use sea_orm::{ColumnTrait, ConnectionTrait, EntityTrait, FromQueryResult, QueryFilter, Statement};
use uuid::Uuid;

use erp_core::error::{AppError, AppResult};
use erp_core::events::EventBus;

use crate::data_dto::PluginDataResp;
use crate::dynamic_table::{sanitize_identifier, DynamicTableManager};
use crate::entity::plugin;
use crate::entity::plugin_entity;
use crate::error::PluginError;
use crate::manifest::PluginField;
use crate::state::EntityInfo;

pub struct PluginDataService;

impl PluginDataService {
    /// 创建插件数据
    pub async fn create(
        plugin_id: Uuid,
        entity_name: &str,
        tenant_id: Uuid,
        operator_id: Uuid,
        data: serde_json::Value,
        db: &sea_orm::DatabaseConnection,
        _event_bus: &EventBus,
    ) -> AppResult<PluginDataResp> {
        let info = resolve_entity_info(plugin_id, entity_name, tenant_id, db).await?;
        let fields = info.fields()?;
        validate_data(&data, &fields)?;
        validate_ref_entities(&data, &fields, entity_name, plugin_id, tenant_id, db, true, None).await?;

        let (sql, values) =
            DynamicTableManager::build_insert_sql(&info.table_name, tenant_id, operator_id, &data);

        #[derive(FromQueryResult)]
        struct InsertResult {
            id: Uuid,
            data: serde_json::Value,
            created_at: chrono::DateTime<chrono::Utc>,
            updated_at: chrono::DateTime<chrono::Utc>,
            version: i32,
        }

        let result = InsertResult::find_by_statement(Statement::from_sql_and_values(
            sea_orm::DatabaseBackend::Postgres,
            sql,
            values,
        ))
        .one(db)
        .await?
        .ok_or_else(|| PluginError::DatabaseError("INSERT 未返回结果".to_string()))?;

        Ok(PluginDataResp {
            id: result.id.to_string(),
            data: result.data,
            created_at: Some(result.created_at),
            updated_at: Some(result.updated_at),
            version: Some(result.version),
        })
    }

    /// 列表查询（支持过滤/搜索/排序/Generated Column 路由）
    pub async fn list(
        plugin_id: Uuid,
        entity_name: &str,
        tenant_id: Uuid,
        page: u64,
        page_size: u64,
        db: &sea_orm::DatabaseConnection,
        filter: Option<serde_json::Value>,
        search: Option<String>,
        sort_by: Option<String>,
        sort_order: Option<String>,
        cache: &moka::sync::Cache<String, EntityInfo>,
    ) -> AppResult<(Vec<PluginDataResp>, u64)> {
        let info =
            resolve_entity_info_cached(plugin_id, entity_name, tenant_id, db, cache).await?;

        // 获取 searchable 字段列表
        let entity_fields = info.fields()?;
        let search_tuple = {
            let searchable: Vec<&str> = entity_fields
                .iter()
                .filter(|f| f.searchable == Some(true))
                .map(|f| f.name.as_str())
                .collect();
            match (searchable.is_empty(), &search) {
                (false, Some(kw)) => Some((searchable.join(","), kw.clone())),
                _ => None,
            }
        };

        // Count
        let (count_sql, count_values) =
            DynamicTableManager::build_count_sql(&info.table_name, tenant_id);
        #[derive(FromQueryResult)]
        struct CountResult {
            count: i64,
        }
        let total = CountResult::find_by_statement(Statement::from_sql_and_values(
            sea_orm::DatabaseBackend::Postgres,
            count_sql,
            count_values,
        ))
        .one(db)
        .await?
        .map(|r| r.count as u64)
        .unwrap_or(0);

        // Query — 使用 Generated Column 路由
        let offset = page.saturating_sub(1) * page_size;
        let (sql, values) = DynamicTableManager::build_filtered_query_sql_ex(
            &info.table_name,
            tenant_id,
            page_size,
            offset,
            filter,
            search_tuple,
            sort_by,
            sort_order,
            &info.generated_fields,
        )
        .map_err(|e| AppError::Validation(e))?;

        #[derive(FromQueryResult)]
        struct DataRow {
            id: Uuid,
            data: serde_json::Value,
            created_at: chrono::DateTime<chrono::Utc>,
            updated_at: chrono::DateTime<chrono::Utc>,
            version: i32,
        }

        let rows = DataRow::find_by_statement(Statement::from_sql_and_values(
            sea_orm::DatabaseBackend::Postgres,
            sql,
            values,
        ))
        .all(db)
        .await?;

        let items = rows
            .into_iter()
            .map(|r| PluginDataResp {
                id: r.id.to_string(),
                data: r.data,
                created_at: Some(r.created_at),
                updated_at: Some(r.updated_at),
                version: Some(r.version),
            })
            .collect();

        Ok((items, total))
    }

    /// 按 ID 获取
    pub async fn get_by_id(
        plugin_id: Uuid,
        entity_name: &str,
        id: Uuid,
        tenant_id: Uuid,
        db: &sea_orm::DatabaseConnection,
    ) -> AppResult<PluginDataResp> {
        let info = resolve_entity_info(plugin_id, entity_name, tenant_id, db).await?;
        let (sql, values) = DynamicTableManager::build_get_by_id_sql(&info.table_name, id, tenant_id);

        #[derive(FromQueryResult)]
        struct DataRow {
            id: Uuid,
            data: serde_json::Value,
            created_at: chrono::DateTime<chrono::Utc>,
            updated_at: chrono::DateTime<chrono::Utc>,
            version: i32,
        }

        let row = DataRow::find_by_statement(Statement::from_sql_and_values(
            sea_orm::DatabaseBackend::Postgres,
            sql,
            values,
        ))
        .one(db)
        .await?
        .ok_or_else(|| AppError::NotFound("记录不存在".to_string()))?;

        Ok(PluginDataResp {
            id: row.id.to_string(),
            data: row.data,
            created_at: Some(row.created_at),
            updated_at: Some(row.updated_at),
            version: Some(row.version),
        })
    }

    /// 更新
    pub async fn update(
        plugin_id: Uuid,
        entity_name: &str,
        id: Uuid,
        tenant_id: Uuid,
        operator_id: Uuid,
        data: serde_json::Value,
        expected_version: i32,
        db: &sea_orm::DatabaseConnection,
        _event_bus: &EventBus,
    ) -> AppResult<PluginDataResp> {
        let info = resolve_entity_info(plugin_id, entity_name, tenant_id, db).await?;
        let fields = info.fields()?;
        validate_data(&data, &fields)?;
        validate_ref_entities(&data, &fields, entity_name, plugin_id, tenant_id, db, false, Some(id)).await?;

        // 循环引用检测
        for field in &fields {
            if field.no_cycle == Some(true) && data.get(&field.name).is_some() {
                check_no_cycle(id, field, &data, &info.table_name, tenant_id, db).await?;
            }
        }

        let (sql, values) = DynamicTableManager::build_update_sql(
            &info.table_name,
            id,
            tenant_id,
            operator_id,
            &data,
            expected_version,
        );

        #[derive(FromQueryResult)]
        struct UpdateResult {
            id: Uuid,
            data: serde_json::Value,
            created_at: chrono::DateTime<chrono::Utc>,
            updated_at: chrono::DateTime<chrono::Utc>,
            version: i32,
        }

        let result = UpdateResult::find_by_statement(Statement::from_sql_and_values(
            sea_orm::DatabaseBackend::Postgres,
            sql,
            values,
        ))
        .one(db)
        .await?
        .ok_or_else(|| AppError::VersionMismatch)?;

        Ok(PluginDataResp {
            id: result.id.to_string(),
            data: result.data,
            created_at: Some(result.created_at),
            updated_at: Some(result.updated_at),
            version: Some(result.version),
        })
    }

    /// 删除（软删除）
    pub async fn delete(
        plugin_id: Uuid,
        entity_name: &str,
        id: Uuid,
        tenant_id: Uuid,
        db: &sea_orm::DatabaseConnection,
        _event_bus: &EventBus,
    ) -> AppResult<()> {
        let info = resolve_entity_info(plugin_id, entity_name, tenant_id, db).await?;
        let (sql, values) = DynamicTableManager::build_delete_sql(&info.table_name, id, tenant_id);

        db.execute(Statement::from_sql_and_values(
            sea_orm::DatabaseBackend::Postgres,
            sql,
            values,
        ))
        .await?;

        Ok(())
    }

    /// 统计记录数（支持过滤和搜索）
    pub async fn count(
        plugin_id: Uuid,
        entity_name: &str,
        tenant_id: Uuid,
        db: &sea_orm::DatabaseConnection,
        filter: Option<serde_json::Value>,
        search: Option<String>,
    ) -> AppResult<u64> {
        let info = resolve_entity_info(plugin_id, entity_name, tenant_id, db).await?;

        let entity_fields = info.fields()?;
        let search_tuple = {
            let searchable: Vec<&str> = entity_fields
                .iter()
                .filter(|f| f.searchable == Some(true))
                .map(|f| f.name.as_str())
                .collect();
            match (searchable.is_empty(), &search) {
                (false, Some(kw)) => Some((searchable.join(","), kw.clone())),
                _ => None,
            }
        };

        let (sql, values) = DynamicTableManager::build_filtered_count_sql(
            &info.table_name,
            tenant_id,
            filter,
            search_tuple,
        )
        .map_err(|e| AppError::Validation(e))?;

        #[derive(FromQueryResult)]
        struct CountResult {
            count: i64,
        }

        let result = CountResult::find_by_statement(Statement::from_sql_and_values(
            sea_orm::DatabaseBackend::Postgres,
            sql,
            values,
        ))
        .one(db)
        .await?
        .map(|r| r.count as u64)
        .unwrap_or(0);

        Ok(result)
    }

    /// 聚合查询 — 按字段分组计数
    /// 返回 [(分组键, 计数), ...]
    pub async fn aggregate(
        plugin_id: Uuid,
        entity_name: &str,
        tenant_id: Uuid,
        db: &sea_orm::DatabaseConnection,
        group_by_field: &str,
        filter: Option<serde_json::Value>,
    ) -> AppResult<Vec<(String, i64)>> {
        let info = resolve_entity_info(plugin_id, entity_name, tenant_id, db).await?;

        let (sql, values) = DynamicTableManager::build_aggregate_sql(
            &info.table_name,
            tenant_id,
            group_by_field,
            filter,
        )
        .map_err(|e| AppError::Validation(e))?;

        #[derive(FromQueryResult)]
        struct AggRow {
            key: Option<String>,
            count: i64,
        }

        let rows = AggRow::find_by_statement(Statement::from_sql_and_values(
            sea_orm::DatabaseBackend::Postgres,
            sql,
            values,
        ))
        .all(db)
        .await?;

        let result = rows
            .into_iter()
            .map(|r| (r.key.unwrap_or_default(), r.count))
            .collect();

        Ok(result)
    }

    /// 聚合查询（预留 Redis 缓存接口）
    pub async fn aggregate_cached(
        plugin_id: Uuid,
        entity_name: &str,
        tenant_id: Uuid,
        db: &sea_orm::DatabaseConnection,
        group_by_field: &str,
        filter: Option<serde_json::Value>,
    ) -> AppResult<Vec<(String, i64)>> {
        // TODO: 未来版本添加 Redis 缓存层
        Self::aggregate(plugin_id, entity_name, tenant_id, db, group_by_field, filter).await
    }
}

/// 从 plugins 表解析 manifest metadata.id（如 "erp-crm"）
pub async fn resolve_manifest_id(
    plugin_id: Uuid,
    tenant_id: Uuid,
    db: &sea_orm::DatabaseConnection,
) -> AppResult<String> {
    let model = plugin::Entity::find()
        .filter(plugin::Column::Id.eq(plugin_id))
        .filter(plugin::Column::TenantId.eq(tenant_id))
        .filter(plugin::Column::DeletedAt.is_null())
        .one(db)
        .await?
        .ok_or_else(|| AppError::NotFound(format!("插件 {} 不存在", plugin_id)))?;

    let manifest: crate::manifest::PluginManifest =
        serde_json::from_value(model.manifest_json)
            .map_err(|e| AppError::Internal(format!("解析插件 manifest 失败: {}", e)))?;

    Ok(manifest.metadata.id)
}

/// 从 plugin_entities 表获取实体完整信息（带租户隔离）
/// 注意：此函数不填充 generated_fields，仅用于非 list 场景
async fn resolve_entity_info(
    plugin_id: Uuid,
    entity_name: &str,
    tenant_id: Uuid,
    db: &sea_orm::DatabaseConnection,
) -> AppResult<EntityInfo> {
    let entity = plugin_entity::Entity::find()
        .filter(plugin_entity::Column::PluginId.eq(plugin_id))
        .filter(plugin_entity::Column::TenantId.eq(tenant_id))
        .filter(plugin_entity::Column::EntityName.eq(entity_name))
        .filter(plugin_entity::Column::DeletedAt.is_null())
        .one(db)
        .await?
        .ok_or_else(|| {
            AppError::NotFound(format!("插件实体 {}/{} 不存在", plugin_id, entity_name))
        })?;

    Ok(EntityInfo {
        table_name: entity.table_name,
        schema_json: entity.schema_json,
        generated_fields: vec![], // 旧路径，不追踪 generated_fields
    })
}

/// 从缓存或数据库获取实体信息（带 generated_fields 解析）
pub async fn resolve_entity_info_cached(
    plugin_id: Uuid,
    entity_name: &str,
    tenant_id: Uuid,
    db: &sea_orm::DatabaseConnection,
    cache: &moka::sync::Cache<String, EntityInfo>,
) -> AppResult<EntityInfo> {
    let cache_key = format!("{}:{}:{}", plugin_id, entity_name, tenant_id);
    if let Some(info) = cache.get(&cache_key) {
        return Ok(info);
    }

    let entity = plugin_entity::Entity::find()
        .filter(plugin_entity::Column::PluginId.eq(plugin_id))
        .filter(plugin_entity::Column::TenantId.eq(tenant_id))
        .filter(plugin_entity::Column::EntityName.eq(entity_name))
        .filter(plugin_entity::Column::DeletedAt.is_null())
        .one(db)
        .await?
        .ok_or_else(|| {
            AppError::NotFound(format!("插件实体 {}/{} 不存在", plugin_id, entity_name))
        })?;

    // 解析 generated_fields
    let entity_def: crate::manifest::PluginEntity =
        serde_json::from_value(entity.schema_json.clone())
            .map_err(|e| AppError::Internal(format!("解析 entity schema 失败: {}", e)))?;
    let generated_fields: Vec<String> = entity_def
        .fields
        .iter()
        .filter(|f| f.field_type.supports_generated_column())
        .filter(|f| {
            f.unique
                || f.sortable == Some(true)
                || f.filterable == Some(true)
                || (f.required && (f.sortable == Some(true) || f.filterable == Some(true)))
        })
        .map(|f| sanitize_identifier(&f.name))
        .collect();

    let info = EntityInfo {
        table_name: entity.table_name,
        schema_json: entity.schema_json,
        generated_fields,
    };

    cache.insert(cache_key, info.clone());
    Ok(info)
}

/// 校验数据：检查 required 字段 + 正则校验
fn validate_data(data: &serde_json::Value, fields: &[PluginField]) -> AppResult<()> {
    let obj = data.as_object().ok_or_else(|| {
        AppError::Validation("data 必须是 JSON 对象".to_string())
    })?;

    for field in fields {
        let label = field.display_name.as_deref().unwrap_or(&field.name);

        // required 检查
        if field.required && !obj.contains_key(&field.name) {
            return Err(AppError::Validation(format!("字段 '{}' 不能为空", label)));
        }

        // 正则校验
        if let Some(validation) = &field.validation {
            if let Some(pattern) = &validation.pattern {
                if let Some(val) = obj.get(&field.name) {
                    let str_val = val.as_str().unwrap_or("");
                    if !str_val.is_empty() {
                        let re = regex::Regex::new(pattern)
                            .map_err(|e| AppError::Internal(format!("正则表达式编译失败: {}", e)))?;
                        if !re.is_match(str_val) {
                            let default_msg = format!("字段 '{}' 格式不正确", label);
                            let msg = validation.message.as_deref()
                                .unwrap_or(&default_msg);
                            return Err(AppError::Validation(msg.to_string()));
                        }
                    }
                }
            }
        }
    }

    Ok(())
}

/// 校验外键引用 — 检查 ref_entity 字段指向的记录是否存在
async fn validate_ref_entities(
    data: &serde_json::Value,
    fields: &[PluginField],
    current_entity: &str,
    plugin_id: Uuid,
    tenant_id: Uuid,
    db: &sea_orm::DatabaseConnection,
    is_create: bool,
    record_id: Option<Uuid>,
) -> AppResult<()> {
    let obj = data.as_object().ok_or_else(|| {
        AppError::Validation("data 必须是 JSON 对象".to_string())
    })?;

    for field in fields {
        let Some(ref_entity_name) = &field.ref_entity else { continue };
        let Some(val) = obj.get(&field.name) else { continue };
        let str_val = val.as_str().unwrap_or("").trim().to_string();

        if str_val.is_empty() && !field.required { continue; }
        if str_val.is_empty() { continue; }

        let ref_id = Uuid::parse_str(&str_val).map_err(|_| {
            AppError::Validation(format!(
                "字段 '{}' 的值 '{}' 不是有效的 UUID",
                field.display_name.as_deref().unwrap_or(&field.name),
                str_val
            ))
        })?;

        // 自引用 + create：跳过（记录尚未存在）
        if ref_entity_name == current_entity && is_create {
            continue;
        }
        // 自引用 + update：检查是否引用自身
        if ref_entity_name == current_entity && !is_create {
            if let Some(rid) = record_id {
                if ref_id == rid { continue; }
            }
        }

        // 查询被引用记录是否存在
        let manifest_id = resolve_manifest_id(plugin_id, tenant_id, db).await?;
        let ref_table = DynamicTableManager::table_name(&manifest_id, ref_entity_name);

        let check_sql = format!(
            "SELECT 1 as check_result FROM \"{}\" WHERE id = $1 AND tenant_id = $2 AND deleted_at IS NULL LIMIT 1",
            ref_table
        );
        #[derive(FromQueryResult)]
        struct ExistsCheck { check_result: Option<i32> }
        let result = ExistsCheck::find_by_statement(Statement::from_sql_and_values(
            sea_orm::DatabaseBackend::Postgres,
            check_sql,
            [ref_id.into(), tenant_id.into()],
        )).one(db).await?;

        if result.is_none() {
            return Err(AppError::Validation(format!(
                "引用的 {} 记录不存在（ID: {}）",
                ref_entity_name, ref_id
            )));
        }
    }
    Ok(())
}

/// 循环引用检测 — 用于 no_cycle 字段
async fn check_no_cycle(
    record_id: Uuid,
    field: &PluginField,
    data: &serde_json::Value,
    table_name: &str,
    tenant_id: Uuid,
    db: &sea_orm::DatabaseConnection,
) -> AppResult<()> {
    let Some(val) = data.get(&field.name) else { return Ok(()) };
    let new_parent = val.as_str().unwrap_or("").trim().to_string();
    if new_parent.is_empty() { return Ok(()); }

    let new_parent_id = Uuid::parse_str(&new_parent).map_err(|_| {
        AppError::Validation("parent_id 不是有效的 UUID".to_string())
    })?;

    let field_name = sanitize_identifier(&field.name);
    let mut visited = vec![record_id];
    let mut current_id = new_parent_id;

    for _ in 0..100 {
        if visited.contains(&current_id) {
            let label = field.display_name.as_deref().unwrap_or(&field.name);
            return Err(AppError::Validation(format!(
                "字段 '{}' 形成循环引用", label
            )));
        }
        visited.push(current_id);

        let query_sql = format!(
            "SELECT data->>'{}' as parent FROM \"{}\" WHERE id = $1 AND tenant_id = $2 AND deleted_at IS NULL",
            field_name, table_name
        );
        #[derive(FromQueryResult)]
        struct ParentRow { parent: Option<String> }
        let row = ParentRow::find_by_statement(Statement::from_sql_and_values(
            sea_orm::DatabaseBackend::Postgres,
            query_sql,
            [current_id.into(), tenant_id.into()],
        )).one(db).await?;

        match row {
            Some(r) => {
                let parent = r.parent.unwrap_or_default().trim().to_string();
                if parent.is_empty() { break; }
                current_id = Uuid::parse_str(&parent).map_err(|_| {
                    AppError::Internal("parent_id 不是有效的 UUID".to_string())
                })?;
            }
            None => break,
        }
    }
    Ok(())
}

#[cfg(test)]
mod validate_tests {
    use super::*;
    use crate::manifest::{FieldValidation, PluginField, PluginFieldType};

    fn make_field(name: &str, pattern: Option<&str>, message: Option<&str>) -> PluginField {
        PluginField {
            name: name.to_string(),
            field_type: PluginFieldType::String,
            required: false,
            validation: pattern.map(|p| FieldValidation {
                pattern: Some(p.to_string()),
                message: message.map(|m| m.to_string()),
            }),
            ..PluginField::default_for_field()
        }
    }

    #[test]
    fn validate_phone_pattern_rejects_invalid() {
        let fields = vec![make_field("phone", Some("^1[3-9]\\d{9}$"), Some("手机号格式不正确"))];
        let data = serde_json::json!({"phone": "1234"});
        let result = validate_data(&data, &fields);
        assert!(result.is_err());
    }

    #[test]
    fn validate_phone_pattern_accepts_valid() {
        let fields = vec![make_field("phone", Some("^1[3-9]\\d{9}$"), Some("手机号格式不正确"))];
        let data = serde_json::json!({"phone": "13812345678"});
        let result = validate_data(&data, &fields);
        assert!(result.is_ok());
    }

    #[test]
    fn validate_empty_optional_field_skips_pattern() {
        let fields = vec![make_field("phone", Some("^1[3-9]\\d{9}$"), None)];
        let data = serde_json::json!({"phone": ""});
        let result = validate_data(&data, &fields);
        assert!(result.is_ok());
    }
}