use std::{fs::File, sync::LazyLock};

use ron::de::from_reader;
use serde::Deserialize;
use strum::EnumCount;
use strum_macros::EnumCount;
use tracing::{event, Level};

use crate::{consts, utils};

#[derive(Debug, Clone, EnumCount, Deserialize)]
pub enum Sentence {
    MainTitle = 0,
    CreateNewRecipe,
    UnpublishedRecipes,
    UntitledRecipe,

    Name,
    EmailAddress,
    Password,

    SignOut,
    Save,
    NotLoggedIn,

    DatabaseError,

    // Sign in page.
    SignInMenu,
    SignInTitle,
    SignInButton,
    WrongEmailOrPassword,

    // Sign up page.
    SignUpMenu,
    SignUpTitle,
    SignUpButton,
    SignUpEmailSent,
    SignUpFollowEmailLink,
    SignUpEmailValidationSuccess,
    SignUpValidationExpired,
    SignUpValidationErrorTryAgain,
    ChooseAPassword,
    ReEnterPassword,
    AccountMustBeValidatedFirst,
    InvalidEmail,
    PasswordDontMatch,
    InvalidPassword,
    EmailAlreadyTaken,
    UnableToSendEmail,

    // Validation.
    ValidationSuccessful,
    ValidationExpired,
    ValidationErrorTryToSignUpAgain,
    ValidationError,
    ValidationUserAlreadyExists,

    // Reset password page.
    LostPassword,
    AskResetButton,
    AskResetAlreadyLoggedInError,
    AskResetEmailAlreadyResetError,
    AskResetFollowEmailLink,
    AskResetEmailSent,
    AskResetTokenMissing,
    AskResetTokenExpired,
    PasswordReset,
    EmailUnknown,
    UnableToSendResetEmail,

    // Profile
    ProfileTitle,
    ProfileEmail,
    ProfileNewPassword,
    ProfileFollowEmailLink,
    ProfileEmailSent,
    ProfileSaved,

    // Recipe.
    RecipeNotAllowedToEdit,
    RecipeNotAllowedToView,
    RecipeNotFound,
    RecipeTitle,
    RecipeDescription,
    RecipeServings,
    RecipeEstimatedTime,
    RecipeDifficulty,
    RecipeDifficultyEasy,
    RecipeDifficultyMedium,
    RecipeDifficultyHard,
    RecipeTags,
    RecipeLanguage,
    RecipeIsPublished,
    RecipeDelete,
    RecipeAddAGroup,
    RecipeRemoveGroup,
    RecipeGroupName,
    RecipeGroupComment,
    RecipeAddAStep,
    RecipeRemoveStep,
    RecipeStepAction,
    RecipeAddAnIngredient,
    RecipeRemoveIngredient,
    RecipeIngredientName,
    RecipeIngredientQuantity,
    RecipeIngredientUnit,
    RecipeIngredientComment,
}

pub const DEFAULT_LANGUAGE_CODE: &str = "en";
pub const PLACEHOLDER_SUBSTITUTE: &str = "{}";

#[derive(Clone)]
pub struct Tr {
    lang: &'static Language,
}

impl Tr {
    pub fn new(code: &str) -> Self {
        Self {
            lang: get_language_translation(code),
        }
    }

    pub fn t(&self, sentence: Sentence) -> &'static str {
        self.lang.get(sentence)
    }

    pub fn tp(&self, sentence: Sentence, params: &[Box<dyn ToString + Send>]) -> String {
        let text = self.lang.get(sentence);
        let params_as_string: Vec<String> = params.iter().map(|p| p.to_string()).collect();
        utils::substitute(
            text,
            PLACEHOLDER_SUBSTITUTE,
            &params_as_string
                .iter()
                .map(AsRef::as_ref)
                .collect::<Vec<_>>(),
        )
    }

    pub fn current_lang_code(&self) -> &str {
        &self.lang.code
    }
}

// #[macro_export]
// macro_rules! t {
//     ($self:expr, $str:expr) => {
//         $self.t($str)
//     };
//     ($self:expr, $str:expr, $( $x:expr ),+ ) => {
//         {
//             let mut result = $self.t($str);
//             $( result = result.replacen("{}", &$x.to_string(), 1); )+
//             result
//         }
//     };
// }

#[derive(Debug, Deserialize)]
struct StoredLanguage {
    code: String,
    name: String,
    translation: Vec<(Sentence, String)>,
}

#[derive(Debug)]
struct Language {
    code: String,
    name: String,
    translation: Vec<String>,
}

impl Language {
    pub fn from_stored_language(stored_language: StoredLanguage) -> Self {
        Self {
            code: stored_language.code,
            name: stored_language.name,
            translation: {
                let mut translation = vec![String::new(); Sentence::COUNT];
                for (sentence, text) in stored_language.translation {
                    translation[sentence as usize] = text;
                }
                translation
            },
        }
    }

    pub fn get(&'static self, sentence: Sentence) -> &'static str {
        let text: &str = self
            .translation
            .get(sentence.clone() as usize)
            .unwrap()
            .as_ref();
        if text.is_empty() && self.code != DEFAULT_LANGUAGE_CODE {
            return get_language_translation(DEFAULT_LANGUAGE_CODE).get(sentence);
        }
        text
    }
}

pub fn available_languages() -> Vec<(&'static str, &'static str)> {
    TRANSLATIONS
        .iter()
        .map(|tr| (tr.code.as_ref(), tr.name.as_ref()))
        .collect()
}

pub fn available_codes() -> Vec<&'static str> {
    TRANSLATIONS.iter().map(|tr| tr.code.as_ref()).collect()
}

fn get_language_translation(code: &str) -> &'static Language {
    for lang in TRANSLATIONS.iter() {
        if lang.code == code {
            return lang;
        }
    }

    event!(
        Level::WARN,
        "Unable to find translation for language {}",
        code
    );

    if code != DEFAULT_LANGUAGE_CODE {
        get_language_translation(DEFAULT_LANGUAGE_CODE)
    } else {
        // 'DEFAULT_LANGUAGE_CODE' must exist.
        panic!("Unable to find language {}", code);
    }
}

static TRANSLATIONS: LazyLock<Vec<Language>> =
    LazyLock::new(|| match File::open(consts::TRANSLATION_FILE) {
        Ok(file) => {
            let stored_languages: Vec<StoredLanguage> = from_reader(file).unwrap_or_else(|error| {
                {
                    panic!(
                        "Failed to read translation file {}: {}",
                        consts::TRANSLATION_FILE,
                        error
                    )
                }
            });
            stored_languages
                .into_iter()
                .map(Language::from_stored_language)
                .collect()
        }
        Err(error) => {
            panic!(
                "Failed to open translation file {}: {}",
                consts::TRANSLATION_FILE,
                error
            )
        }
    });