use crate::errors::{LimboError, Result};
use jni::objects::{JByteArray, JObject};
use jni::sys::{jint, jlong};
use jni::JNIEnv;
use limbo_core::Database;
use std::sync::Arc;

const ERROR_CODE_ETC: i32 = 9999;

#[no_mangle]
#[allow(clippy::arc_with_non_send_sync)]
pub extern "system" fn Java_org_github_tursodatabase_core_LimboDB_openUtf8<'local>(
    mut env: JNIEnv<'local>,
    obj: JObject<'local>,
    file_name_byte_arr: JByteArray<'local>,
    _open_flags: jint,
) -> jlong {
    let io = match limbo_core::PlatformIO::new() {
        Ok(io) => Arc::new(io),
        Err(e) => {
            set_err_msg_and_throw_exception(&mut env, obj, ERROR_CODE_ETC, e.to_string());
            return -1;
        }
    };

    let path = match env
        .convert_byte_array(file_name_byte_arr)
        .map_err(|e| e.to_string())
    {
        Ok(bytes) => match String::from_utf8(bytes) {
            Ok(s) => s,
            Err(e) => {
                set_err_msg_and_throw_exception(&mut env, obj, ERROR_CODE_ETC, e.to_string());
                return -1;
            }
        },
        Err(e) => {
            set_err_msg_and_throw_exception(&mut env, obj, ERROR_CODE_ETC, e.to_string());
            return -1;
        }
    };

    let db = match Database::open_file(io.clone(), &path) {
        Ok(db) => db,
        Err(e) => {
            set_err_msg_and_throw_exception(&mut env, obj, ERROR_CODE_ETC, e.to_string());
            return -1;
        }
    };

    Box::into_raw(Box::new(db)) as jlong
}

#[no_mangle]
pub extern "system" fn Java_org_github_tursodatabase_core_LimboDB_connect0<'local>(
    mut env: JNIEnv<'local>,
    obj: JObject<'local>,
    db_pointer: jlong,
) -> jlong {
    let db = match to_db(db_pointer) {
        Ok(db) => db,
        Err(e) => {
            set_err_msg_and_throw_exception(&mut env, obj, ERROR_CODE_ETC, e.to_string());
            return 0;
        }
    };

    Box::into_raw(Box::new(db.connect())) as jlong
}

fn to_db(db_pointer: jlong) -> Result<&'static mut Arc<Database>> {
    if db_pointer == 0 {
        Err(LimboError::InvalidDatabasePointer)
    } else {
        unsafe { Ok(&mut *(db_pointer as *mut Arc<Database>)) }
    }
}

#[no_mangle]
pub extern "system" fn Java_org_github_tursodatabase_core_LimboDB_throwJavaException<'local>(
    mut env: JNIEnv<'local>,
    obj: JObject<'local>,
    error_code: jint,
) {
    set_err_msg_and_throw_exception(
        &mut env,
        obj,
        error_code,
        "throw java exception".to_string(),
    );
}

fn utf8_byte_arr_to_str(env: &JNIEnv, bytes: JByteArray) -> Result<String> {
    let bytes = env
        .convert_byte_array(bytes)
        .map_err(|e| LimboError::CustomError("Failed to retrieve bytes".to_string()))?;
    let str = String::from_utf8(bytes).map_err(|e| {
        LimboError::CustomError("Failed to convert utf8 byte array into string".to_string())
    })?;
    Ok(str)
}

/// Sets the error message and throws a Java exception.
///
/// This function converts the provided error message to a byte array and calls the
/// `throwLimboException` method on the provided Java object to throw an exception.
///
/// # Parameters
/// - `env`: The JNI environment.
/// - `obj`: The Java object on which the exception will be thrown.
/// - `err_code`: The error code corresponding to the exception. Refer to `org.github.tursodatabase.core.Codes` for the list of error codes.
/// - `err_msg`: The error message to be included in the exception.
///
/// # Example
/// ```rust
/// set_err_msg_and_throw_exception(env, obj, Codes::SQLITE_ERROR, "An error occurred".to_string());
/// ```
fn set_err_msg_and_throw_exception<'local>(
    env: &mut JNIEnv<'local>,
    obj: JObject<'local>,
    err_code: i32,
    err_msg: String,
) {
    let error_message_bytes = env
        .byte_array_from_slice(err_msg.as_bytes())
        .expect("Failed to convert to byte array");
    match env.call_method(
        obj,
        "throwLimboException",
        "(I[B)V",
        &[err_code.into(), (&error_message_bytes).into()],
    ) {
        Ok(_) => {
            // do nothing because above method will always return Err
        }
        Err(_e) => {
            // do nothing because our java app will handle Err
        }
    }
}