use chrono::prelude::*;
use chrono::Utc;
use std::path::Path;

use eyre::{eyre, Result};

use rusqlite::{params, Connection};
use rusqlite::{Params, Transaction};

use super::history::History;

pub trait Database {
    fn save(&mut self, h: &History) -> Result<()>;
    fn save_bulk(&mut self, h: &[History]) -> Result<()>;

    fn load(&self, id: &str) -> Result<History>;
    fn list(&self, max: Option<usize>, unique: bool) -> Result<Vec<History>>;
    fn range(&self, from: chrono::DateTime<Utc>, to: chrono::DateTime<Utc>)
        -> Result<Vec<History>>;

    fn query(&self, query: &str, params: impl Params) -> Result<Vec<History>>;
    fn update(&self, h: &History) -> Result<()>;
    fn history_count(&self) -> Result<i64>;

    fn first(&self) -> Result<History>;
    fn last(&self) -> Result<History>;
    fn before(&self, timestamp: chrono::DateTime<Utc>, count: i64) -> Result<Vec<History>>;

    fn prefix_search(&self, query: &str) -> Result<Vec<History>>;

    fn search(&self, cwd: Option<String>, exit: Option<i64>, query: &str) -> Result<Vec<History>>;
}

// Intended for use on a developer machine and not a sync server.
// TODO: implement IntoIterator
pub struct Sqlite {
    conn: Connection,
}

impl Sqlite {
    pub fn new(path: impl AsRef<Path>) -> Result<Self> {
        let path = path.as_ref();
        debug!("opening sqlite database at {:?}", path);

        let create = !path.exists();
        if create {
            if let Some(dir) = path.parent() {
                std::fs::create_dir_all(dir)?;
            }
        }

        let conn = Connection::open(path)?;

        Self::setup_db(&conn)?;

        Ok(Self { conn })
    }

    fn setup_db(conn: &Connection) -> Result<()> {
        debug!("running sqlite database setup");

        conn.execute(
            "create table if not exists history (
                id text primary key,
                timestamp integer not null,
                duration integer not null,
                exit integer not null,
                command text not null,
                cwd text not null,
                session text not null,
                hostname text not null,

                unique(timestamp, cwd, command)
            )",
            [],
        )?;

        conn.execute(
            "create table if not exists history_encrypted (
                id text primary key,
                data blob not null
            )",
            [],
        )?;

        conn.execute(
            "create index if not exists idx_history_timestamp on history(timestamp)",
            [],
        )?;

        conn.execute(
            "create index if not exists idx_history_command on history(command)",
            [],
        )?;

        Ok(())
    }

    fn save_raw(tx: &Transaction, h: &History) -> Result<()> {
        tx.execute(
            "insert or ignore into history (
            id,
            timestamp,
            duration,
            exit,
            command,
            cwd,
            session,
            hostname
        ) values (?1, ?2, ?3, ?4, ?5, ?6, ?7, ?8)",
            params![
                h.id,
                h.timestamp.timestamp_nanos(),
                h.duration,
                h.exit,
                h.command,
                h.cwd,
                h.session,
                h.hostname
            ],
        )?;

        Ok(())
    }
}

impl Database for Sqlite {
    fn save(&mut self, h: &History) -> Result<()> {
        debug!("saving history to sqlite");

        let tx = self.conn.transaction()?;
        Self::save_raw(&tx, h)?;
        tx.commit()?;

        Ok(())
    }

    fn save_bulk(&mut self, h: &[History]) -> Result<()> {
        debug!("saving history to sqlite");

        let tx = self.conn.transaction()?;
        for i in h {
            Self::save_raw(&tx, i)?
        }
        tx.commit()?;

        Ok(())
    }

    fn load(&self, id: &str) -> Result<History> {
        debug!("loading history item {}", id);

        let history = self.query(
            "select id, timestamp, duration, exit, command, cwd, session, hostname from history
                where id = ?1 limit 1",
            &[id],
        )?;

        if history.is_empty() {
            return Err(eyre!("could not find history with id {}", id));
        }

        let history = history[0].clone();

        Ok(history)
    }

    fn update(&self, h: &History) -> Result<()> {
        debug!("updating sqlite history");

        self.conn.execute(
            "update history
                set timestamp = ?2, duration = ?3, exit = ?4, command = ?5, cwd = ?6, session = ?7, hostname = ?8
                where id = ?1",
            params![h.id, h.timestamp.timestamp_nanos(), h.duration, h.exit, h.command, h.cwd, h.session, h.hostname],
        )?;

        Ok(())
    }

    // make a unique list, that only shows the *newest* version of things
    fn list(&self, max: Option<usize>, unique: bool) -> Result<Vec<History>> {
        debug!("listing history");

        // very likely vulnerable to SQL injection
        // however, this is client side, and only used by the client, on their
        // own data. They can just open the db file...
        // otherwise building the query is awkward
        let query = format!(
            "select * from history h
                {}
                order by timestamp desc
                {}",
            // inject the unique check
            if unique {
                "where timestamp = (
                        select max(timestamp) from history 
                        where h.command = history.command
                    )"
            } else {
                ""
            },
            // inject the limit
            if let Some(max) = max {
                format!("limit {}", max)
            } else {
                "".to_string()
            }
        );

        let history = self.query(query.as_str(), params![])?;

        Ok(history)
    }

    fn range(
        &self,
        from: chrono::DateTime<Utc>,
        to: chrono::DateTime<Utc>,
    ) -> Result<Vec<History>> {
        debug!("listing history from {:?} to {:?}", from, to);

        let mut stmt = self.conn.prepare(
            "SELECT * FROM history where timestamp >= ?1 and timestamp <= ?2 order by timestamp asc",
        )?;

        let history_iter = stmt.query_map(
            params![from.timestamp_nanos(), to.timestamp_nanos()],
            |row| history_from_sqlite_row(None, row),
        )?;

        Ok(history_iter.filter_map(Result::ok).collect())
    }

    fn first(&self) -> Result<History> {
        let mut stmt = self
            .conn
            .prepare("SELECT * FROM history order by timestamp asc limit 1")?;

        let history = stmt.query_row(params![], |row| history_from_sqlite_row(None, row))?;

        Ok(history)
    }

    fn last(&self) -> Result<History> {
        let mut stmt = self
            .conn
            .prepare("SELECT * FROM history where duration >= 0 order by timestamp desc limit 1")?;

        let history = stmt.query_row(params![], |row| history_from_sqlite_row(None, row))?;

        Ok(history)
    }

    fn before(&self, timestamp: chrono::DateTime<Utc>, count: i64) -> Result<Vec<History>> {
        let mut stmt = self
            .conn
            .prepare("SELECT * FROM history where timestamp < ? order by timestamp desc limit ?")?;

        let history_iter = stmt.query_map(params![timestamp.timestamp_nanos(), count], |row| {
            history_from_sqlite_row(None, row)
        })?;

        Ok(history_iter.filter_map(Result::ok).collect())
    }

    fn query(&self, query: &str, params: impl Params) -> Result<Vec<History>> {
        let mut stmt = self.conn.prepare(query)?;

        let history_iter = stmt.query_map(params, |row| history_from_sqlite_row(None, row))?;

        Ok(history_iter.filter_map(Result::ok).collect())
    }

    fn prefix_search(&self, query: &str) -> Result<Vec<History>> {
        let query = query.to_string().replace("*", "%"); // allow wildcard char

        self.query(
            "select * from history h 
                where command like ?1 || '%' 
                and timestamp = (
                    select max(timestamp) from history 
                    where h.command = history.command
                ) 
                order by timestamp desc limit 200",
            &[query.as_str()],
        )
    }

    fn history_count(&self) -> Result<i64> {
        let res: i64 =
            self.conn
                .query_row_and_then("select count(1) from history;", params![], |row| row.get(0))?;

        Ok(res)
    }

    fn search(&self, cwd: Option<String>, exit: Option<i64>, query: &str) -> Result<Vec<History>> {
        match (cwd, exit) {
            (Some(cwd), Some(exit)) => self.query(
                "select * from history 
                where command like ?1 || '%' 
                and cwd = ?2 
                and exit = ?3 
                order by timestamp asc limit 1000",
                &[query, cwd.as_str(), exit.to_string().as_str()],
            ),
            (Some(cwd), None) => self.query(
                "select * from history 
                where command like ?1 || '%' 
                and cwd = ?2 
                order by timestamp asc limit 1000",
                &[query, cwd.as_str()],
            ),
            (None, Some(exit)) => self.query(
                "select * from history 
            where command like ?1 || '%' 
            and exit = ?2 
            order by timestamp asc limit 1000",
                &[query, exit.to_string().as_str()],
            ),
            (None, None) => self.query(
                "select * from history 
            where command like ?1 || '%' 
            order by timestamp asc limit 1000",
                &[query],
            ),
        }
    }
}

fn history_from_sqlite_row(
    id: Option<String>,
    row: &rusqlite::Row,
) -> Result<History, rusqlite::Error> {
    let id = match id {
        Some(id) => id,
        None => row.get(0)?,
    };

    Ok(History {
        id,
        timestamp: Utc.timestamp_nanos(row.get(1)?),
        duration: row.get(2)?,
        exit: row.get(3)?,
        command: row.get(4)?,
        cwd: row.get(5)?,
        session: row.get(6)?,
        hostname: row.get(7)?,
    })
}