use serde::Deserialize;
use std::fs;

#[derive(Debug, Deserialize)]
struct TestSuite {
  #[allow(dead_code)]
  description: String,
  schema: Option<serde_json::Value>,
  // Support JSPG-style test suites with explicit types/enums/puncs
  types: Option<serde_json::Value>,
  enums: Option<serde_json::Value>,
  puncs: Option<serde_json::Value>,
  tests: Vec<TestCase>,
}

#[derive(Debug, Deserialize)]
struct TestCase {
  description: String,
  data: serde_json::Value,
  valid: bool,
  // Support explicit schema ID target for test case
  schema_id: Option<String>,
  // Expected output for masking tests
  #[allow(dead_code)]
  expected: Option<serde_json::Value>,
}

// use crate::validator::registry::REGISTRY; // No longer used directly for tests!
use crate::validator::Validator;
use serde_json::Value;

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))
}

pub fn run_test_file_at_index(path: &str, index: usize) -> Result<(), String> {
  let content =
    fs::read_to_string(path).unwrap_or_else(|_| panic!("Failed to read file: {}", path));
  let suite: Vec<TestSuite> = serde_json::from_str(&content)
    .unwrap_or_else(|e| panic!("Failed to parse JSON in {}: {}", path, e));

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

  let group = &suite[index];
  let mut failures = Vec::<String>::new();

  // Create Validator Instance and parse enums, types, and puncs automatically
  let mut validator = Validator::from_punc_definition(
    group.enums.as_ref(),
    group.types.as_ref(),
    group.puncs.as_ref(),
  );

  // 3. Register root 'schemas' if present (generic test support)
  // Some tests use a raw 'schema' or 'schemas' field at the group level
  if let Some(schema_val) = &group.schema {
    match serde_json::from_value::<crate::validator::schema::Schema>(schema_val.clone()) {
      Ok(mut schema) => {
        let id_clone = schema.obj.id.clone();
        if id_clone.is_some() {
          validator.registry.add(schema);
        } else {
          // Fallback ID if none provided in schema
          let id = format!("test:{}:{}", path, index);
          schema.obj.id = Some(id);
          validator.registry.add(schema);
        }
      }
      Err(e) => {
        eprintln!(
          "DEBUG: FAILED to deserialize group schema for index {}: {}",
          index, e
        );
      }
    }
  }

  // 4. Run Tests
  for (_test_index, test) in group.tests.iter().enumerate() {
    let mut schema_id = test.schema_id.clone();

    // If no explicit schema_id, try to infer from the single schema in the group
    if schema_id.is_none() {
      if let Some(s) = &group.schema {
        // If 'schema' is a single object, use its ID or "root"
        if let Some(obj) = s.as_object() {
          if let Some(id_val) = obj.get("$id") {
            schema_id = id_val.as_str().map(|s| s.to_string());
          }
        }
        if schema_id.is_none() {
          schema_id = Some(format!("test:{}:{}", path, index));
        }
      }
    }

    // Default to the first punc if present (for puncs.json style)
    if schema_id.is_none() {
      if let Some(Value::Array(puncs)) = &group.puncs {
        if let Some(first_punc) = puncs.first() {
          if let Some(Value::Array(schemas)) = first_punc.get("schemas") {
            if let Some(first_schema) = schemas.first() {
              if let Some(id) = first_schema.get("$id").and_then(|v| v.as_str()) {
                schema_id = Some(id.to_string());
              }
            }
          }
        }
      }
    }

    if let Some(sid) = schema_id {
      let result = validator.validate(&sid, &test.data);

      let (got_valid, _errors) = match &result {
        Ok(res) => (res.is_valid(), &res.errors),
        Err(_e) => {
          // If we encounter an execution error (e.g. Schema Not Found),
          // we treat it as a test failure.
          (false, &vec![])
        }
      };

      if let Some(expected) = &test.expected {
        // Masking Test
        let mut data_for_mask = test.data.clone();
        match validator.mask(&sid, &mut data_for_mask) {
          Ok(_) => {
            if !equals(&data_for_mask, expected) {
              let msg = format!(
                "Masking Test '{}' failed.\nExpected: {:?}\nGot: {:?}",
                test.description, expected, data_for_mask
              );
              eprintln!("{}", msg);
              failures.push(msg);
            }
          }
          Err(e) => {
            let msg = format!(
              "Masking Test '{}' failed with execution error: {:?}",
              test.description, e
            );
            eprintln!("{}", msg);
            failures.push(msg);
          }
        }
      } else {
        // Standard Validation Test
        if got_valid != test.valid {
          let error_msg = match &result {
            Ok(res) => format!("{:?}", res.errors),
            Err(e) => format!("Execution Error: {:?}", e),
          };

          failures.push(format!(
            "[{}] Test '{}' failed. Expected: {}, Got: {}. Errors: {}",
            group.description, test.description, test.valid, got_valid, error_msg
          ));
        }
      }
    } else {
      failures.push(format!(
        "[{}] Test '{}' skipped: No schema ID found.",
        group.description, test.description
      ));
    }
  }

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

  Ok(())
}
pub fn run_test_file(path: &str) -> Result<(), String> {
  let content =
    fs::read_to_string(path).unwrap_or_else(|_| panic!("Failed to read file: {}", path));
  let suite: Vec<TestSuite> = serde_json::from_str(&content)
    .unwrap_or_else(|e| panic!("Failed to parse JSON in {}: {}", path, e));

  let mut failures = Vec::<String>::new();
  for (group_index, group) in suite.into_iter().enumerate() {
    // Create Validator Instance and parse enums, types, and puncs automatically
    let mut validator = Validator::from_punc_definition(
      group.enums.as_ref(),
      group.types.as_ref(),
      group.puncs.as_ref(),
    );

    let unique_id = format!("test:{}:{}", path, group_index);

    // Register main 'schema' if present (Standard style)
    if let Some(ref schema_val) = group.schema {
      let mut schema: crate::validator::schema::Schema =
        serde_json::from_value(schema_val.clone()).expect("Failed to parse test schema");

      // If schema has no ID, assign unique_id and use add() or manual insert?
      // Compiler needs ID. Registry::add needs ID.
      if schema.obj.id.is_none() {
        schema.obj.id = Some(unique_id.clone());
      }
      validator.registry.add(schema);
    }

    for test in group.tests {
      // Use explicit schema_id from test, or default to unique_id
      let schema_id = test.schema_id.as_deref().unwrap_or(&unique_id).to_string();

      let result = validator.validate(&schema_id, &test.data);

      if test.valid {
        match result {
          Ok(res) => {
            if !res.is_valid() {
              let msg = format!(
                "Test failed (expected valid): {}\nSchema: {:?}\nData: {:?}\nErrors: {:?}",
                test.description,
                group.schema, // We might need to find the actual schema used if schema_id is custom
                test.data,
                res.errors
              );
              eprintln!("{}", msg);
              failures.push(msg);
            }
          }
          Err(e) => {
            let msg = format!(
              "Test failed (expected valid) but got execution error: {}\nSchema: {:?}\nData: {:?}\nError: {:?}",
              test.description, group.schema, test.data, e
            );
            eprintln!("{}", msg);
            failures.push(msg);
          }
        }
      } else {
        match result {
          Ok(res) => {
            if res.is_valid() {
              let msg = format!(
                "Test failed (expected invalid): {}\nSchema: {:?}\nData: {:?}",
                test.description, group.schema, test.data
              );
              eprintln!("{}", msg);
              failures.push(msg);
            }
          }
          Err(_) => {
            // Expected invalid, got error (which implies invalid/failure), so this is PASS.
          }
        }
      }
    }
  }

  if !failures.is_empty() {
    return Err(format!(
      "{} tests failed in file {}:\n\n{}",
      failures.len(),
      path,
      failures.join("\n\n")
    ));
  }
  Ok(())
}

pub fn is_integer(v: &Value) -> bool {
  match v {
    Value::Number(n) => {
      n.is_i64() || n.is_u64() || n.as_f64().filter(|n| n.fract() == 0.0).is_some()
    }
    _ => false,
  }
}

/// serde_json treats 0 and 0.0 not equal. so we cannot simply use v1==v2
pub fn equals(v1: &Value, v2: &Value) -> bool {
  // eprintln!("Comparing {:?} with {:?}", v1, v2);
  match (v1, v2) {
    (Value::Null, Value::Null) => true,
    (Value::Bool(b1), Value::Bool(b2)) => b1 == b2,
    (Value::Number(n1), Value::Number(n2)) => {
      if let (Some(n1), Some(n2)) = (n1.as_u64(), n2.as_u64()) {
        return n1 == n2;
      }
      if let (Some(n1), Some(n2)) = (n1.as_i64(), n2.as_i64()) {
        return n1 == n2;
      }
      if let (Some(n1), Some(n2)) = (n1.as_f64(), n2.as_f64()) {
        return (n1 - n2).abs() < f64::EPSILON;
      }
      false
    }
    (Value::String(s1), Value::String(s2)) => s1 == s2,
    (Value::Array(arr1), Value::Array(arr2)) => {
      if arr1.len() != arr2.len() {
        return false;
      }
      arr1.iter().zip(arr2).all(|(e1, e2)| equals(e1, e2))
    }
    (Value::Object(obj1), Value::Object(obj2)) => {
      if obj1.len() != obj2.len() {
        return false;
      }
      for (k1, v1) in obj1 {
        if let Some(v2) = obj2.get(k1) {
          if !equals(v1, v2) {
            return false;
          }
        } else {
          return false;
        }
      }
      true
    }
    _ => false,
  }
}