package wasmguest

import (
	"context"
	"errors"
	"strings"
	"testing"

	abiv1 "git.dev.alexdunmow.com/block/pluginsdk/abi/v1"
	"git.dev.alexdunmow.com/block/pluginsdk/blocks"
	"git.dev.alexdunmow.com/block/pluginsdk/plugin"
	"git.dev.alexdunmow.com/block/pluginsdk/templates"
	"google.golang.org/protobuf/proto"
)

// tagFilterRegistration registers a powered block plus a custom tag and
// filter, exercising the render-as-a-host-capability surface (RENDER_TAG,
// APPLY_FILTER, powered RENDER_BLOCK, and DESCRIBE declared_tags/filters).
func tagFilterRegistration() plugin.PluginRegistration {
	return plugin.PluginRegistration{
		Name:    "capfx",
		Version: "0.1.0",
		Register: func(_ templates.TemplateRegistry, br blocks.BlockRegistry) error {
			br.Register(blocks.BlockMeta{Key: "hero", Title: "Hero", Category: blocks.CategoryContent},
				func(ctx context.Context, content map[string]any) string {
					title, _ := content["title"].(string)
					// Powered: return template + data; the host renders it.
					return blocks.PoweredBlock("<h1>{{ title }}</h1>", map[string]any{"title": title})
				})
			blocks.RegisterTag("greet", func(args map[string]any, rctx blocks.RenderContext) (string, error) {
				who, _ := args["who"].(string)
				if who == "boom" {
					panic("tag kaboom")
				}
				if who == "err" {
					return "", errors.New("greet failed")
				}
				// Reads render context via the standard accessors.
				tpl := blocks.GetTemplateKey(rctx)
				return "hi " + who + " on " + tpl, nil
			})
			blocks.RegisterFilter("upper", func(input string, args map[string]any) (string, error) {
				if input == "err" {
					return "", errors.New("upper failed")
				}
				return strings.ToUpper(input), nil
			})
			return nil
		},
	}
}

func TestDescribeEmitsDeclaredTagsAndFilters(t *testing.T) {
	g := newGuest(tagFilterRegistration())
	resp := invokeHook(t, g, abiv1.Hook_HOOK_DESCRIBE, &abiv1.DescribeRequest{HostAbiVersion: 1})
	if resp.GetError() != nil {
		t.Fatalf("describe error: %v", resp.GetError())
	}
	dr := &abiv1.DescribeResponse{}
	if err := proto.Unmarshal(resp.GetPayload(), dr); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}
	m := dr.GetManifest()
	if got := m.GetDeclaredTags(); len(got) != 1 || got[0] != "greet" {
		t.Errorf("declared_tags = %v, want [greet]", got)
	}
	if got := m.GetDeclaredFilters(); len(got) != 1 || got[0] != "upper" {
		t.Errorf("declared_filters = %v, want [upper]", got)
	}
}

// TestDescribeTagRegistryIsPerGuest proves runRegister's reset isolates the
// package-level tag/filter registry per installed registration: a tag-free
// registration must describe zero tags even after a prior tag-registering one.
func TestDescribeTagRegistryIsPerGuest(t *testing.T) {
	_ = newGuest(tagFilterRegistration()) // populates the registry
	g := newGuest(fixtureRegistration())  // fixtureRegistration registers no tags
	resp := invokeHook(t, g, abiv1.Hook_HOOK_DESCRIBE, &abiv1.DescribeRequest{HostAbiVersion: 1})
	dr := &abiv1.DescribeResponse{}
	if err := proto.Unmarshal(resp.GetPayload(), dr); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}
	if got := dr.GetManifest().GetDeclaredTags(); len(got) != 0 {
		t.Errorf("declared_tags = %v, want empty (registry not reset per guest)", got)
	}
}

func TestPoweredBlockRoundTrip(t *testing.T) {
	g := newGuest(tagFilterRegistration())
	resp := invokeHook(t, g, abiv1.Hook_HOOK_RENDER_BLOCK, &abiv1.RenderBlockRequest{
		BlockKey:    "capfx:hero",
		ContentJson: []byte(`{"title":"Welcome"}`),
	})
	if resp.GetError() != nil {
		t.Fatalf("render error: %v", resp.GetError())
	}
	rb := &abiv1.RenderBlockResponse{}
	if err := proto.Unmarshal(resp.GetPayload(), rb); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}
	if rb.GetHtml() != "" {
		t.Errorf("html = %q, want empty (powered)", rb.GetHtml())
	}
	p := rb.GetPowered()
	if p == nil {
		t.Fatal("nil Powered result")
	}
	if p.GetTemplate() != "<h1>{{ title }}</h1>" {
		t.Errorf("template = %q", p.GetTemplate())
	}
	if !strings.Contains(string(p.GetDataJson()), `"title":"Welcome"`) {
		t.Errorf("data_json = %s", p.GetDataJson())
	}
}

func TestRenderTagRoundTrip(t *testing.T) {
	g := newGuest(tagFilterRegistration())
	resp := invokeHook(t, g, abiv1.Hook_HOOK_RENDER_TAG, &abiv1.RenderTagRequest{
		TagName:       "greet",
		ArgsJson:      []byte(`{"who":"sam"}`),
		RenderContext: &abiv1.RenderContext{TemplateKey: "landing"},
	})
	if resp.GetError() != nil {
		t.Fatalf("render tag error: %v", resp.GetError())
	}
	tr := &abiv1.RenderTagResponse{}
	if err := proto.Unmarshal(resp.GetPayload(), tr); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}
	if tr.GetHtml() != "hi sam on landing" || tr.GetError() != "" {
		t.Errorf("html=%q error=%q", tr.GetHtml(), tr.GetError())
	}
}

func TestRenderTagFnErrorSurfacesInResponse(t *testing.T) {
	g := newGuest(tagFilterRegistration())
	resp := invokeHook(t, g, abiv1.Hook_HOOK_RENDER_TAG, &abiv1.RenderTagRequest{
		TagName: "greet", ArgsJson: []byte(`{"who":"err"}`),
	})
	if resp.GetError() != nil {
		t.Fatalf("unexpected AbiError: %v", resp.GetError())
	}
	tr := &abiv1.RenderTagResponse{}
	if err := proto.Unmarshal(resp.GetPayload(), tr); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}
	if tr.GetHtml() != "" || !strings.Contains(tr.GetError(), "greet failed") {
		t.Errorf("html=%q error=%q, want error carrying 'greet failed'", tr.GetHtml(), tr.GetError())
	}
}

func TestRenderTagUnknownIsUnimplemented(t *testing.T) {
	g := newGuest(tagFilterRegistration())
	resp := invokeHook(t, g, abiv1.Hook_HOOK_RENDER_TAG, &abiv1.RenderTagRequest{TagName: "nope"})
	if resp.GetError().GetCode() != abiv1.AbiErrorCode_ABI_ERROR_CODE_UNIMPLEMENTED {
		t.Fatalf("error = %v, want UNIMPLEMENTED", resp.GetError())
	}
}

func TestRenderTagPanicRecoversAndStaysCallable(t *testing.T) {
	g := newGuest(tagFilterRegistration())
	resp := invokeHook(t, g, abiv1.Hook_HOOK_RENDER_TAG, &abiv1.RenderTagRequest{
		TagName: "greet", ArgsJson: []byte(`{"who":"boom"}`),
	})
	if resp.GetError().GetCode() != abiv1.AbiErrorCode_ABI_ERROR_CODE_INTERNAL {
		t.Fatalf("error = %v, want INTERNAL", resp.GetError())
	}
	if !strings.Contains(resp.GetError().GetMessage(), "tag kaboom") {
		t.Errorf("message = %q, want panic value", resp.GetError().GetMessage())
	}
	// Guest stays callable after a recovered tag panic.
	resp2 := invokeHook(t, g, abiv1.Hook_HOOK_RENDER_TAG, &abiv1.RenderTagRequest{
		TagName: "greet", ArgsJson: []byte(`{"who":"again"}`),
	})
	if resp2.GetError() != nil {
		t.Fatalf("post-panic tag failed: %v", resp2.GetError())
	}
}

func TestApplyFilterRoundTrip(t *testing.T) {
	g := newGuest(tagFilterRegistration())
	resp := invokeHook(t, g, abiv1.Hook_HOOK_APPLY_FILTER, &abiv1.ApplyFilterRequest{
		FilterName: "upper", Input: "hello",
	})
	if resp.GetError() != nil {
		t.Fatalf("apply filter error: %v", resp.GetError())
	}
	fr := &abiv1.ApplyFilterResponse{}
	if err := proto.Unmarshal(resp.GetPayload(), fr); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}
	if fr.GetOutput() != "HELLO" || fr.GetError() != "" {
		t.Errorf("output=%q error=%q", fr.GetOutput(), fr.GetError())
	}
}

func TestApplyFilterFnErrorSurfacesInResponse(t *testing.T) {
	g := newGuest(tagFilterRegistration())
	resp := invokeHook(t, g, abiv1.Hook_HOOK_APPLY_FILTER, &abiv1.ApplyFilterRequest{
		FilterName: "upper", Input: "err",
	})
	if resp.GetError() != nil {
		t.Fatalf("unexpected AbiError: %v", resp.GetError())
	}
	fr := &abiv1.ApplyFilterResponse{}
	if err := proto.Unmarshal(resp.GetPayload(), fr); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}
	if fr.GetOutput() != "" || !strings.Contains(fr.GetError(), "upper failed") {
		t.Errorf("output=%q error=%q", fr.GetOutput(), fr.GetError())
	}
}

func TestApplyFilterUnknownIsUnimplemented(t *testing.T) {
	g := newGuest(tagFilterRegistration())
	resp := invokeHook(t, g, abiv1.Hook_HOOK_APPLY_FILTER, &abiv1.ApplyFilterRequest{FilterName: "nope"})
	if resp.GetError().GetCode() != abiv1.AbiErrorCode_ABI_ERROR_CODE_UNIMPLEMENTED {
		t.Fatalf("error = %v, want UNIMPLEMENTED", resp.GetError())
	}
}