upend/base/src/entry.rs

use crate::addressing::{Address, Addressable};
use crate::error::UpEndError;
use crate::hash::{b58_decode, sha256hash, AsMultihash, AsMultihashError, UpMultihash};
use chrono::NaiveDateTime;
use serde::{Deserialize, Serialize};
use std::convert::TryFrom;
use std::io::{Cursor, Write};
use url::Url;

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Entry {
    pub entity: Address,
    pub attribute: String,
    pub value: EntryValue,
    pub provenance: String,
    pub timestamp: NaiveDateTime,
}

#[derive(Debug, Clone)]
pub struct ImmutableEntry(pub Entry);

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct InvariantEntry {
    pub attribute: String,
    pub value: EntryValue,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(tag = "t", content = "c")]
pub enum EntryValue {
    Address(Address),
    Number(f64),
    Null,
}

impl Default for Entry {
    fn default() -> Self {
        Self {
            entity: Address::Uuid(uuid::Uuid::nil()),
            attribute: Default::default(),
            value: EntryValue::Null,
            provenance: "SYSTEM".into(),
            timestamp: NaiveDateTime::from_timestamp_opt(0, 0).unwrap(),
        }
    }
}

impl TryFrom<&InvariantEntry> for Entry {
    type Error = UpEndError;

    fn try_from(invariant: &InvariantEntry) -> Result<Self, Self::Error> {
        Ok(Entry {
            entity: invariant.entity()?,
            attribute: invariant.attribute.clone(),
            value: invariant.value.clone(),
            provenance: "INVARIANT".to_string(),
            ..Default::default()
        })
    }
}

impl InvariantEntry {
    pub fn entity(&self) -> Result<Address, UpEndError> {
        let mut entity = Cursor::new(vec![0u8; 0]);
        entity
            .write_all(self.attribute.as_bytes())
            .map_err(UpEndError::from_any)?;
        entity
            .write_all(self.value.to_string().as_bytes())
            .map_err(UpEndError::from_any)?;
        Ok(Address::Hash(
            sha256hash(entity.into_inner()).map_err(UpEndError::from_any)?,
        ))
    }
}

impl std::fmt::Display for Entry {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{} | {} | {}", self.entity, self.attribute, self.value)
    }
}

impl AsMultihash for Entry {
    fn as_multihash(&self) -> Result<UpMultihash, AsMultihashError> {
        let mut result = Cursor::new(vec![0u8; 0]);
        result.write_all(
            self.entity
                .encode()
                .map_err(|e| AsMultihashError(e.to_string()))?
                .as_slice(),
        )?;
        result.write_all(self.attribute.as_bytes())?;
        result.write_all(self.value.to_string().as_bytes())?;
        sha256hash(result.get_ref())
    }
}

impl AsMultihash for InvariantEntry {
    fn as_multihash(&self) -> Result<UpMultihash, AsMultihashError> {
        Entry::try_from(self)
            .map_err(|e| AsMultihashError(e.to_string()))?
            .as_multihash()
    }
}

impl EntryValue {
    pub fn to_string(&self) -> String {
        let (type_char, content) = match self {
            EntryValue::Address(address) => ('O', address.to_string()),
            EntryValue::Number(n) => ('N', n.to_string()),
            EntryValue::Null => ('X', "".to_string()),
        };

        format!("{}{}", type_char, content)
    }

    pub fn guess_from<S: AsRef<str>>(string: S) -> Result<Self, UpEndError> {
        let string = string.as_ref();
        match string.parse::<f64>() {
            Ok(num) => Ok(EntryValue::Number(num)),
            Err(_) => {
                if let Ok(url) = Url::parse(string) {
                    Ok(EntryValue::Address(Address::Url(url)))
                } else {
                    Ok(EntryValue::Address(string.address()?))
                }
            }
        }
    }
}

impl std::str::FromStr for EntryValue {
    type Err = UpEndError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        if s.len() < 2 {
            match s.chars().next() {
                Some('X') => Ok(EntryValue::Null),
                _ => Err(UpEndError::EntryValueInvalid(s.to_string())),
            }
        } else {
            let (type_char, content) = s.split_at(1);
            match (type_char, content) {
                ("N", content) => {
                    if let Ok(n) = content.parse::<f64>() {
                        Ok(EntryValue::Number(n))
                    } else {
                        Err(UpEndError::EntryValueInvalid(s.to_string()))
                    }
                }
                ("O", content) => {
                    if let Ok(addr) = b58_decode(content).and_then(|v| Address::decode(&v)) {
                        Ok(EntryValue::Address(addr))
                    } else {
                        Err(UpEndError::EntryValueInvalid(s.to_string()))
                    }
                }
                _ => Err(UpEndError::EntryValueInvalid(s.to_string())),
            }
        }
    }
}

impl From<Url> for EntryValue {
    fn from(value: Url) -> Self {
        EntryValue::Address(Address::Url(value))
    }
}

impl std::fmt::Display for EntryValue {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        let (entry_type, entry_value) = match self {
            EntryValue::Address(address) => ("ADDRESS", address.to_string()),
            EntryValue::Number(n) => ("NUMBER", n.to_string()),
            EntryValue::Null => ("NULL", "NULL".to_string()),
        };
        write!(f, "{}: {}", entry_type, entry_value)
    }
}

impl From<f64> for EntryValue {
    fn from(num: f64) -> Self {
        Self::Number(num)
    }
}

impl From<Address> for EntryValue {
    fn from(address: Address) -> Self {
        Self::Address(address)
    }
}

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

    #[test]
    fn test_value_from_to_string() -> Result<(), UpEndError> {
        let entry = EntryValue::Address("hello".address().unwrap());
        let encoded = entry.to_string();
        let decoded = encoded.parse::<EntryValue>().unwrap();
        assert_eq!(entry, decoded);

        let entry = EntryValue::Number(1337.93);
        let encoded = entry.to_string();
        let decoded = encoded.parse::<EntryValue>().unwrap();
        assert_eq!(entry, decoded);

        let entry = EntryValue::Address(Address::Url(Url::parse("https://upend.dev").unwrap()));
        let encoded = entry.to_string();
        let decoded = encoded.parse::<EntryValue>().unwrap();
        assert_eq!(entry, decoded);

        let entry = EntryValue::Address("".address().unwrap());
        let encoded = entry.to_string();
        let decoded = encoded.parse::<EntryValue>().unwrap();
        assert_eq!(entry, decoded);

        let entry = EntryValue::Null;
        let encoded = entry.to_string();
        let decoded = encoded.parse::<EntryValue>().unwrap();
        assert_eq!(entry, decoded);

        Ok(())
    }

    #[test]
    fn test_into() {
        assert_eq!(EntryValue::Number(1337.93), 1337.93.into());
        let addr = Address::Url(Url::parse("https://upend.dev").unwrap());
        assert_eq!(EntryValue::Address(addr.clone()), addr.into());
    }

    #[test]
    fn test_guess_value() {
        assert_eq!(
            EntryValue::guess_from("UPEND").unwrap(),
            EntryValue::Address("UPEND".address().unwrap())
        );
        assert_eq!(
            EntryValue::guess_from("1337.93").unwrap(),
            EntryValue::Number(1337.93)
        );
        assert_eq!(
            EntryValue::guess_from("https://upend.dev").unwrap(),
            EntryValue::Address(Address::Url(Url::parse("https://upend.dev").unwrap()))
        );
    }
}