use super::attrs::{self, Attr};
use super::blobref::BlobRef;
use super::object::Chunk;
use super::object::{Attrs, Object};
use crate::common::{json, sqlite};
use log::error;
use rusqlite::{params, Connection, Row};
use serde::{Deserialize, Serialize};
use std::path::PathBuf;
use time::OffsetDateTime;

#[derive(Serialize, Deserialize)]
pub struct Config {
    pub root: PathBuf,
}

const DB_NAME: &str = "index.sqlite3";
const SQL_INIT: &str = "
    create table objects (
        anchor text primary key,
        size integer not null,
        chunks text not null, -- JSON array
        created_at datetime not null,
        updated_at datetime not null,
        x_name text,
        x_group text,
        x_mime text,
        x_created_at text,
        x_updated_at text,
        x_deleted_at text,
        x_tags text,
        x_note text
    );
";

#[derive(Debug)]
pub enum Error {
    Internal(rusqlite::Error),
}

type Result<T> = std::result::Result<T, Error>;

pub struct Index {
    db: Connection,
}

impl Index {
    pub fn new(config: &Config) -> Result<Self> {
        let db = match Connection::open(config.root.join(DB_NAME)) {
            Ok(conn) => conn,
            Err(e) => {
                error!("Couldn't open connection to the database: {e:?}");
                return Err(Error::Internal(e));
            }
        };

        Ok(Self { db })
    }

    pub fn put(&self, anchor: &BlobRef, chunks: &[Chunk]) -> Result<()> {
        // Calculate the overall size
        let size: usize = chunks.iter().map(|c| c.size).sum();

        // Insert or update the object for `anchor`
        let query = "
            insert into objects (anchor, size, chunks, created_at, updated_at)
            values (?, ?, ?, ?, ?)
            on conflict do update set
                size = excluded.size,
                chunks = excluded.chunks,
                updated_at = excluded.updated_at
        ";

        let now = OffsetDateTime::now_utc();
        let mut stmt = self.db.prepare(query).map_err(Error::Internal)?;
        stmt.execute(params![anchor, size, json::serialize(chunks), now, now])
            .map_err(Error::Internal)?;

        Ok(())
    }

    pub fn set_attrs(&mut self, anchor: &BlobRef, attrs: &[Attr]) -> Result<()> {
        let now = OffsetDateTime::now_utc();
        let tx = self.db.transaction().map_err(Error::Internal)?;

        for attr in attrs {
            let query = format!(
                r#"update objects set "x_{}" = ? where anchor = ?"#,
                attrs::key(attr)
            );
            let mut stmt = tx.prepare(&query).map_err(Error::Internal)?;

            stmt.execute(params![attr, anchor])
                .map_err(Error::Internal)?;
        }

        {
            let mut stmt = tx
                .prepare("update objects set updated_at = ? where anchor = ?")
                .map_err(Error::Internal)?;
            stmt.execute(params![now, anchor])
                .map_err(Error::Internal)?;
        }

        tx.commit().map_err(Error::Internal)?;

        Ok(())
    }

    pub fn get(&self, anchor: &BlobRef) -> Result<Object> {
        let query = "select
                   anchor,
                   size,
                   chunks,
                   created_at,
                   updated_at,
                   x_name,
                   x_group,
                   x_mime,
                   x_created_at,
                   x_updated_at,
                   x_deleted_at,
                   x_tags,
                   x_note
               from objects
               where anchor = ?";

        sqlite::get(&self.db, query, (anchor,), |r| Object::try_from(r)).map_err(Error::Internal)
    }

    pub fn list(&self, limit: usize, offset: usize, filter: Option<Attr>) -> Result<Vec<Object>> {
        let where_clause = if let Some(ref filter) = filter {
            format!(r#""x_{}" = ?"#, attrs::key(filter))
        } else {
            "1=1".into()
        };

        let query = format!(
            r#"select
                   anchor,
                   size,
                   chunks,
                   created_at,
                   updated_at,
                   x_name,
                   x_group,
                   x_mime,
                   x_created_at,
                   x_updated_at,
                   x_deleted_at,
                   x_tags,
                   x_note
               from objects
               where {where_clause}
               order by rowid
               limit {limit} offset {offset}
            "#
        );

        if let Some(filter) = filter {
            sqlite::list(&self.db, &query, (filter,), |r| Object::try_from(r))
                .map_err(Error::Internal)
        } else {
            sqlite::list(&self.db, &query, (), |r| Object::try_from(r)).map_err(Error::Internal)
        }
    }
}
//
// impl Object {
//     fn new(blobref: BlobRef) -> Self {
//         Object {
//             blobref,
//             group: None,
//             is_group: false,
//             name: None,
//             kind: None,
//             size: None,
//             created_at: None,
//             updated_at: None,
//             deleted_at: None,
//             tags: Vec::new(),
//         }
//     }
//
//     pub fn get_name(&self) -> String {
//         self.name.clone().unwrap_or(self.blobref.to_string())
//     }
//
//     pub fn get_size(&self) -> u64 {
//         self.size.unwrap_or(0)
//     }
//
//     pub fn is_group(&self) -> bool {
//         self.is_group
//     }
//
//     fn apply_patch(&mut self, patch: Patch) {
//         for change in patch.changes {
//             self.apply_change(change);
//         }
//     }
//
//     fn apply_change(&mut self, change: Change) {
//         match change {
//             Change::MarkAsGroup => self.is_group = true,
//             Change::SetName { name } => self.name = Some(name),
//             Change::SetGroup { group } => self.group = Some(group),
//             Change::SetSize { size } => self.size = Some(size),
//             Change::SetCreatedAt { created_at } => self.created_at = Some(created_at),
//             Change::SetUpdatedAt { updated_at } => self.updated_at = Some(updated_at),
//             Change::SetDeletedAt { deleted_at } => self.deleted_at = Some(deleted_at),
//             Change::SetTags { tags } => self.tags = tags,
//         };
//     }
// }
//
// fn row_to_object(row: &Row) -> rusqlite::Result<Object> {
//     Ok(Object {
//         blobref: row.get(0)?,
//         group: row.get(1)?,
//         is_group: row.get(2)?,
//         name: row.get(3)?,
//         size: row.get(4)?,
//         kind: row.get(5)?,
//         created_at: row.get(6)?,
//         updated_at: row.get(7)?,
//         deleted_at: row.get(8)?,
//         tags: vec![],
//     })
// }

impl TryFrom<&Row<'_>> for Object {
    type Error = rusqlite::Error;

    fn try_from(row: &Row) -> std::result::Result<Object, Self::Error> {
        let chunks_string: Vec<u8> = row.get(2)?;
        let chunks = serde_json::from_slice::<Vec<Chunk>>(&chunks_string)
            .map_err(|_| rusqlite::Error::InvalidQuery)?;

        let attrs = Attrs {
            name: row.get(5)?,
            group: row.get(6)?,
            mime: row.get(7)?,
            created_at: row.get(8)?,
            updated_at: row.get(9)?,
            deleted_at: row.get(10)?,
            tags: Vec::new(),
            note: row.get(12)?,
        };

        Ok(Object {
            blobref: row.get(0)?,
            size: row.get(1)?,
            chunks,
            attrs,
            created_at: row.get(3)?,
            updated_at: row.get(4)?,
        })
    }
}