imag/src/storage/file.rs

use std::error::Error;
use std::fmt::{Debug, Display, Formatter};
use std::fmt;

use module::Module;
use super::parser::{FileHeaderParser, Parser, ParserError};
use storage::file_id::*;

use regex::Regex;

#[derive(Debug)]
#[derive(Clone)]
pub enum FileHeaderSpec {
    Null,
    Bool,
    Integer,
    UInteger,
    Float,
    Text,
    Key { name: String, value_type: Box<FileHeaderSpec> },
    Map { keys: Vec<FileHeaderSpec> },
    Array { allowed_types: Vec<FileHeaderSpec> },
}

#[derive(Debug)]
#[derive(Clone)]
pub enum FileHeaderData {
    Null,
    Bool(bool),
    Integer(i64),
    UInteger(u64),
    Float(f64),
    Text(String),
    Key { name: String, value: Box<FileHeaderData> },
    Map { keys: Vec<FileHeaderData> },
    Array { values: Box<Vec<FileHeaderData>> },
}

impl Display for FileHeaderSpec {

    fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
        match self {
            &FileHeaderSpec::Null       => write!(fmt, "NULL"),
            &FileHeaderSpec::Bool       => write!(fmt, "Bool"),
            &FileHeaderSpec::Integer    => write!(fmt, "Integer"),
            &FileHeaderSpec::UInteger   => write!(fmt, "UInteger"),
            &FileHeaderSpec::Float      => write!(fmt, "Float"),
            &FileHeaderSpec::Text       => write!(fmt, "Text"),
            &FileHeaderSpec::Key{name: ref n, value_type: ref vt} => {
                write!(fmt, "Key({:?}) -> {:?}", n, vt)
            }
            &FileHeaderSpec::Map{keys: ref ks} => {
                write!(fmt, "Map -> {:?}", ks)
            }
            &FileHeaderSpec::Array{allowed_types: ref at}  => {
                write!(fmt, "Array({:?})", at)
            }
        }
    }

}

impl FileHeaderData {

    pub fn matches_with(&self, r: &Regex) -> bool {
        match self {
            &FileHeaderData::Text(ref t) => r.is_match(&t[..]),
            &FileHeaderData::Key{name: ref n, value: ref val} => {
                r.is_match(n) || val.matches_with(r)
            },

            &FileHeaderData::Map{keys: ref dks} => {
                dks.iter().any(|x| x.matches_with(r))
            },

            &FileHeaderData::Array{values: ref vs} => {
                vs.iter().any(|x| x.matches_with(r))
            }

            _ => false,
        }
    }
}

pub struct MatchError<'a> {
    summary: String,
    expected: &'a FileHeaderSpec,
    found: &'a FileHeaderData
}

impl<'a> MatchError<'a> {

    pub fn new(s: String,
               ex: &'a FileHeaderSpec,
               found: &'a FileHeaderData) -> MatchError<'a> {
        MatchError {
            summary: s,
            expected: ex,
            found: found,
        }
    }

    pub fn format(&self) -> String {
        format!("MatchError: {:?}\nExpected: {:?}\nFound: {:?}\n",
               self.summary, self.expected, self.found)
    }
}

impl<'a> Error for MatchError<'a> {

    fn description(&self) -> &str {
        &self.summary[..]
    }

    fn cause(&self) -> Option<&Error> {
        None
    }

}

impl<'a> Debug for MatchError<'a> {

    fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
        write!(fmt, "{}", self.format());
        Ok(())
    }

}

impl<'a> Display for MatchError<'a> {

    fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
        write!(fmt, "{}", self.format());
        Ok(())
    }

}

pub fn match_header_spec<'a>(spec: &'a FileHeaderSpec, data: &'a FileHeaderData)
    -> Option<MatchError<'a>>
{
    debug!("Start matching:\n'{:?}'\non\n{:?}", spec, data);
    match (spec, data) {
        (&FileHeaderSpec::Null,     &FileHeaderData::Null)           => { }
        (&FileHeaderSpec::Bool,     &FileHeaderData::Bool(_))        => { }
        (&FileHeaderSpec::Integer,  &FileHeaderData::Integer(_))     => { }
        (&FileHeaderSpec::UInteger, &FileHeaderData::UInteger(_))    => { }
        (&FileHeaderSpec::Float,    &FileHeaderData::Float(_))       => { }
        (&FileHeaderSpec::Text,     &FileHeaderData::Text(_))        => { }

        (
            &FileHeaderSpec::Key{name: ref kname, value_type: ref vtype},
            &FileHeaderData::Key{name: ref n, value: ref val}
        ) => {
            debug!("Matching Key: '{:?}' == '{:?}', Value: '{:?}' == '{:?}'",
                    kname, n,
                    vtype, val);
            if kname != n {
                debug!("Keys not matching");
                unimplemented!();
            }
            return match_header_spec(&*vtype, &*val);
        }

        (
            &FileHeaderSpec::Map{keys: ref sks},
            &FileHeaderData::Map{keys: ref dks}
        ) => {
            debug!("Matching Map: '{:?}' == '{:?}'", sks, dks);

            for (s, d) in sks.iter().zip(dks.iter()) {
                let res = match_header_spec(s, d);
                if res.is_some() {
                    return res;
                }
            }
        }

        (
            &FileHeaderSpec::Array{allowed_types: ref vtypes},
            &FileHeaderData::Array{values: ref vs}
        ) => {
            debug!("Matching Array: '{:?}' == '{:?}'", vtypes, vs);
            for (t, v) in vtypes.iter().zip(vs.iter()) {
                let res = match_header_spec(t, v);
                if res.is_some() {
                    return res;
                }
            }
        }

        (k, v) => {
            return Some(MatchError::new(String::from("Expected type does not match found type"),
                                 k, v
                                 ))
        }
    }
    None
}

/*
 * Internal abstract view on a file. Does not exist on the FS and is just kept
 * internally until it is written to disk.
 */
pub struct File<'a> {
    owning_module   : &'a Module,
    header          : FileHeaderData,
    data            : String,
    id              : FileID,
}

impl<'a> File<'a> {

    pub fn new(module: &'a Module) -> File<'a> {
        let f = File {
            owning_module: module,
            header: FileHeaderData::Null,
            data: String::from(""),
            id: File::get_new_file_id(),
        };
        debug!("Create new File object: {:?}", f);
        f
    }

    pub fn from_parser_result(module: &Module, id: FileID, header: FileHeaderData, data: String) -> File {
        let f = File {
            owning_module: module,
            header: header,
            data: data,
            id: id,
        };
        debug!("Create new File object from parser result: {:?}", f);
        f
    }

    pub fn new_with_header(module: &Module, h: FileHeaderData) -> File {
        let f = File {
            owning_module: module,
            header: h,
            data: String::from(""),
            id: File::get_new_file_id(),
        };
        debug!("Create new File object with header: {:?}", f);
        f
    }

    pub fn new_with_data(module: &Module, d: String) -> File {
        let f = File {
            owning_module: module,
            header: FileHeaderData::Null,
            data: d,
            id: File::get_new_file_id(),
        };
        debug!("Create new File object with data: {:?}", f);
        f
    }

    pub fn new_with_content(module: &Module, h: FileHeaderData, d: String) -> File {
        let f = File {
            owning_module: module,
            header: h,
            data: d,
            id: File::get_new_file_id(),
        };
        debug!("Create new File object with content: {:?}", f);
        f
    }

    pub fn header(&self) -> FileHeaderData {
        self.header.clone()
    }

    pub fn data(&self) -> String {
        self.data.clone()
    }

    pub fn contents(&self) -> (FileHeaderData, String) {
        (self.header(), self.data())
    }

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

    pub fn owner(&self) -> &Module {
        self.owning_module
    }

    pub fn matches_with(&self, r: &Regex) -> bool {
        r.is_match(&self.data[..]) || self.header.matches_with(r)
    }

    fn get_new_file_id() -> FileID {
        use uuid::Uuid;
        FileID::new(FileIDType::UUID, Uuid::new_v4().to_hyphenated_string())
    }
}

impl<'a> Display for File<'a> {

    fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
        write!(fmt,
"[File] Owner : '{:?}'
        FileID: '{:?}'
        Header: '{:?}'
        Data  : '{:?}'",
               self.owning_module,
               self.header,
               self.data,
               self.id);
        Ok(())
    }

}

impl<'a> Debug for File<'a> {

    fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
        write!(fmt,
"[File] Owner : '{:?}'
        FileID: '{:?}'
        Header: '{:?}'
        Data  : '{:?}'",
               self.owning_module,
               self.header,
               self.data,
               self.id);
        Ok(())
    }

}

#[cfg(test)]
mod test {
    // we use the JSON parser here, so we can generate FileHeaderData
    use storage::json::parser::JsonHeaderParser;
    use super::match_header_spec;
    use storage::parser::{FileHeaderParser, ParserError};
    use storage::file::FileHeaderData as FHD;
    use storage::file::FileHeaderSpec as FHS;

    #[test]
    fn test_spec_matching() {
        let text = String::from("{\"a\": 1, \"b\": -2}");
        let spec = FHS::Map {
            keys: vec![
                FHS::Key {
                    name: String::from("a"),
                    value_type: Box::new(FHS::UInteger)
                },
                FHS::Key {
                    name: String::from("b"),
                    value_type: Box::new(FHS::Integer)
                }
            ]
        };

        let parser  = JsonHeaderParser::new(Some(spec.clone()));
        let datares = parser.read(Some(text.clone()));
        assert!(datares.is_ok(), "Text could not be parsed: '{}'", text);
        let data = datares.unwrap();

        let matchres = match_header_spec(&spec, &data);
        assert!(matchres.is_none(), "Matching returns error: {:?}", matchres);
    }
}