use syn::parse::{ParseStream, Result};

#[cfg(all(not(feature = "without-deprecated"), feature = "with-deprecated"))]
mod belongs_to;
#[cfg(all(not(feature = "without-deprecated"), feature = "with-deprecated"))]
mod changeset_options;
#[cfg(all(not(feature = "without-deprecated"), feature = "with-deprecated"))]
mod postgres_type;
#[cfg(all(not(feature = "without-deprecated"), feature = "with-deprecated"))]
mod primary_key;
#[cfg(all(not(feature = "without-deprecated"), feature = "with-deprecated"))]
mod utils;

pub trait ParseDeprecated: Sized {
    fn parse_deprecated(input: ParseStream) -> Result<Option<Self>>;
}

#[cfg(any(feature = "without-deprecated", not(feature = "with-deprecated")))]
mod not_deprecated {
    use super::{ParseDeprecated, ParseStream, Result};
    use crate::attrs::{FieldAttr, StructAttr};

    impl ParseDeprecated for StructAttr {
        fn parse_deprecated(_input: ParseStream) -> Result<Option<Self>> {
            unimplemented!()
        }
    }

    impl ParseDeprecated for FieldAttr {
        fn parse_deprecated(_input: ParseStream) -> Result<Option<Self>> {
            unimplemented!()
        }
    }
}

#[cfg(all(not(feature = "without-deprecated"), feature = "with-deprecated"))]
mod impl_deprecated {
    use super::{ParseDeprecated, ParseStream, Result};
    use crate::attrs::{FieldAttr, StructAttr};
    use crate::deprecated::belongs_to::parse_belongs_to;
    use crate::deprecated::changeset_options::parse_changeset_options;
    use crate::deprecated::postgres_type::parse_postgres_type;
    use crate::deprecated::primary_key::parse_primary_key;
    use crate::deprecated::utils::parse_eq_and_lit_str;
    use crate::parsers::{MysqlType, PostgresType, SqliteType};
    use crate::util::{
        COLUMN_NAME_NOTE, MYSQL_TYPE_NOTE, SQLITE_TYPE_NOTE, SQL_TYPE_NOTE, TABLE_NAME_NOTE,
    };
    use proc_macro2::Span;
    use syn::Ident;

    macro_rules! warn {
        ($ident: expr, $help: expr) => {
            warn(
                $ident.span(),
                &format!("#[{}] attribute form is deprecated", $ident),
                $help,
            );
        };
    }

    impl ParseDeprecated for StructAttr {
        fn parse_deprecated(input: ParseStream) -> Result<Option<Self>> {
            let name: Ident = input.parse()?;
            let name_str = name.to_string();

            match &*name_str {
                "table_name" => {
                    let lit_str = parse_eq_and_lit_str(name.clone(), input, TABLE_NAME_NOTE)?;
                    warn!(
                        name,
                        &format!("use `#[diesel(table_name = {})]` instead", lit_str.value())
                    );
                    Ok(Some(StructAttr::TableName(name, lit_str.parse()?)))
                }
                "changeset_options" => {
                    let (ident, value) = parse_changeset_options(name.clone(), input)?;
                    warn!(
                        name,
                        &format!(
                            "use `#[diesel(treat_none_as_null = {})]` instead",
                            value.value
                        )
                    );
                    Ok(Some(StructAttr::TreatNoneAsNull(ident, value)))
                }
                "sql_type" => {
                    let lit_str = parse_eq_and_lit_str(name.clone(), input, SQL_TYPE_NOTE)?;
                    warn!(
                        name,
                        &format!("use `#[diesel(sql_type = {})]` instead", lit_str.value())
                    );
                    Ok(Some(StructAttr::SqlType(name, lit_str.parse()?)))
                }
                "primary_key" => {
                    let keys = parse_primary_key(name.clone(), input)?;
                    let hint = keys
                        .iter()
                        .map(|i| i.to_string())
                        .collect::<Vec<_>>()
                        .join(", ");
                    warn!(
                        name,
                        &format!("use `#[diesel(primary_key({hint}))]` instead")
                    );
                    Ok(Some(StructAttr::PrimaryKey(name, keys)))
                }
                "belongs_to" => {
                    let belongs_to = parse_belongs_to(name.clone(), input)?;
                    let parent = belongs_to
                        .parent
                        .path
                        .segments
                        .iter()
                        .map(|s| s.ident.to_string())
                        .collect::<Vec<_>>()
                        .join("::");
                    if let Some(ref key) = belongs_to.foreign_key {
                        warn!(
                            name,
                            &format!(
                                "use `#[diesel(belongs_to({parent}, foreign_key = {key}))]` instead"
                            )
                        );
                    } else {
                        warn!(
                            name,
                            &format!("use `#[diesel(belongs_to({parent}))]` instead")
                        );
                    }
                    Ok(Some(StructAttr::BelongsTo(name, belongs_to)))
                }
                "sqlite_type" => {
                    let name_value = parse_eq_and_lit_str(name.clone(), input, SQLITE_TYPE_NOTE)?;
                    warn!(
                        name,
                        &format!(
                            "use `#[diesel(sqlite_type(name = \"{}\"))]` instead",
                            name_value.value()
                        )
                    );
                    Ok(Some(StructAttr::SqliteType(
                        name,
                        SqliteType { name: name_value },
                    )))
                }
                "mysql_type" => {
                    let name_value = parse_eq_and_lit_str(name.clone(), input, MYSQL_TYPE_NOTE)?;
                    warn!(
                        name,
                        &format!(
                            "use `#[diesel(mysql_type(name = \"{}\"))]` instead",
                            name_value.value()
                        )
                    );
                    Ok(Some(StructAttr::MysqlType(
                        name,
                        MysqlType { name: name_value },
                    )))
                }
                "postgres" => {
                    let pg_type = parse_postgres_type(name.clone(), input)?;
                    let msg = match &pg_type {
                        PostgresType::Fixed(oid, array_oid) => format!(
                            "use `#[diesel(postgres_type(oid = {}, array_oid = {}))]` instead",
                            oid.base10_parse::<u32>()?,
                            array_oid.base10_parse::<u32>()?
                        ),
                        PostgresType::Lookup(name, Some(schema)) => format!(
                        "use `#[diesel(postgres_type(name = \"{}\", schema = \"{}\"))]` instead",
                        name.value(),
                        schema.value()
                    ),
                        PostgresType::Lookup(name, None) => format!(
                            "use `#[diesel(postgres_type(name = \"{}\"))]` instead",
                            name.value(),
                        ),
                    };

                    warn!(name, &msg);
                    Ok(Some(StructAttr::PostgresType(name, pg_type)))
                }
                _ => Ok(None),
            }
        }
    }

    #[cfg(all(not(feature = "without-deprecated"), feature = "with-deprecated"))]
    impl ParseDeprecated for FieldAttr {
        fn parse_deprecated(input: ParseStream) -> Result<Option<Self>> {
            let name: Ident = input.parse()?;
            let name_str = name.to_string();

            match &*name_str {
                "column_name" => {
                    let lit_str = parse_eq_and_lit_str(name.clone(), input, COLUMN_NAME_NOTE)?;
                    warn!(
                        name,
                        &format!("use `#[diesel(column_name = {})]` instead", lit_str.value())
                    );
                    Ok(Some(FieldAttr::ColumnName(name, lit_str.parse()?)))
                }
                "sql_type" => {
                    let lit_str = parse_eq_and_lit_str(name.clone(), input, SQL_TYPE_NOTE)?;
                    warn!(
                        name,
                        &format!("use `#[diesel(sql_type = {})]` instead", lit_str.value())
                    );
                    Ok(Some(FieldAttr::SqlType(name, lit_str.parse()?)))
                }

                _ => Ok(None),
            }
        }
    }

    #[cfg(feature = "nightly")]
    fn warn(span: Span, message: &str, help: &str) {
        proc_macro::Diagnostic::spanned(span.unwrap(), proc_macro::Level::Warning, message)
            .help(help)
            .emit()
    }

    #[cfg(not(feature = "nightly"))]
    fn warn(_span: Span, message: &str, help: &str) {
        eprintln!("warning: {message}\n  = help: {help}\n");
    }
}