const std = @import("std");
const DiagnosticTag = @import("Diagnostics.zig").Tag;
const char_info = @import("char_info.zig");

pub const Compiler = enum {
    clang,
    gcc,
    msvc,
};

/// The floating-point evaluation method for intermediate results within a single expression
pub const FPEvalMethod = enum(i8) {
    /// The evaluation method cannot be determined or is inconsistent for this target.
    indeterminate = -1,
    /// Use the type declared in the source
    source = 0,
    /// Use double as the floating-point evaluation method for all float expressions narrower than double.
    double = 1,
    /// Use long double as the floating-point evaluation method for all float expressions narrower than long double.
    extended = 2,
};

pub const Standard = enum {
    /// ISO C 1990
    c89,
    /// ISO C 1990 with amendment 1
    iso9899,
    /// ISO C 1990 with GNU extensions
    gnu89,
    /// ISO C 1999
    c99,
    /// ISO C 1999 with GNU extensions
    gnu99,
    /// ISO C 2011
    c11,
    /// ISO C 2011 with GNU extensions
    gnu11,
    /// ISO C 2017
    c17,
    /// Default value if nothing specified; adds the GNU keywords to
    /// C17 but does not suppress warnings about using GNU extensions
    default,
    /// ISO C 2017 with GNU extensions
    gnu17,
    /// Working Draft for ISO C23
    c23,
    /// Working Draft for ISO C23 with GNU extensions
    gnu23,

    const NameMap = std.StaticStringMap(Standard).initComptime(.{
        .{ "c89", .c89 },                .{ "c90", .c89 },          .{ "iso9899:1990", .c89 },
        .{ "iso9899:199409", .iso9899 }, .{ "gnu89", .gnu89 },      .{ "gnu90", .gnu89 },
        .{ "c99", .c99 },                .{ "iso9899:1999", .c99 }, .{ "c9x", .c99 },
        .{ "iso9899:199x", .c99 },       .{ "gnu99", .gnu99 },      .{ "gnu9x", .gnu99 },
        .{ "c11", .c11 },                .{ "iso9899:2011", .c11 }, .{ "c1x", .c11 },
        .{ "iso9899:201x", .c11 },       .{ "gnu11", .gnu11 },      .{ "c17", .c17 },
        .{ "iso9899:2017", .c17 },       .{ "c18", .c17 },          .{ "iso9899:2018", .c17 },
        .{ "gnu17", .gnu17 },            .{ "gnu18", .gnu17 },      .{ "c23", .c23 },
        .{ "gnu23", .gnu23 },            .{ "c2x", .c23 },          .{ "gnu2x", .gnu23 },
    });

    pub fn atLeast(self: Standard, other: Standard) bool {
        return @intFromEnum(self) >= @intFromEnum(other);
    }

    pub fn isGNU(standard: Standard) bool {
        return switch (standard) {
            .gnu89, .gnu99, .gnu11, .default, .gnu17, .gnu23 => true,
            else => false,
        };
    }

    pub fn isExplicitGNU(standard: Standard) bool {
        return standard.isGNU() and standard != .default;
    }

    /// Value reported by __STDC_VERSION__ macro
    pub fn StdCVersionMacro(standard: Standard) ?[]const u8 {
        return switch (standard) {
            .c89, .gnu89 => null,
            .iso9899 => "199409L",
            .c99, .gnu99 => "199901L",
            .c11, .gnu11 => "201112L",
            .default, .c17, .gnu17 => "201710L",
            .c23, .gnu23 => "202311L",
        };
    }

    pub fn codepointAllowedInIdentifier(standard: Standard, codepoint: u21, is_start: bool) bool {
        if (is_start) {
            return if (standard.atLeast(.c23))
                char_info.isXidStart(codepoint)
            else if (standard.atLeast(.c11))
                char_info.isC11IdChar(codepoint) and !char_info.isC11DisallowedInitialIdChar(codepoint)
            else
                char_info.isC99IdChar(codepoint) and !char_info.isC99DisallowedInitialIDChar(codepoint);
        } else {
            return if (standard.atLeast(.c23))
                char_info.isXidContinue(codepoint)
            else if (standard.atLeast(.c11))
                char_info.isC11IdChar(codepoint)
            else
                char_info.isC99IdChar(codepoint);
        }
    }
};

const LangOpts = @This();

emulate: Compiler = .clang,
standard: Standard = .default,
/// -fshort-enums option, makes enums only take up as much space as they need to hold all the values.
short_enums: bool = false,
dollars_in_identifiers: bool = true,
declspec_attrs: bool = false,
ms_extensions: bool = false,
/// true or false if digraph support explicitly enabled/disabled with -fdigraphs/-fno-digraphs
digraphs: ?bool = null,
/// If set, use the native half type instead of promoting to float
use_native_half_type: bool = false,
/// If set, function arguments and return values may be of type __fp16 even if there is no standard ABI for it
allow_half_args_and_returns: bool = false,
/// null indicates that the user did not select a value, use target to determine default
fp_eval_method: ?FPEvalMethod = null,
/// If set, use specified signedness for `char` instead of the target's default char signedness
char_signedness_override: ?std.builtin.Signedness = null,
/// If set, override the default availability of char8_t (by default, enabled in C23 and later; disabled otherwise)
has_char8_t_override: ?bool = null,

/// Whether to allow GNU-style inline assembly
gnu_asm: bool = true,

/// Preserve comments when preprocessing
preserve_comments: bool = false,
/// Preserve comments in macros when preprocessing
preserve_comments_in_macros: bool = false,

/// Used ONLY for generating __GNUC__ and related macros. Does not control the presence/absence of any features
/// Encoded as major * 10,000 + minor * 100 + patch
/// e.g. 4.2.1 == 40201
gnuc_version: u32 = 0,

pub fn setStandard(self: *LangOpts, name: []const u8) error{InvalidStandard}!void {
    self.standard = Standard.NameMap.get(name) orelse return error.InvalidStandard;
}

pub fn enableMSExtensions(self: *LangOpts) void {
    self.declspec_attrs = true;
    self.ms_extensions = true;
}

pub fn disableMSExtensions(self: *LangOpts) void {
    self.declspec_attrs = false;
    self.ms_extensions = true;
}

pub fn hasChar8_T(self: *const LangOpts) bool {
    return self.has_char8_t_override orelse self.standard.atLeast(.c23);
}

pub fn hasDigraphs(self: *const LangOpts) bool {
    return self.digraphs orelse self.standard.atLeast(.gnu89);
}

pub fn setEmulatedCompiler(self: *LangOpts, compiler: Compiler) void {
    self.emulate = compiler;
    if (compiler == .msvc) self.enableMSExtensions();
}

pub fn setFpEvalMethod(self: *LangOpts, fp_eval_method: FPEvalMethod) void {
    self.fp_eval_method = fp_eval_method;
}

pub fn setCharSignedness(self: *LangOpts, signedness: std.builtin.Signedness) void {
    self.char_signedness_override = signedness;
}