package db

import (
	"context"
	"database/sql"

	"github.com/ryanhamamura/c4/db/gen"
	"github.com/ryanhamamura/c4/game"
	"github.com/ryanhamamura/c4/snake"
)

type GamePersister struct {
	queries *gen.Queries
}

func NewGamePersister(q *gen.Queries) *GamePersister {
	return &GamePersister{queries: q}
}

func (p *GamePersister) SaveGame(g *game.Game) error {
	ctx := context.Background()

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

	var winnerUserID sql.NullString
	if g.Winner != nil && g.Winner.UserID != nil {
		winnerUserID = sql.NullString{String: *g.Winner.UserID, Valid: true}
	}

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

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

	return p.queries.UpdateGame(ctx, gen.UpdateGameParams{
		Board:         g.BoardToJSON(),
		CurrentTurn:   int64(g.CurrentTurn),
		Status:        int64(g.Status),
		WinnerUserID:  winnerUserID,
		WinningCells:  winningCells,
		RematchGameID: rematchGameID,
		ID:            g.ID,
	})
}

func (p *GamePersister) LoadGame(id string) (*game.Game, error) {
	ctx := context.Background()
	row, err := p.queries.GetGame(ctx, id)
	if err != nil {
		return nil, err
	}

	g := &game.Game{
		ID:          row.ID,
		CurrentTurn: int(row.CurrentTurn),
		Status:      game.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 (p *GamePersister) SaveGamePlayer(gameID string, player *game.Player, slot int) error {
	ctx := context.Background()

	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 p.queries.CreateGamePlayer(ctx, gen.CreateGamePlayerParams{
		GameID:        gameID,
		UserID:        userID,
		GuestPlayerID: guestPlayerID,
		Nickname:      player.Nickname,
		Color:         int64(player.Color),
		Slot:          int64(slot),
	})
}

func (p *GamePersister) LoadGamePlayers(gameID string) ([]*game.Player, error) {
	ctx := context.Background()
	rows, err := p.queries.GetGamePlayers(ctx, gameID)
	if err != nil {
		return nil, err
	}

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

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

		players = append(players, player)
	}

	return players, nil
}

func (p *GamePersister) DeleteGame(id string) error {
	ctx := context.Background()
	return p.queries.DeleteGame(ctx, id)
}

// SnakePersister implements snake.Persister
type SnakePersister struct {
	queries *gen.Queries
}

func NewSnakePersister(q *gen.Queries) *SnakePersister {
	return &SnakePersister{queries: q}
}

func (p *SnakePersister) SaveSnakeGame(sg *snake.SnakeGame) error {
	ctx := context.Background()

	boardJSON := "{}"
	if sg.State != nil {
		boardJSON = sg.State.ToJSON()
	}

	var gridWidth, gridHeight sql.NullInt64
	if sg.State != nil {
		gridWidth = sql.NullInt64{Int64: int64(sg.State.Width), Valid: true}
		gridHeight = sql.NullInt64{Int64: int64(sg.State.Height), Valid: true}
	}

	_, err := p.queries.GetSnakeGame(ctx, sg.ID)
	if err == sql.ErrNoRows {
		_, err = p.queries.CreateSnakeGame(ctx, gen.CreateSnakeGameParams{
			ID:         sg.ID,
			Board:      boardJSON,
			Status:     int64(sg.Status),
			GridWidth:  gridWidth,
			GridHeight: gridHeight,
		})
		return err
	}
	if err != nil {
		return err
	}

	var winnerUserID sql.NullString
	if sg.Winner != nil && sg.Winner.UserID != nil {
		winnerUserID = sql.NullString{String: *sg.Winner.UserID, Valid: true}
	}

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

	return p.queries.UpdateSnakeGame(ctx, gen.UpdateSnakeGameParams{
		Board:         boardJSON,
		Status:        int64(sg.Status),
		WinnerUserID:  winnerUserID,
		RematchGameID: rematchGameID,
		ID:            sg.ID,
	})
}

func (p *SnakePersister) LoadSnakeGame(id string) (*snake.SnakeGame, error) {
	ctx := context.Background()
	row, err := p.queries.GetSnakeGame(ctx, id)
	if err != nil {
		return nil, err
	}

	state, err := snake.GameStateFromJSON(row.Board)
	if err != nil {
		state = &snake.GameState{}
	}
	if row.GridWidth.Valid {
		state.Width = int(row.GridWidth.Int64)
	}
	if row.GridHeight.Valid {
		state.Height = int(row.GridHeight.Int64)
	}

	sg := &snake.SnakeGame{
		ID:      row.ID,
		State:   state,
		Players: make([]*snake.Player, 8),
		Status:  snake.Status(row.Status),
	}

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

	return sg, nil
}

func (p *SnakePersister) SaveSnakePlayer(gameID string, player *snake.Player) error {
	ctx := context.Background()

	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 p.queries.CreateSnakePlayer(ctx, gen.CreateSnakePlayerParams{
		GameID:        gameID,
		UserID:        userID,
		GuestPlayerID: guestPlayerID,
		Nickname:      player.Nickname,
		Color:         int64(player.Slot + 1),
		Slot:          int64(player.Slot),
	})
}

func (p *SnakePersister) LoadSnakePlayers(gameID string) ([]*snake.Player, error) {
	ctx := context.Background()
	rows, err := p.queries.GetSnakePlayers(ctx, gameID)
	if err != nil {
		return nil, err
	}

	players := make([]*snake.Player, 0, len(rows))
	for _, row := range rows {
		player := &snake.Player{
			Nickname: row.Nickname,
			Slot:     int(row.Slot),
		}

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

		players = append(players, player)
	}

	return players, nil
}

func (p *SnakePersister) DeleteSnakeGame(id string) error {
	ctx := context.Background()
	return p.queries.DeleteSnakeGame(ctx, id)
}