taudit-parse-gitlab 0.9.0

use std::collections::HashMap;

use serde::Deserialize;
use serde_yaml::Value;
use taudit_core::error::TauditError;
use taudit_core::graph::*;
use taudit_core::ports::PipelineParser;

/// GitLab CI YAML parser.
///
/// Parses `.gitlab-ci.yml` files into an `AuthorityGraph`. The authority model:
/// - Each job is a `Step` node.
/// - `CI_JOB_TOKEN` is a global implicit `Identity` (always present, scope=broad).
/// - `secrets:` entries emit `Secret` nodes with `HasAccessTo` edges.
/// - `id_tokens:` entries emit OIDC `Identity` nodes.
/// - `variables:` entries with credential-pattern names emit `Secret` nodes.
/// - `image:` and `services:` emit `Image` nodes with `UsesImage` edges.
/// - `include:` and `extends:` mark the graph `Partial`.
/// - `rules: if: merge_request_event` and `only: merge_requests` set `META_TRIGGER`.
pub struct GitlabParser;

/// Reserved top-level keys that are not job definitions.
const RESERVED: &[&str] = &[
    "stages",
    "workflow",
    "include",
    "variables",
    "image",
    "services",
    "default",
    "cache",
    "before_script",
    "after_script",
    "types",
];

/// Variable name fragments that indicate a credential rather than plain config.
const CRED_FRAGMENTS: &[&str] = &[
    "TOKEN",
    "SECRET",
    "PASSWORD",
    "PASSWD",
    "PRIVATE_KEY",
    "API_KEY",
    "APIKEY",
    "SIGNING_KEY",
    "ACCESS_KEY",
    "SERVICE_ACCOUNT",
    "CERT",
    "CREDENTIAL",
];

impl PipelineParser for GitlabParser {
    fn platform(&self) -> &str {
        "gitlab-ci"
    }

    fn parse(&self, content: &str, source: &PipelineSource) -> Result<AuthorityGraph, TauditError> {
        let mut de = serde_yaml::Deserializer::from_str(content);
        let doc = de
            .next()
            .ok_or_else(|| TauditError::Parse("empty YAML document".into()))?;
        let root: Value = Value::deserialize(doc)
            .map_err(|e| TauditError::Parse(format!("YAML parse error: {e}")))?;

        let mapping = root
            .as_mapping()
            .ok_or_else(|| TauditError::Parse("GitLab CI root must be a mapping".into()))?;

        let mut graph = AuthorityGraph::new(source.clone());

        // CI_JOB_TOKEN is always present in every GitLab CI job — it's the built-in
        // platform token, equivalent to ADO's System.AccessToken or GHA's GITHUB_TOKEN.
        let mut meta = HashMap::new();
        meta.insert(META_IDENTITY_SCOPE.into(), "broad".into());
        meta.insert(META_IMPLICIT.into(), "true".into());
        let token_id = graph.add_node_with_metadata(
            NodeKind::Identity,
            "CI_JOB_TOKEN",
            TrustZone::FirstParty,
            meta,
        );

        // Top-level include: → mark Partial immediately
        if mapping.contains_key("include") {
            graph.mark_partial(
                "include: directive present — included templates not resolved".to_string(),
            );
        }

        // Global variables
        let global_secrets = process_variables(mapping.get("variables"), &mut graph, "pipeline");

        // Global image
        let global_image = mapping.get("image").and_then(extract_image_str);

        // Top-level merge_request trigger detection from `workflow:` rules
        if let Some(wf) = mapping.get("workflow") {
            if has_mr_trigger_in_workflow(wf) {
                graph
                    .metadata
                    .insert(META_TRIGGER.into(), "merge_request".into());
            }
        }

        // Process each job (any top-level key not in RESERVED)
        for (key, value) in mapping {
            let job_name = match key.as_str() {
                Some(k) => k,
                None => continue,
            };
            if RESERVED.contains(&job_name) {
                continue;
            }

            // Hidden jobs (starting with a dot) are templates — mark Partial, skip
            if job_name.starts_with('.') {
                graph.mark_partial(format!(
                    "job '{job_name}' is a hidden/template job — not resolved"
                ));
                continue;
            }

            let job_map = match value.as_mapping() {
                Some(m) => m,
                None => continue,
            };

            // extends: — job template inheritance, can't resolve statically
            if job_map.contains_key("extends") {
                graph.mark_partial(format!(
                    "job '{job_name}' uses extends: — inherited configuration not resolved"
                ));
            }

            // Detect PR/MR trigger in this job's rules: or only:
            let job_triggers_mr = job_has_mr_trigger(job_map);

            // Propagate job MR trigger to graph level
            if job_triggers_mr && !graph.metadata.contains_key(META_TRIGGER) {
                graph
                    .metadata
                    .insert(META_TRIGGER.into(), "merge_request".into());
            }

            // Job-level variables
            let job_secrets = process_variables(job_map.get("variables"), &mut graph, job_name);

            // Job-level explicit secrets: (Vault, AWS Secrets Manager, GCP, Azure)
            let explicit_secrets =
                process_explicit_secrets(job_map.get("secrets"), job_name, &mut graph);

            // Job-level OIDC tokens (id_tokens:)
            let oidc_identities = process_id_tokens(job_map.get("id_tokens"), job_name, &mut graph);

            // Job image (falls back to global)
            let job_image_str = job_map
                .get("image")
                .and_then(extract_image_str)
                .or(global_image.as_deref().map(String::from));

            let image_id = job_image_str.as_deref().map(|img| {
                let pinned = is_docker_digest_pinned(img);
                let trust_zone = if pinned {
                    TrustZone::ThirdParty
                } else {
                    TrustZone::Untrusted
                };
                let mut imeta = HashMap::new();
                if let Some(digest) = img.split("@sha256:").nth(1) {
                    imeta.insert(META_DIGEST.into(), format!("sha256:{digest}"));
                }
                graph.add_node_with_metadata(NodeKind::Image, img, trust_zone, imeta)
            });

            // Services (each is an Image node)
            let service_ids = process_services(job_map.get("services"), &mut graph);

            // Environment — record name as metadata, sets trust boundary marker
            let env_name = job_map
                .get("environment")
                .and_then(extract_environment_name);

            // Create the Step node for this job
            let mut step_meta = HashMap::new();
            step_meta.insert(META_JOB_NAME.into(), job_name.to_string());
            if let Some(ref env) = env_name {
                step_meta.insert("environment_name".into(), env.clone());
            }
            let step_id = graph.add_node_with_metadata(
                NodeKind::Step,
                job_name,
                TrustZone::FirstParty,
                step_meta,
            );

            // CI_JOB_TOKEN always available to every step
            graph.add_edge(step_id, token_id, EdgeKind::HasAccessTo);

            // Link all secrets
            for &sid in global_secrets
                .iter()
                .chain(&job_secrets)
                .chain(&explicit_secrets)
            {
                graph.add_edge(step_id, sid, EdgeKind::HasAccessTo);
            }

            // Link OIDC identities
            for &iid in &oidc_identities {
                graph.add_edge(step_id, iid, EdgeKind::HasAccessTo);
            }

            // UsesImage edges
            if let Some(img_id) = image_id {
                graph.add_edge(step_id, img_id, EdgeKind::UsesImage);
            }
            for &svc_id in &service_ids {
                graph.add_edge(step_id, svc_id, EdgeKind::UsesImage);
            }
        }

        Ok(graph)
    }
}

/// Detect `image:` string from a YAML value — can be a bare string or a mapping with `name:`.
fn extract_image_str(v: &Value) -> Option<String> {
    match v {
        Value::String(s) => Some(s.clone()),
        Value::Mapping(m) => m.get("name").and_then(|n| n.as_str()).map(String::from),
        _ => None,
    }
}

/// Extract environment name from `environment:` value (string or mapping).
fn extract_environment_name(v: &Value) -> Option<String> {
    match v {
        Value::String(s) => Some(s.clone()),
        Value::Mapping(m) => m.get("name").and_then(|n| n.as_str()).map(String::from),
        _ => None,
    }
}

/// Classify a variable name as a credential by checking for common fragments.
fn is_credential_name(name: &str) -> bool {
    let upper = name.to_uppercase();
    CRED_FRAGMENTS.iter().any(|frag| upper.contains(frag))
}

/// Parse `variables:` mapping and emit `Secret` nodes for credential-pattern names.
/// Returns the list of created node IDs.
fn process_variables(vars: Option<&Value>, graph: &mut AuthorityGraph, scope: &str) -> Vec<NodeId> {
    let mut ids = Vec::new();
    let map = match vars.and_then(|v| v.as_mapping()) {
        Some(m) => m,
        None => return ids,
    };
    for (k, _v) in map {
        let name = match k.as_str() {
            Some(s) => s,
            None => continue,
        };
        if is_credential_name(name) {
            let id = graph.add_node(NodeKind::Secret, name, TrustZone::FirstParty);
            ids.push(id);
            let _ = scope; // used for future scoped error messages
        }
    }
    ids
}

/// Parse `secrets:` block and emit one `Secret` node per named secret.
///
/// GitLab CI `secrets:` format:
/// ```yaml
/// secrets:
///   DATABASE_PASSWORD:
///     vault: production/db/password@secret
///   AWS_KEY:
///     aws_secrets_manager:
///       name: my-secret
/// ```
fn process_explicit_secrets(
    secrets: Option<&Value>,
    _scope: &str,
    graph: &mut AuthorityGraph,
) -> Vec<NodeId> {
    let mut ids = Vec::new();
    let map = match secrets.and_then(|v| v.as_mapping()) {
        Some(m) => m,
        None => return ids,
    };
    for (k, _v) in map {
        let name = match k.as_str() {
            Some(s) => s,
            None => continue,
        };
        let id = graph.add_node(NodeKind::Secret, name, TrustZone::FirstParty);
        ids.push(id);
    }
    ids
}

/// Parse `id_tokens:` block and emit one OIDC `Identity` node per token.
///
/// GitLab CI `id_tokens:` format:
/// ```yaml
/// id_tokens:
///   SIGSTORE_ID_TOKEN:
///     aud: sigstore
///   AWS_OIDC_TOKEN:
///     aud: https://sts.amazonaws.com
/// ```
fn process_id_tokens(
    id_tokens: Option<&Value>,
    _scope: &str,
    graph: &mut AuthorityGraph,
) -> Vec<NodeId> {
    let mut ids = Vec::new();
    let map = match id_tokens.and_then(|v| v.as_mapping()) {
        Some(m) => m,
        None => return ids,
    };
    for (k, v) in map {
        let token_name = match k.as_str() {
            Some(s) => s,
            None => continue,
        };
        // Extract audience for labelling
        let aud = v
            .as_mapping()
            .and_then(|m| m.get("aud"))
            .and_then(|a| a.as_str())
            .unwrap_or("unknown");
        let label = format!("{token_name} (aud={aud})");
        let mut meta = HashMap::new();
        meta.insert(META_OIDC.into(), "true".into());
        meta.insert(META_IDENTITY_SCOPE.into(), "broad".into());
        let id =
            graph.add_node_with_metadata(NodeKind::Identity, label, TrustZone::FirstParty, meta);
        ids.push(id);
    }
    ids
}

/// Parse `services:` block and emit `Image` nodes.
fn process_services(services: Option<&Value>, graph: &mut AuthorityGraph) -> Vec<NodeId> {
    let mut ids = Vec::new();
    let list = match services.and_then(|v| v.as_sequence()) {
        Some(s) => s,
        None => return ids,
    };
    for item in list {
        let img_str = match extract_image_str(item) {
            Some(s) => s,
            None => continue,
        };
        let pinned = is_docker_digest_pinned(&img_str);
        let trust_zone = if pinned {
            TrustZone::ThirdParty
        } else {
            TrustZone::Untrusted
        };
        let mut meta = HashMap::new();
        if let Some(digest) = img_str.split("@sha256:").nth(1) {
            meta.insert(META_DIGEST.into(), format!("sha256:{digest}"));
        }
        let id = graph.add_node_with_metadata(NodeKind::Image, &img_str, trust_zone, meta);
        ids.push(id);
    }
    ids
}

/// Check whether a job's `rules:` or `only:` indicates it runs on merge requests.
fn job_has_mr_trigger(job_map: &serde_yaml::Mapping) -> bool {
    // rules: [{if: '$CI_PIPELINE_SOURCE == "merge_request_event"'}]
    if let Some(rules) = job_map.get("rules").and_then(|v| v.as_sequence()) {
        for rule in rules {
            if let Some(if_expr) = rule
                .as_mapping()
                .and_then(|m| m.get("if"))
                .and_then(|v| v.as_str())
            {
                if if_expr.contains("merge_request_event") {
                    return true;
                }
            }
        }
    }
    // only: [merge_requests] or only: {refs: [merge_requests]}
    if let Some(only) = job_map.get("only") {
        if only_has_merge_requests(only) {
            return true;
        }
    }
    false
}

/// Check `only:` value (sequence or mapping) for `merge_requests` entry.
fn only_has_merge_requests(v: &Value) -> bool {
    match v {
        Value::Sequence(seq) => seq
            .iter()
            .any(|item| item.as_str() == Some("merge_requests")),
        Value::Mapping(m) => {
            if let Some(refs) = m.get("refs").and_then(|r| r.as_sequence()) {
                return refs
                    .iter()
                    .any(|item| item.as_str() == Some("merge_requests"));
            }
            false
        }
        _ => false,
    }
}

/// Check top-level `workflow:` rules for MR trigger.
fn has_mr_trigger_in_workflow(wf: &Value) -> bool {
    let rules = match wf
        .as_mapping()
        .and_then(|m| m.get("rules"))
        .and_then(|r| r.as_sequence())
    {
        Some(r) => r,
        None => return false,
    };
    for rule in rules {
        if let Some(if_expr) = rule
            .as_mapping()
            .and_then(|m| m.get("if"))
            .and_then(|v| v.as_str())
        {
            if if_expr.contains("merge_request_event") {
                return true;
            }
        }
    }
    false
}

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

    fn parse(yaml: &str) -> AuthorityGraph {
        let parser = GitlabParser;
        let source = PipelineSource {
            file: ".gitlab-ci.yml".into(),
            repo: None,
            git_ref: None,
            commit_sha: None,
        };
        parser.parse(yaml, &source).unwrap()
    }

    #[test]
    fn ci_job_token_always_present() {
        let yaml = r#"
stages:
  - build

build-job:
  stage: build
  script:
    - make build
"#;
        let graph = parse(yaml);
        let identities: Vec<_> = graph.nodes_of_kind(NodeKind::Identity).collect();
        assert_eq!(identities.len(), 1);
        assert_eq!(identities[0].name, "CI_JOB_TOKEN");
        assert_eq!(
            identities[0]
                .metadata
                .get(META_IMPLICIT)
                .map(String::as_str),
            Some("true")
        );
        assert_eq!(
            identities[0]
                .metadata
                .get(META_IDENTITY_SCOPE)
                .map(String::as_str),
            Some("broad")
        );
    }

    #[test]
    fn global_credential_variable_emits_secret_node() {
        let yaml = r#"
variables:
  APP_VERSION: "1.0"
  DEPLOY_TOKEN: "$CI_DEPLOY_TOKEN"

build-job:
  script:
    - make
"#;
        let graph = parse(yaml);
        let secrets: Vec<_> = graph.nodes_of_kind(NodeKind::Secret).collect();
        assert!(
            secrets.iter().any(|s| s.name == "DEPLOY_TOKEN"),
            "DEPLOY_TOKEN must emit a Secret node, got: {:?}",
            secrets.iter().map(|s| &s.name).collect::<Vec<_>>()
        );
        // Plain config variable must not emit Secret
        assert!(
            !secrets.iter().any(|s| s.name == "APP_VERSION"),
            "APP_VERSION must not emit a Secret node"
        );
    }

    #[test]
    fn floating_image_emits_untrusted_image_node() {
        let yaml = r#"
deploy:
  image: alpine:latest
  script:
    - deploy.sh
"#;
        let graph = parse(yaml);
        let images: Vec<_> = graph.nodes_of_kind(NodeKind::Image).collect();
        assert_eq!(images.len(), 1);
        assert_eq!(images[0].name, "alpine:latest");
        assert_eq!(images[0].trust_zone, TrustZone::Untrusted);
    }

    #[test]
    fn digest_pinned_image_is_third_party() {
        let yaml = r#"
deploy:
  image: "alpine@sha256:a5ac7e51b41094c92402da3b24376905380afc29a5ac7e51b41094c92402da3b"
  script:
    - deploy.sh
"#;
        let graph = parse(yaml);
        let images: Vec<_> = graph.nodes_of_kind(NodeKind::Image).collect();
        assert_eq!(images.len(), 1);
        assert_eq!(images[0].trust_zone, TrustZone::ThirdParty);
    }

    #[test]
    fn id_tokens_emit_oidc_identity_nodes() {
        let yaml = r#"
deploy:
  id_tokens:
    SIGSTORE_ID_TOKEN:
      aud: sigstore
    AWS_OIDC_TOKEN:
      aud: https://sts.amazonaws.com
  script:
    - deploy.sh
"#;
        let graph = parse(yaml);
        let oidc: Vec<_> = graph
            .nodes_of_kind(NodeKind::Identity)
            .filter(|n| n.metadata.get(META_OIDC).map(String::as_str) == Some("true"))
            .collect();
        assert_eq!(
            oidc.len(),
            2,
            "expected 2 OIDC identity nodes, got: {:?}",
            oidc.iter().map(|n| &n.name).collect::<Vec<_>>()
        );
    }

    #[test]
    fn explicit_secrets_emit_secret_nodes() {
        let yaml = r#"
deploy:
  secrets:
    DATABASE_PASSWORD:
      vault: production/db/password@secret
    AWS_KEY:
      aws_secrets_manager:
        name: my-secret
  script:
    - deploy.sh
"#;
        let graph = parse(yaml);
        let secrets: Vec<_> = graph.nodes_of_kind(NodeKind::Secret).collect();
        let names: Vec<_> = secrets.iter().map(|s| s.name.as_str()).collect();
        assert!(names.contains(&"DATABASE_PASSWORD"), "got: {names:?}");
        assert!(names.contains(&"AWS_KEY"), "got: {names:?}");
    }

    #[test]
    fn rules_mr_trigger_sets_meta_trigger() {
        let yaml = r#"
test:
  rules:
    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
  script:
    - run tests
"#;
        let graph = parse(yaml);
        assert_eq!(
            graph.metadata.get(META_TRIGGER).map(String::as_str),
            Some("merge_request"),
            "META_TRIGGER must be set to merge_request"
        );
    }

    #[test]
    fn only_merge_requests_sets_meta_trigger() {
        let yaml = r#"
test:
  only:
    - merge_requests
  script:
    - run tests
"#;
        let graph = parse(yaml);
        assert_eq!(
            graph.metadata.get(META_TRIGGER).map(String::as_str),
            Some("merge_request")
        );
    }

    #[test]
    fn include_marks_graph_partial() {
        let yaml = r#"
include:
  - local: '/templates/.base.yml'

build:
  script:
    - make
"#;
        let graph = parse(yaml);
        assert_eq!(graph.completeness, AuthorityCompleteness::Partial);
    }

    #[test]
    fn extends_marks_graph_partial() {
        let yaml = r#"
.base:
  script:
    - echo base

my-job:
  extends: .base
  stage: build
"#;
        let graph = parse(yaml);
        assert_eq!(graph.completeness, AuthorityCompleteness::Partial);
    }

    #[test]
    fn meta_job_name_set_on_step_nodes() {
        let yaml = r#"
build:
  script:
    - make
deploy:
  script:
    - deploy.sh
"#;
        let graph = parse(yaml);
        let steps: Vec<_> = graph.nodes_of_kind(NodeKind::Step).collect();
        assert_eq!(steps.len(), 2);
        for step in &steps {
            assert!(
                step.metadata.contains_key(META_JOB_NAME),
                "Step '{}' missing META_JOB_NAME",
                step.name
            );
        }
        // Verify job names are correct
        let names: Vec<_> = steps
            .iter()
            .map(|s| s.metadata.get(META_JOB_NAME).unwrap().as_str())
            .collect();
        assert!(names.contains(&"build"), "got: {names:?}");
        assert!(names.contains(&"deploy"), "got: {names:?}");
    }

    #[test]
    fn reserved_keywords_not_parsed_as_jobs() {
        let yaml = r#"
stages:
  - build
  - test

variables:
  MY_VAR: value

image: alpine:latest

build:
  stage: build
  script:
    - make
"#;
        let graph = parse(yaml);
        let steps: Vec<_> = graph.nodes_of_kind(NodeKind::Step).collect();
        assert_eq!(
            steps.len(),
            1,
            "only 'build' should be a Step, got: {:?}",
            steps.iter().map(|s| &s.name).collect::<Vec<_>>()
        );
        assert_eq!(steps[0].name, "build");
    }

    #[test]
    fn services_emit_image_nodes() {
        let yaml = r#"
test:
  services:
    - docker:dind
    - name: postgres:14
  script:
    - run_tests
"#;
        let graph = parse(yaml);
        let images: Vec<_> = graph.nodes_of_kind(NodeKind::Image).collect();
        assert_eq!(
            images.len(),
            2,
            "expected 2 service Image nodes, got: {:?}",
            images.iter().map(|i| &i.name).collect::<Vec<_>>()
        );
    }
}