package calls

import (
	"html/template"
	"testing"

	"amadan.net/rastrillo/rastrillo/ui"

	"amadan.net/oficina/calls/internal/calls/icons"
)

// buildPage parses rastrillo's vendored ui partials and this app's own
// templates/partials/ into one template set, and html/template resolves
// a name by taking the last definition it parsed. So an app partial that
// happens to define a name the framework already defines does not
// collide, does not warn and does not fail to build: it silently
// replaces the vendored one for every page in the app, and the first
// anyone hears of it is a screen that looks wrong somewhere else
// entirely.
//
// The names are not obscure ones to reach for either — "field",
// "badge", "person", "stat", "callout" are all vendored, and all are
// exactly what someone would call a new partial of their own. This test
// is the warning that parse order will not give.
//
// It compares every defined name, not just the {{define}} blocks:
// ParseFS also defines a template per file under its base name, so
// naming an app partial field-text.html would shadow the vendored
// partial's file entry the same way.
func TestAppPartialsDoNotShadowAVendoredUIPartial(t *testing.T) {
	funcs := func(tpl *template.Template) *template.Template {
		return tpl.
			Funcs(ui.Funcs(ui.WithIcons(icons.Icon, icons.Assets))).
			Funcs(template.FuncMap{"asset": assets.Path})
	}

	const root = "shadow-probe"
	vendored := template.Must(funcs(template.New(root)).ParseFS(ui.Templates(), "*.html"))
	taken := map[string]bool{}
	for _, tpl := range vendored.Templates() {
		if tpl.Name() != root {
			taken[tpl.Name()] = true
		}
	}
	if len(taken) == 0 {
		t.Fatal("no vendored ui partials were parsed — this test would pass on anything")
	}

	own := template.Must(funcs(template.New(root)).ParseFS(appFS, "templates/partials/*.html"))
	found := 0
	for _, tpl := range own.Templates() {
		name := tpl.Name()
		if name == root {
			continue
		}
		found++
		if taken[name] {
			t.Errorf("templates/partials/ defines %q, which rastrillo's ui already defines: "+
				"buildPage parses ui first, so this app's definition silently wins for every page. Rename it.", name)
		}
	}
	if found == 0 {
		t.Fatal("no app partials were parsed — templates/partials/ moved, and this test now proves nothing")
	}
}