/*!
 * Unit tests for LoopForm v2 exit PHI generation
 *
 * Tests the build_exit_phis() implementation in loopform_builder.rs
 * Focus: predecessor tracking and PHI input generation for break statements
 */

use crate::parser::NyashParser;
use crate::mir::{MirCompiler, MirVerifier};

#[test]
fn test_loopform_exit_phi_single_break() {
    // Enable LoopForm PHI v2 and MIR verification
    std::env::set_var("NYASH_LOOPFORM_PHI_V2", "1");
    std::env::set_var("NYASH_VM_VERIFY_MIR", "1");
    std::env::set_var("NYASH_LOOPFORM_DEBUG", "1");
    std::env::set_var("NYASH_PARSER_STAGE3", "1");
    std::env::set_var("NYASH_PARSER_ALLOW_SEMICOLON", "1");

    let src = r#"
static box TestExitPhi {
  test() {
    local i = 0
    loop(i < 10) {
      if i == 5 { break }
      i = i + 1
    }
    return i
  }
}
"#;

    println!("=== Test: Single break statement ===");

    // Parse
    let ast = NyashParser::parse_from_string(src)
        .expect("parse failed");

    // Compile
    let mut mc = MirCompiler::with_options(false);
    let cr = mc.compile(ast).expect("compile failed");

    // MIR verification
    let mut verifier = MirVerifier::new();
    if let Err(errors) = verifier.verify_module(&cr.module) {
        for err in &errors {
            eprintln!("❌ MIR verification error: {}", err);
        }
        panic!("❌ MIR verification failed with {} errors", errors.len());
    }
    println!("✅ MIR verification passed");
}

#[test]
fn test_loopform_exit_phi_multiple_breaks() {
    std::env::set_var("NYASH_LOOPFORM_PHI_V2", "1");
    std::env::set_var("NYASH_VM_VERIFY_MIR", "1");
    std::env::set_var("NYASH_LOOPFORM_DEBUG", "1");
    std::env::set_var("NYASH_PARSER_STAGE3", "1");
    std::env::set_var("NYASH_PARSER_ALLOW_SEMICOLON", "1");

    let src = r#"
static box TestMultiBreak {
  test() {
    local i = 0
    loop(i < 10) {
      if i == 3 { break }
      if i == 5 { break }
      i = i + 1
    }
    return i
  }
}
"#;

    println!("=== Test: Multiple break statements ===");

    let ast = NyashParser::parse_from_string(src).expect("parse failed");
    let mut mc = MirCompiler::with_options(false);
    let cr = mc.compile(ast).expect("compile failed");

    let mut verifier = MirVerifier::new();
    if let Err(errors) = verifier.verify_module(&cr.module) {
        for err in &errors {
            eprintln!("❌ MIR verification error: {}", err);
        }
        panic!("❌ MIR verification failed with {} errors", errors.len());
    }
    println!("✅ MIR verification passed");
}

#[test]
fn test_loopform_exit_phi_nested_if_break() {
    std::env::set_var("NYASH_LOOPFORM_PHI_V2", "1");
    std::env::set_var("NYASH_VM_VERIFY_MIR", "1");
    std::env::set_var("NYASH_LOOPFORM_DEBUG", "1");
    std::env::set_var("NYASH_PARSER_STAGE3", "1");
    std::env::set_var("NYASH_PARSER_ALLOW_SEMICOLON", "1");

    let src = r#"
static box TestNestedBreak {
  test() {
    local i = 0
    local found = 0
    loop(i < 10) {
      if i > 5 {
        if i == 7 {
          found = 1
          break
        }
      }
      i = i + 1
    }
    return found
  }
}
"#;

    println!("=== Test: Nested if with break ===");

    let ast = NyashParser::parse_from_string(src).expect("parse failed");
    let mut mc = MirCompiler::with_options(false);
    let cr = mc.compile(ast).expect("compile failed");

    let mut verifier = MirVerifier::new();
    if let Err(errors) = verifier.verify_module(&cr.module) {
        for err in &errors {
            eprintln!("❌ MIR verification error: {}", err);
        }
        panic!("❌ MIR verification failed with {} errors", errors.len());
    }
    println!("✅ MIR verification passed");
}

#[test]
fn test_loopform_exit_phi_multiple_vars() {
    std::env::set_var("NYASH_LOOPFORM_PHI_V2", "1");
    std::env::set_var("NYASH_VM_VERIFY_MIR", "1");
    std::env::set_var("NYASH_LOOPFORM_DEBUG", "1");
    std::env::set_var("NYASH_PARSER_STAGE3", "1");
    std::env::set_var("NYASH_PARSER_ALLOW_SEMICOLON", "1");

    let src = r#"
static box TestMultiVars {
  test() {
    local i = 0
    local sum = 0
    local product = 1
    loop(i < 10) {
      if sum > 20 { break }
      sum = sum + i
      product = product * 2
      i = i + 1
    }
    return sum
  }
}
"#;

    println!("=== Test: Multiple variables with break ===");

    let ast = NyashParser::parse_from_string(src).expect("parse failed");
    let mut mc = MirCompiler::with_options(false);
    let cr = mc.compile(ast).expect("compile failed");

    let mut verifier = MirVerifier::new();
    if let Err(errors) = verifier.verify_module(&cr.module) {
        for err in &errors {
            eprintln!("❌ MIR verification error: {}", err);
        }
        panic!("❌ MIR verification failed with {} errors", errors.len());
    }
    println!("✅ MIR verification passed");
}