import Joi from 'joi';

// Multi-language validation schema
const multiLangSchema = Joi.object({
    th: Joi.string().required().messages({
        'any.required': 'Thai text is required'
    }),
    en: Joi.string().required().messages({
        'any.required': 'English text is required'
    })
}).required();

const multiLangOptionalSchema = Joi.object({
    th: Joi.string().optional(),
    en: Joi.string().optional()
}).optional();

// ============================================
// Chapter Validators
// ============================================

/**
 * Validator for creating a chapter
 */
export const CreateChapterValidator = Joi.object({
    title: multiLangSchema.messages({
        'any.required': 'Title is required'
    }),
    description: multiLangOptionalSchema,
    sort_order: Joi.number().integer().min(0).optional()
});

/**
 * Validator for updating a chapter
 */
export const UpdateChapterValidator = Joi.object({
    title: multiLangOptionalSchema,
    description: multiLangOptionalSchema,
    sort_order: Joi.number().integer().min(0).optional(),
    is_published: Joi.boolean().optional()
});

/**
 * Validator for reordering a chapter
 */
export const ReorderChapterValidator = Joi.object({
    sort_order: Joi.number().integer().min(0).required().messages({
        'any.required': 'Sort order is required',
        'number.min': 'Sort order must be at least 0'
    })
});

// ============================================
// Lesson Validators
// ============================================

/**
 * Validator for creating a lesson
 */
export const CreateLessonValidator = Joi.object({
    title: multiLangSchema.messages({
        'any.required': 'Title is required'
    }),
    content: multiLangOptionalSchema,
    type: Joi.string().valid('VIDEO', 'QUIZ').required().messages({
        'any.only': 'Type must be either VIDEO or QUIZ',
        'any.required': 'Type is required'
    }),
    sort_order: Joi.number().integer().min(0).optional()
});

/**
 * Validator for updating a lesson
 */
export const UpdateLessonValidator = Joi.object({
    title: multiLangOptionalSchema,
    content: multiLangOptionalSchema,
    duration_minutes: Joi.number().min(0).optional().messages({
        'number.min': 'Duration must be at least 0'
    }),
    sort_order: Joi.number().integer().min(0).optional(),
    prerequisite_lesson_ids: Joi.array().items(Joi.number().integer().positive()).optional(),
    is_published: Joi.boolean().optional()
});

/**
 * Validator for reordering lessons
 */
export const ReorderLessonsValidator = Joi.object({
    lesson_id: Joi.number().integer().positive().required().messages({
        'any.required': 'Lesson ID is required'
    }),
    sort_order: Joi.number().integer().min(0).required().messages({
        'any.required': 'Sort order is required'
    })
});

// ============================================
// Quiz Question Validators
// ============================================

/**
 * Validator for quiz choice
 */
const QuizChoiceValidator = Joi.object({
    text: multiLangSchema.messages({
        'any.required': 'Choice text is required'
    }),
    is_correct: Joi.boolean().required().messages({
        'any.required': 'is_correct is required'
    }),
    sort_order: Joi.number().integer().min(0).optional()
});

/**
 * Validator for adding a question to a quiz
 */
export const AddQuestionValidator = Joi.object({
    question: multiLangSchema.messages({
        'any.required': 'Question is required'
    }),
    explanation: multiLangOptionalSchema,
    question_type: Joi.string()
        .valid('MULTIPLE_CHOICE', 'TRUE_FALSE', 'SHORT_ANSWER')
        .required()
        .messages({
            'any.only': 'Question type must be MULTIPLE_CHOICE, TRUE_FALSE, or SHORT_ANSWER',
            'any.required': 'Question type is required'
        }),
    sort_order: Joi.number().integer().min(0).optional(),
    choices: Joi.array().items(QuizChoiceValidator).min(1).optional().messages({
        'array.min': 'At least one choice is required for multiple choice questions'
    })
});

/**
 * Validator for updating a question
 */
export const UpdateQuestionValidator = Joi.object({
    question: multiLangOptionalSchema,
    explanation: multiLangOptionalSchema,
    question_type: Joi.string()
        .valid('MULTIPLE_CHOICE', 'TRUE_FALSE', 'SHORT_ANSWER')
        .optional()
        .messages({
            'any.only': 'Question type must be MULTIPLE_CHOICE, TRUE_FALSE, or SHORT_ANSWER'
        }),
    sort_order: Joi.number().integer().min(0).optional(),
    choices: Joi.array().items(QuizChoiceValidator).min(1).optional().messages({
        'array.min': 'At least one choice is required'
    })
});

/**
 * Validator for reordering a question
 */
export const ReorderQuestionValidator = Joi.object({
    sort_order: Joi.number().integer().min(0).required().messages({
        'any.required': 'Sort order is required',
        'number.min': 'Sort order must be at least 0'
    })
});

// ============================================
// Quiz Settings Validator
// ============================================

/**
 * Validator for updating quiz settings
 */
export const UpdateQuizValidator = Joi.object({
    title: multiLangOptionalSchema,
    description: multiLangOptionalSchema,
    passing_score: Joi.number().min(0).max(100).optional().messages({
        'number.min': 'Passing score must be at least 0',
        'number.max': 'Passing score must not exceed 100'
    }),
    time_limit: Joi.number().min(0).optional().messages({
        'number.min': 'Time limit must be at least 0'
    }),
    shuffle_questions: Joi.boolean().optional(),
    shuffle_choices: Joi.boolean().optional(),
    show_answers_after_completion: Joi.boolean().optional(),
    is_skippable: Joi.boolean().optional(),
    allow_multiple_attempts: Joi.boolean().optional()
});