from pydantic import BaseModel, Field, field_validator
from typing import Optional


class TranslationRequest(BaseModel):
    """Translation request schema"""
    text: str = Field(..., description="Text to translate", min_length=1, max_length=5000)
    source_lang: str = Field(..., description="Source language code (e.g., 'en', 'ms', 'bn', etc.)", min_length=2, max_length=5)
    target_lang: str = Field(..., description="Target language code (e.g., 'en', 'ms', 'bn', etc.)", min_length=2, max_length=5)

    @field_validator('source_lang', 'target_lang')
    @classmethod
    def validate_lang_code(cls, v: str) -> str:
        """Validate language code format"""
        return v.lower().strip()

    class Config:
        json_schema_extra = {
            "example": {
                "text": "Selamat pagi, apa khabar?",
                "source_lang": "ms",
                "target_lang": "en"
            }
        }


class TranslationResponse(BaseModel):
    """Translation response schema"""
    original_text: str = Field(..., description="Original input text")
    translated_text: str = Field(..., description="Translated text")
    source_lang: str = Field(..., description="Source language code")
    target_lang: str = Field(..., description="Target language code")
    model_used: str = Field(..., description="Translation model identifier")

    class Config:
        json_schema_extra = {
            "example": {
                "original_text": "Selamat pagi, apa khabar?",
                "translated_text": "Good morning, how are you?",
                "source_lang": "ms",
                "target_lang": "en",
                "model_used": "Helsinki-NLP/opus-mt-ms-en"
            }
        }


class HealthResponse(BaseModel):
    """Health check response"""
    status: str
    message: str
    models_loaded: bool