use super::*;
use anyhow::Result;
use lazy_static::lazy_static;
use log::*;
use rusqlite::types::ValueRef;
use rusqlite::*;
use std::convert::TryInto;
use writing::{WritingFileAdapter, WritingFileAdapterTrait};

static EXTENSIONS: &[&str] = &["db", "db3", "sqlite", "sqlite3"];

lazy_static! {
    static ref METADATA: AdapterMeta = AdapterMeta {
        name: "sqlite".to_owned(),
        version: 1,
        description:
            "Uses sqlite bindings to convert sqlite databases into a simple plain text format"
                .to_owned(),
        recurses: false, // set to true if we decide to make sqlite blobs searchable (gz blob in db is kinda common I think)
        fast_matchers: EXTENSIONS
            .iter()
            .map(|s| FastMatcher::FileExtension(s.to_string()))
            .collect(),
        slow_matchers: Some(vec![SlowMatcher::MimeType(
            "application/x-sqlite3".to_owned()
        )]),
        disabled_by_default: false
    };
}

#[derive(Default, Clone)]
pub struct SqliteAdapter;

impl SqliteAdapter {
    pub fn new() -> WritingFileAdapter {
        WritingFileAdapter::new(Box::new(SqliteAdapter {}))
    }
}
impl GetMetadata for SqliteAdapter {
    fn metadata(&self) -> &AdapterMeta {
        &METADATA
    }
}

fn format_blob(b: ValueRef) -> String {
    use ValueRef::*;
    match b {
        Null => "NULL".to_owned(),
        Integer(i) => format!("{}", i),
        Real(i) => format!("{}", i),
        Text(i) => format!("'{}'", String::from_utf8_lossy(i).replace("'", "''")),
        Blob(b) => format!(
            "[blob {}B]",
            size_format::SizeFormatterSI::new(
                // can't be larger than 2GB anyways
                b.len().try_into().unwrap()
            )
        ),
    }
}

impl WritingFileAdapterTrait for SqliteAdapter {
    fn adapt_write(
        &self,
        ai: AdaptInfo,
        _detection_reason: &SlowMatcher,
        oup: &mut dyn Write,
    ) -> Result<()> {
        let AdaptInfo {
            is_real_file,
            filepath_hint,
            line_prefix,
            ..
        } = ai;
        if !is_real_file {
            // db is in an archive
            // todo: read to memory and then use that blob if size < max
            writeln!(oup, "{}[rga: skipping sqlite in archive]", line_prefix,)?;
            return Ok(());
        }
        let inp_fname = filepath_hint;

        let conn = Connection::open_with_flags(inp_fname, OpenFlags::SQLITE_OPEN_READ_ONLY)?;
        let tables: Vec<String> = conn
            .prepare("select name from sqlite_master where type='table'")?
            .query_map(NO_PARAMS, |r| r.get::<_, String>(0))?
            .filter_map(|e| e.ok())
            .collect();
        debug!("db has {} tables", tables.len());
        for table in tables {
            // can't use query param at that position
            let mut sel = conn.prepare(&format!(
                "select * from {}",
                rusqlite::vtab::escape_double_quote(&table)
            ))?;
            let mut z = sel.query(NO_PARAMS)?;
            let col_names: Vec<String> = z
                .column_names()
                .ok_or_else(|| format_err!("no column names"))?
                .into_iter()
                .map(|e| e.to_owned())
                .collect();
            // writeln!(oup, "{}: {}", table, cols.join(", "))?;

            // kind of shitty (lossy) output. maybe output real csv or something?
            while let Some(row) = z.next()? {
                writeln!(
                    oup,
                    "{}{}: {}",
                    line_prefix,
                    table,
                    col_names
                        .iter()
                        .enumerate()
                        .map(|(i, e)| format!("{}={}", e, format_blob(row.get_raw(i))))
                        .collect::<Vec<String>>()
                        .join(", ")
                )?;
            }
        }
        Ok(())
    }
}

#[cfg(test)]
mod test {
    use super::*;
    use crate::{test_utils::*};
    use std::{fs::File};

    #[test]
    fn simple() -> Result<()> {
        let adapter: Box<dyn FileAdapter> = Box::new(SqliteAdapter::new());
        let fname = test_data_dir().join("hello.sqlite3");
        let rd = File::open(&fname)?;
        let (a, d) = simple_adapt_info(&fname, Box::new(rd));
        let mut res = adapter.adapt(a, &d)?;

        let mut buf = Vec::new();
        res.read_to_end(&mut buf)?;

        assert_eq!(
            String::from_utf8(buf)?,
            "PREFIX:tbl: greeting='hello', from='sqlite database!'\nPREFIX:tbl2: x=123, y=456.789\n",
        );

        Ok(())
    }
}