index-compat-lab 1.0.0

//! Offline compatibility artifact synthesis and lint helpers.

use std::collections::{BTreeMap, BTreeSet};

use index_capture::validate_capture_bundle;
use serde::{Deserialize, Serialize};
use serde_json::json;

/// Corpus source label.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
pub enum CorpusSource {
    /// Top-100 corpus matrix.
    Top100,
    /// Forum corpus matrix.
    Forum,
}

impl CorpusSource {
    /// Stable source label.
    #[must_use]
    pub const fn as_str(self) -> &'static str {
        match self {
            Self::Top100 => "top100",
            Self::Forum => "forum",
        }
    }
}

/// Ingested compatibility row.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct LabRow {
    /// Row source.
    pub source: CorpusSource,
    /// Domain identifier from matrix.
    pub domain: String,
    /// Family identifier from matrix.
    pub family: String,
    /// Optional intent identifier.
    pub intent: Option<String>,
    /// Current support tier.
    pub current_tier: u8,
    /// Known limit category.
    pub known_limit: String,
}

/// Ingest summary.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct IngestSummary {
    /// Rows parsed from corpus matrices.
    pub rows: Vec<LabRow>,
    /// Validated capture artifact count.
    pub captures_total: usize,
    /// Rows grouped by family.
    pub family_counts: Vec<(String, usize)>,
}

/// Pack-rule suggestion.
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct PackRuleSuggestion {
    /// Host matcher.
    pub host: String,
    /// Path-prefix matcher.
    pub path_prefix: String,
}

/// Pack lint report.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct PackLintReport {
    /// Collected errors.
    pub errors: Vec<String>,
    /// Collected warnings.
    pub warnings: Vec<String>,
}

impl PackLintReport {
    /// Returns true if lint has no errors.
    #[must_use]
    pub fn passed(&self) -> bool {
        self.errors.is_empty()
    }
}

/// Deterministic synthesis quality report.
#[derive(Debug, Clone, PartialEq)]
pub struct SynthesisQuality {
    /// Family evaluated.
    pub family: String,
    /// Rows eligible for deterministic pack coverage scoring.
    pub eligible_rows: usize,
    /// Eligible rows covered by generated rules.
    pub covered_rows: usize,
    /// Coverage ratio in the range `[0.0, 1.0]`.
    pub score: f64,
    /// Human-readable deterministic reasons.
    pub reasons: Vec<String>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
struct PackFile {
    version: String,
    id: String,
    #[serde(default)]
    rules: Vec<PackRule>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
struct PackRule {
    host: String,
    path_prefix: String,
    manifest: serde_json::Value,
}

/// Parses top-100 matrix rows relevant to compatibility lab tasks.
pub fn parse_top100_matrix(input: &str) -> Result<Vec<LabRow>, String> {
    let mut rows = Vec::new();
    for (line_number, line) in input.lines().enumerate() {
        let trimmed = line.trim();
        if trimmed.is_empty() || trimmed.starts_with('#') {
            continue;
        }
        let fields = trimmed.split('\t').collect::<Vec<_>>();
        if fields.len() < 9 {
            return Err(format!(
                "invalid top100 row at line {}: expected 9 fields, got {}",
                line_number + 1,
                fields.len()
            ));
        }
        let current_tier = parse_tier(fields[4], "top100", line_number + 1)?;
        rows.push(LabRow {
            source: CorpusSource::Top100,
            domain: fields[0].trim().to_owned(),
            family: canonical_family(fields[1]),
            intent: Some(fields[2].trim().to_owned()),
            current_tier,
            known_limit: fields[8].trim().to_owned(),
        });
    }
    Ok(rows)
}

/// Parses forum matrix rows relevant to compatibility lab tasks.
pub fn parse_forum_matrix(input: &str) -> Result<Vec<LabRow>, String> {
    let mut rows = Vec::new();
    for (line_number, line) in input.lines().enumerate() {
        let trimmed = line.trim();
        if trimmed.is_empty() || trimmed.starts_with('#') {
            continue;
        }
        let fields = trimmed.split('\t').collect::<Vec<_>>();
        if fields.len() < 8 {
            return Err(format!(
                "invalid forum row at line {}: expected 8 fields, got {}",
                line_number + 1,
                fields.len()
            ));
        }
        let current_tier = parse_tier(fields[3], "forum", line_number + 1)?;
        rows.push(LabRow {
            source: CorpusSource::Forum,
            domain: fields[0].trim().to_owned(),
            family: canonical_family(fields[1]),
            intent: None,
            current_tier,
            known_limit: fields[7].trim().to_owned(),
        });
    }
    Ok(rows)
}

/// Ingests corpus rows and optional capture artifacts.
pub fn ingest_summary(
    top100_matrix: &str,
    forum_matrix: &str,
    capture_artifacts: &[String],
) -> Result<IngestSummary, String> {
    let mut rows = parse_top100_matrix(top100_matrix)?;
    rows.extend(parse_forum_matrix(forum_matrix)?);
    rows.sort_by(|left, right| {
        (
            left.family.as_str(),
            left.domain.as_str(),
            left.source.as_str(),
            left.intent.as_deref().unwrap_or(""),
        )
            .cmp(&(
                right.family.as_str(),
                right.domain.as_str(),
                right.source.as_str(),
                right.intent.as_deref().unwrap_or(""),
            ))
    });

    let mut captures_total = 0usize;
    for artifact in capture_artifacts {
        validate_capture_bundle(artifact).map_err(|error| error.to_string())?;
        captures_total = captures_total.saturating_add(1);
    }

    let mut counts = BTreeMap::<String, usize>::new();
    for row in &rows {
        let counter = counts.entry(row.family.clone()).or_default();
        *counter = counter.saturating_add(1);
    }
    let family_counts = counts.into_iter().collect::<Vec<_>>();

    Ok(IngestSummary {
        rows,
        captures_total,
        family_counts,
    })
}

/// Suggests deterministic host/path rules for a family.
pub fn synthesize_rules(rows: &[LabRow], family: &str) -> Vec<PackRuleSuggestion> {
    let family = canonical_family(family);
    let mut entries = BTreeSet::new();
    for row in rows {
        if row.family != family {
            continue;
        }
        let (host, path_prefix) = domain_to_host_path_prefix(&row.domain);
        entries.insert((host, path_prefix));
    }
    entries
        .into_iter()
        .map(|(host, path_prefix)| PackRuleSuggestion { host, path_prefix })
        .collect()
}

/// Computes deterministic synthesis quality for one family.
pub fn synthesize_quality(
    rows: &[LabRow],
    family: &str,
    rules: &[PackRuleSuggestion],
) -> SynthesisQuality {
    let family = canonical_family(family);
    let eligible = rows
        .iter()
        .filter(|row| row.family == family && row.known_limit == "none")
        .collect::<Vec<_>>();

    let covered_rows = eligible
        .iter()
        .filter(|row| {
            let (host, path_prefix) = domain_to_host_path_prefix(&row.domain);
            rules
                .iter()
                .any(|rule| rule.host == host && rule.path_prefix == path_prefix)
        })
        .count();
    let eligible_rows = eligible.len();
    let score = if eligible_rows == 0 {
        1.0
    } else {
        covered_rows as f64 / eligible_rows as f64
    };
    let mut reasons = Vec::new();
    if eligible_rows == 0 {
        reasons.push("no eligible rows (known_limit=none) for family".to_owned());
    } else if covered_rows == eligible_rows {
        reasons.push("all eligible rows map to synthesized host/path rules".to_owned());
    } else {
        reasons.push(format!(
            "{}/{} eligible rows covered by synthesized rules",
            covered_rows, eligible_rows
        ));
    }
    SynthesisQuality {
        family,
        eligible_rows,
        covered_rows,
        score,
        reasons,
    }
}

/// Creates a deterministic scaffold pack JSON.
pub fn scaffold_pack_json(rows: &[LabRow], family: &str) -> Result<String, String> {
    let rules = synthesize_rules(rows, family);
    let canonical_family = canonical_family(family);
    let id = format!("family.{canonical_family}");
    let pack_rules = rules
        .into_iter()
        .map(|rule| {
            json!({
                "host": rule.host,
                "path_prefix": rule.path_prefix,
                "manifest": {
                    "version": "index.idx/v1",
                    "scope": "/",
                    "content": {
                        "main_selector": "main, article, [role='main']"
                    },
                    "regions": [],
                    "fields": [],
                    "forms": [],
                    "dates": []
                }
            })
        })
        .collect::<Vec<_>>();
    let output = json!({
        "version": "index.pack/v1",
        "id": id,
        "rules": pack_rules
    });
    serde_json::to_string_pretty(&output).map_err(|error| error.to_string())
}

/// Lints synthesized or edited pack JSON for common unsafe patterns.
pub fn lint_pack_json(input: &str) -> Result<PackLintReport, String> {
    let pack = serde_json::from_str::<PackFile>(input)
        .map_err(|error| format!("pack JSON is invalid: {error}"))?;
    let mut errors = Vec::new();
    let mut warnings = Vec::new();
    if pack.version != "index.pack/v1" {
        errors.push(format!("unsupported pack version: {}", pack.version));
    }
    if pack.id.trim().is_empty() {
        errors.push("pack id must not be empty".to_owned());
    }

    for (index, rule) in pack.rules.iter().enumerate() {
        if rule.host.contains('*')
            || rule.host.starts_with('.')
            || rule.host.contains(' ')
            || !rule.host.contains('.')
        {
            errors.push(format!("rule {} host is invalid: {}", index + 1, rule.host));
        }
        if !rule.path_prefix.starts_with('/') || rule.path_prefix.contains('*') {
            errors.push(format!(
                "rule {} has invalid path_prefix {}",
                index + 1,
                rule.path_prefix
            ));
        }
        if let Some(version) = rule
            .manifest
            .get("version")
            .and_then(|value| value.as_str())
        {
            if version != "index.idx/v1" {
                errors.push(format!(
                    "rule {} has unsupported manifest version: {}",
                    index + 1,
                    version
                ));
            }
        }
        if let Some(selector) = rule
            .manifest
            .get("content")
            .and_then(|content| content.get("main_selector"))
            .and_then(|selector| selector.as_str())
        {
            let selector_lower = selector.to_ascii_lowercase();
            if selector_lower.contains("script") || selector_lower.contains("iframe") {
                errors.push(format!(
                    "rule {} has unsafe main_selector: {}",
                    index + 1,
                    selector
                ));
            }
        }
        let field_names = rule
            .manifest
            .get("fields")
            .and_then(|fields| fields.as_array())
            .cloned()
            .unwrap_or_default();
        for field in field_names {
            if let Some(name) = field.get("name").and_then(|value| value.as_str()) {
                let lower = name.to_ascii_lowercase();
                if lower.contains("password") || lower.contains("token") || lower.contains("cookie")
                {
                    errors.push(format!(
                        "rule {} field hint is sensitive and unsupported: {}",
                        index + 1,
                        name
                    ));
                }
            }
        }
        if rule.manifest.get("dates").is_none() {
            warnings.push(format!(
                "rule {} does not define date hints; output may be less consistent",
                index + 1
            ));
        }
    }

    Ok(PackLintReport { errors, warnings })
}

/// Merges override pack rules into a generated pack.
pub fn merge_pack_overrides(generated: &str, overrides: &str) -> Result<String, String> {
    let mut base = serde_json::from_str::<PackFile>(generated)
        .map_err(|error| format!("generated pack JSON is invalid: {error}"))?;
    let override_pack = serde_json::from_str::<PackFile>(overrides)
        .map_err(|error| format!("override pack JSON is invalid: {error}"))?;

    if base.version != override_pack.version {
        return Err("override version must match generated pack version".to_owned());
    }

    let mut by_key = BTreeMap::new();
    for rule in base.rules {
        by_key.insert((rule.host.clone(), rule.path_prefix.clone()), rule);
    }
    for rule in override_pack.rules {
        by_key.insert((rule.host.clone(), rule.path_prefix.clone()), rule);
    }
    base.rules = by_key.into_values().collect();

    serde_json::to_string_pretty(&base).map_err(|error| error.to_string())
}

fn parse_tier(value: &str, source: &str, line_number: usize) -> Result<u8, String> {
    let parsed = value
        .trim()
        .parse::<u8>()
        .map_err(|error| format!("invalid {source} tier at line {line_number}: {error}"))?;
    if parsed > 5 {
        return Err(format!(
            "invalid {source} tier at line {line_number}: {parsed} (expected 0..=5)"
        ));
    }
    Ok(parsed)
}

fn canonical_family(value: &str) -> String {
    match value.trim().to_ascii_lowercase().as_str() {
        "reddit" | "generic-forum" => "social-community".to_owned(),
        other => other.to_owned(),
    }
}

fn domain_to_host_path_prefix(domain: &str) -> (String, String) {
    let trimmed = domain.trim();
    if let Some((host, path)) = trimmed.split_once('/') {
        let prefix = format!("/{}", path.trim_start_matches('/'));
        return (
            host.trim().to_ascii_lowercase(),
            if prefix == "/" {
                "/".to_owned()
            } else {
                prefix
            },
        );
    }
    (trimmed.to_ascii_lowercase(), "/".to_owned())
}

#[cfg(test)]
mod tests {
    use super::{
        ingest_summary, lint_pack_json, merge_pack_overrides, parse_forum_matrix,
        parse_top100_matrix, scaffold_pack_json, synthesize_quality, synthesize_rules,
    };

    #[test]
    fn parses_matrix_rows_and_canonicalizes_families() -> Result<(), Box<dyn std::error::Error>> {
        let top100 = "# domain\tfamily\tprimary_intent\tmin_tier\tcurrent_tier\tfixture\texpected_path\tstatus\tknown_limit\nreddit.example\treddit\tfeed-or-thread\t1\t1\ta.html\tgeneric\tpartial\tnone\n";
        let forum = "# domain\tfamily\tmin_tier\tcurrent_tier\tfixture\texpected_path\tstatus\tknown_limit\nforum.example\tgeneric-forum\t1\t1\ta.html\tgeneric\tpartial\tnone\n";
        let parsed_top = parse_top100_matrix(top100)?;
        let parsed_forum = parse_forum_matrix(forum)?;
        assert_eq!(parsed_top.len(), 1);
        assert_eq!(parsed_forum.len(), 1);
        assert_eq!(parsed_top[0].family, "social-community");
        assert_eq!(parsed_forum[0].family, "social-community");
        Ok(())
    }

    #[test]
    fn ingest_summary_is_deterministic_for_row_order() -> Result<(), Box<dyn std::error::Error>> {
        let top100_a = "# domain\tfamily\tprimary_intent\tmin_tier\tcurrent_tier\tfixture\texpected_path\tstatus\tknown_limit\nb.example\tsearch-portal\tsearch-results\t1\t1\ta.html\tgeneric\tpartial\tnone\na.example\tsearch-portal\tsearch-results\t1\t1\ta.html\tgeneric\tpartial\tnone\n";
        let top100_b = "# domain\tfamily\tprimary_intent\tmin_tier\tcurrent_tier\tfixture\texpected_path\tstatus\tknown_limit\na.example\tsearch-portal\tsearch-results\t1\t1\ta.html\tgeneric\tpartial\tnone\nb.example\tsearch-portal\tsearch-results\t1\t1\ta.html\tgeneric\tpartial\tnone\n";
        let forum = "# domain\tfamily\tmin_tier\tcurrent_tier\tfixture\texpected_path\tstatus\tknown_limit\nforum.example\tlegacy-forum\t1\t1\ta.html\tgeneric\tpartial\tnone\n";
        let summary_a = ingest_summary(top100_a, forum, &[])?;
        let summary_b = ingest_summary(top100_b, forum, &[])?;
        assert_eq!(summary_a.rows, summary_b.rows);
        assert_eq!(summary_a.family_counts, summary_b.family_counts);
        Ok(())
    }

    #[test]
    fn synthesize_and_scaffold_are_deterministic() -> Result<(), Box<dyn std::error::Error>> {
        let top100 = "# domain\tfamily\tprimary_intent\tmin_tier\tcurrent_tier\tfixture\texpected_path\tstatus\tknown_limit\nexample.org/docs\tknowledge-reference\tarticle\t1\t1\ta.html\tgeneric\tpartial\tnone\nexample.org/help\tknowledge-reference\tarticle\t1\t1\ta.html\tgeneric\tpartial\tnone\n";
        let forum = "# domain\tfamily\tmin_tier\tcurrent_tier\tfixture\texpected_path\tstatus\tknown_limit\nforum.example\tlegacy-forum\t1\t1\ta.html\tgeneric\tpartial\tnone\n";
        let summary = ingest_summary(top100, forum, &[])?;
        let rules = synthesize_rules(&summary.rows, "knowledge-reference");
        assert_eq!(rules.len(), 2);
        let scaffold_a = scaffold_pack_json(&summary.rows, "knowledge-reference")?;
        let scaffold_b = scaffold_pack_json(&summary.rows, "knowledge-reference")?;
        assert_eq!(scaffold_a, scaffold_b);
        assert!(scaffold_a.contains("\"version\": \"index.pack/v1\""));
        Ok(())
    }

    #[test]
    fn lint_rejects_unsafe_selectors_and_sensitive_fields() -> Result<(), Box<dyn std::error::Error>>
    {
        let report = lint_pack_json(
            r#"{
  "version": "index.pack/v1",
  "id": "unsafe-pack",
  "rules": [
    {
      "host": "example.org",
      "path_prefix": "/docs*",
      "manifest": {
        "content": { "main_selector": "main script" },
        "fields": [{ "name": "auth_token" }]
      }
    }
  ]
}"#,
        )?;
        assert!(!report.passed());
        assert!(
            report
                .errors
                .iter()
                .any(|error| error.contains("invalid path_prefix"))
        );
        assert!(
            report
                .errors
                .iter()
                .any(|error| error.contains("unsafe main_selector"))
        );
        assert!(
            report
                .errors
                .iter()
                .any(|error| error.contains("sensitive"))
        );
        Ok(())
    }

    #[test]
    fn lint_rejects_wildcard_hosts_and_manifest_version_mismatch()
    -> Result<(), Box<dyn std::error::Error>> {
        let report = lint_pack_json(
            r#"{
  "version": "index.pack/v1",
  "id": "unsafe-hosts",
  "rules": [
    {
      "host": "*.example.org",
      "path_prefix": "/docs",
      "manifest": {
        "version": "index.idx/v2",
        "content": { "main_selector": "main article" }
      }
    }
  ]
}"#,
        )?;
        assert!(!report.passed());
        assert!(
            report
                .errors
                .iter()
                .any(|error| error.contains("host is invalid"))
        );
        assert!(
            report
                .errors
                .iter()
                .any(|error| error.contains("unsupported manifest version"))
        );
        Ok(())
    }

    #[test]
    fn synthesis_quality_scores_eligible_row_coverage() -> Result<(), Box<dyn std::error::Error>> {
        let top100 = "# domain\tfamily\tprimary_intent\tmin_tier\tcurrent_tier\tfixture\texpected_path\tstatus\tknown_limit\nexample.org/docs\tknowledge-reference\tarticle\t1\t1\ta.html\tgeneric\tpartial\tnone\nexample.org/help\tknowledge-reference\tarticle\t1\t1\ta.html\tgeneric\tpartial\tnone\n";
        let forum = "# domain\tfamily\tmin_tier\tcurrent_tier\tfixture\texpected_path\tstatus\tknown_limit\nforum.example\tlegacy-forum\t1\t1\ta.html\tgeneric\tpartial\tnone\n";
        let summary = ingest_summary(top100, forum, &[])?;
        let rules = synthesize_rules(&summary.rows, "knowledge-reference");
        let quality = synthesize_quality(&summary.rows, "knowledge-reference", &rules);
        assert_eq!(quality.eligible_rows, 2);
        assert_eq!(quality.covered_rows, 2);
        assert!((quality.score - 1.0).abs() < f64::EPSILON);
        assert!(
            quality
                .reasons
                .iter()
                .any(|reason| reason.contains("all eligible rows"))
        );
        Ok(())
    }

    #[test]
    fn merge_overrides_replaces_matching_rules() -> Result<(), Box<dyn std::error::Error>> {
        let generated = r#"{
  "version": "index.pack/v1",
  "id": "family.docs",
  "rules": [
    { "host": "example.org", "path_prefix": "/docs", "manifest": {"content":{"main_selector":"main"}} }
  ]
}"#;
        let overrides = r#"{
  "version": "index.pack/v1",
  "id": "family.docs",
  "rules": [
    { "host": "example.org", "path_prefix": "/docs", "manifest": {"content":{"main_selector":"article"}} },
    { "host": "example.net", "path_prefix": "/", "manifest": {"content":{"main_selector":"main"}} }
  ]
}"#;
        let merged = merge_pack_overrides(generated, overrides)?;
        assert!(merged.contains("\"example.org\""));
        assert!(merged.contains("\"example.net\""));
        assert!(merged.contains("\"article\""));
        Ok(())
    }
}