1 files changed, 456 insertions, 0 deletions
diff --git a/converge/src/main.rs b/converge/src/main.rs
new file mode 100644
index 0000000..20f2683
--- /dev/null
+++ b/converge/src/main.rs
@@ -0,0 +1,456 @@
+use std::str::FromStr;
+
+use camino::Utf8PathBuf;
+
+fn main() {
+	let mut args = std::env::args().skip(1);
+	let argc = args.len();
+	if argc == 0 {
+		eprintln!("usage: converge <content file> [supporting files ...]");
+		return;
+	}
+
+	let content = match args.next() {
+		None => {
+			eprintln!("usage: converge <content file> [supporting files ...]");
+			return;
+		}
+		Some(path) => Utf8PathBuf::from(path),
+	};
+
+	let supporting = args.map(Utf8PathBuf::from).collect();
+
+	let html = process(content, supporting);
+	println!("{html}")
+}
+
+fn process(content_file: Utf8PathBuf, mut supporting: Vec<Utf8PathBuf>) -> cutie::Html {
+	println!("{content_file}");
+	let raw = std::fs::read_to_string(&content_file).unwrap();
+
+	match Part::from_str(&raw) {
+		Err(PartError::NoSetup) => cutie::Html::parse(raw),
+		Err(e) => {
+			eprintln!("{e}");
+			std::process::exit(1);
+		}
+		Ok(part) => {
+			let setup = part.setup;
+			let setup_path = match supporting
+				.iter()
+				.position(|p| p.file_name().unwrap() == setup)
+			{
+				None => {
+					eprintln!("failed to find setup file {setup}");
+					std::process::exit(1);
+				}
+				Some(idx) => supporting.swap_remove(idx),
+			};
+
+			let mut html = process(setup_path, supporting);
+
+			for Action { command, content } in part.actions {
+				let mut content_html = cutie::Html::parse(content);
+
+				let ident = if let Identifier::Tag(tag) = command.identifier {
+					tag
+				} else {
+					panic!()
+				};
+
+				fn get_tag<'a>(html: &'a mut cutie::Html, ident: &str) -> &'a mut cutie::Tag {
+					match html.get_by_tag_name_mut(&ident) {
+						None => {
+							eprintln!("error processing file");
+							eprintln!("failed to find element with tag {ident}");
+							std::process::exit(1);
+						}
+						Some(tag) => tag,
+					}
+				}
+
+				fn get_parent_tag<'a>(
+					html: &'a mut cutie::Html,
+					ident: &str,
+				) -> &'a mut cutie::Tag {
+					match html.get_parent_that_contains_tag_name_mut(&ident) {
+						None => {
+							eprintln!("error processing file");
+							eprintln!("failed to find element with tag {ident}");
+							std::process::exit(1);
+						}
+						Some(tag) => tag,
+					}
+				}
+
+				match command.opcode {
+					Opcode::ReplaceChildren => {
+						let tag = get_tag(&mut html, &ident);
+						tag.children = content_html.nodes;
+					}
+					Opcode::Push => {
+						let tag = get_tag(&mut html, &ident);
+						tag.children.extend(content_html.nodes);
+					}
+					Opcode::Before => {
+						println!("BEFORE");
+						let predicate = |node: &cutie::Node| -> bool {
+							if let cutie::Node::Tag(tag) = node {
+								if tag.name == ident {
+									return true;
+								}
+							}
+
+							false
+						};
+
+						let parent = get_parent_tag(&mut html, &ident);
+						match parent.children.iter().position(predicate) {
+							None => panic!(),
+							Some(idx) => {
+								for node in content_html.nodes.into_iter().rev() {
+									parent.children.insert(idx, node);
+								}
+							}
+						}
+					}
+					Opcode::Replace => {
+						let parent = get_parent_tag(&mut html, &ident);
+						match parent.by_tag_mut(&ident) {
+							None => {
+								eprintln!("error processing file");
+								eprintln!("failed to find element with tag {ident}");
+								std::process::exit(1);
+							}
+							Some(tag) => match content_html.nodes.swap_remove(0) {
+								cutie::Node::Tag(content_tag) => *tag = content_tag,
+								_ => {
+									eprintln!(
+										"OpCode was Replace but no HTML tag as first content"
+									);
+									std::process::exit(1);
+								}
+							},
+						}
+					}
+				}
+			}
+
+			html
+		}
+	}
+}
+
+pub struct Part {
+	setup: Utf8PathBuf,
+	actions: Vec<Action>,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct Action {
+	command: Command,
+	content: String,
+}
+
+#[rustfmt::skip] // it was bothering me
+impl FromStr for Part {
+	type Err = PartError;
+
+	fn from_str(mut raw: &str) -> Result<Self, Self::Err> {
+		let setup = if let Some(stripped) = raw.strip_prefix("Setup: ") {
+			match stripped.find('\n') {
+				None => return Err(PartError::NoSetup),
+				Some(nl_idx) => {
+					let path = &stripped[..nl_idx];
+					raw = &stripped[nl_idx + 1..];
+					Utf8PathBuf::from(path)
+				}
+			}
+		} else { return Err(PartError::NoSetup) };
+
+		let mut actions = vec![];
+		loop {
+			// Skip newlines between blocks
+			while let Some("\n") = raw.get(0..1) { raw = &raw[1..]; }
+
+			let command = match extract_command_from_start(raw)? {
+				None => {
+					if raw.trim().is_empty() {
+						// permissive about the file ending in any whitespace
+						break;
+					} else {
+						let line = raw.split('\n').next().unwrap_or(raw).to_owned();
+						return Err(PartError::IncorrectCommand { line });
+					}
+				},
+				Some(ExtractedCommand { command, after }) => {
+					raw = after;
+					command
+				}
+			};
+
+			// Check for 1-line actions
+			let (sla_line, sla_after) = match raw.find('\n') {
+				None => {
+					let line = raw.trim();
+					if line.is_empty() {
+						return Err(PartError::EmptyAction);
+					} else {
+						(line, &raw[raw.len()..])
+					}
+				},
+				Some(nl_idx) => {
+					(raw[..nl_idx].trim(), &raw[nl_idx+1..])
+				}
+			};
+
+			// We're a one-line action!
+			if !sla_line.is_empty() {
+				actions.push(Action { command, content: sla_line.to_owned() });
+				raw = sla_after;
+				continue;
+			} else {
+				// not single-line, trim the front
+				raw = raw.trim_start();
+			}
+
+			// If we're here, it's a multiline action
+			let mut consumed = 0;
+			loop {
+				let wrk = &raw[consumed..];
+
+				match wrk.find("\n\n") {
+					None => {
+						consumed = raw.len();
+						break;
+					},
+					Some(dnl_idx) => {
+						consumed += dnl_idx;
+
+						if extract_command_from_start(&wrk[dnl_idx+2..])?.is_some() {
+							break;
+						} else {
+							consumed += 2;
+						}
+					}
+				}
+			}
+		
+			let content = &raw[..consumed];
+
+			if content.trim().is_empty() {
+				return Err(PartError::EmptyAction);
+			}
+
+			actions.push(Action { command, content: content.to_owned() });
+			raw = &raw[consumed..];
+		}
+
+		Ok(Self {
+			setup,
+			actions
+		})
+	}
+}
+
+fn extract_command_from_start(raw: &str) -> Result<Option<ExtractedCommand>, PartError> {
+	// we don't change the start here. indexing back into raw with an index from
+	// line is safe.
+	let line = match raw.find('\n') {
+		None => raw,
+		Some(nl_idx) => &raw[..nl_idx],
+	};
+
+	Ok(match line.find('}') {
+		None => None,
+		Some(end_idx) => {
+			if line.starts_with('{') {
+				Some(ExtractedCommand {
+					command: raw[1..end_idx].parse()?,
+					after: &raw[end_idx + 1..],
+				})
+			} else {
+				None
+			}
+		}
+	})
+}
+
+#[derive(Clone, Debug, PartialEq)]
+struct Command {
+	identifier: Identifier,
+	opcode: Opcode,
+}
+
+impl FromStr for Command {
+	type Err = PartError;
+
+	fn from_str(s: &str) -> Result<Self, Self::Err> {
+		let (raw_opcode, raw_identifier) = match s.split_once('-') {
+			None => ("", s.trim()),
+			Some((op, ident)) => (op.trim(), ident.trim()),
+		};
+
+		let opcode = match raw_opcode {
+			"" | "replace children" => Opcode::ReplaceChildren,
+			"replace" => Opcode::Replace,
+			"before" => Opcode::Before,
+			"push" => Opcode::Push,
+			_ => {
+				return Err(PartError::InvalidOperation {
+					op: raw_opcode.to_owned(),
+				})
+			}
+		};
+
+		Ok(Command {
+			//TODO: allow operating with IDs
+			identifier: Identifier::Tag(raw_identifier.to_owned()),
+			opcode,
+		})
+	}
+}
+
+#[derive(Clone, Debug, PartialEq)]
+enum Identifier {
+	Tag(String),
+}
+
+#[derive(Clone, Debug, PartialEq)]
+enum Opcode {
+	ReplaceChildren,
+	Replace,
+	Before,
+	Push,
+}
+
+struct ExtractedCommand<'r> {
+	command: Command,
+	after: &'r str,
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum PartError {
+	#[error("part needs to start with a setup! like this:\n\"Setup: <path>\"")]
+	NoSetup,
+	#[error("command has no content")]
+	EmptyAction,
+	#[error("the command-line is incorrect: {line}")]
+	IncorrectCommand { line: String },
+	#[error("the operation {op} is invalid")]
+	InvalidOperation { op: String },
+}
+
+#[cfg(test)]
+mod test {
+	use crate::{extract_command_from_start, Action, Command, Identifier, Opcode, Part};
+
+	macro_rules! str {
+		($str:literal) => {
+			String::from($str)
+		};
+	}
+
+	macro_rules! cmd {
+		($id:expr) => {
+			Command {
+				identifier: Identifier::Tag(String::from($id)),
+				opcode: Opcode::ReplaceChildren,
+			}
+		};
+	}
+
+	#[test]
+	fn extracts_command() {
+		let raw = "{cmd} single line";
+		let ext = extract_command_from_start(raw).unwrap().unwrap();
+
+		assert_eq!(ext.command, cmd!("cmd"));
+		assert_eq!(ext.after, " single line");
+	}
+
+	#[test]
+	fn extracts_command_newline() {
+		let raw = "{cmd}\nnext line";
+		let ext = extract_command_from_start(raw).unwrap().unwrap();
+
+		assert_eq!(ext.command, cmd!("cmd"));
+		assert_eq!(ext.after, "\nnext line");
+	}
+
+	#[test]
+	fn extracts_simple_part() {
+		let raw = "Setup: setup.html\n\n{cmd} content";
+		let part: Part = raw.parse().unwrap();
+
+		assert_eq!(part.setup, "setup.html");
+		assert_eq!(
+			part.actions,
+			vec![Action {
+				command: cmd!("cmd"),
+				content: str!("content")
+			}]
+		)
+	}
+
+	#[test]
+	fn extracts_simple_part_multiline() {
+		let raw = "Setup: setup.html\n\n{cmd}\ncontent";
+		let part: Part = raw.parse().unwrap();
+
+		assert_eq!(part.setup, "setup.html");
+		assert_eq!(
+			part.actions,
+			vec![Action {
+				command: cmd!("cmd"),
+				content: str!("content")
+			}]
+		)
+	}
+
+	#[test]
+	fn extracts_simple_part_multiple_singleline() {
+		let raw = "Setup: setup.html\n\n{cmd} content\n{cmd2} contents2";
+		let part: Part = raw.parse().unwrap();
+
+		assert_eq!(part.setup, "setup.html");
+		assert_eq!(
+			part.actions,
+			vec![
+				Action {
+					command: cmd!("cmd"),
+					content: str!("content")
+				},
+				Action {
+					command: cmd!("cmd2"),
+					content: str!("content2")
+				}
+			]
+		)
+	}
+
+	#[test]
+	fn extracts_simple_part_multiple_actions() {
+		let raw = "Setup: setup.html\n\n{cmd} content\n{cmd2}\ncontent2\n{bait}\n\n{cmd3}\ncontent";
+		let part: Part = raw.parse().unwrap();
+
+		assert_eq!(part.setup, "setup.html");
+		assert_eq!(
+			part.actions,
+			vec![
+				Action {
+					command: cmd!("cmd"),
+					content: str!("content")
+				},
+				Action {
+					command: cmd!("cmd2"),
+					content: str!("content2\n{bait}")
+				},
+				Action {
+					command: cmd!("cmd3"),
+					content: str!("content")
+				}
+			]
+		)
+	}
+}