const std = @import("std");

const value = @import("../value.zig");
const gc = @import("../gc.zig");

const ptr = @import("ptr.zig");
const seq = @import("seq.zig");

const Hval = gc.Hval;

const Value = value.Value;

// Zig API

pub fn check(v: Value) bool {
    return ptr.checkZispTag(v, .seq);
}

pub fn assert(v: Value) void {
    if (!check(v)) {
        v.dump();
        @panic("not istr");
    }
}

pub fn intern(str: []const u8, quoted: bool) Value {
    if (str.len > value.fixnum.max) {
        @panic("String length out of fixnum range.");
    }
    const header: seq.Header = .{
        .type = .string,
        .info = .{ .string = .{
            .enc = .utf8,
            .quoted = quoted,
            .interned = true,
        } },
        .size = @intCast(str.len),
    };
    const header_ptr = gc.intern(header, str);
    return ptr.pack(@ptrCast(header_ptr), .seq);
}

pub fn getHeader(v: Value) *seq.Header {
    assert(v);
    const header_ptr, _ = ptr.unpack(v);
    return gc.istrHeader(header_ptr);
}

pub fn getHeaderFromPtr(p: *Hval) *seq.Header {
    return gc.istrHeader(p);
}

// Zisp API

pub fn pred(v: Value) Value {
    return value.boole.pack(check(v));
}

pub fn len(v: Value) Value {
    const l = getHeader(v).size;
    if (l > value.fixnum.max) {
        @panic("string length out of range");
    }
    return value.fixnum.pack(@intCast(l));
}