import os
import strings

const const_cb_vexe = @VEXE
const const_cb_tests_dir = os.dir(@FILE)
const const_cb_v3_dir = os.dir(const_cb_tests_dir)
const const_cb_vlib_dir = os.dir(const_cb_v3_dir)
const const_cb_v3_src = os.join_path(const_cb_v3_dir, 'v3.v')

fn const_cb_build_v3() string {
    return const_cb_build_v3_with_flags('serial', '')
}

fn const_cb_build_v3_parallel() string {
    return const_cb_build_v3_with_flags('parallel', '-d parallel')
}

fn const_cb_build_v3_with_flags(name string, flags string) string {
    v3_bin := os.join_path(os.temp_dir(), 'v3_const_callback_test_${name}_${os.getpid()}')
    os.rm(v3_bin) or {}
    build :=
        os.execute('${const_cb_vexe} ${flags} -gc none -path "${const_cb_vlib_dir}|@vlib|@vmodules" -o ${v3_bin} ${const_cb_v3_src}')
    assert build.exit_code == 0, build.output
    return v3_bin
}

fn const_cb_write_project(source string) string {
    root := os.join_path(os.temp_dir(), 'v3_const_callback_${os.getpid()}')
    os.rmdir_all(root) or {}
    os.mkdir_all(root) or { panic(err) }
    header := '#ifndef V3_CONST_CALLBACK_NATIVE_H
#define V3_CONST_CALLBACK_NATIVE_H
typedef struct native_event {
    int value;
} native_event;
typedef struct native_desc {
    void (*cb)(const struct native_event*, void*);
    void (*plain)(struct native_event*, void*);
    void* user_data;
} native_desc;
typedef struct alias_desc {
    void (*cb)(const struct native_event*, void*);
    void* user_data;
} alias_desc;
typedef struct late_alias_desc {
    void (*cb)(const struct native_event*, void*);
    void* user_data;
} late_alias_desc;
#endif
'
    os.write_file(os.join_path(root, 'native_callback.h'), header) or { panic(err) }
    path := os.join_path(root, 'main.v')
    os.write_file(path, source) or { panic(err) }
    return path
}

fn test_c_callback_const_qualifier_codegen() {
    v3_bin := const_cb_build_v3()
    src := const_cb_write_project('module main

#include "@DIR/native_callback.h"

@[typedef]
struct C.native_event {
    value int
}

type Event = C.native_event
type ConstNativeCb = fn (const_event &Event, user_data voidptr)

@[typedef]
struct C.native_desc {
mut:
    cb fn (const_event &C.native_event, voidptr) = unsafe { nil }
    plain fn (&C.native_event, voidptr) = unsafe { nil }
    user_data voidptr
}

@[typedef]
struct C.alias_desc {
mut:
    cb ConstNativeCb = unsafe { nil }
    user_data voidptr
}

struct App {
mut:
    hits int
}

fn erased_event(e voidptr, data voidptr) {
    event := unsafe { &C.native_event(e) }
    mut app := unsafe { &App(data) }
    app.hits += event.value
}

fn plain_event(e &C.native_event, data voidptr) {
    mut app := unsafe { &App(data) }
    app.hits += e.value * 10
}

fn concrete_event(e &C.native_event, data voidptr) {
    mut app := unsafe { &App(data) }
    app.hits += e.value * 100
}

fn main() {
    mut app := App{}
    mut desc := C.native_desc{
        cb: erased_event
        plain: plain_event
        user_data: voidptr(&app)
    }
    event := C.native_event{value: 3}
    desc.cb = erased_event
    desc.cb(&event, desc.user_data)
    desc.plain(&event, desc.user_data)
    mut concrete := C.native_desc{
        user_data: voidptr(&app)
    }
    concrete.cb = concrete_event
    concrete.cb(&event, concrete.user_data)
    mut alias_desc := C.alias_desc{
        user_data: voidptr(&app)
    }
    alias_desc.cb = concrete_event
    alias_desc.cb(&event, alias_desc.user_data)
    println(int_str(app.hits))
}
')
    out := os.join_path(os.temp_dir(), 'v3_const_callback_out_${os.getpid()}')
    compile := os.execute('${v3_bin} ${src} -b c -o ${out}')
    assert compile.exit_code == 0, compile.output
    run := os.execute(out)
    assert run.exit_code == 0, run.output
    assert run.output.trim_space() == '633'
    generated := os.read_file(out + '.c') or { panic(err) }
    assert generated.contains('typedef void (*'), generated
    assert generated.contains('(const struct native_event*, void*)'), generated
    assert generated.contains('(struct native_event*, void*)'), generated
    assert generated.contains('erased_event_callback_adapter_'), generated
    assert generated.contains('concrete_event_callback_adapter_'), generated
    assert generated.contains('const struct native_event* arg0, void* arg1'), generated
    assert generated.contains('erased_event((void*)arg0, arg1);'), generated
    assert generated.contains('concrete_event((struct native_event*)arg0, arg1);'), generated
    assert generated.contains('.cb = erased_event_callback_adapter_'), generated
    assert generated.contains('desc.cb = erased_event_callback_adapter_'), generated
    assert generated.contains('concrete.cb = concrete_event_callback_adapter_'), generated
    assert generated.contains('alias_desc.cb = concrete_event_callback_adapter_'), generated
    assert generated.contains('.plain = plain_event'), generated
    assert !generated.contains('.cb = (_fn_ptr'), generated
    assert !generated.contains('desc.cb = (_fn_ptr'), generated
    assert !generated.contains('concrete.cb = concrete_event;'), generated
    assert !generated.contains('alias_desc.cb = concrete_event;'), generated
    assert !generated.contains('.plain = plain_event_callback_adapter_'), generated
}

fn test_generic_heap_positional_c_callback_codegen() {
    v3_bin := const_cb_build_v3()
    src := const_cb_write_project('module main

#include "@DIR/native_callback.h"

@[typedef]
struct C.native_event {
    value int
}

@[typedef]
struct C.native_desc {
mut:
    cb fn (const_event &C.native_event, voidptr) = unsafe { nil }
    plain fn (&C.native_event, voidptr) = unsafe { nil }
    user_data voidptr
}

struct App {
mut:
    hits int
}

fn concrete_event(e &C.native_event, data voidptr) {
    mut app := unsafe { &App(data) }
    app.hits += e.value
}

fn plain_event(e &C.native_event, data voidptr) {
    mut app := unsafe { &App(data) }
    app.hits += e.value * 10
}

fn make_desc[T](data T) &C.native_desc {
    return &C.native_desc{concrete_event, plain_event, voidptr(data)}
}

fn main() {
    mut app := App{}
    event := C.native_event{value: 5}
    desc := make_desc(&app)
    desc.cb(&event, desc.user_data)
    desc.plain(&event, desc.user_data)
    println(int_str(app.hits))
}
')
    out := os.join_path(os.temp_dir(), 'v3_const_callback_heap_positional_out_${os.getpid()}')
    compile := os.execute('${v3_bin} ${src} -b c -o ${out}')
    assert compile.exit_code == 0, compile.output
    run := os.execute(out)
    assert run.exit_code == 0, run.output
    assert run.output.trim_space() == '55'
    generated := os.read_file(out + '.c') or { panic(err) }
    assert generated.contains('concrete_event_callback_adapter_'), generated
    assert generated.contains('.cb = concrete_event_callback_adapter_'), generated
    assert !generated.contains('.cb = concrete_event,'), generated
}

fn test_c_callback_c_alias_declared_after_field_codegen() {
    v3_bin := const_cb_build_v3()
    src := const_cb_write_project('module main

#include "@DIR/native_callback.h"

@[typedef]
struct C.late_alias_desc {
mut:
    cb fn (&Event, voidptr) = unsafe { nil }
    user_data voidptr
}

@[typedef]
struct C.native_event {
    value int
}

type Event = C.native_event

struct App {
mut:
    hits int
}

fn late_alias_event(e &C.native_event, data voidptr) {
    mut app := unsafe { &App(data) }
    app.hits += e.value
}

fn main() {
    mut app := App{}
    event := C.native_event{value: 11}
    mut desc := C.late_alias_desc{
        cb: late_alias_event
        user_data: voidptr(&app)
    }
    desc.cb(&event, desc.user_data)
    desc.cb = late_alias_event
    desc.cb(&event, desc.user_data)
    println(int_str(app.hits))
}
')
    out := os.join_path(os.temp_dir(), 'v3_const_callback_late_alias_out_${os.getpid()}')
    compile := os.execute('${v3_bin} ${src} -b c -o ${out}')
    assert compile.exit_code == 0, compile.output
    run := os.execute(out)
    assert run.exit_code == 0, run.output
    assert run.output.trim_space() == '22'
    generated := os.read_file(out + '.c') or { panic(err) }
    assert generated.contains('(const struct native_event*, void*)'), generated
    assert generated.contains('late_alias_event_callback_adapter_'), generated
    assert generated.contains('const struct native_event* arg0, void* arg1'), generated
    assert generated.contains('late_alias_event((struct native_event*)arg0, arg1);'), generated
    assert generated.contains('.cb = late_alias_event_callback_adapter_'), generated
    assert generated.contains('desc.cb = late_alias_event_callback_adapter_'), generated
    assert !generated.contains('main__Event*'), generated
    assert !generated.contains('.cb = late_alias_event,'), generated
    assert !generated.contains('desc.cb = late_alias_event;'), generated
}

fn test_c_callback_const_qualifier_parallel_worker_codegen() {
    v3_bin := const_cb_build_v3_parallel()
    mut src := strings.new_builder(96 * 1024)
    src.write_string('module main

#include "@DIR/native_callback.h"

@[typedef]
struct C.native_event {
    value int
}

type Event = C.native_event
type ConstNativeCb = fn (const_event &Event, user_data voidptr)

@[typedef]
struct C.alias_desc {
mut:
    cb ConstNativeCb = unsafe { nil }
    user_data voidptr
}

struct App {
mut:
    hits int
}

fn concrete_event(e &C.native_event, data voidptr) {
    mut app := unsafe { &App(data) }
    app.hits += e.value
}

')
    for i in 0 .. 1100 {
        src.write_string('fn filler_${i}() int { return ${i} }\n')
    }
    src.write_string('
fn run_parallel(mut app App) {
    mut desc := C.alias_desc{
        user_data: voidptr(app)
    }
    desc.cb = concrete_event
    event := C.native_event{value: 7}
    desc.cb(&event, desc.user_data)
}

fn main() {
    mut app := App{}
    run_parallel(mut app)
    println(int_str(app.hits))
}
')
    path := const_cb_write_project(src.str())
    out := os.join_path(os.temp_dir(), 'v3_const_callback_parallel_out_${os.getpid()}')
    compile := os.execute('VJOBS=2 ${v3_bin} ${path} -b c -o ${out}')
    assert compile.exit_code == 0, compile.output
    run := os.execute(out)
    assert run.exit_code == 0, run.output
    assert run.output.trim_space() == '7'
    generated := os.read_file(out + '.c') or { panic(err) }
    assert generated.contains('concrete_event_callback_adapter_'), generated
    assert generated.contains('const struct native_event* arg0, void* arg1'), generated
    assert generated.contains('concrete_event((struct native_event*)arg0, arg1);'), generated
    assert generated.contains('desc.cb = concrete_event_callback_adapter_'), generated
    assert !generated.contains('const gg__Event'), generated
    assert !generated.contains('desc.cb = concrete_event;'), generated
}