package templates

import (
	"bytes"
	"context"
	"fmt"
	"time"

	"vetting/internal/model"
)

// HostTile renders a single dashboard card: hostname, heartbeat badge,
// latest run status, and the primary action (Start / Cancel / View
// report). The whole tile is a link to /hosts/{id} via a CSS-overlay
// <a>; every deeper control lives on the host page or the run page.
// It's the SSE-swap target for per-host tile refreshes (`tile-N`).
templ HostTile(t TileData) {
	<article
		id={ fmt.Sprintf("host-%d", t.Host.ID) }
		class={ "tile", "tile-" + tileMood(t.Latest) }
		sse-swap={ fmt.Sprintf("tile-%d", t.Host.ID) }
		hx-swap="outerHTML"
	>
		<a class="tile-link" href={ templ.SafeURL(fmt.Sprintf("/hosts/%d", t.Host.ID)) } aria-label={ "Open " + t.Host.Name }></a>
		<header class="tile-head">
			<div class="tile-name">{ t.Host.Name }</div>
			<div class="tile-header-right">
				<span class={ "tile-last-seen", lastSeenClass(t.LastSeenAt) }>{ lastSeenLabel(t.LastSeenAt) }</span>
				<div class="tile-status">{ tileStatus(t.Latest) }</div>
			</div>
		</header>
		<div class="tile-primary-action">
			if canStart(t) {
				<form method="post" action={ templ.SafeURL(fmt.Sprintf("/hosts/%d/start", t.Host.ID)) } class="inline tile-start-form">
					<label class="tile-nd-toggle">
						<input type="checkbox" name="non_destructive" value="1"/>
						Non-destructive
					</label>
					<button type="submit">Start vetting</button>
				</form>
			} else if canStartIfOnline(t.Latest) {
				<button type="button" disabled title="host is not heartbeating — install the reporter via /register/quick.sh on the target host">Start vetting</button>
			} else if canCancel(t.Latest) {
				<form method="post" action={ templ.SafeURL(fmt.Sprintf("/hosts/%d/cancel", t.Host.ID)) } class="inline tile-cancel-form" onsubmit="return confirm('Cancel run? Destructive stages may leave the host in an intermediate state requiring manual cleanup.');">
					<button type="submit" class="danger">Cancel run</button>
				</form>
			} else if hasReport(t.Latest) {
				<a class="button-like" href={ templ.SafeURL(fmt.Sprintf("/reports/%d", t.Latest.ID)) } target="_blank" rel="noopener">View report</a>
			}
		</div>
	</article>
}

func canOverrideWipe(r *model.Run) bool {
	if r == nil {
		return false
	}
	return r.State == model.StateFailedHolding && r.FailedStage == "Storage"
}

// hasReport is true once the reporting stage has produced an HTML
// artifact. We cheat slightly: Completed runs always have one, and
// that's the only state in which the tile wants to surface a link.
func hasReport(r *model.Run) bool {
	return r != nil && r.State == model.StateCompleted
}

// canStart gates the Start button on two things: the run is in a state
// that accepts a fresh start, AND the host is currently heartbeating.
// The heartbeat check mirrors the StartRun handler's preflight so the
// button never offers a click that the server would reject with 409.
func canStart(t TileData) bool {
	if !canStartIfOnline(t.Latest) {
		return false
	}
	if t.LastSeenAt == nil {
		return false
	}
	return time.Since(*t.LastSeenAt) <= 60*time.Second
}

// canStartIfOnline is the run-state half of canStart, split out so the
// template can distinguish "waiting on run to end" (no button) from
// "run is done but host is offline" (disabled button with tooltip).
func canStartIfOnline(r *model.Run) bool {
	if r == nil {
		return true
	}
	return r.State.IsTerminal()
}

// canCancel is true for any non-terminal run, plus FailedHolding —
// a held run technically classifies as terminal for the pipeline but
// the host is still live on the SSH hold prompt, and the operator
// can walk away from it via Cancel (which reboots to local disk).
// Every other terminal state is truly done, so no Cancel button.
// The server-side CancelRun handler mirrors this predicate.
func canCancel(r *model.Run) bool {
	if r == nil {
		return false
	}
	if !r.State.IsTerminal() {
		return true
	}
	return r.State == model.StateFailedHolding
}

func tileStatus(r *model.Run) string {
	if r == nil {
		return "Idle"
	}
	switch r.State {
	case model.StateWaitingReboot:
		return "Waiting for reboot"
	}
	if cancelledFromHold(r) {
		return "Failed (cancelled)"
	}
	return string(r.State)
}

func tileMood(r *model.Run) string {
	if r == nil {
		return "idle"
	}
	if cancelledFromHold(r) {
		return "fail"
	}
	switch r.State {
	case model.StateCompleted:
		return "pass"
	case model.StateFailed, model.StateFailedHolding:
		return "fail"
	case model.StateReleased, model.StateCancelled:
		return "idle"
	}
	return "active"
}

// cancelledFromHold is true when a FailedHolding run was later Cancelled
// by the operator (tracked by State=Cancelled with FailedStage still
// set — mid-stage cancels don't stamp FailedStage). These deserve a
// fail-colored tile because the run did fail; the cancel was just the
// operator choosing not to recover.
func cancelledFromHold(r *model.Run) bool {
	return r != nil && r.State == model.StateCancelled && r.FailedStage != ""
}

func sshInvocation(keyPath, ip string) string {
	if keyPath == "" {
		return "ssh root@" + ip + "  (hold key not yet recorded)"
	}
	return fmt.Sprintf("ssh -i %s root@%s", keyPath, ip)
}

// RenderTileString renders a single tile fragment so the orchestrator
// can publish it over SSE without threading a context through every
// event publisher.
func RenderTileString(t TileData) string {
	var buf bytes.Buffer
	_ = HostTile(t).Render(context.Background(), &buf)
	return buf.String()
}

// lastSeenLabel renders the host-mode agent's liveness into a short
// badge: "never" if the host has never heartbeated, "online" within
// a 2×heartbeat grace window (60s, since agents heartbeat every 30s),
// "Nm ago" / "Nh ago" / "Nd ago" otherwise.
func lastSeenLabel(t *time.Time) string {
	if t == nil {
		return "never"
	}
	return humanAgoFrom(time.Now(), *t)
}

// lastSeenClass pairs with lastSeenLabel to drive the badge color
// without the template having to carry its own logic.
func lastSeenClass(t *time.Time) string {
	if t == nil {
		return "offline"
	}
	if time.Since(*t) < 60*time.Second {
		return "online"
	}
	return "stale"
}

// humanAgoFrom formats (now - t) as a short "Nm ago" style string.
// Buckets: <60s -> "online", <60m -> minutes, <24h -> hours, else days.
// Split on `now` so callers can hold time for tests.
func humanAgoFrom(now time.Time, t time.Time) string {
	d := now.Sub(t)
	if d < 0 {
		d = 0
	}
	if d < 60*time.Second {
		return "online"
	}
	if d < time.Hour {
		return fmt.Sprintf("%dm ago", int(d/time.Minute))
	}
	if d < 24*time.Hour {
		return fmt.Sprintf("%dh ago", int(d/time.Hour))
	}
	return fmt.Sprintf("%dd ago", int(d/(24*time.Hour)))
}