llmwiki-tooling 0.1.1

use std::collections::HashSet;
use std::path::Path;

use serde::Deserialize;

use crate::error::ConfigError;

/// Severity level for a check or rule.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum Severity {
    /// Causes non-zero exit code.
    #[default]
    Error,
    /// Prints finding but does not affect exit code.
    Warn,
    /// Suppressed entirely.
    Off,
}

impl std::fmt::Display for Severity {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Error => f.write_str("error"),
            Self::Warn => f.write_str("warn"),
            Self::Off => f.write_str("off"),
        }
    }
}

impl<'de> Deserialize<'de> for Severity {
    fn deserialize<D: serde::Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
        let s = String::deserialize(deserializer)?;
        match s.as_str() {
            "error" => Ok(Self::Error),
            "warn" => Ok(Self::Warn),
            "off" => Ok(Self::Off),
            other => Err(serde::de::Error::unknown_variant(
                other,
                &["error", "warn", "off"],
            )),
        }
    }
}

/// Complete wiki configuration, parsed from `wiki.toml` or auto-detected.
#[derive(Debug, Clone)]
pub struct WikiConfig {
    /// Path to the index file relative to wiki root. `None` means no index file.
    pub index: Option<String>,
    /// Content directories, sorted most-specific-first for resolution.
    pub directories: Vec<DirectoryConfig>,
    /// Linking behavior settings.
    pub linking: LinkingConfig,
    /// Wiki-wide structural check severities.
    pub checks: ChecksConfig,
    /// Parameterized rules scoped to directories.
    pub rules: Vec<RuleConfig>,
}

/// A directory containing wiki pages.
#[derive(Debug, Clone)]
pub struct DirectoryConfig {
    /// Path relative to wiki root.
    pub path: String,
    /// Whether pages in this directory feed bare mention detection.
    pub autolink: bool,
}

/// Global linking behavior.
#[derive(Debug, Clone)]
pub struct LinkingConfig {
    /// Page names to never auto-link.
    pub exclude: HashSet<String>,
    /// Frontmatter field for per-page auto-link opt-out.
    pub autolink_field: String,
}

/// Wiki-wide structural check severities.
#[derive(Debug, Clone)]
pub struct ChecksConfig {
    pub broken_links: Severity,
    pub orphan_pages: Severity,
    pub index_coverage: Severity,
}

/// A parameterized rule scoped to specific directories.
#[derive(Debug, Clone)]
pub enum RuleConfig {
    RequiredSections {
        dirs: Vec<String>,
        sections: Vec<String>,
        severity: Severity,
    },
    RequiredFrontmatter {
        dirs: Vec<String>,
        fields: Vec<String>,
        severity: Severity,
    },
    MirrorParity {
        left: String,
        right: String,
        severity: Severity,
    },
    CitationPattern {
        name: String,
        dirs: Vec<String>,
        pattern: String,
        match_in: String,
        match_mode: MatchMode,
        severity: Severity,
    },
}

impl RuleConfig {
    pub fn severity(&self) -> Severity {
        match self {
            Self::RequiredSections { severity, .. }
            | Self::RequiredFrontmatter { severity, .. }
            | Self::MirrorParity { severity, .. }
            | Self::CitationPattern { severity, .. } => *severity,
        }
    }
}

/// How a citation pattern match is verified against `match_in` pages.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub enum MatchMode {
    /// Search page file contents for the captured ID string.
    #[default]
    Content,
    /// Check if a page with the captured ID as its filename exists.
    Filename,
}

impl<'de> Deserialize<'de> for MatchMode {
    fn deserialize<D: serde::Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
        let s = String::deserialize(deserializer)?;
        match s.as_str() {
            "content" => Ok(Self::Content),
            "filename" => Ok(Self::Filename),
            other => Err(serde::de::Error::unknown_variant(
                other,
                &["content", "filename"],
            )),
        }
    }
}

// --- TOML deserialization types ---

#[derive(Deserialize)]
struct RawConfig {
    index: Option<String>,
    #[serde(default)]
    directories: Vec<RawDirectoryConfig>,
    #[serde(default)]
    linking: RawLinkingConfig,
    #[serde(default)]
    checks: RawChecksConfig,
    #[serde(default)]
    rules: Vec<RawRuleConfig>,
}

#[derive(Deserialize)]
struct RawDirectoryConfig {
    path: String,
    #[serde(default = "default_true")]
    autolink: bool,
}

fn default_true() -> bool {
    true
}

#[derive(Deserialize, Default)]
struct RawLinkingConfig {
    #[serde(default)]
    exclude: Vec<String>,
    #[serde(default = "default_autolink_field")]
    autolink_field: String,
}

fn default_autolink_field() -> String {
    "autolink".to_owned()
}

#[derive(Deserialize, Default)]
struct RawChecksConfig {
    #[serde(default)]
    broken_links: Option<Severity>,
    #[serde(default)]
    orphan_pages: Option<Severity>,
    #[serde(default)]
    index_coverage: Option<Severity>,
}

#[derive(Deserialize)]
#[serde(tag = "check")]
enum RawRuleConfig {
    #[serde(rename = "required-sections")]
    RequiredSections {
        dirs: Vec<String>,
        sections: Vec<String>,
        #[serde(default)]
        severity: Option<Severity>,
    },
    #[serde(rename = "required-frontmatter")]
    RequiredFrontmatter {
        dirs: Vec<String>,
        fields: Vec<String>,
        #[serde(default)]
        severity: Option<Severity>,
    },
    #[serde(rename = "mirror-parity")]
    MirrorParity {
        left: String,
        right: String,
        #[serde(default)]
        severity: Option<Severity>,
    },
    #[serde(rename = "citation-pattern")]
    CitationPattern {
        name: String,
        dirs: Vec<String>,
        #[serde(default)]
        pattern: Option<String>,
        #[serde(default)]
        preset: Option<String>,
        match_in: String,
        #[serde(default)]
        match_mode: Option<MatchMode>,
        #[serde(default)]
        severity: Option<Severity>,
    },
}

/// Built-in citation pattern presets.
fn resolve_preset(name: &str) -> Result<(String, MatchMode), ConfigError> {
    match name {
        "bold-method-year" => Ok((
            r"\*\*(?P<id>[A-Za-z][A-Za-z0-9-]+)\*\*\s*\([^)]*\d{4}[^)]*\)".to_owned(),
            MatchMode::Filename,
        )),
        other => Err(ConfigError::UnknownPreset(other.to_owned())),
    }
}

impl WikiConfig {
    /// Load config from `wiki.toml` in the given root directory.
    /// Returns `None` if `wiki.toml` doesn't exist.
    pub fn load(root: &Path) -> Result<Option<Self>, ConfigError> {
        let config_path = root.join("wiki.toml");
        let content = match std::fs::read_to_string(&config_path) {
            Ok(content) => content,
            Err(e) if e.kind() == std::io::ErrorKind::NotFound => return Ok(None),
            Err(e) => {
                return Err(ConfigError::Read {
                    path: config_path,
                    source: e,
                });
            }
        };
        let raw: RawConfig = toml::from_str(&content).map_err(|e| ConfigError::Parse {
            path: config_path,
            source: e,
        })?;
        Self::from_raw(raw).map(Some)
    }

    /// Auto-detect config when no `wiki.toml` exists.
    pub fn auto_detect(root: &Path) -> Self {
        let has_wiki_dir = root.join("wiki").is_dir();
        let dir_path = if has_wiki_dir { "wiki" } else { "." };

        Self {
            index: Some("index.md".to_owned()),
            directories: vec![DirectoryConfig {
                path: dir_path.to_owned(),
                autolink: true,
            }],
            linking: LinkingConfig {
                exclude: HashSet::new(),
                autolink_field: default_autolink_field(),
            },
            checks: ChecksConfig {
                broken_links: Severity::Error,
                orphan_pages: Severity::Error,
                index_coverage: Severity::Error,
            },
            rules: Vec::new(),
        }
    }

    /// Load config from wiki.toml if present, otherwise auto-detect.
    pub fn load_or_detect(root: &Path) -> Result<Self, ConfigError> {
        match Self::load(root)? {
            Some(config) => Ok(config),
            None => Ok(Self::auto_detect(root)),
        }
    }

    fn from_raw(raw: RawConfig) -> Result<Self, ConfigError> {
        let mut directories: Vec<DirectoryConfig> = if raw.directories.is_empty() {
            // No directories declared — auto-detect
            vec![DirectoryConfig {
                path: "wiki".to_owned(),
                autolink: true,
            }]
        } else {
            raw.directories
                .into_iter()
                .map(|d| DirectoryConfig {
                    path: normalize_path(&d.path),
                    autolink: d.autolink,
                })
                .collect()
        };

        // Sort most-specific first (longest path) for resolution
        directories.sort_by(|a, b| b.path.len().cmp(&a.path.len()));

        let linking = LinkingConfig {
            exclude: raw.linking.exclude.into_iter().collect(),
            autolink_field: raw.linking.autolink_field,
        };

        let checks = ChecksConfig {
            broken_links: raw.checks.broken_links.unwrap_or(Severity::Error),
            orphan_pages: raw.checks.orphan_pages.unwrap_or(Severity::Error),
            index_coverage: raw.checks.index_coverage.unwrap_or(Severity::Error),
        };

        let mut rules = Vec::new();
        for raw_rule in raw.rules {
            rules.push(convert_rule(raw_rule)?);
        }

        // Validate citation patterns compile as regex
        for rule in &rules {
            if let RuleConfig::CitationPattern { pattern, name, .. } = rule {
                regex_lite::Regex::new(pattern).map_err(|e| ConfigError::InvalidPattern {
                    name: name.clone(),
                    source: e,
                })?;
            }
        }

        Ok(Self {
            index: match raw.index {
                Some(s) if s.is_empty() => None,
                Some(s) => Some(s),
                None => Some("index.md".to_owned()),
            },
            directories,
            linking,
            checks,
            rules,
        })
    }

    /// Get the directory config that applies to a given relative path.
    /// Returns the most-specific matching directory (longest prefix match).
    pub fn directory_for(&self, rel_path: &Path) -> Option<&DirectoryConfig> {
        let rel_str = rel_path.to_str()?;
        // Directories are sorted most-specific first
        self.directories
            .iter()
            .find(|d| rel_str.starts_with(&d.path) || d.path == ".")
    }

    /// Check if a page at the given relative path should be auto-linked.
    pub fn is_autolink_dir(&self, rel_path: &Path) -> bool {
        self.directory_for(rel_path)
            .map(|d| d.autolink)
            .unwrap_or(false)
    }

    /// Check if a relative path matches a directory prefix from a rule's `dirs` list.
    pub fn matches_dirs(rel_path: &Path, dirs: &[String]) -> bool {
        let Some(rel_str) = rel_path.to_str() else {
            return false;
        };
        dirs.iter().any(|d| rel_str.starts_with(d.as_str()))
    }

    /// All mirror-parity rules' `right` paths (non-wiki directories used for parity checks).
    pub fn mirror_paths(&self) -> Vec<(&str, &str)> {
        self.rules
            .iter()
            .filter_map(|r| match r {
                RuleConfig::MirrorParity { left, right, .. } => {
                    Some((left.as_str(), right.as_str()))
                }
                _ => None,
            })
            .collect()
    }
}

fn convert_rule(raw: RawRuleConfig) -> Result<RuleConfig, ConfigError> {
    match raw {
        RawRuleConfig::RequiredSections {
            dirs,
            sections,
            severity,
        } => Ok(RuleConfig::RequiredSections {
            dirs: dirs.into_iter().map(|d| normalize_path(&d)).collect(),
            sections,
            severity: severity.unwrap_or(Severity::Error),
        }),
        RawRuleConfig::RequiredFrontmatter {
            dirs,
            fields,
            severity,
        } => Ok(RuleConfig::RequiredFrontmatter {
            dirs: dirs.into_iter().map(|d| normalize_path(&d)).collect(),
            fields,
            severity: severity.unwrap_or(Severity::Error),
        }),
        RawRuleConfig::MirrorParity {
            left,
            right,
            severity,
        } => Ok(RuleConfig::MirrorParity {
            left: normalize_path(&left),
            right: normalize_path(&right),
            severity: severity.unwrap_or(Severity::Error),
        }),
        RawRuleConfig::CitationPattern {
            name,
            dirs,
            pattern,
            preset,
            match_in,
            match_mode,
            severity,
        } => {
            let (resolved_pattern, resolved_mode) = match (pattern, preset) {
                (Some(p), None) => (p, match_mode.unwrap_or(MatchMode::Content)),
                (None, Some(preset_name)) => {
                    let (p, m) = resolve_preset(&preset_name)?;
                    (p, match_mode.unwrap_or(m))
                }
                (Some(_), Some(_)) => {
                    return Err(ConfigError::Validation(format!(
                        "citation-pattern '{name}': cannot specify both 'pattern' and 'preset'"
                    )));
                }
                (None, None) => {
                    return Err(ConfigError::Validation(format!(
                        "citation-pattern '{name}': must specify either 'pattern' or 'preset'"
                    )));
                }
            };
            Ok(RuleConfig::CitationPattern {
                name,
                dirs: dirs.into_iter().map(|d| normalize_path(&d)).collect(),
                pattern: resolved_pattern,
                match_in: normalize_path(&match_in),
                match_mode: resolved_mode,
                severity: severity.unwrap_or(Severity::Warn),
            })
        }
    }
}

/// Strip trailing slashes for consistent prefix matching.
fn normalize_path(path: &str) -> String {
    path.trim_end_matches('/').to_owned()
}

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

    #[test]
    fn parses_minimal_config() {
        let toml = r#"
[[directories]]
path = "wiki"
"#;
        let raw: RawConfig = toml::from_str(toml).unwrap();
        let config = WikiConfig::from_raw(raw).unwrap();
        assert_eq!(config.directories.len(), 1);
        assert_eq!(config.directories[0].path, "wiki");
        assert!(config.directories[0].autolink);
        assert_eq!(config.checks.broken_links, Severity::Error);
    }

    #[test]
    fn parses_full_config() {
        let toml = r#"
index = "contents.md"

[[directories]]
path = "wiki"

[[directories]]
path = "wiki/papers"
autolink = false

[linking]
exclude = ["the", "a"]
autolink_field = "auto"

[checks]
broken_links = "error"
orphan_pages = "warn"
index_coverage = "off"

[[rules]]
check = "required-sections"
dirs = ["wiki/concepts"]
sections = ["See also"]
severity = "error"

[[rules]]
check = "mirror-parity"
left = "wiki/papers"
right = "raw/papers"
severity = "warn"

[[rules]]
check = "citation-pattern"
name = "arxiv"
dirs = ["wiki"]
pattern = 'arxiv\.org/abs/(?P<id>\d{4}\.\d{4,5})'
match_in = "wiki/papers"
severity = "warn"

[[rules]]
check = "citation-pattern"
name = "bold-method"
preset = "bold-method-year"
dirs = ["wiki"]
match_in = "wiki/papers"
severity = "warn"
"#;
        let raw: RawConfig = toml::from_str(toml).unwrap();
        let config = WikiConfig::from_raw(raw).unwrap();

        assert_eq!(config.index.as_deref(), Some("contents.md"));
        assert!(config.linking.exclude.contains("the"));
        assert_eq!(config.linking.autolink_field, "auto");
        assert_eq!(config.checks.orphan_pages, Severity::Warn);
        assert_eq!(config.checks.index_coverage, Severity::Off);
        assert_eq!(config.rules.len(), 4);

        // Most specific directory first
        assert_eq!(config.directories[0].path, "wiki/papers");
        assert!(!config.directories[0].autolink);
        assert_eq!(config.directories[1].path, "wiki");
        assert!(config.directories[1].autolink);
    }

    #[test]
    fn directory_resolution_most_specific_wins() {
        let config = WikiConfig {
            index: None,
            directories: vec![
                DirectoryConfig {
                    path: "wiki/papers".to_owned(),
                    autolink: false,
                },
                DirectoryConfig {
                    path: "wiki".to_owned(),
                    autolink: true,
                },
            ],
            linking: LinkingConfig {
                exclude: HashSet::new(),
                autolink_field: "autolink".to_owned(),
            },
            checks: ChecksConfig {
                broken_links: Severity::Error,
                orphan_pages: Severity::Error,
                index_coverage: Severity::Error,
            },
            rules: Vec::new(),
        };

        assert!(config.is_autolink_dir(Path::new("wiki/concepts/GRPO.md")));
        assert!(!config.is_autolink_dir(Path::new("wiki/papers/deepseek.md")));
    }

    #[test]
    fn auto_detect_with_wiki_dir() {
        let dir = tempfile::tempdir().unwrap();
        std::fs::create_dir(dir.path().join("wiki")).unwrap();
        std::fs::write(dir.path().join("index.md"), "# Index").unwrap();

        let config = WikiConfig::auto_detect(dir.path());
        assert_eq!(config.directories[0].path, "wiki");
        assert_eq!(config.index.as_deref(), Some("index.md"));
    }

    #[test]
    fn auto_detect_flat_wiki() {
        let dir = tempfile::tempdir().unwrap();
        std::fs::write(dir.path().join("index.md"), "# Index").unwrap();

        let config = WikiConfig::auto_detect(dir.path());
        assert_eq!(config.directories[0].path, ".");
    }

    #[test]
    fn rejects_pattern_and_preset_together() {
        let toml = r#"
[[rules]]
check = "citation-pattern"
name = "test"
dirs = ["wiki"]
pattern = "foo"
preset = "bold-method-year"
match_in = "wiki"
"#;
        let raw: RawConfig = toml::from_str(toml).unwrap();
        let err = WikiConfig::from_raw(raw).unwrap_err();
        assert!(err.to_string().contains("cannot specify both"));
    }

    #[test]
    fn rejects_unknown_preset() {
        let toml = r#"
[[rules]]
check = "citation-pattern"
name = "test"
dirs = ["wiki"]
preset = "nonexistent"
match_in = "wiki"
"#;
        let raw: RawConfig = toml::from_str(toml).unwrap();
        let err = WikiConfig::from_raw(raw).unwrap_err();
        assert!(err.to_string().contains("nonexistent"));
    }

    #[test]
    fn matches_dirs_prefix() {
        assert!(WikiConfig::matches_dirs(
            Path::new("wiki/concepts/GRPO.md"),
            &["wiki/concepts".to_owned()]
        ));
        assert!(WikiConfig::matches_dirs(
            Path::new("wiki/concepts/GRPO.md"),
            &["wiki".to_owned()]
        ));
        assert!(!WikiConfig::matches_dirs(
            Path::new("wiki/papers/foo.md"),
            &["wiki/concepts".to_owned()]
        ));
    }
}