use crate::commands::WholeStreamCommand;
use crate::data::TaggedDictBuilder;
use crate::errors::ShellError;
use crate::prelude::*;

pub struct SplitBy;

#[derive(Deserialize)]
pub struct SplitByArgs {
    column_name: Tagged<String>,
}

impl WholeStreamCommand for SplitBy {
    fn name(&self) -> &str {
        "split-by"
    }

    fn signature(&self) -> Signature {
        Signature::build("split-by").required(
            "column_name",
            SyntaxShape::String,
            "the name of the column within the nested table to split by",
        )
    }

    fn usage(&self) -> &str {
        "Creates a new table with the data from the inner tables splitted by the column given."
    }

    fn run(
        &self,
        args: CommandArgs,
        registry: &CommandRegistry,
    ) -> Result<OutputStream, ShellError> {
        args.process(registry, split_by)?.run()
    }
}

pub fn split_by(
    SplitByArgs { column_name }: SplitByArgs,
    RunnableContext { input, name, .. }: RunnableContext,
) -> Result<OutputStream, ShellError> {
    let stream = async_stream! {
        let values: Vec<Tagged<Value>> = input.values.collect().await;

        if values.len() > 1 || values.is_empty() {
            yield Err(ShellError::labeled_error(
                    "Expected table from pipeline",
                    "requires a table input",
                    column_name.span()
                ))
        } else {
            match split(&column_name, &values[0], name) {
                Ok(split) => yield ReturnSuccess::value(split),
                Err(err) => yield Err(err),
            }
        }
    };

    Ok(stream.to_output_stream())
}

pub fn split(
    column_name: &Tagged<String>,
    value: &Tagged<Value>,
    tag: impl Into<Tag>,
) -> Result<Tagged<Value>, ShellError> {
    let origin_tag = tag.into();

    let mut splits = indexmap::IndexMap::new();

    match value {
        Tagged {
            item: Value::Row(group_sets),
            ..
        } => {
            for (group_key, group_value) in group_sets.entries.iter() {
                match *group_value {
                    Tagged {
                        item: Value::Table(ref dataset),
                        ..
                    } => {
                        let group = crate::commands::group_by::group(
                            &column_name,
                            dataset.to_vec(),
                            &origin_tag,
                        )?;

                        match group {
                            Tagged {
                                item: Value::Row(o),
                                ..
                            } => {
                                for (split_label, subset) in o.entries.into_iter() {
                                    match subset {
                                        Tagged {
                                            item: Value::Table(subset),
                                            tag,
                                        } => {
                                            let s = splits
                                                .entry(split_label.clone())
                                                .or_insert(indexmap::IndexMap::new());
                                            s.insert(
                                                group_key.clone(),
                                                Value::table(&subset).tagged(tag),
                                            );
                                        }
                                        other => {
                                            return Err(ShellError::type_error(
                                                "a table value",
                                                other.tagged_type_name(),
                                            ))
                                        }
                                    }
                                }
                            }
                            _ => {
                                return Err(ShellError::type_error(
                                    "a table value",
                                    group.tagged_type_name(),
                                ))
                            }
                        }
                    }
                    ref other => {
                        return Err(ShellError::type_error(
                            "a table value",
                            other.tagged_type_name(),
                        ))
                    }
                }
            }
        }
        _ => {
            return Err(ShellError::type_error(
                "a table value",
                value.tagged_type_name(),
            ))
        }
    }

    let mut out = TaggedDictBuilder::new(&origin_tag);

    for (k, v) in splits.into_iter() {
        out.insert(k, Value::row(v));
    }

    Ok(out.into_tagged_value())
}
#[cfg(test)]
mod tests {

    use crate::commands::split_by::split;
    use crate::data::meta::*;
    use crate::Value;
    use indexmap::IndexMap;

    fn string(input: impl Into<String>) -> Tagged<Value> {
        Value::string(input.into()).tagged_unknown()
    }

    fn row(entries: IndexMap<String, Tagged<Value>>) -> Tagged<Value> {
        Value::row(entries).tagged_unknown()
    }

    fn table(list: &Vec<Tagged<Value>>) -> Tagged<Value> {
        Value::table(list).tagged_unknown()
    }

    #[test]
    fn splits_inner_tables_by_key() {
        let for_key = String::from("country").tagged_unknown();

        let nu_releases = row(indexmap! {
            "August 23-2019".into() =>  table(&vec![
                    row(indexmap!{"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("August 23-2019")}),
                    row(indexmap!{"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("August 23-2019")}),
                    row(indexmap!{"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("August 23-2019")})
            ]),
            "Sept 24-2019".into() =>  table(&vec![
                    row(indexmap!{"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("Sept 24-2019")}),
                    row(indexmap!{"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("Sept 24-2019")}),
                    row(indexmap!{"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("Sept 24-2019")})
            ]),
            "October 10-2019".into() =>  table(&vec![
                    row(indexmap!{"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("October 10-2019")}),
                    row(indexmap!{"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("October 10-2019")}),
                    row(indexmap!{"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("October 10-2019")})
            ])
        });

        assert_eq!(
            split(&for_key, &nu_releases, Tag::unknown()).unwrap(),
            Value::row(indexmap! {
                "EC".into() => row(indexmap! {
                    "August 23-2019".into() => table(&vec![
                        row(indexmap!{"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("August 23-2019")})
                    ]),
                    "Sept 24-2019".into() => table(&vec![
                        row(indexmap!{"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("Sept 24-2019")})
                    ]),
                    "October 10-2019".into() => table(&vec![
                        row(indexmap!{"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("October 10-2019")})
                    ])
                }),
                "NZ".into() => row(indexmap! {
                    "August 23-2019".into() => table(&vec![
                        row(indexmap!{"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("August 23-2019")})
                    ]),
                    "Sept 24-2019".into() => table(&vec![
                        row(indexmap!{"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("Sept 24-2019")})
                    ]),
                    "October 10-2019".into() => table(&vec![
                        row(indexmap!{"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("October 10-2019")})
                    ])
                }),
                "US".into() => row(indexmap! {
                    "August 23-2019".into() => table(&vec![
                        row(indexmap!{"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("August 23-2019")})
                    ]),
                    "Sept 24-2019".into() => table(&vec![
                        row(indexmap!{"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("Sept 24-2019")})
                    ]),
                    "October 10-2019".into() => table(&vec![
                        row(indexmap!{"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("October 10-2019")})
                    ])
                })
            }).tagged_unknown()
        );
    }

    #[test]
    fn errors_if_key_within_some_inner_table_is_missing() {
        let for_key = String::from("country").tagged_unknown();

        let nu_releases = row(indexmap! {
            "August 23-2019".into() =>  table(&vec![
                    row(indexmap!{"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("August 23-2019")}),
                    row(indexmap!{"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("August 23-2019")}),
                    row(indexmap!{"name".into() => string("YK"),  "country".into() => string("US"), "date".into() => string("August 23-2019")})
            ]),
            "Sept 24-2019".into() =>  table(&vec![
                    row(indexmap!{"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("Sept 24-2019")}),
                    row(indexmap!{"name".into() => Value::string("JT").tagged(Tag::from(Span::new(5,10))), "date".into() => string("Sept 24-2019")}),
                    row(indexmap!{"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("Sept 24-2019")})
            ]),
            "October 10-2019".into() =>  table(&vec![
                    row(indexmap!{"name".into() => string("AR"), "country".into() => string("EC"), "date".into() => string("October 10-2019")}),
                    row(indexmap!{"name".into() => string("JT"), "country".into() => string("NZ"), "date".into() => string("October 10-2019")}),
                    row(indexmap!{"name".into() => string("YK"), "country".into() => string("US"), "date".into() => string("October 10-2019")})
            ])
        });

        assert!(split(&for_key, &nu_releases, Tag::from(Span::new(5, 10))).is_err());
    }
}