//! Series data.

use rusqlite::{Connection, Row, named_params};
use serde::Serialize;

use super::pagination::{HasPrevOrMoreError, Pagination, PaginationError, SortOrder};
use snafu::{ResultExt, Snafu};

/// Series in calibre.
#[derive(Debug, Clone, Serialize)]
pub struct Series {
    /// Id in database.
    pub id: u64,
    /// Series name.
    pub name: String,
    /// Series name for sorting.
    pub sort: String,
}

#[derive(Debug, Snafu)]
#[snafu(display("Failed to fetch multiple series."))]
pub struct MultiplSeriesError {
    source: PaginationError,
}

#[derive(Debug, Snafu)]
pub enum SeriesBooksError {
    #[snafu(display("Failed to prepare statement."))]
    PrepareSeriesBooks { source: rusqlite::Error },
    #[snafu(display("Failed to execute statement."))]
    ExecuteSeriesBooks { source: rusqlite::Error },
}

#[derive(Debug, Snafu)]
pub enum ScalarSeriesError {
    #[snafu(display("Failed to prepare statement."))]
    PrepareScalarSeries { source: rusqlite::Error },
    #[snafu(display("Failed to execute statement."))]
    ExecuteScalarSeries { source: rusqlite::Error },
}

#[derive(Debug, Snafu)]
#[snafu(display("Failed to check for previous series."))]
pub struct PreviousSeriesError {
    source: HasPrevOrMoreError,
}

#[derive(Debug, Snafu)]
#[snafu(display("Failed to check for more series."))]
pub struct MoreSeriesError {
    source: HasPrevOrMoreError,
}

impl Series {
    fn from_row(row: &Row<'_>) -> Result<Self, rusqlite::Error> {
        Ok(Self {
            id: row.get(0)?,
            name: row.get(1)?,
            sort: row.get(2)?,
        })
    }

    /// Fetch series data from calibre, starting at `cursor`, fetching up to an amount of `limit` and
    /// ordering by `sort_order`.
    pub fn multiple(
        conn: &Connection,
        limit: u64,
        cursor: Option<&str>,
        sort_order: &SortOrder,
    ) -> Result<Vec<Self>, MultiplSeriesError> {
        let pagination = Pagination::new("sort", cursor, limit, *sort_order);
        pagination
            .paginate(
                conn,
                "SELECT id, name, sort FROM series",
                &[],
                Self::from_row,
            )
            .context(MultiplSeriesSnafu)
    }

    /// Fetch a single series with id `id`.
    pub fn scalar_series(conn: &Connection, id: u64) -> Result<Self, ScalarSeriesError> {
        let mut stmt = conn
            .prepare("SELECT id, name, sort FROM series WHERE id = (:id)")
            .context(PrepareScalarSeriesSnafu)?;
        let params = named_params! { ":id": id };
        stmt.query_row(params, Self::from_row)
            .context(ExecuteScalarSeriesSnafu)
    }

    /// Get the series a book with id `id` is in, as well as the book's position within the series.
    pub fn book_series(
        conn: &Connection,
        book_id: u64,
    ) -> Result<Option<(Self, f64)>, SeriesBooksError> {
        let mut stmt = conn
            .prepare(
                "SELECT series.id, series.name, series.sort, books.series_index FROM series \
                INNER JOIN books_series_link ON series.id = books_series_link.series \
                INNER JOIN books ON books.id = books_series_link.book \
                WHERE books_series_link.book = (:id)",
            )
            .context(PrepareSeriesBooksSnafu)?;
        let params = named_params! { ":id": book_id };

        let from_row = |row: &Row<'_>| {
            let series = Self::from_row(row)?;
            let series_idx = row.get(3)?;
            Ok((series, series_idx))
        };

        match stmt.query_row(params, from_row) {
            Ok(series) => Ok(Some(series)),
            Err(rusqlite::Error::QueryReturnedNoRows) => Ok(None),
            Err(e) => Err(e).context(ExecuteSeriesBooksSnafu),
        }
    }

    /// Check if there are more series before the specified cursor.
    pub fn has_previous_series(
        conn: &Connection,
        sort_name: &str,
    ) -> Result<bool, PreviousSeriesError> {
        Pagination::has_prev_or_more(conn, "series", sort_name, &SortOrder::DESC)
            .context(PreviousSeriesSnafu)
    }

    /// Check if there are more series after the specified cursor.
    pub fn has_more_series(conn: &Connection, sort_name: &str) -> Result<bool, MoreSeriesError> {
        Pagination::has_prev_or_more(conn, "series", sort_name, &SortOrder::ASC)
            .context(MoreSeriesSnafu)
    }
}