helm-schema-gen 0.0.6

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

use serde_json::Value;
use serde_yaml::Value as YamlValue;

use crate::merge::merge_schema_list;
use crate::schema_model::{empty_schema, is_empty_schema};
use crate::schema_node::SchemaNode;

pub(crate) fn apply_values_default_sources(
    doc: &mut YamlValue,
    sources: &BTreeSet<helm_schema_core::ValuesDefaultSource>,
) {
    let mut by_target: BTreeMap<&str, Vec<&helm_schema_core::ValuesDefaultSource>> =
        BTreeMap::new();
    for source in sources {
        by_target
            .entry(&source.target_path)
            .or_default()
            .push(source);
    }
    for sources in by_target.values() {
        // Multiple mutations of one target are order-sensitive. The signal
        // bundle intentionally carries no guessed lexical order, so only a
        // unique source is safe to apply.
        let [source] = sources.as_slice() else {
            continue;
        };
        let Some(defaults) = yaml_value_at_path(doc, &source.source_path).cloned() else {
            continue;
        };
        let target_segments = crate::split_value_path(&source.target_path);
        let Some(target) = yaml_value_at_segments_mut(doc, &target_segments) else {
            continue;
        };
        merge_missing_yaml_values(target, defaults);
    }
}

/// Copy each unique root-merge default from `source_doc` into `target_doc`
/// at its target path, creating intermediate mappings: the
/// absence-semantics document needs these render-time defaults even when
/// nothing else declares the subtree.
pub(crate) fn copy_values_default_sources(
    target_doc: &mut YamlValue,
    source_doc: &YamlValue,
    sources: &BTreeSet<helm_schema_core::ValuesDefaultSource>,
) {
    let mut by_target: BTreeMap<&str, Vec<&helm_schema_core::ValuesDefaultSource>> =
        BTreeMap::new();
    for source in sources {
        by_target
            .entry(&source.target_path)
            .or_default()
            .push(source);
    }
    for sources in by_target.values() {
        // Only a unique source per target is safe to apply; see
        // `apply_values_default_sources`.
        let [source] = sources.as_slice() else {
            continue;
        };
        let Some(defaults) = yaml_value_at_path(source_doc, &source.source_path).cloned() else {
            continue;
        };
        if !matches!(target_doc, YamlValue::Mapping(_)) {
            *target_doc = YamlValue::Mapping(serde_yaml::Mapping::default());
        }
        let target_segments = crate::split_value_path(&source.target_path);
        let mut current = &mut *target_doc;
        for segment in &target_segments {
            let YamlValue::Mapping(mapping) = current else {
                break;
            };
            let key = YamlValue::String(segment.clone());
            current = mapping
                .entry(key)
                .or_insert_with(|| YamlValue::Mapping(serde_yaml::Mapping::default()));
        }
        merge_missing_yaml_values(current, defaults);
    }
}

fn yaml_value_at_segments_mut<'a>(
    doc: &'a mut YamlValue,
    path_segments: &[String],
) -> Option<&'a mut YamlValue> {
    let mut current = doc;
    for segment in path_segments {
        let YamlValue::Mapping(mapping) = current else {
            return None;
        };
        current = mapping.get_mut(YamlValue::String(segment.clone()))?;
    }
    Some(current)
}

fn merge_missing_yaml_values(target: &mut YamlValue, defaults: YamlValue) {
    let (YamlValue::Mapping(target), YamlValue::Mapping(defaults)) = (target, defaults) else {
        return;
    };
    for (key, default) in defaults {
        if let Some(existing) = target.get_mut(&key) {
            merge_missing_yaml_values(existing, default);
        } else {
            target.insert(key, default);
        }
    }
}

pub(crate) struct ValuesYamlPathInfo {
    pub(crate) schema: Value,
    pub(crate) declared_defaults: Vec<Value>,
    pub(crate) is_explicit_null: bool,
    pub(crate) is_empty_string: bool,
    pub(crate) is_empty_map: bool,
    pub(crate) is_mapping: bool,
}

#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
pub(crate) struct ValuesYamlPathFacts {
    pub(crate) has_no_schema_evidence: bool,
    pub(crate) is_explicit_null: bool,
    pub(crate) is_empty_string: bool,
    pub(crate) is_empty_map: bool,
    pub(crate) is_mapping: bool,
    pub(crate) has_dependency_default: bool,
}

impl ValuesYamlPathFacts {
    pub(crate) fn absent() -> Self {
        Self {
            has_no_schema_evidence: true,
            ..Self::default()
        }
    }
}

impl ValuesYamlPathInfo {
    pub(crate) fn facts(&self) -> ValuesYamlPathFacts {
        ValuesYamlPathFacts {
            has_no_schema_evidence: is_empty_schema(&self.schema),
            is_explicit_null: self.is_explicit_null,
            is_empty_string: self.is_empty_string,
            is_empty_map: self.is_empty_map,
            is_mapping: self.is_mapping,
            has_dependency_default: false,
        }
    }
}

#[tracing::instrument(skip_all)]
pub(crate) fn build_values_yaml_path_info(
    values_yaml_doc: &YamlValue,
    referenced_value_paths: &BTreeSet<String>,
    pruned_parent_value_paths: &BTreeSet<String>,
    unconditionally_omitted_value_paths: &BTreeSet<String>,
    direct_ranged_value_paths: &BTreeSet<String>,
) -> BTreeMap<String, ValuesYamlPathInfo> {
    referenced_value_paths
        .iter()
        .filter_map(|path| {
            let segments = crate::split_value_path(path);
            lookup_values_yaml_path_info(values_yaml_doc, &segments)
                .map(|mut path_info| {
                    if pruned_parent_value_paths.contains(path) {
                        prune_referenced_descendant_schemas(
                            &mut path_info.schema,
                            path,
                            referenced_value_paths,
                        );
                    } else {
                        // Even under fragment parents (whose subtree
                        // schemas otherwise stay whole), a directly
                        // ranged member's declared shape must yield to
                        // its own resolution: the runtime iterable
                        // domain is wider than any declared default.
                        prune_referenced_descendant_schemas(
                            &mut path_info.schema,
                            path,
                            direct_ranged_value_paths,
                        );
                        // A member removed before every provider sink has no
                        // parent-level input contract. Its own path evidence
                        // decides whether the declared default remains
                        // meaningful.
                        prune_referenced_descendant_schemas(
                            &mut path_info.schema,
                            path,
                            unconditionally_omitted_value_paths,
                        );
                    }
                    path_info
                })
                .map(|path_info| (path.clone(), path_info))
        })
        .collect()
}

fn lookup_values_yaml_path_info(
    doc: &YamlValue,
    path_segments: &[String],
) -> Option<ValuesYamlPathInfo> {
    if path_segments.is_empty() {
        return None;
    }

    let values = lookup_values_yaml_values(doc, path_segments)?;
    if values.is_empty() {
        return None;
    }

    let schema = merge_schema_list(values.iter().copied().map(schema_from_yaml_value).collect());
    let declared_defaults = values
        .iter()
        .filter_map(|value| serde_json::to_value(value).ok())
        .collect();
    let is_explicit_null = matches!(values.as_slice(), [YamlValue::Null]);
    let is_empty_string = values
        .iter()
        .any(|value| matches!(value, YamlValue::String(value) if value.is_empty()));
    let is_empty_map = values
        .iter()
        .all(|value| matches!(value, YamlValue::Mapping(map) if map.is_empty()));
    let is_mapping = values
        .iter()
        .all(|value| matches!(value, YamlValue::Mapping(_)));
    Some(ValuesYamlPathInfo {
        schema,
        declared_defaults,
        is_explicit_null,
        is_empty_string,
        is_empty_map,
        is_mapping,
    })
}

pub(crate) fn yaml_value_at_segments<'a>(
    doc: &'a YamlValue,
    path_segments: &[String],
) -> Option<&'a YamlValue> {
    let mut current = doc;
    for segment in path_segments {
        let YamlValue::Mapping(mapping) = current else {
            return None;
        };
        current = mapping.get(YamlValue::String(segment.clone()))?;
    }
    Some(current)
}

pub(crate) fn yaml_value_at_path<'a>(
    doc: &'a YamlValue,
    value_path: &str,
) -> Option<&'a YamlValue> {
    yaml_value_at_segments(doc, &crate::split_value_path(value_path))
}

pub(crate) fn remove_values_paths(doc: &mut YamlValue, paths: &BTreeSet<String>) {
    for path in paths {
        remove_value_at_segments(doc, &crate::split_value_path(path));
    }
}

fn remove_value_at_segments(doc: &mut YamlValue, path: &[String]) {
    let Some((last, parents)) = path.split_last() else {
        return;
    };
    let mut current = doc;
    for segment in parents {
        let YamlValue::Mapping(mapping) = current else {
            return;
        };
        let Some(next) = mapping.get_mut(YamlValue::String(segment.clone())) else {
            return;
        };
        current = next;
    }
    let YamlValue::Mapping(mapping) = current else {
        return;
    };
    mapping.remove(YamlValue::String(last.clone()));
}

fn lookup_values_yaml_values<'a>(
    doc: &'a YamlValue,
    path_segments: &[String],
) -> Option<Vec<&'a YamlValue>> {
    if path_segments.is_empty() {
        return Some(vec![doc]);
    }

    let (head, tail) = path_segments.split_first()?;
    let head = head.as_str();

    match doc {
        YamlValue::Mapping(map) => {
            let key = YamlValue::String(head.to_string());
            let next = map.get(&key)?;
            lookup_values_yaml_values(next, tail)
        }
        YamlValue::Sequence(sequence) if head == "*" => {
            let mut out: Vec<&'a YamlValue> = Vec::new();
            for item in sequence {
                if let Some(mut child) = lookup_values_yaml_values(item, tail) {
                    out.append(&mut child);
                }
            }
            if out.is_empty() { None } else { Some(out) }
        }
        _ => None,
    }
}

fn prune_referenced_descendant_schemas(
    schema: &mut Value,
    value_path: &str,
    referenced_value_paths: &BTreeSet<String>,
) {
    let descendant_prefix = format!("{value_path}.");
    let mut relative_paths_to_prune = BTreeSet::new();
    for descendant in referenced_value_paths {
        let Some(relative_path) = descendant.strip_prefix(&descendant_prefix) else {
            continue;
        };
        let relative_segments = crate::split_value_path(relative_path);
        if relative_segments.is_empty() {
            continue;
        }
        relative_paths_to_prune.insert(shortest_referenced_relative_path(
            value_path,
            &relative_segments,
            referenced_value_paths,
        ));
    }

    for relative_segments in relative_paths_to_prune {
        let relative_segments: Vec<&str> = relative_segments
            .iter()
            .map(std::string::String::as_str)
            .collect();
        prune_schema_at_relative_path(schema, &relative_segments);
    }
}

fn shortest_referenced_relative_path(
    value_path: &str,
    relative_segments: &[String],
    referenced_value_paths: &BTreeSet<String>,
) -> Vec<String> {
    let mut prefix = Vec::new();
    for segment in relative_segments {
        prefix.push(segment.clone());
        let mut candidate_segments = crate::split_value_path(value_path);
        candidate_segments.extend(prefix.iter().cloned());
        let candidate_path = helm_schema_core::join_value_path(candidate_segments);
        if referenced_value_paths.contains(&candidate_path) {
            return prefix;
        }
    }
    relative_segments.to_vec()
}

fn prune_schema_at_relative_path(schema: &mut Value, relative_segments: &[&str]) {
    let Some((head, tail)) = relative_segments.split_first() else {
        return;
    };
    let Value::Object(object) = schema else {
        return;
    };

    if *head == "*" {
        if let Some(items) = object.get_mut("items") {
            if tail.is_empty() {
                *items = empty_schema();
            } else {
                prune_schema_at_relative_path(items, tail);
            }
        }
        return;
    }

    let Some(properties) = object.get_mut("properties").and_then(Value::as_object_mut) else {
        return;
    };
    if tail.is_empty() {
        properties.remove(*head);
        return;
    }

    if let Some(child) = properties.get_mut(*head) {
        prune_schema_at_relative_path(child, tail);
    }
}

fn schema_from_yaml_value(value: &YamlValue) -> Value {
    schema_node_from_yaml_value_with_skips(value, &[], &BTreeSet::new())
        .unwrap_or_else(SchemaNode::empty)
        .into_value()
}

pub(crate) fn schema_node_from_yaml_value_with_skips(
    value: &YamlValue,
    current_path: &[String],
    skip_paths: &BTreeSet<Vec<String>>,
) -> Option<SchemaNode> {
    if skip_paths.contains(current_path) {
        return None;
    }

    match value {
        YamlValue::Null | YamlValue::Tagged(_) => Some(SchemaNode::empty()),
        YamlValue::Bool(_) => Some(SchemaNode::type_named("boolean")),
        YamlValue::Number(number) => {
            let schema = if number.as_i64().is_some() || number.as_u64().is_some() {
                SchemaNode::type_named("integer")
            } else {
                SchemaNode::type_named("number")
            };
            Some(schema)
        }
        YamlValue::String(_) => Some(SchemaNode::type_named("string")),
        YamlValue::Sequence(sequence) => {
            let items = if sequence.is_empty() {
                empty_schema()
            } else {
                merge_schema_list(
                    sequence
                        .iter()
                        .filter_map(|item| {
                            schema_node_from_yaml_value_with_skips(item, current_path, skip_paths)
                        })
                        .map(SchemaNode::into_value)
                        .collect(),
                )
            };
            Some(SchemaNode::array().items(SchemaNode::foreign(items)))
        }
        YamlValue::Mapping(mapping) => {
            if mapping.is_empty() {
                return Some(SchemaNode::unknown_object());
            }
            // Declared defaults DOCUMENT keys, they do not bound them: a
            // chart's config mappings are routinely extended by users and
            // serialized wholesale, so the declared shape must stay open.
            // Closure is only ever justified by exhaustive structural
            // evidence (provider schemas, exact-empty off-states).
            let mut schema = SchemaNode::unknown_object();
            let mut inserted = false;
            for (key, value) in mapping {
                let Some(key) = key.as_str() else {
                    continue;
                };
                let child_path = child_value_path(current_path, key);
                let child_schema = if skip_paths.contains(&child_path) {
                    SchemaNode::empty()
                } else {
                    schema_node_from_yaml_value_with_skips(value, &child_path, skip_paths)?
                };
                inserted = true;
                schema = schema.property(key.to_string(), child_schema);
            }
            inserted.then_some(schema)
        }
    }
}

pub(crate) fn child_value_path(parent: &[String], child: &str) -> Vec<String> {
    let mut path = parent.to_vec();
    path.push(child.to_string());
    path
}