// URTator - Urban Terror server browser and game launcher, written in
// Go.
//
// Copyright (c) 2016, Stanslav N. a.k.a pztrn (or p0z1tr0n)
// All rights reserved.
//
// Licensed under Terms and Conditions of GNU General Public License
// version 3 or any higher.
// ToDo: put full text of license here.

// This is translator - package which translates everything in languages
// other than en_US.
// Available only on unixes for now, Windows version in ToDo.
package translator

import (
    // stdlib
    "encoding/json"
    "fmt"
    "io/ioutil"
    "path/filepath"
    "strings"
)

type Translator struct {
    // Currently active language.
    Language string
    // Translations.
    translations map[string]map[string]string
    // Path to translations files.
    translationsPath string
}

// Formats string from passed map.
// We expect replaceable strings to be named as:
//
//      {{ VAR }}
//
// We will change whole "{{ VAR }}" to params["VAR"] value. E.g.:
//
//      data = "Version {{ version }}"
//      map = map[string]string{"version": "0.1"}
//
// will be formatted as:
//
//      result = "Version 0.1"
//
// Also note that we will replace ALL occurences of "{{ VAR }}" within string!
// All untranslated variables will not be touched at all.
func (t *Translator) formatFromMap(data string, params map[string]string) string {
    new_data := data
    for k, v := range params {
        new_data = strings.Replace(new_data, "{{ " + k + " }}", v, -1)
    }
    return new_data
}

// Translator initialization.
func (t *Translator) Initialize() {
    fmt.Println("Initializing translations...")

    // Initialize storages.
    t.translations = make(map[string]map[string]string)
    t.translationsPath = ""

    // Getting locale name from environment.
    // ToDo: Windows compatability. Possible reference:
    // https://github.com/cloudfoundry-attic/jibber_jabber/blob/master/jibber_jabber_windows.go
    t.detectLanguage()

    fmt.Println("Using translations for '" + t.Language + "'")

    err := t.detectTranslationsDirectory()
    if err == nil {
        t.loadTranslations()
    } else {
        fmt.Println("Skipping translations loading due to missing translations directory.")
    }
}

// Load translations into memory.
func (t *Translator) loadTranslations() {
    fmt.Println("Loading translations for language " + t.Language)

    t.translations[t.Language] = make(map[string]string)

    if t.translationsPath != "" {
        files_list, _ := ioutil.ReadDir(t.translationsPath)
        if len(files_list) > 0 {
            for i := range files_list {
                // Read file.
                file_path := filepath.Join(t.translationsPath, files_list[i].Name())
                file_data, _ := ioutil.ReadFile(file_path)
                var trans map[string]string
                json.Unmarshal(file_data, &trans)
                // Assign parsed translations to language code.
                t.translations[t.Language] = trans
            }
        }
    }
}

// Actual translation function.
// Parameters:
//   * str - raw string from source which we will try to translate.
//   * params - map[string]string with parameters to replace in string.
//
// If string wasn't found in loaded translations for current language
// we will use English as fallback.
// Translates passed data from loaded translations file.
// Returns passed data without changes if translation wasn't found.
func (t *Translator) Translate(data string, params map[string]string) string {
    val, ok := t.translations[t.Language][data]
    if !ok {
        if params != nil && len(params) > 0 {
            return t.formatFromMap(data, params)
        } else {
            return data
        }
    }

    if params != nil && len(params) > 0 {
        return t.formatFromMap(val, params)
    }

    return val
}