use crate::charybdis::entities::Entity;
use crate::database::EntityRepository;
use anyhow::{Result, anyhow};
use serde::{Deserialize, Serialize};
use serde_json::Value;
use std::collections::HashMap;
use std::sync::Arc;
use tracing::warn;

/// Field mapper handles mapping between entity fields and external tool fields
pub struct FieldMapper {
    mappings: HashMap<String, FieldMapping>,
    repository: Option<Arc<EntityRepository>>,
}

/// Field mapping types
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(untagged)]
pub enum FieldMapping {
    /// Complex mapping with entity resolution (must come first to match objects with "from" key)
    Complex(ComplexMapping),

    /// Static value wrapper (object with "value" key)
    /// Example: {"value": "Web Application"}, {"value": true}, {"value": 123}
    StaticWrapper(StaticValue),

    /// Direct field access using dot notation (plain string)
    /// Example: "metadata.name" accesses entity.metadata.name
    Direct(String),
}

/// Wrapper for static values to distinguish from field paths
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct StaticValue {
    pub value: Value,
}

/// Complex field mapping configuration
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ComplexMapping {
    /// Source field path
    pub from: String,

    /// Optional: Resolve entity reference
    #[serde(skip_serializing_if = "Option::is_none")]
    pub resolve_entity: Option<String>,

    /// Optional: Find linked entity of this kind
    #[serde(skip_serializing_if = "Option::is_none")]
    pub lookup_entity: Option<String>,

    /// Optional: Extract field from resolved entity
    #[serde(skip_serializing_if = "Option::is_none")]
    pub extract: Option<String>,

    /// Optional: Resolve array of entity IDs
    #[serde(default)]
    pub resolve_array: bool,

    /// Optional: Transform function
    #[serde(skip_serializing_if = "Option::is_none")]
    pub transform: Option<String>,
}

impl FieldMapper {
    /// Create a new field mapper from configuration
    /// Config format: { "target_field": "source.field" or complex mapping }
    pub fn new(config: HashMap<String, Value>) -> Result<Self> {
        let mut mappings = HashMap::new();

        for (field_name, mapping_value) in config {
            let mapping = Self::parse_mapping(mapping_value)?;
            mappings.insert(field_name, mapping);
        }

        Ok(Self {
            mappings,
            repository: None,
        })
    }

    /// Set the entity repository (required for entity resolution)
    pub fn with_repository(mut self, repository: Arc<EntityRepository>) -> Self {
        self.repository = Some(repository);
        self
    }

    /// Parse a mapping value from config
    fn parse_mapping(value: Value) -> Result<FieldMapping> {
        // Use serde untagged deserialization
        // Order matters: Complex (with "from"), StaticWrapper (with "value"), Direct (string)
        serde_json::from_value(value).map_err(|e| anyhow!("Failed to parse field mapping: {}", e))
    }

    /// Map a single field from source entity (async for entity resolution)
    pub async fn map(&self, field_name: &str, entity: &Entity) -> Result<Value> {
        let mapping = self
            .mappings
            .get(field_name)
            .ok_or_else(|| anyhow!("No mapping configured for field: {}", field_name))?;

        match mapping {
            FieldMapping::Direct(path) => self.get_field_by_path(entity, path),

            FieldMapping::StaticWrapper(static_val) => Ok(static_val.value.clone()),

            FieldMapping::Complex(complex) => self.map_complex(complex, entity).await,
        }
    }

    /// Handle complex field mapping with entity resolution
    async fn map_complex(&self, mapping: &ComplexMapping, entity: &Entity) -> Result<Value> {
        // Get source field value
        let source_value = self.get_field_by_path(entity, &mapping.from)?;

        // If no entity resolution needed, just return (possibly transformed) value
        if mapping.resolve_entity.is_none() && !mapping.resolve_array {
            return Ok(source_value);
        }

        // Entity resolution required - need repository
        let repository = self
            .repository
            .as_ref()
            .ok_or_else(|| anyhow!("Entity resolution requires repository"))?;

        // Handle array resolution
        if mapping.resolve_array {
            return self.resolve_array(source_value, mapping, repository).await;
        }

        // Handle single entity resolution
        if let Some(resolve_kind) = &mapping.resolve_entity {
            return self
                .resolve_entity(source_value, resolve_kind, mapping, repository)
                .await;
        }

        Ok(source_value)
    }

    /// Resolve a single entity reference
    async fn resolve_entity(
        &self,
        entity_id: Value,
        expected_kind: &str,
        mapping: &ComplexMapping,
        repository: &EntityRepository,
    ) -> Result<Value> {
        let id_str = entity_id
            .as_str()
            .ok_or_else(|| anyhow!("Entity ID must be a string"))?;

        // Resolve the entity
        let resolved = repository
            .get_by_id(id_str)
            .await?
            .ok_or_else(|| anyhow!("Entity not found: {}", id_str))?;

        // Validate kind if specified
        if resolved.kind != expected_kind {
            return Err(anyhow!(
                "Expected entity kind {}, got {}",
                expected_kind,
                resolved.kind
            ));
        }

        // If we need to lookup a linked entity
        if let Some(lookup_kind) = &mapping.lookup_entity {
            let linked = self
                .find_linked_entity(&resolved.id, lookup_kind, repository)
                .await?;

            // Extract field from linked entity
            if let Some(extract_path) = &mapping.extract {
                return self.get_field_by_path(&linked, extract_path);
            }

            return entity_to_json(&linked);
        }

        // Extract field from resolved entity
        if let Some(extract_path) = &mapping.extract {
            return self.get_field_by_path(&resolved, extract_path);
        }

        // Return entire resolved entity
        entity_to_json(&resolved)
    }

    /// Resolve an array of entity references
    async fn resolve_array(
        &self,
        entity_ids: Value,
        mapping: &ComplexMapping,
        repository: &EntityRepository,
    ) -> Result<Value> {
        let ids_array = entity_ids
            .as_array()
            .ok_or_else(|| anyhow!("Expected array of entity IDs"))?;

        let mut results = Vec::new();

        for id_value in ids_array {
            let resolve_kind = mapping
                .resolve_entity
                .as_ref()
                .ok_or_else(|| anyhow!("resolve_entity required for array resolution"))?;

            match self
                .resolve_entity(id_value.clone(), resolve_kind, mapping, repository)
                .await
            {
                Ok(value) => results.push(value),
                Err(e) => {
                    warn!("Failed to resolve entity in array: {}", e);
                    // Continue with other entities
                }
            }
        }

        Ok(Value::Array(results))
    }

    /// Find an entity linked to a source entity
    async fn find_linked_entity(
        &self,
        source_id: &str,
        target_kind: &str,
        repository: &EntityRepository,
    ) -> Result<Entity> {
        let entities = repository.list_by_kind(target_kind).await?;

        // Find entity with linked_entity_id matching source_id
        for entity in entities {
            let linked_id = self
                .get_field_by_path(&entity, "metadata.linked_entity_id")
                .ok()
                .and_then(|v| v.as_str().map(String::from));

            if linked_id.as_deref() == Some(source_id) {
                return Ok(entity);
            }
        }

        Err(anyhow!(
            "No {} entity found linked to {}",
            target_kind,
            source_id
        ))
    }

    /// Get field value from entity using dot notation path
    /// Example: "metadata.name" → entity.metadata.name
    fn get_field_by_path(&self, entity: &Entity, path: &str) -> Result<Value> {
        // Convert entity to JSON for easy path traversal
        let entity_json = entity_to_json(entity)?;

        // Split path and traverse JSON
        let parts: Vec<&str> = path.split('.').collect();
        let mut current = &entity_json;

        for part in parts {
            current = current
                .get(part)
                .ok_or_else(|| anyhow!("Field not found in entity: {}", path))?;
        }

        Ok(current.clone())
    }

    /// Map all configured fields from entity to target format
    /// Returns HashMap of field_name → mapped_value
    pub async fn map_all(&self, entity: &Entity) -> Result<HashMap<String, Value>> {
        let mut result = HashMap::new();

        for (field_name, _) in &self.mappings {
            match self.map(field_name, entity).await {
                Ok(value) => {
                    result.insert(field_name.clone(), value);
                }
                Err(e) => {
                    // Log warning but don't fail entire mapping
                    warn!("Failed to map field {}: {}", field_name, e);
                }
            }
        }

        Ok(result)
    }

    /// Check if a field is mapped
    pub fn has_mapping(&self, field_name: &str) -> bool {
        self.mappings.contains_key(field_name)
    }
}

/// Helper function to convert Entity to JSON Value
/// Works around prost_types::Timestamp not implementing serde traits
fn entity_to_json(entity: &Entity) -> Result<Value> {
    use crate::charybdis::entities::entity;
    use serde_json::json;

    // Manual conversion to avoid prost_types::Timestamp serde issues
    let mut entity_obj = serde_json::Map::new();

    entity_obj.insert("id".to_string(), json!(&entity.id));
    entity_obj.insert("kind".to_string(), json!(&entity.kind));

    // Add metadata if present - extract fields based on metadata type
    if let Some(ref metadata) = entity.metadata {
        let mut metadata_obj = serde_json::Map::new();

        match metadata {
            entity::Metadata::ServiceMetadata(m) => {
                metadata_obj.insert("name".to_string(), json!(&m.name));
                if !m.namespace.is_empty() {
                    metadata_obj.insert("namespace".to_string(), json!(&m.namespace));
                }
                if !m.description.is_empty() {
                    metadata_obj.insert("description".to_string(), json!(&m.description));
                }
                // ServiceMetadata labels is repeated string (Vec<String>)
                if !m.labels.is_empty() {
                    metadata_obj.insert("labels".to_string(), json!(&m.labels));
                }
                if !m.tags.is_empty() {
                    metadata_obj.insert("tags".to_string(), json!(&m.tags));
                }
            }
            entity::Metadata::SystemMetadata(m) => {
                metadata_obj.insert("name".to_string(), json!(&m.name));
                if !m.namespace.is_empty() {
                    metadata_obj.insert("namespace".to_string(), json!(&m.namespace));
                }
                if !m.description.is_empty() {
                    metadata_obj.insert("description".to_string(), json!(&m.description));
                }
                if !m.labels.is_empty() {
                    metadata_obj.insert("labels".to_string(), json!(&m.labels));
                }
                if !m.tags.is_empty() {
                    metadata_obj.insert("tags".to_string(), json!(&m.tags));
                }
            }
            entity::Metadata::ComponentMetadata(m) => {
                metadata_obj.insert("name".to_string(), json!(&m.name));
                if !m.namespace.is_empty() {
                    metadata_obj.insert("namespace".to_string(), json!(&m.namespace));
                }
                if !m.description.is_empty() {
                    metadata_obj.insert("description".to_string(), json!(&m.description));
                }
                if !m.labels.is_empty() {
                    metadata_obj.insert("labels".to_string(), json!(&m.labels));
                }
                if !m.tags.is_empty() {
                    metadata_obj.insert("tags".to_string(), json!(&m.tags));
                }
            }
            entity::Metadata::ApiMetadata(m) => {
                metadata_obj.insert("name".to_string(), json!(&m.name));
                if !m.namespace.is_empty() {
                    metadata_obj.insert("namespace".to_string(), json!(&m.namespace));
                }
                if !m.description.is_empty() {
                    metadata_obj.insert("description".to_string(), json!(&m.description));
                }
                if !m.labels.is_empty() {
                    metadata_obj.insert("labels".to_string(), json!(&m.labels));
                }
                if !m.tags.is_empty() {
                    metadata_obj.insert("tags".to_string(), json!(&m.tags));
                }
            }
            entity::Metadata::UserMetadata(m) => {
                metadata_obj.insert("name".to_string(), json!(&m.name));
                if !m.namespace.is_empty() {
                    metadata_obj.insert("namespace".to_string(), json!(&m.namespace));
                }
                if !m.description.is_empty() {
                    metadata_obj.insert("description".to_string(), json!(&m.description));
                }
                if !m.labels.is_empty() {
                    metadata_obj.insert("labels".to_string(), json!(&m.labels));
                }
                if !m.tags.is_empty() {
                    metadata_obj.insert("tags".to_string(), json!(&m.tags));
                }
            }
            entity::Metadata::GroupMetadata(m) => {
                metadata_obj.insert("name".to_string(), json!(&m.name));
                if !m.namespace.is_empty() {
                    metadata_obj.insert("namespace".to_string(), json!(&m.namespace));
                }
                if !m.description.is_empty() {
                    metadata_obj.insert("description".to_string(), json!(&m.description));
                }
                if !m.labels.is_empty() {
                    metadata_obj.insert("labels".to_string(), json!(&m.labels));
                }
                if !m.tags.is_empty() {
                    metadata_obj.insert("tags".to_string(), json!(&m.tags));
                }
            }
            entity::Metadata::DomainMetadata(m) => {
                metadata_obj.insert("name".to_string(), json!(&m.name));
                if !m.namespace.is_empty() {
                    metadata_obj.insert("namespace".to_string(), json!(&m.namespace));
                }
                if !m.description.is_empty() {
                    metadata_obj.insert("description".to_string(), json!(&m.description));
                }
                if !m.labels.is_empty() {
                    metadata_obj.insert("labels".to_string(), json!(&m.labels));
                }
                if !m.tags.is_empty() {
                    metadata_obj.insert("tags".to_string(), json!(&m.tags));
                }
            }
            entity::Metadata::ResourceMetadata(m) => {
                metadata_obj.insert("name".to_string(), json!(&m.name));
                if !m.namespace.is_empty() {
                    metadata_obj.insert("namespace".to_string(), json!(&m.namespace));
                }
                if !m.description.is_empty() {
                    metadata_obj.insert("description".to_string(), json!(&m.description));
                }
                if !m.labels.is_empty() {
                    metadata_obj.insert("labels".to_string(), json!(&m.labels));
                }
                if !m.tags.is_empty() {
                    metadata_obj.insert("tags".to_string(), json!(&m.tags));
                }
            }
            entity::Metadata::DefectdojoMetadata(_) => {
                // Plugin type — skip for now
            }
            entity::Metadata::KeycloakMetadata(_) => {
                // Plugin metadata type — skip
            }
            entity::Metadata::DependencytrackMetadata(_) => {
                // Plugin metadata type — skip
            }
            entity::Metadata::FindingMetadata(m) => {
                metadata_obj.insert("name".to_string(), json!(&m.title));
                if !m.description.is_empty() {
                    metadata_obj.insert("description".to_string(), json!(&m.description));
                }
            }
        }

        entity_obj.insert("metadata".to_string(), Value::Object(metadata_obj));
    }

    // Add spec if present - extract fields based on spec type
    if let Some(ref spec) = entity.spec {
        let mut spec_obj = serde_json::Map::new();

        match spec {
            entity::Spec::ServiceSpec(s) => {
                if !s.r#type.is_empty() {
                    spec_obj.insert("type".to_string(), json!(&s.r#type));
                }
                if !s.lifecycle.is_empty() {
                    spec_obj.insert("lifecycle".to_string(), json!(&s.lifecycle));
                }
                if !s.owner.is_empty() {
                    spec_obj.insert("owner".to_string(), json!(&s.owner));
                }
                if !s.system.is_empty() {
                    spec_obj.insert("system".to_string(), json!(&s.system));
                }
                if !s.subcomponent_of.is_empty() {
                    spec_obj.insert("subcomponent_of".to_string(), json!(&s.subcomponent_of));
                }
                if !s.depends_on.is_empty() {
                    spec_obj.insert("depends_on".to_string(), json!(&s.depends_on));
                }
                if !s.consumes_apis.is_empty() {
                    spec_obj.insert("consumes_apis".to_string(), json!(&s.consumes_apis));
                }
                if !s.provides_apis.is_empty() {
                    spec_obj.insert("provides_apis".to_string(), json!(&s.provides_apis));
                }
            }
            entity::Spec::SystemSpec(s) => {
                if !s.owner.is_empty() {
                    spec_obj.insert("owner".to_string(), json!(&s.owner));
                }
                if !s.domain.is_empty() {
                    spec_obj.insert("domain".to_string(), json!(&s.domain));
                }
            }
            entity::Spec::ComponentSpec(s) => {
                if !s.r#type.is_empty() {
                    spec_obj.insert("type".to_string(), json!(&s.r#type));
                }
                if !s.lifecycle.is_empty() {
                    spec_obj.insert("lifecycle".to_string(), json!(&s.lifecycle));
                }
                if !s.owner.is_empty() {
                    spec_obj.insert("owner".to_string(), json!(&s.owner));
                }
                if !s.system.is_empty() {
                    spec_obj.insert("system".to_string(), json!(&s.system));
                }
                if !s.subcomponent_of.is_empty() {
                    spec_obj.insert("subcomponent_of".to_string(), json!(&s.subcomponent_of));
                }
                if !s.depends_on.is_empty() {
                    spec_obj.insert("depends_on".to_string(), json!(&s.depends_on));
                }
                if !s.provides_apis.is_empty() {
                    spec_obj.insert("provides_apis".to_string(), json!(&s.provides_apis));
                }
                if !s.consumes_apis.is_empty() {
                    spec_obj.insert("consumes_apis".to_string(), json!(&s.consumes_apis));
                }
            }
            entity::Spec::ApiSpec(s) => {
                if !s.r#type.is_empty() {
                    spec_obj.insert("type".to_string(), json!(&s.r#type));
                }
                if !s.lifecycle.is_empty() {
                    spec_obj.insert("lifecycle".to_string(), json!(&s.lifecycle));
                }
                if !s.owner.is_empty() {
                    spec_obj.insert("owner".to_string(), json!(&s.owner));
                }
                if !s.system.is_empty() {
                    spec_obj.insert("system".to_string(), json!(&s.system));
                }
                if !s.definition.is_empty() {
                    spec_obj.insert("definition".to_string(), json!(&s.definition));
                }
            }
            entity::Spec::UserSpec(s) => {
                if let Some(profile) = &s.profile {
                    let mut profile_obj = serde_json::Map::new();
                    if !profile.display_name.is_empty() {
                        profile_obj.insert("display_name".to_string(), json!(&profile.display_name));
                    }
                    if !profile.email.is_empty() {
                        profile_obj.insert("email".to_string(), json!(&profile.email));
                    }
                    if !profile.picture.is_empty() {
                        profile_obj.insert("picture".to_string(), json!(&profile.picture));
                    }
                    if !profile_obj.is_empty() {
                        spec_obj.insert("profile".to_string(), Value::Object(profile_obj));
                    }
                }
                if !s.member_of.is_empty() {
                    spec_obj.insert("member_of".to_string(), json!(&s.member_of));
                }
            }
            entity::Spec::GroupSpec(s) => {
                if !s.r#type.is_empty() {
                    spec_obj.insert("type".to_string(), json!(&s.r#type));
                }
                if let Some(profile) = &s.profile {
                    let mut profile_obj = serde_json::Map::new();
                    if !profile.display_name.is_empty() {
                        profile_obj.insert("display_name".to_string(), json!(&profile.display_name));
                    }
                    if !profile.email.is_empty() {
                        profile_obj.insert("email".to_string(), json!(&profile.email));
                    }
                    if !profile.picture.is_empty() {
                        profile_obj.insert("picture".to_string(), json!(&profile.picture));
                    }
                    if !profile_obj.is_empty() {
                        spec_obj.insert("profile".to_string(), Value::Object(profile_obj));
                    }
                }
                if !s.parent.is_empty() {
                    spec_obj.insert("parent".to_string(), json!(&s.parent));
                }
                if !s.children.is_empty() {
                    spec_obj.insert("children".to_string(), json!(&s.children));
                }
                if !s.members.is_empty() {
                    spec_obj.insert("members".to_string(), json!(&s.members));
                }
            }
            entity::Spec::DomainSpec(s) => {
                if !s.owner.is_empty() {
                    spec_obj.insert("owner".to_string(), json!(&s.owner));
                }
            }
            entity::Spec::ResourceSpec(s) => {
                if !s.r#type.is_empty() {
                    spec_obj.insert("type".to_string(), json!(&s.r#type));
                }
                if !s.owner.is_empty() {
                    spec_obj.insert("owner".to_string(), json!(&s.owner));
                }
                if !s.system.is_empty() {
                    spec_obj.insert("system".to_string(), json!(&s.system));
                }
                if !s.depends_on.is_empty() {
                    spec_obj.insert("depends_on".to_string(), json!(&s.depends_on));
                }
            }
            entity::Spec::DefectdojoSpec(_) => {
                // Plugin type — skip for now
            }
            entity::Spec::KeycloakSpec(_) => {
                // Plugin spec type — skip
            }
            entity::Spec::DependencytrackSpec(_) => {
                // Plugin spec type — skip
            }
            entity::Spec::FindingSpec(s) => {
                spec_obj.insert("component_ref".to_string(), json!(&s.component_ref));
                spec_obj.insert("lifecycle".to_string(), json!(&s.lifecycle));
                spec_obj.insert("scanner".to_string(), json!(&s.scanner));
                spec_obj.insert("rule_id".to_string(), json!(&s.rule_id));
            }
        }

        entity_obj.insert("spec".to_string(), Value::Object(spec_obj));
    }

    // Add annotations if present
    if !entity.annotations.is_empty() {
        entity_obj.insert("annotations".to_string(), json!(&entity.annotations));
    }

    Ok(Value::Object(entity_obj))
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::charybdis::core::ComponentMetadata;
    use crate::charybdis::entities::entity;
    use serde_json::json;

    fn create_test_entity(id: &str, kind: &str) -> Entity {
        Entity {
            id: id.to_string(),
            kind: kind.to_string(),
            metadata: Some(entity::Metadata::ComponentMetadata(ComponentMetadata {
                name: "test-component".to_string(),
                description: "Test description".to_string(),
                ..Default::default()
            })),
            spec: None,
            annotations: Default::default(),
            created_at: None,
            updated_at: None,
        }
    }

    #[tokio::test]
    async fn test_direct_field_mapping() {
        let config = HashMap::from([
            ("name".to_string(), json!("metadata.name")),
            ("description".to_string(), json!("metadata.description")),
        ]);

        let mapper = FieldMapper::new(config).unwrap();
        let entity = create_test_entity("test-123", "Component");

        let name = mapper.map("name", &entity).await.unwrap();
        assert_eq!(name, json!("test-component"));

        let desc = mapper.map("description", &entity).await.unwrap();
        assert_eq!(desc, json!("Test description"));
    }

    #[tokio::test]
    async fn test_static_field_mapping() {
        let config = HashMap::from([
            (
                "product_type".to_string(),
                json!({"value": "Web Application"}),
            ),
            ("is_active".to_string(), json!({"value": true})),
            ("priority".to_string(), json!({"value": 100})),
        ]);

        let mapper = FieldMapper::new(config).unwrap();
        let entity = create_test_entity("test-123", "Component");

        assert_eq!(
            mapper.map("product_type", &entity).await.unwrap(),
            json!("Web Application")
        );
        assert_eq!(mapper.map("is_active", &entity).await.unwrap(), json!(true));
        assert_eq!(mapper.map("priority", &entity).await.unwrap(), json!(100));
    }

    #[tokio::test]
    async fn test_map_all() {
        let config = HashMap::from([
            ("name".to_string(), json!("metadata.name")),
            ("type".to_string(), json!({"value": "Web Application"})),
        ]);

        let mapper = FieldMapper::new(config).unwrap();
        let entity = create_test_entity("test-123", "Component");

        let mapped = mapper.map_all(&entity).await.unwrap();

        assert_eq!(mapped.get("name").unwrap(), &json!("test-component"));
        assert_eq!(mapped.get("type").unwrap(), &json!("Web Application"));
    }

    #[tokio::test]
    async fn test_complex_mapping_parse() {
        let config = HashMap::from([(
            "members".to_string(),
            json!({
                "from": "spec.owner",
                "resolve_entity": "Group",
                "extract": "spec.members"
            }),
        )]);

        let mapper = FieldMapper::new(config).unwrap();
        assert!(mapper.has_mapping("members"));
    }
}