package pluginrequestmeta

import (
	"context"
	"errors"

	"github.com/grafana/grafana-plugin-sdk-go/backend"
)

// StatusSource is an enum-like string value representing the source of a
// plugin query data response status code
type StatusSource string

const (
	StatusSourcePlugin     StatusSource = "plugin"
	StatusSourceDownstream StatusSource = "downstream"
)

// DefaultStatusSource is the default StatusSource that should be used when it is not explicitly set by the plugin.
const DefaultStatusSource StatusSource = StatusSourcePlugin

type statusSourceCtxKey struct{}

// StatusSourceFromContext returns the plugin request status source stored in the context.
// If no plugin request status source is stored in the context, [DefaultStatusSource] is returned.
func StatusSourceFromContext(ctx context.Context) StatusSource {
	value, ok := ctx.Value(statusSourceCtxKey{}).(*StatusSource)
	if ok {
		return *value
	}
	return DefaultStatusSource
}

// WithStatusSource sets the plugin request status source for the context.
func WithStatusSource(ctx context.Context, s StatusSource) context.Context {
	return context.WithValue(ctx, statusSourceCtxKey{}, &s)
}

// WithDownstreamStatusSource mutates the provided context by setting the plugin request status source to
// StatusSourceDownstream. If the provided context does not have a plugin request status source, the context
// will not be mutated. This means that [WithStatusSource] has to be called before this function.
func WithDownstreamStatusSource(ctx context.Context) error {
	v, ok := ctx.Value(statusSourceCtxKey{}).(*StatusSource)
	if !ok {
		return errors.New("the provided context does not have a plugin request status source")
	}
	*v = StatusSourceDownstream
	return nil
}

// StatusSourceFromPluginErrorSource takes an error source returned by a plugin and returns the corresponding
// StatusSource. If the provided value is a zero-value (i.e.: the plugin did not set it), the function returns
// DefaultStatusSource.
func StatusSourceFromPluginErrorSource(pluginErrorSource backend.ErrorSource) StatusSource {
	if pluginErrorSource == "" {
		return DefaultStatusSource
	}
	return StatusSource(pluginErrorSource)
}