package osupdate

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"fmt"

	"gitea.dooplex.hu/admin/felhom-agent/internal/signedjobs"
)

// OpDockerStep is the signed op class of a Docker engine step (`11` §5.8): a ring-1 box takes an approved engine set,
// and every box takes an UNDO, only through it. CC may sign it until the first paying customer (R-530 ruling).
const OpDockerStep = "os_docker_step"

// DockerStepParams are the signed params. The wrapper compares Packages and Undo with the plan byte-for-byte.
type DockerStepParams struct {
	ReleaseID string    `json:"release_id"`
	Packages  []Package `json:"packages"`
	Undo      bool      `json:"undo"`
	VMID      int       `json:"vmid,omitempty"`
}

// DockerStepExecutor runs a verified os_docker_step (signedjobs.Executor). Guest finds the box's customer guest when
// the params name none; Gate (optional) takes the host-wide heavy-op gate so a step never runs beside a backup.
type DockerStepExecutor struct {
	Leg   *Leg
	Guest func(ctx context.Context) (int, error)
	Gate  func(ctx context.Context) (release func(), err error)
}

// Execute implements signedjobs.Executor.
func (e DockerStepExecutor) Execute(ctx context.Context, op string, params json.RawMessage) error {
	if op != OpDockerStep {
		return signedjobs.ErrNoExecutor
	}
	so, ok := signedjobs.SignedOpFrom(ctx)
	if !ok {
		return fmt.Errorf("os_docker_step: no signed envelope in the context — the wrapper could not verify it")
	}
	var p DockerStepParams
	if err := json.Unmarshal(params, &p); err != nil || len(p.Packages) == 0 {
		return fmt.Errorf("os_docker_step: params must name the engine set: %v", err)
	}
	vmid := p.VMID
	if vmid == 0 {
		if e.Guest == nil {
			return fmt.Errorf("os_docker_step: no vmid and no guest finder")
		}
		v, err := e.Guest(ctx)
		if err != nil {
			return fmt.Errorf("os_docker_step: find the customer guest: %w", err)
		}
		vmid = v
	}
	if e.Gate != nil {
		release, err := e.Gate(ctx)
		if err != nil {
			return fmt.Errorf("os_docker_step: heavy-op gate busy (a backup or restore-test runs): %w", err)
		}
		defer release()
	}
	rep := e.Leg.RunDockerSigned(ctx, vmid, p, so.Blob, string(so.Sig))
	switch rep.Outcome {
	case "applied", "nothing":
		if rep.Healthy {
			return nil
		}
	}
	return fmt.Errorf("os_docker_step: %s (%s) %s", rep.Outcome, rep.HealthReason, string(rep.Refused))
}

// RunDockerSigned is one signed Docker step (ring 1 or an undo): live-restore first (decision 87, a no-op when on),
// then the docker layer with the signed envelope, which the wrapper verifies itself.
func (l *Leg) RunDockerSigned(ctx context.Context, vmid int, p DockerStepParams, blob []byte, sig string) Report {
	unlock := l.lockPass(true)
	defer unlock()
	l.sendUnsentLocked(ctx) // R-868
	runID := l.now().UTC().Format("20060102T150405Z")
	lg := l.log().With("run", runID, "vmid", vmid, "trigger", "signed", "release", p.ReleaseID, "undo", p.Undo)
	if err := l.EnsureLiveRestore(ctx, runID, vmid); err != nil {
		return l.finish(ctx, lg, Report{RunID: runID, Layer: LayerDocker, Trigger: "signed", Ring: l.Block().Ring, VMID: vmid,
			Mode: "apply", ReleaseID: p.ReleaseID, Outcome: "failed", HealthReason: "live-restore could not be turned on: " + err.Error()})
	}
	rid := p.ReleaseID
	if rid == "" {
		rid = "signed-" + runID
	}
	return l.runLayer(ctx, runID, LayerDocker, vmid, "signed", l.Block(), dockerOpts{releaseID: rid, packages: p.Packages,
		undo: p.Undo, signed: map[string]string{"blob_b64": base64.StdEncoding.EncodeToString(blob), "sig": sig}})
}