"""
Dana Dana AST (Abstract Syntax Tree)

This module defines the AST (Abstract Syntax Tree) structures for the Dana language in Dana.

Copyright © 2025 Aitomatic, Inc.
MIT License

Community Values:
    1. Attribution: Please maintain attribution to Aitomatic and Dana/Dana in derivative works.
    2. Contributions: If you find Dana/Dana valuable, consider contributing improvements back rather than creating separate, similar implementations.
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Learn more: https://aitomatic.com
GitHub: https://github.com/aitomatic/dana
Discord: https://discord.gg/6jGD4PYk
"""

from dataclasses import dataclass, field
from enum import Enum
from typing import Any, Optional, Protocol, Union


# Define a protocol instead of a base class to avoid dataclass inheritance issues
class ASTNode(Protocol):
    """Protocol for all AST nodes in Dana."""

    location: Optional["Location"]

    def evaluate(self, context) -> Any:
        """Every node can be evaluated to produce a value."""
        ...


# === Type Aliases ===
# An Expression is any node that primarily produces a value.
Expression = Union[
    "LiteralExpression",
    "Identifier",
    "BinaryExpression",
    "ConditionalExpression",
    "FunctionCall",
    "ObjectFunctionCall",
    "FStringExpression",
    "UnaryExpression",
    "AttributeAccess",
    "SubscriptExpression",
    "SliceExpression",
    "SliceTuple",
    "DictLiteral",
    "ListLiteral",
    "SetLiteral",
    "TupleLiteral",
    "StructLiteral",
    "PlaceholderExpression",
    "PipelineExpression",
    "LambdaExpression",
    "ListComprehension",
    "SetComprehension",
    "DictComprehension",
]

# A Statement is any node that primarily performs an action, but still produces a value.
Statement = Union[
    "Assignment",
    "CompoundAssignment",  # Compound assignments like x += 1
    "Conditional",
    "WhileLoop",
    "ForLoop",
    "TryBlock",
    "FunctionDefinition",
    "MethodDefinition",
    "DeclarativeFunctionDefinition",  # Declarative function definitions
    "StructDefinition",
    "InterfaceDefinition",
    "ResourceDefinition",
    "AgentDefinition",
    "ImportStatement",
    "ImportFromStatement",
    "FunctionCall",  # Can be both an expression and a statement
    "ObjectFunctionCall",  # Can also be both an expression and a statement
    "BreakStatement",
    "ContinueStatement",
    "PassStatement",
    "ReturnStatement",
    "RaiseStatement",
    "AssertStatement",
    Expression,  # Any expression can be used as a statement
]


# === Enums ===
class BinaryOperator(Enum):
    """Binary operators supported in Dana."""

    EQUALS = "=="
    NOT_EQUALS = "!="
    LESS_THAN = "<"
    GREATER_THAN = ">"
    LESS_EQUALS = "<="
    GREATER_EQUALS = ">="
    AND = "and"
    OR = "or"
    IN = "in"
    NOT_IN = "not in"
    IS = "is"
    IS_NOT = "is not"
    ADD = "+"
    SUBTRACT = "-"
    MULTIPLY = "*"
    DIVIDE = "/"
    FLOOR_DIVIDE = "//"
    MODULO = "%"
    POWER = "**"
    PIPE = "|"


# === Utility Classes ===
@dataclass(frozen=True)
class Location:
    """Source code location (line, column, source)."""

    line: int
    column: int
    source: str


@dataclass
class TypeHint:
    """A type annotation (e.g., int, str, list, dict)."""

    name: str  # The type name (int, str, list, dict, etc.)
    location: Location | None = None


@dataclass
class Parameter:
    """A function parameter with optional type hint."""

    name: str
    type_hint: TypeHint | None = None
    default_value: Expression | None = None
    location: Location | None = None


@dataclass
class LambdaExpression:
    """A lambda expression with optional receiver and parameters."""

    receiver: Parameter | None = None  # Optional struct receiver: (receiver: Type)
    parameters: list[Parameter] = field(default_factory=list)  # Lambda parameters
    body: Expression | None = None  # Lambda body expression
    location: Location | None = None


@dataclass
class ListComprehension:
    """A list comprehension expression (e.g., [x * 2 for x in numbers if x > 0])."""

    expression: Expression  # The expression to evaluate for each item
    target: str  # The variable name for each item (e.g., 'x')
    iterable: Expression  # The iterable to iterate over
    condition: Expression | None = None  # Optional condition (e.g., 'x > 0')
    location: Location | None = None


@dataclass
class SetComprehension:
    """A set comprehension expression (e.g., {x * 2 for x in numbers if x > 0})."""

    expression: Expression  # The expression to evaluate for each item
    target: str  # The variable name for each item (e.g., 'x')
    iterable: Expression  # The iterable to iterate over
    condition: Expression | None = None  # Optional condition (e.g., 'x > 0')
    location: Location | None = None


@dataclass
class DictComprehension:
    """A dict comprehension expression (e.g., {k: v * 2 for k, v in data.items() if v > 0})."""

    key_expr: Expression  # The key expression to evaluate for each item
    value_expr: Expression  # The value expression to evaluate for each item
    target: str  # The variable name for each item (e.g., 'k, v')
    iterable: Expression  # The iterable to iterate over
    condition: Expression | None = None  # Optional condition (e.g., 'v > 0')
    location: Location | None = None


# === Literals and Identifiers ===
@dataclass
class LiteralExpression:
    """A literal value (int, float, string, bool, None, list, or f-string)."""

    value: Union[int, float, str, bool, None, "FStringExpression", list[Any]]
    location: Location | None = None

    @property
    def type(self):
        if isinstance(self.value, bool):
            return "bool"
        elif isinstance(self.value, str):
            return "string"
        elif isinstance(self.value, int):
            return "int"
        elif isinstance(self.value, float):
            return "float"
        elif self.value is None:
            return "null"
        elif hasattr(self.value, "__class__") and self.value.__class__.__name__ == "FStringExpression":
            return "string"
        elif isinstance(self.value, list):
            return "array"
        else:
            return "any"


@dataclass
class FStringExpression:
    """An f-string with embedded expressions."""

    parts: list[str | Expression]  # Literal strings or expressions
    location: Location | None = None
    template: str = ""
    expressions: dict[str, Expression] = field(default_factory=dict)


@dataclass
class Identifier:
    """A variable, function, or module name."""

    name: str
    location: Location | None = None


# === Expressions ===
@dataclass
class PlaceholderExpression:
    """A placeholder expression representing the $$ symbol in pipeline operations."""

    location: Location | None = None


@dataclass
class NamedPipelineStage:
    """A pipeline stage with an optional name capture (expr as name)."""

    expression: Expression
    name: str | None = None  # If present, capture result with this name
    location: Location | None = None


@dataclass
class PipelineExpression:
    """A pipeline expression representing function composition via the | operator."""

    stages: list[Expression]
    location: Location | None = None


@dataclass
class UnaryExpression:
    """A unary operation (e.g., -x, not y)."""

    operator: str  # e.g., '-', 'not'
    operand: Expression
    location: Location | None = None


@dataclass
class BinaryExpression:
    """A binary operation (e.g., x + y, a and b)."""

    left: Expression
    operator: BinaryOperator
    right: Expression
    location: Location | None = None


@dataclass
class ConditionalExpression:
    """A conditional expression (e.g., x if condition else y)."""

    condition: Expression
    true_branch: Expression
    false_branch: Expression
    location: Location | None = None


@dataclass
class FunctionCall:
    """A function call (e.g., foo(1, 2)), can be used as either expression or statement."""

    name: Union[str, "AttributeAccess"]  # Function name or AttributeAccess for method calls
    args: dict[str, Any]
    location: Location | None = None


@dataclass
class ObjectFunctionCall:
    """An object method call (e.g., obj.method(args)).


    This AST node represents calling a method on an object, which is different from
    accessing an attribute or calling a standalone function. It handles expressions
    like `websearch.list_tools()`, `obj.method(arg1, arg2)`, etc.


    The ObjectFunctionCall distinguishes between:
    - The target object (which can be any expression that evaluates to an object)
    - The method name (a string identifier)
    - The arguments passed to the method call


    This enables Dana to support object-oriented programming patterns and method
    chaining while maintaining clear separation between attribute access and
    method invocation.


    Examples:
        - `websearch.list_tools()` - call list_tools method on websearch object
        - `obj.add(10)` - call add method with argument 10
        - `api.get_data("users")` - call get_data method with string argument


    Attributes:
        object: The target object expression to call the method on
        method_name: The name of the method to call (string)
        args: Dictionary of arguments (positional and keyword) to pass to the method
        location: Optional source location for error reporting
    """

    object: Expression  # The object on which to call the method
    method_name: str  # The method name
    args: dict[str, Any]  # Arguments to the method
    location: Location | None = None


@dataclass
class AttributeAccess:
    """Attribute access (e.g., obj.attr)."""

    object: Expression
    attribute: str
    location: Location | None = None


@dataclass
class SliceExpression:
    """A slice expression (e.g., start:end:step)."""

    start: Expression | None = None
    stop: Expression | None = None
    step: Expression | None = None
    location: Location | None = None


@dataclass
class SliceTuple:
    """A tuple of slice expressions for multi-dimensional slicing (e.g., obj[0:2, 1:4])."""

    slices: list[Expression | SliceExpression]  # List of slice expressions or regular expressions
    location: Location | None = None


@dataclass
class SubscriptExpression:
    """Indexing/subscription (e.g., a[0], a["key"]) or slicing (e.g., a[0:2]) or multi-dimensional slicing (e.g., a[0:2, 1:4])."""

    object: Expression
    index: Expression | SliceExpression | SliceTuple  # Can be index, single slice, or multi-dimensional slice
    location: Location | None = None


@dataclass
class TupleLiteral:
    """A tuple literal (e.g., (1, 2))."""

    items: list[Expression]
    location: Location | None = None


@dataclass
class DictLiteral:
    """A dictionary literal (e.g., {"k": v})."""

    items: list[tuple[Expression, Expression]]
    location: Location | None = None


@dataclass
class SetLiteral:
    """A set literal (e.g., {1, 2, 3})."""

    items: list[Expression]
    location: Location | None = None


@dataclass
class ListLiteral:
    """A list literal (e.g., [1, 2, 3])."""

    items: list[Expression]
    location: Location | None = None


# === Statements ===
@dataclass
class Assignment:
    """Assignment statement (e.g., x = 42, obj[key] = value, obj.attr = value). Returns the assigned value."""

    target: Identifier | SubscriptExpression | AttributeAccess  # Allow complex assignment targets
    value: Union[
        LiteralExpression,
        Identifier,
        BinaryExpression,
        UnaryExpression,
        FunctionCall,
        ObjectFunctionCall,
        TupleLiteral,
        DictLiteral,
        ListLiteral,
        SetLiteral,
        SubscriptExpression,
        AttributeAccess,
        FStringExpression,
        "DeclarativeFunctionDefinition",  # Added to support declarative function definitions
    ]
    type_hint: TypeHint | None = None  # For typed assignments like x: int = 42
    location: Location | None = None


@dataclass
class CompoundAssignment:
    """Compound assignment statement (e.g., x += 1, obj.attr *= 2). Returns the assigned value."""

    target: Identifier | SubscriptExpression | AttributeAccess  # Same targets as Assignment
    operator: str  # "+=" | "-=" | "*=" | "/="
    value: Expression  # Right-hand side expression
    location: Location | None = None


@dataclass
class Conditional:
    """If/elif/else conditional statement. Returns the value of the last executed statement."""

    condition: Expression
    body: list[Union[Assignment, "Conditional", "WhileLoop", FunctionCall, "ObjectFunctionCall"]]
    line_num: int  # Line number where this conditional was defined
    else_body: list[Union[Assignment, "Conditional", "WhileLoop", FunctionCall, "ObjectFunctionCall"]] = field(default_factory=list)
    location: Location | None = None


@dataclass
class WhileLoop:
    """While loop statement."""

    condition: Expression
    body: list[Union[Assignment, "Conditional", "WhileLoop", FunctionCall, "ObjectFunctionCall"]]
    line_num: int
    location: Location | None = None


@dataclass
class ForLoop:
    """For loop statement."""

    target: Union[Identifier, list[Identifier]]  # Support single or multiple targets for tuple unpacking
    iterable: Expression
    body: list[Statement]
    location: Location | None = None


@dataclass
class TryBlock:
    """Try/except/finally block."""

    body: list[Statement]
    except_blocks: list["ExceptBlock"]
    finally_block: list[Statement] | None = None
    location: Location | None = None


@dataclass
class ExceptBlock:
    """Except block for try/except."""

    body: list[Statement]
    location: Location | None = None
    exception_type: Expression | None = None  # Can be Identifier, TupleLiteral, or None
    variable_name: str | None = None  # Variable name from 'as' clause


@dataclass
class WithStatement:
    """With statement (e.g., with mcp('hi') as foo: ... or with mcp_object as foo: ...)."""

    context_manager: str | Expression  # Either function name (str) or context manager object (Expression)
    args: list[Expression]  # Empty when using direct object
    kwargs: dict[str, Expression]  # Empty when using direct object
    as_var: str
    body: list[Statement]
    location: Location | None = None


@dataclass
class FunctionDefinition:
    """Function definition statement (unified for both regular functions and methods)."""

    name: Identifier
    parameters: list[Parameter]
    body: list[Statement]
    return_type: TypeHint | None = None
    decorators: list["Decorator"] = field(default_factory=list)  # Decorators applied to function
    is_sync: bool = False  # NEW FIELD: indicates if function should execute synchronously
    receiver: Parameter | None = None  # Optional receiver parameter for methods
    location: Location | None = None


@dataclass
class MethodDefinition:
    """Method definition statement with explicit receiver (e.g., def (point: Point) translate(dx, dy):)."""

    receiver: Parameter  # The receiver parameter (e.g., point: Point)
    name: Identifier  # Method name
    parameters: list[Parameter]  # Regular parameters (excluding receiver)
    body: list[Statement]
    return_type: TypeHint | None = None
    decorators: list["Decorator"] = field(default_factory=list)
    is_sync: bool = False  # NEW FIELD: indicates if method should execute synchronously
    location: Location | None = None


@dataclass
class DeclarativeFunctionDefinition:
    """Declarative function definition statement (e.g., def func(x: int) -> str = f1 | f2)."""

    name: Identifier
    parameters: list[Parameter]
    composition: Expression  # The pipe composition expression
    return_type: TypeHint | None = None
    docstring: str | None = None  # Docstring extracted from preceding string literal
    location: Location | None = None


@dataclass
class StructDefinition:
    """Struct definition statement (e.g., struct Point: x: int, y: int)."""

    name: str
    fields: list["StructField"]
    docstring: str | None = None  # Docstring extracted from preceding string literal
    location: Location | None = None


@dataclass
class InterfaceDefinition:
    """Interface definition statement (e.g., interface IAgent: plan(problem: str) -> IWorkflow)."""

    name: str
    methods: list["InterfaceMethod"]
    embedded_interfaces: list[str] = field(default_factory=list)  # Names of embedded interfaces
    docstring: str | None = None  # Docstring extracted from preceding string literal
    location: Location | None = None


@dataclass
class TypedParameter:
    """A parameter with type information for interface methods."""

    name: str
    type_hint: TypeHint | None = None
    default_value: Expression | None = None
    location: Location | None = None


@dataclass
class InterfaceMethod:
    """A method signature in an interface definition."""

    name: str
    parameters: list["TypedParameter"]
    return_type: TypeHint | None = None
    comment: str | None = None  # Method description from inline comment
    location: Location | None = None


@dataclass
class ResourceDefinition:
    """Resource definition statement (e.g., resource MyRAG: sources: list[str])."""

    name: str
    fields: list["StructField"] = field(default_factory=list)
    methods: list["FunctionDefinition"] = field(default_factory=list)
    docstring: str | None = None
    location: Location | None = None


@dataclass
class WorkflowDefinition:
    """Workflow definition statement (e.g., workflow MyWorkflow: steps: list[str])."""

    name: str
    fields: list["StructField"] = field(default_factory=list)
    methods: list["FunctionDefinition"] = field(default_factory=list)
    docstring: str | None = None
    location: Location | None = None


@dataclass
class StructField:
    """A field in a struct definition."""

    name: str
    type_hint: TypeHint
    comment: str | None = None  # Field description from inline comment
    default_value: Expression | None = None
    location: Location | None = None


@dataclass
class ResourceField:
    """A field in a resource definition."""

    name: str
    type_hint: TypeHint
    comment: str | None = None  # Field description from inline comment
    default_value: Expression | None = None
    location: Location | None = None


@dataclass
class StructLiteral:
    """Struct instantiation expression (e.g., Point(x=10, y=20))."""

    struct_name: str
    arguments: list["StructArgument"]
    location: Location | None = None


@dataclass
class StructArgument:
    """A named argument in struct instantiation."""

    name: str
    value: Expression
    location: Location | None = None


@dataclass
class ImportStatement:
    """Import statement (e.g., import math)."""

    module: str
    alias: str | None = None
    location: Location | None = None


@dataclass
class ImportFromStatement:
    """From-import statement (e.g., from math import sqrt or from math import *)."""

    module: str
    names: list[tuple[str, str | None]]
    is_star_import: bool = False
    location: Location | None = None


@dataclass
class Decorator:
    """Decorator applied to a function (e.g., @poet(domain="building_management"))."""

    name: str  # Decorator name (e.g., "poet")
    args: list[Expression] = field(default_factory=list)  # Positional arguments
    kwargs: dict[str, Expression] = field(default_factory=dict)  # Keyword arguments
    location: Location | None = None


@dataclass
class BreakStatement:
    """Break statement."""

    location: Location | None = None


@dataclass
class ContinueStatement:
    """Continue statement."""

    location: Location | None = None


@dataclass
class PassStatement:
    """Pass statement."""

    location: Location | None = None


@dataclass
class ReturnStatement:
    """Return statement."""

    value: Expression | None = None
    location: Location | None = None


@dataclass
class RaiseStatement:
    """Raise statement."""

    value: Expression | None = None
    from_value: Expression | None = None
    location: Location | None = None


@dataclass
class AssertStatement:
    """Assert statement."""

    condition: Expression
    message: Expression | None = None
    location: Location | None = None


@dataclass
class ExportStatement:
    """AST node for export statements."""

    name: str

    def __str__(self) -> str:
        return f"export {self.name}"


# === Agent Definitions ===


@dataclass
class AgentDefinition:
    """Agent definition statement (e.g., agent SemiconductorInspector: process_type: str, tolerance_threshold: float)."""

    name: str
    fields: list["StructField"]
    methods: list["FunctionDefinition"] = field(default_factory=list)
    docstring: str | None = None
    location: Location | None = None


@dataclass
class SingletonAgentDefinition:
    """Singleton agent definition referencing a blueprint and optional overrides."""

    blueprint_name: str
    overrides: list["SingletonAgentField"]
    alias_name: str | None = None
    docstring: str | None = None
    location: Location | None = None


@dataclass
class BaseAgentSingletonDefinition:
    """Base agent singleton definition (e.g., agent John)."""

    alias_name: str
    location: Location | None = None


@dataclass
class SingletonAgentField:
    """An override assignment in a singleton agent definition block."""

    name: str
    value: Expression
    location: Location | None = None


# === Program Root ===
@dataclass
class Program:
    """The root node for a Dana program (list of statements)."""

    statements: list[Union[Assignment, FunctionCall, "ObjectFunctionCall"]]
    source_text: str = ""
    location: Location | None = None

    def __init__(self, statements, source_text: str = ""):
        self.statements = statements
        self.source_text = source_text
