use super::errors::CodecError;
use serde::Serialize;
use std::num::ParseIntError;
use std::ops::Deref;
use std::{collections::HashMap, u64};

/// A number encoded as a sequence of words
#[derive(Debug, Clone, Serialize)]
pub struct EncodedPart {
    pub value: u64,
    pub words: Vec<String>,
}

/// A way (variant) to split input number
pub type EncodedSplit = Vec<EncodedPart>;

/// A number encoded as words, split in multiple ways
#[derive(Debug, Clone, Serialize)]
pub struct EncodedValue(Vec<EncodedSplit>);

impl EncodedValue {
    pub fn new(data: Vec<EncodedSplit>) -> Self {
        EncodedValue(data)
    }
}

impl Deref for EncodedValue {
    type Target = Vec<EncodedSplit>;

    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

/// The number value can be encoded as many word sets,
/// but decoded as one number. For partial values
/// and dictionary words (reasonable length), we can use
/// u64 (20-digit number), but the whole input text can
/// be longer than 20 digits, so we operate on String (<= 255).
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct DecodedValue(String);

impl DecodedValue {
    pub fn new(value: String) -> Result<Self, CodecError> {
        if value.len() > u8::MAX as usize {
            Err(CodecError::TextTooLong(value.len()))
        } else {
            Ok(Self(value))
        }
    }

    pub fn as_str(&self) -> &str {
        &self.0
    }

    pub fn parse(&self) -> Result<u64, ParseIntError> {
        self.0.parse()
    }

    pub fn len(&self) -> usize {
        self.0.len()
    }

    pub fn is_empty(&self) -> bool {
        self.0.is_empty()
    }

    pub fn value_len(&self) -> Result<DecodedLength, CodecError> {
        if self.len() == 0 {
            return Err(CodecError::EmptyValue);
        }
        DecodedLength::try_from(self.len())
    }
}

impl PartialEq<&str> for DecodedValue {
    fn eq(&self, other: &&str) -> bool {
        &self.0 == *other
    }
}

impl PartialEq<DecodedValue> for &str {
    fn eq(&self, other: &DecodedValue) -> bool {
        *self == &other.0
    }
}

#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
pub struct DecodedLength(u8);

impl DecodedLength {
    pub const fn from(value: u8) -> Self {
        Self(value)
    }
}

impl TryFrom<usize> for DecodedLength {
    type Error = CodecError;
    fn try_from(value: usize) -> Result<Self, CodecError> {
        if value > u8::MAX as usize {
            Err(CodecError::ValueLimitExceeded(value))
        } else {
            Ok(Self(value as u8))
        }
    }
}

// --- Dictionary ---

pub type DictEntryId = u64;

#[derive(Debug, Clone, PartialEq)]
pub struct DictEntry {
    pub id: Option<DictEntryId>,
    pub text: String,
    pub metadata: HashMap<String, String>,
}

impl DictEntry {
    pub fn new(id: Option<DictEntryId>, text: String) -> Self {
        DictEntry {
            id,
            text,
            metadata: HashMap::new(),
        }
    }
}

#[derive(Debug, Clone)]
pub struct Dict {
    pub name: String,
    pub entries: HashMap<DictEntryId, DictEntry>,
}

impl Dict {
    pub fn new(name: String) -> Self {
        Dict {
            name,
            entries: HashMap::new(),
        }
    }

    pub fn add_entry(&mut self, entry: DictEntry) {
        self.entries.insert(entry.id.unwrap(), entry);
    }
}