//! Built-in best-practice tools for zesdex.
//!
//! These tools allow the LLM agent to run architecture audits, code-quality
//! scans, commit-message validation, and skill lookups — all as compiled-in
//! features of the zesdex binary.
//!
//! # Tools
//!
//! | Tool name | Action |
//! |-----------|--------|
//! | `best_practice` | Run architecture audit, code-quality scan, or skill lookup |
//! | `commit_convention` | Validate or suggest commit messages |

use crate::best_practice::BestPracticeEngine;
use crate::tools::{arg_str, Tool, ToolCtx};
use anyhow::{bail, Result};
use serde_json::{json, Value};
use std::sync::OnceLock;
use tracing::instrument;

// ---------------------------------------------------------------------------
// Shared engine instance (lazy, created once)
// ---------------------------------------------------------------------------

fn engine() -> &'static BestPracticeEngine {
    static ENGINE: OnceLock<BestPracticeEngine> = OnceLock::new();
    ENGINE.get_or_init(BestPracticeEngine::new)
}

// ───────────────────────────────────────────────────────────────────────────
//  best_practice
// ───────────────────────────────────────────────────────────────────────────

/// Run best-practice audits (architecture, code quality, skills).
pub struct BestPractice;

impl Tool for BestPractice {
    fn name(&self) -> &'static str {
        "best_practice"
    }

    fn description(&self) -> &'static str {
        "Run architecture audit, code-quality scan, embedded-skills lookup, \
         or commit-message validation. Sub-actions: 'audit_all', 'audit_layering', \
         'scan_quality', 'list_skills', 'get_skill', 'validate_commit', 'suggest_commit'."
    }

    fn parameters(&self) -> Value {
        json!({
            "type": "object",
            "properties": {
                "action": {
                    "type": "string",
                    "enum": [
                        "audit_all",
                        "audit_layering",
                        "scan_quality",
                        "list_skills",
                        "get_skill",
                        "validate_commit",
                        "suggest_commit"
                    ],
                    "description": "Which action to perform"
                },
                "workspace": {
                    "type": "string",
                    "description": "Path to workspace root (required for audit/scan actions)"
                },
                "skill_name": {
                    "type": "string",
                    "description": "Skill name to retrieve (required for 'get_skill')"
                },
                "commit_message": {
                    "type": "string",
                    "description": "Commit message to validate (required for 'validate_commit')"
                },
                "commit_type": {
                    "type": "string",
                    "description": "Commit type for template suggestion (e.g. 'feat', 'fix')"
                },
                "commit_scope": {
                    "type": "string",
                    "description": "Optional scope for template suggestion"
                }
            },
            "required": ["action"]
        })
    }

    #[instrument(skip(self, _ctx, args))]
    fn run(&self, _ctx: &ToolCtx, args: &Value) -> Result<String> {
        let action = arg_str(args, "action")?;
        let eng = engine();

        match action.as_str() {
            "list_skills" => {
                let skills = eng.list_skills();
                let summaries = eng.skill_summaries();
                let mut out = String::from("=== Embedded Best-Practice Skills ===\n\n");
                for (name, desc) in &summaries {
                    out.push_str(&format!("  {name:<40} {desc}\n"));
                }
                if skills.is_empty() {
                    out.push_str("  (no skills embedded)\n");
                }
                Ok(out)
            }

            "get_skill" => {
                let name = arg_str(args, "skill_name")?;
                match eng.get_skill(&name) {
                    Some(content) => Ok(content.to_string()),
                    None => {
                        let available = eng.list_skills();
                        bail!(
                            "Skill '{name}' not found. Available skills: {}",
                            available.join(", ")
                        )
                    }
                }
            }

            "validate_commit" => {
                let msg = arg_str(args, "commit_message")?;
                match eng.validate_commit(&msg) {
                    Ok(()) => Ok("✅ Commit message is valid.".to_string()),
                    Err(errors) => {
                        let mut out = String::from("❌ Commit message validation failed:\n");
                        for err in &errors {
                            out.push_str(&format!("  - {err}\n"));
                        }
                        // Suggest a template.
                        if let Some(parsed) = eng.parse_commit(&msg) {
                            let tpl = eng.suggest_commit_template(&parsed.type_, parsed.scope.as_deref());
                            out.push_str(&format!("\nTemplate: {tpl}\n"));
                        }
                        Ok(out)
                    }
                }
            }

            "suggest_commit" => {
                let type_ = arg_str(args, "commit_type")?;
                let scope = args.get("commit_scope").and_then(|v| v.as_str());
                let tpl = eng.suggest_commit_template(&type_, scope);
                Ok(format!(
                    "Suggested commit template:\n\n  {tpl}\n\n\
                     Valid types: feat, fix, chore, docs, refactor, test, style, perf, ci, build, revert"
                ))
            }

            "audit_layering" | "audit_all" | "scan_quality" => {
                let workspace = match args.get("workspace").and_then(|v| v.as_str()) {
                    Some(w) => w.to_string(),
                    None => bail!("'workspace' argument is required for '{action}'"),
                };
                let ws_path = std::path::Path::new(&workspace);

                // Use the host's dirs data dir when workspace is the default data directory.
                let report = match action.as_str() {
                    "audit_layering" => {
                        let r = eng.audit_layering(ws_path)?;
                        let mut out = format!(
                            "=== Architecture Layering Audit ===\n\
                             Files scanned: {}\n",
                            r.files_scanned
                        );
                        if r.violations.is_empty() {
                            out.push_str("  ✅ No layering violations found.\n");
                        } else {
                            out.push_str(&format!("  Errors: {}\n", r.error_count()));
                            out.push_str(&format!("  Warnings: {}\n", r.warning_count()));
                            for v in &r.violations {
                                out.push_str(&format!(
                                    "  [{}] {}:{} — {}\n",
                                    v.severity, v.file, v.line, v.message
                                ));
                            }
                        }
                        out
                    }
                    "scan_quality" => {
                        let r = eng.scan_quality(ws_path)?;
                        let mut out = format!(
                            "=== Code Quality Scan ===\n\
                             Files scanned: {}\n",
                            r.files_scanned
                        );
                        if r.findings.is_empty() {
                            out.push_str("  ✅ No code-quality issues found.\n");
                        } else {
                            let by_rule = r.count_by_rule();
                            out.push_str("  By rule:\n");
                            for (rule, count) in &by_rule {
                                out.push_str(&format!("    {rule}: {count}\n"));
                            }
                            for f in r.findings.iter().take(15) {
                                out.push_str(&format!(
                                    "  [{}] {}:{} — {}: {}\n",
                                    f.severity, f.file, f.line, f.rule, f.message
                                ));
                            }
                            if r.findings.len() > 15 {
                                out.push_str(&format!(
                                    "  ... and {} more findings.\n",
                                    r.findings.len() - 15
                                ));
                            }
                        }
                        out
                    }
                    _ => {
                        let combined = eng.audit_all(ws_path)?;
                        combined.format()
                    }
                };
                Ok(report)
            }

            other => bail!("Unknown action '{other}'"),
        }
    }
}

// ───────────────────────────────────────────────────────────────────────────
//  commit_convention
// ───────────────────────────────────────────────────────────────────────────

/// Dedicated commit-message validation tool.
pub struct CommitConvention;

impl Tool for CommitConvention {
    fn name(&self) -> &'static str {
        "commit_convention"
    }

    fn description(&self) -> &'static str {
        "Validate a git commit message against Conventional Commits format (Bahasa Indonesia). \
         Checks type, scope, description casing, length, and punctuation."
    }

    fn parameters(&self) -> Value {
        json!({
            "type": "object",
            "properties": {
                "message": {
                    "type": "string",
                    "description": "The full commit message to validate"
                }
            },
            "required": ["message"]
        })
    }

    #[instrument(skip(self, _ctx, args))]
    fn run(&self, _ctx: &ToolCtx, args: &Value) -> Result<String> {
        let msg = arg_str(args, "message")?;
        let eng = engine();

        // Try to parse for additional context.
        let info = eng.parse_commit(&msg);

        match eng.validate_commit(&msg) {
            Ok(()) => {
                let mut out = String::from("✅ Valid Conventional Commit.\n");
                if let Some(i) = info {
                    out.push_str(&format!("  Type:       {}\n", i.type_));
                    if let Some(ref s) = i.scope {
                        out.push_str(&format!("  Scope:      {s}\n"));
                    }
                    out.push_str(&format!("  Breaking:   {}\n", i.breaking));
                    out.push_str(&format!("  Description: {}\n", i.description));
                }
                Ok(out)
            }
            Err(errors) => {
                let mut out = String::from("❌ Invalid commit message:\n");
                for err in &errors {
                    out.push_str(&format!("  - {err}\n"));
                }
                // Provide a template suggestion.
                out.push_str("\nExpected format:\n");
                out.push_str("  feat(scope): <imperative description>\n");
                out.push_str("  fix(scope):  <imperative description>\n");
                out.push_str("  chore:       <imperative description>\n");
                out.push_str("  docs:        <imperative description>\n");
                Ok(out)
            }
        }
    }
}

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

    fn test_ctx() -> ToolCtx {
        // Minimal context for unit tests
        let temp = std::env::temp_dir().join("zesdex-bptest");
        let _ = std::fs::create_dir_all(&temp);
        ToolCtx::builder()
            .workspaces(vec![temp.clone()])
            .session_dir(temp.clone())
            .build()
    }

    #[test]
    fn best_practice_list_skills() {
        let tool = BestPractice;
        let args = json!({"action": "list_skills"});
        let result = tool.run(&test_ctx(), &args).unwrap();
        assert!(result.contains("clean-code"), "should list clean-code: {result}");
        assert!(result.contains("commit-convention"), "should list commit-convention: {result}");
    }

    #[test]
    fn best_practice_get_skill() {
        let tool = BestPractice;
        let args = json!({"action": "get_skill", "skill_name": "clean-code"});
        let result = tool.run(&test_ctx(), &args).unwrap();
        assert!(result.contains("Clean Code"), "should contain skill content: {result}");
    }

    #[test]
    fn commit_convention_valid() {
        let tool = CommitConvention;
        let args = json!({"message": "feat(tool): add best practice audit"});
        let result = tool.run(&test_ctx(), &args).unwrap();
        assert!(result.contains("✅"), "valid commit should succeed: {result}");
    }

    #[test]
    fn commit_convention_invalid() {
        let tool = CommitConvention;
        let args = json!({"message": "Add new feature"});
        let result = tool.run(&test_ctx(), &args).unwrap();
        assert!(result.contains("❌"), "invalid commit should fail: {result}");
    }
}