package game

import (
	"context"
	"database/sql"

	"github.com/ryanhamamura/c4/db/repository"
)

// Persistence methods on GameStore (used during Get to hydrate from DB).

func (gs *GameStore) saveGame(g *Game) error {
	ctx := context.Background()

	_, err := gs.queries.GetGame(ctx, g.ID)
	if err == sql.ErrNoRows {
		_, err = gs.queries.CreateGame(ctx, repository.CreateGameParams{
			ID:          g.ID,
			Board:       g.BoardToJSON(),
			CurrentTurn: int64(g.CurrentTurn),
			Status:      int64(g.Status),
		})
		return err
	}
	if err != nil {
		return err
	}

	return gs.queries.UpdateGame(ctx, updateGameParams(g))
}

func (gs *GameStore) loadGame(id string) (*Game, error) {
	row, err := gs.queries.GetGame(context.Background(), id)
	if err != nil {
		return nil, err
	}
	return gameFromRow(row)
}

func (gs *GameStore) loadGamePlayers(id string) ([]*Player, error) {
	rows, err := gs.queries.GetGamePlayers(context.Background(), id)
	if err != nil {
		return nil, err
	}
	return playersFromRows(rows), nil
}

// Persistence methods on GameInstance (used during gameplay mutations).

func (gi *GameInstance) saveGame(g *Game) error {
	ctx := context.Background()

	_, err := gi.queries.GetGame(ctx, g.ID)
	if err == sql.ErrNoRows {
		_, err = gi.queries.CreateGame(ctx, repository.CreateGameParams{
			ID:          g.ID,
			Board:       g.BoardToJSON(),
			CurrentTurn: int64(g.CurrentTurn),
			Status:      int64(g.Status),
		})
		return err
	}
	if err != nil {
		return err
	}

	return gi.queries.UpdateGame(ctx, updateGameParams(g))
}

func (gi *GameInstance) saveGamePlayer(gameID string, player *Player, slot int) error {
	var userID, guestPlayerID sql.NullString
	if player.UserID != nil {
		userID = sql.NullString{String: *player.UserID, Valid: true}
	} else {
		guestPlayerID = sql.NullString{String: string(player.ID), Valid: true}
	}

	return gi.queries.CreateGamePlayer(context.Background(), repository.CreateGamePlayerParams{
		GameID:        gameID,
		UserID:        userID,
		GuestPlayerID: guestPlayerID,
		Nickname:      player.Nickname,
		Color:         int64(player.Color),
		Slot:          int64(slot),
	})
}

// Shared helpers for domain ↔ DB mapping.

func updateGameParams(g *Game) repository.UpdateGameParams {
	var winnerUserID sql.NullString
	if g.Winner != nil && g.Winner.UserID != nil {
		winnerUserID = sql.NullString{String: *g.Winner.UserID, Valid: true}
	}

	var winningCells sql.NullString
	if wc := g.WinningCellsToJSON(); wc != "" {
		winningCells = sql.NullString{String: wc, Valid: true}
	}

	var rematchGameID sql.NullString
	if g.RematchGameID != nil {
		rematchGameID = sql.NullString{String: *g.RematchGameID, Valid: true}
	}

	return repository.UpdateGameParams{
		Board:         g.BoardToJSON(),
		CurrentTurn:   int64(g.CurrentTurn),
		Status:        int64(g.Status),
		WinnerUserID:  winnerUserID,
		WinningCells:  winningCells,
		RematchGameID: rematchGameID,
		ID:            g.ID,
	}
}

func gameFromRow(row repository.Game) (*Game, error) {
	g := &Game{
		ID:          row.ID,
		CurrentTurn: int(row.CurrentTurn),
		Status:      GameStatus(row.Status),
	}

	if err := g.BoardFromJSON(row.Board); err != nil {
		return nil, err
	}

	if row.WinningCells.Valid {
		_ = g.WinningCellsFromJSON(row.WinningCells.String)
	}

	if row.RematchGameID.Valid {
		g.RematchGameID = &row.RematchGameID.String
	}

	return g, nil
}

func playersFromRows(rows []repository.GamePlayer) []*Player {
	players := make([]*Player, 0, len(rows))
	for _, row := range rows {
		player := &Player{
			Nickname: row.Nickname,
			Color:    int(row.Color),
		}

		if row.UserID.Valid {
			player.UserID = &row.UserID.String
			player.ID = PlayerID(row.UserID.String)
		} else if row.GuestPlayerID.Valid {
			player.ID = PlayerID(row.GuestPlayerID.String)
		}

		players = append(players, player)
	}
	return players
}