package host

import (
	"context"
	"github.com/carlosframework/platform/internal/hostbox"
	"github.com/carlosframework/platform/internal/rootstate"
	"path/filepath"
)

// Rebase only the journal's deny-only descriptor set. The retained inventory
// proves which filesystem its old device number named; the old file inode is
// never an ownership grant. Unmapped or ambiguous filesystems refuse recovery.
func (k LinuxStopKernel) rebootStopFiles(ctx context.Context, in StopInventory, files []hostbox.StopFileIdentity) ([]hostbox.StopFileIdentity, error) {
	type filesystem struct {
		id     string
		device uint64
	}
	devices := map[uint64]filesystem{}
	for _, e := range in.Entries {
		if e.Kind != "path" || e.Materialization != "materialized" {
			continue
		}
		if err := ctx.Err(); err != nil {
			return nil, err
		}
		root := k.ManagedRoots[e.ManagedRoot]
		if !filepath.IsAbs(root) || !filepath.IsLocal(e.RelativePath) {
			return nil, ErrClaimStopInventory
		}
		f, err := hostbox.OpenInventoryFile(filepath.Join(root, e.RelativePath))
		if err != nil {
			return nil, err
		}
		err = hostbox.VerifyInventoryFile(f, e)
		if err == nil {
			err = hostbox.VerifyInventoryIdentity(root, e)
		}
		now, captureErr := rootstate.ObjectIdentity(f)
		f.Close()
		if err != nil {
			return nil, err
		}
		if captureErr != nil {
			return nil, captureErr
		}
		next := filesystem{e.Identity.Filesystem, now.Device}
		if prior, ok := devices[e.Device]; ok && prior != next {
			return nil, ErrClaimStopInventory
		}
		devices[e.Device] = next
	}
	out := make([]hostbox.StopFileIdentity, 0, len(files))
	for _, f := range files {
		current, ok := devices[f.Device]
		if !ok || f.Inode == 0 {
			return nil, ErrClaimStopInventory
		}
		out = append(out, hostbox.StopFileIdentity{Device: current.device, Inode: f.Inode})
	}
	return out, nil
}