use crate::llvm::build::Env;
use inkwell::values::{BasicValueEnum, PointerValue};
use roc_builtins::bitcode;
use roc_mono::layout::{InLayout, Layout, LayoutInterner, LayoutRepr, STLayoutInterner};

use super::bitcode::{call_str_bitcode_fn, BitcodeReturns};
use super::build::load_roc_value;

pub static CHAR_LAYOUT: InLayout = Layout::U8;

pub(crate) fn decode_from_utf8_result<'a, 'ctx>(
    env: &Env<'a, 'ctx, '_>,
    layout_interner: &mut STLayoutInterner<'a>,
    pointer: PointerValue<'ctx>,
) -> BasicValueEnum<'ctx> {
    let layout = LayoutRepr::Struct(env.arena.alloc([
        Layout::usize(env.target_info),
        Layout::STR,
        Layout::BOOL,
        Layout::U8,
    ]));
    // TODO: have load_roc_value use LayoutRepr
    let layout = layout_interner.insert_direct_no_semantic(layout);

    load_roc_value(
        env,
        layout_interner,
        layout,
        pointer,
        "load_decode_from_utf8_result",
    )
}

/// Dec.toStr : Dec -> Str

/// Str.equal : Str, Str -> Bool
pub(crate) fn str_equal<'ctx>(
    env: &Env<'_, 'ctx, '_>,
    value1: BasicValueEnum<'ctx>,
    value2: BasicValueEnum<'ctx>,
) -> BasicValueEnum<'ctx> {
    call_str_bitcode_fn(
        env,
        &[value1, value2],
        &[],
        BitcodeReturns::Basic,
        bitcode::STR_EQUAL,
    )
}

// Gets a pointer to just after the refcount for a list or seamless slice.
// The value is just after the refcount so that normal lists and seamless slices can share code paths easily.
pub(crate) fn str_refcount_ptr<'ctx>(
    env: &Env<'_, 'ctx, '_>,
    value: BasicValueEnum<'ctx>,
) -> PointerValue<'ctx> {
    call_str_bitcode_fn(
        env,
        &[value],
        &[],
        BitcodeReturns::Basic,
        bitcode::STR_REFCOUNT_PTR,
    )
    .into_pointer_value()
}