use crate::tests::types::Suite;
use serde::Deserialize;
use serde_json::Value;
use std::collections::HashMap;
use std::fs;
use std::sync::{Arc, OnceLock, RwLock};

pub fn deserialize_some<'de, D>(deserializer: D) -> Result<Option<Value>, D::Error>
where
  D: serde::Deserializer<'de>,
{
  let v = Value::deserialize(deserializer)?;
  Ok(Some(v))
}

// Type alias for easier reading
type CompiledSuite = Arc<Vec<(Suite, Arc<Result<Arc<crate::database::Database>, crate::drop::Drop>>)>>;

// Global cache mapping filename -> Vector of (Parsed JSON suite, Compiled Database)
static CACHE: OnceLock<RwLock<HashMap<String, CompiledSuite>>> = OnceLock::new();

fn get_cached_file(path: &str) -> CompiledSuite {
  let cache_lock = CACHE.get_or_init(|| RwLock::new(HashMap::new()));

  let file_data = {
    let read_guard = cache_lock.read().unwrap();
    read_guard.get(path).cloned()
  };

  match file_data {
    Some(data) => data,
    None => {
      let mut write_guard = cache_lock.write().unwrap();
      // double check in case another thread compiled while we waited for lock
      if let Some(data) = write_guard.get(path) {
        data.clone()
      } else {
        let content =
          fs::read_to_string(path).unwrap_or_else(|_| panic!("Failed to read file: {}", path));
        let suites: Vec<Suite> = serde_json::from_str(&content)
          .unwrap_or_else(|e| panic!("Failed to parse JSON in {}: {}", path, e));

        let mut compiled_suites = Vec::new();
        for suite in suites {
          let db_result = crate::database::Database::new(&suite.database);
          let compiled_db = match db_result {
            Ok(db) => Ok(Arc::new(db)),
            Err(drop) => Err(drop),
          };
          compiled_suites.push((suite, Arc::new(compiled_db)));
        }

        let new_data = Arc::new(compiled_suites);
        write_guard.insert(path.to_string(), new_data.clone());
        new_data
      }
    }
  }
}

pub fn run_test_case(path: &str, suite_idx: usize, case_idx: usize) -> Result<(), String> {
  let file_data = get_cached_file(path);

  if suite_idx >= file_data.len() {
    panic!("Suite Index {} out of bounds for file {}", suite_idx, path);
  }

  let (group, db) = &file_data[suite_idx];

  if case_idx >= group.tests.len() {
    panic!(
      "Case Index {} out of bounds for suite {} in file {}",
      case_idx, suite_idx, path
    );
  }

  let test = &group.tests[case_idx];
  let mut failures = Vec::<String>::new();

  // For validate/merge/query, if setup failed we must structurally fail this test
  let db_unwrapped = if test.action.as_str() != "compile" && test.action.as_str() != "database_compile" {
    match &**db {
      Ok(valid_db) => Some(valid_db.clone()),
      Err(drop) => {
        let error_messages: Vec<String> = drop
          .errors
          .iter()
          .map(|e| format!("Error {} at path {}: {}", e.code, e.details.path, e.message))
          .collect();
        failures.push(format!(
          "[{}] Cannot run '{}' test '{}': System Setup Compilation structurally failed:\n{}",
          group.description, test.action, test.description, error_messages.join("\n")
        ));
        None
      }
    }
  } else {
    None
  };

  if !failures.is_empty() {
    return Err(failures.join("\n"));
  }

  // 4. Run Tests

  match test.action.as_str() {
    "compile" | "database_compile" => {
      let result = test.run_compile(db);
      if let Err(e) = result {
        println!("TEST COMPILE ERROR FOR '{}': {}", test.description, e);
        failures.push(format!(
          "[{}] Compile Test '{}' failed. Error: {}",
          group.description, test.description, e
        ));
      }
    }
    "validate" => {
      let result = test.run_validate(db_unwrapped.unwrap());
      if let Err(e) = result {
        println!("TEST VALIDATE ERROR FOR '{}': {}", test.description, e);
        failures.push(format!(
          "[{}] Validate Test '{}' failed. Error: {}",
          group.description, test.description, e
        ));
      }
    }
    "merge" => {
      let result = test.run_merge(db_unwrapped.unwrap());
      if let Err(e) = result {
        println!("TEST MERGE ERROR FOR '{}': {}", test.description, e);
        failures.push(format!(
          "[{}] Merge Test '{}' failed. Error: {}",
          group.description, test.description, e
        ));
      }
    }
    "query" => {
      let result = test.run_query(db_unwrapped.unwrap());
      if let Err(e) = result {
        println!("TEST QUERY ERROR FOR '{}': {}", test.description, e);
        failures.push(format!(
          "[{}] Query Test '{}' failed. Error: {}",
          group.description, test.description, e
        ));
      }
    }
    _ => {
      failures.push(format!(
        "[{}] Unknown action '{}' for test '{}'",
        group.description, test.action, test.description
      ));
    }
  }

  if !failures.is_empty() {
    return Err(failures.join("\n"));
  }

  Ok(())
}