// 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>.

//go:build linux && cgo

package input

/*
#cgo pkg-config: libevdev
#include <libevdev/libevdev.h>
#include <stdlib.h>
*/
import "C"

import (
	"fmt"
	"slices"
	"strconv"
	"strings"
	"unsafe"

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

// ScriptBinding uses Python Fenrir's normalized KEY_* names, including the
// synthetic KEY_SCRIPT, KEY_FENRIR and generic modifier names.
type ScriptBinding struct {
	ID   command.ID
	Keys []string
}

func Key_code(name string) (uint16, bool) {
	name = strings.ToUpper(name)
	aliases := map[string]string{"KEY_CTRL": "KEY_LEFTCTRL", "KEY_SHIFT": "KEY_LEFTSHIFT", "KEY_ALT": "KEY_LEFTALT", "KEY_META": "KEY_LEFTMETA"}
	if alias := aliases[name]; alias != "" {
		name = alias
	}
	text := C.CString(name)
	defer C.free(unsafe.Pointer(text))
	code := int(C.libevdev_event_code_from_name(C.EV_KEY, text))
	return uint16(code), code >= 0 && code <= int(C.KEY_MAX)
}

func Valid_script_key(name string) bool {
	if name == "KEY_SCRIPT" || name == "KEY_FENRIR" {
		return true
	}
	_, ok := Key_code(name)
	return ok
}

// Key_name retains the physical left/right/keypad identity for tutorial input.
func Key_name(code uint16) string {
	name := C.libevdev_event_code_get_name(C.EV_KEY, C.uint(code))
	if name == nil {
		return strconv.Itoa(int(code))
	}
	return C.GoString(name)
}

func Script_chord(keys []string) string {
	keys = slices.Clone(keys)
	slices.Sort(keys)
	return strings.Join(keys, ",")
}

func (r *Router) Configure_scripts(keys []string, bindings []ScriptBinding) error {
	scriptKeys, err := Modifier_codes(keys)
	if err != nil {
		return err
	}
	for code := range scriptKeys {
		if r.reader_modifier(code, false) {
			return fmt.Errorf("%s cannot be both a Fenrir key and a script key", Key_name(code))
		}
	}
	scriptBindings := make(map[string]command.ID)
	for _, binding := range bindings {
		if binding.ID == "" {
			return fmt.Errorf("script binding has no command")
		}
		for _, name := range binding.Keys {
			if !Valid_script_key(name) {
				return fmt.Errorf("invalid script shortcut %q", name)
			}
		}
		chord := Script_chord(binding.Keys)
		if _, exists := scriptBindings[chord]; exists {
			return fmt.Errorf("duplicate script shortcut %s", chord)
		}
		scriptBindings[chord] = binding.ID
	}
	r.scriptKeys, r.scriptBindings = scriptKeys, scriptBindings
	return nil
}

func (r *Router) Script_keys() []uint16 {
	var keys []uint16
	for key := range r.scriptKeys {
		keys = append(keys, key)
	}
	slices.Sort(keys)
	return keys
}

func (r *Router) script_name(key uint16, numLock bool) string {
	// Python normalizes left/right modifiers before resolving reader modifiers.
	physical := key
	switch key {
	case KeyRightCtrl:
		key = KeyCtrl
	case KeyRightShift:
		key = KeyShift
	case KeyRightAlt:
		key = KeyAlt
	case KeyRightMeta:
		key = KeyMeta
	}
	if r.script_modifier(physical, numLock) {
		return "KEY_SCRIPT"
	}
	if r.reader_modifier(physical, numLock) {
		return "KEY_FENRIR"
	}
	switch key {
	case KeyCtrl:
		return "KEY_CTRL"
	case KeyShift:
		return "KEY_SHIFT"
	case KeyAlt:
		return "KEY_ALT"
	}
	name := C.libevdev_event_code_get_name(C.EV_KEY, C.uint(key))
	if name == nil {
		return ""
	}
	return C.GoString(name)
}

func (r *Router) script_binding(key uint16, numLock bool) (command.ID, bool) {
	active := r.script_modifier(key, numLock)
	if !active {
		for scriptKey := range r.scriptKeys {
			if r.script_modifier(scriptKey, numLock) && r.down(scriptKey) {
				active = true
				break
			}
		}
	}
	if !active {
		return "", false
	}
	names := map[string]bool{}
	for _, held := range r.keys {
		for code := range held {
			names[r.script_name(code, numLock)] = true
		}
	}
	names[r.script_name(key, numLock)] = true
	if !names["KEY_SCRIPT"] {
		return "", false
	}
	var keys []string
	for name := range names {
		keys = append(keys, name)
	}
	if id := r.scriptBindings[Script_chord(keys)]; id != "" {
		return id, true
	}
	// Modifier prefixes are silent. Nonmatching script chords are consumed.
	for _, name := range keys {
		switch name {
		case "KEY_SCRIPT", "KEY_FENRIR", "KEY_CTRL", "KEY_SHIFT", "KEY_ALT", "KEY_META":
		default:
			return command.Unbound, true
		}
	}
	return "", true
}