use std::fmt;
use std::str::FromStr;

use serde::{Deserialize, Serialize};

use crate::prelude::*;

pub use radicle_crdt::clock::Physical as Timestamp;

/// Author.
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
pub struct Author {
    pub id: NodeId,
}

impl Author {
    pub fn new(id: NodeId) -> Self {
        Self { id }
    }

    pub fn id(&self) -> &NodeId {
        &self.id
    }
}

#[derive(thiserror::Error, Debug)]
pub enum ReactionError {
    #[error("invalid reaction")]
    InvalidReaction,
}

#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Copy, Clone, Serialize, Deserialize)]
#[serde(transparent)]
pub struct Reaction {
    pub emoji: char,
}

impl Reaction {
    pub fn new(emoji: char) -> Result<Self, ReactionError> {
        if emoji.is_whitespace() || emoji.is_ascii() || emoji.is_alphanumeric() {
            return Err(ReactionError::InvalidReaction);
        }
        Ok(Self { emoji })
    }
}

impl FromStr for Reaction {
    type Err = ReactionError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let mut chars = s.chars();
        let first = chars.next().ok_or(ReactionError::InvalidReaction)?;

        // Reactions should not consist of more than a single emoji.
        if chars.next().is_some() {
            return Err(ReactionError::InvalidReaction);
        }
        Reaction::new(first)
    }
}

#[derive(thiserror::Error, Debug)]
pub enum TagError {
    #[error("invalid tag name: `{0}`")]
    InvalidName(String),
}

#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Clone, Serialize, Deserialize)]
#[serde(transparent)]
pub struct Tag(String);

impl Tag {
    pub fn new(name: impl Into<String>) -> Result<Self, TagError> {
        let name = name.into();

        if name.chars().any(|c| c.is_whitespace()) || name.is_empty() {
            return Err(TagError::InvalidName(name));
        }
        Ok(Self(name))
    }

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

impl FromStr for Tag {
    type Err = TagError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        Self::new(s)
    }
}

impl From<Tag> for String {
    fn from(Tag(name): Tag) -> Self {
        name
    }
}

/// RGB color.
#[derive(Debug, PartialEq, Eq, Hash, Clone)]
pub struct Color(u32);

#[derive(thiserror::Error, Debug)]
pub enum ColorConversionError {
    #[error("invalid format: expect '#rrggbb'")]
    InvalidFormat,
    #[error(transparent)]
    ParseInt(#[from] std::num::ParseIntError),
}

impl fmt::Display for Color {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "#{:06x}", self.0)
    }
}

impl FromStr for Color {
    type Err = ColorConversionError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let hex = s.replace('#', "").to_lowercase();

        if hex.chars().count() != 6 {
            return Err(ColorConversionError::InvalidFormat);
        }

        match u32::from_str_radix(&hex, 16) {
            Ok(n) => Ok(Color(n)),
            Err(e) => Err(e.into()),
        }
    }
}

impl Serialize for Color {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: serde::ser::Serializer,
    {
        let s = self.to_string();
        serializer.serialize_str(&s)
    }
}

impl<'a> Deserialize<'a> for Color {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: serde::de::Deserializer<'a>,
    {
        let color = String::deserialize(deserializer)?;
        Self::from_str(&color).map_err(serde::de::Error::custom)
    }
}

#[cfg(test)]
mod test {
    use super::*;

    #[test]
    fn test_color() {
        let c = Color::from_str("#ffccaa").unwrap();
        assert_eq!(c.to_string(), "#ffccaa".to_owned());
        assert_eq!(serde_json::to_string(&c).unwrap(), "\"#ffccaa\"".to_owned());
        assert_eq!(serde_json::from_str::<'_, Color>("\"#ffccaa\"").unwrap(), c);

        let c = Color::from_str("#0000aa").unwrap();
        assert_eq!(c.to_string(), "#0000aa".to_owned());

        let c = Color::from_str("#aa0000").unwrap();
        assert_eq!(c.to_string(), "#aa0000".to_owned());

        let c = Color::from_str("#00aa00").unwrap();
        assert_eq!(c.to_string(), "#00aa00".to_owned());

        Color::from_str("#aa00").unwrap_err();
        Color::from_str("#abc").unwrap_err();
    }
}