use frontend::ast::visitor::{Visitor, walk_expr, walk_function};
use frontend::ast::{
    AST_SCHEMA_ID, AstDocument, AstError, AstRoot, Expr, ExprKind, Function, Spanned, StmtKind,
};
use frontend::{EndorReader, ParseMode, Span, parse_ast, parse_source_ast};

#[test]
fn function_bodies_accept_method_statements_and_optional_trailing_return() {
    let root = parse_ast(
        "function click(): Unit { title.setText(\"changed\") card.setColor(\"#FFEEDD\") }",
        ParseMode::Module,
    )
    .unwrap();
    let AstRoot::Module(program) = root else {
        panic!("expected module")
    };
    let function = program.functions().next().unwrap();
    assert_eq!(function.body.statements.len(), 2);
    assert!(
        function
            .body
            .statements
            .iter()
            .all(|s| matches!(s.kind, StmtKind::Expression(_)))
    );
    assert!(parse_ast("function empty(): Unit {}", ParseMode::Module).is_ok());
    assert!(
        parse_ast(
            "function invalid(): Unit { return value other() }",
            ParseMode::Module
        )
        .is_err()
    );
}

#[test]
fn parse_modes_produce_distinct_roots_and_preserve_source_diagnostics() {
    let source = "function echo(value: String): String { let copy = value return copy }";
    let root = parse_ast(source, ParseMode::Module).unwrap();
    let AstRoot::Module(program) = &root else {
        panic!("expected module")
    };
    let function = program.functions().next().unwrap();
    assert_eq!(function.body.statements.len(), 2);
    assert!(matches!(
        function.body.statements[0].kind,
        StmtKind::Binding(_)
    ));
    assert!(matches!(
        function.body.statements[1].kind,
        StmtKind::Return(_)
    ));
    AstDocument::new(root)
        .unwrap()
        .validate_source(source)
        .unwrap();

    let root = parse_ast("echo(\"日\")", ParseMode::Expression).unwrap();
    assert!(matches!(root, AstRoot::Expression(_)));
    for text in ["let value = \"日\"", "echo(value)", source] {
        let root = parse_ast(text, ParseMode::Interactive).unwrap();
        let AstRoot::Interactive(input) = &root else {
            panic!("expected interactive")
        };
        assert_eq!(input.statements.len(), 1);
        AstDocument::new(root)
            .unwrap()
            .validate_source(text)
            .unwrap();
    }
    assert!(parse_ast("let x = 1 let y = 2", ParseMode::Interactive).is_err());
    assert!(parse_ast("", ParseMode::Interactive).is_err());
    let source = EndorReader::from_text("<session:1>", "\"日\" + )");
    let error = parse_source_ast(&source, ParseMode::Expression).unwrap_err();
    assert_eq!(error.location.line, 1);
    assert_eq!(error.location.column, 7);
    assert!(error.to_string().starts_with("<session:1>:1:7:"));
}

#[test]
fn generated_visitors_reach_names_and_unwind_node_hooks_on_error() {
    #[derive(Default)]
    struct Names {
        functions: Vec<String>,
        references: Vec<String>,
        depth: usize,
        stop: bool,
    }
    impl Visitor for Names {
        type Error = &'static str;
        fn enter_node(&mut self, _span: Span) -> Result<(), Self::Error> {
            self.depth += 1;
            Ok(())
        }
        fn leave_node(&mut self) {
            self.depth -= 1;
        }
        fn visit_function(&mut self, node: &Function) -> Result<(), Self::Error> {
            self.functions.push(node.name.text.clone());
            walk_function(self, node)
        }
        fn visit_expr(&mut self, node: &Expr) -> Result<(), Self::Error> {
            if let ExprKind::Name(name) = &node.kind {
                if self.stop {
                    return Err("stopped at reference");
                }
                self.references.push(name.clone());
            }
            walk_expr(self, node)
        }
    }
    let root = parse_ast(
        "function echo(value: String): String { let copy = value return copy }",
        ParseMode::Module,
    )
    .unwrap();
    let mut names = Names::default();
    names.visit_ast_root(&root).unwrap();
    assert_eq!(names.functions, ["echo"]);
    assert_eq!(names.references, ["value", "copy"]);
    assert_eq!(names.depth, 0);
    let mut stopped = Names {
        stop: true,
        ..Names::default()
    };
    assert_eq!(stopped.visit_ast_root(&root), Err("stopped at reference"));
    assert_eq!(stopped.depth, 0);
}

#[test]
fn spans_share_unicode_locations_and_safe_original_source_access() {
    let source = " \r\n(値)";
    let root = parse_ast(source, ParseMode::Expression).unwrap();
    assert_eq!(root.source_text(source), Some("(値)"));
    let location = root.location(source).unwrap();
    assert_eq!((location.line, location.column), (2, 1));
    assert_eq!(Span::new(1, 3).slice("値"), None);
    assert_eq!(Span::new(2, 1).slice("値"), None);
    assert_eq!(Span::new(0, 4).location("値"), None);
}

#[test]
fn versioned_json_roundtrips_all_roots_and_preserves_number_spelling() {
    for (source, mode) in [
        (
            "function f(): Number { return 00012345678901234567890.00100 }",
            ParseMode::Module,
        ),
        ("f(.名前, \"日\\n\")", ParseMode::Expression),
        ("let value = 1", ParseMode::Interactive),
    ] {
        let document = AstDocument::new(parse_ast(source, mode).unwrap()).unwrap();
        let json = document.to_json().unwrap();
        let restored = AstDocument::from_json(&json).unwrap();
        assert_eq!(restored, document);
        restored.validate_source(source).unwrap();
        assert!(json.contains(AST_SCHEMA_ID));
        if mode == ParseMode::Module {
            assert!(json.contains("00012345678901234567890.00100"));
        }
    }
    let schema: serde_json::Value =
        serde_json::from_str(include_str!("../editor/ast.schema.json")).unwrap();
    assert_eq!(schema["$id"], AST_SCHEMA_ID);
    assert_eq!(
        schema["$defs"]["AstDocument"]["properties"]["schema"]["const"],
        AST_SCHEMA_ID
    );
    assert!(include_str!("../editor/ast.ts").contains(AST_SCHEMA_ID));
}

#[test]
fn json_interfaces_reject_unknown_fields_schema_changes_and_invalid_ranges() {
    let source = "(f(値))";
    let document = AstDocument::new(parse_ast(source, ParseMode::Expression).unwrap()).unwrap();
    let mut value = serde_json::to_value(&document).unwrap();
    value["schema"] = "urn:endor:ast:unknown".into();
    assert!(matches!(
        AstDocument::from_json(&value.to_string()),
        Err(AstError::SchemaMismatch { .. })
    ));
    value = serde_json::to_value(&document).unwrap();
    value["root"]["data"]["unexpected"] = true.into();
    assert!(matches!(
        AstDocument::from_json(&value.to_string()),
        Err(AstError::Json(_))
    ));
    value = serde_json::to_value(&document).unwrap();
    value["root"]["data"]["span"]["end"] = 1.into();
    assert!(matches!(
        AstDocument::from_json(&value.to_string()),
        Err(AstError::ChildOutsideParent { .. })
    ));
    let AstRoot::Expression(mut expression) = document.root else {
        unreachable!()
    };
    expression.span = Span::new(5, 4);
    assert!(matches!(
        AstDocument::new(AstRoot::Expression(expression)),
        Err(AstError::InvalidSpan(_))
    ));
    let root = AstRoot::Expression(Expr {
        kind: ExprKind::Name("値".into()),
        span: Span::new(1, 3),
    });
    assert!(matches!(
        AstDocument::new(root).unwrap().validate_source("値"),
        Err(AstError::InvalidSpan(_))
    ));
}

#[test]
fn bare_assignment_has_its_own_ast_and_unicode_source_ranges() {
    let source = "标题 = ui.text(\"你好\")";
    let root = parse_ast(source, ParseMode::Interactive).unwrap();
    let AstRoot::Interactive(input) = &root else {
        panic!("interactive input")
    };
    let StmtKind::Assignment(assignment) = &input.statements[0].kind else {
        panic!("assignment")
    };
    assert_eq!(assignment.name.text, "标题");
    assert_eq!(assignment.name.source_text(source), Some("标题"));
    assert_eq!(assignment.source_text(source), Some(source));
    let document = AstDocument::new(root).unwrap();
    document.validate_source(source).unwrap();
    let json = document.to_json().unwrap();
    assert_eq!(AstDocument::from_json(&json).unwrap(), document);
    assert!(parse_ast("value = 1 = 2", ParseMode::Interactive).is_err());
    let member = parse_ast("object.field = 1", ParseMode::Interactive).unwrap();
    let AstRoot::Interactive(member) = member else {
        panic!("interactive")
    };
    assert!(matches!(
        &member.statements[0].kind,
        StmtKind::MemberAssignment(_)
    ));
    assert!(parse_ast("object() = 1", ParseMode::Interactive).is_err());
}