import { getAutomationRulesByUser } from "./db";
import { Invoice } from "../drizzle/schema";

interface Condition {
  field: string;
  operator: string;
  value: string;
}

interface Actions {
  typeAchat?: string;
  serviceConcerne?: string;
  ventilationComptable?: string;
}

/**
 * Evaluate a single condition against an invoice
 */
function evaluateCondition(invoice: Invoice, condition: Condition): boolean {
  const fieldValue = invoice[condition.field as keyof Invoice];
  
  if (fieldValue === null || fieldValue === undefined) {
    return false;
  }

  const valueStr = String(fieldValue).toLowerCase();
  const conditionValue = condition.value.toLowerCase();

  switch (condition.operator) {
    case "contains":
      return valueStr.includes(conditionValue);
    case "equals":
      return valueStr === conditionValue;
    case "startsWith":
      return valueStr.startsWith(conditionValue);
    case "endsWith":
      return valueStr.endsWith(conditionValue);
    case ">":
      return Number(fieldValue) > Number(condition.value);
    case "<":
      return Number(fieldValue) < Number(condition.value);
    case ">=":
      return Number(fieldValue) >= Number(condition.value);
    case "<=":
      return Number(fieldValue) <= Number(condition.value);
    default:
      return false;
  }
}

/**
 * Evaluate all conditions for a rule based on the logic (AND/OR)
 */
function evaluateConditions(
  invoice: Invoice,
  conditions: Condition[],
  logic: "AND" | "OR"
): boolean {
  if (conditions.length === 0) {
    return false;
  }

  if (logic === "AND") {
    return conditions.every((condition) => evaluateCondition(invoice, condition));
  } else {
    return conditions.some((condition) => evaluateCondition(invoice, condition));
  }
}

/**
 * Apply automation rules to an invoice and return the fields to update
 * Returns an object with the fields that should be updated based on matching rules
 */
export async function applyAutomationRules(
  userId: number,
  invoice: Invoice
): Promise<Partial<Invoice>> {
  const rules = await getAutomationRulesByUser(userId);
  const updates: Partial<Invoice> = {};
  const autoFilledFieldsList: string[] = [];

  // Process rules in priority order (already sorted by priority in getAutomationRulesByUser)
  for (const rule of rules) {
    // Skip inactive rules
    if (rule.isActive !== 1) {
      continue;
    }

    try {
      const conditions: Condition[] = JSON.parse(rule.conditions);
      const actions: Actions = JSON.parse(rule.actions);

      // Evaluate conditions
      const conditionsMatch = evaluateConditions(
        invoice,
        conditions,
        rule.conditionsLogic
      );

      if (conditionsMatch) {
        // Apply actions (only if the field is not already set by a higher priority rule)
        if (actions.typeAchat && !updates.typeAchat) {
          updates.typeAchat = actions.typeAchat as "CAPEX" | "OPEX";
          autoFilledFieldsList.push("typeAchat");
        }
        if (actions.serviceConcerne && !updates.serviceConcerne) {
          updates.serviceConcerne = actions.serviceConcerne;
          autoFilledFieldsList.push("serviceConcerne");
        }
        if (actions.ventilationComptable && !updates.ventilationComptable) {
          updates.ventilationComptable = actions.ventilationComptable;
          autoFilledFieldsList.push("ventilationComptable");
        }
      }
    } catch (error) {
      console.error(`[AutomationEngine] Error processing rule ${rule.id}:`, error);
      // Continue with next rule on error
    }
  }

  // Add the list of auto-filled fields to the updates
  if (autoFilledFieldsList.length > 0) {
    updates.autoFilledFields = JSON.stringify(autoFilledFieldsList);
  }

  return updates;
}

/**
 * Apply automation rules to multiple invoices
 */
export async function applyAutomationRulesToBatch(
  userId: number,
  invoices: Invoice[]
): Promise<Map<number, Partial<Invoice>>> {
  const results = new Map<number, Partial<Invoice>>();

  for (const invoice of invoices) {
    const updates = await applyAutomationRules(userId, invoice);
    if (Object.keys(updates).length > 0) {
      results.set(invoice.id, updates);
    }
  }

  return results;
}