import { LogLevels, applyStringFormatting, createLogger } from '@aztec/foundation/log';

import type { AvmContext } from '../avm_context.js';
import { TypeTag } from '../avm_memory_types.js';
import { Opcode, OperandType } from '../serialization/instruction_serialization.js';
import { Addressing } from './addressing_mode.js';
import { Instruction } from './instruction.js';

export class DebugLog extends Instruction {
  static type: string = 'DEBUGLOG';
  static readonly opcode: Opcode = Opcode.DEBUGLOG;
  static readonly logger = createLogger('simulator:avm:debug_log');

  // Informs (de)serialization. See Instruction.deserialize.
  static readonly wireFormat: OperandType[] = [
    OperandType.UINT8, // Opcode
    OperandType.UINT8, // Indirect
    OperandType.UINT16, // level memory address
    OperandType.UINT16, // message memory address
    OperandType.UINT16, // fields memory address
    OperandType.UINT16, // fields size address
    OperandType.UINT16, // message size
  ];

  constructor(
    private addressingMode: number,
    private levelOffset: number,
    private messageOffset: number,
    private fieldsOffset: number,
    private fieldsSizeOffset: number,
    private messageSize: number,
  ) {
    super();
  }

  public async execute(context: AvmContext): Promise<void> {
    const memory = context.machineState.memory;
    const addressing = Addressing.fromWire(this.addressingMode);

    context.machineState.consumeGas(
      this.baseGasCost(addressing.indirectOperandsCount(), addressing.relativeOperandsCount()),
    );

    const operands = [this.levelOffset, this.messageOffset, this.fieldsOffset, this.fieldsSizeOffset];
    const [levelOffset, messageOffset, fieldsOffset, fieldsSizeOffset] = addressing.resolve(operands, memory);

    // DebugLog is a no-op except unless the config is set to collect debug logs.
    // Note that we still do address resolution and basic tag-checking (above)
    // To avoid a special-case in the witness generator and circuit.
    if (context.environment.config.collectDebugLogs) {
      memory.checkTag(TypeTag.UINT8, levelOffset);
      const levelNumber = memory.get(levelOffset).toNumber();
      memory.checkTag(TypeTag.UINT32, fieldsSizeOffset);
      const fieldsSize = memory.get(fieldsSizeOffset).toNumber();

      const memoryReads = 1 /* level */ + 1 /* fieldsSize */ + this.messageSize /* message */ + fieldsSize; /* fields */
      if (
        context.persistableState.getDebugLogMemoryReads() + memoryReads >
        context.environment.config.collectionLimits.maxDebugLogMemoryReads
      ) {
        // Regular error on purpose: this is not a recoverable error.
        throw new Error(
          `Max debug log memory reads exceeded: ${context.persistableState.getDebugLogMemoryReads() + memoryReads} > ${context.environment.config.collectionLimits.maxDebugLogMemoryReads}`,
        );
      }
      context.persistableState.writeDebugLogMemoryReads(memoryReads);

      const rawMessage = memory.getSlice(messageOffset, this.messageSize);
      const fields = memory.getSlice(fieldsOffset, fieldsSize);

      memory.checkTagsRange(TypeTag.UINT8, messageOffset, this.messageSize);
      memory.checkTagsRange(TypeTag.FIELD, fieldsOffset, fieldsSize);

      // Interpret str<N> = [u8; N] to string.
      const messageAsStr = rawMessage.map(field => String.fromCharCode(field.toNumber())).join('');

      if (!LogLevels[levelNumber]) {
        // Regular error on purpose: this is not a recoverable error.
        throw new Error(`Invalid debug log level: ${levelNumber}`);
      }

      const level = LogLevels[levelNumber];

      context.persistableState.writeDebugLog(
        context.environment.address,
        level,
        messageAsStr,
        fields.map(field => field.toFr()),
      );

      // Skips string formatting if the level is disabled.
      if (DebugLog.logger.isLevelEnabled(level)) {
        const formattedStr = applyStringFormatting(
          messageAsStr,
          fields.map(field => field.toFr()),
        );

        DebugLog.logger[level](formattedStr);
      }
    }
  }
}