surrealdb-core-nightly 2.1.20250111

use crate::ctx::Context;
use crate::dbs::Options;
use crate::err::Error;
use crate::sql::edges::Edges;
use crate::sql::field::{Field, Fields};
use crate::sql::part::Next;
use crate::sql::part::Part;
use crate::sql::statements::select::SelectStatement;
use crate::sql::value::{Value, Values};
use futures::future::try_join_all;
use reblessive::tree::Stk;

impl Value {
	pub(crate) async fn fetch(
		&mut self,
		stk: &mut Stk,
		ctx: &Context,
		opt: &Options,
		path: &[Part],
	) -> Result<(), Error> {
		let mut this = self;
		let mut iter = path.iter();
		let mut prev = path;

		// Loop over the path.
		// If the we just need to select a sub section of a value we update this to point to the
		// new subsection of the value. Otherwise we call into fetch again and then immediately
		// return.
		// If we encounter a idiom application which does not make sense, like `(1).foo` just
		// return Ok(())
		while let Some(p) = iter.next() {
			match p {
				Part::Graph(g) => match this {
					Value::Object(o) => {
						let Some(v) = o.rid() else {
							return Ok(());
						};

						let mut v = Value::Thing(v);
						return stk.run(|stk| v.fetch(stk, ctx, opt, iter.as_slice())).await;
					}
					Value::Thing(x) => {
						let stm = SelectStatement {
							expr: Fields(vec![Field::All], false),
							what: Values(vec![Value::from(Edges {
								from: x.clone(),
								dir: g.dir.clone(),
								what: g.what.clone(),
							})]),
							cond: g.cond.clone(),
							..SelectStatement::default()
						};
						*this = stm
							.compute(stk, ctx, opt, None)
							.await?
							.all()
							.get(stk, ctx, opt, None, path.next())
							.await?
							.flatten()
							.ok()?;
						return Ok(());
					}
					Value::Array(x) => {
						// apply this path to every entry of the array.
						stk.scope(|scope| {
							let futs =
								x.iter_mut().map(|v| scope.run(|stk| v.fetch(stk, ctx, opt, prev)));
							try_join_all(futs)
						})
						.await?;
						return Ok(());
					}
					// break her to be comp
					_ => return Ok(()),
				},
				Part::Field(f) => match this {
					Value::Object(o) => {
						let Some(x) = o.get_mut(f.0.as_str()) else {
							return Ok(());
						};
						this = x;
					}
					Value::Array(x) => {
						// apply this path to every entry of the array.
						stk.scope(|scope| {
							let futs =
								x.iter_mut().map(|v| scope.run(|stk| v.fetch(stk, ctx, opt, prev)));
							try_join_all(futs)
						})
						.await?;
						return Ok(());
					}
					_ => break,
				},
				Part::Index(i) => match this {
					Value::Object(v) => {
						let Some(x) = v.get_mut(&i.to_string()) else {
							return Ok(());
						};
						this = x;
					}
					Value::Array(v) => {
						let Some(x) = v.get_mut(i.to_usize()) else {
							return Ok(());
						};
						this = x;
					}
					_ => break,
				},
				Part::Value(v) => {
					let v = v.compute(stk, ctx, opt, None).await?;
					match this {
						Value::Object(obj) => {
							let Some(x) = obj.get_mut(v.coerce_to_string()?.as_str()) else {
								return Ok(());
							};
							this = x;
						}
						Value::Array(array) => {
							if let Value::Range(x) = v {
								let Some(range) = x.slice(array) else {
									return Ok(());
								};
								let mut range = Value::Array(range.to_vec().into());
								return stk
									.run(|stk| range.fetch(stk, ctx, opt, iter.as_slice()))
									.await;
							}
							let Some(x) = array.get_mut(v.coerce_to_u64()? as usize) else {
								return Ok(());
							};
							this = x;
						}
						_ => return Ok(()),
					}
				}
				Part::Destructure(p) => match this {
					Value::Array(x) => {
						// apply this path to every entry of the array.
						stk.scope(|scope| {
							let futs =
								x.iter_mut().map(|v| scope.run(|stk| v.fetch(stk, ctx, opt, prev)));
							try_join_all(futs)
						})
						.await?;
					}
					Value::Object(_) => {
						for p in p.iter() {
							let mut destructure_path = p.path();
							destructure_path.extend_from_slice(path);
							stk.run(|stk| this.fetch(stk, ctx, opt, &destructure_path)).await?;
						}
						return Ok(());
					}
					_ => return Ok(()),
				},
				Part::All => match this {
					Value::Object(x) => {
						let next_path = iter.as_slice();
						// no need to spawn all those futures if their is no more paths to
						// calculate
						if next_path.is_empty() {
							break;
						}

						stk.scope(|scope| {
							let futs = x
								.iter_mut()
								.map(|(_, v)| scope.run(|stk| v.fetch(stk, ctx, opt, next_path)));
							try_join_all(futs)
						})
						.await?;
						return Ok(());
					}
					Value::Array(x) => {
						let next_path = iter.as_slice();
						// no need to spawn all those futures if their is no more paths to
						// calculate
						if next_path.is_empty() {
							break;
						}

						stk.scope(|scope| {
							let futs = x
								.iter_mut()
								.map(|v| scope.run(|stk| v.fetch(stk, ctx, opt, next_path)));
							try_join_all(futs)
						})
						.await?;
						return Ok(());
					}
					_ => break,
				},
				Part::First => match this {
					Value::Array(x) => {
						let Some(x) = x.first_mut() else {
							return Ok(());
						};
						this = x;
					}
					_ => return Ok(()),
				},
				Part::Last => match this {
					Value::Array(x) => {
						let Some(x) = x.last_mut() else {
							return Ok(());
						};
						this = x;
					}
					_ => return Ok(()),
				},
				Part::Where(w) => match this {
					Value::Array(x) => {
						for v in x.iter_mut() {
							let doc = v.clone().into();
							if w.compute(stk, ctx, opt, Some(&doc)).await?.is_truthy() {
								stk.run(|stk| v.fetch(stk, ctx, opt, iter.as_slice())).await?;
							}
						}
					}
					_ => return Ok(()),
				},
				_ => break,
			}
			prev = iter.as_slice();
		}

		// If the final value is on of following types we still need to compute it.
		match this {
			Value::Array(v) => {
				stk.scope(|scope| {
					let futs = v.iter_mut().map(|v| scope.run(|stk| v.fetch(stk, ctx, opt, path)));
					try_join_all(futs)
				})
				.await?;
				Ok(())
			}
			Value::Thing(v) => {
				// Clone the thing
				let val = v.clone();
				// Fetch the remote embedded record
				let stm = SelectStatement {
					expr: Fields(vec![Field::All], false),
					what: Values(vec![Value::from(val)]),
					..SelectStatement::default()
				};
				*this = stm.compute(stk, ctx, opt, None).await?.first();
				Ok(())
			}
			_ => Ok(()),
		}
	}
}