// Package artifact owns shared build artifact identity rules.
package artifact

import (
	"fmt"
	"strings"
)

const ManifestFilename = "SHA256SUMS"

type Target struct {
	OS   string
	Arch string
}

// Settings contains normalized inputs shared by build execution and evidence.
type Settings struct {
	MainPackage string
	BinaryName  string
	Targets     []Target
}

type Declaration struct {
	Target   Target
	Filename string
}

// NormalizeSettings copies build inputs and removes duplicate targets while
// preserving their first occurrence.
func NormalizeSettings(mainPackage, binaryName string, targets []Target) Settings {
	return Settings{
		MainPackage: mainPackage,
		BinaryName:  binaryName,
		Targets:     NormalizeTargets(targets),
	}
}

// NormalizeTargets removes duplicate targets while preserving their first
// occurrence.
func NormalizeTargets(targets []Target) []Target {
	seen := make(map[Target]struct{}, len(targets))
	result := make([]Target, 0, len(targets))
	for _, target := range targets {
		if _, ok := seen[target]; ok {
			continue
		}
		seen[target] = struct{}{}
		result = append(result, target)
	}
	return result
}

// ValidComponent reports whether value is a nonempty filename component under
// the build and receipt contracts.
func ValidComponent(value string) bool {
	return value != "" && !strings.ContainsAny(value, "/\\\r\n")
}

// Filename returns the declared binary filename for one target.
func Filename(binaryName, version string, target Target) string {
	filename := fmt.Sprintf("%s-%s-%s-%s", binaryName, version, target.OS, target.Arch)
	if target.OS == "windows" {
		filename += ".exe"
	}
	return filename
}

// ExpectedBuild returns artifact declarations in target order. Callers retain
// responsibility for validating their boundary-specific build identity.
func ExpectedBuild(binaryName, version string, targets []Target) []Declaration {
	declarations := make([]Declaration, 0, len(targets))
	for _, target := range targets {
		declarations = append(declarations, Declaration{
			Target:   target,
			Filename: Filename(binaryName, version, target),
		})
	}
	return declarations
}