//! Catalog Versioning System
//!
//! Manages catalog versions, allowing for version control, rollback, and A/B testing

use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};
use uuid::Uuid;

/// Catalog version
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CatalogVersion {
    pub id: Uuid,
    pub catalog_id: Uuid,
    pub version: String,
    pub description: Option<String>,
    pub created_at: DateTime<Utc>,
    pub created_by: Option<Uuid>,
    pub is_active: bool,
    pub is_published: bool,
    pub published_at: Option<DateTime<Utc>>,
    pub metadata: Option<serde_json::Value>,
}

/// Version manager for catalogs
pub struct VersionManager {
    versions: Vec<CatalogVersion>,
}

impl VersionManager {
    /// Create a new version manager
    pub fn new() -> Self {
        Self {
            versions: Vec::new(),
        }
    }

    /// Create a new version
    pub fn create_version(
        &mut self,
        catalog_id: Uuid,
        version: String,
        description: Option<String>,
        created_by: Option<Uuid>,
    ) -> CatalogVersion {
        let catalog_version = CatalogVersion {
            id: Uuid::new_v4(),
            catalog_id,
            version,
            description,
            created_at: Utc::now(),
            created_by,
            is_active: false,
            is_published: false,
            published_at: None,
            metadata: None,
        };
        self.versions.push(catalog_version.clone());
        catalog_version
    }

    /// Publish a version
    pub fn publish_version(&mut self, version_id: Uuid) -> Result<(), String> {
        let catalog_id = {
            let version = self
                .versions
                .iter()
                .find(|v| v.id == version_id)
                .ok_or_else(|| "Version not found".to_string())?
                .catalog_id;
            version
        };

        // Deactivate all other versions of the same catalog
        for v in self.versions.iter_mut() {
            if v.catalog_id == catalog_id && v.id != version_id {
                v.is_active = false;
            }
        }

        // Activate the target version
        if let Some(version) = self.versions.iter_mut().find(|v| v.id == version_id) {
            version.is_active = true;
            version.is_published = true;
            version.published_at = Some(Utc::now());
        }

        Ok(())
    }

    /// Rollback to a previous version
    pub fn rollback_to_version(&mut self, version_id: Uuid) -> Result<(), String> {
        self.publish_version(version_id)
    }

    /// Get active version for a catalog
    pub fn get_active_version(&self, catalog_id: Uuid) -> Option<&CatalogVersion> {
        self.versions
            .iter()
            .find(|v| v.catalog_id == catalog_id && v.is_active)
    }

    /// Get all versions for a catalog
    pub fn get_versions(&self, catalog_id: Uuid) -> Vec<&CatalogVersion> {
        self.versions
            .iter()
            .filter(|v| v.catalog_id == catalog_id)
            .collect()
    }

    /// Compare two versions
    pub fn compare_versions(
        &self,
        version_id_1: Uuid,
        version_id_2: Uuid,
    ) -> Result<VersionDiff, String> {
        let v1 = self
            .versions
            .iter()
            .find(|v| v.id == version_id_1)
            .ok_or_else(|| "Version 1 not found".to_string())?;
        let v2 = self
            .versions
            .iter()
            .find(|v| v.id == version_id_2)
            .ok_or_else(|| "Version 2 not found".to_string())?;

        Ok(VersionDiff {
            version_1: v1.clone(),
            version_2: v2.clone(),
            differences: vec![], // Would contain actual diff in real implementation
        })
    }
}

impl Default for VersionManager {
    fn default() -> Self {
        Self::new()
    }
}

/// Version comparison result
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct VersionDiff {
    pub version_1: CatalogVersion,
    pub version_2: CatalogVersion,
    pub differences: Vec<String>,
}
