package trunk

import (
	"fmt"
	"strings"
)

// A mesh package is a Go module of a repository of the mesh's forge (ForgeModulePrefix): mesh-sdk's Go module, and an
// owner module's package (novox/hq ADR 0593 §1). The indexer alone reads which packages a module imports, their content
// digests and their latest published versions, and writes them in its state (PublishedPackages, ADR 0593 §2); a build
// writes the version it is asked into its own go.mod and go.sum (StepAsk.Packages).

// ForgeModulePrefix is the module path prefix of the Go modules the mesh's forge serves: a Go module whose path starts
// with it is a mesh package, git.novox.be/novox/<repository>[/<directory of the module in it>].
const ForgeModulePrefix = "git.novox.be/novox/"

// PackageRepository is the repository (<owner>/<name>) a mesh package is published from and the package's directory in
// it ("" for its root); false for a path that is not a forge module's.
func PackageRepository(pkg string) (repository, dir string, ok bool) {
	rest, found := strings.CutPrefix(pkg, ForgeModulePrefix)
	if !found || rest == "" {
		return "", "", false
	}
	name, dir, _ := strings.Cut(rest, "/")
	if name == "" {
		return "", "", false
	}
	return "novox/" + name, dir, true
}

// CheckImports refuses an import set (the imports of a module's kept inputs, of a build's answer and of a build log entry)
// that holds a path that is no mesh package's, or is not sorted and each once.
func CheckImports(imports []string) error {
	for i, pkg := range imports {
		if _, _, ok := PackageRepository(pkg); !ok || strings.ContainsAny(pkg, " \t\n@") {
			return fmt.Errorf("trunk: the import %q is no mesh package's path (it starts with %s)", pkg, ForgeModulePrefix)
		}
		if i > 0 && imports[i-1] >= pkg {
			return fmt.Errorf("trunk: the imports are not sorted and each once (%s after %s)", pkg, imports[i-1])
		}
	}
	return nil
}