use crate::serde::{DeserializerError, SerializerError};
use serde_json::Error as SerdeJsonError;
use std::{error, fmt, io};

pub use heed::Error as HeedError;
pub use fst::Error as FstError;
pub use bincode::Error as BincodeError;

pub type MResult<T> = Result<T, Error>;

#[derive(Debug)]
pub enum Error {
    Io(io::Error),
    IndexAlreadyExists,
    MissingPrimaryKey,
    SchemaMissing,
    WordIndexMissing,
    MissingDocumentId,
    MaxFieldsLimitExceeded,
    Schema(meilisearch_schema::Error),
    Zlmdb(heed::Error),
    Fst(fst::Error),
    SerdeJson(SerdeJsonError),
    Bincode(bincode::Error),
    Serializer(SerializerError),
    Deserializer(DeserializerError),
    UnsupportedOperation(UnsupportedOperation),
}

impl From<io::Error> for Error {
    fn from(error: io::Error) -> Error {
        Error::Io(error)
    }
}

impl From<PestError<Rule>> for Error {
    fn from(error: PestError<Rule>) -> Error {
        Error::FilterParseError(error.renamed_rules(|r| {
            let s  = match r {
                Rule::or => "OR",
                Rule::and => "AND",
                Rule::not => "NOT",
                Rule::string => "string",
                Rule::word => "word",
                Rule::greater => "field>value",
                Rule::less => "field<value",
                Rule::eq => "field:value",
                Rule::leq => "field<=value",
                Rule::geq => "field>=value",
                Rule::key => "key",
                _ => "other",
            };
            s.to_string()
        }))
    }
} 

impl From<meilisearch_schema::Error> for Error {
    fn from(error: meilisearch_schema::Error) -> Error {
        Error::Schema(error)
    }
}

impl From<HeedError> for Error {
    fn from(error: HeedError) -> Error {
        Error::Zlmdb(error)
    }
}

impl From<FstError> for Error {
    fn from(error: FstError) -> Error {
        Error::Fst(error)
    }
}

impl From<SerdeJsonError> for Error {
    fn from(error: SerdeJsonError) -> Error {
        Error::SerdeJson(error)
    }
}

impl From<BincodeError> for Error {
    fn from(error: BincodeError) -> Error {
        Error::Bincode(error)
    }
}

impl From<SerializerError> for Error {
    fn from(error: SerializerError) -> Error {
        Error::Serializer(error)
    }
}

impl From<DeserializerError> for Error {
    fn from(error: DeserializerError) -> Error {
        Error::Deserializer(error)
    }
}

impl From<UnsupportedOperation> for Error {
    fn from(op: UnsupportedOperation) -> Error {
        Error::UnsupportedOperation(op)
    }
}

impl fmt::Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        use self::Error::*;
        match self {
            Io(e) => write!(f, "{}", e),
            IndexAlreadyExists => write!(f, "index already exists"),
            MissingPrimaryKey => write!(f, "schema cannot be built without a primary key"),
            SchemaMissing => write!(f, "this index does not have a schema"),
            WordIndexMissing => write!(f, "this index does not have a word index"),
            MissingDocumentId => write!(f, "document id is missing"),
            MaxFieldsLimitExceeded => write!(f, "maximum number of fields in a document exceeded"),
            Schema(e) => write!(f, "schema error; {}", e),
            Zlmdb(e) => write!(f, "heed error; {}", e),
            Fst(e) => write!(f, "fst error; {}", e),
            SerdeJson(e) => write!(f, "serde json error; {}", e),
            Bincode(e) => write!(f, "bincode error; {}", e),
            Serializer(e) => write!(f, "serializer error; {}", e),
            Deserializer(e) => write!(f, "deserializer error; {}", e),
            UnsupportedOperation(op) => write!(f, "unsupported operation; {}", op),
        }
    }
}

impl error::Error for Error {}

#[derive(Debug)]
pub enum UnsupportedOperation {
    SchemaAlreadyExists,
    CannotUpdateSchemaPrimaryKey,
    CannotReorderSchemaAttribute,
    CanOnlyIntroduceNewSchemaAttributesAtEnd,
    CannotRemoveSchemaAttribute,
}

impl fmt::Display for UnsupportedOperation {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        use self::UnsupportedOperation::*;
        match self {
            SchemaAlreadyExists => write!(f, "Cannot update index which already have a schema"),
            CannotUpdateSchemaPrimaryKey => write!(f, "Cannot update the primary key of a schema"),
            CannotReorderSchemaAttribute => write!(f, "Cannot reorder the attributes of a schema"),
            CanOnlyIntroduceNewSchemaAttributesAtEnd => {
                write!(f, "Can only introduce new attributes at end of a schema")
            }
            CannotRemoveSchemaAttribute => write!(f, "Cannot remove attributes from a schema"),
        }
    }
}