mod cstr_ffi;
mod last_error;
mod object_pool;

use object_pool::ObjectPool;
use std::sync::{LazyLock, RwLock};
use thiserror::Error as TeError;
use wfassoc::highlevel::{Program, Schema};

pub use cstr_ffi::CStyleString;
pub use object_pool::Token;

// region: Error

/// Error occurs in this crate.
#[derive(Debug, TeError)]
enum Error {
    /// Error when operating Schema.
    #[error("{0}")]
    Schema(#[from] wfassoc::highlevel::SchemaError),
    /// Error when parsing Schema into Program.
    #[error("{0}")]
    ParseProgram(#[from] wfassoc::highlevel::ParseProgramError),
    /// Error when operating Program.
    #[error("{0}")]
    Program(#[from] wfassoc::highlevel::ProgramError),

    /// Error when manipulating with C-style string.
    #[error("{0}")]
    CStrFfi(#[from] cstr_ffi::Error),
    /// Error when manipulating with object pool.
    #[error("{0}")]
    ObjectPool(#[from] object_pool::Error),

    /// Error when manipulating with poison RwLock
    #[error("RwLock is poisoning")]
    PoisonRwLock,
}

/// Result type used in this crate.
type Result<T> = std::result::Result<T, Error>;

// endregion

// region: Macros

macro_rules! in_param_ty {
    ($t:ty) => {
        $t
    };
}

macro_rules! out_param_ty {
    ($t:ty) => {
        *mut $t
    };
}

macro_rules! set_out_param {
    ($lhs:expr, $rhs:expr) => {
        unsafe { *$lhs = $rhs };
    };
}

macro_rules! pull_reader {
    ($pool:expr) => {
        $pool.read().map_err(|_| Error::PoisonRwLock)
    };
}

macro_rules! pull_writer {
    ($pool:expr) => {
        $pool.write().map_err(|_| Error::PoisonRwLock)
    };
}

// endregion

// region: Exposed Functions

// region: Facilities

#[unsafe(no_mangle)]
pub extern "C" fn WFStartup() -> bool {
    // TODO: Initialize all pool by fetching writer from them
    true
}

#[unsafe(no_mangle)]
pub extern "C" fn WFShutdown() -> bool {
    // TODO: Free all pool stored objects
    true
}

#[unsafe(no_mangle)]
pub extern "C" fn WFGetLastError() -> CStyleString {
    last_error::get_last_error()
}

#[unsafe(no_mangle)]
pub extern "C" fn WFHasPrivilege() -> bool {
    wfassoc::win32::utilities::has_privilege()
}

// endregion

// region: Schema

static SCHEMA_POOL: LazyLock<RwLock<ObjectPool<Schema>>> =
    LazyLock::new(|| RwLock::new(ObjectPool::new()));

#[unsafe(no_mangle)]
pub extern "C" fn WFSchemaCreate(out_schema: out_param_ty!(Token)) -> bool {
    fn inner() -> Result<Token> {
        let mut pool = pull_writer!(SCHEMA_POOL)?;
        Ok(pool.allocate(Schema::new())?)
    }

    match inner() {
        Ok(rv) => {
            set_out_param!(out_schema, rv);
            last_error::clear_last_error();
            true
        }
        Err(e) => {
            last_error::set_last_error(e.to_string().as_str());
            false
        }
    }
}

#[unsafe(no_mangle)]
pub extern "C" fn WFSchemaSetIdentifier(
    in_schema: in_param_ty!(Token),
    in_value: in_param_ty!(CStyleString),
) -> bool {
    fn inner(in_schema: Token, in_value: CStyleString) -> Result<()> {
        let mut pool = pull_writer!(SCHEMA_POOL)?;
        let schema = pool.get_mut(in_schema)?;
        schema.set_identifier(cstr_ffi::parse_ffi_string(in_value)?);
        Ok(())
    }

    match inner(in_schema, in_value) {
        Ok(_) => {
            last_error::clear_last_error();
            true
        }
        Err(e) => {
            last_error::set_last_error(e.to_string().as_str());
            false
        }
    }
}

#[unsafe(no_mangle)]
pub extern "C" fn WFSchemaIntoProgram(
    in_schema: in_param_ty!(Token),
    out_program: out_param_ty!(Token),
) -> bool {
    fn inner(in_token: Token) -> Result<Token> {
        let mut pool = pull_writer!(SCHEMA_POOL)?;
        let schema = pool.pop(in_token)?;

        let mut pool = pull_writer!(PROGRAM_POOL)?;
        let program = schema.into_program()?;
        Ok(pool.allocate(program)?)
    }

    match inner(in_schema) {
        Ok(rv) => {
            set_out_param!(out_program, rv);
            last_error::clear_last_error();
            true
        }
        Err(e) => {
            last_error::set_last_error(e.to_string().as_str());
            false
        }
    }
}

#[unsafe(no_mangle)]
pub extern "C" fn WFSchemaDestroy(in_schema: in_param_ty!(Token)) -> bool {
    fn inner(in_token: Token) -> Result<()> {
        let mut pool = pull_writer!(SCHEMA_POOL)?;
        Ok(pool.free(in_token)?)
    }

    match inner(in_schema) {
        Ok(_) => {
            last_error::clear_last_error();
            true
        }
        Err(e) => {
            last_error::set_last_error(e.to_string().as_str());
            false
        }
    }
}

// endregion

// region: Program

static PROGRAM_POOL: LazyLock<RwLock<ObjectPool<Program>>> =
    LazyLock::new(|| RwLock::new(ObjectPool::new()));

// endregion

// endregion