/**
 * Validation Rules Routes - FULL CRUD
 *
 * Validation rules are leaf nodes - no children, can be deleted directly
 * technique -> technique_validation_rule
 */

import { Router, Request, Response } from 'express';
import { query, queryOne, transaction } from '../config/database';
import { TechniqueValidationRule, ApiResponse } from '../types';
import { PoolClient } from 'pg';
import { internalError } from '../config/error-response';

const router = Router();

// Parameter type for validation rules
const PARAMETER_TYPE_VALIDATION_RULE = 5;

// Helper: Create parameter entry
const createParameter = async (client: PoolClient): Promise<number> => {
  const maxResult = await client.query('SELECT COALESCE(MAX(parameter_id), 0) + 1 as next_id FROM parameter');
  const nextParamId = maxResult.rows[0].next_id;

  await client.query(`
    INSERT INTO parameter (parameter_id, parameter_type, valid_from, valid_to, created_date, updated_date)
    VALUES ($1, $2, '2026-01-01', '2999-01-01', CURRENT_DATE, CURRENT_DATE)
  `, [nextParamId, PARAMETER_TYPE_VALIDATION_RULE]);

  return nextParamId;
};

// Helper: Get next rule_id
const getNextRuleId = async (client: PoolClient): Promise<number> => {
  const result = await client.query('SELECT COALESCE(MAX(technique_valid_rule_id), 0) + 1 as next_id FROM technique_validation_rule');
  return result.rows[0].next_id;
};

// GET all validation rules
router.get('/', async (req: Request, res: Response) => {
  try {
    const rules = await query<TechniqueValidationRule>(
      'SELECT * FROM technique_validation_rule ORDER BY technique_id, technique_valid_rule_id'
    );
    res.json({
      success: true,
      data: rules,
      count: rules.length
    } as ApiResponse<TechniqueValidationRule[]>);
  } catch (error) {
    res.status(500).json({
      success: false,
      error: error instanceof Error ? error.message : 'Unknown error'
    } as ApiResponse<never>);
  }
});

// GET validation rules with technique info
router.get('/with-techniques', async (req: Request, res: Response) => {
  try {
    const rules = await query<TechniqueValidationRule & { technique_name: string }>(`
      SELECT r.*, t.technique_name
      FROM technique_validation_rule r
      JOIN technique t ON r.technique_id = t.technique_id
      ORDER BY r.technique_id, r.technique_valid_rule_id
    `);
    res.json({
      success: true,
      data: rules,
      count: rules.length
    });
  } catch (error) {
    internalError(res, error);
  }
});

// GET validation rules by technique_id
router.get('/by-technique/:techniqueId', async (req: Request, res: Response) => {
  try {
    const rules = await query<TechniqueValidationRule>(
      'SELECT * FROM technique_validation_rule WHERE technique_id = $1 ORDER BY technique_valid_rule_id',
      [req.params.techniqueId]
    );
    res.json({
      success: true,
      data: rules,
      count: rules.length
    } as ApiResponse<TechniqueValidationRule[]>);
  } catch (error) {
    res.status(500).json({
      success: false,
      error: error instanceof Error ? error.message : 'Unknown error'
    } as ApiResponse<never>);
  }
});

// GET stats — declarat înainte de '/:id', altfel 'stats' e capturat ca :id
router.get('/stats', async (req: Request, res: Response) => {
  try {
    const stats = await query<any>(`
      SELECT
        (SELECT COUNT(*) FROM technique) as total_techniques,
        (SELECT COUNT(DISTINCT technique_id) FROM technique_validation_rule) as techniques_with_rules,
        (SELECT COUNT(*) FROM technique_validation_rule) as total_rules,
        (SELECT COUNT(*) FROM technique WHERE technique_id NOT IN (SELECT DISTINCT technique_id FROM technique_validation_rule)) as techniques_missing_rules
    `);
    res.json({
      success: true,
      data: stats[0]
    });
  } catch (error) {
    internalError(res, error);
  }
});

// GET single validation rule by ID
router.get('/:id', async (req: Request, res: Response) => {
  try {
    const rule = await queryOne<TechniqueValidationRule>(
      'SELECT * FROM technique_validation_rule WHERE technique_valid_rule_id = $1',
      [req.params.id]
    );

    if (!rule) {
      return res.status(404).json({
        success: false,
        error: 'Regula de validare nu a fost găsită'
      });
    }

    res.json({
      success: true,
      data: rule
    });
  } catch (error) {
    internalError(res, error);
  }
});

// POST - Create single validation rule
router.post('/', async (req: Request, res: Response) => {
  try {
    const { technique_id, rule_name, rule_value, description } = req.body;

    // Validation
    if (!technique_id || !rule_name || !rule_value) {
      return res.status(400).json({
        success: false,
        error: 'Câmpuri obligatorii: technique_id, rule_name, rule_value'
      });
    }

    // Verify technique exists
    const technique = await queryOne('SELECT technique_id FROM technique WHERE technique_id = $1', [technique_id]);
    if (!technique) {
      return res.status(400).json({
        success: false,
        error: 'Tehnica specificată nu există'
      });
    }

    const result = await transaction(async (client) => {
      // Create parameter entry
      const parameterId = await createParameter(client);

      // Get next rule ID
      const ruleId = await getNextRuleId(client);

      // Insert rule
      const insertResult = await client.query(`
        INSERT INTO technique_validation_rule (technique_valid_rule_id, technique_id, rule_name, rule_value, description, parameter_id)
        VALUES ($1, $2, $3, $4, $5, $6)
        RETURNING *
      `, [ruleId, technique_id, rule_name, rule_value, description || '', parameterId]);

      return insertResult.rows[0];
    });

    res.status(201).json({
      success: true,
      data: result,
      message: 'Regula de validare a fost creată cu succes'
    });
  } catch (error) {
    internalError(res, error);
  }
});

// POST /bulk-for-technique - Create multiple rules for a single technique
router.post('/bulk-for-technique/:techniqueId', async (req: Request, res: Response) => {
  try {
    const techniqueId = parseInt(req.params.techniqueId);
    const { rules } = req.body;

    if (!rules || !Array.isArray(rules) || rules.length === 0) {
      return res.status(400).json({
        success: false,
        error: 'Câmp obligatoriu: rules (array de {rule_name, rule_value, description})'
      });
    }

    // Verify technique exists
    const technique = await queryOne('SELECT technique_id FROM technique WHERE technique_id = $1', [techniqueId]);
    if (!technique) {
      return res.status(400).json({
        success: false,
        error: 'Tehnica specificată nu există'
      });
    }

    const result = await transaction(async (client) => {
      const created: any[] = [];

      for (const rule of rules) {
        if (!rule.rule_name || !rule.rule_value) {
          throw new Error(`Regulă invalidă: ${JSON.stringify(rule)}. Obligatoriu: rule_name, rule_value`);
        }

        // Create parameter entry
        const parameterId = await createParameter(client);

        // Get next rule ID
        const ruleId = await getNextRuleId(client);

        // Insert rule
        const insertResult = await client.query(`
          INSERT INTO technique_validation_rule (technique_valid_rule_id, technique_id, rule_name, rule_value, description, parameter_id)
          VALUES ($1, $2, $3, $4, $5, $6)
          RETURNING *
        `, [ruleId, techniqueId, rule.rule_name, rule.rule_value, rule.description || '', parameterId]);

        created.push(insertResult.rows[0]);
      }

      return created;
    });

    res.status(201).json({
      success: true,
      data: result,
      count: result.length,
      message: `${result.length} reguli de validare au fost create cu succes`
    });
  } catch (error) {
    internalError(res, error);
  }
});

// PUT - Update validation rule
router.put('/:id', async (req: Request, res: Response) => {
  try {
    const id = req.params.id;
    const { technique_id, rule_name, rule_value, description } = req.body;

    // Check if rule exists
    const existing = await queryOne<TechniqueValidationRule>(
      'SELECT * FROM technique_validation_rule WHERE technique_valid_rule_id = $1',
      [id]
    );

    if (!existing) {
      return res.status(404).json({
        success: false,
        error: 'Regula de validare nu a fost găsită'
      });
    }

    // If changing technique_id, verify it exists
    if (technique_id) {
      const technique = await queryOne('SELECT technique_id FROM technique WHERE technique_id = $1', [technique_id]);
      if (!technique) {
        return res.status(400).json({
          success: false,
          error: 'Tehnica specificată nu există'
        });
      }
    }

    const result = await queryOne<TechniqueValidationRule>(`
      UPDATE technique_validation_rule
      SET technique_id = COALESCE($1, technique_id),
          rule_name = COALESCE($2, rule_name),
          rule_value = COALESCE($3, rule_value),
          description = COALESCE($4, description)
      WHERE technique_valid_rule_id = $5
      RETURNING *
    `, [technique_id, rule_name, rule_value, description, id]);

    res.json({
      success: true,
      data: result,
      message: 'Regula de validare a fost actualizată cu succes'
    });
  } catch (error) {
    internalError(res, error);
  }
});

// DELETE - Delete single validation rule
router.delete('/:id', async (req: Request, res: Response) => {
  try {
    const id = req.params.id;

    // Check if rule exists
    const existing = await queryOne<TechniqueValidationRule>(
      'SELECT * FROM technique_validation_rule WHERE technique_valid_rule_id = $1',
      [id]
    );

    if (!existing) {
      return res.status(404).json({
        success: false,
        error: 'Regula de validare nu a fost găsită'
      });
    }

    // Delete (leaf node - no children to check)
    await query('DELETE FROM technique_validation_rule WHERE technique_valid_rule_id = $1', [id]);

    res.json({
      success: true,
      message: 'Regula de validare a fost ștearsă cu succes',
      deleted: true
    });
  } catch (error) {
    internalError(res, error);
  }
});

// DELETE all validation rules for a technique
router.delete('/by-technique/:techniqueId', async (req: Request, res: Response) => {
  try {
    const techniqueId = req.params.techniqueId;

    // Verify technique exists
    const technique = await queryOne('SELECT technique_id FROM technique WHERE technique_id = $1', [techniqueId]);
    if (!technique) {
      return res.status(404).json({
        success: false,
        error: 'Tehnica specificată nu există'
      });
    }

    const result = await query<TechniqueValidationRule>(
      'DELETE FROM technique_validation_rule WHERE technique_id = $1 RETURNING *',
      [techniqueId]
    );

    res.json({
      success: true,
      data: result,
      count: result.length,
      message: `${result.length} reguli de validare au fost șterse pentru tehnica ${techniqueId}`
    });
  } catch (error) {
    internalError(res, error);
  }
});

export default router;