package promptkit_test

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

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

type sourceDocument struct {
	First  string `yaml:"first"`
	Second string `yaml:"second"`
}

func TestCollectionInputValidatesWithoutReadingSource(t *testing.T) {
	input, err := promptkit.CollectionInput("docs", configkit.File(filepath.Join(t.TempDir(), "not-read.yaml")))
	if err != nil {
		t.Fatal(err)
	}
	if input.Destination.String() != "/collections/docs" || !input.Imports {
		t.Fatalf("collection input = %+v, want destination /collections/docs with imports enabled", input)
	}
	for _, namespace := range []string{"", " ", "docs/api"} {
		if _, err := promptkit.CollectionInput(namespace, configkit.NoSource()); !errors.Is(err, promptkit.ErrInvalidConfig) {
			t.Errorf("namespace %q error = %v, want ErrInvalidConfig", namespace, err)
		}
	}
}

func TestCollectionInputLoadsNativeImportsAndLaterOverride(t *testing.T) {
	directory := t.TempDir()
	mainPath := filepath.Join(directory, "collection.yaml")
	defaultsPath := filepath.Join(directory, "defaults.yaml")
	if err := os.WriteFile(mainPath, []byte("configkit:\n  imports:\n    - path: defaults.yaml\n"), 0o600); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(defaultsPath, []byte("prompts:\n  greeting:\n    version: imported\n    messages:\n      - role: user\n        content: Hello\n    output:\n      format: text\n      validation_mode: none\n"), 0o600); err != nil {
		t.Fatal(err)
	}
	input, err := promptkit.CollectionInput("docs", configkit.File(mainPath))
	if err != nil {
		t.Fatal(err)
	}
	engine, err := promptkit.NewEngine(promptkit.Config{Sources: promptkit.ConfigurationSources{
		Underlays: []configkit.Underlay{{Inputs: []configkit.Input{input}}},
		Main: &configkit.Input{
			Source:      configkit.Mapping("later collection override", map[string]any{"prompts": map[string]any{"greeting": map[string]any{"version": "overridden"}}}),
			Destination: configkit.Keys("collections", "docs"),
		},
	}})
	if err != nil {
		t.Fatalf("construct engine with native collection import: %v", err)
	}
	inspection, err := engine.InspectPrompt(context.Background(), "docs/greeting")
	if err != nil || inspection.PromptVersion == nil || *inspection.PromptVersion != "overridden" {
		t.Fatalf("inspect imported and overlaid prompt = (%+v, %v)", inspection, err)
	}
}

func TestCollectionInputLoadsEmbeddedImportsAndLaterOverride(t *testing.T) {
	files := fstest.MapFS{
		"collection.yaml": {Data: []byte("configkit:\n  imports:\n    - path: defaults.yaml\n")},
		"defaults.yaml":   {Data: []byte("prompts:\n  greeting:\n    version: imported\n    messages:\n      - role: user\n        content: Hello\n    output:\n      format: text\n      validation_mode: none\n")},
	}
	filesystem := configkit.NewFilesystem("embedded collection", files)
	input, err := promptkit.CollectionInput("docs", filesystem.File("collection.yaml"))
	if err != nil {
		t.Fatal(err)
	}
	input.Filesystem = &configkit.FilesystemContext{FS: &filesystem, Root: "."}
	engine, err := promptkit.NewEngine(promptkit.Config{Sources: promptkit.ConfigurationSources{
		Underlays: []configkit.Underlay{{Inputs: []configkit.Input{input}}},
		Main: &configkit.Input{
			Source:      configkit.Mapping("later collection override", map[string]any{"prompts": map[string]any{"greeting": map[string]any{"version": "overridden"}}}),
			Destination: configkit.Keys("collections", "docs"),
		},
	}})
	if err != nil {
		t.Fatalf("construct engine with embedded collection import: %v", err)
	}
	inspection, err := engine.InspectPrompt(context.Background(), "docs/greeting")
	if err != nil || inspection.PromptVersion == nil || *inspection.PromptVersion != "overridden" {
		t.Fatalf("inspect imported and overlaid prompt = (%+v, %v)", inspection, err)
	}
}

func TestDirectoryInputsSelectsSortedFilesWithRootContext(t *testing.T) {
	root := t.TempDir()
	if err := os.Mkdir(filepath.Join(root, "nested"), 0o755); err != nil {
		t.Fatal(err)
	}
	for name, data := range map[string]string{
		"a.yaml": "first: one\n", "nested/b.yml": "second: two\n", "nested/body.md": "message",
	} {
		if err := os.WriteFile(filepath.Join(root, name), []byte(data), 0o600); err != nil {
			t.Fatal(err)
		}
	}
	inputs, err := promptkit.DirectoryInputs(root)
	if err != nil || len(inputs) != 2 || inputs[0].Imports || inputs[1].Imports {
		t.Fatalf("directory inputs: %+v, %v", inputs, err)
	}
	assertSourceInputs(t, inputs, "message")
	if _, err := promptkit.DirectoryInputs(filepath.Join(root, "missing")); err == nil {
		t.Fatal("missing selected directory succeeded")
	}
	if empty, err := promptkit.DirectoryInputs(t.TempDir()); err != nil || len(empty) != 0 {
		t.Fatalf("empty directory: %+v, %v", empty, err)
	}
}

func TestFilesystemInputsSelectsEmbeddedFilesWithRootContext(t *testing.T) {
	files := fstest.MapFS{
		"settings/a.yaml":         {Data: []byte("first: one\n")},
		"settings/nested/b.yml":   {Data: []byte("second: two\n")},
		"settings/nested/body.md": {Data: []byte("message")},
	}
	inputs, err := promptkit.FilesystemInputs("embedded", files, "settings")
	if err != nil || len(inputs) != 2 || inputs[0].Imports || inputs[1].Imports {
		t.Fatalf("filesystem inputs: %+v, %v", inputs, err)
	}
	assertSourceInputs(t, inputs, "message")
	if _, err := promptkit.FilesystemInputs("embedded", files, "missing"); err == nil {
		t.Fatal("missing selected root succeeded")
	}
}

func assertSourceInputs(t *testing.T, inputs []configkit.Input, expected string) {
	t.Helper()
	result, err := configkit.LoadLayered(configkit.Input{Source: configkit.NoSource()}, configkit.LayeredOptions[sourceDocument]{
		Underlays: []configkit.Underlay{{Inputs: inputs}},
	})
	if err != nil {
		t.Fatal(err)
	}
	if result.Config.First != "one" || result.Config.Second != "two" {
		t.Fatalf("configuration files did not compose: %+v", result.Config)
	}
	field, found := result.Metadata().Lookup(configkit.Keys("second"))
	if !found || len(field.Origin.Locations) != 1 {
		t.Fatalf("missing second-field origin: %+v", field)
	}
	context, found := result.SourceContext(field.Origin.Locations[0].SourceID)
	if !found || context.BaseDir != "nested" {
		t.Fatalf("unexpected rooted source context: %+v", context)
	}
	data, err := fs.ReadFile(context.FS, "nested/body.md")
	if err != nil || string(data) != expected {
		t.Fatalf("rooted resource read: %q, %v", data, err)
	}
}