package datasource

import (
	"context"
	"fmt"
	"strings"

	"gitea.maximumdirect.net/ejr/weatherapi/internal/platform/config"
)

// DataSource is a generic opened datasource handle.
type DataSource interface {
	Close()
}

// Factory constructs datasource handles for a specific driver.
type Factory interface {
	Driver() string
	Open(ctx context.Context, cfg config.DatabaseConfig) (DataSource, error)
}

// Registry maps driver names to datasource factories.
type Registry struct {
	factories map[string]Factory
}

func NewRegistry() *Registry {
	return &Registry{factories: map[string]Factory{}}
}

func (r *Registry) Register(factory Factory) error {
	if factory == nil {
		return fmt.Errorf("register datasource factory: factory is nil")
	}
	driver := normalizeDriver(factory.Driver())
	if driver == "" {
		return fmt.Errorf("register datasource factory: factory driver is empty")
	}
	if _, exists := r.factories[driver]; exists {
		return fmt.Errorf("register datasource factory: driver %q already registered", driver)
	}
	r.factories[driver] = factory
	return nil
}

func (r *Registry) Open(ctx context.Context, cfg config.DatabaseConfig) (DataSource, error) {
	if r == nil {
		return nil, fmt.Errorf("open datasource: registry is nil")
	}
	driver := normalizeDriver(cfg.Driver)
	factory, ok := r.factories[driver]
	if !ok {
		return nil, fmt.Errorf("open datasource: unsupported driver %q", cfg.Driver)
	}
	ds, err := factory.Open(ctx, cfg)
	if err != nil {
		return nil, err
	}
	return ds, nil
}

func normalizeDriver(driver string) string {
	return strings.ToLower(strings.TrimSpace(driver))
}