package extractor

import "errors"

// ErrNotPromotable is returned when a Document cannot be promoted to an InteractiveBrowser.
// This happens when the Document is not backed by a Playwright page (e.g. a mock or custom implementation).
var ErrNotPromotable = errors.New("document is not promotable to InteractiveBrowser")

// ErrNotDemotable is returned when an InteractiveBrowser cannot be demoted to a Document.
// This happens when the InteractiveBrowser is not backed by a Playwright page.
var ErrNotDemotable = errors.New("interactive browser is not demotable to Document")

// ErrAlreadyDetached is returned when attempting to promote or demote an object that has
// already been transferred. Each Document or InteractiveBrowser can only be promoted/demoted once.
var ErrAlreadyDetached = errors.New("already detached")

// PromoteToInteractive transfers ownership of the underlying Playwright page from a Document
// to a new InteractiveBrowser. After promotion, the Document's Close method becomes a no-op
// (the page is now owned by the returned InteractiveBrowser).
//
// The caller must keep the original Browser alive while the promoted InteractiveBrowser is in use,
// since the Browser still owns the Playwright process and browser instance.
//
// Returns ErrNotPromotable if the Document is not backed by a Playwright page,
// or ErrAlreadyDetached if the Document was already promoted.
func PromoteToInteractive(doc Document) (InteractiveBrowser, error) {
	d, ok := doc.(*document)
	if !ok {
		return nil, ErrNotPromotable
	}

	if d.detached {
		return nil, ErrAlreadyDetached
	}

	d.detached = true

	return &interactiveBrowser{
		pw:      d.pw,
		browser: d.browser,
		ctx:     d.page.Context(),
		page:    d.page,
	}, nil
}

// DemoteToDocument transfers ownership of the underlying Playwright page from an
// InteractiveBrowser back to a new Document. After demotion, the InteractiveBrowser's
// Close method becomes a no-op (the page is now owned by the returned Document).
//
// Returns ErrNotDemotable if the InteractiveBrowser is not backed by a Playwright page,
// or ErrAlreadyDetached if the InteractiveBrowser was already demoted.
func DemoteToDocument(ib InteractiveBrowser) (Document, error) {
	b, ok := ib.(*interactiveBrowser)
	if !ok {
		return nil, ErrNotDemotable
	}

	if b.detached {
		return nil, ErrAlreadyDetached
	}

	b.detached = true

	return newDocument(b.pw, b.browser, b.page)
}