// Charter Language Grammar (Pest Parser)
// NAC原生智能合约语言语法定义

WHITESPACE = _{ " " | "\t" | "\r" | "\n" }
COMMENT = _{ "//" ~ (!"\n" ~ ANY)* ~ "\n" | "/*" ~ (!"*/" ~ ANY)* ~ "*/" }

// ============================================================================
// 基础类型
// ============================================================================

// 标识符
identifier = @{ (ASCII_ALPHA | "_") ~ (ASCII_ALPHANUMERIC | "_")* }

// 字面量
integer = @{ ASCII_DIGIT+ }
hex_number = @{ "0x" ~ ASCII_HEX_DIGIT+ }
string_literal = @{ "\"" ~ (!"\"" ~ ANY)* ~ "\"" }
boolean = @{ "true" | "false" }

// GNACS编码 (48位十六进制)
gnacs_code = @{ "0x" ~ ASCII_HEX_DIGIT{12} }

// DID标识符
did = @{ "did:nac:" ~ identifier ~ ":" ~ identifier ~ ":" ~ (ASCII_ALPHANUMERIC | "_")+ }

// ============================================================================
// 类型系统
// ============================================================================

primitive_type = {
    "uint8" | "uint16" | "uint32" | "uint64" | "uint128" | "uint256" |
    "int8" | "int16" | "int32" | "int64" | "int128" | "int256" |
    "bool" | "string" | "bytes" | "address" | "hash" | "timestamp"
}

nac_type = {
    "DID" | "GNACSCode" | "ConstitutionalReceipt" | "AssetInstance" |
    "ACC20" | "ACC721" | "ACC1155" | "ACCRWA"
}

array_type = { (primitive_type | nac_type) ~ "[" ~ integer? ~ "]" }

type_annotation = { primitive_type | nac_type | array_type }

// ============================================================================
// 资产定义
// ============================================================================

asset_definition = {
    "asset" ~ identifier ~ "{" ~
        gnacs_declaration ~
        sovereignty_declaration? ~
        asset_fields ~
        asset_methods? ~
    "}"
}

gnacs_declaration = {
    "gnacs" ~ ":" ~ gnacs_code ~ ";"
}

sovereignty_declaration = {
    "sovereignty" ~ ":" ~ sovereignty_type ~ ";"
}

sovereignty_type = {
    "A0" | "C0" | "C1" | "C2" | "D0" | "D1" | "D2"
}

asset_fields = {
    (field_declaration ~ ";")*
}

field_declaration = {
    identifier ~ ":" ~ type_annotation
}

asset_methods = {
    (method_declaration)*
}

// ============================================================================
// 合约定义
// ============================================================================

contract_definition = {
    "contract" ~ identifier ~ "{" ~
        contract_fields ~
        contract_methods ~
    "}"
}

contract_fields = {
    (field_declaration ~ ";")*
}

contract_methods = {
    (method_declaration)*
}

method_declaration = {
    method_modifiers? ~
    "fn" ~ identifier ~ "(" ~ parameter_list? ~ ")" ~
    ("->" ~ type_annotation)? ~
    requires_clause? ~
    ensures_clause? ~
    method_body
}

method_modifiers = {
    ("public" | "private" | "internal" | "payable" | "view" | "pure")+
}

parameter_list = {
    parameter ~ ("," ~ parameter)*
}

parameter = {
    identifier ~ ":" ~ type_annotation
}

// ============================================================================
// 宪法约束（前置/后置条件）
// ============================================================================

requires_clause = {
    "requires" ~ "{" ~ expression_list ~ "}"
}

ensures_clause = {
    "ensures" ~ "{" ~ expression_list ~ "}"
}

expression_list = {
    (expression ~ ";")*
}

// ============================================================================
// 方法体
// ============================================================================

method_body = {
    "{" ~ statement* ~ "}"
}

statement = {
    let_statement |
    assign_statement |
    if_statement |
    for_statement |
    while_statement |
    return_statement |
    emit_statement |
    cr_statement |
    expression_statement
}

let_statement = {
    "let" ~ identifier ~ (":" ~ type_annotation)? ~ "=" ~ expression ~ ";"
}

assign_statement = {
    identifier ~ "=" ~ expression ~ ";"
}

if_statement = {
    "if" ~ expression ~ method_body ~ ("else" ~ method_body)?
}

for_statement = {
    "for" ~ identifier ~ "in" ~ expression ~ method_body
}

while_statement = {
    "while" ~ expression ~ method_body
}

return_statement = {
    "return" ~ expression? ~ ";"
}

emit_statement = {
    "emit" ~ identifier ~ "(" ~ argument_list? ~ ")" ~ ";"
}

// 宪法收据相关语句
cr_statement = {
    "require_cr" ~ "(" ~ expression ~ ")" ~ ";" |
    "verify_cr" ~ "(" ~ expression ~ ")" ~ ";"
}

expression_statement = {
    expression ~ ";"
}

// ============================================================================
// 表达式
// ============================================================================

expression = {
    logical_or_expr
}

logical_or_expr = {
    logical_and_expr ~ ("||" ~ logical_and_expr)*
}

logical_and_expr = {
    equality_expr ~ ("&&" ~ equality_expr)*
}

equality_expr = {
    relational_expr ~ (("==" | "!=") ~ relational_expr)*
}

relational_expr = {
    additive_expr ~ (("<" | ">" | "<=" | ">=") ~ additive_expr)*
}

additive_expr = {
    multiplicative_expr ~ (("+" | "-") ~ multiplicative_expr)*
}

multiplicative_expr = {
    unary_expr ~ (("*" | "/" | "%") ~ unary_expr)*
}

unary_expr = {
    ("!" | "-") ~ unary_expr |
    primary_expr
}

primary_expr = {
    integer |
    hex_number |
    string_literal |
    boolean |
    gnacs_code |
    did |
    identifier |
    function_call |
    member_access |
    array_access |
    "(" ~ expression ~ ")"
}

function_call = {
    identifier ~ "(" ~ argument_list? ~ ")"
}

argument_list = {
    expression ~ ("," ~ expression)*
}

member_access = {
    identifier ~ ("." ~ identifier)+
}

array_access = {
    identifier ~ "[" ~ expression ~ "]"
}

// ============================================================================
// 顶层定义
// ============================================================================

module_definition = {
    "module" ~ identifier ~ ";"
}

import_statement = {
    "import" ~ string_literal ~ ";"
}

top_level_item = {
    module_definition |
    import_statement |
    asset_definition |
    contract_definition
}

// ============================================================================
// 程序入口
// ============================================================================

program = {
    SOI ~ top_level_item* ~ EOI
}