package api

import (
	"context"
	"crypto/sha256"
	"crypto/subtle"
	"encoding/hex"
	"encoding/json"
	"errors"
	"fmt"
	"log"
	"net"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"
	"time"

	"github.com/go-chi/chi/v5"

	"vetting/internal/events"
	"vetting/internal/hold"
	"vetting/internal/logs"
	"vetting/internal/model"
	"vetting/internal/notify"
	"vetting/internal/orchestrator"
	"vetting/internal/pxe"
	"vetting/internal/report"
	"vetting/internal/spec"
	"vetting/internal/store"
)

// Agent collects the collaborators used by agent-facing HTTP routes:
// the iPXE chainload endpoint and the /api/v1/runs/:id/* endpoints.
type Agent struct {
	Hosts           *store.Hosts
	Runs            *store.Runs
	Stages          *store.Stages
	Artifacts       *store.Artifacts
	SpecDiffs       *store.SpecDiffs
	Measurements    *store.Measurements
	Runner          *orchestrator.Runner
	EventHub        *events.Hub
	Logs            *logs.Hub
	Notify          *notify.Registry
	ArtifactsDir    string // ./var/artifacts
	OrchestratorURL string // baked into iPXE cmdline
	PublicURL       string // user-visible URL base for notification click-throughs
	LiveKernelURL   string
	LiveInitrdURL   string
	TLSCertFPR      string // optional; empty = skip pinning
	IperfPort       int    // orchestrator-supervised iperf3 port; 0 = 5201
}

// IPXEScript serves a per-MAC iPXE script. Called by iPXE itself after
// dnsmasq hands it the chainload URL. Unknown MAC → halt script.
// Known MAC with no active run → poweroff script. Known MAC with active
// run → real boot script; the fetch triggers PXEObserved.
func (a *Agent) IPXEScript(w http.ResponseWriter, r *http.Request) {
	mac := strings.ToLower(strings.TrimSpace(chi.URLParam(r, "mac")))
	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
	w.Header().Set("Cache-Control", "no-store")

	if !macRe.MatchString(mac) {
		log.Printf("ipxe: rejected malformed mac %q from %s", mac, r.RemoteAddr)
		_, _ = w.Write([]byte(pxe.NotRegisteredScript(mac)))
		return
	}

	run, err := a.Runs.FindActiveByMAC(r.Context(), mac)
	if err != nil {
		log.Printf("ipxe: find run by mac %s: %v", mac, err)
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}
	if run == nil {
		_, _ = w.Write([]byte(pxe.NoActiveRunScript(mac)))
		return
	}

	// The token hash in the DB is the sha256 of the plaintext. The
	// plaintext itself cannot be recovered from the hash — we issued it
	// once when the run was created. For iPXE we re-issue a fresh token
	// on every PXE fetch: this is safe because the hash in the DB is
	// rewritten to match and only the most recent PXE can be claimed.
	plain, hash, err := orchestrator.IssueRunToken()
	if err != nil {
		http.Error(w, "token", http.StatusInternalServerError)
		return
	}
	if err := a.Runs.RotateTokenHash(r.Context(), run.ID, hash); err != nil {
		log.Printf("ipxe: rotate token run %d: %v", run.ID, err)
		http.Error(w, "token", http.StatusInternalServerError)
		return
	}

	script := pxe.BuildScript(pxe.IPXEParams{
		OrchestratorURL: a.OrchestratorURL,
		LiveKernelURL:   a.LiveKernelURL,
		LiveInitrdURL:   a.LiveInitrdURL,
		TLSCertFPR:      a.TLSCertFPR,
		RunID:           run.ID,
		MAC:             mac,
		Token:           plain,
	})
	_, _ = w.Write([]byte(script))

	// iPXE has now fetched the script — treat this as PXEObserved. If we
	// were already in Booting the transition table allows staying.
	if _, err := a.Runner.Transition(r.Context(), run.ID, orchestrator.TriggerPXEObserved); err != nil {
		// Non-fatal: the agent may still claim via /claim.
		log.Printf("ipxe: PXEObserved for run %d: %v", run.ID, err)
	}
}

// Hello is the first call an agent makes once userspace is up. It's
// idempotent and only writes a log line; the authoritative transition
// comes from /claim. The agent sends Hello early so operators see a
// signal in the tile even before the token is validated.
func (a *Agent) Hello(w http.ResponseWriter, r *http.Request) {
	runID, ok := runIDFromURL(w, r)
	if !ok {
		return
	}
	if _, ok := a.authenticate(w, r, runID); !ok {
		return
	}
	log.Printf("agent hello: run=%d remote=%s", runID, r.RemoteAddr)
	writeJSON(w, http.StatusOK, map[string]any{"ok": true, "run_id": runID})
}

// Claim is the binding call: the agent proves it holds the plaintext
// token for this run, and in return the orchestrator transitions to
// InventoryCheck and seeds the stage rows. All destructive actions the
// agent takes later require a prior successful claim.
func (a *Agent) Claim(w http.ResponseWriter, r *http.Request) {
	runID, ok := runIDFromURL(w, r)
	if !ok {
		return
	}
	run, ok := a.authenticate(w, r, runID)
	if !ok {
		return
	}

	var body struct {
		AgentIP string `json:"agent_ip"`
	}
	if r.Body != nil {
		// agent_ip is informational; if missing fall back to RemoteAddr.
		_ = json.NewDecoder(r.Body).Decode(&body)
	}
	agentIP := strings.TrimSpace(body.AgentIP)
	if agentIP == "" {
		if host, _, err := net.SplitHostPort(r.RemoteAddr); err == nil {
			agentIP = host
		} else {
			agentIP = r.RemoteAddr
		}
	}

	// First claim seeds the stage rows; subsequent claims are a no-op
	// so agent retries after transient network failures stay safe.
	if len(mustListStages(a.Stages, r, runID)) == 0 {
		if err := a.Stages.Seed(r.Context(), runID); err != nil {
			log.Printf("claim: seed stages run %d: %v", runID, err)
			http.Error(w, "seed stages", http.StatusInternalServerError)
			return
		}
	}

	// Drive the transition. If we're already past Booting this returns
	// an error — treat as "already claimed" and report OK, don't 500.
	if run.State == model.StateWaitingWoL || run.State == model.StateBooting {
		if _, err := a.Runner.Transition(r.Context(), runID, orchestrator.TriggerAgentClaimed); err != nil {
			log.Printf("claim: transition run %d: %v", runID, err)
			http.Error(w, "transition", http.StatusConflict)
			return
		}
	}

	log.Printf("agent claimed: run=%d agent_ip=%s", runID, agentIP)

	// Stage-driven agent needs a bit of per-run config: the device
	// allowlist (serial + expected size) for Storage, and the iperf3
	// server port for Network. Parse the host's expected spec here so
	// the agent doesn't need to read YAML.
	expectedDisks := []map[string]any{}
	if host, err := a.Hosts.Get(r.Context(), run.HostID); err == nil && host != nil {
		if parsed, err := spec.Parse(host.ExpectedSpecYAML); err == nil && parsed != nil {
			for _, dd := range parsed.Disks {
				expectedDisks = append(expectedDisks, map[string]any{
					"serial":  dd.Serial,
					"size_gb": dd.SizeGB,
				})
			}
		}
	}
	iperfPort := a.IperfPort
	if iperfPort == 0 {
		iperfPort = 5201
	}
	writeJSON(w, http.StatusOK, map[string]any{
		"ok":             true,
		"run_id":         runID,
		"stages":         store.DefaultStageOrder,
		"expected_disks": expectedDisks,
		"iperf_port":     iperfPort,
	})
}

// Heartbeat is the agent's periodic liveness ping. The response body
// acts as a control channel: cmd=continue is the normal case; cmd=abort
// once the run enters FailedHolding/Released; cmd=retry_stage when the
// operator has overridden a failed stage (wipe-probe override).
func (a *Agent) Heartbeat(w http.ResponseWriter, r *http.Request) {
	runID, ok := runIDFromURL(w, r)
	if !ok {
		return
	}
	run, ok := a.authenticate(w, r, runID)
	if !ok {
		return
	}
	a.Runner.TouchHeartbeat(runID)

	cmd := "continue"
	resp := map[string]any{"state": run.State}
	switch {
	case run.State == model.StateCompleted:
		// Pipeline succeeded — agent should power the host down.
		cmd = "shutdown"
	case run.State == model.StateFailedHolding || run.State == model.StateReleased:
		cmd = "abort"
	case run.FailedStage == "Storage" && overrideWipeSet(run.OverrideFlagsJSON):
		// Operator pressed "Override wipe & retry". Agent should
		// re-enter Storage with the wipe-probe bypass armed.
		cmd = "retry_stage"
		resp["stage"] = "Storage"
		resp["override_flags"] = json.RawMessage(run.OverrideFlagsJSON)
	}
	resp["cmd"] = cmd
	writeJSON(w, http.StatusOK, resp)
}

// overrideWipeSet inspects a Run.OverrideFlagsJSON blob for the wipe flag.
// Malformed JSON is ignored — the operator has to reapply the override if
// it didn't round-trip correctly.
func overrideWipeSet(blob string) bool {
	if blob == "" {
		return false
	}
	var flags struct {
		Wipe bool `json:"wipe"`
	}
	_ = json.Unmarshal([]byte(blob), &flags)
	return flags.Wipe
}

// authenticate verifies the Bearer token against the run's stored hash
// and returns the Run for downstream handlers. Responds 401/404 on
// failure and returns ok=false so the caller can bail early.
func (a *Agent) authenticate(w http.ResponseWriter, r *http.Request, runID int64) (*model.Run, bool) {
	run, err := a.Runs.Get(r.Context(), runID)
	if err != nil {
		if errors.Is(err, store.ErrNotFound) {
			http.Error(w, "run not found", http.StatusNotFound)
			return nil, false
		}
		http.Error(w, "internal error", http.StatusInternalServerError)
		return nil, false
	}
	token := bearerToken(r)
	if token == "" {
		http.Error(w, "missing bearer", http.StatusUnauthorized)
		return nil, false
	}
	presented := orchestrator.HashRunToken(token)
	if subtle.ConstantTimeCompare([]byte(presented), []byte(run.AgentTokenHash)) != 1 {
		http.Error(w, "bad token", http.StatusUnauthorized)
		return nil, false
	}
	return run, true
}

func bearerToken(r *http.Request) string {
	h := r.Header.Get("Authorization")
	if !strings.HasPrefix(h, "Bearer ") {
		return ""
	}
	return strings.TrimSpace(strings.TrimPrefix(h, "Bearer "))
}

func runIDFromURL(w http.ResponseWriter, r *http.Request) (int64, bool) {
	idStr := chi.URLParam(r, "id")
	id, err := strconv.ParseInt(idStr, 10, 64)
	if err != nil || id <= 0 {
		http.Error(w, "bad run id", http.StatusBadRequest)
		return 0, false
	}
	return id, true
}

func writeJSON(w http.ResponseWriter, status int, body any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(body)
}

// mustListStages is a small wrapper that hides the error path from
// /claim — a DB read failure just pretends there are zero stages, and
// the subsequent Seed will surface the real error.
func mustListStages(s *store.Stages, r *http.Request, runID int64) []model.Stage {
	rows, err := s.ListForRun(r.Context(), runID)
	if err != nil {
		return nil
	}
	return rows
}

// ===== Phase 3 endpoints =================================================

// LogBatch is what the agent POSTs to /log: zero or more lines with
// timestamp + level + text. Lines are written in order to the per-run
// file and fanned out on the SSE hub.
type LogBatch struct {
	Lines []LogLine `json:"lines"`
}

type LogLine struct {
	TS    string `json:"ts,omitempty"`    // RFC3339Nano; server clock used if empty
	Level string `json:"level,omitempty"` // info|warn|error|debug
	Text  string `json:"text"`
}

// Log accepts a batch of log lines from the agent. Empty batches are
// legal (useful for agent-side flush ping).
func (a *Agent) Log(w http.ResponseWriter, r *http.Request) {
	runID, ok := runIDFromURL(w, r)
	if !ok {
		return
	}
	if _, ok := a.authenticate(w, r, runID); !ok {
		return
	}
	var batch LogBatch
	if err := json.NewDecoder(r.Body).Decode(&batch); err != nil {
		http.Error(w, "bad json", http.StatusBadRequest)
		return
	}
	writer, err := a.Logs.WriterFor(runID)
	if err != nil {
		http.Error(w, "open log: "+err.Error(), http.StatusInternalServerError)
		return
	}
	for _, l := range batch.Lines {
		ts, _ := time.Parse(time.RFC3339Nano, l.TS)
		writer.Append(logs.Line{TS: ts, Level: l.Level, Text: l.Text})
	}
	writeJSON(w, http.StatusOK, map[string]any{"ok": true, "written": len(batch.Lines)})
}

// StageResult is the body of /result. Kind is the stage name (from
// DefaultStageOrder); Passed drives StageCompleted vs StageFailed.
// Inventory is optional and only set when kind == "Inventory" — the
// orchestrator persists it as an artifact and feeds it to spec.Diff.
type StageResult struct {
	Stage     string          `json:"stage"`
	Passed    bool            `json:"passed"`
	Summary   json.RawMessage `json:"summary,omitempty"`
	Inventory *spec.Inventory `json:"inventory,omitempty"`
	Message   string          `json:"message,omitempty"`
}

// Result receives a stage's outcome. Flow:
//  1. Mark the stage row passed/failed + record summary JSON.
//  2. For Inventory: persist the inventory artifact.
//  3. For Inventory (on pass): run spec diff server-side, persist rows,
//     bump the run into SpecValidate and immediately resolve SpecValidate
//     from that diff — the agent isn't involved in SpecValidate at all.
//  4. Transition the run via StageCompleted/StageFailed.
func (a *Agent) Result(w http.ResponseWriter, r *http.Request) {
	runID, ok := runIDFromURL(w, r)
	if !ok {
		return
	}
	run, ok := a.authenticate(w, r, runID)
	if !ok {
		return
	}
	var body StageResult
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		http.Error(w, "bad json", http.StatusBadRequest)
		return
	}
	body.Stage = strings.TrimSpace(body.Stage)
	if _, ok := orchestrator.StateForStage(body.Stage); !ok {
		http.Error(w, "unknown stage: "+body.Stage, http.StatusBadRequest)
		return
	}

	stageState := model.StagePassed
	if !body.Passed {
		stageState = model.StageFailed
	}
	summaryJSON := ""
	if len(body.Summary) > 0 {
		summaryJSON = string(body.Summary)
	}
	if err := a.Runner.CompleteStage(r.Context(), runID, body.Stage, stageState, summaryJSON); err != nil {
		http.Error(w, "complete stage: "+err.Error(), http.StatusInternalServerError)
		return
	}

	// Inventory-specific: persist artifact + compute spec diff.
	if body.Stage == "Inventory" && body.Inventory != nil {
		if err := a.persistInventory(r, run, body.Inventory); err != nil {
			log.Printf("persist inventory run %d: %v", runID, err)
		}
	}

	if !body.Passed {
		if err := a.Runs.SetFailedStage(r.Context(), runID, body.Stage); err != nil {
			log.Printf("set failed stage: %v", err)
		}
		if _, err := a.Runner.Transition(r.Context(), runID, orchestrator.TriggerStageFailed); err != nil {
			log.Printf("result: failed-transition run %d: %v", runID, err)
			http.Error(w, "transition", http.StatusConflict)
			return
		}
		hostName := a.hostNameFor(r.Context(), run.HostID)
		detail := body.Message
		if detail == "" {
			detail = "stage reported failure"
		}
		a.dispatchEvent(notify.Event{
			Kind:     notify.KindStageFailed,
			Severity: notify.SeverityCritical,
			RunID:    runID,
			HostName: hostName,
			Title:    fmt.Sprintf("[vetting] %s FAILED: %s", hostName, body.Stage),
			Body:     fmt.Sprintf("Run %d on %s failed at stage %s.\n%s", runID, hostName, body.Stage, detail),
			URL:      a.runLinkURL(runID),
		})
		writeJSON(w, http.StatusOK, map[string]any{"ok": true, "next_state": "FailedHolding"})
		return
	}

	// Passed: advance to the next stage in the pipeline.
	next, err := a.Runner.Transition(r.Context(), runID, orchestrator.TriggerStageCompleted)
	if err != nil {
		http.Error(w, "advance: "+err.Error(), http.StatusConflict)
		return
	}
	log.Printf("result: run %d stage %s passed → %s", runID, body.Stage, next)

	// If the just-advanced-into state is SpecValidate or Reporting, the
	// orchestrator owns those stages entirely. The resolve function may
	// transition further (→ next stage on pass, → FailedHolding on fail,
	// → Completed for Reporting), so we re-read the run after each.
	if next == model.StateSpecValidate {
		a.resolveSpecValidate(r, runID)
		if after, err := a.Runs.Get(r.Context(), runID); err == nil {
			next = after.State
		}
	}
	if next == model.StateReporting {
		a.resolveReporting(r, runID)
		if after, err := a.Runs.Get(r.Context(), runID); err == nil {
			next = after.State
		}
	}
	writeJSON(w, http.StatusOK, map[string]any{"ok": true, "next_state": string(next)})
}

func (a *Agent) persistInventory(r *http.Request, run *model.Run, inv *spec.Inventory) error {
	dir := filepath.Join(a.ArtifactsDir, fmt.Sprintf("run-%d", run.ID))
	if err := os.MkdirAll(dir, 0o755); err != nil {
		return err
	}
	path := filepath.Join(dir, "inventory.json")
	buf, err := json.MarshalIndent(inv, "", "  ")
	if err != nil {
		return err
	}
	if err := os.WriteFile(path, buf, 0o644); err != nil {
		return err
	}
	sum := sha256.Sum256(buf)
	_, err = a.Artifacts.Create(r.Context(), store.Artifact{
		RunID:     run.ID,
		Kind:      "inventory",
		Path:      path,
		SHA256:    hex.EncodeToString(sum[:]),
		SizeBytes: int64(len(buf)),
	})
	return err
}

// resolveSpecValidate runs the expected-vs-actual diff against the
// just-stored inventory artifact, persists spec_diffs rows, and drives
// the state machine — all on the server. The agent does nothing for
// this stage.
func (a *Agent) resolveSpecValidate(r *http.Request, runID int64) {
	run, err := a.Runs.Get(r.Context(), runID)
	if err != nil {
		log.Printf("specvalidate: get run: %v", err)
		return
	}
	host, err := a.Hosts.Get(r.Context(), run.HostID)
	if err != nil {
		log.Printf("specvalidate: get host: %v", err)
		return
	}
	expected, err := spec.Parse(host.ExpectedSpecYAML)
	if err != nil {
		log.Printf("specvalidate: parse expected yaml: %v", err)
		a.failStage(r, runID, "SpecValidate", "malformed expected spec: "+err.Error())
		return
	}
	inv, err := a.readInventoryArtifact(r, runID)
	if err != nil {
		log.Printf("specvalidate: read inventory: %v", err)
		a.failStage(r, runID, "SpecValidate", "missing inventory artifact")
		return
	}
	diffs := spec.Diff(expected, inv)
	if err := a.SpecDiffs.ReplaceForRun(r.Context(), runID, diffs); err != nil {
		log.Printf("specvalidate: write diffs: %v", err)
	}
	if err := a.Stages.StartByName(r.Context(), runID, "SpecValidate"); err != nil {
		log.Printf("specvalidate: start stage: %v", err)
	}

	critical := 0
	for _, d := range diffs {
		if d.Severity == "critical" && !d.Ignored {
			critical++
		}
	}
	summaryBuf, _ := json.Marshal(map[string]any{
		"diffs":    len(diffs),
		"critical": critical,
	})
	if critical > 0 {
		_ = a.Runner.CompleteStage(r.Context(), runID, "SpecValidate", model.StageFailed, string(summaryBuf))
		_ = a.Runs.SetFailedStage(r.Context(), runID, "SpecValidate")
		if _, err := a.Runner.Transition(r.Context(), runID, orchestrator.TriggerStageFailed); err != nil {
			log.Printf("specvalidate: failed-transition: %v", err)
		}
		a.appendLog(runID, "error", fmt.Sprintf("SpecValidate: %d critical diff(s) — holding host", critical))
		hostName := a.hostNameFor(r.Context(), run.HostID)
		a.dispatchEvent(notify.Event{
			Kind:     notify.KindSpecMismatch,
			Severity: notify.SeverityCritical,
			RunID:    runID,
			HostName: hostName,
			Title:    fmt.Sprintf("[vetting] %s spec mismatch (%d critical)", hostName, critical),
			Body:     fmt.Sprintf("SpecValidate found %d critical diff(s) on %s. Host is held for inspection.", critical, hostName),
			URL:      a.runLinkURL(runID),
		})
	} else {
		_ = a.Runner.CompleteStage(r.Context(), runID, "SpecValidate", model.StagePassed, string(summaryBuf))
		if _, err := a.Runner.Transition(r.Context(), runID, orchestrator.TriggerStageCompleted); err != nil {
			log.Printf("specvalidate: advance: %v", err)
		}
		a.appendLog(runID, "info", "SpecValidate: all fields match expected spec")
	}
}

func (a *Agent) readInventoryArtifact(r *http.Request, runID int64) (*spec.Inventory, error) {
	arts, err := a.Artifacts.ListForRun(r.Context(), runID)
	if err != nil {
		return nil, err
	}
	for i := len(arts) - 1; i >= 0; i-- {
		if arts[i].Kind == "inventory" {
			buf, err := os.ReadFile(arts[i].Path)
			if err != nil {
				return nil, err
			}
			var inv spec.Inventory
			if err := json.Unmarshal(buf, &inv); err != nil {
				return nil, err
			}
			return &inv, nil
		}
	}
	return nil, errors.New("no inventory artifact")
}

func (a *Agent) failStage(r *http.Request, runID int64, stage, message string) {
	_ = a.Runner.CompleteStage(r.Context(), runID, stage, model.StageFailed, fmt.Sprintf(`{"error":%q}`, message))
	_ = a.Runs.SetFailedStage(r.Context(), runID, stage)
	if _, err := a.Runner.Transition(r.Context(), runID, orchestrator.TriggerStageFailed); err != nil {
		log.Printf("failStage: transition run %d: %v", runID, err)
	}
	a.appendLog(runID, "error", stage+": "+message)
}

func (a *Agent) appendLog(runID int64, level, text string) {
	if a.Logs == nil {
		return
	}
	w, err := a.Logs.WriterFor(runID)
	if err != nil {
		log.Printf("appendLog: %v", err)
		return
	}
	w.Append(logs.Line{Level: level, Text: text})
}

// Hold issues the per-run ephemeral ed25519 keypair: the agent gets
// the authorized_keys line, the orchestrator keeps the privkey on disk.
// Hold also records the agent's reported IP so the tile can print the
// ssh invocation.
type HoldRequest struct {
	AgentIP string `json:"agent_ip"`
}

type HoldResponse struct {
	AuthorizedKey string `json:"authorized_key"`
	RunID         int64  `json:"run_id"`
}

func (a *Agent) Hold(w http.ResponseWriter, r *http.Request) {
	runID, ok := runIDFromURL(w, r)
	if !ok {
		return
	}
	if _, ok := a.authenticate(w, r, runID); !ok {
		return
	}
	var body HoldRequest
	_ = json.NewDecoder(r.Body).Decode(&body)
	agentIP := strings.TrimSpace(body.AgentIP)
	if agentIP == "" {
		if host, _, err := net.SplitHostPort(r.RemoteAddr); err == nil {
			agentIP = host
		}
	}
	if agentIP != "" {
		if err := a.Runs.SetHoldIP(r.Context(), runID, agentIP); err != nil {
			log.Printf("hold: set hold_ip: %v", err)
		}
	}

	kp, err := hold.Issue(runID)
	if err != nil {
		http.Error(w, "generate key: "+err.Error(), http.StatusInternalServerError)
		return
	}
	keyPath := filepath.Join(a.ArtifactsDir, fmt.Sprintf("run-%d", runID), "hold.key")
	abs, err := kp.WritePrivateTo(keyPath)
	if err != nil {
		http.Error(w, "write key: "+err.Error(), http.StatusInternalServerError)
		return
	}
	sum := sha256.Sum256(kp.PrivatePEM)
	if _, err := a.Artifacts.Create(r.Context(), store.Artifact{
		RunID:     runID,
		Kind:      "hold_key",
		Path:      abs,
		SHA256:    hex.EncodeToString(sum[:]),
		SizeBytes: int64(len(kp.PrivatePEM)),
	}); err != nil {
		log.Printf("hold: record artifact: %v", err)
	}
	a.appendLog(runID, "info", fmt.Sprintf("Hold key issued. SSH in with: ssh -i %s root@%s", abs, agentIP))
	hostID := mustHostID(a, r, runID)
	if hostID != 0 {
		hostName := a.hostNameFor(r.Context(), hostID)
		a.dispatchEvent(notify.Event{
			Kind:     notify.KindHoldingOpened,
			Severity: notify.SeverityCritical,
			RunID:    runID,
			HostName: hostName,
			Title:    fmt.Sprintf("[vetting] %s holding — SSH ready", hostName),
			Body:     fmt.Sprintf("Host %s is holding at %s.\nssh -i %s root@%s", hostName, agentIP, abs, agentIP),
			URL:      a.runLinkURL(runID),
		})
	}
	// Refresh the tile so the operator sees the ssh command.
	host, _ := a.Hosts.Get(r.Context(), mustHostID(a, r, runID))
	if host != nil {
		latest, _ := a.Runs.Get(r.Context(), runID)
		if orchestrator.TileRenderer != nil {
			payload := orchestrator.TileRenderer(r.Context(), *host, latest)
			a.EventHub.Publish(events.Event{Name: fmt.Sprintf("tile-%d", host.ID), Payload: payload})
		}
	}
	writeJSON(w, http.StatusOK, HoldResponse{AuthorizedKey: kp.AuthorizedKey, RunID: runID})
}

// dispatchEvent hands an already-populated Event to the notify Registry
// if one is wired. Handler code uses hostNameFor to resolve the host
// name for the event payload; this keeps call sites terse.
func (a *Agent) dispatchEvent(ev notify.Event) {
	if a.Notify == nil {
		return
	}
	a.Notify.Dispatch(ev)
}

// hostNameFor returns a human-readable host name for a run, or "host-N"
// if the lookup fails — notifications should never fail silently over a
// missing name.
func (a *Agent) hostNameFor(ctx context.Context, hostID int64) string {
	if host, err := a.Hosts.Get(ctx, hostID); err == nil && host != nil {
		return host.Name
	}
	return fmt.Sprintf("host-%d", hostID)
}

func (a *Agent) runLinkURL(runID int64) string {
	if a.PublicURL == "" {
		return ""
	}
	return strings.TrimRight(a.PublicURL, "/") + "/reports/" + fmt.Sprintf("%d", runID)
}

func mustHostID(a *Agent, r *http.Request, runID int64) int64 {
	run, err := a.Runs.Get(r.Context(), runID)
	if err != nil || run == nil {
		return 0
	}
	return run.HostID
}

// ===== Phase 4 endpoints =================================================

// SensorBatch is what the agent POSTs to /sensor: a stream of numeric
// samples (temps, fan rpm, PSU rails, iperf throughput). Each sample is
// (kind, key, value, unit). Timestamps default to server-now when empty
// so the thermal sidecar doesn't have to carry a clock.
type SensorBatch struct {
	Samples []SensorSample `json:"samples"`
}

type SensorSample struct {
	TS    string  `json:"ts,omitempty"`
	Kind  string  `json:"kind"` // temp|fan|psu_volt|iperf|fio|smart_attr
	Key   string  `json:"key"`
	Value float64 `json:"value"`
	Unit  string  `json:"unit,omitempty"`
}

// Sensor persists a batch of numeric samples. The thermal sidecar hits
// this on a tick; stage executors (iperf, fio) also drop here.
func (a *Agent) Sensor(w http.ResponseWriter, r *http.Request) {
	runID, ok := runIDFromURL(w, r)
	if !ok {
		return
	}
	if _, ok := a.authenticate(w, r, runID); !ok {
		return
	}
	if a.Measurements == nil {
		http.Error(w, "measurements store not wired", http.StatusInternalServerError)
		return
	}
	var body SensorBatch
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		http.Error(w, "bad json", http.StatusBadRequest)
		return
	}
	rows := make([]model.Measurement, 0, len(body.Samples))
	for _, s := range body.Samples {
		ts, _ := time.Parse(time.RFC3339Nano, s.TS)
		rows = append(rows, model.Measurement{
			RunID: runID,
			TS:    ts,
			Kind:  s.Kind,
			Key:   s.Key,
			Value: s.Value,
			Unit:  s.Unit,
		})
	}
	if err := a.Measurements.CreateBatch(r.Context(), rows); err != nil {
		http.Error(w, "write samples: "+err.Error(), http.StatusInternalServerError)
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{"ok": true, "written": len(rows)})
}

// resolveReporting runs when the pipeline advances into StateReporting.
// It's an orchestrator-owned stage like SpecValidate: no agent action.
// Writes a JSON report bundling run + stages + diffs + measurements,
// then advances the run to Completed. Heartbeat will then return abort
// and the agent will power the host off in Phase 5.
func (a *Agent) resolveReporting(r *http.Request, runID int64) {
	ctx := r.Context()
	if err := a.Stages.StartByName(ctx, runID, "Reporting"); err != nil {
		log.Printf("reporting: start stage: %v", err)
	}
	run, err := a.Runs.Get(ctx, runID)
	if err != nil {
		log.Printf("reporting: get run: %v", err)
		return
	}
	host, err := a.Hosts.Get(ctx, run.HostID)
	if err != nil {
		log.Printf("reporting: get host: %v", err)
		return
	}
	stages, err := a.Stages.ListForRun(ctx, runID)
	if err != nil {
		log.Printf("reporting: list stages: %v", err)
	}
	diffs, err := a.SpecDiffs.ListForRun(ctx, runID)
	if err != nil {
		log.Printf("reporting: list diffs: %v", err)
	}
	var measurements []model.Measurement
	if a.Measurements != nil {
		measurements, err = a.Measurements.ListForRun(ctx, runID)
		if err != nil {
			log.Printf("reporting: list measurements: %v", err)
		}
	}
	bundle := map[string]any{
		"run":          run,
		"host":         host,
		"stages":       stages,
		"spec_diffs":   diffs,
		"measurements": measurements,
		"generated_at": time.Now().UTC().Format(time.RFC3339),
	}
	buf, err := json.MarshalIndent(bundle, "", "  ")
	if err != nil {
		log.Printf("reporting: marshal: %v", err)
		a.failStage(r, runID, "Reporting", "marshal report: "+err.Error())
		return
	}
	dir := filepath.Join(a.ArtifactsDir, fmt.Sprintf("run-%d", runID))
	if err := os.MkdirAll(dir, 0o755); err != nil {
		a.failStage(r, runID, "Reporting", "mkdir: "+err.Error())
		return
	}
	path := filepath.Join(dir, "report.json")
	if err := os.WriteFile(path, buf, 0o644); err != nil {
		a.failStage(r, runID, "Reporting", "write: "+err.Error())
		return
	}
	sum := sha256.Sum256(buf)
	if _, err := a.Artifacts.Create(ctx, store.Artifact{
		RunID:     runID,
		Kind:      "report",
		Path:      path,
		SHA256:    hex.EncodeToString(sum[:]),
		SizeBytes: int64(len(buf)),
	}); err != nil {
		log.Printf("reporting: record artifact: %v", err)
	}
	// Also render the operator-facing HTML summary alongside the JSON.
	// Failures here are non-fatal — the JSON is the source of truth.
	if host != nil {
		htmlData := report.Data{
			GeneratedAt: time.Now().UTC(),
			Run:         *run,
			Host:        *host,
			Stages:      stages,
			SpecDiffs:   diffs,
			Aggregates:  report.AggregateMeasurements(measurements),
		}
		if htmlBuf, err := report.RenderHTML(htmlData); err != nil {
			log.Printf("reporting: render html: %v", err)
		} else {
			htmlPath := filepath.Join(dir, "report.html")
			if err := os.WriteFile(htmlPath, htmlBuf, 0o644); err != nil {
				log.Printf("reporting: write html: %v", err)
			} else {
				htmlSum := sha256.Sum256(htmlBuf)
				if _, err := a.Artifacts.Create(ctx, store.Artifact{
					RunID:     runID,
					Kind:      "report_html",
					Path:      htmlPath,
					SHA256:    hex.EncodeToString(htmlSum[:]),
					SizeBytes: int64(len(htmlBuf)),
				}); err != nil {
					log.Printf("reporting: record html artifact: %v", err)
				}
			}
		}
	}
	summaryBuf, _ := json.Marshal(map[string]any{
		"report_path": path,
		"stages":      len(stages),
		"diffs":       len(diffs),
	})
	if err := a.Runner.CompleteStage(ctx, runID, "Reporting", model.StagePassed, string(summaryBuf)); err != nil {
		log.Printf("reporting: complete stage: %v", err)
	}
	if err := a.Runs.MarkCompleted(ctx, runID, path); err != nil {
		log.Printf("reporting: mark completed: %v", err)
	}
	a.appendLog(runID, "info", "Reporting: wrote "+path+"; run completed.")
	// Publish a final tile update so the dashboard flips to pass mood.
	if host != nil && orchestrator.TileRenderer != nil {
		latest, _ := a.Runs.Get(ctx, runID)
		payload := orchestrator.TileRenderer(ctx, *host, latest)
		a.EventHub.Publish(events.Event{Name: fmt.Sprintf("tile-%d", host.ID), Payload: payload})
	}
	hostName := "host"
	if host != nil {
		hostName = host.Name
	}
	a.dispatchEvent(notify.Event{
		Kind:     notify.KindRunCompleted,
		Severity: notify.SeverityInfo,
		RunID:    runID,
		HostName: hostName,
		Title:    fmt.Sprintf("[vetting] %s passed vetting", hostName),
		Body:     fmt.Sprintf("Run %d on %s completed all stages. Report: %s", runID, hostName, path),
		URL:      a.runLinkURL(runID),
	})
}