#!/usr/local/bin/v

import os

const vexe = @VEXE
const tests_dir = os.dir(@FILE)
const v3_dir = os.dir(tests_dir)
const test_v = os.join_path(tests_dir, 'test_all_lang_features.v')
const test_out = os.join_path(tests_dir, 'test_all_lang_features.out')
const v3_src = os.join_path(v3_dir, 'v3.v')

fn run(cmd string) os.Result {
    println('> ${cmd}')
    return os.execute(cmd)
}

fn build_v3() string {
    v3_bin := os.join_path(os.temp_dir(), 'v3_test_runner')
    cmd := '${vexe} -o ${v3_bin} ${v3_src}'
    r := run(cmd)
    if r.exit_code != 0 {
        eprintln('FAIL: could not build v3')
        eprintln(r.output)
        exit(1)
    }
    return v3_bin
}

fn run_v3_c(v3_bin string) string {
    v3c_bin := '${os.temp_dir()}/v3c_test'
    r := run('${v3_bin} ${test_v} -b c -o ${v3c_bin}')
    if r.exit_code != 0 {
        eprintln('FAIL: v3 C backend compilation failed')
        eprintln(r.output)
        exit(1)
    }
    return run_stdout(v3c_bin)
}

fn run_stdout(cmd string) string {
    stdout_path := '${os.temp_dir()}/v3c_test_stdout'
    os.rm(stdout_path) or {}
    println('> ${cmd}')
    code := os.system('${cmd} > ${os.quoted_path(stdout_path)}')
    if code != 0 {
        eprintln('FAIL: command failed (exit ${code})')
        exit(code)
    }
    output := read_text_file(stdout_path)
    os.rm(stdout_path) or {}
    return output
}

fn read_text_file(path string) string {
    content := os.read_file(path) or {
        eprintln('FAIL: failed to read ${path}: ${err}')
        exit(1)
    }
    return content
}

fn assert_same_text(label string, actual string, expected string) {
    if actual == expected {
        return
    }
    actual_lines := actual.split_into_lines()
    expected_lines := expected.split_into_lines()
    min_lines := if actual_lines.len < expected_lines.len {
        actual_lines.len
    } else {
        expected_lines.len
    }
    for i in 0 .. min_lines {
        if actual_lines[i] != expected_lines[i] {
            eprintln('FAIL: ${label} differs at line ${i + 1}: expected `${expected_lines[i]}`, got `${actual_lines[i]}`')
            exit(1)
        }
    }
    eprintln('FAIL: ${label} line count differs: expected ${expected_lines.len}, got ${actual_lines.len}')
    exit(1)
}

// Build v3
v3_bin := build_v3()
println('built v3: ${v3_bin}')

// Run V3 backends
v3c_out := run_v3_c(v3_bin)
expected_out := read_text_file(test_out)
assert_same_text('v3 C fixture output', v3c_out, expected_out)
println('v3 C:     OK')

println('=== V3 C OK (${v3c_out.split_into_lines().len} lines) ===')