package lobby

import (
	"context"
	"database/sql"
	"fmt"
	"gitea/price-is-wrong/pkg/lib/db"
	lobby "gitea/price-is-wrong/pkg/state/lobby/internal"
)

type Lobby struct {
	id      int
	Players []int
	Closed  bool
}

func Open(ctx context.Context, name string) (*Lobby, error) {
	if err := initialize(ctx); err != nil {
		return nil, fmt.Errorf("failed to initialize lobbies: %w", err)
	}

	if result, err := open(ctx, name); err != nil {
		return nil, err
	} else if result == nil {
		if err := create(ctx, name); err != nil {
			return nil, err
		}
	}

	return mustOpen(ctx, name)
}

func mustOpen(ctx context.Context, name string) (*Lobby, error) {
	result, err := open(ctx, name)
	if err != nil {
		return nil, err
	}
	if result == nil {
		return nil, fmt.Errorf("no lobby found with name %s", name)
	}
	return result, nil
}

func open(ctx context.Context, name string) (*Lobby, error) {
	row := db.From(ctx).QueryRow(`SELECT id FROM lobbies WHERE name=?`, name)
	if err := row.Err(); err != nil {
		return nil, fmt.Errorf("no lobby found with name %s", name)
	}

	var id sql.NullInt32
	if err := row.Scan(&id); err == sql.ErrNoRows || !id.Valid {
		return nil, nil
	} else if err != nil {
		return nil, fmt.Errorf("failed to scan id from lobby: %w", err)
	}

	return openID(ctx, int(id.Int32))
}

func openID(ctx context.Context, id int) (*Lobby, error) {
	rows, err := db.From(ctx).QueryContext(ctx, `
      SELECT payload
      FROM lobby_events
      WHERE lobby_events.lobby_id=?
      ORDER BY id
   `, id)
	if err != nil {
		return nil, fmt.Errorf("failed to query event payloads for id %d: %w", id, err)
	}
	defer rows.Close()

	result := Lobby{id: id}
	for rows.Next() {
		var b []byte
		if err := rows.Scan(&b); err != nil {
			return nil, fmt.Errorf("failed to scan event: %w", err)
		}
		event, err := lobby.ParseEvent(b)
		if err != nil {
			return nil, fmt.Errorf("failed to parse event: %w", err)
		}
		if err := result.apply(event); err != nil {
			return nil, fmt.Errorf("failed to apply event %s: %w", b, err)
		}
	}

	return &result, rows.Err()
}

func create(ctx context.Context, name string) error {
	_, err := db.From(ctx).ExecContext(ctx, `
      INSERT INTO lobbies (name) VALUES (?)
   `, name)
	return err
}

func initialize(ctx context.Context) error {
	_, err := db.From(ctx).ExecContext(ctx, `
      CREATE TABLE IF NOT EXISTS lobbies (
         id INTEGER PRIMARY KEY,
         name TEXT
      );
      CREATE TABLE IF NOT EXISTS lobby_events (
         id INTEGER PRIMARY KEY,
         lobby_id NUMBER,
         payload TEXT,
         FOREIGN KEY (lobby_id) REFERENCES lobbies (id)
      );
   `)
	return err
}