vyre-libs 0.6.1

use crate::parsing::c::lex::tokens::*;
use vyre::ir::{Expr, Node};

mod predicates;
use super::scan::{
    emit_forward_matching_paren_scan, emit_post_paren_boundary_scan,
    emit_reverse_unmatched_lbrace_scan,
};
use predicates::{declaration_context, tag_keyword};

/// No declaration kind.
pub const DECL_KIND_NONE: u32 = 0;
/// Function definition declaration kind.
pub const DECL_KIND_FUNCTION: u32 = 1;
/// Function prototype declaration kind.
pub const DECL_KIND_FUNCTION_DECL: u32 = 2;
/// Variable declaration kind.
pub const DECL_KIND_VARIABLE: u32 = 3;
/// Label declaration kind.
pub const DECL_KIND_LABEL: u32 = 4;
/// Typedef declaration kind.
pub const DECL_KIND_TYPEDEF: u32 = 5;
/// Enum constant declaration kind.
pub const DECL_KIND_ENUM_CONSTANT: u32 = 6;

fn emit_neighbor_tokens(node_idx: &Expr, num_tokens: &Expr) -> Vec<Node> {
    vec![
        Node::let_bind("prev_prev_tok", Expr::u32(0)),
        Node::if_then(
            Expr::gt(node_idx.clone(), Expr::u32(1)),
            vec![Node::assign(
                "prev_prev_tok",
                Expr::load("tok_types", Expr::sub(node_idx.clone(), Expr::u32(2))),
            )],
        ),
        Node::let_bind("next_next_tok", Expr::u32(0)),
        Node::if_then(
            Expr::lt(
                Expr::add(node_idx.clone(), Expr::u32(2)),
                num_tokens.clone(),
            ),
            vec![Node::assign(
                "next_next_tok",
                Expr::load("tok_types", Expr::add(node_idx.clone(), Expr::u32(2))),
            )],
        ),
    ]
}

fn emit_aggregate_context(node_idx: &Expr) -> Vec<Node> {
    let mut nodes = vec![
        Node::let_bind("aggregate_kind", Expr::u32(0)),
        Node::let_bind("aggregate_open", Expr::u32(u32::MAX)),
        Node::let_bind("aggregate_depth", Expr::u32(0)),
    ];
    nodes.extend(emit_reverse_unmatched_lbrace_scan(
        "tok_types",
        "aggregate_scan",
        "aggregate_idx",
        "aggregate_tok",
        "aggregate_depth",
        "aggregate_open",
        node_idx.clone(),
        Some(Expr::eq(Expr::var("tok_type"), Expr::u32(TOK_IDENTIFIER))),
    ));
    let mut aggregate_body = vec![Node::let_bind("aggregate_idx", Expr::var("aggregate_open"))];
    aggregate_body.extend(emit_set_aggregate_kind());
    nodes.push(Node::if_then(
        Expr::and(
            Expr::eq(Expr::var("tok_type"), Expr::u32(TOK_IDENTIFIER)),
            Expr::ne(Expr::var("aggregate_open"), Expr::u32(u32::MAX)),
        ),
        aggregate_body,
    ));
    nodes
}

fn emit_set_aggregate_kind() -> Vec<Node> {
    vec![
        Node::let_bind("aggregate_prev", Expr::u32(0)),
        Node::let_bind("aggregate_prev_prev", Expr::u32(0)),
        Node::if_then(
            Expr::gt(Expr::var("aggregate_idx"), Expr::u32(0)),
            vec![Node::assign(
                "aggregate_prev",
                Expr::load(
                    "tok_types",
                    Expr::sub(Expr::var("aggregate_idx"), Expr::u32(1)),
                ),
            )],
        ),
        Node::if_then(
            Expr::gt(Expr::var("aggregate_idx"), Expr::u32(1)),
            vec![Node::assign(
                "aggregate_prev_prev",
                Expr::load(
                    "tok_types",
                    Expr::sub(Expr::var("aggregate_idx"), Expr::u32(2)),
                ),
            )],
        ),
        Node::if_then(
            tag_keyword(Expr::var("aggregate_prev")),
            vec![Node::assign("aggregate_kind", Expr::var("aggregate_prev"))],
        ),
        Node::if_then(
            Expr::and(
                Expr::eq(Expr::var("aggregate_kind"), Expr::u32(0)),
                tag_keyword(Expr::var("aggregate_prev_prev")),
            ),
            vec![Node::assign(
                "aggregate_kind",
                Expr::var("aggregate_prev_prev"),
            )],
        ),
    ]
}

fn emit_declaration_flags(node_idx: &Expr) -> Vec<Node> {
    vec![
        Node::let_bind("seen_typedef_in_decl", Expr::u32(0)),
        Node::let_bind("decl_prefix_active", Expr::u32(1)),
        Node::if_then(
            Expr::eq(Expr::var("tok_type"), Expr::u32(TOK_IDENTIFIER)),
            vec![Node::loop_for(
                "decl_prefix_scan",
                Expr::u32(0),
                node_idx.clone(),
                vec![
                    Node::let_bind(
                        "decl_prefix_idx",
                        Expr::sub(
                            Expr::sub(node_idx.clone(), Expr::u32(1)),
                            Expr::var("decl_prefix_scan"),
                        ),
                    ),
                    Node::let_bind(
                        "decl_prefix_tok",
                        Expr::load("tok_types", Expr::var("decl_prefix_idx")),
                    ),
                    Node::if_then(
                        Expr::and(
                            Expr::eq(Expr::var("decl_prefix_active"), Expr::u32(1)),
                            Expr::eq(Expr::var("decl_prefix_tok"), Expr::u32(TOK_TYPEDEF)),
                        ),
                        vec![Node::assign("seen_typedef_in_decl", Expr::u32(1))],
                    ),
                    Node::if_then(
                        Expr::and(
                            Expr::eq(Expr::var("decl_prefix_active"), Expr::u32(1)),
                            Expr::or(
                                Expr::eq(Expr::var("decl_prefix_tok"), Expr::u32(TOK_SEMICOLON)),
                                Expr::eq(Expr::var("decl_prefix_tok"), Expr::u32(TOK_LBRACE)),
                            ),
                        ),
                        vec![Node::assign("decl_prefix_active", Expr::u32(0))],
                    ),
                ],
            )],
        ),
    ]
}

fn emit_function_declarator_after_lparen(node_idx: &Expr, num_tokens: &Expr) -> Node {
    let mut body = emit_forward_matching_paren_scan(
        "tok_types",
        "paren_idx",
        Expr::add(node_idx.clone(), Expr::u32(2)),
        num_tokens.clone(),
        "paren_tok",
        "paren_depth",
        "matching_rparen",
        Some(Expr::lt(
            Expr::add(node_idx.clone(), Expr::u32(2)),
            num_tokens.clone(),
        )),
    );
    body.push(Node::if_then(
        Expr::ne(Expr::var("matching_rparen"), Expr::u32(u32::MAX)),
        {
            let mut after_paren = emit_post_paren_boundary_scan(
                "tok_types",
                "after_paren_scan",
                "after_scan_tok",
                "after_scan_active",
                Expr::var("matching_rparen"),
                num_tokens.clone(),
                "after_matching_paren",
                "after_matching_paren_idx",
            );
            after_paren.push(Node::if_then_else(
                Expr::eq(Expr::var("after_matching_paren"), Expr::u32(TOK_LBRACE)),
                vec![Node::assign("decl_kind", Expr::u32(DECL_KIND_FUNCTION))],
                vec![Node::if_then_else(
                    declaration_context(Expr::var("prev_tok")),
                    vec![Node::if_then_else(
                        Expr::eq(Expr::var("prev_tok"), Expr::u32(TOK_TYPEDEF)),
                        vec![Node::assign("decl_kind", Expr::u32(DECL_KIND_TYPEDEF))],
                        vec![Node::assign(
                            "decl_kind",
                            Expr::u32(DECL_KIND_FUNCTION_DECL),
                        )],
                    )],
                    vec![Node::if_then(
                        Expr::eq(Expr::var("prev_tok"), Expr::u32(TOK_TYPEDEF)),
                        vec![Node::assign("decl_kind", Expr::u32(DECL_KIND_TYPEDEF))],
                    )],
                )],
            ));
            after_paren
        },
    ));
    Node::if_then(Expr::eq(Expr::var("next_tok"), Expr::u32(TOK_LPAREN)), body)
}

/// Emit IR that classifies the declaration kind around `node_idx`.
pub fn emit_declaration_lookup(node_idx: Expr, num_tokens: &Expr) -> Vec<Node> {
    let mut nodes = vec![
        Node::let_bind("decl_kind", Expr::u32(DECL_KIND_NONE)),
        Node::let_bind("prev_idx", Expr::u32(u32::MAX)),
        Node::let_bind("next_idx", Expr::u32(u32::MAX)),
        Node::let_bind("prev_tok", Expr::u32(0)),
        Node::let_bind("next_tok", Expr::u32(0)),
    ];

    nodes.push(Node::if_then(
        Expr::gt(node_idx.clone(), Expr::u32(0)),
        vec![Node::assign(
            "prev_idx",
            Expr::sub(node_idx.clone(), Expr::u32(1)),
        )],
    ));
    nodes.push(Node::if_then(
        Expr::lt(
            Expr::add(node_idx.clone(), Expr::u32(1)),
            num_tokens.clone(),
        ),
        vec![Node::assign(
            "next_idx",
            Expr::add(node_idx.clone(), Expr::u32(1)),
        )],
    ));

    nodes.push(Node::if_then(
        Expr::ne(Expr::var("prev_idx"), Expr::u32(u32::MAX)),
        vec![Node::assign(
            "prev_tok",
            Expr::load("tok_types", Expr::var("prev_idx")),
        )],
    ));
    nodes.push(Node::if_then(
        Expr::ne(Expr::var("next_idx"), Expr::u32(u32::MAX)),
        vec![Node::assign(
            "next_tok",
            Expr::load("tok_types", Expr::var("next_idx")),
        )],
    ));
    nodes.extend(emit_neighbor_tokens(&node_idx, num_tokens));
    nodes.extend(emit_aggregate_context(&node_idx));
    nodes.extend(emit_declaration_flags(&node_idx));

    nodes.push(Node::if_then(
        Expr::eq(Expr::var("tok_type"), Expr::u32(TOK_IDENTIFIER)),
        vec![Node::if_then_else(
            Expr::and(
                Expr::eq(Expr::var("next_tok"), Expr::u32(TOK_COLON)),
                Expr::and(
                    Expr::ne(Expr::var("prev_tok"), Expr::u32(TOK_CASE)),
                    Expr::ne(Expr::var("prev_tok"), Expr::u32(TOK_GOTO)),
                ),
            ),
            vec![Node::assign("decl_kind", Expr::u32(DECL_KIND_LABEL))],
            vec![Node::if_then_else(
                tag_keyword(Expr::var("prev_tok")),
                vec![Node::assign("decl_kind", Expr::u32(DECL_KIND_NONE))],
                vec![Node::if_then_else(
                    Expr::and(
                        Expr::eq(Expr::var("aggregate_kind"), Expr::u32(TOK_ENUM)),
                        Expr::or(
                            Expr::or(
                                Expr::eq(Expr::var("prev_tok"), Expr::u32(TOK_LBRACE)),
                                Expr::eq(Expr::var("prev_tok"), Expr::u32(TOK_COMMA)),
                            ),
                            Expr::or(
                                Expr::eq(Expr::var("next_tok"), Expr::u32(TOK_COMMA)),
                                Expr::or(
                                    Expr::eq(Expr::var("next_tok"), Expr::u32(TOK_ASSIGN)),
                                    Expr::eq(Expr::var("next_tok"), Expr::u32(TOK_RBRACE)),
                                ),
                            ),
                        ),
                    ),
                    vec![Node::assign(
                        "decl_kind",
                        Expr::u32(DECL_KIND_ENUM_CONSTANT),
                    )],
                    vec![Node::if_then_else(
                        Expr::and(
                            Expr::ne(Expr::var("aggregate_kind"), Expr::u32(0)),
                            Expr::ne(Expr::var("aggregate_kind"), Expr::u32(TOK_ENUM)),
                        ),
                        vec![Node::assign("decl_kind", Expr::u32(DECL_KIND_NONE))],
                        vec![
                            emit_function_declarator_after_lparen(&node_idx, num_tokens),
                            Node::if_then_else(
                                Expr::eq(Expr::var("decl_kind"), Expr::u32(DECL_KIND_NONE)),
                                vec![Node::if_then_else(
                                    Expr::or(
                                        Expr::eq(Expr::var("prev_tok"), Expr::u32(TOK_TYPEDEF)),
                                        Expr::eq(Expr::var("seen_typedef_in_decl"), Expr::u32(1)),
                                    ),
                                    vec![Node::assign("decl_kind", Expr::u32(DECL_KIND_TYPEDEF))],
                                    vec![Node::if_then(
                                        declaration_context(Expr::var("prev_tok")),
                                        vec![Node::assign(
                                            "decl_kind",
                                            Expr::u32(DECL_KIND_VARIABLE),
                                        )],
                                    )],
                                )],
                                vec![],
                            ),
                        ],
                    )],
                )],
            )],
        )],
    ));

    nodes
}