package delivery

import (
	"fmt"
	"os"
	"path/filepath"

	"go.maximumdirect.net/releasekit/internal/artifact"
	internalbuild "go.maximumdirect.net/releasekit/internal/build"
)

func declaredBuildAssets(result internalbuild.Result) ([]artifact.ExpectedAsset, error) {
	settings := result.Settings
	if len(settings.Targets) == 0 {
		if len(result.Artifacts) != 0 {
			return nil, fmt.Errorf("source-only build result contains artifacts")
		}
		return nil, nil
	}
	if len(result.Artifacts) != len(settings.Targets) {
		return nil, fmt.Errorf("build result must contain one artifact for each selected target")
	}
	declarations := artifact.ExpectedBuild(settings.BinaryName, result.Version, settings.Targets)
	wantByTarget := make(map[artifact.Target]string, len(declarations))
	for _, declaration := range declarations {
		target := declaration.Target
		if !artifact.ValidComponent(target.OS) || !artifact.ValidComponent(target.Arch) {
			return nil, fmt.Errorf("build result contains an invalid target")
		}
		if _, exists := wantByTarget[target]; exists {
			return nil, fmt.Errorf("build result repeats target %q", target.OS+"/"+target.Arch)
		}
		wantByTarget[target] = declaration.Filename
	}
	assets := make([]artifact.ExpectedAsset, 0, len(result.Artifacts)+1)
	seenTargets := make(map[artifact.Target]bool, len(result.Artifacts))
	for _, builtArtifact := range result.Artifacts {
		wantName, ok := wantByTarget[builtArtifact.Target]
		if !ok || seenTargets[builtArtifact.Target] || builtArtifact.Filename != wantName {
			return nil, fmt.Errorf("build artifact %q does not match a selected target and its declared name", builtArtifact.Filename)
		}
		seenTargets[builtArtifact.Target] = true
		if filepath.Base(builtArtifact.Path) != builtArtifact.Filename {
			return nil, fmt.Errorf("build artifact path %q does not end with filename %q", builtArtifact.Path, builtArtifact.Filename)
		}
		info, err := os.Stat(builtArtifact.Path)
		if err != nil {
			return nil, fmt.Errorf("inspect build artifact %q: %w", builtArtifact.Filename, err)
		}
		if !info.Mode().IsRegular() {
			return nil, fmt.Errorf("build artifact %q is not a regular file", builtArtifact.Filename)
		}
		assets = append(assets, artifact.ExpectedAsset{
			Filename: builtArtifact.Filename,
			SHA256:   builtArtifact.SHA256,
			Size:     info.Size(),
			Path:     builtArtifact.Path,
		})
	}
	manifest, err := artifact.BuildManifest(assets)
	if err != nil {
		return nil, fmt.Errorf("build checksum manifest: %w", err)
	}
	if manifest.Filename != "" {
		assets = append(assets, manifest)
	}
	return assets, nil
}