// Fenrir console screen reader.
// Copyright (c) 2026 Storm Dragon
// SPDX-License-Identifier: GPL-3.0-or-later

package internalui

import (
	gridmodel "git.stormux.org/storm/screenreader-common/internalui/grid"
	"strings"
	"unicode"
	"unicode/utf8"
)

// Grid selections index Choices, even while the visible results are filtered.
// Choice IDs remain opaque to the model and can carry a host-owned value.
func (s *Session) grid_matches(c Control) []int {
	var matches []int
	prefix := strings.ToLower(c.Text)
	for index, choice := range c.Choices {
		if !choice.Disabled && strings.HasPrefix(strings.ToLower(s.choice_label(choice)), prefix) {
			matches = append(matches, index)
		}
	}
	return matches
}

func (s *Session) filter_grid(c *Control) {
	c.Selected = -1
	if matches := s.grid_matches(*c); len(matches) > 0 {
		c.Selected = matches[0]
	}
}

func (s *Session) describe_grid(c Control) string {
	matches := s.grid_matches(c)
	for position, index := range matches {
		if index == c.Selected {
			label := s.choice_label(c.Choices[index])
			return gridmodel.Describe(label, position, len(matches), c.Columns, s.announceGridCoordinates, s.announceItemPosition, s.messages)
		}
	}
	return s.messages.T("No matches")
}

func (s *Session) grid(c *Control, key Key) Result {
	if key.Ctrl && key.Name != "backspace" {
		return Result{}
	}
	if key.Name == "backspace" || (key.Name == "" || key.Name == "space") && key.Text != "" && !key.Ctrl {
		runes := []rune(c.Text)
		if key.Name == "backspace" {
			if key.Ctrl {
				runes = nil
			} else if len(runes) > 0 {
				runes = runes[:len(runes)-1]
			}
		} else {
			if !utf8.ValidString(key.Text) {
				return Result{}
			}
			for _, char := range key.Text {
				if !unicode.IsPrint(char) {
					return Result{}
				}
			}
			if len(runes)+len([]rune(key.Text)) > 4096 {
				return Result{}
			}
			runes = append(runes, []rune(key.Text)...)
		}
		c.Text = string(runes)
		s.filter_grid(c)
		query := s.messages.T("Search cleared")
		if c.Text != "" {
			query = s.messages.Format("Search {0}", c.Text)
		}
		return Result{Speech: query + ". " + s.describe_grid(*c)}
	}
	matches := s.grid_matches(*c)
	if len(matches) == 0 {
		return Result{Speech: s.messages.T("No matches")}
	}
	position := 0
	for current, index := range matches {
		if index == c.Selected {
			position = current
			break
		}
	}
	if key.Name == "enter" {
		return Result{Action: c.Action}
	}
	if key.Name == "delete" {
		if key.Repeat {
			return Result{}
		}
		return Result{Action: c.DeleteAction}
	}
	var handled bool
	position, handled = gridmodel.Move(position, len(matches), c.Columns, key.Name)
	if !handled {
		return Result{}
	}

	c.Selected = matches[position]
	return Result{Speech: s.describe_grid(*c)}
}