import gleam/string
import gleam/list
import gleam/result
import characters

pub const morse_code_list: MorseCodeList = characters.base_characters

pub const default_dot: String = "."

pub const default_dash: String = "-"

pub const default_space: String = "/"

pub const default_separator: String = " "

pub const default_language_num: String = language_num_latin

pub const default_is_uppercase: Bool = False

pub const default_to_uppercase: Bool = False

pub const language_num_latin: String = "1"

pub const language_num_numbers: String = "2"

pub const language_num_punctuation: String = "3"

pub const language_num_latin_extended: String = "4"

pub const language_num_cyrillic: String = "5"

pub const language_num_greek: String = "6"

pub const language_num_hebrew: String = "7"

pub const language_num_arabic: String = "8"

pub const language_num_persian: String = "9"

pub const language_num_japanese: String = "10"

pub const language_num_korean: String = "11"

pub const language_num_thai: String = "12"

pub type MorseCodeList =
    List(#(String, String, List(Bool)))

pub type MorseCodeError {
    MorseCodeError(msg: String)
}

pub type EncodeOptions {
    EncodeOptions(
        output_dot: String,
        output_dash: String,
        output_space: String,
        output_separator: String,
        is_uppercase: Bool,
        language_num: String,
    )
}

pub fn encode(
    input: String,
    morse_code_list: MorseCodeList,
    options: EncodeOptions,
) -> Result(String, MorseCodeError) {
    input
    |> string.to_graphemes
    |> list.try_map(fn(g: String) -> Result(String, MorseCodeError) {
        case g {
            " " | "\n" | "\r" | "\t" -> Ok(options.output_space)
            _ -> {
                let g: String = case options.is_uppercase {
                    True -> g
                    False -> string.uppercase(g)
                }
                case list_key_find(morse_code_list, g, options.language_num) {
                    Ok(bools) -> {
                        bools
                        |> list.map(fn(b: Bool) -> String {
                            case b {
                                True -> options.output_dash
                                False -> options.output_dot
                            }
                        })
                        |> string.join("")
                        |> Ok
                    }
                    Error(_) -> Error(MorseCodeError("Invalid symbol: " <> g))
                }
            }
        }
    })
    |> result.map(string.join(_, options.output_separator))
}

pub fn encode_to_string(
    input: String,
    morse_code_list: MorseCodeList,
    options: EncodeOptions,
) -> String {
    case encode(input, morse_code_list, options) {
        Ok(value) -> value
        Error(value) -> value.msg
    }
}

pub type DecodeOptions {
    DecodeOptions(
        input_dot: String,
        input_dash: String,
        input_space: String,
        input_separator: String,
        to_uppercase: Bool,
        language_num: String,
    )
}

pub fn decode(
    input: String,
    morse_code_list: MorseCodeList,
    options: DecodeOptions,
) -> Result(String, MorseCodeError) {
    input
    |> string.split(options.input_separator)
    |> list.try_map(fn(w: String) -> Result(String, MorseCodeError) {
        case True {
            _ if w == "" -> Ok("")
            _ if w == options.input_space -> Ok(" ")
            _ -> {
                w
                |> string.to_graphemes
                |> list.try_map(fn(g: String) -> Result(Bool, MorseCodeError) {
                    case True {
                        _ if g == options.input_dot -> Ok(False)
                        _ if g == options.input_dash -> Ok(True)
                        _ ->
                            Error(MorseCodeError(
                                "Invalid morse code symbol: " <> g,
                            ))
                    }
                })
                |> result.try(fn(bools: List(Bool)) -> Result(
                    String,
                    MorseCodeError,
                ) {
                    case
                        list_value_find(
                            morse_code_list,
                            bools,
                            options.language_num,
                        )
                    {
                        Ok(value) -> {
                            case options.to_uppercase {
                                True -> Ok(value)
                                False -> Ok(string.lowercase(value))
                            }
                        }
                        Error(_) ->
                            Error(MorseCodeError("Invalid symbol: " <> w))
                    }
                })
            }
        }
    })
    |> result.map(string.join(_, ""))
}

pub fn decode_to_string(
    input: String,
    morse_code_list: MorseCodeList,
    options: DecodeOptions,
) -> String {
    case decode(input, morse_code_list, options) {
        Ok(value) -> value
        Error(value) -> value.msg
    }
}

fn list_key_find(
    keys: List(#(String, String, List(Bool))),
    desired_key: String,
    language_num: String,
) -> Result(List(Bool), Nil) {
    case list.filter(keys, fn(k) { k.1 == desired_key }) {
        [] -> Error(Nil)
        [only_key] -> Ok(only_key.2)
        dublic_keys ->
            case list.filter(dublic_keys, fn(key) { key.0 == language_num }) {
                [] ->
                    list.at(dublic_keys, 0)
                    |> result.map(fn(key) { key.2 })
                [only_lang_key] -> Ok(only_lang_key.2)
                dublic_lang_keys ->
                    list.at(dublic_lang_keys, 0)
                    |> result.map(fn(key) { key.2 })
            }
    }
}

fn list_value_find(
    values: List(#(String, String, List(Bool))),
    desired_value: List(Bool),
    language_num: String,
) -> Result(String, Nil) {
    case list.filter(values, fn(v) { v.2 == desired_value }) {
        [] -> Error(Nil)
        [only_value] -> Ok(only_value.1)
        dublic_values ->
            case
                list.filter(dublic_values, fn(value) { value.0 == language_num })
            {
                [] ->
                    list.at(dublic_values, 0)
                    |> result.map(fn(value) { value.1 })
                [only_lang_value] -> Ok(only_lang_value.1)
                dublic_lang_values ->
                    list.at(dublic_lang_values, 0)
                    |> result.map(fn(value) { value.1 })
            }
    }
}

pub type ConvertOptions {
    ConvertOptions(
        input_dot: String,
        output_dot: String,
        input_dash: String,
        output_dash: String,
        input_space: String,
        output_space: String,
        input_separator: String,
        output_separator: String,
    )
}

pub fn convert(
    input: String,
    options: ConvertOptions,
) -> Result(String, MorseCodeError) {
    input
    |> string.to_graphemes
    |> list.try_map(fn(g: String) -> Result(String, MorseCodeError) {
        case True {
            _ if g == options.input_separator -> Ok(options.output_separator)
            _ if g == options.input_space -> Ok(options.output_space)
            _ if g == options.input_dot -> Ok(options.output_dot)
            _ if g == options.input_dash -> Ok(options.output_dash)
            _ -> Error(MorseCodeError("Invalid morse code symbol: " <> g))
        }
    })
    |> result.map(string.join(_, ""))
}

pub fn convert_to_string(input: String, options: ConvertOptions) -> String {
    case convert(input, options) {
        Ok(value) -> value
        Error(value) -> value.msg
    }
}