package volume

import (
	"fmt"
	"path/filepath"

	"github.com/alexei/docker-watcher/internal/store"
)

// ResolveParams holds the parameters needed to resolve a volume's host path.
type ResolveParams struct {
	BasePath    string
	ProjectName string
	StageName   string // required for instance and stage scopes
	ImageTag    string // required for instance scope
}

// ResolvePath returns the absolute host path for a volume based on its scope.
// Returns an error for ephemeral volumes (no host path) or missing parameters.
func ResolvePath(vol store.Volume, params ResolveParams) (string, error) {
	scope := vol.Scope
	if scope == "" {
		switch vol.Mode {
		case "isolated":
			scope = "instance"
		default:
			scope = "project"
		}
	}

	if scope == "ephemeral" {
		return "", fmt.Errorf("ephemeral volumes have no host path")
	}

	switch scope {
	case "instance":
		if params.StageName == "" || params.ImageTag == "" {
			return "", fmt.Errorf("instance scope requires stage and tag parameters")
		}
		return filepath.Join(params.BasePath, params.ProjectName, fmt.Sprintf("%s-%s", params.StageName, params.ImageTag), vol.Source), nil
	case "stage":
		if params.StageName == "" {
			return "", fmt.Errorf("stage scope requires stage parameter")
		}
		return filepath.Join(params.BasePath, params.ProjectName, params.StageName, vol.Source), nil
	case "project":
		return filepath.Join(params.BasePath, params.ProjectName, vol.Source), nil
	case "project_named":
		return filepath.Join(params.BasePath, params.ProjectName, "_named", vol.Name, vol.Source), nil
	case "named":
		return filepath.Join(params.BasePath, "_named", vol.Name, vol.Source), nil
	default:
		return filepath.Join(params.BasePath, params.ProjectName, vol.Source), nil
	}
}