assemble-core 0.2.0

use std::any::type_name;
use std::collections::HashSet;
use std::fmt::{Debug, Formatter};
use std::marker::PhantomData;
use std::sync::{Arc, Mutex};

use crate::defaults::tasks::Empty;
use crate::error::PayloadError;
use crate::exception::BuildException;
use crate::identifier::{InvalidId, TaskId};
use crate::immutable::Immutable;
use crate::lazy_evaluation::{Provider, ProviderError};
use crate::project::buildable::{Buildable, IntoBuildable};
use crate::project::error::{ProjectError, ProjectResult};
use crate::project::shared::SharedProject;
use crate::project::shared::WeakSharedProject;
use crate::task::flags::{OptionDeclarations, OptionsDecoder};
use crate::task::up_to_date::UpToDate;
use crate::task::{BuildableTask, FullTask, HasTaskId, TaskOrdering};
use crate::{BuildResult, Executable, Project};

use super::ExecutableTask;
use super::Task;

pub struct ConfigureTask<T: Task> {
    func: Box<dyn FnOnce(&mut Executable<T>, &Project) -> ProjectResult + Send>,
}

impl<T: Task> Debug for ConfigureTask<T> {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        write!(f, "<configure task type <{}>>", type_name::<T>())
    }
}

impl<T: Task> ConfigureTask<T> {
    pub fn configure(self, task: &mut Executable<T>, project: &Project) -> ProjectResult {
        (self.func)(task, project)
    }
}

pub trait ResolveTask {
    type Executable: ExecutableTask;

    fn resolve_task(self, project: &SharedProject) -> ProjectResult<Self::Executable>;
}

pub trait ResolveInnerTask: Send {
    fn resolve_task(&mut self, project: &SharedProject) -> ProjectResult<()>;
}

assert_obj_safe!(ResolveInnerTask);

#[derive(Debug)]
pub struct LazyTask<T: Task + Send + Debug + 'static> {
    task_type: PhantomData<T>,
    task_id: Immutable<TaskId>,
    configurations: Vec<ConfigureTask<T>>,
    shared: Option<WeakSharedProject>,
}

impl<T: Task + Send + Debug + 'static> LazyTask<T> {
    fn new(id: TaskId, shared: &WeakSharedProject) -> Self {
        Self {
            task_type: PhantomData,
            task_id: Immutable::new(id),
            configurations: vec![],
            shared: Some(shared.clone()),
        }
    }

    fn empty() -> Self {
        Self {
            task_type: PhantomData,
            task_id: Immutable::default(),
            configurations: vec![],
            shared: None,
        }
    }
}

impl<T: Task + Send + Sync + Debug + 'static> ResolveTask for LazyTask<T> {
    type Executable = Executable<T>;

    fn resolve_task(self, project: &SharedProject) -> ProjectResult<Executable<T>> {
        trace!("Resolving task {}", self.task_id.as_ref());
        let task = project.with(|project| T::new(self.task_id.as_ref(), project))?;
        let mut executable = Executable::new(
            self.shared
                .unwrap()
                .upgrade()
                .expect("could not upgrade project"),
            task,
            self.task_id,
        );

        project.with(|project| executable.initialize(project))?;
        executable.configure_io()?;

        for config in self.configurations {
            project.with(|project| config.configure(&mut executable, project))?;
        }

        Ok(executable)
    }
}

#[derive(Debug)]
enum TaskHandleInner<T: Task + Send + Sync + Debug + 'static> {
    Lazy(LazyTask<T>),
    Configured(Executable<T>),
}

impl<T: Task + Send + Sync + Debug + 'static> TaskHandleInner<T> {
    fn bare_resolve(&mut self) -> ProjectResult<()> {
        let project = match self {
            TaskHandleInner::Lazy(l) => l
                .shared
                .as_ref()
                .ok_or(ProjectError::NoSharedProjectSet)?
                .clone(),
            TaskHandleInner::Configured(_) => {
                return Ok(());
            }
        };
        let project = project.upgrade()?;
        self.resolve(&project)
    }

    fn resolve(&mut self, project: &SharedProject) -> ProjectResult<()> {
        let configured: Executable<T> = match self {
            TaskHandleInner::Lazy(lazy) => {
                let lazy = std::mem::replace(lazy, LazyTask::empty());
                lazy.resolve_task(project)?
            }
            TaskHandleInner::Configured { .. } => return Ok(()),
        };
        *self = TaskHandleInner::Configured(configured);
        Ok(())
    }

    fn bare_configured(&mut self) -> ProjectResult<&Executable<T>> {
        self.bare_resolve()?;
        if let TaskHandleInner::Configured(exec) = &*self {
            Ok(exec)
        } else {
            panic!("task should be configured")
        }
    }

    fn bare_configured_mut(&mut self) -> ProjectResult<&mut Executable<T>> {
        self.bare_resolve()?;
        if let TaskHandleInner::Configured(exec) = &mut *self {
            Ok(exec)
        } else {
            panic!("task should be configured")
        }
    }

    fn configured(&mut self, project: &SharedProject) -> ProjectResult<&Executable<T>> {
        self.resolve(project)?;
        if let TaskHandleInner::Configured(exec) = &*self {
            Ok(exec)
        } else {
            panic!("task should be configured")
        }
    }

    fn configured_mut(&mut self, project: &SharedProject) -> ProjectResult<&mut Executable<T>> {
        self.resolve(project)?;
        if let TaskHandleInner::Configured(exec) = &mut *self {
            Ok(exec)
        } else {
            panic!("task should be configured")
        }
    }
}

impl<T: Task + Send + Sync + Debug + 'static> ResolveInnerTask for TaskHandleInner<T> {
    fn resolve_task(&mut self, project: &SharedProject) -> ProjectResult<()> {
        self.resolve(project)
    }
}

pub struct TaskHandle<T: Task + Send + Sync + Debug + 'static> {
    id: TaskId,
    connection: Arc<Mutex<TaskHandleInner<T>>>,
}

impl<T: Task + Send + Sync + Debug + 'static> UpToDate for TaskHandle<T> {
    fn up_to_date(&self) -> bool {
        let mut guard = {
            if let Ok(guard) = self.connection.lock() {
                guard
            } else {
                return false;
            }
        };
        if let Ok(configured) = guard.bare_configured() {
            configured.task_up_to_date()
        } else {
            false
        }
    }
}

impl<T: Task + Send + Sync + Debug + 'static> TaskHandle<T> {
    /// Gets the id of the created task.
    pub fn id(&self) -> &TaskId {
        &self.id
    }

    pub fn configure_with<F>(&mut self, config: F) -> ProjectResult
    where
        F: FnOnce(&mut Executable<T>, &Project) -> ProjectResult + Send + 'static,
    {
        let mut guard = self.connection.lock().map_err(PayloadError::new)?;
        match &mut *guard {
            TaskHandleInner::Lazy(lazy) => {
                lazy.configurations.push(ConfigureTask {
                    func: Box::new(config),
                });
            }
            TaskHandleInner::Configured(c) => {
                let shared_project = c.project();
                shared_project.with(|project| (config)(c, project))?;
            }
        }
        Ok(())
    }

    fn configured<R, F: FnOnce(&Executable<T>) -> R>(&self, func: F) -> ProjectResult<R> {
        Ok((func)(
            self.connection
                .lock()
                .map_err(PayloadError::new)?
                .bare_configured()?,
        ))
    }

    pub fn provides<F, R>(&self, func: F) -> TaskProvider<T, R, F>
    where
        F: Fn(&Executable<T>) -> R + Send + Sync,
        R: Clone + Send + Sync,
    {
        TaskProvider::new(self.clone(), func)
    }
}

assert_impl_all!(TaskHandle<Empty>: Sync);

impl<T: Task + Send + Sync + Debug + 'static> Debug for TaskHandle<T> {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        if f.alternate() {
            f.debug_struct("TaskHandle")
                .field("type", &type_name::<T>())
                .field("id", &self.id)
                .finish()
        } else {
            write!(f, "{:?}", self.id)
        }
    }
}

impl<T: Task + Send + Sync + Debug + 'static> Buildable for TaskHandle<T> {
    fn get_dependencies(&self, project: &Project) -> ProjectResult<HashSet<TaskId>> {
        let mut guard = self.connection.lock().map_err(PayloadError::new)?;
        let configured = guard.configured(&project.as_shared())?;
        configured.into_buildable().get_dependencies(project)
    }
}

impl<T: Task + Send + Sync + Debug + 'static> HasTaskId for TaskHandle<T> {
    fn task_id(&self) -> TaskId {
        self.id.clone()
    }
}

impl<T: Task + Send + Sync + Debug + 'static> BuildableTask for TaskHandle<T> {
    fn ordering(&self) -> Vec<TaskOrdering> {
        let mut guard = self.connection.lock().unwrap();
        guard
            .bare_configured()
            .expect("could not get configured")
            .ordering()
    }
}

impl<T: Task + Send + Sync + Debug + 'static> Clone for TaskHandle<T> {
    fn clone(&self) -> Self {
        Self {
            id: self.id.clone(),
            connection: self.connection.clone(),
        }
    }
}

impl<T: Task + Send + Sync + Debug + 'static> ResolveInnerTask for TaskHandle<T> {
    fn resolve_task(&mut self, project: &SharedProject) -> ProjectResult<()> {
        self.connection
            .lock()
            .map_err(PayloadError::new)?
            .resolve_task(project)
    }
}
impl<T: Task + Send + Sync + Debug + 'static> ExecutableTask for TaskHandle<T> {
    fn options_declarations(&self) -> Option<OptionDeclarations> {
        let mut guard = self.connection.lock().unwrap();
        guard.bare_configured().unwrap().options_declarations()
    }

    fn try_set_from_decoder(&mut self, decoder: &OptionsDecoder) -> ProjectResult<()> {
        let mut guard = self
            .connection
            .lock()
            .map_err(|_| ProjectError::PoisonError)?;
        guard
            .bare_configured_mut()
            .unwrap()
            .try_set_from_decoder(decoder)
    }

    fn execute(&mut self, project: &Project) -> BuildResult {
        let mut guard = self
            .connection
            .lock()
            .map_err(|_| BuildException::new("Could not get access to provider"))?;
        guard.configured_mut(&project.as_shared())?.execute(project)
    }

    fn did_work(&self) -> bool {
        let mut guard = self
            .connection
            .lock()
            .map_err(|_| BuildException::new("Could not get access to provider"))
            .unwrap();
        guard.bare_configured().unwrap().did_work()
    }

    fn task_up_to_date(&self) -> bool {
        let mut guard = self
            .connection
            .lock()
            .map_err(|_| BuildException::new("Could not get access to provider"))
            .unwrap();
        guard.bare_configured().unwrap().task_up_to_date()
    }

    fn group(&self) -> String {
        self.configured(|e| e.group()).unwrap()
    }

    fn description(&self) -> String {
        self.configured(|e| e.description()).unwrap()
    }
}

pub trait ResolveExecutable: ResolveInnerTask {
    fn get_executable(&mut self, project: &SharedProject) -> ProjectResult<Box<dyn FullTask>>;
}

impl<T: Task + Send + Sync + Debug + 'static> ResolveExecutable for TaskHandle<T> {
    fn get_executable(&mut self, project: &SharedProject) -> ProjectResult<Box<dyn FullTask>> {
        self.resolve_task(project)?;
        Ok(Box::new(self.clone()))
    }
}

pub struct TaskProvider<T, R, F>
where
    T: Task + Send + Sync + Debug + 'static,
    F: Fn(&Executable<T>) -> R + Send + Sync,
    R: Clone + Send + Sync,
{
    handle: TaskHandle<T>,
    lift: F,
}

impl<T, R, F> Clone for TaskProvider<T, R, F>
where
    T: Task + Send + Sync + Debug + 'static,
    F: Fn(&Executable<T>) -> R + Send + Sync + Clone,
    R: Clone + Send + Sync,
{
    fn clone(&self) -> Self {
        Self {
            handle: self.handle.clone(),
            lift: self.lift.clone(),
        }
    }
}

impl<T, F, R> Buildable for TaskProvider<T, R, F>
where
    F: Fn(&Executable<T>) -> R + Send + Sync,
    R: Clone + Send + Sync,
    T: 'static + Debug + Send + Task + Sync,
{
    fn get_dependencies(&self, _: &Project) -> ProjectResult<HashSet<TaskId>> {
        Ok(HashSet::from_iter([self.handle.id.clone()]))
    }
}

impl<T, F, R> Debug for TaskProvider<T, R, F>
where
    F: Fn(&Executable<T>) -> R + Send + Sync,
    R: Clone + Send + Sync,
    T: 'static + Debug + Send + Task + Sync,
{
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("TaskProvider")
            .field("handle", &self.handle)
            .finish_non_exhaustive()
    }
}

impl<T, F, R> Provider<R> for TaskProvider<T, R, F>
where
    T: Task + Send + Sync + Debug + 'static,
    F: Fn(&Executable<T>) -> R + Send + Sync,
    R: Clone + Send + Sync,
{
    fn missing_message(&self) -> String {
        format!("couldn't get a value from task {}", self.handle.id)
    }

    fn try_get(&self) -> Option<R> {
        let mut guard = self.handle.connection.lock().expect("Could not get inner");
        let configured = guard.bare_configured().expect("could not configure task");
        Some((self.lift)(configured))
    }

    fn fallible_get(&self) -> Result<R, ProviderError> {
        let mut guard = self
            .handle
            .connection
            .lock()
            .map_err(|e| ProviderError::new(e.to_string()))?;
        let configured = guard
            .bare_configured()
            .map_err(|e| ProviderError::new(e.to_string()))?;
        Ok((self.lift)(configured))
    }
}

impl<T, F, R> TaskProvider<T, R, F>
where
    T: Task + Send + Sync + Debug + 'static,
    F: Fn(&Executable<T>) -> R + Send + Sync,
    R: Clone + Send + Sync,
{
    pub fn new(handle: TaskHandle<T>, lift: F) -> Self {
        Self { handle, lift }
    }
}

#[derive(Debug)]
pub struct TaskHandleFactory {
    project: WeakSharedProject,
}

impl TaskHandleFactory {
    pub(crate) fn new(project: WeakSharedProject) -> Self {
        Self { project }
    }

    /// Creates a task handle that's not configured
    pub fn create_handle<T: Task + Send + Sync + Debug + 'static>(
        &self,
        id: TaskId,
    ) -> Result<TaskHandle<T>, InvalidId> {
        let lazy = LazyTask::<T>::new(id.clone(), &self.project);
        let inner = TaskHandleInner::Lazy(lazy);
        Ok(TaskHandle {
            id,
            connection: Arc::new(Mutex::new(inner)),
        })
    }
}

#[cfg(test)]
mod tests {

    #[test]
    fn lazy_create_task() {}
}