package mongodb

import (
	"encoding/json"

	"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:    pathRoleHelpSyn,
		HelpDescription: pathRoleHelpDesc,
	}
}

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.",
			},
			"db": &framework.FieldSchema{
				Type:        framework.TypeString,
				Default:     "admin",
				Description: "Name of the database users should be created in for this role.",
			},
			"roles": &framework.FieldSchema{
				Type:        framework.TypeString,
				Description: "MongoDB roles to assign to the users generated for this role.",
			},
		},

		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) Role(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
	}

	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.Role(req.Storage, data.Get("name").(string))
	if err != nil {
		return nil, err
	}
	if role == nil {
		return nil, nil
	}

	rolesJsonBytes, err := json.Marshal(role.MongoDBRoles)
	if err != nil {
		return nil, err
	}

	return &logical.Response{
		Data: map[string]interface{}{
			"db": role.DB,
			"roles": string(rolesJsonBytes),
		},
	}, 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) {
	name := data.Get("name").(string)
	roleDB := data.Get("db").(string)

	// Example roles JSON: [ "readWrite", { "role": "readWrite", "db": "test" } ]
	var roles []interface{}
	rolesJson := []byte(data.Get("roles").(string))
	if len(rolesJson) > 0 {
		var rolesArray []interface{}
		err := json.Unmarshal(rolesJson, &rolesArray)
		if err != nil {
			return nil, err
		}
		for _, rawItem := range rolesArray {
			switch item := rawItem.(type) {
			case string:
				roles = append(roles, item)
			case map[string]interface{}:
				if db, ok := item["db"].(string); ok {
					if r, ok := item["role"].(string); ok {
						roles = append(roles, mongodbRole{Role: r, DB: db})
					}
				}
			}
		}
	}

	// Store it
	entry, err := logical.StorageEntryJSON("role/"+name, &roleEntry{
		DB:    roleDB,
		MongoDBRoles: roles,
	})
	if err != nil {
		return nil, err
	}
	if err := req.Storage.Put(entry); err != nil {
		return nil, err
	}

	return nil, nil
}

type roleEntry struct {
	DB           string        `json:"db"`
	MongoDBRoles []interface{} `json:"roles"`
}

type mongodbRole struct {
	Role string `json:"role" bson:"role"`
	DB   string `json:"db"   bson:"db"`
}

const pathRoleHelpSyn = `
Manage the roles used to generate MongoDB credentials.
`

const pathRoleHelpDesc = `
This path lets you manage the roles used to generate MongoDB credentials.

The "db" parameter specifies which database users should be created in
for a given role.

The "roles" parameter specifies the MongoDB roles that should be assigned
to users created for a given role. Just like when creating a user directly
using db.createUser, the roles JSON array can specify both built-in roles
and user-defined roles for both the database the user is created in and
for other databases. Please consult the MongoDB documentation for more
details on Role-Based Access Control in MongoDB.
`