// Copyright (C) 2024 Riften Labs AS
//
// This software is licensed under the GNU Affero General Public License (AGPL), version 3.0 or later.
// A copy of the license can be found in the LICENSE file or at https://www.gnu.org/licenses/agpl-3.0.html

use crate::bcmr::parsedbcmr::{FileMeta, ParsedBCMR, Token, Uris, SOURCE_ON_CHAIN};
use anyhow::*;
use bitcoin_hashes::hex::{FromHex, ToHex};
use bitcoincash::{BlockHash, TokenID, Txid};
use log::info;
use riftenlabs_defi::chainutil::OutPointHash;
use rusqlite::{params, Connection};

// Flag BCMR download as give up after this many attempts.
const MAX_DOWNLOAD_ATTEMPTS: usize = 100;

// BCMR auth chain entry, matches auth_chain_entry table
#[allow(dead_code)]
pub struct AuthChainEntry {
    pub utxo: OutPointHash,
    pub txid: Txid,
    pub token_id: TokenID,
    pub height: usize,
    pub bcmr_data: Option<Vec<u8>>,
}

pub fn prepare_tables(conn: &Connection) {
    conn.execute(
        "CREATE TABLE auth_chain_entry (
            utxo TEXT PRIMARY KEY,
            blockhash TEXT NOT NULL,
            txid TEXT NOT NULL,
            token_id TEXT NOT NULL,
            height INT NOT NULL,
            bcmr_data TEXT
        )",
        [],
    )
    .expect("failed to create auth_chain_entry table");

    conn.execute(
        "CREATE TABLE bcmr_data (
            utxo TEXT PRIMARY KEY,
            symbol TEXT NOT NULL,
            decimals INT NOT NULL,
            name TEXT NOT NULL,
            description TEXT NOT NULL,
            icon TEXT NOT NULL,
            web TEXT NOT NULL,
            expected_hash TEXT NOT NULL,
            actual_hash TEXT NOT NULL,
            FOREIGN KEY (utxo) REFERENCES auth_chain_entry(utxo) ON DELETE CASCADE
        )",
        [],
    )
    .expect("failed to create bcmr_data table");

    conn.execute(
        "CREATE TABLE bcmr_failure (
            utxo TEXT PRIMARY KEY,
            last_attempt INT NOT NULL,
            attempts INT NOT NULL,
            error_message TEXT,
            give_up BOOLEAN,
            FOREIGN KEY (utxo) REFERENCES auth_chain_entry(utxo) ON DELETE CASCADE
        )",
        [],
    )
    .expect("failed to create bcmr_failure table");

    conn.execute(
        "
        CREATE TABLE bcmr_well_known (
            source TEXT NOT NULL,
            symbol TEXT NOT NULL,
            token_id TEXT NOT NULL,
            decimals INT NOT NULL,
            name TEXT NOT NULL,
            description TEXT NOT NULL,
            icon TEXT NOT NULL,
            web TEXT NOT NULL,
            PRIMARY KEY (source, token_id)
        )
    ",
        [],
    )
    .unwrap();

    // Create index for efficient token BCMR lookups
    conn.execute(
        "CREATE INDEX IF NOT EXISTS idx_auth_chain_token_bcmr_height
         ON auth_chain_entry(token_id, height DESC)
         WHERE bcmr_data IS NOT NULL",
        [],
    )
    .expect("failed to create index for token BCMR lookups");
}

pub fn delete_entries_for_well_known(tx: &Connection, source: &str) -> Result<()> {
    let mut stmt = tx.prepare("DELETE FROM bcmr_well_known WHERE source = ?")?;
    stmt.execute(params![source])?;
    Ok(())
}

pub fn delete_entries_for_block(tx: &Connection, blockhash: &BlockHash) -> Result<bool> {
    let mut stmt = tx.prepare("DELETE FROM auth_chain_entry WHERE blockhash = ?")?;
    let rows_deleted = stmt.execute(params![blockhash.to_hex()])?;

    Ok(rows_deleted != 0)
}

/// Add or update config entry
pub fn insert_authheader(
    conn: &Connection,
    utxo: &OutPointHash,
    blockhash: &BlockHash,
    txid: &Txid,
    token_id: &TokenID,
    height: usize,
    bcmr_data: Option<Vec<u8>>,
) -> Result<()> {
    let mut stmt = conn
        .prepare("INSERT OR REPLACE INTO auth_chain_entry (utxo, blockhash, txid, token_id, height, bcmr_data) VALUES (?, ?, ?, ?, ?, ?)")?;
    stmt.execute(params![
        utxo.to_hex(),
        blockhash.to_hex(),
        txid.to_hex(),
        token_id.to_hex(),
        height,
        bcmr_data.map(|bcmr| bcmr.to_hex())
    ])?;
    Ok(())
}

/// Get config entry
#[allow(dead_code)]
pub fn get_authheader(conn: &Connection, utxo: &OutPointHash) -> Result<Option<AuthChainEntry>> {
    let mut stmt = conn
        .prepare("SELECT token_id, txid, height, bcmr_data FROM auth_chain_entry WHERE utxo = ?")?;
    let mut row = stmt.query([utxo.to_hex()])?;

    let auth_header = row.next()?;

    if let Some(header) = auth_header {
        let token_hex: String = header.get(0)?;
        let txid_hex: String = header.get(1)?;
        let height = header.get(2)?;
        let bcmr_data_hex: Option<String> = header.get(3)?;
        let bcmr_data = if let Some(data) = bcmr_data_hex {
            Some(hex::decode(data).context("failed to decode bcmr data")?)
        } else {
            None
        };

        Ok(Some(AuthChainEntry {
            utxo: *utxo,
            token_id: TokenID::from_hex(&token_hex).context("failed to decode token hex")?,
            txid: Txid::from_hex(&txid_hex).context("failed to decode txid")?,
            height,
            bcmr_data,
        }))
    } else {
        Ok(None)
    }
}

pub fn get_matching_autheaders<'a>(
    conn: &Connection,
    keys: impl Iterator<Item = &'a OutPointHash>,
) -> Result<Vec<AuthChainEntry>> {
    // To not exceed SQL query length; we chunk the queries into entries of this size.
    let chunk_size = 10000;

    let keys: Vec<String> = keys.map(|utxo| utxo.to_hex()).collect();
    let mut matches: Vec<AuthChainEntry> = Vec::new();

    // Process in chunks
    for chunk in keys.chunks(chunk_size) {
        let in_clause = chunk.join("','");
        let sql = format!(
            "SELECT token_id, txid, height, bcmr_data, utxo FROM auth_chain_entry WHERE utxo IN ('{in_clause}')"
        );

        let mut stmt = conn.prepare(&sql)?;

        let mut rows = stmt.query([])?;

        while let Some(header) = rows.next()? {
            let token_hex: String = header.get(0)?;
            let txid_hex: String = header.get(1)?;
            let height = header.get(2)?;
            let bcmr_data_hex: Option<String> = header.get(3)?;
            let bcmr_data = if let Some(data) = bcmr_data_hex {
                Some(hex::decode(&data).context("failed to decode bcmr data")?)
            } else {
                None
            };

            let utxo_hex: String = header.get(4)?;
            let utxo = OutPointHash::from_hex(&utxo_hex)?;

            matches.push(AuthChainEntry {
                utxo,
                token_id: TokenID::from_hex(&token_hex).context("failed to decode token hex")?,
                txid: Txid::from_hex(&txid_hex).context("failed to decode txid")?,
                height,
                bcmr_data,
            })
        }
    }

    Ok(matches)
}

pub fn get_entries_missing_bcmr_download(conn: &Connection) -> Result<Vec<AuthChainEntry>> {
    let sql = "WITH MaxHeight AS (
        -- CTE to find the highest height for each token_id where bcmr_data is not null initially
        SELECT
            token_id,
            MAX(height) AS max_height
        FROM
            auth_chain_entry
        WHERE
            bcmr_data IS NOT NULL
        GROUP BY
            token_id
    )
    SELECT
        ace.token_id, ace.txid, ace.height, ace.bcmr_data, ace.utxo
    FROM
        auth_chain_entry AS ace
        -- Join with MaxHeight to get the maximum height entries
        JOIN MaxHeight mh ON ace.token_id = mh.token_id AND ace.height = mh.max_height
        -- Exclude entries that have a corresponding entry in bcmr_data
        LEFT JOIN bcmr_data bd ON ace.utxo = bd.utxo
        -- Exclude entries that have a corresponding failure entry where give_up = true or last attempt was less than 1800 seconds ago
        LEFT JOIN bcmr_failure bf ON ace.utxo = bf.utxo AND (bf.give_up = 1 OR (strftime('%s', 'now') - bf.last_attempt) < 1800)
    WHERE
        -- Ensure no matching entries in bcmr_data and only include bcmr_failure when filtered conditions aren't met
        bd.utxo IS NULL AND
        bf.utxo IS NULL;
    ";

    let mut stmt = conn.prepare(sql)?;

    let mut rows = stmt.query([])?;

    let mut matches: Vec<AuthChainEntry> = Vec::new();

    while let Some(header) = rows.next()? {
        let token_hex: String = header.get(0)?;
        let txid_hex: String = header.get(1)?;
        let height = header.get(2)?;
        let bcmr_data_hex: Option<String> = header.get(3)?;
        let bcmr_data = if let Some(data) = bcmr_data_hex {
            Some(hex::decode(&data).context("failed to decode bcmr data")?)
        } else {
            None
        };

        let utxo_hex: String = header.get(4)?;
        let utxo = OutPointHash::from_hex(&utxo_hex)?;

        matches.push(AuthChainEntry {
            utxo,
            token_id: TokenID::from_hex(&token_hex).context("failed to decode token hex")?,
            txid: Txid::from_hex(&txid_hex).context("failed to decode txid")?,
            height,
            bcmr_data,
        })
    }

    Ok(matches)
}

pub fn insert_bcmr_data(
    conn: &rusqlite::Connection,
    utxo: &OutPointHash,
    bcmr: &ParsedBCMR,
) -> Result<()> {
    let sql = "INSERT OR REPLACE INTO bcmr_data (utxo, symbol, decimals, name, description, icon, web, expected_hash, actual_hash)
               VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)";

    info!("Trying to insert {}", utxo.to_hex());
    let empty_string: String = "".to_owned();
    conn.execute(
        sql,
        rusqlite::params![
            &utxo.to_hex(),
            &bcmr.token.symbol,
            bcmr.token.decimals,
            &bcmr.name,
            &bcmr.description,
            &bcmr.uris.icon.as_ref().unwrap_or(&empty_string),
            &bcmr.uris.web.as_ref().unwrap_or(&empty_string),
            &bcmr.filemeta.expected_hash,
            &bcmr.filemeta.actual_hash
        ],
    )?;
    Ok(())
}

pub fn insert_well_known_bcmr(
    conn: &rusqlite::Connection,
    source: &str,
    bcmr: &ParsedBCMR,
) -> Result<()> {
    let sql = "INSERT OR REPLACE INTO bcmr_well_known (source, symbol, token_id, decimals, name, description, icon, web)
               VALUES (?, ?, ?, ?, ?, ?, ?, ?)";

    let empty_string: String = "".to_owned();

    conn.execute(
        sql,
        rusqlite::params![
            source,
            bcmr.token.symbol,
            bcmr.token.category,
            bcmr.token.decimals,
            &bcmr.name,
            &bcmr.description,
            &bcmr.uris.icon.as_ref().unwrap_or(&empty_string),
            &bcmr.uris.web.as_ref().unwrap_or(&empty_string)
        ],
    )?;

    Ok(())
}

pub fn update_bcmr_failure(
    conn: &Connection,
    utxo: &OutPointHash,
    error_message: &str,
    give_up: bool,
) -> Result<()> {
    let sql = format!(
        "
    INSERT INTO bcmr_failure (utxo, last_attempt, attempts, error_message, give_up)
    VALUES (?1, strftime('%s', 'now'), 1, ?2, ?3)
    ON CONFLICT(utxo) DO UPDATE SET
        last_attempt = excluded.last_attempt,
        attempts = bcmr_failure.attempts + 1,
        error_message = excluded.error_message,
        give_up = CASE
            WHEN bcmr_failure.attempts + 1 > {MAX_DOWNLOAD_ATTEMPTS} THEN true
            ELSE excluded.give_up
        END"
    );
    conn.execute(&sql, params![&utxo.to_hex(), error_message, give_up])?;
    Ok(())
}

pub fn get_token_bcmr(conn: &Connection, token_hex: &str) -> Result<Option<ParsedBCMR>> {
    let sql = "SELECT
                b.symbol, b.decimals, b.name, b.description, b.icon, b.web, b.actual_hash, b.expected_hash
            FROM auth_chain_entry a
            JOIN bcmr_data b ON a.utxo = b.utxo
            WHERE a.token_id = ?
            AND a.bcmr_data IS NOT NULL
            ORDER BY a.height DESC
            LIMIT 1";

    let mut stmt = conn.prepare(sql)?;
    let mut row = stmt.query([token_hex])?;

    if let Some(r) = row.next()? {
        let symbol: String = r.get(0)?;
        let decimals: usize = r.get(1)?;
        let name = r.get(2)?;
        let description = r.get(3)?;
        let icon: String = r.get(4)?;
        let web: String = r.get(5)?;
        let actual_hash: String = r.get(6)?;
        let expected_hash: String = r.get(7)?;

        Ok(Some(ParsedBCMR {
            name,
            description,
            token: Token {
                category: token_hex.to_owned(),
                symbol,
                decimals,
            },
            uris: Uris {
                web: if web.is_empty() { None } else { Some(web) },
                icon: if icon.is_empty() { None } else { Some(icon) },
            },
            filemeta: FileMeta {
                expected_hash: Some(expected_hash),
                actual_hash: Some(actual_hash),
                source: SOURCE_ON_CHAIN.into(),
            },
        }))
    } else {
        Ok(None)
    }
}

pub fn get_well_known_bcmr(conn: &Connection, token_hex: &str) -> Result<Vec<ParsedBCMR>> {
    let sql = "SELECT
                source, symbol, decimals, name, description, icon, web
            FROM bcmr_well_known
            WHERE token_id = ?";

    let mut stmt = conn.prepare(sql)?;
    let mut row = stmt.query([token_hex])?;

    let mut entries: Vec<ParsedBCMR> = Vec::default();

    while let Some(r) = row.next()? {
        let source: String = r.get(0)?;
        let symbol: String = r.get(1)?;
        let decimals: usize = r.get(2)?;
        let name = r.get(3)?;
        let description = r.get(4)?;
        let icon: String = r.get(5)?;
        let web: String = r.get(6)?;

        entries.push(ParsedBCMR {
            name,
            description,
            token: Token {
                category: token_hex.to_owned(),
                symbol,
                decimals,
            },
            uris: Uris {
                web: if web.is_empty() { None } else { Some(web) },
                icon: if icon.is_empty() { None } else { Some(icon) },
            },
            filemeta: FileMeta {
                expected_hash: None,
                actual_hash: None,
                source,
            },
        })
    }

    Ok(entries)
}