package main

// console_hostops.go — the person at the machine always wins: the console
// commands that take reach BACK. Every one
// of them only removes something — an approval, a grant, a hold — so none
// needs machine authority; the local switch (localdeny.go) draws the same line.

import (
	"errors"
	"fmt"
	"io"
	"os"
	"sort"
	"strconv"
	"strings"
	"time"
)

// cmdStepupDrop revokes one unused approval this box issued for a pairing.
// From the owner's account beside the machine's bastion it asks that
// bastion (owneracts.go): dropping only takes reach away, so no code.
func cmdStepupDrop(host string, machine bool, prefix string) error {
	return printOrAct(agentAskRequest{Act: "approvals-drop", Host: host, Machine: machine, ID: prefix},
		stepupCommand("approvals drop", host, machine, prefix),
		func() (string, error) { return stepupDropText(host, machine, prefix) })
}

func stepupDropText(host string, machine bool, prefix string) (string, error) {
	t, err := resolveStepupTarget(host, machine)
	if err != nil {
		return "", err
	}
	dir := t.dir
	prefix = strings.TrimSpace(prefix)
	if prefix == "" {
		return "", errors.New("which approval? (the id `approve` printed)")
	}
	stepupMu.Lock()
	defer stepupMu.Unlock()
	m := approvalsLoad(dir)
	var hits []string
	for id, a := range m {
		if !a.Used && strings.HasPrefix(id, prefix) {
			hits = append(hits, id)
		}
	}
	switch len(hits) {
	case 0:
		return "", fmt.Errorf("no unused approval starts with %q %s", prefix, t.forWhom())
	case 1:
	default:
		return "", fmt.Errorf("%d approvals start with %q — give more of the id", len(hits), prefix)
	}
	a := m[hits[0]]
	a.Used = true // burned without ever having run: the same end state a use reaches
	m[hits[0]] = a
	if err := approvalsSave(dir, m); err != nil {
		return "", err
	}
	return fmt.Sprintf("dropped approval %s (%s) — nothing can run on it now", hits[0][:8], a.Purpose), nil
}

// cmdGrantsDrop removes a held store grant from this box (through the
// owner's lane beside the machine's bastion, as cmdStepupDrop).
func cmdGrantsDrop(host, store string) error {
	return printOrAct(agentAskRequest{Act: "grants-drop", Host: host, ID: store},
		"grants drop "+store+hostFlagWords(host), func() (string, error) { return grantsDropText(host, store) })
}

func grantsDropText(host, store string) (string, error) {
	cfg, err := stepupPairing(host)
	if err != nil {
		return "", err
	}
	id, err := strconv.ParseInt(strings.TrimSpace(store), 10, 64)
	if err != nil {
		return "", errors.New("store id must be a number (the id on the host's store card)")
	}
	dir := cfg.dcnDir()
	present, err := dcnDropStore(dir, id, "dropped at this machine's console")
	if err != nil {
		return "", err
	}
	if !present {
		return fmt.Sprintf("store %d was not held here for %s", id, cfg.HostName), nil
	}
	return fmt.Sprintf("store %d dropped for %s — the host's reads of it stop now and it learns on the next check-in", id, cfg.HostName), nil
}

// cmdQuarantineClear lifts this box's hold on a pairing's write lanes.
func cmdQuarantineClear(host string) error {
	host = strings.TrimSpace(host)
	if host == "" {
		return errors.New("which host?")
	}
	if until := quarantinedUntil(host, time.Now()); until.IsZero() {
		fmt.Printf("%s is not quarantined here\n", host)
		return nil
	}
	quarantineClear(host)
	fmt.Printf("%s may ask this machine for writes again (with your approval, as before)\n", host)
	return nil
}

// cmdOpsList prints the ops and op grants a pairing holds here (ops.go).
// opRow is one op a Host holds here, verified against its signature or not.
type opRow struct {
	ID          string `json:"id"`
	Name        string `json:"name,omitempty"`
	Version     string `json:"version,omitempty"`
	Privilege   string `json:"privilege,omitempty"`
	Summary     string `json:"summary,omitempty"`
	NotVerified string `json:"not_verified,omitempty"`
}

// opGrantRow is one op grant this machine holds and has not dropped.
type opGrantRow struct {
	ID          string `json:"id"`
	Op          string `json:"op,omitempty"`
	Version     string `json:"version,omitempty"`
	RunsLeft    int    `json:"runs_left"`
	Until       string `json:"until,omitempty"`
	Within      string `json:"within,omitempty"`
	NotVerified string `json:"not_verified,omitempty"`
}

// opsRead is what ops and op grants one pairing holds on this machine.
type opsRead struct {
	Host               string       `json:"host"`
	Sandbox            bool         `json:"sandbox"`
	SandboxUnavailable string       `json:"sandbox_unavailable,omitempty"`
	Ops                []opRow      `json:"ops"`
	Grants             []opGrantRow `json:"grants"`
}

func readOps(o readOpts) (opsRead, error) {
	cfg, err := stepupPairing(o.Host)
	if err != nil {
		return opsRead{}, err
	}
	dir := cfg.dcnDir()
	v := opsRead{Host: cfg.HostName, Ops: []opRow{}, Grants: []opGrantRow{}}
	v.Sandbox, v.SandboxUnavailable = opSandboxAvailable()
	if entries, err := os.ReadDir(opsDir(dir)); err == nil {
		for _, e := range entries {
			if !e.IsDir() || e.Name() == opsRunsDirName || strings.HasSuffix(e.Name(), ".tmp") {
				continue
			}
			r := opRow{ID: e.Name()[:12]}
			if m, err := opLoad(dir, e.Name()); err == nil {
				r.Name, r.Version, r.Privilege, r.Summary = m.Name, m.Version, m.Privilege, m.Summary
			} else {
				r.NotVerified = err.Error()
			}
			v.Ops = append(v.Ops, r)
		}
	}
	f := opsLoad(dir)
	nonces := make([]string, 0, len(f.Grants))
	for nonce, rec := range f.Grants {
		if rec.Dropped == "" {
			nonces = append(nonces, nonce)
		}
	}
	sort.Strings(nonces)
	for _, nonce := range nonces {
		rec := f.Grants[nonce]
		r := opGrantRow{ID: nonce[:8], RunsLeft: rec.UsesLeft}
		if t, err := verifyOpTerms(dir, rec.TermsCanonical, rec.Signature, opKindGrant); err != nil {
			r.NotVerified = err.Error()
		} else {
			r.Op, r.Version, r.Until, r.Within = t.Op, t.Version, t.Expires, t.Bounds
		}
		v.Grants = append(v.Grants, r)
	}
	return v, nil
}

func cmdOpsList(host string, asJSON bool) error {
	v, err := readMachine("ops", readOpts{Host: host}, readOps)
	if err != nil {
		return laneRefusalError("ops", err)
	}
	if asJSON {
		return printJSON(os.Stdout, v)
	}
	printOps(os.Stdout, v)
	return nil
}

func printOps(w io.Writer, v opsRead) {
	if v.Sandbox {
		fmt.Fprintln(w, "sandbox: available")
	} else {
		fmt.Fprintln(w, "sandbox: NOT available —", v.SandboxUnavailable)
	}
	for _, r := range v.Ops {
		if r.NotVerified != "" {
			fmt.Fprintf(w, "op  [%s]  NOT VERIFIED: %s\n", r.ID, r.NotVerified)
			continue
		}
		fmt.Fprintf(w, "op  %s %s  as %s  [%s]\n    %s\n", r.Name, r.Version, r.Privilege, r.ID, r.Summary)
	}
	for _, r := range v.Grants {
		if r.NotVerified != "" {
			fmt.Fprintf(w, "grant [%s]  NOT VERIFIED: %s\n", r.ID, r.NotVerified)
			continue
		}
		fmt.Fprintf(w, "grant [%s]  %s %s  %d run(s) left, until %s\n    within: %s\n", r.ID, r.Op, r.Version, r.RunsLeft, r.Until, r.Within)
	}
	if len(v.Ops) == 0 && len(v.Grants) == 0 {
		fmt.Fprintln(w, "no ops held for", v.Host)
	}
}

// cmdOpsDrop takes a held op grant back at the console.
func cmdOpsDrop(host, prefix string) error {
	return printOrAct(agentAskRequest{Act: "ops-drop", Host: host, ID: prefix},
		"ops drop "+prefix+hostFlagWords(host), func() (string, error) { return opsDropText(host, prefix) })
}

func opsDropText(host, prefix string) (string, error) {
	cfg, err := stepupPairing(host)
	if err != nil {
		return "", err
	}
	dir := cfg.dcnDir()
	prefix = strings.TrimSpace(prefix)
	if prefix == "" {
		// Every nonce starts with "": with one grant held, an empty id
		// would drop it unnamed.
		return "", errors.New("which op grant? (the id `privatae-bastion ops` lists, or --all)")
	}
	if prefix == "--all" {
		dropped, err := opsDropWhere(dir, "dropped at this machine's console", func(string, *opGrantRec) bool { return true })
		if err != nil {
			return "", err
		}
		return fmt.Sprintf("%d op grant(s) dropped — the host cannot run under any of them again", len(dropped)), nil
	}
	var hits []string
	for nonce, rec := range opsLoad(dir).Grants {
		if rec.Dropped == "" && strings.HasPrefix(nonce, prefix) {
			hits = append(hits, nonce)
		}
	}
	switch len(hits) {
	case 0:
		return "", fmt.Errorf("no held op grant starts with %q", prefix)
	case 1:
	default:
		return "", fmt.Errorf("%d grants start with %q — give more of the id", len(hits), prefix)
	}
	if _, err := opsDropGrant(dir, hits[0], "dropped at this machine's console"); err != nil {
		return "", err
	}
	return fmt.Sprintf("op grant %s dropped — the host cannot run under it again", hits[0][:8]), nil
}

// printOrAct runs a narrowing act: through the owner's lane beside the
// machine's bastion (owneracts.go), else here, printing what it did either way.
func printOrAct(req agentAskRequest, adminCmd string, here func() (string, error)) error {
	var done string
	var err error
	if readsGoThroughLane() {
		done, err = actViaSock(req)
		if err != nil {
			return laneRefusalError(adminCmd, err)
		}
	} else if done, err = here(); err != nil {
		return err
	}
	fmt.Println(done)
	return nil
}

// hostFlagWords is " --host <host>" when one was named.
func hostFlagWords(host string) string {
	if host == "" {
		return ""
	}
	return " --host " + host
}