"""
Cirq Compiler for BioQL

This module provides compilation of BioQL IR to Cirq quantum circuits.
"""

import datetime
import random
from typing import Any, Dict, List, Optional, Union

# Optional loguru import
try:
    from loguru import logger
except ImportError:
    import logging
    logger = logging.getLogger(__name__)

from bioql.ir import (
    AlignmentOperation,
    BioQLProgram,
    BioQLResult,
    DockingOperation,
    QuantumBackend,
    QuantumOptimizationOperation,
)
from .base import BaseCompiler, CompilationError, QuantumCircuitInterface

# Try to import Cirq with graceful fallback
try:
    import cirq
    CIRQ_AVAILABLE = True
except ImportError:
    logger.warning("Cirq not available, using mock implementation")
    CIRQ_AVAILABLE = False
    cirq = None


class CirqCircuitWrapper(QuantumCircuitInterface):
    """Wrapper for Cirq Circuit to implement our interface."""

    def __init__(self, num_qubits: int):
        if not CIRQ_AVAILABLE:
            raise CompilationError("Cirq not available")

        self.num_qubits = num_qubits
        self.qubits = [cirq.LineQubit(i) for i in range(num_qubits)]
        self.circuit = cirq.Circuit()
        self.measurements_added = set()

    def add_hadamard(self, qubit: int) -> None:
        self.circuit.append(cirq.H(self.qubits[qubit]))

    def add_pauli_x(self, qubit: int) -> None:
        self.circuit.append(cirq.X(self.qubits[qubit]))

    def add_pauli_y(self, qubit: int) -> None:
        self.circuit.append(cirq.Y(self.qubits[qubit]))

    def add_pauli_z(self, qubit: int) -> None:
        self.circuit.append(cirq.Z(self.qubits[qubit]))

    def add_cnot(self, control: int, target: int) -> None:
        self.circuit.append(cirq.CNOT(self.qubits[control], self.qubits[target]))

    def add_rotation_x(self, qubit: int, angle: float) -> None:
        self.circuit.append(cirq.rx(angle)(self.qubits[qubit]))

    def add_rotation_y(self, qubit: int, angle: float) -> None:
        self.circuit.append(cirq.ry(angle)(self.qubits[qubit]))

    def add_rotation_z(self, qubit: int, angle: float) -> None:
        self.circuit.append(cirq.rz(angle)(self.qubits[qubit]))

    def add_measurement(self, qubit: int, classical_bit: int) -> None:
        if qubit not in self.measurements_added:
            self.circuit.append(cirq.measure(self.qubits[qubit], key=f'q{qubit}'))
            self.measurements_added.add(qubit)

    def get_depth(self) -> int:
        return len(self.circuit)

    def get_gate_count(self) -> int:
        return len(list(self.circuit.all_operations()))

    def to_qasm(self) -> str:
        """Convert Cirq circuit to OpenQASM (simplified)."""
        qasm_lines = [
            "OPENQASM 2.0;",
            'include "qelib1.inc";',
            f"qreg q[{self.num_qubits}];",
            f"creg c[{len(self.measurements_added)}];"
        ]

        gate_count = 0
        for moment in self.circuit:
            for operation in moment:
                if isinstance(operation.gate, cirq.H):
                    qubit_idx = self.qubits.index(operation.qubits[0])
                    qasm_lines.append(f"h q[{qubit_idx}];")
                elif isinstance(operation.gate, cirq.X):
                    qubit_idx = self.qubits.index(operation.qubits[0])
                    qasm_lines.append(f"x q[{qubit_idx}];")
                elif isinstance(operation.gate, cirq.Y):
                    qubit_idx = self.qubits.index(operation.qubits[0])
                    qasm_lines.append(f"y q[{qubit_idx}];")
                elif isinstance(operation.gate, cirq.Z):
                    qubit_idx = self.qubits.index(operation.qubits[0])
                    qasm_lines.append(f"z q[{qubit_idx}];")
                elif isinstance(operation.gate, cirq.CNOT):
                    control_idx = self.qubits.index(operation.qubits[0])
                    target_idx = self.qubits.index(operation.qubits[1])
                    qasm_lines.append(f"cx q[{control_idx}],q[{target_idx}];")
                # Add other gates as needed
                gate_count += 1

        # Add measurements
        for i, qubit in enumerate(self.measurements_added):
            qasm_lines.append(f"measure q[{qubit}] -> c[{i}];")

        return "\n".join(qasm_lines)

    def get_cirq_circuit(self) -> "cirq.Circuit":
        """Get the underlying Cirq circuit."""
        return self.circuit


class CirqCompiler(BaseCompiler):
    """Cirq-specific compiler for BioQL programs."""

    def __init__(self):
        super().__init__(QuantumBackend.CIRQ)
        if not CIRQ_AVAILABLE:
            logger.warning("Cirq not available, some features will be limited")

    def compile_program(self, program: BioQLProgram) -> Union[Any, Dict[str, Any]]:
        """
        Compile a BioQL program into a Cirq Circuit.

        Args:
            program: BioQL program to compile

        Returns:
            Compiled Cirq Circuit or mock representation

        Raises:
            CompilationError: If compilation fails
        """
        try:
            self.logger.info(f"Compiling program {program.name} for Cirq")

            # Estimate number of qubits needed
            num_qubits = self._estimate_qubits_needed(program)
            self.logger.debug(f"Using {num_qubits} qubits")

            if CIRQ_AVAILABLE:
                # Create Cirq circuit wrapper
                circuit_wrapper = CirqCircuitWrapper(num_qubits)
            else:
                # Use mock implementation
                from .base import MockQuantumCircuit
                circuit_wrapper = MockQuantumCircuit(num_qubits)

            # Compile each operation
            for i, operation in enumerate(program.operations):
                self.logger.debug(f"Compiling operation {i}: {operation.operation_type}")

                if isinstance(operation, DockingOperation):
                    self._compile_docking_operation(operation, circuit_wrapper)
                elif isinstance(operation, AlignmentOperation):
                    self._compile_alignment_operation(operation, circuit_wrapper)
                elif isinstance(operation, QuantumOptimizationOperation):
                    self._compile_optimization_operation(operation, circuit_wrapper)
                else:
                    raise CompilationError(f"Unsupported operation type: {type(operation)}")

            # Add measurements for all qubits
            for i in range(num_qubits):
                circuit_wrapper.add_measurement(i, i)

            if CIRQ_AVAILABLE and isinstance(circuit_wrapper, CirqCircuitWrapper):
                compiled_circuit = circuit_wrapper.get_cirq_circuit()
                self.logger.success(f"Compiled circuit: {len(compiled_circuit)} moments, {circuit_wrapper.get_gate_count()} gates")
                return compiled_circuit
            else:
                # Return mock representation
                return {
                    "type": "mock_cirq_circuit",
                    "num_qubits": num_qubits,
                    "gates": getattr(circuit_wrapper, 'gates', []),
                    "measurements": getattr(circuit_wrapper, 'measurements', [])
                }

        except Exception as e:
            self.logger.error(f"Compilation failed: {e}")
            raise CompilationError(f"Failed to compile program: {e}")

    def execute(self, compiled_program: Union[Any, Dict[str, Any]], shots: int = 1000, program_id: Optional[str] = None) -> BioQLResult:
        """
        Execute a compiled Cirq program.

        Args:
            compiled_program: Compiled program (Cirq Circuit or mock)
            shots: Number of shots

        Returns:
            Execution results
        """
        start_time = datetime.datetime.utcnow()

        try:
            if CIRQ_AVAILABLE and hasattr(compiled_program, 'all_operations'):
                # Execute on Cirq
                result = self._execute_cirq_circuit(compiled_program, shots)
            else:
                # Mock execution
                result = self._execute_mock_circuit(compiled_program, shots)

            execution_time = (datetime.datetime.utcnow() - start_time).total_seconds()

            from uuid import uuid4
            return BioQLResult(
                program_id=program_id or uuid4(),
                status="success",
                results=result,
                execution_time=execution_time,
                shots_executed=shots,
                backend_used=QuantumBackend.CIRQ,
                execution_timestamp=start_time.isoformat(),
                version_info={"cirq": "simulated" if not CIRQ_AVAILABLE else "real"}
            )

        except Exception as e:
            execution_time = (datetime.datetime.utcnow() - start_time).total_seconds()
            self.logger.error(f"Execution failed: {e}")

            from uuid import uuid4
            return BioQLResult(
                program_id=program_id or uuid4(),
                status="failed",
                error_message=str(e),
                error_type=type(e).__name__,
                execution_time=execution_time,
                backend_used=QuantumBackend.CIRQ,
                execution_timestamp=start_time.isoformat()
            )

    def _execute_cirq_circuit(self, circuit: Any, shots: int) -> Dict[str, Any]:
        """Execute a Cirq circuit."""
        # Use Cirq simulator
        simulator = cirq.Simulator()

        # Run the circuit
        result = simulator.run(circuit, repetitions=shots)

        # Process results
        counts = {}
        measurements = result.measurements

        # Convert measurement results to count dictionary
        if measurements:
            # Get all measurement keys
            keys = sorted(measurements.keys())
            for i in range(shots):
                bit_string = ''.join(str(measurements[key][i][0]) for key in keys)
                counts[bit_string] = counts.get(bit_string, 0) + 1

        return {
            "counts": counts,
            "circuit_depth": len(circuit),
            "gate_count": len(list(circuit.all_operations())),
            "shots_requested": shots,
            "shots_executed": shots
        }

    def _execute_mock_circuit(self, circuit_data: Dict[str, Any], shots: int) -> Dict[str, Any]:
        """Execute a mock circuit (for when Cirq is not available)."""
        num_qubits = circuit_data.get("num_qubits", 4)

        # Generate mock results
        counts = {}
        for _ in range(shots):
            # Generate random bit string
            bit_string = ''.join(str(random.randint(0, 1)) for _ in range(num_qubits))
            counts[bit_string] = counts.get(bit_string, 0) + 1

        return {
            "counts": counts,
            "circuit_depth": len(circuit_data.get("gates", [])),
            "gate_count": len(circuit_data.get("gates", [])),
            "shots_requested": shots,
            "shots_executed": shots,
            "note": "Mock execution (Cirq not available)"
        }

    def _compile_docking_operation(
        self,
        operation: DockingOperation,
        circuit: QuantumCircuitInterface
    ) -> None:
        """Compile a docking operation into quantum gates."""
        self.logger.debug("Compiling docking operation for Cirq")

        # Encode receptor molecule (qubits 0-3)
        self._create_molecular_encoding_circuit(
            circuit, operation.receptor.data, 0, 4
        )

        # Encode ligand molecule (qubits 4-7)
        self._create_molecular_encoding_circuit(
            circuit, operation.ligand.data, 4, 4
        )

        # Create entanglement for docking interaction
        self._create_entangling_layer(circuit, list(range(8)))

        # Add variational circuit for pose optimization
        # Cirq-style parameterized circuit
        parameters = [
            operation.energy_threshold / 10.0,
            operation.num_poses / 100.0,
            1.5708,  # π/2
            0.7854   # π/4
        ]
        self._create_variational_layer(circuit, list(range(8)), parameters)

        # Add some Cirq-specific optimization
        self._add_cirq_specific_gates(circuit, list(range(8)))

    def _compile_alignment_operation(
        self,
        operation: AlignmentOperation,
        circuit: QuantumCircuitInterface
    ) -> None:
        """Compile an alignment operation into quantum gates."""
        self.logger.debug("Compiling alignment operation for Cirq")

        # Encode sequences
        seq1_data = operation.sequences[0].data[:20]
        seq2_data = operation.sequences[1].data[:20]

        self._create_molecular_encoding_circuit(circuit, seq1_data, 0, 4)
        self._create_molecular_encoding_circuit(circuit, seq2_data, 4, 4)

        # Quantum alignment circuit with Cirq-specific optimizations
        for i in range(4):
            circuit.add_cnot(i, i + 4)

        # Add scoring based on alignment parameters
        match_angle = operation.match_score * 3.14159 / 10
        gap_angle = abs(operation.gap_penalty) * 3.14159 / 10

        for i in range(8):
            circuit.add_rotation_y(i, match_angle)
            circuit.add_rotation_z(i, gap_angle)

        self._add_cirq_specific_gates(circuit, list(range(8)))

    def _compile_optimization_operation(
        self,
        operation: QuantumOptimizationOperation,
        circuit: QuantumCircuitInterface
    ) -> None:
        """Compile an optimization operation into quantum gates."""
        self.logger.debug("Compiling optimization operation for Cirq")

        num_vars = len(operation.variables)
        qubits_per_var = max(1, 8 // max(1, num_vars))

        # Encode optimization variables
        for i, variable in enumerate(operation.variables):
            start_qubit = i * qubits_per_var
            end_qubit = min(start_qubit + qubits_per_var, 8)

            # Initialize superposition
            for q in range(start_qubit, end_qubit):
                circuit.add_hadamard(q)

            # Variable-specific encoding
            if hasattr(variable.value, '__float__'):
                angle = float(variable.value) * 3.14159 / 100
                for q in range(start_qubit, end_qubit):
                    circuit.add_rotation_y(q, angle)

        # QAOA-inspired circuit for Cirq
        self._create_qaoa_layer(circuit, list(range(8)))
        self._add_cirq_specific_gates(circuit, list(range(8)))

    def _add_cirq_specific_gates(self, circuit: QuantumCircuitInterface, qubits: List[int]) -> None:
        """Add Cirq-specific optimizations and gates."""
        # Add some phase gates for better optimization
        for i in range(0, len(qubits), 2):
            if i + 1 < len(qubits):
                # Controlled-Z gates (natural in Cirq)
                circuit.add_cnot(qubits[i], qubits[i + 1])
                circuit.add_pauli_z(qubits[i + 1])
                circuit.add_cnot(qubits[i], qubits[i + 1])

    def _create_qaoa_layer(self, circuit: QuantumCircuitInterface, qubits: List[int]) -> None:
        """Create a QAOA-style layer optimized for Cirq."""
        # Cost layer
        for i in range(0, len(qubits) - 1, 2):
            circuit.add_cnot(qubits[i], qubits[i + 1])
            circuit.add_rotation_z(qubits[i + 1], 3.14159 / 4)
            circuit.add_cnot(qubits[i], qubits[i + 1])

        # Mixer layer
        for qubit in qubits:
            circuit.add_rotation_x(qubit, 3.14159 / 3)


# Export main class
__all__ = ["CirqCompiler", "CirqCircuitWrapper"]