import os
import strings

const parallel_tests_dir = os.dir(@FILE)
const parallel_v3_dir = os.dir(parallel_tests_dir)
const parallel_vlib_dir = os.dir(parallel_v3_dir)
const parallel_v3_src = os.join_path(parallel_v3_dir, 'v3.v')

// build_parallel_v3 builds parallel v3 data for v3 tests.
fn build_parallel_v3() string {
    vexe := @VEXE
    v3_bin := os.join_path(os.temp_dir(), 'v3_parallel_cgen_test')
    os.rm(v3_bin) or {}
    build :=
        os.execute('${vexe} -d parallel -gc none -path "${parallel_vlib_dir}|@vlib|@vmodules" -o ${v3_bin} ${parallel_v3_src}')
    assert build.exit_code == 0, build.output
    return v3_bin
}

fn build_parallel_prod_v3() string {
    vexe := @VEXE
    v3_bin := os.join_path(os.temp_dir(), 'v3_parallel_prod_cgen_test_${os.getpid()}')
    os.rm(v3_bin) or {}
    build :=
        os.execute('${vexe} -d parallel -gc none -prod -path "${parallel_vlib_dir}|@vlib|@vmodules" -o ${v3_bin} ${parallel_v3_src}')
    assert build.exit_code == 0, build.output
    return v3_bin
}

// write_parallel_module_init_project writes parallel module init project output for v3 tests.
fn write_parallel_module_init_project(name string) string {
    project_dir := os.join_path(os.temp_dir(), 'v3_${name}')
    os.rmdir_all(project_dir) or {}
    os.mkdir_all(os.join_path(project_dir, 'moda')) or { panic(err) }

    mut main_src := strings.new_builder(64_000)
    main_src.writeln('module main')
    main_src.writeln('')
    main_src.writeln('import moda')
    main_src.writeln('')
    for i in 0 .. 1050 {
        main_src.writeln('fn helper_${i}() int {')
        main_src.writeln('\treturn ${i}')
        main_src.writeln('}')
        main_src.writeln('')
    }
    main_src.writeln('fn main() {')
    main_src.writeln('\tmut total := 0')
    for i in 0 .. 1050 {
        main_src.writeln('\ttotal += helper_${i}()')
    }
    main_src.writeln('\tprintln(int_str(total + moda.value()))')
    main_src.writeln('}')
    os.write_file(os.join_path(project_dir, 'main.v'), main_src.str()) or { panic(err) }

    os.write_file(os.join_path(project_dir, 'moda', 'moda.v'), 'module moda

__global x int

fn init() {
    x = 7
}

pub fn value() int {
    return x
}
') or {
        panic(err)
    }
    return os.join_path(project_dir, 'main.v')
}

// test_parallel_cgen_main_emits_module_init_call validates this v3 regression case.
fn test_parallel_cgen_main_emits_module_init_call() {
    v3_bin := build_parallel_v3()
    main_path := write_parallel_module_init_project('parallel_module_init')
    c_out := os.join_path(os.temp_dir(), 'v3_parallel_module_init.c')
    compile := os.execute('VJOBS=2 ${v3_bin} ${main_path} -o ${c_out}')
    assert compile.exit_code == 0, compile.output
    assert compile.output.contains('cgen'), compile.output
    c_code := os.read_file(c_out) or { panic(err) }
    assert c_code.all_after('int main').contains('_vinit();')
}

fn write_parallel_gettid_project(name string) string {
    project_dir := os.join_path(os.temp_dir(), 'v3_${name}')
    os.rmdir_all(project_dir) or {}
    os.mkdir_all(project_dir) or { panic(err) }

    mut main_src := strings.new_builder(96_000)
    main_src.writeln('module main')
    main_src.writeln('')
    main_src.writeln('fn C.gettid() int')
    main_src.writeln('')
    for i in 0 .. 1050 {
        main_src.writeln('fn helper_${i}() int {')
        main_src.writeln('\treturn ${i}')
        main_src.writeln('}')
        main_src.writeln('')
    }
    main_src.writeln('fn worker_gettid_value() int {')
    main_src.writeln('\treturn C.gettid()')
    main_src.writeln('}')
    main_src.writeln('')
    main_src.writeln('fn main() {')
    main_src.writeln('\tmut total := 0')
    for i in 0 .. 1050 {
        main_src.writeln('\ttotal += helper_${i}()')
    }
    main_src.writeln('\tprintln(int_str(total + worker_gettid_value()))')
    main_src.writeln('}')
    os.write_file(os.join_path(project_dir, 'main.v'), main_src.str()) or { panic(err) }
    return os.join_path(project_dir, 'main.v')
}

fn test_parallel_cgen_merges_worker_gettid_compat() {
    v3_bin := build_parallel_v3()
    main_path := write_parallel_gettid_project('parallel_gettid_compat')
    c_out := os.join_path(os.temp_dir(), 'v3_parallel_gettid_compat.c')
    compile := os.execute('VJOBS=2 ${v3_bin} ${main_path} -o ${c_out}')
    assert compile.exit_code == 0, compile.output
    assert compile.output.contains('cgen'), compile.output
    c_code := os.read_file(c_out) or { panic(err) }
    assert c_code.contains('static inline u32 v3_gettid(void)'), c_code
    assert c_code.contains('return v3_gettid();'), c_code
}

fn write_parallel_user_main_test_project(name string) string {
    project_dir := os.join_path(os.temp_dir(), 'v3_${name}')
    os.rmdir_all(project_dir) or {}
    os.mkdir_all(project_dir) or { panic(err) }

    mut main_src := strings.new_builder(96_000)
    main_src.writeln('module main')
    main_src.writeln('')
    for i in 0 .. 1050 {
        main_src.writeln('fn helper_${i}() int {')
        main_src.writeln('\treturn ${i}')
        main_src.writeln('}')
        main_src.writeln('')
    }
    main_src.writeln('fn main() {')
    main_src.writeln("\tprintln('user-main')")
    main_src.writeln('}')
    main_src.writeln('')
    main_src.writeln('fn test_call_user_main() {')
    main_src.writeln('\tmut total := 0')
    for i in 0 .. 1050 {
        main_src.writeln('\ttotal += helper_${i}()')
    }
    main_src.writeln('\tassert total == 550725')
    main_src.writeln('\tmain()')
    main_src.writeln('}')
    os.write_file(os.join_path(project_dir, 'main_test.v'), main_src.str()) or { panic(err) }
    return os.join_path(project_dir, 'main_test.v')
}

fn test_parallel_cgen_worker_keeps_test_user_main_renamed() {
    v3_bin := build_parallel_v3()
    main_path := write_parallel_user_main_test_project('parallel_user_main_test_file')
    bin_out := os.join_path(os.temp_dir(), 'v3_parallel_user_main_test_file_out')
    compile := os.execute('VJOBS=2 ${v3_bin} ${main_path} -b c -o ${bin_out}')
    assert compile.exit_code == 0, compile.output
    assert compile.output.contains('cgen'), compile.output
    run := os.execute(bin_out)
    assert run.exit_code == 0, run.output
    assert run.output.trim_space() == 'user-main'
    c_code := os.read_file(bin_out + '.c') or { panic(err) }
    assert c_code.count('int main(') == 1, c_code
    assert c_code.contains('main__user_main'), c_code
    assert c_code.contains('main__user_main();'), c_code
}

fn write_parallel_generic_struct_method_project(name string) string {
    project_dir := os.join_path(os.temp_dir(), 'v3_${name}')
    os.rmdir_all(project_dir) or {}
    os.mkdir_all(project_dir) or { panic(err) }

    mut main_src := strings.new_builder(96_000)
    main_src.writeln('module main')
    main_src.writeln('')
    main_src.writeln('struct Box[T] {')
    main_src.writeln('    value T')
    main_src.writeln('}')
    main_src.writeln('')
    main_src.writeln('fn (b Box[T]) accept(x ?T) T {')
    main_src.writeln('    value := x or {')
    main_src.writeln('        return b.value')
    main_src.writeln('    }')
    main_src.writeln('    return value')
    main_src.writeln('}')
    main_src.writeln('')
    main_src.writeln('fn use_box_accept() int {')
    main_src.writeln('    b := Box[int]{')
    main_src.writeln('        value: 5')
    main_src.writeln('    }')
    main_src.writeln('    return b.accept(7) + b.accept(8)')
    main_src.writeln('}')
    main_src.writeln('')
    for i in 0 .. 1050 {
        main_src.writeln('fn helper_${i}() int {')
        main_src.writeln('\treturn ${i}')
        main_src.writeln('}')
        main_src.writeln('')
    }
    main_src.writeln('fn main() {')
    main_src.writeln('\tmut total := use_box_accept()')
    for i in 0 .. 1050 {
        main_src.writeln('\ttotal += helper_${i}()')
    }
    main_src.writeln('\tprintln(int_str(total))')
    main_src.writeln('}')
    os.write_file(os.join_path(project_dir, 'main.v'), main_src.str()) or { panic(err) }
    return os.join_path(project_dir, 'main.v')
}

fn test_parallel_cgen_worker_resolves_generic_struct_method_signature() {
    v3_bin := build_parallel_v3()
    main_path := write_parallel_generic_struct_method_project('parallel_generic_struct_method')
    bin_out := os.join_path(os.temp_dir(), 'v3_parallel_generic_struct_method_out')
    compile := os.execute('VJOBS=2 ${v3_bin} ${main_path} -b c -o ${bin_out}')
    assert compile.exit_code == 0, compile.output
    assert compile.output.contains('cgen (parallel)'), compile.output
    run := os.execute(bin_out)
    assert run.exit_code == 0, run.output
    assert run.output.trim_space() == '550740'
    c_code := os.read_file(bin_out + '.c') or { panic(err) }
    assert c_code.contains('Box_int__accept'), c_code
    assert c_code.contains('Optional_int x'), c_code
    assert !c_code.contains('?T'), c_code
}

fn write_parallel_top_level_no_main_project(name string) string {
    project_dir := os.join_path(os.temp_dir(), 'v3_${name}')
    os.rmdir_all(project_dir) or {}
    os.mkdir_all(project_dir) or { panic(err) }

    mut main_src := strings.new_builder(48_000)
    main_src.writeln('module main')
    main_src.writeln('')
    for i in 0 .. 320 {
        main_src.writeln('fn helper_${i}() int {')
        main_src.writeln('\treturn ${i}')
        main_src.writeln('}')
        main_src.writeln('')
    }
    main_src.writeln('mut values := map[string]int{}')
    main_src.writeln("mut total := values['missing'] or {")
    main_src.writeln('\t7')
    main_src.writeln('}')
    for i in 0 .. 320 {
        main_src.writeln('total += helper_${i}()')
    }
    main_src.writeln('println(int_str(total))')
    os.write_file(os.join_path(project_dir, 'main.v'), main_src.str()) or { panic(err) }
    return os.join_path(project_dir, 'main.v')
}

fn test_parallel_transform_lowers_top_level_stmts_without_main_once() {
    v3_bin := build_parallel_v3()
    main_path := write_parallel_top_level_no_main_project('parallel_top_level_no_main')
    bin_out := os.join_path(os.temp_dir(), 'v3_parallel_top_level_no_main_out')
    compile := os.execute('VJOBS=2 ${v3_bin} --parallel-transform ${main_path} -b c -o ${bin_out}')
    assert compile.exit_code == 0, compile.output
    assert compile.output.contains('transform (parallel)'), compile.output
    assert compile.output.contains('cgen'), compile.output
    run := os.execute(bin_out)
    assert run.exit_code == 0, run.output
    assert run.output.trim_space() == '51047'
    c_code := os.read_file(bin_out + '.c') or { panic(err) }
    assert c_code.all_after('int main').count('map__get_check') == 1, c_code
}

fn test_parallel_transform_selfhost_builds_v3() {
    v3_bin := build_parallel_prod_v3()
    bin_out := os.join_path(os.temp_dir(), 'v3_parallel_selfhost_out_${os.getpid()}')
    os.rm(bin_out) or {}
    os.rm(bin_out + '.c') or {}
    compile :=
        os.execute('VJOBS=2 ${v3_bin} -building-v -parallel-transform -parallel -o ${bin_out} ${parallel_v3_src}')
    assert compile.exit_code == 0, compile.output
    assert compile.output.contains('transform (parallel)'), compile.output
    assert compile.output.contains('cgen (parallel)'), compile.output
    assert os.exists(bin_out), compile.output
    c_code := os.read_file(bin_out + '.c') or { panic(err) }
    assert c_code.contains('Array_u8__bytestr'), c_code
    assert c_code.contains('Array_u8__hex'), c_code
}