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

package interaction

import (
	"strconv"
	"strings"
	"unicode"

	"git.stormux.org/storm/fenrir/internal/i18n"
)

// 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 (c Control) grid_matches() []int {
	var matches []int
	prefix := strings.ToLower(c.Text)
	for index, choice := range c.Choices {
		if strings.HasPrefix(strings.ToLower(choice_label(choice)), prefix) {
			matches = append(matches, index)
		}
	}
	return matches
}

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

func (s *Session) describe_grid(c Control) string {
	matches := c.grid_matches()
	for position, index := range matches {
		if index == c.Selected {
			label := choice_label(c.Choices[index])
			row, column := strconv.Itoa(position/c.Columns+1), strconv.Itoa(position%c.Columns+1)
			item, total := strconv.Itoa(position+1), strconv.Itoa(len(matches))
			switch {
			case s.announceGridCoordinates && s.announceItemPosition:
				return i18n.Format("{0}. row {1}, column {2}. {3} of {4}", label, row, column, item, total)
			case s.announceGridCoordinates:
				return i18n.Format("{0}. row {1}, column {2}", label, row, column)
			case s.announceItemPosition:
				return i18n.Format("{0}. {1} of {2}", label, item, total)
			default:
				return label
			}
		}
	}
	return i18n.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 {
			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)
		c.filter_grid()
		query := i18n.T("Search cleared")
		if c.Text != "" {
			query = i18n.Format("Search {0}", c.Text)
		}
		return Result{Speech: query + ". " + s.describe_grid(*c)}
	}
	matches := c.grid_matches()
	if len(matches) == 0 {
		return Result{Speech: i18n.T("No matches")}
	}
	position := 0
	for current, index := range matches {
		if index == c.Selected {
			position = current
			break
		}
	}
	switch key.Name {
	case "left":
		position = max(0, position-1)
	case "right":
		position = min(len(matches)-1, position+1)
	case "up":
		if position >= c.Columns {
			position -= c.Columns
		}
	case "down":
		if position/c.Columns < (len(matches)-1)/c.Columns {
			position = min(len(matches)-1, position+c.Columns)
		}
	case "home":
		position = 0
	case "end":
		position = len(matches) - 1
	case "enter":
		return Result{Action: c.Action}
	case "delete":
		if key.Repeat {
			return Result{}
		}
		return Result{Action: c.DeleteAction}
	default:
		return Result{}
	}
	c.Selected = matches[position]
	return Result{Speech: s.describe_grid(*c)}
}