package runner

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

// `project_db` is OPTIONAL to the engine, which defaults to `<book_id>.db` beside the file — and the
// operator's own template carries no such key. Refusing here read the bank as missing on every
// deployment that used the template as written.
//
// Mutation caught: requiring the key.
func TestTheProjectDatabaseDefaultsTheWayTheEngineDefaultsIt(t *testing.T) {
	dir := t.TempDir()
	if err := os.WriteFile(filepath.Join(dir, ConfigFile), []byte("book_id: sample-zh\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	got, err := projectDB(dir)
	if err != nil {
		t.Fatalf("a configuration without project_db: %v", err)
	}
	if want := filepath.Join(dir, "sample-zh.db"); got != want {
		t.Errorf("project database %q, want %q", got, want)
	}
	// Declared explicitly, it still wins.
	if err := os.WriteFile(filepath.Join(dir, ConfigFile),
		[]byte("book_id: sample-zh\nproject_db: other.db\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	if got, err = projectDB(dir); err != nil || got != filepath.Join(dir, "other.db") {
		t.Errorf("a declared project_db answered %q (%v)", got, err)
	}
	// Neither key: there is nothing to derive from, and that IS a failure.
	if err := os.WriteFile(filepath.Join(dir, ConfigFile), []byte("title: x\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	if _, err := projectDB(dir); err == nil {
		t.Error("a configuration naming neither key was accepted")
	}
}