//! CSS properties related to dimensions and sizing.

//!

//! Key types: [`LayoutWidth`] / [`LayoutHeight`] (support `auto`, pixel values,

//! `min-content`, `max-content`, `fit-content()`, and `calc()` expressions),

//! [`LayoutMinWidth`], [`LayoutMinHeight`], [`LayoutMaxWidth`], [`LayoutMaxHeight`]

//! (simple pixel-value constraints), and [`LayoutBoxSizing`].

//!

//! `calc()` expressions use a flat stack-machine representation via [`CalcAstItem`]

//! — see its documentation for the encoding scheme. The layout solver in

//! `layout/src/solver3/calc.rs` evaluates these at resolve time.

use alloc::{

    string::{String, ToString},

    vec::Vec,

};

use crate::{

    impl_option, impl_option_inner, impl_vec, impl_vec_clone, impl_vec_debug, impl_vec_eq,

    impl_vec_hash, impl_vec_mut, impl_vec_ord, impl_vec_partialeq, impl_vec_partialord,

    props::{

        basic::pixel::{CssPixelValueParseError, CssPixelValueParseErrorOwned, PixelValue},

        formatter::PrintAsCssValue,

        macros::PixelValueTaker,

    },

};

// -- Calc AST --

/// A single item in a `calc()` expression, stored as a flat stack-machine representation.

///

/// The expression `calc(33.333% - 10px)` is stored as:

/// ```text

/// [Value(33.333%), Sub, Value(10px)]

/// ```

///

/// For nested expressions like `calc(100% - (20px + 5%))`:

/// ```text

/// [Value(100%), Sub, BraceOpen, Value(20px), Add, Value(5%), BraceClose]

/// ```

///

/// **Resolution**: Walk left to right. When `BraceClose` is hit, resolve everything

/// back to the matching `BraceOpen`, replace that span with a single `Value`, and continue.

#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]

#[repr(C, u8)]

pub enum CalcAstItem {

    /// A literal value (e.g. `10px`, `33.333%`, `2em`)

    Value(PixelValue),

    /// `+` operator

    Add,

    /// `-` operator

    Sub,

    /// `*` operator

    Mul,

    /// `/` operator

    Div,

    /// `(` — opens a sub-expression

    BraceOpen,

    /// `)` — closes a sub-expression; triggers resolution of the inner span

    BraceClose,

}

/// C-compatible `Vec<CalcAstItem>` for FFI interop.

impl_vec!(

    CalcAstItem,

    CalcAstItemVec,

    CalcAstItemVecDestructor,

    CalcAstItemVecDestructorType,

    CalcAstItemVecSlice,

    OptionCalcAstItem

);

impl_vec_clone!(CalcAstItem, CalcAstItemVec, CalcAstItemVecDestructor);

impl_vec_debug!(CalcAstItem, CalcAstItemVec);

impl_vec_partialeq!(CalcAstItem, CalcAstItemVec);

impl_vec_eq!(CalcAstItem, CalcAstItemVec);

impl_vec_partialord!(CalcAstItem, CalcAstItemVec);

impl_vec_ord!(CalcAstItem, CalcAstItemVec);

impl_vec_hash!(CalcAstItem, CalcAstItemVec);

impl_vec_mut!(CalcAstItem, CalcAstItemVec);

impl_option!(

    CalcAstItem,

    OptionCalcAstItem,

    copy = false,

    [Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash]

);

/// Parse a calc() inner expression (the part between the parentheses) into

/// a flat `CalcAstItemVec` suitable for stack-machine evaluation.

///

/// Examples:

/// - `"100% - 20px"` → `[Value(100%), Sub, Value(20px)]`

/// - `"(100% - 20px) / 3"` → `[BraceOpen, Value(100%), Sub, Value(20px), BraceClose, Div, Value(3)]`

///

/// **Tokenisation rules**:

///  - Whitespace is skipped between tokens.

///  - `+`, `-`, `*`, `/` are operators (but `-` at the start of a number is

///    part of the number literal, e.g. `-10px`).

///  - `(` / `)` produce `BraceOpen` / `BraceClose`.

///  - Anything else is parsed as a `PixelValue` via `parse_pixel_value`.

#[cfg(feature = "parser")]

    use crate::props::basic::pixel::parse_pixel_value;

        // Skip whitespace

            b'-' => {

                // Decide: is this a subtraction operator or a negative number?

                // It's a negative number if:

                //   - it's the first token, OR

                //   - the previous token is an operator or BraceOpen

                        Some(CalcAstItem::Add)

                            | Some(CalcAstItem::Sub)

                            | Some(CalcAstItem::Mul)

                            | Some(CalcAstItem::Div)

                            | Some(CalcAstItem::BraceOpen)

                    );

                    // Parse as negative number value

            }

            _ => {

                // Must be a numeric value (e.g. 100%, 20px, 3, 1.5em)

            }

        }

    }

/// Find the end of a numeric value token in a calc() expression.

/// Returns the byte offset where the value ends.

#[cfg(feature = "parser")]

    // Optional leading sign

    // Digits and decimal point

    // Unit suffix (alphabetic characters like px, %, em, rem, vw, vh, etc.)

/// Format a `CalcAstItemVec` as a CSS `calc(...)` string.

// -- Type Definitions --

macro_rules! define_dimension_property {

    ($struct_name:ident, $default_fn:expr) => {

        #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]

        #[repr(C)]

        pub struct $struct_name {

            pub inner: PixelValue,

        }

        impl Default for $struct_name {

        }

        impl PixelValueTaker for $struct_name {

        }

        impl_pixel_value!($struct_name);

        impl PrintAsCssValue for $struct_name {

        }

    };

}

macro_rules! define_sizing_enum {

    ($name:ident) => {

        #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]

        #[repr(C, u8)]

        #[derive(Default)]

        pub enum $name {

            #[default]

            Auto,

            Px(PixelValue),

            MinContent,

            MaxContent,

            /// `fit-content(<length-percentage>)` = `min(max-content, max(min-content, <length-percentage>))`

            FitContent(PixelValue),

            /// `calc()` expression stored as a flat stack-machine AST

            Calc(CalcAstItemVec),

        }

        impl PixelValueTaker for $name {

        }

        impl PrintAsCssValue for $name {

                }

        }

        impl $name {

                }

        }

    };

}

define_sizing_enum!(LayoutWidth);

define_sizing_enum!(LayoutHeight);

/// CSS `min-width` property. Defaults to `0px`.

define_dimension_property!(LayoutMinWidth, || Self {

/// CSS `min-height` property. Defaults to `0px`.

define_dimension_property!(LayoutMinHeight, || Self {

/// CSS `max-width` property. Defaults to `f32::MAX` pixels (i.e. unconstrained).

///

/// NOTE: The layout solver must handle `f32::MAX` gracefully — adding

/// padding/margin to this sentinel would overflow to infinity.

define_dimension_property!(LayoutMaxWidth, || Self {

/// CSS `max-height` property. Defaults to `f32::MAX` pixels (i.e. unconstrained).

///

/// NOTE: The layout solver must handle `f32::MAX` gracefully — adding

/// padding/margin to this sentinel would overflow to infinity.

define_dimension_property!(LayoutMaxHeight, || Self {

/// Represents a `box-sizing` attribute

#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]

#[repr(C)]

#[derive(Default)]

pub enum LayoutBoxSizing {

    #[default]

    ContentBox,

    BorderBox,

}

impl PrintAsCssValue for LayoutBoxSizing {

        })

}

// -- Parser --

#[cfg(feature = "parser")]

pub mod parser {

    use alloc::string::ToString;

    use crate::corety::AzString;

    use super::*;

    use crate::props::basic::pixel::parse_pixel_value;

    macro_rules! define_pixel_dimension_parser {

        ($fn_name:ident, $struct_name:ident, $error_name:ident, $error_owned_name:ident) => {

            #[derive(Clone, PartialEq)]

            pub enum $error_name<'a> {

                PixelValue(CssPixelValueParseError<'a>),

            }

            impl_debug_as_display!($error_name<'a>);

            impl_display! { $error_name<'a>, {

                PixelValue(e) => format!("{}", e),

            }}

            impl_from! { CssPixelValueParseError<'a>, $error_name::PixelValue }

            #[derive(Debug, Clone, PartialEq)]

            #[repr(C, u8)]

            pub enum $error_owned_name {

                PixelValue(CssPixelValueParseErrorOwned),

            }

            impl<'a> $error_name<'a> {

                        }

                    }

            }

            impl $error_owned_name {

                    }

            }

        };

    }

    macro_rules! define_sizing_parser {

        ($fn_name:ident, $enum_name:ident, $error_name:ident, $error_owned_name:ident, $keyword_label:expr) => {

            #[derive(Clone, PartialEq)]

            pub enum $error_name<'a> {

                PixelValue(CssPixelValueParseError<'a>),

                InvalidKeyword(&'a str),

            }

            impl_debug_as_display!($error_name<'a>);

            impl_display! { $error_name<'a>, {

                PixelValue(e) => format!("{}", e),

                InvalidKeyword(k) => format!("Invalid {} keyword: \"{}\"", $keyword_label, k),

            }}

            impl_from! { CssPixelValueParseError<'a>, $error_name::PixelValue }

            #[derive(Debug, Clone, PartialEq)]

            #[repr(C, u8)]

            pub enum $error_owned_name {

                PixelValue(CssPixelValueParseErrorOwned),

                InvalidKeyword(AzString),

            }

            impl<'a> $error_name<'a> {

                        }

                        }

                    }

            }

            impl $error_owned_name {

                        }

                        }

                    }

            }

                                } else {

                                }

                    }

                    }

                }

        };

    }

    define_sizing_parser!(parse_layout_width, LayoutWidth, LayoutWidthParseError, LayoutWidthParseErrorOwned, "width");

    define_sizing_parser!(parse_layout_height, LayoutHeight, LayoutHeightParseError, LayoutHeightParseErrorOwned, "height");

    define_pixel_dimension_parser!(

        parse_layout_min_width,

        LayoutMinWidth,

        LayoutMinWidthParseError,

        LayoutMinWidthParseErrorOwned

    );

    define_pixel_dimension_parser!(

        parse_layout_min_height,

        LayoutMinHeight,

        LayoutMinHeightParseError,

        LayoutMinHeightParseErrorOwned

    );

    define_pixel_dimension_parser!(

        parse_layout_max_width,

        LayoutMaxWidth,

        LayoutMaxWidthParseError,

        LayoutMaxWidthParseErrorOwned

    );

    define_pixel_dimension_parser!(

        parse_layout_max_height,

        LayoutMaxHeight,

        LayoutMaxHeightParseError,

        LayoutMaxHeightParseErrorOwned

    );

    // -- Box Sizing Parser --

    #[derive(Clone, PartialEq)]

    pub enum LayoutBoxSizingParseError<'a> {

        InvalidValue(&'a str),

    }

    impl_debug_as_display!(LayoutBoxSizingParseError<'a>);

    impl_display! { LayoutBoxSizingParseError<'a>, {

        InvalidValue(v) => format!("Invalid box-sizing value: \"{}\"", v),

    }}

    #[derive(Debug, Clone, PartialEq)]

    #[repr(C, u8)]

    pub enum LayoutBoxSizingParseErrorOwned {

        InvalidValue(AzString),

    }

    impl<'a> LayoutBoxSizingParseError<'a> {

                }

            }

    }

    impl LayoutBoxSizingParseErrorOwned {

                }

            }

    }

        }

}

#[cfg(feature = "parser")]

pub use self::parser::*;

#[cfg(all(test, feature = "parser"))]

mod tests {

    use super::*;

    use crate::props::basic::pixel::PixelValue;

    #[test]

        );

        );

        );

        );

        );

            LayoutWidth::MinContent

        );

            LayoutWidth::MaxContent

        );

    #[test]

        // "auto" is now a valid value for height (CSS spec)

        // Liberal parsing accepts whitespace between number and unit

    #[test]

            LayoutBoxSizing::ContentBox

        );

            LayoutBoxSizing::BorderBox

        );

            LayoutBoxSizing::BorderBox

        );

    #[test]

}