package backendclient

import (
	"context"
	"net/http"
	"net/url"
)

// The Stage 8 response structs and client methods mirror the backend's social,
// account and history JSON DTOs. The transcode layer maps them to FlatBuffers.

// AccountRefResp is a referenced account with its display name resolved.
type AccountRefResp struct {
	AccountID   string `json:"account_id"`
	DisplayName string `json:"display_name"`
}

// FriendListResp is the caller's accepted friends.
type FriendListResp struct {
	Friends []AccountRefResp `json:"friends"`
}

// IncomingListResp is the friend requests awaiting the caller.
type IncomingListResp struct {
	Requests []AccountRefResp `json:"requests"`
}

// FriendCodeResp is a freshly issued one-time friend code.
type FriendCodeResp struct {
	Code          string `json:"code"`
	ExpiresAtUnix int64  `json:"expires_at_unix"`
}

// RedeemResultResp reports the friend gained by redeeming a code.
type RedeemResultResp struct {
	Friend AccountRefResp `json:"friend"`
}

// BlockListResp is the accounts the caller has blocked.
type BlockListResp struct {
	Blocked []AccountRefResp `json:"blocked"`
}

// StatsResp is a durable account's lifetime statistics.
type StatsResp struct {
	Wins          int `json:"wins"`
	Losses        int `json:"losses"`
	Draws         int `json:"draws"`
	MaxGamePoints int `json:"max_game_points"`
	MaxWordPoints int `json:"max_word_points"`
}

// InvitationInviteeResp is one invitee's seat and response with their name.
type InvitationInviteeResp struct {
	AccountID   string `json:"account_id"`
	DisplayName string `json:"display_name"`
	Seat        int    `json:"seat"`
	Response    string `json:"response"`
}

// InvitationResp is a friend-game invitation with its settings and invitees.
type InvitationResp struct {
	ID              string                  `json:"id"`
	Inviter         AccountRefResp          `json:"inviter"`
	Invitees        []InvitationInviteeResp `json:"invitees"`
	Variant         string                  `json:"variant"`
	TurnTimeoutSecs int                     `json:"turn_timeout_secs"`
	HintsAllowed    bool                    `json:"hints_allowed"`
	HintsPerPlayer  int                     `json:"hints_per_player"`
	DropoutTiles    string                  `json:"dropout_tiles"`
	Status          string                  `json:"status"`
	GameID          string                  `json:"game_id"`
	ExpiresAtUnix   int64                   `json:"expires_at_unix"`
}

// InvitationListResp is the caller's open invitations.
type InvitationListResp struct {
	Invitations []InvitationResp `json:"invitations"`
}

// GcgResp is a finished game's GCG export.
type GcgResp struct {
	GameID   string `json:"game_id"`
	Filename string `json:"filename"`
	Content  string `json:"content"`
}

// InvitationParams are the settings the inviter chooses for a friend game.
type InvitationParams struct {
	InviteeIDs      []string
	Variant         string
	TurnTimeoutSecs int
	HintsAllowed    bool
	HintsPerPlayer  int
	DropoutTiles    string
}

// --- friends ---

// SendFriendRequest sends a friend request to a played opponent.
func (c *Client) SendFriendRequest(ctx context.Context, userID, targetID string) error {
	return c.do(ctx, http.MethodPost, "/api/v1/user/friends/request", userID, "",
		map[string]string{"account_id": targetID}, nil)
}

// RespondFriendRequest accepts or declines an incoming request.
func (c *Client) RespondFriendRequest(ctx context.Context, userID, requesterID string, accept bool) error {
	return c.do(ctx, http.MethodPost, "/api/v1/user/friends/respond", userID, "",
		map[string]any{"requester_id": requesterID, "accept": accept}, nil)
}

// CancelFriendRequest withdraws the caller's own pending request.
func (c *Client) CancelFriendRequest(ctx context.Context, userID, targetID string) error {
	return c.do(ctx, http.MethodPost, "/api/v1/user/friends/cancel", userID, "",
		map[string]string{"account_id": targetID}, nil)
}

// Unfriend removes a friendship.
func (c *Client) Unfriend(ctx context.Context, userID, targetID string) error {
	return c.do(ctx, http.MethodDelete, "/api/v1/user/friends/"+url.PathEscape(targetID), userID, "", nil, nil)
}

// ListFriends returns the caller's accepted friends.
func (c *Client) ListFriends(ctx context.Context, userID string) (FriendListResp, error) {
	var out FriendListResp
	err := c.do(ctx, http.MethodGet, "/api/v1/user/friends", userID, "", nil, &out)
	return out, err
}

// ListIncoming returns the friend requests awaiting the caller.
func (c *Client) ListIncoming(ctx context.Context, userID string) (IncomingListResp, error) {
	var out IncomingListResp
	err := c.do(ctx, http.MethodGet, "/api/v1/user/friends/incoming", userID, "", nil, &out)
	return out, err
}

// IssueFriendCode issues a one-time friend code for the caller.
func (c *Client) IssueFriendCode(ctx context.Context, userID string) (FriendCodeResp, error) {
	var out FriendCodeResp
	err := c.do(ctx, http.MethodPost, "/api/v1/user/friends/code", userID, "", struct{}{}, &out)
	return out, err
}

// RedeemFriendCode redeems a friend code, befriending its issuer.
func (c *Client) RedeemFriendCode(ctx context.Context, userID, code string) (RedeemResultResp, error) {
	var out RedeemResultResp
	err := c.do(ctx, http.MethodPost, "/api/v1/user/friends/code/redeem", userID, "",
		map[string]string{"code": code}, &out)
	return out, err
}

// --- blocks ---

// Block blocks an account.
func (c *Client) Block(ctx context.Context, userID, targetID string) error {
	return c.do(ctx, http.MethodPost, "/api/v1/user/blocks", userID, "",
		map[string]string{"account_id": targetID}, nil)
}

// Unblock removes a block.
func (c *Client) Unblock(ctx context.Context, userID, targetID string) error {
	return c.do(ctx, http.MethodDelete, "/api/v1/user/blocks/"+url.PathEscape(targetID), userID, "", nil, nil)
}

// ListBlocks returns the accounts the caller has blocked.
func (c *Client) ListBlocks(ctx context.Context, userID string) (BlockListResp, error) {
	var out BlockListResp
	err := c.do(ctx, http.MethodGet, "/api/v1/user/blocks", userID, "", nil, &out)
	return out, err
}

// --- invitations ---

// CreateInvitation proposes a friend game to the named invitees.
func (c *Client) CreateInvitation(ctx context.Context, userID string, p InvitationParams) (InvitationResp, error) {
	var out InvitationResp
	body := map[string]any{
		"invitee_ids":       p.InviteeIDs,
		"variant":           p.Variant,
		"turn_timeout_secs": p.TurnTimeoutSecs,
		"hints_allowed":     p.HintsAllowed,
		"hints_per_player":  p.HintsPerPlayer,
		"dropout_tiles":     p.DropoutTiles,
	}
	err := c.do(ctx, http.MethodPost, "/api/v1/user/invitations", userID, "", body, &out)
	return out, err
}

// RespondInvitation accepts or declines an invitation by id.
func (c *Client) RespondInvitation(ctx context.Context, userID, invitationID string, accept bool) (InvitationResp, error) {
	var out InvitationResp
	action := "/decline"
	if accept {
		action = "/accept"
	}
	err := c.do(ctx, http.MethodPost, "/api/v1/user/invitations/"+url.PathEscape(invitationID)+action, userID, "", struct{}{}, &out)
	return out, err
}

// CancelInvitation withdraws the caller's own invitation.
func (c *Client) CancelInvitation(ctx context.Context, userID, invitationID string) error {
	return c.do(ctx, http.MethodDelete, "/api/v1/user/invitations/"+url.PathEscape(invitationID), userID, "", nil, nil)
}

// ListInvitations returns the caller's open invitations.
func (c *Client) ListInvitations(ctx context.Context, userID string) (InvitationListResp, error) {
	var out InvitationListResp
	err := c.do(ctx, http.MethodGet, "/api/v1/user/invitations", userID, "", nil, &out)
	return out, err
}

// --- profile, email, stats, gcg ---

// UpdateProfile overwrites the caller's editable profile and returns it.
func (c *Client) UpdateProfile(ctx context.Context, userID string, p ProfileResp) (ProfileResp, error) {
	var out ProfileResp
	body := map[string]any{
		"display_name":          p.DisplayName,
		"preferred_language":    p.PreferredLanguage,
		"time_zone":             p.TimeZone,
		"away_start":            p.AwayStart,
		"away_end":              p.AwayEnd,
		"block_chat":            p.BlockChat,
		"block_friend_requests": p.BlockFriendRequests,
	}
	err := c.do(ctx, http.MethodPut, "/api/v1/user/profile", userID, "", body, &out)
	return out, err
}

// EmailBindRequest asks the backend to mail a confirm-code binding email.
func (c *Client) EmailBindRequest(ctx context.Context, userID, email string) error {
	return c.do(ctx, http.MethodPost, "/api/v1/user/email/request", userID, "",
		map[string]string{"email": email}, nil)
}

// EmailBindConfirm verifies the code and binds the email, returning the profile.
func (c *Client) EmailBindConfirm(ctx context.Context, userID, email, code string) (ProfileResp, error) {
	var out ProfileResp
	err := c.do(ctx, http.MethodPost, "/api/v1/user/email/confirm", userID, "",
		map[string]string{"email": email, "code": code}, &out)
	return out, err
}

// Stats returns the caller's lifetime statistics.
func (c *Client) Stats(ctx context.Context, userID string) (StatsResp, error) {
	var out StatsResp
	err := c.do(ctx, http.MethodGet, "/api/v1/user/stats", userID, "", nil, &out)
	return out, err
}

// ExportGCG returns a finished game's GCG transcript.
func (c *Client) ExportGCG(ctx context.Context, userID, gameID string) (GcgResp, error) {
	var out GcgResp
	err := c.do(ctx, http.MethodGet, c.gamePath(gameID, "/gcg"), userID, "", nil, &out)
	return out, err
}