// Fenrir console screen reader.
// Copyright (c) 2026 Storm Dragon
// SPDX-License-Identifier: GPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation, either version 3 of the License, or (at your option)
// any later version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
// more details.
//
// You should have received a copy of the GNU General Public License along with
// this program. If not, see <https://www.gnu.org/licenses/gpl-3.0.html>.

package internalui

import (
	"strconv"
	"strings"
	"unicode/utf8"
)

func (s *Session) Open() string { return s.messages.T(s.form.Title) + ". " + s.Describe() }

func (s *Session) describe() string {
	if s.closed {
		return ""
	}
	tab := s.form.Tabs[s.tab]
	if s.focus == -1 {
		return s.messages.Format("{0} tab", s.messages.T(tab.Label))
	}
	control := tab.Controls[s.focus]
	label := s.messages.T(control.Label)
	switch control.Kind {
	case CheckBox:
		state := "unchecked"
		if control.Checked {
			state = "checked"
		}
		return label + " " + s.messages.T(state)
	case Number:
		return label + " " + strconv.FormatFloat(control.Number, 'f', -1, 64)
	case Entry:
		return s.Presentation().Speech
	case List:
		if control.Selected < 0 {
			return label
		}
		return label + " " + s.list_labels(control)[control.Selected]
	case Grid:
		return s.messages.Format("{0} grid. {1}", label, s.describe_grid(control))
	case ComboBox:
		return s.messages.Format("{0} combo box {1}", label, s.describe_choice(control))
	case Button:
		return s.messages.Format("{0} button", label)
	}
	return label
}

func (s *Session) describe_choice(control Control) string {
	choice := control.Choices[control.Selected]
	text := s.choice_label(choice)
	if choice.Unavailable != "" {
		text += ". " + s.messages.T("unavailable") + ": " + choice.Unavailable
	}
	return text
}

func (s *Session) choice_label(choice Choice) string {
	if choice.Literal {
		return choice.Label
	}
	return s.messages.T(choice.Label)
}

func (s *Session) focused_group() string {
	if s.focus < 0 {
		return ""
	}
	return s.form.Tabs[s.tab].Controls[s.focus].Group
}

func (s *Session) describe_focus(previousGroup string) string {
	if group := s.focused_group(); group != "" && group != previousGroup {
		return s.messages.T(group) + ". " + s.Describe()
	}
	return s.Describe()
}

func (s *Session) Describe() string { return s.Presentation().Speech }
func (s *Session) Presentation() Result {
	if s.closed {
		return Result{}
	}
	if s.focus < 0 {
		text := s.messages.Format("{0} tab", s.messages.T(s.form.Tabs[s.tab].Label))
		return Result{Speech: text, Braille: text, Cursor: -1}
	}
	c := s.form.Tabs[s.tab].Controls[s.focus]
	label := s.messages.T(c.Label)
	if c.Kind == Entry {
		template := "{0}, edit: {1}"
		if !s.form.Detailed {
			template = "{0} entry {1}"
		}
		value := c.Text
		if c.Secret {
			template = "{0}, password edit: {1}"
			value = strings.Repeat("*", utf8.RuneCountInString(c.Text))
		}
		text := s.messages.Format(template, label, value)
		marker := s.messages.Format(template, label, "\x00")
		offset := strings.IndexByte(marker, 0)
		cursor := -1
		if offset >= 0 {
			cursor = len([]rune(marker[:offset])) + s.cursor
		}
		if s.cursor != s.anchor {
			n := s.cursor - s.anchor
			if n < 0 {
				n = -n
			}
			text += s.messages.Format(" (selected {0} characters)", strconv.Itoa(n))
		}
		speech := text
		if c.Secret {
			speech = s.messages.Format("{0}, password edit, {1}", label, s.characterCount(utf8.RuneCountInString(c.Text)))
		}
		return Result{Speech: speech, Braille: text, Cursor: cursor}
	}
	text := s.describe()
	speech := text
	if s.form.Detailed {
		switch c.Kind {
		case List:
			if c.Selected >= 0 {
				speech = s.list_labels(c)[c.Selected]
				text = s.messages.Format("{0}: {1}, {2} of {3}", label, speech, strconv.Itoa(c.Selected+1), strconv.Itoa(len(s.list_labels(c))))
			}
		case CheckBox:
			state := "unchecked"
			if c.Checked {
				state = "checked"
			}
			text = label + ", " + s.messages.T(state)
			speech = text
		case Button:
			text = s.messages.Format("{0}, button", label)
			speech = text
		case Grid:
			text = s.describe_grid(c)
			speech = text
		}
	}
	return Result{Speech: speech, Braille: text, Cursor: -1}
}