package xorg

/*
#include "commands_native.h"
#include <X11/XKBlib.h>
*/
import "C"

import (
	"context"
	"errors"
	"fmt"
	"git.stormux.org/storm/cthulhu/internal/input"
	"strings"
)

type bindingUpdate struct {
	tentacles        []input.BindingOverride
	replaceTentacles bool
	ocrForeground    uint64
	ocrReview        *bool
	ocrPending       *bool
	layout           input.KeyboardLayout
	modifiers        []string
	replaceKeyboard  bool
	ctx              context.Context
	overrides        []input.BindingOverride
	result           chan error
}

// SetKeyBindings validates and acknowledges a native update after the current
// chord releases. Before Start it sets the configuration used at startup.
func (listener *CommandListener) SetKeyBindings(ctx context.Context, overrides []input.BindingOverride) error {
	return listener.update_keyboard(ctx, bindingUpdate{overrides: overrides})
}

// SetKeyboardConfiguration applies layout, modifier keys, and shortcuts together
// after held keys release. A failed native grab retains the whole old setup.
func (listener *CommandListener) SetKeyboardConfiguration(ctx context.Context, layout input.KeyboardLayout, modifiers []string, overrides []input.BindingOverride) error {
	if layout != input.DesktopKeyboardLayout && layout != input.LaptopKeyboardLayout {
		return fmt.Errorf("invalid keyboard layout %d", layout)
	}
	if _, err := command_modifier_symbols(modifiers); err != nil {
		return err
	}
	return listener.update_keyboard(ctx, bindingUpdate{layout: layout, modifiers: append([]string(nil), modifiers...), overrides: overrides, replaceKeyboard: true})
}

func (listener *CommandListener) update_keyboard(ctx context.Context, update bindingUpdate) error {
	if err := ctx.Err(); err != nil {
		return err
	}
	if err := input.ValidateBindingOverrides(update.overrides); err != nil {
		return err
	}
	update.overrides = input.CloneBindingOverrides(update.overrides)
	listener.mutex.Lock()
	if listener.done == nil {
		if update.replaceTentacles {
			listener.tentacleBindings = update.tentacles
		} else {
			listener.bindingOverrides = update.overrides
		}
		if update.replaceKeyboard {
			listener.layout, listener.modifiers = update.layout, update.modifiers
		}
		listener.mutex.Unlock()
		return nil
	}
	done := listener.done
	listener.mutex.Unlock()
	update.ctx, update.result = ctx, make(chan error, 1)
	select {
	case listener.bindingUpdates <- update:
	case <-done:
		return errors.New("command listener has stopped")
	case <-ctx.Done():
		return ctx.Err()
	}
	select {
	case err := <-update.result:
		return err
	case <-done:
		return errors.New("command listener has stopped")
	}
}

// SetTentacleBindings replaces all runtime suggestions atomically after held
// keys release. Native failure restores the previous complete configuration.
func (listener *CommandListener) SetTentacleBindings(ctx context.Context, bindings []input.BindingOverride) error {
	if err := input.ValidateTentacleBindings(bindings); err != nil {
		return err
	}
	return listener.update_keyboard(ctx, bindingUpdate{replaceTentacles: true, tentacles: input.CloneBindingOverrides(bindings)})
}

func (listener *CommandListener) TentacleBindings() []input.BindingOverride {
	listener.registrationMutex.RLock()
	defer listener.registrationMutex.RUnlock()
	return input.CloneBindingOverrides(listener.appliedTentacles)
}

func (listener *CommandListener) publishTentacleBindings(merged []input.BindingOverride) {
	listener.registrationMutex.Lock()
	defer listener.registrationMutex.Unlock()
	listener.appliedTentacles = nil
	for _, binding := range merged {
		if strings.HasPrefix(string(binding.Command), "tentacle/") {
			listener.appliedTentacles = append(listener.appliedTentacles, input.CloneBindingOverrides([]input.BindingOverride{binding})[0])
		}
	}
}

func command_modifier_symbols(modifiers []string) ([]uint32, error) {
	var symbols []uint32
	for _, name := range modifiers {
		switch name {
		case "Insert":
			symbols = append(symbols, 0xff63)
		case "KP_Insert":
			symbols = append(symbols, 0xff9e)
		case "Caps_Lock":
			symbols = append(symbols, 0xffe5)
		default:
			return nil, fmt.Errorf("command modifier %q is unsupported; use Insert, KP_Insert, or Caps_Lock", name)
		}
	}
	return symbols, nil
}

func resolvedBindings(layout input.KeyboardLayout, browse bool, overrides []input.BindingOverride) input.CommandBindings {
	bindings, _ := input.ResolveCommandBindings(layout, browse, overrides)
	return bindings
}

func configureNativeBindings(device *C.CommandDevice, layout input.KeyboardLayout, modifiers []string, overrides []input.BindingOverride) error {
	return configure_native_bindings(device, layout, modifiers, overrides, false)
}

func configure_native_bindings(device *C.CommandDevice, layout input.KeyboardLayout, modifiers []string, overrides []input.BindingOverride, ocrReview bool, pending ...bool) error {
	symbols, err := command_modifier_symbols(modifiers)
	if err != nil {
		return err
	}
	var insertCode, keypadCode, capsCode C.int
	for _, symbol := range symbols {
		code := C.XKeysymToKeycode(device.display, C.KeySym(symbol))
		if code == 0 {
			return fmt.Errorf("Cthulhu modifier %x is unavailable on this X11 keymap", symbol)
		}
		switch symbol {
		case 0xff63:
			insertCode = C.int(code)
		case 0xff9e:
			keypadCode = C.int(code)
		case 0xffe5:
			capsCode = C.int(code)
		}
	}
	global := resolvedBindings(layout, false, overrides)
	browse := resolvedBindings(layout, true, overrides)
	if device.bypass != 0 {
		global = input.BypassCommandBindings(global)
		browse = global
	} else if ocrReview {
		browse = input.OCRCommandBindings(global)
		if len(pending) > 0 && pending[0] {
			browse = input.OCRPendingBindings(global)
		}
	}
	customizedBrowse := make(map[input.CommandChord]bool)
	for _, override := range overrides {
		if override.Layout == layout && override.Scope == "browse" {
			for _, key := range override.Keys {
				chord, _ := input.ParseCommandChord(key)
				customizedBrowse[chord] = true
			}
		}
	}
	var native []C.NativeBinding
	var extraModifierMask uint16
	for chord, command := range browse {
		if chord.CthulhuModifier {
			extraModifierMask |= chord.Modifiers & (8 | 64)
			// Such commands are delivered after a screen-reader modifier grab.
			// Validate that the native keymap can actually produce the symbol.
			code := C.XKeysymToKeycode(device.display, C.KeySym(chord.Symbol))
			if code == 0 || uint32(C.XkbKeycodeToKeysym(device.display, code, 0, 0)) != chord.Symbol {
				return fmt.Errorf("key %s is unavailable as a base key on this X11 keymap", input.FormatCommandChord(chord))
			}
			continue
		}
		value := C.NativeBinding{symbol: C.ulong(chord.Symbol), modifiers: C.uint(chord.Modifiers)}
		if global[chord] == "" || ocrReview {
			value.browseOnly = 1
		}
		if customizedBrowse[chord] && !ocrReview {
			value.probe = 1
		}
		if command == input.DocumentActivate {
			value.activate = 1
		}
		native = append(native, value)
	}
	// Own Control/Shift from their press in temporary review. Otherwise the
	// application can see a modifier press whose release the arrow grab owns.
	// Unbound chords are replayed whole after all their physical keys release.
	if device.bypass == 0 && ocrReview && !(len(pending) > 0 && pending[0]) {
		for _, symbol := range []uint32{0xffe1, 0xffe2, 0xffe3, 0xffe4} {
			for _, mask := range []uint16{0, 1, 4, 5} {
				native = append(native, C.NativeBinding{symbol: C.ulong(symbol), modifiers: C.uint(mask), browseOnly: 1})
			}
		}
	}
	var first *C.NativeBinding
	if len(native) != 0 {
		first = &native[0]
	}
	if err := C.configure_command_bindings(device, first, C.int(len(native)), C.uint(extraModifierMask), insertCode, keypadCode, capsCode); err != 0 {
		return fmt.Errorf("change X11 key bindings: native error %d (key unavailable or grabbed by another application)", int(err))
	}
	return nil
}