package compass

import (
	"os"
	"path/filepath"
	"testing"
	"testing/fstest"
)

func TestLoadStringFromAppSection(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "app.yaml")
	if err := os.WriteFile(path, []byte("name: hello-app\n"), 0o644); err != nil {
		t.Fatal(err)
	}

	cfg, err := Load(dir)
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if got := cfg.String("app.name"); got != "hello-app" {
		t.Fatalf("String(app.name) = %q, want hello-app", got)
	}
}

func TestOpenDefaultsEnvToProduction(t *testing.T) {
	dir := writeConfigTree(t, map[string]string{
		"app.yaml": "name: base\ndebug: false\n",
		"env/production/app.yaml": "debug: true\n",
		"env/development/app.yaml": "name: dev\n",
	})
	cfg, err := Open(Options{Dir: dir, Environ: []string{}})
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	if cfg.Environment() != "production" {
		t.Fatalf("Environment = %q, want production", cfg.Environment())
	}
	if got := cfg.String("app.name"); got != "base" {
		t.Fatalf("name = %q, want base", got)
	}
	if !cfg.Bool("app.debug") {
		t.Fatal("production overlay should set app.debug")
	}
}

func TestExplicitEnvWinsOverSUMMER_ENV(t *testing.T) {
	dir := writeConfigTree(t, map[string]string{
		"app.yaml":                 "name: base\n",
		"env/development/app.yaml": "name: from-dev\n",
		"env/staging/app.yaml":     "name: from-staging\n",
	})
	cfg, err := Open(Options{
		Dir:     dir,
		Env:     "staging",
		Environ: []string{"SUMMER_ENV=development"},
	})
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	if cfg.Environment() != "staging" {
		t.Fatalf("Environment = %q, want staging", cfg.Environment())
	}
	if got := cfg.String("app.name"); got != "from-staging" {
		t.Fatalf("name = %q, want from-staging", got)
	}
}

func TestDeepMergeKeepsUntouchedNestedKeys(t *testing.T) {
	dir := writeConfigTree(t, map[string]string{
		"database.yaml": `
host: localhost
port: 5432
pool:
  max: 10
  idle: 2
`,
		"env/development/database.yaml": `
host: dev-db
pool:
  max: 20
`,
	})
	cfg, err := Open(Options{Dir: dir, Env: "development", Environ: []string{}})
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	if got := cfg.String("database.host"); got != "dev-db" {
		t.Fatalf("host = %q, want dev-db", got)
	}
	if got := cfg.Int("database.port"); got != 5432 {
		t.Fatalf("port = %d, want 5432", got)
	}
	if got := cfg.Int("database.pool.max"); got != 20 {
		t.Fatalf("pool.max = %d, want 20", got)
	}
	if got := cfg.Int("database.pool.idle"); got != 2 {
		t.Fatalf("pool.idle = %d, want 2", got)
	}
}

func TestMergePluginConfigAtBarePluginID(t *testing.T) {
	dir := writeConfigTree(t, map[string]string{
		"app.yaml": "name: hello-app\n",
	})
	cfg, err := Open(Options{Dir: dir, Environ: []string{}})
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	fsys := fstest.MapFS{
		"config/config.yaml": {Data: []byte("posts_per_page: 10\nshow_author: true\n")},
	}
	if err := cfg.MergePlugin("golem15.hello", fsys); err != nil {
		t.Fatalf("MergePlugin: %v", err)
	}
	if got := cfg.Int("golem15.hello.posts_per_page"); got != 10 {
		t.Fatalf("posts_per_page = %d, want 10", got)
	}
	if !cfg.Bool("golem15.hello.show_author") {
		t.Fatal("show_author should be true")
	}
	if !cfg.Has("golem15.hello.posts_per_page") {
		t.Fatal("Has(golem15.hello.posts_per_page) = false")
	}
	got, ok := cfg.Lookup("golem15.hello.posts_per_page")
	if !ok {
		t.Fatal("Lookup missing posts_per_page")
	}
	switch v := got.(type) {
	case int:
		if v != 10 {
			t.Fatalf("Lookup = %v, want 10", got)
		}
	case int64:
		if v != 10 {
			t.Fatalf("Lookup = %v, want 10", got)
		}
	case uint64:
		if v != 10 {
			t.Fatalf("Lookup = %v, want 10", got)
		}
	default:
		// YAML may decode as int or the getter path may return the raw value.
		if cfg.Int("golem15.hello.posts_per_page") != 10 {
			t.Fatalf("Lookup type %T value %v", got, got)
		}
	}

	var section struct {
		PostsPerPage int  `koanf:"posts_per_page"`
		ShowAuthor   bool `koanf:"show_author"`
	}
	if err := cfg.LoadSection("golem15.hello", &section); err != nil {
		t.Fatalf("LoadSection: %v", err)
	}
	if section.PostsPerPage != 10 || !section.ShowAuthor {
		t.Fatalf("LoadSection = %+v", section)
	}
}

func TestEnvVarsOverridePluginDefaults(t *testing.T) {
	dir := writeConfigTree(t, map[string]string{
		"app.yaml": "name: hello-app\n",
	})
	cfg, err := Open(Options{
		Dir: dir,
		Environ: []string{
			"SUMMER_GOLEM15__HELLO__POSTS_PER_PAGE=25",
		},
	})
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	fsys := fstest.MapFS{
		"config/config.yaml": {Data: []byte("posts_per_page: 10\n")},
	}
	if err := cfg.MergePlugin("golem15.hello", fsys); err != nil {
		t.Fatalf("MergePlugin: %v", err)
	}
	if got := cfg.Int("golem15.hello.posts_per_page"); got != 25 {
		t.Fatalf("posts_per_page = %d, want 25 (env over plugin default)", got)
	}
}

func TestPriorityRuntimeSetThenPersistThenEnvThenOverlayThenBaseThenPlugin(t *testing.T) {
	dir := writeConfigTree(t, map[string]string{
		"app.yaml": "name: base\n",
		"env/development/app.yaml": "name: overlay\n",
		"env/development/overrides.yaml": "app:\n  name: persisted\n",
	})
	cfg, err := Open(Options{
		Dir:     dir,
		Env:     "development",
		Environ: []string{"SUMMER_APP__NAME=from-env"},
	})
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	if got := cfg.String("app.name"); got != "persisted" {
		t.Fatalf("before Set, name = %q, want persisted", got)
	}
	if err := cfg.Set("app.name", "runtime"); err != nil {
		t.Fatalf("Set: %v", err)
	}
	if got := cfg.String("app.name"); got != "runtime" {
		t.Fatalf("after Set, name = %q, want runtime", got)
	}
}

func TestSortedSectionFilesLoadDeterministically(t *testing.T) {
	dir := writeConfigTree(t, map[string]string{
		"b.yaml": "value: b\n",
		"a.yaml": "value: a\nshared: 1\n",
	})
	cfg, err := Open(Options{Dir: dir, Environ: []string{}})
	if err != nil {
		t.Fatalf("Open: %v", err)
	}
	if got := cfg.String("a.value"); got != "a" {
		t.Fatalf("a.value = %q, want a", got)
	}
	if got := cfg.String("b.value"); got != "b" {
		t.Fatalf("b.value = %q, want b", got)
	}
	if got := cfg.Int("a.shared"); got != 1 {
		t.Fatalf("a.shared = %d, want 1", got)
	}
}

func writeConfigTree(t *testing.T, files map[string]string) string {
	t.Helper()
	dir := t.TempDir()
	for name, body := range files {
		path := filepath.Join(dir, name)
		if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
			t.Fatal(err)
		}
		if err := os.WriteFile(path, []byte(body), 0o644); err != nil {
			t.Fatal(err)
		}
	}
	return dir
}