/**
 * Prompt Loader
 *
 * Utilities to load AI prompts from the ai_prompts PostgreSQL table.
 * Supports loading prompts by base type (e.g., 'name_validation' loads
 * name_validation_system, name_validation_general, and optionally
 * name_validation_company_specific).
 */

/**
 * Load a single prompt by exact type
 * @param {Object} pool - PostgreSQL pool
 * @param {string} promptType - Exact prompt type (e.g., 'name_validation_system')
 * @param {string} [company] - Company identifier (for company_specific types)
 * @returns {Promise<string|null>} Prompt text or null if not found
 */
async function loadPromptByType(pool, promptType, company = null) {
  try {
    let result;

    if (company) {
      result = await pool.query(
        'SELECT prompt_text FROM ai_prompts WHERE prompt_type = $1 AND company = $2',
        [promptType, company]
      );
    } else {
      result = await pool.query(
        'SELECT prompt_text FROM ai_prompts WHERE prompt_type = $1 AND company IS NULL',
        [promptType]
      );
    }

    return result.rows[0]?.prompt_text || null;
  } catch (error) {
    console.error(`[PromptLoader] Error loading ${promptType} prompt:`, error.message);
    return null;
  }
}

/**
 * Load all prompts for a task type (system, general, and optionally company-specific)
 *
 * @param {Object} pool - PostgreSQL pool
 * @param {string} baseType - Base type name (e.g., 'name_validation', 'description_validation')
 * @param {string|null} [company] - Optional company ID for company-specific prompts
 * @returns {Promise<{system: string|null, general: string|null, companySpecific: string|null}>}
 */
async function loadPromptsByType(pool, baseType, company = null) {
  const systemType = `${baseType}_system`;
  const generalType = `${baseType}_general`;
  const companyType = `${baseType}_company_specific`;

  // Load system and general prompts in parallel
  const [system, general] = await Promise.all([
    loadPromptByType(pool, systemType),
    loadPromptByType(pool, generalType)
  ]);

  // Load company-specific prompt if company is provided
  let companySpecific = null;
  if (company) {
    companySpecific = await loadPromptByType(pool, companyType, company);
  }

  return {
    system,
    general,
    companySpecific
  };
}

/**
 * Load name validation prompts
 * @param {Object} pool - PostgreSQL pool
 * @param {string|null} [company] - Optional company ID
 * @returns {Promise<{system: string|null, general: string|null, companySpecific: string|null}>}
 */
async function loadNameValidationPrompts(pool, company = null) {
  return loadPromptsByType(pool, 'name_validation', company);
}

/**
 * Load description validation prompts
 * @param {Object} pool - PostgreSQL pool
 * @param {string|null} [company] - Optional company ID
 * @returns {Promise<{system: string|null, general: string|null, companySpecific: string|null}>}
 */
async function loadDescriptionValidationPrompts(pool, company = null) {
  return loadPromptsByType(pool, 'description_validation', company);
}

/**
 * Load sanity check prompts (no company-specific variant)
 * @param {Object} pool - PostgreSQL pool
 * @returns {Promise<{system: string|null, general: string|null, companySpecific: null}>}
 */
async function loadSanityCheckPrompts(pool) {
  return loadPromptsByType(pool, 'sanity_check', null);
}

/**
 * Load bulk validation prompts (GPT-5 validation)
 * @param {Object} pool - PostgreSQL pool
 * @param {string|null} [company] - Optional company ID
 * @returns {Promise<{system: string|null, general: string|null, companySpecific: string|null}>}
 */
async function loadBulkValidationPrompts(pool, company = null) {
  return loadPromptsByType(pool, 'bulk_validation', company);
}

/**
 * Load bulk validation prompts for multiple companies at once
 * @param {Object} pool - PostgreSQL pool
 * @param {string[]} companyIds - Array of company IDs
 * @returns {Promise<{system: string|null, general: string|null, companyPrompts: Map<string, string>}>}
 */
async function loadBulkValidationPromptsForCompanies(pool, companyIds = []) {
  // Load system and general prompts
  const [system, general] = await Promise.all([
    loadPromptByType(pool, 'bulk_validation_system'),
    loadPromptByType(pool, 'bulk_validation_general')
  ]);

  // Load company-specific prompts for all provided companies
  const companyPrompts = new Map();

  if (companyIds.length > 0) {
    try {
      const result = await pool.query(
        `SELECT company, prompt_text FROM ai_prompts
         WHERE prompt_type = 'bulk_validation_company_specific'
         AND company = ANY($1)`,
        [companyIds]
      );

      for (const row of result.rows) {
        companyPrompts.set(row.company, row.prompt_text);
      }
    } catch (error) {
      console.error('[PromptLoader] Error loading company-specific prompts:', error.message);
    }
  }

  return {
    system,
    general,
    companyPrompts
  };
}

/**
 * Validate that required prompts exist, throw error if missing
 * @param {Object} prompts - Prompts object from loadPromptsByType
 * @param {string} baseType - Base type for error messages
 * @param {Object} options - Validation options
 * @param {boolean} [options.requireSystem=true] - Require system prompt
 * @param {boolean} [options.requireGeneral=true] - Require general prompt
 * @throws {Error} If required prompts are missing
 */
function validateRequiredPrompts(prompts, baseType, options = {}) {
  const { requireSystem = true, requireGeneral = true } = options;
  const missing = [];

  if (requireSystem && !prompts.system) {
    missing.push(`${baseType}_system`);
  }

  if (requireGeneral && !prompts.general) {
    missing.push(`${baseType}_general`);
  }

  if (missing.length > 0) {
    throw new Error(
      `Missing required AI prompts: ${missing.join(', ')}. ` +
      `Please add these prompts in Settings > AI Validation Prompts.`
    );
  }
}

module.exports = {
  // Core loader
  loadPromptByType,
  loadPromptsByType,

  // Task-specific loaders
  loadNameValidationPrompts,
  loadDescriptionValidationPrompts,
  loadSanityCheckPrompts,
  loadBulkValidationPrompts,
  loadBulkValidationPromptsForCompanies,

  // Validation
  validateRequiredPrompts
};