/*
 * Copyright (C) 2018 "IoT.bzh"
 * Author Sebastien Douheret <sebastien@iot.bzh>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package xdsserver

import (
	"fmt"

	"gerrit.automotivelinux.org/gerrit/src/xds/xds-server.git/lib/xsapiv1"
	"github.com/syncthing/syncthing/lib/sync"
)

// Terminals Represent a XDS terminals
type Terminals struct {
	*Context
	terms map[string]*ITERMINAL
}

// Mutex to make add/delete atomic
var tmMutex = sync.NewMutex()

// TerminalsConstructor Create a new instance of Model Terminal
func TerminalsConstructor(ctx *Context) *Terminals {
	return &Terminals{
		Context: ctx,
		terms:   make(map[string]*ITERMINAL),
	}
}

// New Create a new terminal
func (t *Terminals) New(cfg xsapiv1.TerminalConfig, targetID string) (*xsapiv1.TerminalConfig, error) {

	tmMutex.Lock()
	defer tmMutex.Unlock()

	var newT ITERMINAL

	// For now, only SSH term is supported
	switch cfg.Type {
	case xsapiv1.TypeTermSSH:
		newT = NewTermSSH(t.Context, cfg, targetID)
	default:
		return nil, fmt.Errorf("terminal type not set")
	}

	termCfg := newT.GetConfig()

	t.terms[termCfg.ID] = &newT

	termCfg.Status = xsapiv1.StatusTermEnable

	// Notify terminal add
	if err := t.events.Emit(xsapiv1.EVTTargetTerminalAdd, &termCfg, ""); err != nil {
		t.Log.Errorf("WS Emit EVTTargetTerminalAdd : %v", err)
	}

	return &termCfg, nil
}

// Free a specific terminal
func (t *Terminals) Free(id string) (*xsapiv1.TerminalConfig, error) {

	tmMutex.Lock()
	defer tmMutex.Unlock()

	tc := t.Get(id)
	if tc == nil {
		return nil, fmt.Errorf("Unknown id")
	}

	if _, err := (*tc).Close(); err != nil {
		return nil, err
	}

	resTerm := (*tc).GetConfig()

	delete(t.terms, id)

	// Notify terminal state change or add
	if err := t.events.Emit(xsapiv1.EVTTargetTerminalRemove, &resTerm, ""); err != nil {
		t.Log.Errorf("WS Emit EVTTargetTerminalRemove : %v", err)
	}

	return &resTerm, nil
}

// Get returns the terminal config or nil if not existing
func (t *Terminals) Get(id string) *ITERMINAL {
	if id == "" {
		return nil
	}
	tc, exist := t.terms[id]
	if !exist {
		return nil
	}
	return tc
}

// GetConfigArr returns the config of all terminals as an array
func (t *Terminals) GetConfigArr() []xsapiv1.TerminalConfig {
	tmMutex.Lock()
	defer tmMutex.Unlock()

	return t.getConfigArrUnsafe()
}

// getConfigArrUnsafe Same as GetConfigArr without mutex protection
func (t *Terminals) getConfigArrUnsafe() []xsapiv1.TerminalConfig {
	conf := []xsapiv1.TerminalConfig{}
	for _, v := range t.terms {
		conf = append(conf, (*v).GetConfig())
	}
	return conf
}

// Open adds a new terminal
func (t *Terminals) Open(id string, sess *ClientSession) (*xsapiv1.TerminalConfig, error) {
	tc := t.Get(id)
	if tc == nil {
		return nil, fmt.Errorf("Unknown id")
	}

	if sess.IOSocket == nil {
		return nil, fmt.Errorf("Websocket not established")
	}

	term, err := (*tc).Open(sess.IOSocket, sess.ID)

	// Notify term state change
	if errEmit := t.events.Emit(xsapiv1.EVTTargetTerminalStateChange, &term, sess.ID); errEmit != nil {
		t.Log.Errorf("WS Emit EVTTargetTerminalStateChange : %v", errEmit)
	}

	return term, err
}

// Close a specific terminal
func (t *Terminals) Close(id string, sess *ClientSession) (*xsapiv1.TerminalConfig, error) {
	tc := t.Get(id)
	if tc == nil {
		return nil, fmt.Errorf("Unknown id")
	}

	term, err := (*tc).Close()

	// Notify term state change
	if errEmit := t.events.Emit(xsapiv1.EVTTargetTerminalStateChange, &term, sess.ID); errEmit != nil {
		t.Log.Errorf("WS Emit EVTTargetTerminalStateChange : %v", errEmit)
	}

	return term, err
}

// Resize a specific terminal
func (t *Terminals) Resize(id string, cols, rows uint16, sess *ClientSession) (*xsapiv1.TerminalConfig, error) {
	tmMutex.Lock()
	defer tmMutex.Unlock()

	tc := t.Get(id)
	if tc == nil {
		return nil, fmt.Errorf("Unknown id")
	}

	term, err := (*tc).Resize(cols, rows)

	// Notify term state change
	if errEmit := t.events.Emit(xsapiv1.EVTTargetTerminalStateChange, &term, sess.ID); errEmit != nil {
		t.Log.Errorf("WS Emit EVTTargetTerminalStateChange : %v", errEmit)
	}

	return term, err
}

// Signal Send a Signal a specific terminal
func (t *Terminals) Signal(id, sigName string) error {
	tmMutex.Lock()
	defer tmMutex.Unlock()

	tc := t.Get(id)
	if tc == nil {
		return fmt.Errorf("Unknown id")
	}
	return (*tc).Signal(sigName)
}