package models

import (
	"strings"
	"testing"
)

func testRouter(t *testing.T) *Router {
	t.Helper()
	tiers := map[string]string{
		"mopac-study":   "glm-4.7-flash",
		"mopac-code":    "glm-5.2",
		"mopac-review":  "glm-5-turbo",
		"mopac-primary": "glm-5.3",
		"mopac-vision":  "glm-4.6v",
	}
	classes := map[string]string{
		"study":   "mopac-study",
		"read":    "mopac-study",
		"code":    "mopac-code",
		"review":  "mopac-review",
		"primary": "mopac-primary",
	}
	r, err := NewRouter(tiers, classes, "mopac-primary")
	if err != nil {
		t.Fatalf("NewRouter: %v", err)
	}
	return r
}

func TestResolve(t *testing.T) {
	cases := []struct {
		class string
		tier  string
		model string
	}{
		{"study", "mopac-study", "glm-4.7-flash"},
		{"read", "mopac-study", "glm-4.7-flash"},
		{"code", "mopac-code", "glm-5.2"},
		{"review", "mopac-review", "glm-5-turbo"},
		{"primary", "mopac-primary", "glm-5.3"},
		{"", "mopac-primary", "glm-5.3"}, // no class -> default tier
	}
	r := testRouter(t)
	for _, tc := range cases {
		d, err := r.Resolve(tc.class)
		if err != nil {
			t.Fatalf("Resolve(%q): %v", tc.class, err)
		}
		if d.Tier != tc.tier || d.Model != tc.model {
			t.Errorf("Resolve(%q) = %s/%s, want %s/%s", tc.class, d.Tier, d.Model, tc.tier, tc.model)
		}
	}
}

func TestResolveUnknownClassIsError(t *testing.T) {
	r := testRouter(t)
	_, err := r.Resolve("urgent")
	if err == nil {
		t.Fatal("unknown class must error (routing stays auditable)")
	}
	if !strings.Contains(err.Error(), `[models.classes]`) {
		t.Errorf("error should point at the config section: %v", err)
	}
}

func TestNewRouterValidation(t *testing.T) {
	tiers := map[string]string{"mopac-primary": "glm-5.3"}
	if _, err := NewRouter(tiers, nil, "mopac-missing"); err == nil || !strings.Contains(err.Error(), "default tier") {
		t.Errorf("missing default tier: err=%v", err)
	}
	if _, err := NewRouter(tiers, map[string]string{"x": "mopac-nope"}, "mopac-primary"); err == nil || !strings.Contains(err.Error(), "unknown tier") {
		t.Errorf("class to unknown tier: err=%v", err)
	}
	if _, err := NewRouter(nil, nil, "mopac-primary"); err == nil {
		t.Errorf("empty tiers must error")
	}
}

func TestClasses(t *testing.T) {
	// The serve front door builds its catalog from the sorted class list;
	// it must be complete and ordered for stable /v1/models output.
	got := testRouter(t).Classes()
	want := "code primary read review study"
	if strings.Join(got, " ") != want {
		t.Errorf("Classes() = %v, want %v", got, want)
	}
}