specsync 4.1.0

use crate::config::{default_schema_pattern, discover_manifest_modules};
use crate::exports::{get_exported_symbols_full, has_extension, is_test_file};
use crate::parser::{
    find_stub_sections, get_missing_sections, get_spec_symbols, parse_frontmatter,
};
use crate::schema::{self, SchemaTable};
use crate::types::{
    CoverageReport, CustomRuleType, Frontmatter, RuleSeverity, SpecSyncConfig, ValidationResult,
};
use regex::Regex;
use std::collections::{HashMap, HashSet};
use std::fs;
use std::path::{Path, PathBuf};
use std::sync::LazyLock;
use walkdir::WalkDir;

static CONSUMED_BY_RE: LazyLock<Regex> =
    LazyLock::new(|| Regex::new(r"(?s)### Consumed By\s*\n(.*?)(?:\n## |\n### |$)").unwrap());
static FILE_REF_RE: LazyLock<Regex> =
    LazyLock::new(|| Regex::new(r"\|\s*`([^`]+\.\w+)`\s*\|").unwrap());
static NUMBERED_RE: LazyLock<Regex> = LazyLock::new(|| Regex::new(r"(?m)^\d+\.\s+\S").unwrap());

/// Check if a dependency reference is a cross-project reference.
/// Cross-project refs use the format `owner/repo@module` (e.g. `corvid-labs/algochat@auth`).
pub fn is_cross_project_ref(dep: &str) -> bool {
    dep.contains('/') && dep.contains('@')
}

/// Parse a cross-project reference into (owner/repo, module).
/// Returns None if not a valid cross-project ref.
pub fn parse_cross_project_ref(dep: &str) -> Option<(&str, &str)> {
    if !is_cross_project_ref(dep) {
        return None;
    }
    let at_pos = dep.find('@')?;
    let repo = &dep[..at_pos];
    let module = &dep[at_pos + 1..];
    if repo.is_empty() || module.is_empty() {
        return None;
    }
    Some((repo, module))
}

// ─── Schema Table Discovery ──────────────────────────────────────────────

/// Extract table names from SQL schema files.
pub fn get_schema_table_names(root: &Path, config: &SpecSyncConfig) -> HashSet<String> {
    let mut tables = HashSet::new();
    let schema_dir = match &config.schema_dir {
        Some(d) => root.join(d),
        None => return tables,
    };

    if !schema_dir.exists() {
        return tables;
    }

    let pattern_str = config
        .schema_pattern
        .as_deref()
        .unwrap_or_else(|| default_schema_pattern());

    let re = match Regex::new(pattern_str) {
        Ok(r) => r,
        Err(_) => return tables,
    };

    if let Ok(entries) = fs::read_dir(&schema_dir) {
        for entry in entries.flatten() {
            let path = entry.path();
            let ext = path.extension().and_then(|e| e.to_str()).unwrap_or("");
            if ext != "ts" && ext != "sql" {
                continue;
            }
            if let Ok(content) = fs::read_to_string(&path) {
                for caps in re.captures_iter(&content) {
                    if let Some(name) = caps.get(1) {
                        tables.insert(name.as_str().to_string());
                    }
                }
            }
        }
    }

    tables
}

// ─── File Discovery ──────────────────────────────────────────────────────

/// Find all *.spec.md files in a directory recursively.
pub fn find_spec_files(dir: &Path) -> Vec<PathBuf> {
    let mut results = Vec::new();
    if !dir.exists() {
        return results;
    }

    for entry in WalkDir::new(dir).into_iter().filter_map(|e| e.ok()) {
        let path = entry.path();
        if path.is_file()
            && let Some(name) = path.file_name().and_then(|n| n.to_str())
            && name.ends_with(".spec.md")
        {
            results.push(path.to_path_buf());
        }
    }

    results.sort();
    results
}

/// Find source files in a directory, respecting exclusions.
fn find_source_files(
    dir: &Path,
    exclude_dirs: &HashSet<String>,
    config: &SpecSyncConfig,
) -> Vec<PathBuf> {
    let mut results = Vec::new();
    if !dir.exists() {
        return results;
    }

    for entry in WalkDir::new(dir)
        .into_iter()
        .filter_entry(|e| {
            if e.file_type().is_dir() {
                let name = e.file_name().to_str().unwrap_or("");
                !exclude_dirs.contains(name)
            } else {
                true
            }
        })
        .filter_map(|e| e.ok())
    {
        let path = entry.path();
        if path.is_file() && has_extension(path, &config.source_extensions) && !is_test_file(path) {
            results.push(path.to_path_buf());
        }
    }

    results
}

// ─── Single Spec Validation ──────────────────────────────────────────────

/// Validate a single spec file against source code.
pub fn validate_spec(
    spec_path: &Path,
    root: &Path,
    schema_tables: &HashSet<String>,
    schema_columns: &HashMap<String, SchemaTable>,
    config: &SpecSyncConfig,
) -> ValidationResult {
    let rel_path = spec_path
        .strip_prefix(root)
        .unwrap_or(spec_path)
        .to_string_lossy()
        .to_string();

    let mut result = ValidationResult::new(rel_path);

    let content = match fs::read_to_string(spec_path) {
        Ok(c) => c.replace("\r\n", "\n"),
        Err(e) => {
            result.errors.push(format!("Cannot read spec: {e}"));
            return result;
        }
    };

    let parsed = match parse_frontmatter(&content) {
        Some(p) => p,
        None => {
            result.errors.push(
                "Missing or malformed YAML frontmatter (expected --- delimiters)".to_string(),
            );
            return result;
        }
    };

    let fm = &parsed.frontmatter;
    let body = &parsed.body;

    // Archived specs: skip all validation with zero diagnostics.
    // Must be invisible to --strict mode.
    if fm.parsed_status() == Some(crate::types::SpecStatus::Archived) {
        return result;
    }

    // ─── Level 1: Structural ──────────────────────────────────────────

    if fm.module.is_none() {
        result
            .errors
            .push("Frontmatter missing required field: module".to_string());
        result
            .fixes
            .push("Add `module: your-module-name` to the YAML frontmatter block".to_string());
    }
    if fm.version.is_none() {
        result
            .errors
            .push("Frontmatter missing required field: version".to_string());
        result
            .fixes
            .push("Add `version: 1` to the YAML frontmatter block".to_string());
    }
    if fm.status.is_none() {
        result
            .errors
            .push("Frontmatter missing required field: status".to_string());
        result.fixes.push(
            "Add `status: active` (or draft/review/stable/deprecated/archived) to the frontmatter"
                .to_string(),
        );
    } else if let Some(status_str) = &fm.status {
        if fm.parsed_status().is_none() {
            result.warnings.push(format!(
                "Unknown status '{}' — expected one of: draft, review, active, stable, deprecated, archived",
                status_str
            ));
        }
    }

    // Status lifecycle warnings
    let spec_status = fm.parsed_status();
    if spec_status == Some(crate::types::SpecStatus::Deprecated) {
        result
            .warnings
            .push("Spec is deprecated — consider archiving with `specsync lifecycle promote <spec>` or `specsync lifecycle set <spec> archived`".to_string());
    }

    // Validate agent_policy if present
    if let Some(policy) = &fm.agent_policy {
        match policy.as_str() {
            "read-only" | "suggest-only" | "full-access" => {}
            _ => {
                result.warnings.push(format!(
                    "Unknown agent_policy '{}' — expected: read-only, suggest-only, or full-access",
                    policy
                ));
            }
        }
    }
    if fm.files.is_empty() {
        result.errors.push(
            "Frontmatter missing required field: files (must be a non-empty list)".to_string(),
        );
        result.fixes.push(
            "Add a `files:` list with relative paths to source files this spec covers".to_string(),
        );
    }

    // Check files exist
    for file in &fm.files {
        let full_path = root.join(file);
        if !full_path.exists() {
            result.errors.push(format!("Source file not found: {file}"));
            // Suggest similar files
            if let Some(suggestion) = suggest_similar_file(root, file) {
                result.fixes.push(format!(
                    "Did you mean `{suggestion}`? Update the path in frontmatter"
                ));
            } else {
                result.fixes.push(format!(
                    "Remove `{file}` from files list or create the source file"
                ));
            }
        }
    }

    // Check db_tables exist in schema
    for table in &fm.db_tables {
        if !schema_tables.is_empty() && !schema_tables.contains(table) {
            result
                .errors
                .push(format!("DB table not found in schema: {table}"));
            result.fixes.push(format!(
                "Remove `{table}` from db_tables or add a CREATE TABLE migration"
            ));
        }
    }

    // ─── Level 1.5: Schema Columns ──────────────────────────────────────
    if !schema_columns.is_empty() {
        let spec_schema = schema::parse_spec_schema(body);
        for table_name in &fm.db_tables {
            if let Some(actual_table) = schema_columns.get(table_name)
                && let Some(spec_cols) = spec_schema.get(table_name)
            {
                let actual_names: HashSet<&str> = actual_table
                    .columns
                    .iter()
                    .map(|c| c.name.as_str())
                    .collect();
                let spec_names: HashSet<&str> = spec_cols.iter().map(|c| c.name.as_str()).collect();

                // Spec documents a column that doesn't exist = ERROR
                for sc in spec_cols {
                    if !actual_names.contains(sc.name.as_str()) {
                        result.errors.push(format!(
                            "Schema column `{}.{}` documented in spec but not found in migrations",
                            table_name, sc.name
                        ));
                        result.fixes.push(format!(
                            "Remove `{}` from the ### Schema section or add it via ALTER TABLE",
                            sc.name
                        ));
                    }
                }

                // Column exists in schema but not in spec = WARNING
                for ac in &actual_table.columns {
                    if !spec_names.contains(ac.name.as_str()) {
                        result.warnings.push(format!(
                            "Schema column `{}.{}` exists in migrations but not documented in spec",
                            table_name, ac.name
                        ));
                    }
                }

                // Type mismatch = WARNING
                for sc in spec_cols {
                    if let Some(ac) = actual_table.columns.iter().find(|c| c.name == sc.name) {
                        // Normalise both to uppercase for comparison
                        let spec_type = sc.col_type.to_uppercase();
                        let actual_type = ac.col_type.to_uppercase();
                        if spec_type != actual_type {
                            result.warnings.push(format!(
                                "Schema column `{}.{}` type mismatch: spec says {} but migrations say {}",
                                table_name, sc.name, spec_type, actual_type
                            ));
                        }
                    }
                }
            }
            // If spec has db_tables but no ### Schema section, that's fine —
            // column-level docs are optional. Only validate when present.
        }
    }

    // Required markdown sections
    // - draft: structure only — skip all required section checks
    // - review: structure + sections, but skip "Public API"
    // - active/stable/deprecated: all sections required
    let is_draft = spec_status == Some(crate::types::SpecStatus::Draft);
    let is_review = spec_status == Some(crate::types::SpecStatus::Review);

    if !is_draft {
        let missing = get_missing_sections(body, &config.required_sections);
        for section in &missing {
            if is_review && section == "Public API" {
                continue; // review specs can skip Public API
            }
            result
                .errors
                .push(format!("Missing required section: ## {section}"));
            result
                .fixes
                .push(format!("Add `## {section}` heading to the spec body"));
        }
    }

    // ─── Level 1.7: Stub/Placeholder Detection ──────────────────────
    let stub_sections = find_stub_sections(body, &config.required_sections);
    if !stub_sections.is_empty() {
        for section in &stub_sections {
            result.warnings.push(format!(
                "Section ## {section} contains only stub/placeholder text (TBD, N/A, TODO, etc.)"
            ));
            result.fixes.push(format!(
                "Replace placeholder content in ## {section} with real documentation"
            ));
        }
    }

    // ─── Level 2: API Surface ─────────────────────────────────────────
    // Draft and review specs skip API surface validation — exports may not exist yet.
    let skip_api = matches!(
        spec_status,
        Some(crate::types::SpecStatus::Draft) | Some(crate::types::SpecStatus::Review)
    );

    if !fm.files.is_empty() && !skip_api {
        // Track exports with their source file for attribution
        let mut exports_by_file: Vec<(String, String)> = Vec::new(); // (symbol, file)
        let mut all_exports: Vec<String> = Vec::new();
        for file in &fm.files {
            let full_path = root.join(file);
            let exports =
                get_exported_symbols_full(&full_path, config.export_level, config.parse_mode);
            for sym in &exports {
                exports_by_file.push((sym.clone(), file.clone()));
            }
            all_exports.extend(exports);
        }

        // Deduplicate (keep first occurrence for file attribution)
        let mut seen = HashSet::new();
        all_exports.retain(|s| seen.insert(s.clone()));

        let spec_symbols = get_spec_symbols(body);
        let spec_set: HashSet<&str> = spec_symbols.iter().map(|s| s.as_str()).collect();
        let export_set: HashSet<&str> = all_exports.iter().map(|s| s.as_str()).collect();

        // Spec documents something that doesn't exist = ERROR
        for sym in &spec_symbols {
            if !export_set.contains(sym.as_str()) {
                result.errors.push(format!(
                    "Spec documents '{sym}' but no matching export found in source"
                ));
            }
        }

        // Code exports something not in spec = WARNING (with source file attribution)
        for sym in &all_exports {
            if !spec_set.contains(sym.as_str()) {
                // Find the source file for this export
                let source_file = exports_by_file
                    .iter()
                    .find(|(s, _)| s == sym)
                    .map(|(_, f)| f.as_str());
                match source_file {
                    Some(file) => {
                        result
                            .warnings
                            .push(format!("Undocumented export '{sym}' from {file}"));
                    }
                    None => {
                        result
                            .warnings
                            .push(format!("Export '{sym}' not in spec (undocumented)"));
                    }
                }
            }
        }

        let documented = spec_symbols
            .iter()
            .filter(|s| export_set.contains(s.as_str()))
            .count();

        if !all_exports.is_empty() {
            let summary = format!("{documented}/{} exports documented", all_exports.len());
            if documented < all_exports.len() {
                result.warnings.insert(0, summary);
            } else {
                result.export_summary = Some(summary);
            }
        }
    }

    // ─── Level 3: Dependencies ────────────────────────────────────────

    if !fm.depends_on.is_empty() {
        for dep in &fm.depends_on {
            if is_cross_project_ref(dep) {
                // Cross-project refs (e.g. "owner/repo@module") are validated
                // by `specsync resolve`, not during local checks.
                continue;
            }
            let full_path = root.join(dep);
            if !full_path.exists() {
                result
                    .errors
                    .push(format!("Dependency spec not found: {dep}"));
            }
        }
    }

    // Check Consumed By section references
    if let Some(caps) = CONSUMED_BY_RE.captures(body) {
        let section = caps.get(1).unwrap().as_str();
        for caps in FILE_REF_RE.captures_iter(section) {
            if let Some(file_ref) = caps.get(1) {
                let file_path = root.join(file_ref.as_str());
                if !file_path.exists() {
                    result.warnings.push(format!(
                        "Consumed By references missing file: {}",
                        file_ref.as_str()
                    ));
                }
            }
        }
    }

    // ─── Level 4: Requirements Companion File ─────────────────────────
    // spec-sync expects requirements in a separate companion file (requirements.md),
    // not inline in the spec body. Warn if requirements appear inline.
    // Drafts and review specs skip this check.
    if !is_draft && spec_status != Some(crate::types::SpecStatus::Review) {
        let has_inline_requirements = {
            let lower = body.to_ascii_lowercase();
            lower.contains("## requirements") || lower.contains("## acceptance criteria")
        };
        if has_inline_requirements {
            result.warnings.push(
                "Inline requirements detected — specs are technical contracts; user stories and acceptance criteria belong in a companion requirements.md file".to_string()
            );
            result.fixes.push(
                "Run `specsync add-spec <name>` to scaffold requirements.md, then move ## Requirements / ## Acceptance Criteria content there".to_string()
            );
        }

        // Check that the companion requirements.md exists for non-draft specs
        if let Some(parent) = spec_path.parent() {
            let req_path = parent.join("requirements.md");
            if !req_path.exists() {
                result.warnings.push(
                    "Missing companion requirements.md — run `specsync add-spec <name>` or `specsync generate` to scaffold one".to_string()
                );
            }
        }
    }

    // ─── Custom Validation Rules ─────────────────────────────────────
    apply_custom_rules(spec_path, body, fm, config, &mut result);

    result
}

/// Apply project-specific custom validation rules from config.
fn apply_custom_rules(
    spec_path: &Path,
    body: &str,
    fm: &Frontmatter,
    config: &SpecSyncConfig,
    result: &mut ValidationResult,
) {
    let rules = &config.rules;

    // max_spec_size_kb: warn if spec file is too large
    if let Some(max_kb) = rules.max_spec_size_kb {
        if let Ok(meta) = fs::metadata(spec_path) {
            let size_kb = meta.len() as usize / 1024;
            if size_kb > max_kb {
                result.warnings.push(format!(
                    "Spec file is {size_kb} KB — exceeds limit of {max_kb} KB"
                ));
            }
        }
    }

    // max_changelog_entries: warn if Change Log has too many rows
    if let Some(max_entries) = rules.max_changelog_entries {
        let count = count_changelog_entries(body);
        if count > max_entries {
            result.warnings.push(format!(
                "Change Log has {count} entries — exceeds limit of {max_entries} (run `specsync compact`)"
            ));
        }
    }

    // require_behavioral_examples: require at least one ### Scenario
    if rules.require_behavioral_examples == Some(true) {
        let scenario_count = body.matches("### Scenario").count();
        if scenario_count == 0 {
            result.errors.push(
                "No behavioral examples found (rule: require_behavioral_examples)".to_string(),
            );
            result.fixes.push(
                "Add at least one `### Scenario:` under `## Behavioral Examples`".to_string(),
            );
        }
    }

    // min_invariants: require a minimum number of numbered invariants
    if let Some(min) = rules.min_invariants {
        let count = count_invariants(body);
        if count < min {
            result.warnings.push(format!(
                "Only {count} invariant(s) found — minimum is {min}"
            ));
        }
    }

    // require_depends_on: require non-empty depends_on in frontmatter
    if rules.require_depends_on == Some(true) && fm.depends_on.is_empty() {
        result
            .warnings
            .push("No consumed dependencies documented (rule: require_depends_on)".to_string());
    }

    // ─── Declarative Custom Rules ────────────────────────────────────
    for rule in &config.custom_rules {
        if !custom_rule_applies(rule, fm) {
            continue;
        }
        if let Some(msg) = evaluate_custom_rule(rule, body) {
            let tagged = format!("{msg} (rule: {})", rule.name);
            match rule.severity {
                RuleSeverity::Error => result.errors.push(tagged),
                RuleSeverity::Warning => result.warnings.push(tagged),
                RuleSeverity::Info => result.warnings.push(format!("[info] {tagged}")),
            }
        }
    }
}

/// Check whether a custom rule applies to the given spec based on its filter.
fn custom_rule_applies(rule: &crate::types::CustomRule, fm: &Frontmatter) -> bool {
    let Some(ref filter) = rule.applies_to else {
        return true;
    };

    if let Some(ref status) = filter.status {
        let spec_status = fm.status.as_deref().unwrap_or("");
        if !spec_status.eq_ignore_ascii_case(status) {
            return false;
        }
    }

    if let Some(ref module_pattern) = filter.module {
        let spec_module = fm.module.as_deref().unwrap_or("");
        if let Ok(re) = Regex::new(module_pattern) {
            if !re.is_match(spec_module) {
                return false;
            }
        }
    }

    true
}

/// Evaluate a single custom rule against the spec body.
/// Returns `Some(message)` if the rule is violated, `None` if it passes.
fn evaluate_custom_rule(rule: &crate::types::CustomRule, body: &str) -> Option<String> {
    match rule.rule_type {
        CustomRuleType::RequireSection => {
            let section = rule.section.as_deref()?;
            let header = format!("## {section}");
            if !body.contains(&header) {
                let msg = rule
                    .message
                    .clone()
                    .unwrap_or_else(|| format!("Missing required section: ## {section}"));
                return Some(msg);
            }
            None
        }
        CustomRuleType::MinWordCount => {
            let section = rule.section.as_deref()?;
            let min = rule.min_words.unwrap_or(1);
            let header = format!("## {section}");
            let section_start = body.find(&header)?;
            let after_header = &body[section_start + header.len()..];
            // Bound section to next ## heading
            let section_end = after_header.find("\n## ").unwrap_or(after_header.len());
            let section_body = &after_header[..section_end];
            let word_count = section_body.split_whitespace().count();
            if word_count < min {
                let msg = rule.message.clone().unwrap_or_else(|| {
                    format!("Section ## {section} has {word_count} words — minimum is {min}")
                });
                return Some(msg);
            }
            None
        }
        CustomRuleType::RequirePattern => {
            let pattern = rule.pattern.as_deref()?;
            let re = Regex::new(pattern).ok()?;
            if !re.is_match(body) {
                let msg = rule
                    .message
                    .clone()
                    .unwrap_or_else(|| format!("Required pattern not found: {pattern}"));
                return Some(msg);
            }
            None
        }
        CustomRuleType::ForbidPattern => {
            let pattern = rule.pattern.as_deref()?;
            let re = Regex::new(pattern).ok()?;
            if re.is_match(body) {
                let msg = rule
                    .message
                    .clone()
                    .unwrap_or_else(|| format!("Forbidden pattern found: {pattern}"));
                return Some(msg);
            }
            None
        }
    }
}

/// Count data rows in the Change Log table (excluding header and separator).
fn count_changelog_entries(body: &str) -> usize {
    let changelog_start = match body.find("## Change Log") {
        Some(pos) => pos,
        None => return 0,
    };
    let section = &body[changelog_start..];
    // Find next ## heading to bound the section
    let section_end = section[1..]
        .find("\n## ")
        .map(|p| p + 1)
        .unwrap_or(section.len());
    let section = &section[..section_end];

    // Count data rows: skip the first two table lines (header + separator)
    let mut table_line_count = 0usize;
    section
        .lines()
        .filter(|line| {
            let trimmed = line.trim();
            if !trimmed.starts_with('|') {
                return false;
            }
            table_line_count += 1;
            table_line_count > 2
        })
        .count()
}

/// Count numbered invariants in the Invariants section.
fn count_invariants(body: &str) -> usize {
    let inv_start = match body.find("## Invariants") {
        Some(pos) => pos,
        None => return 0,
    };
    let section = &body[inv_start..];
    let section_end = section[1..]
        .find("\n## ")
        .map(|p| p + 1)
        .unwrap_or(section.len());
    let section = &section[..section_end];

    NUMBERED_RE.find_iter(section).count()
}

/// Suggest a similar file path when a referenced file doesn't exist.
fn suggest_similar_file(root: &Path, missing_file: &str) -> Option<String> {
    let missing_name = Path::new(missing_file).file_name()?.to_str()?;

    let parent = Path::new(missing_file).parent()?;
    let search_dir = root.join(parent);
    if !search_dir.exists() {
        return None;
    }

    let entries = std::fs::read_dir(&search_dir).ok()?;
    let mut best: Option<(String, usize)> = None;

    for entry in entries.flatten() {
        let name = entry.file_name().to_string_lossy().to_string();
        if !entry.path().is_file() {
            continue;
        }
        let dist = levenshtein(missing_name, &name);
        if dist <= 3 && (best.is_none() || dist < best.as_ref().unwrap().1) {
            let suggestion = parent.join(&name).to_string_lossy().replace('\\', "/");
            best = Some((suggestion, dist));
        }
    }

    best.map(|(s, _)| s)
}

/// Simple Levenshtein distance for file name suggestions.
fn levenshtein(a: &str, b: &str) -> usize {
    let a: Vec<char> = a.chars().collect();
    let b: Vec<char> = b.chars().collect();
    let mut dp = vec![vec![0usize; b.len() + 1]; a.len() + 1];

    for (i, row) in dp.iter_mut().enumerate().take(a.len() + 1) {
        row[0] = i;
    }
    for (j, val) in dp[0].iter_mut().enumerate().take(b.len() + 1) {
        *val = j;
    }
    for i in 1..=a.len() {
        for j in 1..=b.len() {
            let cost = if a[i - 1] == b[j - 1] { 0 } else { 1 };
            dp[i][j] = (dp[i - 1][j] + 1)
                .min(dp[i][j - 1] + 1)
                .min(dp[i - 1][j - 1] + cost);
        }
    }
    dp[a.len()][b.len()]
}

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

    #[test]
    fn test_is_cross_project_ref() {
        assert!(is_cross_project_ref("corvid-labs/algochat@auth"));
        assert!(is_cross_project_ref("owner/repo@module"));
        assert!(!is_cross_project_ref("specs/auth/auth.spec.md"));
        assert!(!is_cross_project_ref("auth"));
        assert!(!is_cross_project_ref("owner/repo")); // no @
        assert!(!is_cross_project_ref("@module")); // no /
    }

    #[test]
    fn test_parse_cross_project_ref() {
        let (repo, module) = parse_cross_project_ref("corvid-labs/algochat@auth").unwrap();
        assert_eq!(repo, "corvid-labs/algochat");
        assert_eq!(module, "auth");

        assert!(parse_cross_project_ref("not-a-ref").is_none());
        assert!(parse_cross_project_ref("/@").is_none()); // empty parts
    }

    #[test]
    fn test_levenshtein() {
        assert_eq!(levenshtein("kitten", "sitting"), 3);
        assert_eq!(levenshtein("abc", "abc"), 0);
        assert_eq!(levenshtein("", "abc"), 3);
        assert_eq!(levenshtein("abc", ""), 3);
        assert_eq!(levenshtein("config.ts", "confg.ts"), 1);
    }

    #[test]
    fn test_find_spec_files_empty_dir() {
        let tmp = tempfile::tempdir().unwrap();
        let files = find_spec_files(tmp.path());
        assert!(files.is_empty());
    }

    #[test]
    fn test_find_spec_files_nonexistent() {
        let files = find_spec_files(Path::new("/nonexistent/path"));
        assert!(files.is_empty());
    }

    #[test]
    fn test_find_spec_files_with_specs() {
        let tmp = tempfile::tempdir().unwrap();
        let spec_dir = tmp.path().join("auth");
        fs::create_dir_all(&spec_dir).unwrap();
        fs::write(spec_dir.join("auth.spec.md"), "---\nmodule: auth\n---\n").unwrap();
        fs::write(spec_dir.join("not-a-spec.md"), "other").unwrap();

        let files = find_spec_files(tmp.path());
        assert_eq!(files.len(), 1);
        assert!(files[0].ends_with("auth.spec.md"));
    }

    #[test]
    fn test_validate_spec_missing_frontmatter() {
        let tmp = tempfile::tempdir().unwrap();
        let spec = tmp.path().join("bad.spec.md");
        fs::write(&spec, "# No frontmatter\n\nJust text.").unwrap();

        let tables = HashSet::new();
        let schema_cols = HashMap::new();
        let config = SpecSyncConfig::default();
        let result = validate_spec(&spec, tmp.path(), &tables, &schema_cols, &config);
        assert!(!result.errors.is_empty());
        assert!(result.errors[0].contains("frontmatter"));
    }

    #[test]
    fn test_validate_spec_missing_required_fields() {
        let tmp = tempfile::tempdir().unwrap();
        let spec = tmp.path().join("partial.spec.md");
        fs::write(&spec, "---\nmodule: test\n---\n\n## Purpose\nTest\n").unwrap();

        let tables = HashSet::new();
        let schema_cols = HashMap::new();
        let config = SpecSyncConfig::default();
        let result = validate_spec(&spec, tmp.path(), &tables, &schema_cols, &config);
        // Should have errors for missing version, status, files
        assert!(result.errors.iter().any(|e| e.contains("version")));
        assert!(result.errors.iter().any(|e| e.contains("status")));
        assert!(result.errors.iter().any(|e| e.contains("files")));
    }

    #[test]
    fn test_validate_spec_missing_source_file() {
        let tmp = tempfile::tempdir().unwrap();
        let spec = tmp.path().join("missing.spec.md");
        fs::write(
            &spec,
            "---\nmodule: test\nversion: 1\nstatus: active\nfiles:\n  - src/nonexistent.ts\n---\n\n## Purpose\nTest\n## Requirements\n## Public API\n## Invariants\n## Behavioral Examples\n## Error Cases\n## Dependencies\n## Change Log\n",
        )
        .unwrap();

        let tables = HashSet::new();
        let schema_cols = HashMap::new();
        let config = SpecSyncConfig::default();
        let result = validate_spec(&spec, tmp.path(), &tables, &schema_cols, &config);
        assert!(
            result
                .errors
                .iter()
                .any(|e| e.contains("Source file not found"))
        );
    }

    #[test]
    fn test_validate_spec_schema_columns() {
        let tmp = tempfile::tempdir().unwrap();
        let src_dir = tmp.path().join("src");
        fs::create_dir_all(&src_dir).unwrap();
        fs::write(src_dir.join("msg.ts"), "export function send() {}").unwrap();

        let spec = tmp.path().join("msg.spec.md");
        fs::write(
            &spec,
            r#"---
module: msg
version: 1
status: active
files:
  - src/msg.ts
db_tables:
  - messages
---

## Purpose
Messaging

## Requirements

### Schema: messages

| Column | Type | Constraints |
|--------|------|-------------|
| `id` | INTEGER | PRIMARY KEY |
| `content` | TEXT | NOT NULL |
| `ghost_col` | TEXT | NOT NULL |

## Public API

### Exported Functions

| Function | Parameters | Returns | Description |
|----------|-----------|---------|-------------|
| `send` | msg: string | void | Sends |

## Invariants
## Behavioral Examples
## Error Cases
## Dependencies
## Change Log
"#,
        )
        .unwrap();

        let mut table_names = HashSet::new();
        table_names.insert("messages".to_string());

        let mut schema_cols = HashMap::new();
        schema_cols.insert(
            "messages".to_string(),
            SchemaTable {
                columns: vec![
                    crate::schema::SchemaColumn {
                        name: "id".to_string(),
                        col_type: "INTEGER".to_string(),
                        nullable: false,
                        has_default: false,
                        is_primary_key: true,
                    },
                    crate::schema::SchemaColumn {
                        name: "content".to_string(),
                        col_type: "TEXT".to_string(),
                        nullable: false,
                        has_default: false,
                        is_primary_key: false,
                    },
                    crate::schema::SchemaColumn {
                        name: "created_at".to_string(),
                        col_type: "TEXT".to_string(),
                        nullable: false,
                        has_default: true,
                        is_primary_key: false,
                    },
                ],
            },
        );

        let config = SpecSyncConfig::default();
        let result = validate_spec(&spec, tmp.path(), &table_names, &schema_cols, &config);

        // ghost_col is in spec but not in schema → ERROR
        assert!(result.errors.iter().any(|e| e.contains("ghost_col")));
        // created_at is in schema but not in spec → WARNING
        assert!(result.warnings.iter().any(|w| w.contains("created_at")));
    }

    #[test]
    fn test_validate_spec_schema_type_mismatch() {
        let tmp = tempfile::tempdir().unwrap();
        let src_dir = tmp.path().join("src");
        fs::create_dir_all(&src_dir).unwrap();
        fs::write(src_dir.join("t.ts"), "export function f() {}").unwrap();

        let spec = tmp.path().join("t.spec.md");
        fs::write(
            &spec,
            r#"---
module: t
version: 1
status: active
files:
  - src/t.ts
db_tables:
  - items
---

## Purpose
Test

## Requirements

### Schema: items

| Column | Type | Constraints |
|--------|------|-------------|
| `id` | INTEGER | PRIMARY KEY |
| `price` | TEXT | |

## Public API

### Exported Functions

| Function | Parameters | Returns | Description |
|----------|-----------|---------|-------------|
| `f` | | void | Does stuff |

## Invariants
## Behavioral Examples
## Error Cases
## Dependencies
## Change Log
"#,
        )
        .unwrap();

        let mut table_names = HashSet::new();
        table_names.insert("items".to_string());

        let mut schema_cols = HashMap::new();
        schema_cols.insert(
            "items".to_string(),
            SchemaTable {
                columns: vec![
                    crate::schema::SchemaColumn {
                        name: "id".to_string(),
                        col_type: "INTEGER".to_string(),
                        nullable: false,
                        has_default: false,
                        is_primary_key: true,
                    },
                    crate::schema::SchemaColumn {
                        name: "price".to_string(),
                        col_type: "REAL".to_string(),
                        nullable: true,
                        has_default: false,
                        is_primary_key: false,
                    },
                ],
            },
        );

        let config = SpecSyncConfig::default();
        let result = validate_spec(&spec, tmp.path(), &table_names, &schema_cols, &config);

        // price type mismatch: spec says TEXT, schema says REAL → WARNING
        assert!(
            result
                .warnings
                .iter()
                .any(|w| w.contains("type mismatch") && w.contains("price"))
        );
    }
}

// ─── Coverage ────────────────────────────────────────────────────────────

fn collect_specced_files(spec_files: &[PathBuf]) -> HashSet<String> {
    let mut specced = HashSet::new();
    for spec_file in spec_files {
        if let Ok(content) = fs::read_to_string(spec_file) {
            let content = content.replace("\r\n", "\n");
            if let Some(parsed) = parse_frontmatter(&content) {
                for f in &parsed.frontmatter.files {
                    specced.insert(f.clone());
                }
            }
        }
    }
    specced
}

fn get_module_dirs(dir: &Path, exclude_dirs: &HashSet<String>) -> Vec<String> {
    let mut modules = Vec::new();
    if !dir.exists() {
        return modules;
    }

    if let Ok(entries) = fs::read_dir(dir) {
        for entry in entries.flatten() {
            if let Ok(ft) = entry.file_type()
                && ft.is_dir()
            {
                let name = entry.file_name().to_string_lossy().to_string();
                if !exclude_dirs.contains(&name) {
                    modules.push(name);
                }
            }
        }
    }

    modules.sort();
    modules
}

/// Get spec module directories that actually contain a .spec.md file.
/// Empty directories (e.g. from a failed prior generation) are ignored.
fn get_spec_module_dirs(dir: &Path) -> Vec<String> {
    let mut modules = Vec::new();
    if !dir.exists() {
        return modules;
    }

    if let Ok(entries) = fs::read_dir(dir) {
        for entry in entries.flatten() {
            if let Ok(ft) = entry.file_type()
                && ft.is_dir()
            {
                let subdir = entry.path();
                let has_spec = fs::read_dir(&subdir)
                    .ok()
                    .map(|entries| {
                        entries.flatten().any(|e| {
                            e.path().is_file()
                                && e.file_name()
                                    .to_str()
                                    .map(|n| n.ends_with(".spec.md"))
                                    .unwrap_or(false)
                        })
                    })
                    .unwrap_or(false);
                if has_spec {
                    let name = entry.file_name().to_string_lossy().to_string();
                    modules.push(name);
                }
            }
        }
    }

    modules.sort();
    modules
}

/// Compute file and module coverage.
pub fn compute_coverage(
    root: &Path,
    spec_files: &[PathBuf],
    config: &SpecSyncConfig,
) -> CoverageReport {
    let specced_files = collect_specced_files(spec_files);
    let exclude_dirs: HashSet<String> = config.exclude_dirs.iter().cloned().collect();

    let mut all_source_files: Vec<String> = Vec::new();
    for src_dir in &config.source_dirs {
        let full_dir = root.join(src_dir);
        let files: Vec<String> = find_source_files(&full_dir, &exclude_dirs, config)
            .into_iter()
            .filter_map(|f| {
                let rel = f.strip_prefix(root).ok()?;
                let rel_str = rel.to_string_lossy().replace('\\', "/");
                // Check exclude patterns (simple glob matching)
                for pattern in &config.exclude_patterns {
                    // **/dir/** — matches path containing dir
                    if pattern.starts_with("**/") && pattern.ends_with("/**") {
                        let dir_part = &pattern[3..pattern.len() - 3];
                        if rel_str.contains(dir_part) {
                            return None;
                        }
                    }
                    // **/*.ext or **/filename — matches suffix/filename
                    else if let Some(suffix) = pattern.strip_prefix("**/") {
                        if let Some(ext) = suffix.strip_prefix('*') {
                            // **/*.test.ts -> .test.ts
                            if rel_str.ends_with(ext) {
                                return None;
                            }
                        } else {
                            // **/index.ts -> matches any path ending in /index.ts or equal to index.ts
                            if rel_str.ends_with(&format!("/{suffix}")) || rel_str == *suffix {
                                return None;
                            }
                        }
                    }
                    // Literal contains match as fallback
                    else if rel_str.contains(pattern.as_str()) {
                        return None;
                    }
                }
                Some(rel_str)
            })
            .collect();
        all_source_files.extend(files);
    }

    // Count lines of code per file
    let file_loc: std::collections::HashMap<&str, usize> = all_source_files
        .iter()
        .map(|f| {
            let loc = fs::read_to_string(root.join(f))
                .map(|c| c.lines().count())
                .unwrap_or(0);
            (f.as_str(), loc)
        })
        .collect();

    let total_loc: usize = file_loc.values().sum();
    let specced_loc: usize = all_source_files
        .iter()
        .filter(|f| specced_files.contains(*f))
        .map(|f| file_loc.get(f.as_str()).copied().unwrap_or(0))
        .sum();

    let unspecced_files: Vec<String> = all_source_files
        .iter()
        .filter(|f| !specced_files.contains(*f))
        .cloned()
        .collect();

    let mut unspecced_file_loc: Vec<(String, usize)> = unspecced_files
        .iter()
        .map(|f| (f.clone(), file_loc.get(f.as_str()).copied().unwrap_or(0)))
        .collect();
    unspecced_file_loc.sort_by(|a, b| b.1.cmp(&a.1));

    // Module coverage
    let specs_dir = root.join(&config.specs_dir);
    let spec_modules: HashSet<String> = get_spec_module_dirs(&specs_dir).into_iter().collect();

    let mut unspecced_modules = Vec::new();
    let mut seen_modules: HashSet<String> = HashSet::new();

    // User-defined modules from specsync.json take priority
    if !config.modules.is_empty() {
        for name in config.modules.keys() {
            if !spec_modules.contains(name) && seen_modules.insert(name.clone()) {
                unspecced_modules.push(name.clone());
            }
        }
    }

    // Then: detect modules from manifest files (Package.swift, Cargo.toml, etc.)
    let manifest = discover_manifest_modules(root);
    for name in manifest.modules.keys() {
        if !spec_modules.contains(name) && seen_modules.insert(name.clone()) {
            unspecced_modules.push(name.clone());
        }
    }

    // Detect subdirectory-based modules
    for src_dir in &config.source_dirs {
        let full_dir = root.join(src_dir);
        for module in get_module_dirs(&full_dir, &exclude_dirs) {
            if !spec_modules.contains(&module) && seen_modules.insert(module.clone()) {
                unspecced_modules.push(module);
            }
        }
    }

    // Detect flat source files as modules (e.g. src/config.rs → module "config")
    let skip_stems: HashSet<&str> = ["main", "lib", "mod", "index", "__init__", "app"]
        .into_iter()
        .collect();
    for src_dir in &config.source_dirs {
        let full_dir = root.join(src_dir);
        if let Ok(entries) = fs::read_dir(&full_dir) {
            for entry in entries.flatten() {
                let path = entry.path();
                if !path.is_file()
                    || !has_extension(&path, &config.source_extensions)
                    || is_test_file(&path)
                {
                    continue;
                }
                let stem = match path.file_stem().and_then(|s| s.to_str()) {
                    Some(s) => s.to_string(),
                    None => continue,
                };
                if skip_stems.contains(stem.as_str()) {
                    continue;
                }
                if !spec_modules.contains(&stem) && seen_modules.insert(stem.clone()) {
                    unspecced_modules.push(stem);
                }
            }
        }
    }

    let specced_count = all_source_files.len() - unspecced_files.len();
    let coverage_percent = if all_source_files.is_empty() {
        100
    } else {
        (specced_count * 100) / all_source_files.len()
    };

    let loc_coverage_percent = if total_loc == 0 {
        100
    } else {
        (specced_loc * 100) / total_loc
    };

    CoverageReport {
        total_source_files: all_source_files.len(),
        specced_file_count: specced_count,
        unspecced_files,
        unspecced_modules,
        coverage_percent,
        total_loc,
        specced_loc,
        loc_coverage_percent,
        unspecced_file_loc,
    }
}