import { Span } from "../diagnostics.ts";

export type File = {
    stmts: Stmt[];
};

export type Stmt = {
    kind: StmtKind;
    span: Span;
};

export type StmtKind =
    | { tag: "error" }
    | { tag: "item" } & ItemStmt
    | { tag: "let" } & LetStmt
    | { tag: "return" } & ReturnStmt
    | { tag: "break" } & BreakStmt
    | { tag: "assign" } & AssignStmt
    | { tag: "expr" } & ExprStmt;

export type ItemStmt = { item: Item };

export type LetStmt = {
    subject: Pat;
    expr?: Expr;
};

export type ReturnStmt = { expr?: Expr };
export type BreakStmt = { expr?: Expr };

export type AssignStmt = {
    assignType: AssignType;
    subject: Expr;
    value: Expr;
};

export type AssignType = "=" | "+=" | "-=";

export type ExprStmt = { expr: Expr };

export type Item = {
    kind: ItemKind;
    span: Span;
    ident: Ident;
    pub: boolean;
};

export type ItemKind =
    | { tag: "error" }
    | { tag: "mod_block" } & ModBlockItem
    | { tag: "mod_file" } & ModFileItem
    | { tag: "enum" } & EnumItem
    | { tag: "struct" } & StructItem
    | { tag: "fn" } & FnItem
    | { tag: "use" } & UseItem
    | { tag: "static" } & StaticItem
    | { tag: "type_alias" } & TypeAliasItem;

export type ModBlockItem = {
    ident: Ident;
    stmts: Stmt[];
};

export type ModFileItem = {
    ident: Ident;
    filePath: string;
};

export type EnumItem = { variants: Variant[] };
export type StructItem = { data: VariantData };
export type FnItem = { _: 0 };
export type UseItem = { _: 0 };
export type StaticItem = { _: 0 };
export type TypeAliasItem = { _: 0 };

export type Variant = {
    ident: Ident;
    data: VariantData;
    pub: boolean;
    span: Span;
};

export type VariantData = {
    kind: VariantDataKind;
    span: Span;
};

export type VariantDataKind =
    | { tag: "error" }
    | { tag: "unit" }
    | { tag: "tuple" } & TupleVariantData
    | { tag: "struct" } & StructVariantData;

export type TupleVariantData = { elems: VariantData[] };
export type StructVariantData = { fields: FieldDef[] };

export type FieldDef = {
    ident: Ident;
    ty: Ty;
    pub: boolean;
    span: Span;
};

export type Expr = {
    kind: ExprKind;
    span: Span;
};

export type ExprKind =
    | { tag: "error" }
    | { tag: "ident" } & Ident;

export type Pat = {
    kind: PatKind;
    span: Span;
};

export type PatKind =
    | { tag: "error" }
    | { tag: "bind" } & BindPat;

export type BindPat = {
    ident: Ident;
    mut: boolean;
};

export type Ty = {
    kind: TyKind;
    span: Span;
};

export type TyKind =
    | { tag: "error" }
    | { tag: "ident" } & Ident
    | { tag: "ref" } & RefTy
    | { tag: "ptr" } & PtrTy
    | { tag: "slice" } & SliceTy
    | { tag: "array" } & ArrayTy;

export type RefTy = { ty: Ty; mut: boolean };
export type PtrTy = { ty: Ty; mut: boolean };
export type SliceTy = { ty: Ty };
export type ArrayTy = { ty: Ty; length: Expr };
export type TupleTy = { elems: Ty[] };
export type StructTy = { fields: FieldDef[] };

export type AnonFieldDef = {
    ident: Ident;
    ty: Ty;
    span: Span;
};

export type Ident = { text: string; span: Span };