package configkit_test

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

	configkit "gitea.maximumdirect.net/eric/ConfigKit"
)

func TestFacadeNativeDiscoveryPreservesAliasIdentity(t *testing.T) {
	root := t.TempDir()
	for name, contents := range map[string]string{
		"data/item.yml":        "configkit:\n  imports:\n    - path: helper.yml\nvalue: item\n",
		"data/helper.yml":      "owner: target\nresource: resource.txt\n",
		"aliases/helper.yml":   "owner: alias\nresource: resource.txt\n",
		"data/resource.txt":    "target resource",
		"aliases/resource.txt": "alias resource",
	} {
		filename := filepath.Join(root, filepath.FromSlash(name))
		if err := os.MkdirAll(filepath.Dir(filename), 0o700); err != nil {
			t.Fatal(err)
		}
		if err := os.WriteFile(filename, []byte(contents), 0o600); err != nil {
			t.Fatal(err)
		}
	}
	for name, target := range map[string]string{"aliases/item.yml": "../data/item.yml", "linked": "data"} {
		if err := os.Symlink(target, filepath.Join(root, filepath.FromSlash(name))); err != nil {
			t.Skipf("symlinks unavailable: %v", err)
		}
	}
	filesystem := configkit.NewFilesystem("aliases", os.DirFS(root))
	type configuration struct {
		Value    string `yaml:"value"`
		Owner    string `yaml:"owner"`
		Resource string `yaml:"resource"`
	}
	for _, test := range []struct {
		name, declaration, item, helper, owner, resource string
	}{
		{"file/path", "path: aliases/item.yml", "aliases/item.yml", "aliases/helper.yml", "alias", "alias resource"},
		{"file/dir", "dir: aliases\n      pattern: item.yml", "aliases/item.yml", "aliases/helper.yml", "alias", "alias resource"},
		{"file/glob", "glob: 'aliases/ite*.yml'", "aliases/item.yml", "aliases/helper.yml", "alias", "alias resource"},
		{"directory/path", "path: linked/item.yml", "linked/item.yml", "linked/helper.yml", "target", "target resource"},
		{"directory/dir", "dir: linked\n      pattern: item.yml", "linked/item.yml", "linked/helper.yml", "target", "target resource"},
		{"directory/glob", "glob: 'lin*/ite*.yml'", "linked/item.yml", "linked/helper.yml", "target", "target resource"},
	} {
		t.Run(test.name, func(t *testing.T) {
			result, err := configkit.Load(configkit.Bytes("main", []byte("configkit:\n  imports:\n    - "+test.declaration+"\n")), configkit.Options[configuration]{
				Imports: true, Filesystem: &configkit.FilesystemContext{FS: &filesystem, Root: ".", BaseDir: "."},
			})
			if err != nil {
				t.Fatal(err)
			}
			if result.Config.Owner != test.owner || result.Config.Value != "item" {
				t.Fatalf("configuration = %#v", result.Config)
			}
			sources := result.Sources()
			if len(sources) != 3 || sources[1].Path != test.item || sources[2].Path != test.helper {
				t.Fatalf("source identities = %#v", sources)
			}
			for field, source := range map[string]configkit.SourceInfo{"value": sources[1], "resource": sources[2]} {
				info, ok := result.Metadata().Lookup(configkit.Keys(field))
				if !ok || len(info.Origin.Locations) != 1 || info.Origin.Locations[0].SourceID != source.ID {
					t.Fatalf("%s origin = %#v", field, info)
				}
				context, ok := result.SourceContext(source.ID)
				if !ok || context.BaseDir != path.Dir(source.Path) {
					t.Fatalf("%s context = %#v", field, context)
				}
				contents, err := fs.ReadFile(context.FS, path.Join(context.BaseDir, result.Config.Resource))
				if err != nil || string(contents) != test.resource {
					t.Fatalf("%s resource = %q, %v", field, contents, err)
				}
			}
		})
	}
	// The same native path is still a repeat when separately included. An alias
	// to a leaf file remains a different native namespace path, as for path imports.
	for _, selector := range []string{"path: aliases/item.yml", "dir: aliases\n      pattern: item.yml", "glob: 'aliases/ite*.yml'"} {
		_, err := configkit.Load(configkit.Bytes("main", []byte("configkit:\n  imports:\n    - "+selector+"\n    - path: aliases/item.yml\n")), configkit.Options[configuration]{
			Imports: true, Filesystem: &configkit.FilesystemContext{FS: &filesystem, Root: ".", BaseDir: "."},
		})
		var loadError *configkit.LoadError
		if !errors.As(err, &loadError) || len(loadError.Diagnostics()) != 1 || loadError.Diagnostics()[0].Code != configkit.CodeImportRepeated {
			t.Fatalf("repeated source: %v", err)
		}
		_, err = configkit.Load(configkit.Bytes("main", []byte("configkit:\n  imports:\n    - "+selector+"\n    - path: data/item.yml\n")), configkit.Options[configuration]{
			Imports: true, Filesystem: &configkit.FilesystemContext{FS: &filesystem, Root: ".", BaseDir: "."},
		})
		if !errors.As(err, &loadError) || len(loadError.Diagnostics()) == 0 || loadError.Diagnostics()[0].Code != configkit.CodeComposeConflict {
			t.Fatalf("distinct native alias paths should reach composition: %v", err)
		}
	}
}