use serde::{Deserialize, Serialize};
use sha2::Sha256;
use std::{collections::HashMap, fmt::Display};

use crate::util::cjson;

#[derive(Clone, Copy, Debug)]
pub struct StringHash(pub [u8; 32]);

impl Display for StringHash {
	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
		f.write_str(&hex::encode(self.0))
	}
}

impl Serialize for StringHash {
	fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
	where
		S: serde::Serializer,
	{
		hex::serialize(self.0, serializer)
	}
}
impl<'de> Deserialize<'de> for StringHash {
	fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
	where
		D: serde::Deserializer<'de>,
	{
		Ok(StringHash(hex::deserialize(deserializer)?))
	}
}

pub type InputHasher = Sha256;
pub type InputHash = StringHash;

pub type OutputHasher = Sha256;
pub type OutputHash = StringHash;

pub type TaskID = String;

#[derive(Clone, Debug, Deserialize, Serialize)]
pub struct TaskDef {
	#[serde(default)]
	pub depends: Vec<TaskID>,
	#[serde(default)]
	pub run: String,
}

#[derive(Clone, Debug, Deserialize, Serialize)]
pub struct Task {
	pub id: TaskID,
	pub def: TaskDef,
	pub depends: HashMap<TaskID, OutputHash>,
	pub env: HashMap<String, String>,
}

impl Task {
	pub fn input_hash(&self) -> InputHash {
		StringHash(cjson::digest::<InputHasher, _>(self).unwrap().into())
	}
}

#[derive(Debug, Default)]
pub struct TaskMap(pub HashMap<String, TaskDef>);

impl TaskMap {
	pub fn get(&self, task: &TaskID) -> Option<&TaskDef> {
		self.0.get(task)
	}
}

#[derive(Clone, Debug, Deserialize, Serialize)]
pub struct TaskOutput {
	pub id: TaskID,
	pub depends: HashMap<TaskID, OutputHash>,
	pub env: HashMap<String, String>,
	pub input_hash: InputHash,
	pub output_hash: OutputHash,
}