// Package app holds the go-wasm-web example's pages and components as
// standalone, platform-neutral functions (SSR on the server, hydrate on the
// client). UI is built from the kjol webui kit + Tailwind utility classes.
//
// Directives (processed by kjol/cmd/wasmgen at build time):
//
//	//gowasm:page <path> [static] [layout=<name>]  a route (static => SSR'd)
//	//gowasm:layout <name>                          a func(Deps, *VNode) *VNode wrapper
//	//gowasm:server                                 (see server_counter.go) a server component
package app

//go:generate go run kjol/cmd/wasmgen .

import (
	"strconv"

	. "kjol/vdom"
	ui "kjol/webui"
)

// Deps are the client-only capabilities, injected so pages stay neutral.
type Deps struct {
	Path     func() string
	Navigate func(string)
}

func itoa(n int) string { return strconv.Itoa(n) }

// Layout wraps a page's content with shared chrome (declared with //gowasm:layout,
// selected per route via `layout=`; the generated LayoutFor dispatches by name).
type Layout func(d Deps, content *VNode) *VNode

// Shell renders the current route's page inside its declared layout.
func Shell(d Deps, routes map[string]func() *VNode) *VNode {
	path := d.Path()
	var content *VNode
	if page := routes[path]; page != nil {
		content = page()
	} else {
		content = notFound(path)
	}
	return LayoutFor(d, path, content)
}

func notFound(path string) *VNode {
	return Div(Attr("class", "py-10"),
		H2(Attr("class", "text-xl font-semibold text-neutral-800 mb-2"), Text("Page not found")),
		P(Attr("class", "text-neutral-500"), Text("No route matches "+path+".")),
	)
}

// --- layouts (Tailwind chrome) -------------------------------------------

//gowasm:layout public
func PublicLayout(d Deps, content *VNode) *VNode {
	return Div(
		Nav(Attr("class", "site-nav sticky top-0 z-10 border-b border-neutral-200 bg-white"),
			Div(Attr("class", "mx-auto flex max-w-5xl items-center gap-2 px-4 py-3"),
				A(Attr("class", "text-lg font-semibold tracking-tight text-text-heading no-underline"), Attr("href", "/"), navigate(d, "/"), Text("gowasm")),
				Ul(Attr("class", "ml-auto flex items-center gap-1"),
					navItem(d, "/", "Home", false),
					navItem(d, "/about", "About", false),
					Li(Attr("class", "ml-2"),
						A(Attr("class", "inline-flex items-center gap-1 rounded-default bg-primary px-3 py-1.5 text-sm font-medium text-white no-underline hover:bg-primary-hover"),
							Attr("href", "/chart"), navigate(d, "/chart"), Text("Open app →"))),
				))),
		Main(Attr("class", "mx-auto max-w-5xl px-4 py-8"),
			content,
			Footer(Attr("class", "mt-12 border-t border-neutral-200 pt-4 text-sm text-neutral-400"),
				Text("gowasm — pure-Go components compiled to WebAssembly.")),
		),
	)
}

//gowasm:layout app
func AppLayout(d Deps, content *VNode) *VNode {
	return Div(Attr("class", "min-h-screen"),
		Nav(Attr("class", "app-nav border-b border-neutral-800 bg-neutral-900"),
			Div(Attr("class", "mx-auto flex max-w-5xl items-center gap-2 px-4 py-3"),
				A(Attr("class", "text-lg font-semibold tracking-tight text-text-on-dark no-underline"), Attr("href", "/chart"), navigate(d, "/chart"), Text("gowasm · app")),
				Ul(Attr("class", "ml-4 flex items-center gap-1"),
					navItem(d, "/chart", "Chart", true),
					navItem(d, "/server", "Server", true),
					navItem(d, "/kit", "UI Kit", true)),
				Ul(Attr("class", "ml-auto flex items-center"),
					navItem(d, "/", "Home", true)),
			)),
		Main(Attr("class", "mx-auto max-w-5xl px-4 py-8"), content),
	)
}

// navItem is a nav link with an active state; dark switches to on-dark colors.
func navItem(d Deps, path, label string, dark bool) *VNode {
	active := d.Path() == path
	var cls string
	switch {
	case dark && active:
		cls = "active rounded-default px-3 py-1.5 text-sm font-medium bg-white/10 text-white"
	case dark:
		cls = "rounded-default px-3 py-1.5 text-sm font-medium text-neutral-300 hover:bg-white/5 hover:text-white"
	case active:
		cls = "active rounded-default px-3 py-1.5 text-sm font-medium bg-neutral-100 text-neutral-900"
	default:
		cls = "rounded-default px-3 py-1.5 text-sm font-medium text-neutral-600 hover:bg-neutral-100 hover:text-neutral-900"
	}
	return Li(A(Attr("class", cls+" no-underline"), Attr("href", path), navigate(d, path), Text(label)))
}

// navigate intercepts a link click for client-side SPA navigation (Navigate is
// nil on the server, so the anchor falls back to a normal navigation).
func navigate(d Deps, path string) Mod {
	return OnEvent(EVENT_CLICK, func(e Event) {
		if d.Navigate != nil {
			e.PreventDefault()
			d.Navigate(path)
		}
	})
}

// Counter is a presentational client component; state is owned by the caller.
func Counter(label string, count *Signal[int]) *VNode {
	return Div(Attr("class", "counter flex items-center gap-3 rounded-default border border-neutral-200 bg-white px-4 py-3 shadow-xs"),
		Span(Attr("class", "font-medium text-neutral-700"), Text(label+": ")),
		Strong(Attr("class", "badge inline-flex min-w-8 items-center justify-center rounded-full bg-primary px-2.5 py-0.5 text-sm font-semibold text-white"), Text(itoa(count.Get()))),
		Div(Attr("class", "ml-auto flex gap-1"),
			ui.Button(ui.ButtonProps{Color: ui.ButtonSecondary, Small: true, Text: "−", OnClick: func() { count.Update(func(v int) int { return v - 1 }) }}),
			ui.Button(ui.ButtonProps{Color: ui.ButtonPrimary, Small: true, Text: "+", OnClick: func() { count.Update(func(v int) int { return v + 1 }) }}),
		),
	)
}

//gowasm:page / static layout=public
func HomePage(d Deps) func() *VNode {
	a := NewSignal(0)
	b := NewSignal(0)
	dark := NewSignal(false)
	return func() *VNode {
		return Div(Attr("class", "space-y-8"),
			Div(
				H2(Attr("class", "text-2xl font-semibold tracking-tight text-text-heading"), Text("Home — component composition")),
				P(Attr("class", "mt-1 text-neutral-500"), Text("Two counters; the total is derived across them. Server-rendered, then hydrated.")),
			),
			Div(Attr("class", "grid gap-3 sm:grid-cols-2"),
				Counter("Apples", a),
				Counter("Bananas", b),
			),
			ui.Alert(ui.AlertBlue, "",
				Span(Text("Combined total: ")),
				Strong(Attr("class", "font-semibold"), Text(itoa(a.Get()+b.Get()))),
			),
			ui.Card("",
				ui.CardHeader("", Text("webui kit")),
				Div(Attr("class", "flex flex-wrap items-center gap-2"),
					ui.Button(ui.ButtonProps{Color: ui.ButtonPrimary, Text: "Primary"}),
					ui.Button(ui.ButtonProps{Color: ui.ButtonGreen, Text: "Green"}),
					ui.Button(ui.ButtonProps{Color: ui.ButtonRed, Outline: true, Text: "Danger"}),
					ui.Button(ui.ButtonProps{Color: ui.ButtonNeutral, Small: true, Icon: "check", Text: "Small"}),
					ui.Badge(ui.BadgeProps{Color: ui.BadgeGreen}, Text("active")),
					ui.Badge(ui.BadgeProps{Color: ui.BadgeAmber, Pill: true}, Text("pending")),
				),
				Div(Attr("class", "mt-4"),
					ui.ToggleSwitch(dark.Get(), func(v bool) { dark.Set(v) }, "Dark mode", "Just a demo toggle", false, "")),
			),
		)
	}
}

//gowasm:page /about static layout=public
func AboutPage(d Deps) func() *VNode {
	return func() *VNode {
		return Div(Attr("class", "space-y-6"),
			H2(Attr("class", "text-2xl font-semibold tracking-tight text-text-heading"), Text("About")),
			ui.Card("",
				P(Attr("class", "text-neutral-600 leading-relaxed"),
					Text("Components are standalone Go functions; calling a server component looks "+
						"identical to calling a client one — the //gowasm:server directive and the "+
						"build-time codegen wire up the round-trip. Static routes are SSR'd; the rest "+
						"render on the client. The UI kit (kjol/webui) is a Go port of the Solid.js "+
						"component kit, styled with Tailwind.")),
			),
			ui.Alert(ui.AlertGreen, "Neutral + isomorphic",
				Text("This page's markup runs on the server (SSR) and hydrates on the client from the same Go code.")),
		)
	}
}

//gowasm:page /server layout=app
func ServerPage(d Deps) func() *VNode {
	// ServerCounter is a server component — calling it is just like calling any
	// component. On the client this resolves to a generated stub that mounts it
	// over /rsc; on the server it's the real function.
	counter := ServerCounter()
	return func() *VNode {
		return Div(Attr("class", "space-y-6"),
			H2(Attr("class", "text-2xl font-semibold tracking-tight text-text-heading"), Text("Server component")),
			P(Attr("class", "text-neutral-500"),
				Text("This counter runs on the server. Its state lives there; clicks round-trip "+
					"and the returned render merges into the DOM.")),
			counter(),
		)
	}
}