package federation

import (
	"context"
	"encoding/json"
	"net/http"
)

// The end-to-end encryption half of the Server-Server API: asking another
// server for its users' device keys, claiming their one-time keys, and the
// EDUs that say a user's keys have changed.
//
// Keys travel as json.RawMessage. They are signed objects, and the only
// safe thing to do with a signed object on its way through is not to
// re-encode it.

// UserKeysQueryRequest is the body of POST /user/keys/query: user ID to the
// device IDs wanted, where an empty list asks for every device.
type UserKeysQueryRequest struct {
	DeviceKeys map[string][]string `json:"device_keys"`
}

// UserKeysQueryResponse is the answer to POST /user/keys/query.
type UserKeysQueryResponse struct {
	DeviceKeys      map[string]map[string]json.RawMessage `json:"device_keys"`
	MasterKeys      map[string]json.RawMessage            `json:"master_keys,omitempty"`
	SelfSigningKeys map[string]json.RawMessage            `json:"self_signing_keys,omitempty"`
}

// UserKeysClaimRequest is the body of POST /user/keys/claim: user ID, then
// device ID, then the algorithm of the key wanted.
type UserKeysClaimRequest struct {
	OneTimeKeys map[string]map[string]string `json:"one_time_keys"`
}

// UserKeysClaimResponse is the answer to POST /user/keys/claim: user ID,
// then device ID, then key ID, then the key.
type UserKeysClaimResponse struct {
	OneTimeKeys map[string]map[string]map[string]json.RawMessage `json:"one_time_keys"`
}

// UserDevicesResponse is the answer to GET /user/devices/{userId}: the
// whole of a user's device list, which a server asks for when the updates
// it was sent do not add up.
type UserDevicesResponse struct {
	UserID         string          `json:"user_id"`
	StreamID       int64           `json:"stream_id"`
	Devices        []UserDevice    `json:"devices"`
	MasterKey      json.RawMessage `json:"master_key,omitempty"`
	SelfSigningKey json.RawMessage `json:"self_signing_key,omitempty"`
}

// UserDevice is one device in a UserDevicesResponse.
type UserDevice struct {
	DeviceID          string          `json:"device_id"`
	Keys              json.RawMessage `json:"keys"`
	DeviceDisplayName string          `json:"device_display_name,omitempty"`
}

// DeviceListUpdateContent is the content of an m.device_list_update EDU:
// one device of one user changed, or went away.
type DeviceListUpdateContent struct {
	UserID            string          `json:"user_id"`
	DeviceID          string          `json:"device_id"`
	DeviceDisplayName string          `json:"device_display_name,omitempty"`
	StreamID          int64           `json:"stream_id"`
	PrevID            []int64         `json:"prev_id,omitempty"`
	Deleted           bool            `json:"deleted,omitempty"`
	Keys              json.RawMessage `json:"keys,omitempty"`
}

// SigningKeyUpdateContent is the content of an m.signing_key_update EDU: a
// user's cross-signing keys changed.
type SigningKeyUpdateContent struct {
	UserID         string          `json:"user_id"`
	MasterKey      json.RawMessage `json:"master_key,omitempty"`
	SelfSigningKey json.RawMessage `json:"self_signing_key,omitempty"`
}

// QueryUserKeys asks a server for its users' device and cross-signing
// keys.
func (c *Client) QueryUserKeys(ctx context.Context, destination string, req UserKeysQueryRequest) (UserKeysQueryResponse, error) {
	var out UserKeysQueryResponse
	err := c.do(ctx, request{
		method: http.MethodPost, destination: destination, signed: true,
		path: "/_matrix/federation/v1/user/keys/query", body: req,
	}, &out)
	return out, err
}

// ClaimUserKeys claims one-time keys of a server's users' devices.
func (c *Client) ClaimUserKeys(ctx context.Context, destination string, req UserKeysClaimRequest) (UserKeysClaimResponse, error) {
	var out UserKeysClaimResponse
	err := c.do(ctx, request{
		method: http.MethodPost, destination: destination, signed: true,
		path: "/_matrix/federation/v1/user/keys/claim", body: req,
	}, &out)
	return out, err
}

// UserDevices asks a server for one of its users' whole device list.
func (c *Client) UserDevices(ctx context.Context, destination, userID string) (UserDevicesResponse, error) {
	var out UserDevicesResponse
	err := c.do(ctx, request{
		method: http.MethodGet, destination: destination, signed: true,
		path: "/_matrix/federation/v1/user/devices/" + esc(userID),
	}, &out)
	return out, err
}