use crate::FileId;
use crate::ast;
use crate::rules::manual_inherit::ManualInherit;
use crate::rules::manual_inherit_from::ManualInheritFrom;
use crate::rules::unquoted_uri::UnquotedUri;
use crate::scope_graph::ScopeGraph;

pub mod let_order;
pub mod manual_inherit;
pub mod manual_inherit_from;
pub mod unquoted_uri;

#[derive(Debug)]
pub struct Diagnostic {
    pub file_id: FileId,
    pub finding: Finding,
}

#[derive(Debug)]
pub struct Finding {
    pub rule_id: &'static str,
    pub range: ast::SourceRange,
    pub message: &'static str,
    pub binding: Option<String>,
}

impl std::fmt::Display for Diagnostic {
    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            formatter,
            "[{}] {}",
            self.finding.rule_id, self.finding.message
        )?;

        if let Some(binding) = &self.finding.binding {
            write!(formatter, ": {binding}")?;
        }

        Ok(())
    }
}

pub trait NodeRule {
    type Node;

    const ID: &'static str;

    fn select(data: &ast::NodeData) -> Option<&Self::Node>;
    fn check(node: &Self::Node) -> Option<&'static str>;
}

pub trait TokenRule {
    type Token;

    const ID: &'static str;

    fn select(data: &ast::TokenData) -> Option<&Self::Token>;
    fn check(token: &Self::Token) -> Option<&'static str>;
}

pub fn run_rules(file: &ast::ParsedFile, graph: &ScopeGraph) -> Vec<Diagnostic> {
    let node_diagnostics = file
        .nodes
        .iter()
        .flat_map(|node| {
            [
                run_node_rule::<ManualInherit>(node),
                run_node_rule::<ManualInheritFrom>(node),
            ]
        })
        .flatten();
    let token_diagnostics = file
        .tokens
        .iter()
        .flat_map(|token| [run_token_rule::<UnquotedUri>(token)])
        .flatten();

    let let_order_diagnostics = let_order::check(graph).into_iter().map(|finding| Finding {
        rule_id: "let_order",
        range: finding.range,
        message: "Let bindings must follow dependency order",
        binding: Some(finding.binding),
    });

    node_diagnostics
        .chain(token_diagnostics)
        .chain(let_order_diagnostics)
        .map(|finding| Diagnostic {
            file_id: file.file_id,
            finding,
        })
        .collect()
}

fn run_node_rule<R>(node: &ast::Node) -> Option<Finding>
where
    R: NodeRule,
{
    let typed_node = R::select(&node.data)?;
    let message = R::check(typed_node)?;

    Some(Finding {
        rule_id: R::ID,
        range: node.range,
        message,
        binding: None,
    })
}

fn run_token_rule<R>(token: &ast::Token) -> Option<Finding>
where
    R: TokenRule,
{
    let typed_token = R::select(&token.data)?;
    let message = R::check(typed_token)?;

    Some(Finding {
        rule_id: R::ID,
        range: token.range,
        message,
        binding: None,
    })
}