// spec.go - virtfs-based namespace specification for toolsrv.
package fs

import (
	"context"
	"fmt"
	"os"
	"strconv"
	"strings"

	"ollie/virtfs"
)

// Spec returns the virtfs specification for the toolsrv namespace.
// The server is captured by closures — no context threading needed.
func Spec(srv *Server) virtfs.FsNodeDecl {
	return virtfs.DirNode("/",
		virtfs.FileNode("ctl", 0222,
			virtfs.Doc("Control: write 'load <agentID> <tool>' or 'unload <agentID> <tool>'"),
			virtfs.Write(func(data []byte) error {
				return srv.Fs.HandleCtl(strings.TrimSpace(string(data)))
			}),
		),
		virtfs.FileNode("tools", 0666,
			virtfs.Doc("Tools: write agent ID, read tool list (rdwr)"),
			virtfs.Request(func(data []byte) ([]byte, error) {
				agentID := strings.TrimSpace(string(data))
				if agentID == "" {
					return nil, fmt.Errorf("agent ID required")
				}
				return []byte(srv.Fs.HandleToolsRequest(agentID)), nil
			}),
		),
		virtfs.FileNode("info", 0444,
			virtfs.Doc("Host info: platform, arch"),
			virtfs.Read(func() ([]byte, error) {
				return []byte(srv.HostInfo()), nil
			}),
		),
		virtfs.DirNode("proc",
			virtfs.FileNode("new", 0666,
				virtfs.Doc("Execute tool: write token + tool + args, read result (blocking)"),
				virtfs.Request(func(data []byte) ([]byte, error) {
					result, err := srv.Fs.HandleProcNew(context.Background(), string(data))
					if err != nil {
						return nil, err
					}
					return []byte(result), nil
				}),
			),
			virtfs.FileNode("new.bg", 0666,
				virtfs.Doc("Execute tool in background: write token + tool + args, read pid"),
				virtfs.Request(func(data []byte) ([]byte, error) {
					result, err := srv.Fs.HandleProcNewBg(context.Background(), string(data))
					if err != nil {
						return nil, err
					}
					return []byte(result), nil
				}),
			),
			virtfs.Each("{pid}", func() ([]virtfs.Binding, error) {
				pids := srv.Fs.ListProcs()
				var bindings []virtfs.Binding
				for _, pid := range pids {
					proc := srv.Fs.GetProc(pid)
					if proc == nil {
						continue
					}
					p := proc
					bindings = append(bindings, virtfs.Binding{
						Name: strconv.Itoa(pid),
						Children: []virtfs.FsNodeDecl{
							virtfs.FileNode("out", 0444,
								virtfs.Doc("Process output"),
								virtfs.Read(func() ([]byte, error) {
									return []byte(p.Output()), nil
								}),
							),
							virtfs.FileNode("wait", 0444,
								virtfs.Doc("Block until process exits, returns exit code"),
								virtfs.BlockOnce(func(_ context.Context, _ string) ([]byte, string, error) {
									exitCode := p.Wait()
									return []byte(fmt.Sprintf("%d\n", exitCode)), "", nil
								}),
							),
							virtfs.FileNode("stat", 0444,
								virtfs.Doc("Process status: running/exited, runtime, tool"),
								virtfs.Read(func() ([]byte, error) {
									return []byte(p.Stat()), nil
								}),
							),
							virtfs.FileNode("ctl", 0222,
								virtfs.Doc("Process control: write 'signal <N>' or 'dismiss'"),
								virtfs.Write(func(data []byte) error {
									return srv.Fs.HandleProcCtl(p.ID, strings.TrimSpace(string(data)))
								}),
							),
						},
					})
				}
				return bindings, nil
			}),
		),
	)
}

// Mode constants for convenience.
const (
	ModeReadOnly  os.FileMode = 0444
	ModeWriteOnly os.FileMode = 0222
	ModeReadWrite os.FileMode = 0666
)