const express = require('express');
const router = express.Router();

// Get all AI prompts
router.get('/', async (req, res) => {
  try {
    const pool = req.app.locals.pool;
    if (!pool) {
      throw new Error('Database pool not initialized');
    }
    
    const result = await pool.query(`
      SELECT * FROM ai_prompts 
      ORDER BY prompt_type ASC, company ASC
    `);
    res.json(result.rows);
  } catch (error) {
    console.error('Error fetching AI prompts:', error);
    res.status(500).json({ 
      error: 'Failed to fetch AI prompts',
      details: error instanceof Error ? error.message : 'Unknown error'
    });
  }
});

// Get prompt by ID
router.get('/:id', async (req, res) => {
  try {
    const { id } = req.params;
    const pool = req.app.locals.pool;
    if (!pool) {
      throw new Error('Database pool not initialized');
    }
    
    const result = await pool.query(`
      SELECT * FROM ai_prompts 
      WHERE id = $1
    `, [id]);

    if (result.rows.length === 0) {
      return res.status(404).json({ error: 'AI prompt not found' });
    }

    res.json(result.rows[0]);
  } catch (error) {
    console.error('Error fetching AI prompt:', error);
    res.status(500).json({ 
      error: 'Failed to fetch AI prompt',
      details: error instanceof Error ? error.message : 'Unknown error'
    });
  }
});

// Get prompt by type (any prompt_type value - extensible)
router.get('/by-type', async (req, res) => {
  try {
    const { type, company } = req.query;
    const pool = req.app.locals.pool;

    if (!pool) {
      throw new Error('Database pool not initialized');
    }

    // Validate type is provided
    if (!type || typeof type !== 'string' || type.trim().length === 0) {
      return res.status(400).json({
        error: 'Valid type query parameter is required'
      });
    }

    // For company_specific types, company ID is required
    const isCompanySpecificType = type.endsWith('_company_specific');
    if (isCompanySpecificType && !company) {
      return res.status(400).json({
        error: 'Company ID is required for company_specific prompt types'
      });
    }

    // For non-company-specific types, company should not be provided
    if (!isCompanySpecificType && company) {
      return res.status(400).json({
        error: 'Company ID should not be provided for non-company-specific prompt types'
      });
    }

    // Build the query based on whether company is provided
    let query, params;
    if (company) {
      query = 'SELECT * FROM ai_prompts WHERE prompt_type = $1 AND company = $2';
      params = [type.trim(), company];
    } else {
      query = 'SELECT * FROM ai_prompts WHERE prompt_type = $1 AND company IS NULL';
      params = [type.trim()];
    }

    // Execute the query
    const result = await pool.query(query, params);

    // Check if any prompt was found
    if (result.rows.length === 0) {
      const errorMessage = company
        ? `AI prompt '${type}' not found for company ${company}`
        : `AI prompt '${type}' not found`;
      return res.status(404).json({ error: errorMessage });
    }

    // Return the first matching prompt
    res.json(result.rows[0]);
  } catch (error) {
    console.error('Error fetching AI prompt by type:', error);
    res.status(500).json({
      error: 'Failed to fetch AI prompt',
      details: error instanceof Error ? error.message : 'Unknown error'
    });
  }
});

// Create new AI prompt
router.post('/', async (req, res) => {
  try {
    const {
      prompt_text,
      prompt_type,
      company
    } = req.body;

    // Validate required fields
    if (!prompt_text || !prompt_type) {
      return res.status(400).json({ error: 'Prompt text and type are required' });
    }

    // Validate prompt_type is a non-empty string (no hardcoded list - extensible)
    if (typeof prompt_type !== 'string' || prompt_type.trim().length === 0) {
      return res.status(400).json({ error: 'Prompt type must be a non-empty string' });
    }

    // For company-specific types (ending with _company_specific), require company
    const isCompanySpecificType = prompt_type.endsWith('_company_specific');
    if (isCompanySpecificType && !company) {
      return res.status(400).json({ error: 'Company is required for company-specific prompt types' });
    }

    // For non-company-specific types, company should not be provided
    if (!isCompanySpecificType && company) {
      return res.status(400).json({ error: 'Company should not be provided for non-company-specific prompt types' });
    }

    const pool = req.app.locals.pool;
    if (!pool) {
      throw new Error('Database pool not initialized');
    }

    const result = await pool.query(`
      INSERT INTO ai_prompts (
        prompt_text,
        prompt_type,
        company
      ) VALUES ($1, $2, $3)
      RETURNING *
    `, [
      prompt_text,
      prompt_type.trim(),
      company || null
    ]);

    res.status(201).json(result.rows[0]);
  } catch (error) {
    console.error('Error creating AI prompt:', error);

    // Check for unique constraint violations
    if (error instanceof Error && error.message.includes('unique')) {
      if (error.message.includes('idx_singleton_with_company')) {
        return res.status(409).json({
          error: 'A prompt of this type already exists for this company',
          details: error.message
        });
      } else if (error.message.includes('idx_singleton_no_company')) {
        return res.status(409).json({
          error: 'A prompt of this type already exists',
          details: error.message
        });
      }
    }

    res.status(500).json({
      error: 'Failed to create AI prompt',
      details: error instanceof Error ? error.message : 'Unknown error'
    });
  }
});

// Update AI prompt
router.put('/:id', async (req, res) => {
  try {
    const { id } = req.params;
    const {
      prompt_text,
      prompt_type,
      company
    } = req.body;

    // Validate required fields
    if (!prompt_text || !prompt_type) {
      return res.status(400).json({ error: 'Prompt text and type are required' });
    }

    // Validate prompt_type is a non-empty string (no hardcoded list - extensible)
    if (typeof prompt_type !== 'string' || prompt_type.trim().length === 0) {
      return res.status(400).json({ error: 'Prompt type must be a non-empty string' });
    }

    // For company-specific types, require company
    const isCompanySpecificType = prompt_type.endsWith('_company_specific');
    if (isCompanySpecificType && !company) {
      return res.status(400).json({ error: 'Company is required for company-specific prompt types' });
    }

    // For non-company-specific types, company should not be provided
    if (!isCompanySpecificType && company) {
      return res.status(400).json({ error: 'Company should not be provided for non-company-specific prompt types' });
    }

    const pool = req.app.locals.pool;
    if (!pool) {
      throw new Error('Database pool not initialized');
    }

    // Check if the prompt exists
    const checkResult = await pool.query('SELECT * FROM ai_prompts WHERE id = $1', [id]);
    if (checkResult.rows.length === 0) {
      return res.status(404).json({ error: 'AI prompt not found' });
    }

    const result = await pool.query(`
      UPDATE ai_prompts
      SET
        prompt_text = $1,
        prompt_type = $2,
        company = $3,
        updated_at = CURRENT_TIMESTAMP
      WHERE id = $4
      RETURNING *
    `, [
      prompt_text,
      prompt_type.trim(),
      company || null,
      id
    ]);

    res.json(result.rows[0]);
  } catch (error) {
    console.error('Error updating AI prompt:', error);

    // Check for unique constraint violations
    if (error instanceof Error && error.message.includes('unique')) {
      if (error.message.includes('idx_singleton_with_company')) {
        return res.status(409).json({
          error: 'A prompt of this type already exists for this company',
          details: error.message
        });
      } else if (error.message.includes('idx_singleton_no_company')) {
        return res.status(409).json({
          error: 'A prompt of this type already exists',
          details: error.message
        });
      }
    }

    res.status(500).json({
      error: 'Failed to update AI prompt',
      details: error instanceof Error ? error.message : 'Unknown error'
    });
  }
});

// Delete AI prompt
router.delete('/:id', async (req, res) => {
  try {
    const { id } = req.params;
    const pool = req.app.locals.pool;
    if (!pool) {
      throw new Error('Database pool not initialized');
    }
    
    const result = await pool.query('DELETE FROM ai_prompts WHERE id = $1 RETURNING *', [id]);

    if (result.rows.length === 0) {
      return res.status(404).json({ error: 'AI prompt not found' });
    }

    res.json({ message: 'AI prompt deleted successfully' });
  } catch (error) {
    console.error('Error deleting AI prompt:', error);
    res.status(500).json({ 
      error: 'Failed to delete AI prompt',
      details: error instanceof Error ? error.message : 'Unknown error'
    });
  }
});

// Error handling middleware
router.use((err, req, res, next) => {
  console.error('AI prompts route error:', err);
  res.status(500).json({ 
    error: 'Internal server error',
    details: err.message
  });
});

module.exports = router;