// Copyright (c) 2026 Storm Dragon
// SPDX-License-Identifier: GPL-3.0-or-later

package atspi

/*
#cgo pkg-config: atspi-2 glib-2.0 gobject-2.0
#include <atspi/atspi.h>
*/
import "C"

import (
	"context"
	"errors"
	"strings"
	"time"
)

// ReadFocusedLine reads only the line containing the current native caret.
func (adapter *Adapter) ReadFocusedLine(ctx context.Context, focus ObjectID) (DocumentContent, error) {
	result, err := adapter.documentOperation(ctx, treeCaptureRequest{reviewFocus: focus, readFocusedLine: true})
	return result.content, err
}

// ReadFocusedSnapshot captures presentation and privacy metadata together on
// the GLib owner. It neither moves focus nor changes the native caret.
func (adapter *Adapter) ReadFocusedSnapshot(ctx context.Context, focus ObjectID) (DocumentContent, error) {
	result, err := adapter.documentOperation(ctx, treeCaptureRequest{reviewFocus: focus, readFocusedSnapshot: true})
	return result.content, err
}

func (adapter *Adapter) read_native_focused_snapshot(ctx context.Context, focus ObjectID) (DocumentContent, error) {
	if err := ctx.Err(); err != nil {
		return DocumentContent{}, err
	}
	if !adapter.nativeFocusIs(focus) {
		return DocumentContent{}, ErrStaleObject
	}
	source := adapter.nativeFocus[len(adapter.nativeFocus)-1].source
	C.atspi_accessible_clear_cache_single(source)
	snapshot := snapshotFromNativeWithCaret(source, true, false, false, false)
	return DocumentContent{Snapshot: snapshot, SourceContext: native_focused_line_context(ctx, source)}, ctx.Err()
}

func (adapter *Adapter) read_native_focused_line(ctx context.Context, focus ObjectID) (content DocumentContent, err error) {
	if err := ctx.Err(); err != nil {
		return DocumentContent{}, err
	}
	if !adapter.nativeFocusIs(focus) {
		return DocumentContent{}, ErrStaleObject
	}
	source := adapter.nativeFocus[len(adapter.nativeFocus)-1].source
	C.atspi_accessible_clear_cache_single(source)
	snapshot := snapshotFromNativeWithCaret(source, false, false, false, false)
	if snapshot.Role == "password text" {
		return DocumentContent{}, ErrNoDocumentCaret
	}
	content = DocumentContent{Snapshot: snapshot, Text: snapshot.Name}
	defer func() {
		if err == nil {
			content.SourceContext = native_focused_line_context(ctx, source)
		}
	}()
	text := C.atspi_accessible_get_text_iface(source)
	if text == nil {
		return content, ctx.Err()
	}
	defer C.g_object_unref(C.gpointer(text))
	reader := nativeReviewText{text: text, terminal: snapshot.Role == "terminal"}
	count, err := reader.count(ctx)
	if err != nil {
		return DocumentContent{}, err
	}
	content.Text = ""
	if count == 0 {
		return content, ctx.Err()
	}
	var nativeErr *C.GError
	offset := int(C.atspi_text_get_caret_offset(text, &nativeErr))
	if nativeErr != nil {
		err := nativeError("read current line caret", nativeErr)
		C.g_error_free(nativeErr)
		return DocumentContent{}, err
	}
	// A text object without a caret reads from its first line, as NVDA does.
	offset = min(max(0, offset), count)
	if offset == count {
		last := C.atspi_text_get_text(text, C.gint(count-1), C.gint(count), &nativeErr)
		if last != nil {
			defer C.g_free(C.gpointer(last))
		}
		if nativeErr != nil {
			err := nativeError("read current line end", nativeErr)
			C.g_error_free(nativeErr)
			return DocumentContent{}, err
		}
		// A trailing newline puts the caret on an empty final line.
		if strings.HasSuffix(C.GoString(last), "\n") {
			content.Start, content.End = count, count
			return content, ctx.Err()
		}
		offset--
	}
	line, err := reader.line(ctx, offset)
	if err != nil {
		return DocumentContent{}, err
	}
	if line.Start < 0 || line.Start > offset || line.End <= offset || line.End > count {
		return DocumentContent{}, errors.New("read current line: invalid text range")
	}
	content.Start, content.End, content.Text, content.RawText = line.Start, line.End, line.Text, line.Text
	return content, ctx.Err()
}

// Privacy capture is separate from presentation context: include every parent,
// even unnamed containers and parents outside the window. Keep it on the GLib
// owner and bound the walk without scanning children or retaining native refs.
// Failed/truncated capture must not turn a successful local read into an error.
func native_focused_line_context(ctx context.Context, source *C.AtspiAccessible) []Snapshot {
	deadline, cancel := context.WithTimeout(ctx, 100*time.Millisecond)
	defer cancel()
	current := (*C.AtspiAccessible)(C.g_object_ref(C.gpointer(source)))
	defer func() {
		if current != nil {
			C.g_object_unref(C.gpointer(current))
		}
	}()
	var result []Snapshot
	seen := make(map[ObjectID]bool)
	for current != nil && len(result) < 64 && deadline.Err() == nil {
		C.atspi_accessible_clear_cache_single(current)
		id := nativeObjectID(current)
		if !id.Valid() || seen[id] {
			return nil
		}
		seen[id] = true
		var nativeErr *C.GError
		roleName := C.atspi_accessible_get_role_name(current, &nativeErr)
		role := C.GoString(roleName)
		C.g_free(C.gpointer(roleName))
		if nativeErr != nil {
			C.g_error_free(nativeErr)
			return nil
		}
		states := C.atspi_accessible_get_state_set(current)
		if states == nil {
			return nil
		}
		defunct := C.atspi_state_set_contains(states, C.ATSPI_STATE_DEFUNCT) != 0
		C.g_object_unref(C.gpointer(states))
		result = append(result, Snapshot{BusName: id.BusName, Path: id.Path, Role: role, Defunct: defunct})
		if role == "application" {
			if deadline.Err() != nil {
				return nil
			}
			return result
		}
		parent := C.atspi_accessible_get_parent(current, &nativeErr)
		C.g_object_unref(C.gpointer(current))
		current = parent
		if nativeErr != nil {
			C.g_error_free(nativeErr)
			return nil
		}
	}
	return nil
}