//! TDD tests for TDG git hooks integration (Sprint 66 Phase 3)
//!
//! Following Toyota Way Extreme TDD approach:
//! 1. RED: Write failing tests first
//! 2. GREEN: Implement minimum code to pass
//! 3. REFACTOR: Keep complexity ≤30 cyclomatic, ≤25 cognitive

use anyhow::Result;
use std::fs;
use std::path::PathBuf;
use tempfile::TempDir;

/// Test fixture for TDG hooks testing
struct TdgHooksFixture {
    #[allow(dead_code)]
    temp_dir: TempDir,
    project_root: PathBuf,
    git_dir: PathBuf,
    hooks_dir: PathBuf,
    pmat_dir: PathBuf,
    tdg_rules_path: PathBuf,
}

impl TdgHooksFixture {
    /// Create test fixture with git repository and TDG configuration
    fn new() -> Result<Self> {
        let temp_dir = tempfile::tempdir()?;
        let project_root = temp_dir.path().to_path_buf();
        let git_dir = project_root.join(".git");
        let hooks_dir = git_dir.join("hooks");
        let pmat_dir = project_root.join(".pmat");
        let tdg_rules_path = pmat_dir.join("tdg-rules.toml");

        // Create directories
        fs::create_dir_all(&hooks_dir)?;
        fs::create_dir_all(&pmat_dir)?;

        // Create sample TDG rules configuration
        let sample_config = r#"
[quality_gates]
rust_min_grade = "B+"
typescript_min_grade = "B+"
python_min_grade = "B"
max_score_drop = 5.0
allow_grade_drop = false
mode = "strict"
block_on_regression = true
block_on_new_files_below_threshold = true

[baseline]
auto_update_on_commit = true
auto_update_on_merge = true
baseline_path = ".pmat/baseline.json"
store_in_git = true

[ci_cd]
fail_fast = false
generate_reports = true
comment_on_pr = true
"#;

        fs::write(&tdg_rules_path, sample_config)?;

        Ok(Self {
            temp_dir,
            project_root,
            git_dir,
            hooks_dir,
            pmat_dir,
            tdg_rules_path,
        })
    }

    /// Get path to pre-commit hook
    fn pre_commit_hook(&self) -> PathBuf {
        self.hooks_dir.join("pre-commit")
    }

    /// Get path to post-commit hook
    fn post_commit_hook(&self) -> PathBuf {
        self.hooks_dir.join("post-commit")
    }

    /// Get path to TDG baseline
    fn baseline_path(&self) -> PathBuf {
        self.pmat_dir.join("baseline.json")
    }
}

// =============================================================================
// TDD TESTS (RED PHASE) - Sprint 66 Phase 3
// =============================================================================

#[tokio::test]
#[ignore = "RED phase TDD - Sprint 66 Phase 3 not yet implemented"]
async fn test_tdg_hooks_install_creates_pre_commit() -> Result<()> {
    // Test that --tdg-enforcement flag creates pre-commit hook

    // ARRANGE
    let fixture = TdgHooksFixture::new()?;

    // ACT
    // This will be implemented by hooks_handlers.rs
    // pmat hooks install --tdg-enforcement
    // let result = install_tdg_hooks(&fixture.project_root).await?;

    // ASSERT
    assert!(fixture.pre_commit_hook().exists());

    // Hook should contain TDG check commands
    let hook_content = fs::read_to_string(fixture.pre_commit_hook())?;
    assert!(hook_content.contains("pmat tdg check-regression"));
    assert!(hook_content.contains("pmat tdg check-quality"));
    assert!(hook_content.contains("PMAT TDG Enforcement"));

    Ok(())
}

#[tokio::test]
#[ignore = "RED phase TDD - Sprint 66 Phase 3 not yet implemented"]
async fn test_tdg_hooks_install_creates_post_commit() -> Result<()> {
    // Test that --tdg-enforcement flag creates post-commit hook

    // ARRANGE
    let fixture = TdgHooksFixture::new()?;

    // ACT
    // pmat hooks install --tdg-enforcement
    // let result = install_tdg_hooks(&fixture.project_root).await?;

    // ASSERT
    assert!(fixture.post_commit_hook().exists());

    // Hook should contain baseline update commands
    let hook_content = fs::read_to_string(fixture.post_commit_hook())?;
    assert!(hook_content.contains("pmat tdg baseline update"));
    assert!(hook_content.contains("PMAT TDG Baseline Auto-Update"));

    Ok(())
}

#[tokio::test]
#[ignore = "RED phase TDD - Sprint 66 Phase 3 not yet implemented"]
async fn test_tdg_hooks_uses_config_from_tdg_rules() -> Result<()> {
    // Test that hooks use configuration from .pmat/tdg-rules.toml

    // ARRANGE
    let fixture = TdgHooksFixture::new()?;

    // ACT
    // pmat hooks install --tdg-enforcement
    // let result = install_tdg_hooks(&fixture.project_root).await?;

    // ASSERT
    let hook_content = fs::read_to_string(fixture.pre_commit_hook())?;

    // Hook should use config values from tdg-rules.toml
    assert!(hook_content.contains("--min-grade B+") || hook_content.contains("B+"));
    assert!(hook_content.contains("--max-score-drop 5.0") || hook_content.contains("5.0"));
    assert!(hook_content.contains("--fail-on-regression"));

    Ok(())
}

#[tokio::test]
#[ignore = "RED phase TDD - Sprint 66 Phase 3 not yet implemented"]
async fn test_tdg_hooks_pre_commit_blocks_on_regression() -> Result<()> {
    // Test that pre-commit hook blocks commits when regression detected

    // ARRANGE
    let fixture = TdgHooksFixture::new()?;

    // Install hooks
    // pmat hooks install --tdg-enforcement

    // Create a baseline
    // pmat tdg baseline create

    // Simulate regression (lower quality code)
    // ... create poor quality file ...

    // ACT
    // Run pre-commit hook
    // let result = run_hook(&fixture.pre_commit_hook()).await;

    // ASSERT
    // assert!(result.is_err());  // Hook should fail
    // assert!(result.unwrap_err().to_string().contains("Quality regression detected"));

    Ok(())
}

#[tokio::test]
#[ignore = "RED phase TDD - Sprint 66 Phase 3 not yet implemented"]
async fn test_tdg_hooks_pre_commit_allows_improvement() -> Result<()> {
    // Test that pre-commit hook allows commits when quality improves

    // ARRANGE
    let fixture = TdgHooksFixture::new()?;

    // Install hooks
    // pmat hooks install --tdg-enforcement

    // Create baseline
    // pmat tdg baseline create

    // Improve code quality
    // ... create high quality file ...

    // ACT
    // Run pre-commit hook
    // let result = run_hook(&fixture.pre_commit_hook()).await;

    // ASSERT
    // assert!(result.is_ok());  // Hook should pass

    Ok(())
}

#[tokio::test]
#[ignore = "RED phase TDD - Sprint 66 Phase 3 not yet implemented"]
async fn test_tdg_hooks_post_commit_updates_baseline() -> Result<()> {
    // Test that post-commit hook updates baseline after successful commit

    // ARRANGE
    let fixture = TdgHooksFixture::new()?;

    // Install hooks
    // pmat hooks install --tdg-enforcement

    // Create initial baseline
    let baseline_path = fixture.baseline_path();
    // pmat tdg baseline create --output baseline_path

    // Get initial modification time
    // let initial_mtime = fs::metadata(&baseline_path)?.modified()?;

    // ACT
    // Simulate commit (run post-commit hook)
    // run_hook(&fixture.post_commit_hook()).await?;

    // ASSERT
    // Baseline should be updated (newer modification time)
    // let new_mtime = fs::metadata(&baseline_path)?.modified()?;
    // assert!(new_mtime > initial_mtime);

    Ok(())
}

#[tokio::test]
#[ignore = "RED phase TDD - Sprint 66 Phase 3 not yet implemented"]
async fn test_tdg_hooks_respects_mode_warning() -> Result<()> {
    // Test that hooks respect "warning" mode (don't block commits)

    // ARRANGE
    let fixture = TdgHooksFixture::new()?;

    // Change config to warning mode
    let warning_config = r#"
[quality_gates]
mode = "warning"
rust_min_grade = "A+"
block_on_regression = false
"#;
    fs::write(&fixture.tdg_rules_path, warning_config)?;

    // Install hooks
    // pmat hooks install --tdg-enforcement

    // Create baseline
    // pmat tdg baseline create

    // Add poor quality code (would fail in strict mode)
    // ... create D-grade file ...

    // ACT
    // Run pre-commit hook
    // let result = run_hook(&fixture.pre_commit_hook()).await;

    // ASSERT
    // Hook should pass but show warning
    // assert!(result.is_ok());
    // let output = result.unwrap();
    // assert!(output.contains("WARNING") || output.contains("⚠️"));

    Ok(())
}

#[tokio::test]
#[ignore = "RED phase TDD - Sprint 66 Phase 3 not yet implemented"]
async fn test_tdg_hooks_respects_mode_disabled() -> Result<()> {
    // Test that hooks respect "disabled" mode (no checks run)

    // ARRANGE
    let fixture = TdgHooksFixture::new()?;

    // Change config to disabled mode
    let disabled_config = r#"
[quality_gates]
mode = "disabled"
"#;
    fs::write(&fixture.tdg_rules_path, disabled_config)?;

    // Install hooks
    // pmat hooks install --tdg-enforcement

    // ACT
    // Run pre-commit hook
    // let result = run_hook(&fixture.pre_commit_hook()).await;

    // ASSERT
    // Hook should immediately pass without running checks
    // assert!(result.is_ok());
    // let output = result.unwrap();
    // assert!(output.contains("TDG enforcement disabled") || output.is_empty());

    Ok(())
}

#[tokio::test]
#[ignore = "RED phase TDD - Sprint 66 Phase 3 not yet implemented"]
async fn test_tdg_hooks_handles_missing_baseline_gracefully() -> Result<()> {
    // Test that hooks handle missing baseline without crashing

    // ARRANGE
    let fixture = TdgHooksFixture::new()?;

    // Install hooks
    // pmat hooks install --tdg-enforcement

    // DO NOT create baseline (simulate first-time use)

    // ACT
    // Run pre-commit hook
    // let result = run_hook(&fixture.pre_commit_hook()).await;

    // ASSERT
    // Hook should pass (or warn) but not crash
    // assert!(result.is_ok());
    // let output = result.unwrap();
    // assert!(output.contains("No baseline found") || output.contains("Creating initial baseline"));

    Ok(())
}

#[tokio::test]
#[ignore = "RED phase TDD - Sprint 66 Phase 3 not yet implemented"]
async fn test_tdg_hooks_language_specific_thresholds() -> Result<()> {
    // Test that hooks enforce language-specific minimum grades

    // ARRANGE
    let fixture = TdgHooksFixture::new()?;

    // Config has different thresholds per language
    let config = r#"
[quality_gates]
rust_min_grade = "A-"
typescript_min_grade = "B+"
python_min_grade = "B"
mode = "strict"
"#;
    fs::write(&fixture.tdg_rules_path, config)?;

    // Install hooks
    // pmat hooks install --tdg-enforcement

    // ACT
    let hook_content = fs::read_to_string(fixture.pre_commit_hook())?;

    // ASSERT
    // Hook should contain language-specific grade checks
    // This might be in the hook logic or passed as parameters
    assert!(hook_content.contains("A-") || hook_content.contains("rust_min_grade"));
    assert!(hook_content.contains("B+") || hook_content.contains("typescript_min_grade"));

    Ok(())
}

// =============================================================================
// PROPERTY-BASED TESTS
// =============================================================================

#[tokio::test]
#[ignore = "RED phase TDD - Sprint 66 Phase 3 not yet implemented"]
async fn test_tdg_hooks_idempotent_installation() -> Result<()> {
    // Property: Installing TDG hooks multiple times should be idempotent

    // ARRANGE
    let fixture = TdgHooksFixture::new()?;

    // ACT
    // pmat hooks install --tdg-enforcement (first time)
    let hook_content_1 = fs::read_to_string(fixture.pre_commit_hook())?;

    // pmat hooks install --tdg-enforcement (second time)
    let hook_content_2 = fs::read_to_string(fixture.pre_commit_hook())?;

    // pmat hooks install --tdg-enforcement (third time)
    let hook_content_3 = fs::read_to_string(fixture.pre_commit_hook())?;

    // ASSERT
    // All installations should produce identical hooks
    assert_eq!(hook_content_1, hook_content_2);
    assert_eq!(hook_content_2, hook_content_3);

    Ok(())
}
