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 (general, system, company_specific)
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 prompt type
    if (!type || !['general', 'system', 'company_specific'].includes(type)) {
      return res.status(400).json({ 
        error: 'Valid type query parameter is required (general, system, or company_specific)'
      });
    }
    
    // For company_specific type, company ID is required
    if (type === 'company_specific' && !company) {
      return res.status(400).json({
        error: 'Company ID is required for company_specific prompt type'
      });
    }
    
    // For general and system types, company should not be provided
    if ((type === 'general' || type === 'system') && company) {
      return res.status(400).json({
        error: 'Company ID should not be provided for general or system prompt types'
      });
    }
    
    // Build the query based on the type
    let query, params;
    if (type === 'company_specific') {
      query = 'SELECT * FROM ai_prompts WHERE prompt_type = $1 AND company = $2';
      params = [type, company];
    } else {
      query = 'SELECT * FROM ai_prompts WHERE prompt_type = $1';
      params = [type];
    }
    
    // Execute the query
    const result = await pool.query(query, params);
    
    // Check if any prompt was found
    if (result.rows.length === 0) {
      let errorMessage;
      if (type === 'company_specific') {
        errorMessage = `AI prompt not found for company ${company}`;
      } else {
        errorMessage = `${type.charAt(0).toUpperCase() + type.slice(1)} AI prompt 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
    if (!['general', 'company_specific', 'system'].includes(prompt_type)) {
      return res.status(400).json({ error: 'Prompt type must be either "general", "company_specific", or "system"' });
    }
    
    // Validate company is provided for company-specific prompts
    if (prompt_type === 'company_specific' && !company) {
      return res.status(400).json({ error: 'Company is required for company-specific prompts' });
    }

    // Validate company is not provided for general or system prompts
    if ((prompt_type === 'general' || prompt_type === 'system') && company) {
      return res.status(400).json({ error: 'Company should not be provided for general or system prompts' });
    }

    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,
      company
    ]);

    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 constraint')) {
      if (error.message.includes('unique_company_prompt')) {
        return res.status(409).json({ 
          error: 'A prompt already exists for this company',
          details: error.message
        });
      } else if (error.message.includes('idx_unique_general_prompt')) {
        return res.status(409).json({ 
          error: 'A general prompt already exists',
          details: error.message
        });
      } else if (error.message.includes('idx_unique_system_prompt')) {
        return res.status(409).json({ 
          error: 'A system prompt 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
    if (!['general', 'company_specific', 'system'].includes(prompt_type)) {
      return res.status(400).json({ error: 'Prompt type must be either "general", "company_specific", or "system"' });
    }
    
    // Validate company is provided for company-specific prompts
    if (prompt_type === 'company_specific' && !company) {
      return res.status(400).json({ error: 'Company is required for company-specific prompts' });
    }
    
    // Validate company is not provided for general or system prompts
    if ((prompt_type === 'general' || prompt_type === 'system') && company) {
      return res.status(400).json({ error: 'Company should not be provided for general or system prompts' });
    }

    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
      WHERE id = $4
      RETURNING *
    `, [
      prompt_text,
      prompt_type,
      company,
      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 constraint')) {
      if (error.message.includes('unique_company_prompt')) {
        return res.status(409).json({ 
          error: 'A prompt already exists for this company',
          details: error.message
        });
      } else if (error.message.includes('idx_unique_general_prompt')) {
        return res.status(409).json({ 
          error: 'A general prompt already exists',
          details: error.message
        });
      } else if (error.message.includes('idx_unique_system_prompt')) {
        return res.status(409).json({ 
          error: 'A system prompt 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;