow_any_name" structs:"allow_any_name" mapstructure:"allow_any_name"`
	EnforceHostnames      bool   `json:"enforce_hostnames" structs:"enforce_hostnames" mapstructure:"enforce_hostnames"`
	AllowIPSANs           bool   `json:"allow_ip_sans" structs:"allow_ip_sans" mapstructure:"allow_ip_sans"`
	ServerFlag            bool   `json:"server_flag" structs:"server_flag" mapstructure:"server_flag"`
	ClientFlag            bool   `json:"client_flag" structs:"client_flag" mapstructure:"client_flag"`
	CodeSigningFlag       bool   `json:"code_signing_flag" structs:"code_signing_flag" mapstructure:"code_signing_flag"`
	EmailProtectionFlag   bool   `json:"email_protection_flag" structs:"email_protection_flag" mapstructure:"email_protection_flag"`
	UseCSRCommonName      bool   `json:"use_csr_common_name" structs:"use_csr_common_name" mapstructure:"use_csr_common_name"`
	KeyType               string `json:"key_type" structs:"key_type" mapstructure:"key_type"`
	KeyBits               int    `json:"key_bits" structs:"key_bits" mapstructure:"key_bits"`
	MaxPathLength         *int   `json:",omitempty" structs:",omitempty"`
	KeyUsage              string `json:"key_usage" structs:"key_usage" mapstructure:"key_usage"`
}

const pathListRolesHelpSyn = `List the existing roles in this backend`

const pathListRolesHelpDesc = `Roles will be listed by the role name.`

const pathRoleHelpSyn = `Manage the roles that can be created with this backend.`

const pathRoleHelpDesc = `This path lets you manage the roles that can be created with this backend.`