package llm

import (
	"context"
	"errors"
	"io/fs"
	"os"
	"path"
	"path/filepath"
	"testing"
	"testing/fstest"

	"gitea.maximumdirect.net/eric/audita/v3/internal/core/config"
	"gitea.maximumdirect.net/eric/audita/v3/internal/prompts"
	ck "go.maximumdirect.net/configkit"
)

func copyEmbeddedPromptFilesystem(t *testing.T) fstest.MapFS {
	t.Helper()
	source := prompts.Filesystem()
	files := make(fstest.MapFS)
	err := fs.WalkDir(source, prompts.AssetRoot, func(name string, entry fs.DirEntry, err error) error {
		if err != nil || entry.IsDir() {
			return err
		}
		data, err := fs.ReadFile(source, name)
		if err != nil {
			return err
		}
		files[name] = &fstest.MapFile{Data: data}
		return nil
	})
	if err != nil {
		t.Fatal(err)
	}
	return files
}

func TestRuntimeClassifiesEmbeddedAssetsAndHonorsCancellation(t *testing.T) {
	loaded, err := config.Load(ck.Input{Source: ck.NoSource()}, "")
	if err != nil {
		t.Fatal(err)
	}
	_, err = newRuntimeWithPromptFS(context.Background(), loaded, nil, fstest.MapFS{})
	if err == nil || !IsAssetError(err) || !errors.Is(err, fs.ErrNotExist) {
		t.Fatalf("embedded discovery error was not preserved as an asset error: %v", err)
	}
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	_, err = newRuntimeWithPromptFS(ctx, loaded, nil, fstest.MapFS{})
	if !errors.Is(err, context.Canceled) || IsAssetError(err) {
		t.Fatalf("caller cancellation classification: %v", err)
	}
}

func TestBrokenEmbeddedPromptFailsEmbeddedOnlyConstruction(t *testing.T) {
	promptFS := copyEmbeddedPromptFilesystem(t)
	assetPath := path.Join(prompts.AssetRoot, "modules.grammar.proposal.yaml")
	promptFS[assetPath] = &fstest.MapFile{Data: []byte("collections:\n  audita:\n    prompts:\n      - id: modules.grammar.proposal\n        messages: []\n")}
	loaded, err := config.Load(ck.Input{Source: ck.NoSource()}, "")
	if err != nil {
		t.Fatal(err)
	}
	_, err = newRuntimeWithPromptFS(context.Background(), loaded, nil, promptFS)
	if err == nil || !IsAssetError(err) {
		t.Fatalf("broken embedded prompt was not classified as an asset error: %v", err)
	}
}

func TestOperatorPromptCanRepairInvalidEmbeddedPrompt(t *testing.T) {
	promptFS := copyEmbeddedPromptFilesystem(t)
	assetPath := path.Join(prompts.AssetRoot, "modules.grammar.proposal.yaml")
	promptFS[assetPath] = &fstest.MapFile{Data: []byte("collections:\n  audita:\n    prompts:\n      - id: modules.grammar.proposal\n        messages: []\n")}
	dir := t.TempDir()
	for name, content := range map[string]string{
		"config.yml":  "version: 3\n",
		"prompts.yml": "collections:\n  audita:\n    prompts:\n      - id: modules.grammar.proposal\n        messages:\n          - role: user\n            content: operator message\n        output:\n          format: text\n          validation_mode: none\n",
	} {
		if err := os.WriteFile(filepath.Join(dir, name), []byte(content), 0600); err != nil {
			t.Fatal(err)
		}
	}
	loaded, err := config.Load(ck.Input{Source: ck.File(filepath.Join(dir, "config.yml"))}, "")
	if err != nil {
		t.Fatal(err)
	}
	runtime, err := newRuntimeWithPromptFS(context.Background(), loaded, nil, promptFS)
	if err != nil {
		t.Fatalf("valid final configuration rejected: %v", err)
	}
	if runtime.Engine == nil {
		t.Fatal("runtime engine was not retained")
	}
}