cargo-coupling 0.3.2

//! Report generation for coupling analysis
//!
//! Generates human-readable reports with actionable refactoring suggestions.

use std::io::{self, Write};

use crate::balance::{
    BalanceScore, IssueThresholds, ProjectBalanceReport, Severity,
    analyze_project_balance_with_thresholds,
};
use crate::metrics::{Distance, IntegrationStrength, ProjectMetrics};

/// Generate a summary report to the given writer
pub fn generate_summary<W: Write>(metrics: &ProjectMetrics, writer: &mut W) -> io::Result<()> {
    generate_summary_with_thresholds(metrics, &IssueThresholds::default(), writer)
}

/// Generate a summary report with custom thresholds
pub fn generate_summary_with_thresholds<W: Write>(
    metrics: &ProjectMetrics,
    thresholds: &IssueThresholds,
    writer: &mut W,
) -> io::Result<()> {
    let report = analyze_project_balance_with_thresholds(metrics, thresholds);
    let dimension_stats = metrics.calculate_dimension_stats();
    let jp = thresholds.japanese;

    let project_name = metrics.workspace_name.as_deref().unwrap_or("project");

    if jp {
        writeln!(writer, "カップリング分析: {}", project_name)?;
        writeln!(writer, "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━")?;
        writeln!(writer)?;
        writeln!(
            writer,
            "評価: {} | スコア: {:.2}/1.00 | モジュール数: {}",
            report.health_grade,
            report.average_score,
            metrics.module_count()
        )?;
    } else {
        writeln!(writer, "Balanced Coupling Analysis: {}", project_name)?;
        writeln!(writer, "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━")?;
        writeln!(writer)?;
        writeln!(
            writer,
            "Grade: {} | Score: {:.2}/1.00 | Modules: {}",
            report.health_grade,
            report.average_score,
            metrics.module_count()
        )?;
    }
    writeln!(writer)?;

    // 3-Dimensional Analysis
    if !metrics.couplings.is_empty() {
        // Strength distribution
        let (intr_pct, func_pct, model_pct, contract_pct) = dimension_stats.strength_percentages();
        // Distance distribution
        let (same_pct, diff_pct, ext_pct) = dimension_stats.distance_percentages();
        // Volatility distribution
        let (low_pct, med_pct, high_pct) = dimension_stats.volatility_percentages();

        if jp {
            writeln!(writer, "3次元分析:")?;
            writeln!(
                writer,
                "  結合強度: Contract {:.0}% / Model {:.0}% / Functional {:.0}% / Intrusive {:.0}%",
                contract_pct, model_pct, func_pct, intr_pct
            )?;
            writeln!(
                writer,
                "           (トレイト)   (型)      (関数)        (内部アクセス)"
            )?;
            writeln!(
                writer,
                "  距離:     同一モジュール {:.0}% / 別モジュール {:.0}% / 外部 {:.0}%",
                same_pct, diff_pct, ext_pct
            )?;
            writeln!(
                writer,
                "  変更頻度: 低 {:.0}% / 中 {:.0}% / 高 {:.0}%",
                low_pct, med_pct, high_pct
            )?;
        } else {
            writeln!(writer, "3-Dimensional Analysis:")?;
            writeln!(
                writer,
                "  Strength:   Contract {:.0}% / Model {:.0}% / Functional {:.0}% / Intrusive {:.0}%",
                contract_pct, model_pct, func_pct, intr_pct
            )?;
            writeln!(
                writer,
                "  Distance:   Same {:.0}% / Different {:.0}% / External {:.0}%",
                same_pct, diff_pct, ext_pct
            )?;
            writeln!(
                writer,
                "  Volatility: Low {:.0}% / Medium {:.0}% / High {:.0}%",
                low_pct, med_pct, high_pct
            )?;
        }
        writeln!(writer)?;

        // Balance Classification
        if jp {
            writeln!(writer, "バランス状態:")?;
        } else {
            writeln!(writer, "Balance State:")?;
        }
        let bc = &dimension_stats.balance_counts;
        let total = dimension_stats.total();
        if bc.high_cohesion > 0 {
            if jp {
                writeln!(
                    writer,
                    "  ✅ 高凝集 (強い結合 + 近い距離): {} ({:.0}%) ← 理想的",
                    bc.high_cohesion,
                    bc.high_cohesion as f64 / total as f64 * 100.0
                )?;
            } else {
                writeln!(
                    writer,
                    "  ✅ High Cohesion (strong+close): {} ({:.0}%)",
                    bc.high_cohesion,
                    bc.high_cohesion as f64 / total as f64 * 100.0
                )?;
            }
        }
        if bc.loose_coupling > 0 {
            if jp {
                writeln!(
                    writer,
                    "  ✅ 疎結合 (弱い結合 + 遠い距離): {} ({:.0}%) ← 理想的",
                    bc.loose_coupling,
                    bc.loose_coupling as f64 / total as f64 * 100.0
                )?;
            } else {
                writeln!(
                    writer,
                    "  ✅ Loose Coupling (weak+far): {} ({:.0}%)",
                    bc.loose_coupling,
                    bc.loose_coupling as f64 / total as f64 * 100.0
                )?;
            }
        }
        if bc.acceptable > 0 {
            if jp {
                writeln!(
                    writer,
                    "  🤔 許容可能 (強い結合 + 遠い距離 + 安定): {} ({:.0}%)",
                    bc.acceptable,
                    bc.acceptable as f64 / total as f64 * 100.0
                )?;
            } else {
                writeln!(
                    writer,
                    "  🤔 Acceptable (strong+far+stable): {} ({:.0}%)",
                    bc.acceptable,
                    bc.acceptable as f64 / total as f64 * 100.0
                )?;
            }
        }
        if bc.pain > 0 {
            if jp {
                writeln!(
                    writer,
                    "  ❌ 要リファクタリング (強い結合 + 遠い距離 + 頻繁に変更): {} ({:.0}%)",
                    bc.pain,
                    bc.pain as f64 / total as f64 * 100.0
                )?;
            } else {
                writeln!(
                    writer,
                    "  ❌ Needs Refactoring (strong+far+volatile): {} ({:.0}%)",
                    bc.pain,
                    bc.pain as f64 / total as f64 * 100.0
                )?;
            }
        }
        if bc.local_complexity > 0 {
            if jp {
                writeln!(
                    writer,
                    "  🔍 局所的複雑性 (弱い結合 + 近い距離): {} ({:.0}%)",
                    bc.local_complexity,
                    bc.local_complexity as f64 / total as f64 * 100.0
                )?;
            } else {
                writeln!(
                    writer,
                    "  🔍 Local Complexity (weak+close): {} ({:.0}%)",
                    bc.local_complexity,
                    bc.local_complexity as f64 / total as f64 * 100.0
                )?;
            }
        }
        writeln!(writer)?;
    }

    // Issue breakdown
    let critical = *report
        .issues_by_severity
        .get(&Severity::Critical)
        .unwrap_or(&0);
    let high = *report.issues_by_severity.get(&Severity::High).unwrap_or(&0);
    let medium = *report
        .issues_by_severity
        .get(&Severity::Medium)
        .unwrap_or(&0);
    let low = *report.issues_by_severity.get(&Severity::Low).unwrap_or(&0);

    if critical > 0 || high > 0 || medium > 0 || low > 0 {
        if jp {
            writeln!(writer, "検出された問題:")?;
            if critical > 0 {
                writeln!(writer, "  🔴 緊急: {} 件 (すぐに修正が必要)", critical)?;
            }
            if high > 0 {
                writeln!(writer, "  🟠 高: {} 件 (早めに対処)", high)?;
            }
            if medium > 0 {
                writeln!(writer, "  🟡 中: {} 件", medium)?;
            }
            if low > 0 {
                writeln!(writer, "  ⚪ 低: {} 件", low)?;
            }
        } else {
            writeln!(writer, "Detected Issues:")?;
            if critical > 0 {
                writeln!(writer, "  🔴 Critical: {} (must fix)", critical)?;
            }
            if high > 0 {
                writeln!(writer, "  🟠 High: {} (should fix)", high)?;
            }
            if medium > 0 {
                writeln!(writer, "  🟡 Medium: {}", medium)?;
            }
            if low > 0 {
                writeln!(writer, "  ⚪ Low: {}", low)?;
            }
        }
        writeln!(writer)?;
    } else if thresholds.strict_mode {
        if jp {
            writeln!(writer, "検出された問題: なし (--all で低優先度も表示)\n")?;
        } else {
            writeln!(
                writer,
                "Detected Issues: None (use --all to see Low severity)\n"
            )?;
        }
    }

    // Top priority if any
    if !report.top_priorities.is_empty() {
        if jp {
            writeln!(writer, "優先的に対処すべき問題:")?;
            for issue in report.top_priorities.iter().take(3) {
                let issue_jp = issue_type_japanese(issue.issue_type);
                writeln!(writer, "  - {} | {}", issue_jp, issue.source)?;
                writeln!(
                    writer,
                    "    → {}",
                    refactoring_action_japanese(&issue.refactoring)
                )?;
            }
        } else {
            writeln!(writer, "Top Priorities:")?;
            for issue in report.top_priorities.iter().take(3) {
                writeln!(
                    writer,
                    "  - [{}] {} → {}",
                    issue.severity, issue.source, issue.target
                )?;
            }
        }
        writeln!(writer)?;
    }

    // Rust Design Quality (newtype usage)
    let newtype_count = metrics.total_newtype_count();
    let type_count = metrics.total_type_count();
    if type_count > 0 {
        let newtype_ratio = metrics.newtype_ratio() * 100.0;
        if jp {
            let quality = if newtype_ratio >= 20.0 {
                "✅ 良好"
            } else if newtype_ratio >= 10.0 {
                "🤔 増やすことを検討"
            } else {
                "⚠️ 少ない"
            };
            writeln!(
                writer,
                "Rustパターン: newtype使用率 {}/{} ({:.0}%) - {}",
                newtype_count, type_count, newtype_ratio, quality
            )?;
        } else {
            let quality = if newtype_ratio >= 20.0 {
                "✅ Good"
            } else if newtype_ratio >= 10.0 {
                "🤔 Consider more"
            } else {
                "⚠️ Low usage"
            };
            writeln!(
                writer,
                "Rust Patterns: Newtype usage: {}/{} ({:.0}%) - {}",
                newtype_count, type_count, newtype_ratio, quality
            )?;
        }
        writeln!(writer)?;
    }

    // Circular dependencies
    let circular = metrics.circular_dependency_summary();
    if circular.total_cycles > 0 {
        if jp {
            writeln!(
                writer,
                "⚠️ 循環依存: {} サイクル ({} モジュール)",
                circular.total_cycles, circular.affected_modules
            )?;
        } else {
            writeln!(
                writer,
                "⚠️ Circular Dependencies: {} cycles ({} modules)",
                circular.total_cycles, circular.affected_modules
            )?;
        }
    }

    // Design decision guide (Japanese only, for educational purposes)
    if jp {
        writeln!(writer)?;
        writeln!(writer, "設計判断ガイド (Khononov):")?;
        writeln!(writer, "  ✅ 強い結合 + 近い距離 → 高凝集 (理想的)")?;
        writeln!(writer, "  ✅ 弱い結合 + 遠い距離 → 疎結合 (理想的)")?;
        writeln!(writer, "  🤔 強い結合 + 遠い距離 + 安定 → 許容可能")?;
        writeln!(
            writer,
            "  ❌ 強い結合 + 遠い距離 + 頻繁に変更 → 要リファクタリング"
        )?;
    }

    Ok(())
}

/// Get Japanese translation for issue type
fn issue_type_japanese(issue_type: crate::balance::IssueType) -> &'static str {
    use crate::balance::IssueType;
    match issue_type {
        IssueType::GlobalComplexity => "グローバル複雑性 (遠距離への強い依存)",
        IssueType::CascadingChangeRisk => "変更波及リスク (頻繁に変わるものへの依存)",
        IssueType::InappropriateIntimacy => "不適切な親密さ (内部実装への依存)",
        IssueType::HighEfferentCoupling => "出力依存過多 (多くのモジュールに依存)",
        IssueType::HighAfferentCoupling => "入力依存過多 (多くのモジュールから依存される)",
        IssueType::UnnecessaryAbstraction => "過剰な抽象化",
        IssueType::CircularDependency => "循環依存",
        IssueType::ShallowModule => "浅いモジュール",
        IssueType::PassThroughMethod => "パススルーメソッド",
        IssueType::HighCognitiveLoad => "高認知負荷",
        IssueType::GodModule => "神モジュール (責務が多すぎる)",
        IssueType::PublicFieldExposure => "公開フィールド (getterを検討)",
        IssueType::PrimitiveObsession => "プリミティブ過多 (newtypeを検討)",
    }
}

/// Get Japanese translation for refactoring action
fn refactoring_action_japanese(action: &crate::balance::RefactoringAction) -> String {
    use crate::balance::RefactoringAction;
    match action {
        RefactoringAction::IntroduceTrait { suggested_name, .. } => {
            format!("トレイト `{}` を導入して抽象化する", suggested_name)
        }
        RefactoringAction::MoveCloser { target_location } => {
            format!("`{}` に移動して距離を縮める", target_location)
        }
        RefactoringAction::ExtractAdapter { adapter_name, .. } => {
            format!("アダプタ `{}` を抽出する", adapter_name)
        }
        RefactoringAction::SplitModule { suggested_modules } => {
            format!("モジュールを分割: {}", suggested_modules.join(", "))
        }
        RefactoringAction::SimplifyAbstraction { .. } => "抽象化を簡素化する".to_string(),
        RefactoringAction::BreakCycle {
            suggested_direction,
        } => {
            format!("循環を断つ: {}", suggested_direction)
        }
        RefactoringAction::StabilizeInterface { interface_name } => {
            format!("安定したインターフェース `{}` を追加", interface_name)
        }
        RefactoringAction::General { action } => action.clone(),
        RefactoringAction::AddGetters { .. } => "getterメソッドを追加する".to_string(),
        RefactoringAction::IntroduceNewtype {
            suggested_name,
            wrapped_type,
        } => {
            format!(
                "newtype `struct {}({})` を導入",
                suggested_name, wrapped_type
            )
        }
    }
}

/// Generate a full Markdown report with refactoring suggestions
pub fn generate_report<W: Write>(metrics: &ProjectMetrics, writer: &mut W) -> io::Result<()> {
    generate_report_with_thresholds(metrics, &IssueThresholds::default(), writer)
}

/// Generate a full Markdown report with custom thresholds
pub fn generate_report_with_thresholds<W: Write>(
    metrics: &ProjectMetrics,
    thresholds: &IssueThresholds,
    writer: &mut W,
) -> io::Result<()> {
    let report = analyze_project_balance_with_thresholds(metrics, thresholds);

    writeln!(writer, "# Coupling Analysis Report\n")?;

    // Executive Summary
    write_executive_summary(metrics, &report, writer)?;

    // Refactoring Priorities (if any issues)
    if !report.issues.is_empty() {
        write_refactoring_priorities(&report, writer)?;
    }

    // Detailed Issues by Type
    write_issues_by_type(&report, writer)?;

    // Coupling details
    write_coupling_section(metrics, writer)?;

    // Module analysis
    write_module_section(metrics, writer)?;

    // Volatility section
    write_volatility_section(metrics, writer)?;

    // Circular dependency section
    write_circular_dependencies_section(metrics, writer)?;

    // Best practices
    write_best_practices(writer)?;

    Ok(())
}

fn write_executive_summary<W: Write>(
    metrics: &ProjectMetrics,
    report: &ProjectBalanceReport,
    writer: &mut W,
) -> io::Result<()> {
    writeln!(writer, "## Executive Summary\n")?;

    // Health Grade with emoji
    let grade_emoji = match report.health_grade {
        crate::balance::HealthGrade::S => "⚠️",
        crate::balance::HealthGrade::A => "🟢",
        crate::balance::HealthGrade::B => "🟢",
        crate::balance::HealthGrade::C => "🟡",
        crate::balance::HealthGrade::D => "🟠",
        crate::balance::HealthGrade::F => "🔴",
    };

    writeln!(
        writer,
        "**Health Grade**: {} {}\n",
        grade_emoji, report.health_grade
    )?;

    writeln!(writer, "| Metric | Value |")?;
    writeln!(writer, "|--------|-------|")?;
    writeln!(writer, "| Files Analyzed | {} |", metrics.total_files)?;
    writeln!(writer, "| Total Modules | {} |", metrics.module_count())?;
    writeln!(writer, "| Total Couplings | {} |", report.total_couplings)?;
    writeln!(
        writer,
        "| Balance Score | {:.2}/1.00 |",
        report.average_score
    )?;
    writeln!(
        writer,
        "| Balanced | {} ({:.0}%) |",
        report.balanced_count,
        if report.total_couplings > 0 {
            (report.balanced_count as f64 / report.total_couplings as f64) * 100.0
        } else {
            100.0
        }
    )?;
    writeln!(
        writer,
        "| Needs Refactoring | {} |",
        report.needs_refactoring
    )?;
    writeln!(writer)?;

    // Issue counts
    let critical = *report
        .issues_by_severity
        .get(&Severity::Critical)
        .unwrap_or(&0);
    let high = *report.issues_by_severity.get(&Severity::High).unwrap_or(&0);
    let medium = *report
        .issues_by_severity
        .get(&Severity::Medium)
        .unwrap_or(&0);
    let low = *report.issues_by_severity.get(&Severity::Low).unwrap_or(&0);

    if critical > 0 || high > 0 {
        writeln!(writer, "**⚠️ Action Required**\n")?;
        if critical > 0 {
            writeln!(
                writer,
                "- 🔴 **{} Critical** issues must be fixed immediately",
                critical
            )?;
        }
        if high > 0 {
            writeln!(
                writer,
                "- 🟠 **{} High** priority issues should be addressed soon",
                high
            )?;
        }
        if medium > 0 {
            writeln!(writer, "- 🟡 {} Medium priority issues to review", medium)?;
        }
        if low > 0 {
            writeln!(writer, "- {} Low priority suggestions", low)?;
        }
        writeln!(writer)?;
    } else if medium > 0 {
        writeln!(
            writer,
            "**ℹ️ Review Suggested**: {} issues to consider.\n",
            medium + low
        )?;
    } else {
        writeln!(
            writer,
            "**✅ Good Health**: No significant coupling issues detected.\n"
        )?;
    }

    Ok(())
}

fn write_refactoring_priorities<W: Write>(
    report: &ProjectBalanceReport,
    writer: &mut W,
) -> io::Result<()> {
    writeln!(writer, "## 🔧 Refactoring Priorities\n")?;

    // Show top 5 priority issues with concrete actions
    writeln!(writer, "### Immediate Actions\n")?;

    let priority_issues: Vec<_> = report
        .issues
        .iter()
        .filter(|i| i.severity >= Severity::Medium)
        .take(5)
        .collect();

    if priority_issues.is_empty() {
        writeln!(writer, "No immediate refactoring actions required.\n")?;
        return Ok(());
    }

    for (i, issue) in priority_issues.iter().enumerate() {
        let severity_icon = match issue.severity {
            Severity::Critical => "🔴",
            Severity::High => "🟠",
            Severity::Medium => "🟡",
            Severity::Low => "⚪",
        };

        writeln!(
            writer,
            "**{}. {} `{}` → `{}`**\n",
            i + 1,
            severity_icon,
            issue.source,
            issue.target
        )?;

        writeln!(
            writer,
            "- **Issue**: {} - {}",
            issue.issue_type, issue.description
        )?;
        writeln!(writer, "- **Why**: {}", issue.issue_type.description())?;
        writeln!(writer, "- **Action**: {}", issue.refactoring)?;
        writeln!(writer, "- **Balance Score**: {:.2}\n", issue.balance_score)?;
    }

    Ok(())
}

fn write_issues_by_type<W: Write>(report: &ProjectBalanceReport, writer: &mut W) -> io::Result<()> {
    if report.issues.is_empty() {
        return Ok(());
    }

    writeln!(writer, "## Issues by Category\n")?;

    let grouped = report.issues_grouped_by_type();

    // Order by severity of issues in each group
    let mut issue_types: Vec<_> = grouped.keys().collect();
    issue_types.sort_by(|a, b| {
        let a_max = grouped
            .get(a)
            .and_then(|v| v.iter().map(|i| i.severity).max());
        let b_max = grouped
            .get(b)
            .and_then(|v| v.iter().map(|i| i.severity).max());
        b_max.cmp(&a_max)
    });

    for issue_type in issue_types {
        if let Some(issues) = grouped.get(issue_type) {
            let count = issues.len();

            writeln!(writer, "### {} ({} instances)\n", issue_type, count)?;
            writeln!(writer, "> {}\n", issue_type.description())?;

            // Show up to 5 examples
            writeln!(writer, "| Severity | Source | Target | Action |")?;
            writeln!(writer, "|----------|--------|--------|--------|")?;

            for issue in issues.iter().take(5) {
                let action_short = format!("{}", issue.refactoring);
                let action_truncated = if action_short.len() > 40 {
                    format!("{}...", &action_short[..40])
                } else {
                    action_short
                };
                writeln!(
                    writer,
                    "| {} | `{}` | `{}` | {} |",
                    issue.severity,
                    truncate_path(&issue.source, 25),
                    truncate_path(&issue.target, 25),
                    action_truncated
                )?;
            }

            if count > 5 {
                writeln!(writer, "\n*...and {} more instances*", count - 5)?;
            }
            writeln!(writer)?;
        }
    }

    Ok(())
}

fn write_coupling_section<W: Write>(metrics: &ProjectMetrics, writer: &mut W) -> io::Result<()> {
    if metrics.couplings.is_empty() {
        return Ok(());
    }

    writeln!(writer, "## Coupling Distribution\n")?;

    // Strength distribution
    writeln!(writer, "### By Integration Strength\n")?;
    writeln!(writer, "| Strength | Count | % | Description |")?;
    writeln!(writer, "|----------|-------|---|-------------|")?;

    let total = metrics.couplings.len() as f64;
    for (strength, label, desc) in [
        (
            IntegrationStrength::Contract,
            "Contract",
            "Depends on traits/interfaces only",
        ),
        (
            IntegrationStrength::Model,
            "Model",
            "Uses data types/structs",
        ),
        (
            IntegrationStrength::Functional,
            "Functional",
            "Calls specific functions",
        ),
        (
            IntegrationStrength::Intrusive,
            "Intrusive",
            "Accesses internal details",
        ),
    ] {
        let count = metrics
            .couplings
            .iter()
            .filter(|c| c.strength == strength)
            .count();
        let pct = (count as f64 / total) * 100.0;
        writeln!(writer, "| {} | {} | {:.0}% | {} |", label, count, pct, desc)?;
    }
    writeln!(writer)?;

    // Distance distribution
    writeln!(writer, "### By Distance\n")?;
    writeln!(writer, "| Distance | Count | % |")?;
    writeln!(writer, "|----------|-------|---|")?;

    for (distance, label) in [
        (Distance::SameModule, "Same Module (close)"),
        (Distance::DifferentModule, "Different Module"),
        (Distance::DifferentCrate, "External Crate (far)"),
    ] {
        let count = metrics
            .couplings
            .iter()
            .filter(|c| c.distance == distance)
            .count();
        let pct = (count as f64 / total) * 100.0;
        writeln!(writer, "| {} | {} | {:.0}% |", label, count, pct)?;
    }
    writeln!(writer)?;

    // Volatility distribution (only for internal couplings where we have git data)
    let internal_couplings: Vec<_> = metrics
        .couplings
        .iter()
        .filter(|c| c.distance != Distance::DifferentCrate)
        .collect();

    if !internal_couplings.is_empty() {
        let internal_total = internal_couplings.len() as f64;
        writeln!(writer, "### By Volatility (Internal Couplings)\n")?;
        writeln!(writer, "| Volatility | Count | % | Impact on Balance |")?;
        writeln!(writer, "|------------|-------|---|-------------------|")?;

        for (volatility, label, impact) in [
            (
                crate::metrics::Volatility::Low,
                "Low (rarely changes)",
                "No penalty",
            ),
            (
                crate::metrics::Volatility::Medium,
                "Medium (sometimes changes)",
                "Moderate penalty",
            ),
            (
                crate::metrics::Volatility::High,
                "High (frequently changes)",
                "Significant penalty",
            ),
        ] {
            let count = internal_couplings
                .iter()
                .filter(|c| c.volatility == volatility)
                .count();
            let pct = (count as f64 / internal_total) * 100.0;
            writeln!(
                writer,
                "| {} | {} | {:.0}% | {} |",
                label, count, pct, impact
            )?;
        }
        writeln!(writer)?;
    }

    // Worst balanced couplings
    writeln!(writer, "### Worst Balanced Couplings\n")?;

    let mut couplings_with_scores: Vec<_> = metrics
        .couplings
        .iter()
        .map(|c| (c, BalanceScore::calculate(c)))
        .collect();

    couplings_with_scores.sort_by(|a, b| a.1.score.partial_cmp(&b.1.score).unwrap());

    writeln!(
        writer,
        "| Source | Target | Strength | Distance | Volatility | Score | Status |"
    )?;
    writeln!(
        writer,
        "|--------|--------|----------|----------|------------|-------|--------|"
    )?;

    for (coupling, score) in couplings_with_scores.iter().take(15) {
        let strength_str = match coupling.strength {
            IntegrationStrength::Contract => "Contract",
            IntegrationStrength::Model => "Model",
            IntegrationStrength::Functional => "Functional",
            IntegrationStrength::Intrusive => "Intrusive",
        };
        let distance_str = match coupling.distance {
            Distance::SameFunction => "Same Fn",
            Distance::SameModule => "Same Mod",
            Distance::DifferentModule => "Diff Mod",
            Distance::DifferentCrate => "External",
        };
        let volatility_str = match coupling.volatility {
            crate::metrics::Volatility::Low => "Low",
            crate::metrics::Volatility::Medium => "Med",
            crate::metrics::Volatility::High => "High",
        };
        let status = match score.interpretation {
            crate::balance::BalanceInterpretation::Balanced => "✅ Balanced",
            crate::balance::BalanceInterpretation::Acceptable => "✅ OK",
            crate::balance::BalanceInterpretation::NeedsReview => "🟡 Review",
            crate::balance::BalanceInterpretation::NeedsRefactoring => "🟠 Refactor",
            crate::balance::BalanceInterpretation::Critical => "🔴 Critical",
        };

        writeln!(
            writer,
            "| `{}` | `{}` | {} | {} | {} | {:.2} | {} |",
            truncate_path(&coupling.source, 20),
            truncate_path(&coupling.target, 20),
            strength_str,
            distance_str,
            volatility_str,
            score.score,
            status
        )?;
    }

    if couplings_with_scores.len() > 15 {
        writeln!(
            writer,
            "\n*Showing 15 of {} couplings*",
            couplings_with_scores.len()
        )?;
    }
    writeln!(writer)?;

    Ok(())
}

fn write_module_section<W: Write>(metrics: &ProjectMetrics, writer: &mut W) -> io::Result<()> {
    if metrics.modules.is_empty() {
        return Ok(());
    }

    writeln!(writer, "## Module Statistics\n")?;

    writeln!(
        writer,
        "| Module | Trait Impl | Inherent Impl | Internal Deps | External Deps |"
    )?;
    writeln!(
        writer,
        "|--------|------------|---------------|---------------|---------------|"
    )?;

    let mut modules: Vec<_> = metrics.modules.iter().collect();
    modules.sort_by(|a, b| {
        let a_deps = a.1.internal_deps.len() + a.1.external_deps.len();
        let b_deps = b.1.internal_deps.len() + b.1.external_deps.len();
        b_deps.cmp(&a_deps)
    });

    for (name, module) in modules.iter().take(20) {
        writeln!(
            writer,
            "| `{}` | {} | {} | {} | {} |",
            truncate_path(name, 30),
            module.trait_impl_count,
            module.inherent_impl_count,
            module.internal_deps.len(),
            module.external_deps.len()
        )?;
    }

    if modules.len() > 20 {
        writeln!(writer, "\n*Showing top 20 of {} modules*", modules.len())?;
    }
    writeln!(writer)?;

    Ok(())
}

fn write_volatility_section<W: Write>(metrics: &ProjectMetrics, writer: &mut W) -> io::Result<()> {
    writeln!(writer, "## Volatility Analysis\n")?;

    if metrics.file_changes.is_empty() {
        writeln!(
            writer,
            "*Git history analysis not available. Run in a git repository for volatility data.*\n"
        )?;
        return Ok(());
    }

    let mut high_vol: Vec<_> = metrics
        .file_changes
        .iter()
        .filter(|&(_, count)| *count > 10)
        .collect();

    high_vol.sort_by(|a, b| b.1.cmp(a.1));

    if high_vol.is_empty() {
        writeln!(
            writer,
            "No high volatility files detected (threshold: >10 changes).\n"
        )?;
    } else {
        writeln!(writer, "### High Volatility Files\n")?;
        writeln!(
            writer,
            "⚠️ Strong coupling to these files increases cascading change risk.\n"
        )?;
        writeln!(writer, "| File | Changes |")?;
        writeln!(writer, "|------|---------|")?;
        for (file, count) in high_vol.iter().take(10) {
            writeln!(writer, "| `{}` | {} |", file, count)?;
        }
        writeln!(writer)?;
    }

    Ok(())
}

fn write_circular_dependencies_section<W: Write>(
    metrics: &ProjectMetrics,
    writer: &mut W,
) -> io::Result<()> {
    let summary = metrics.circular_dependency_summary();

    if summary.total_cycles == 0 {
        writeln!(writer, "## Circular Dependencies\n")?;
        writeln!(writer, "✅ No circular dependencies detected.\n")?;
        return Ok(());
    }

    writeln!(writer, "## ⚠️ Circular Dependencies\n")?;
    writeln!(
        writer,
        "Found **{} circular dependency cycle(s)** involving **{} modules**.\n",
        summary.total_cycles, summary.affected_modules
    )?;

    writeln!(
        writer,
        "Circular dependencies make code harder to understand, test, and maintain."
    )?;
    writeln!(writer, "Consider breaking cycles by:\n")?;
    writeln!(writer, "1. Extracting shared types into a separate module")?;
    writeln!(writer, "2. Inverting dependencies using traits/interfaces")?;
    writeln!(writer, "3. Moving functionality to reduce coupling\n")?;

    writeln!(writer, "### Detected Cycles\n")?;

    for (i, cycle) in summary.cycles.iter().take(10).enumerate() {
        let cycle_str = cycle.join(" → ");
        writeln!(
            writer,
            "{}. `{}` → `{}`",
            i + 1,
            cycle_str,
            cycle.first().unwrap_or(&"?".to_string())
        )?;
    }

    if summary.cycles.len() > 10 {
        writeln!(
            writer,
            "\n*...and {} more cycles*",
            summary.cycles.len() - 10
        )?;
    }
    writeln!(writer)?;

    Ok(())
}

fn write_best_practices<W: Write>(writer: &mut W) -> io::Result<()> {
    writeln!(writer, "## Balance Guidelines\n")?;

    writeln!(
        writer,
        "The goal is **balanced coupling**, not zero coupling.\n"
    )?;

    writeln!(writer, "### Ideal Patterns ✅\n")?;
    writeln!(writer, "| Pattern | Example | Why It Works |")?;
    writeln!(writer, "|---------|---------|--------------|")?;
    writeln!(
        writer,
        "| Strong + Close | `impl` blocks in same module | Cohesion within boundaries |"
    )?;
    writeln!(
        writer,
        "| Weak + Far | Trait impl for external crate | Loose coupling across boundaries |"
    )?;
    writeln!(writer)?;

    writeln!(writer, "### Problematic Patterns ❌\n")?;
    writeln!(writer, "| Pattern | Problem | Solution |")?;
    writeln!(writer, "|---------|---------|----------|")?;
    writeln!(
        writer,
        "| Strong + Far | Global complexity | Introduce adapter or move closer |"
    )?;
    writeln!(
        writer,
        "| Strong + Volatile | Cascading changes | Add stable interface |"
    )?;
    writeln!(
        writer,
        "| Intrusive + Cross-boundary | Encapsulation violation | Extract trait API |"
    )?;
    writeln!(writer)?;

    Ok(())
}

fn truncate_path(path: &str, max_len: usize) -> String {
    if path.len() <= max_len {
        path.to_string()
    } else {
        format!("...{}", &path[path.len() - max_len + 3..])
    }
}

/// Generate AI-friendly output format for coding agents
///
/// This format is designed to be:
/// 1. Concise and structured for LLM consumption
/// 2. Actionable with specific file/module references
/// 3. Copy-paste ready for AI refactoring prompts
pub fn generate_ai_output<W: Write>(metrics: &ProjectMetrics, writer: &mut W) -> io::Result<()> {
    generate_ai_output_with_thresholds(metrics, &IssueThresholds::default(), writer)
}

/// Generate AI-friendly output with custom thresholds
pub fn generate_ai_output_with_thresholds<W: Write>(
    metrics: &ProjectMetrics,
    thresholds: &IssueThresholds,
    writer: &mut W,
) -> io::Result<()> {
    let report = analyze_project_balance_with_thresholds(metrics, thresholds);

    let project_name = metrics.workspace_name.as_deref().unwrap_or("project");
    writeln!(writer, "Coupling Issues in {}:", project_name)?;
    writeln!(
        writer,
        "────────────────────────────────────────────────────────────"
    )?;
    writeln!(writer)?;

    // Summary line
    writeln!(
        writer,
        "Grade: {} | Score: {:.2} | Issues: {} High, {} Medium",
        report.health_grade,
        report.average_score,
        report.issues_by_severity.get(&Severity::High).unwrap_or(&0),
        report
            .issues_by_severity
            .get(&Severity::Medium)
            .unwrap_or(&0)
    )?;
    writeln!(writer)?;

    // List issues in a structured format
    if report.issues.is_empty() {
        writeln!(writer, "✅ No coupling issues detected.")?;
        writeln!(writer)?;
    } else {
        writeln!(writer, "Issues:")?;
        writeln!(writer)?;

        for (i, issue) in report.issues.iter().take(10).enumerate() {
            let severity_marker = match issue.severity {
                Severity::Critical => "🔴",
                Severity::High => "🟠",
                Severity::Medium => "🟡",
                Severity::Low => "⚪",
            };

            writeln!(
                writer,
                "{}. {} {} → {}",
                i + 1,
                severity_marker,
                issue.source,
                issue.target
            )?;
            writeln!(writer, "   Type: {}", issue.issue_type)?;
            writeln!(writer, "   Problem: {}", issue.description)?;
            writeln!(writer, "   Fix: {}", issue.refactoring)?;
            writeln!(writer)?;
        }

        if report.issues.len() > 10 {
            writeln!(writer, "... and {} more issues", report.issues.len() - 10)?;
            writeln!(writer)?;
        }
    }

    // Circular dependencies (critical for AI to understand)
    let circular = metrics.circular_dependency_summary();
    if circular.total_cycles > 0 {
        writeln!(
            writer,
            "Circular Dependencies ({} cycles):",
            circular.total_cycles
        )?;
        for cycle in circular.cycles.iter().take(5) {
            writeln!(
                writer,
                "  {} → {}",
                cycle.join(" → "),
                cycle.first().unwrap_or(&"?".to_string())
            )?;
        }
        writeln!(writer)?;
    }

    // only show ai refactor advice if there is something to refactor
    if !report.issues.is_empty() || circular.total_cycles > 0 {
        writeln!(
            writer,
            "────────────────────────────────────────────────────────────"
        )?;
        writeln!(writer)?;

        // AI prompt suggestion
        writeln!(
            writer,
            "💡 To refactor with AI, copy this output and use this prompt:"
        )?;
        writeln!(writer)?;
        writeln!(writer, "```")?;
        writeln!(
            writer,
            "Analyze the coupling issues above from `cargo coupling --ai`. "
        )?;
        writeln!(
            writer,
            "For each issue, suggest specific code changes to reduce coupling."
        )?;
        writeln!(
            writer,
            "Focus on introducing traits, moving code closer, or breaking circular dependencies."
        )?;
        writeln!(writer, "```")?;
    }

    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::path::PathBuf;

    #[test]
    fn test_generate_summary() {
        let metrics = ProjectMetrics::new();
        let mut output = Vec::new();

        let result = generate_summary(&metrics, &mut output);
        assert!(result.is_ok());

        let output_str = String::from_utf8(output).unwrap();
        assert!(output_str.contains("Balanced Coupling Analysis"));
        assert!(output_str.contains("Grade:"));
    }

    #[test]
    fn test_generate_report() {
        let metrics = ProjectMetrics::new();
        let mut output = Vec::new();

        let result = generate_report(&metrics, &mut output);
        assert!(result.is_ok());

        let output_str = String::from_utf8(output).unwrap();
        assert!(output_str.contains("# Coupling Analysis Report"));
        assert!(output_str.contains("Executive Summary"));
    }

    #[test]
    fn test_generate_report_with_modules() {
        use crate::metrics::ModuleMetrics;

        let mut metrics = ProjectMetrics::new();
        let mut module = ModuleMetrics::new(PathBuf::from("lib.rs"), "lib".to_string());
        module.trait_impl_count = 3;
        module.inherent_impl_count = 2;
        metrics.add_module(module);

        let mut output = Vec::new();
        let result = generate_report(&metrics, &mut output);
        assert!(result.is_ok());

        let output_str = String::from_utf8(output).unwrap();
        assert!(output_str.contains("Module Statistics"));
    }

    #[test]
    fn test_truncate_path() {
        assert_eq!(truncate_path("short", 10), "short");
        assert_eq!(
            truncate_path("this_is_a_very_long_path", 15),
            "...ry_long_path"
        );
    }
}