// Cthulhu screen reader.
// Copyright (c) 2026 Storm Dragon
// Authors: Storm Dragon, Angus Kola
//
// 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 presentation

import (
	"fmt"
	"math"

	"git.stormux.org/storm/cthulhu/internal/atspi"
)

// ComboBoxSelectionText presents the current choice without repeating the
// control's label or role. Native combo snapshots prefer selected-child text.
func ComboBoxSelectionText(snapshot atspi.Snapshot) string {
	if value := controlValue(snapshot); value != "" {
		return value
	}
	if snapshot.Text != "" {
		return snapshot.Text
	}
	return snapshot.Name
}

func controlValue(snapshot atspi.Snapshot) string {
	switch snapshot.Role {
	case "combo box":
		if snapshot.ValueText != "" {
			return snapshot.ValueText
		}
		return snapshot.Description
	case "spin button":
		if snapshot.Text != "" {
			return snapshot.Text
		}
		if snapshot.ValueText != "" {
			return snapshot.ValueText
		}
		if !snapshot.ValueKnown {
			return snapshot.Text
		}
	case "dial", "progress bar", "scroll bar", "slider", "split pane":
	default:
		return ""
	}
	if snapshot.ValueText != "" {
		return snapshot.ValueText
	}
	if !snapshot.ValueKnown || math.IsNaN(snapshot.CurrentValue) || math.IsInf(snapshot.CurrentValue, 0) {
		return ""
	}
	if snapshot.Role != "progress bar" {
		// Python's textForValue formats the actual value using the provider's
		// minimum increment, rather than normalizing controls to percentages.
		increment := snapshot.MinimumIncrement
		if increment < 0 || math.IsNaN(increment) || math.IsInf(increment, 0) {
			return ""
		}
		places := 0
		if increment > 0 {
			places = int(math.Ceil(math.Max(0, -math.Log10(increment))))
		} else if math.Abs(snapshot.CurrentValue) < 1 {
			places = 1
		}
		return fmt.Sprintf("%.*f", places, snapshot.CurrentValue)
	}
	if snapshot.MaximumValue == snapshot.MinimumValue {
		return ""
	}
	percentage := math.Round((snapshot.CurrentValue - snapshot.MinimumValue) /
		(snapshot.MaximumValue - snapshot.MinimumValue) * 100)
	return fmt.Sprintf("%.0f percent", percentage)
}

func controlStates(snapshot atspi.Snapshot) []string {
	var states []string
	switch snapshot.ControlRole() {
	case "check box", "check menu item":
		switch {
		case snapshot.Indeterminate:
			states = append(states, "partially checked")
		case snapshot.Checked:
			states = append(states, "checked")
		default:
			states = append(states, "not checked")
		}
	case "radio button", "radio menu item":
		if snapshot.Checked {
			states = append(states, "selected")
		} else {
			states = append(states, "not selected")
		}
	case "switch":
		if snapshot.Checked {
			states = append(states, "on")
		} else {
			states = append(states, "off")
		}
	case "toggle button":
		if snapshot.Checked {
			states = append(states, "pressed")
		} else {
			states = append(states, "not pressed")
		}
	}
	if snapshot.Expandable {
		if snapshot.Expanded {
			states = append(states, "expanded")
		} else {
			states = append(states, "collapsed")
		}
	}
	if snapshot.Selected && presentsSelectedState(snapshot.Role) {
		states = append(states, "selected")
	}
	if snapshot.Multiselectable {
		states = append(states, "multi-select")
	}
	if snapshot.ReadOnly {
		states = append(states, "read only")
	}
	if snapshot.Required {
		states = append(states, "required")
	}
	if snapshot.Invalid {
		states = append(states, "invalid entry")
	}
	if snapshot.SensitiveKnown && !snapshot.Sensitive {
		states = append(states, "grayed")
	}
	return states
}

func presentsSelectedState(role string) bool {
	switch role {
	case "icon", "list item", "tree item":
		return true
	default:
		return false
	}
}

func stateChangeText(snapshot atspi.Snapshot, eventType string) string {
	switch eventType {
	case "object:state-changed:checked", "object:state-changed:indeterminate", "object:state-changed:pressed":
		for _, state := range controlStates(snapshot) {
			switch state {
			case "partially checked", "checked", "not checked", "selected", "not selected", "on", "off", "pressed", "not pressed":
				return state
			}
		}
	case "object:state-changed:expanded":
		if snapshot.Expanded {
			return "expanded"
		}
		return "collapsed"
	case "object:state-changed:invalid-entry":
		if snapshot.Invalid {
			return "invalid entry"
		}
	case "object:state-changed:read-only":
		if snapshot.ReadOnly {
			return "read only"
		}
		return "editable"
	case "object:state-changed:required":
		if snapshot.Required {
			return "required"
		}
	case "object:state-changed:selected":
		if snapshot.Role == "table cell" {
			if snapshot.Selected {
				return "selected"
			}
			return ""
		}
		if presentsSelectedState(snapshot.Role) {
			if snapshot.Selected {
				return "selected"
			}
			return "not selected"
		}
	case "object:state-changed:sensitive":
		if snapshot.SensitiveKnown && !snapshot.Sensitive {
			return "grayed"
		}
	}
	return ""
}