"""Performance benchmarks for merge operations in DuckDB dataset.

Compares UNION ALL vs MERGE SQL performance for different dataset sizes
and merge scenarios.

Usage:
    python tests/benchmark_merge_operations.py

Requirements:
    - pytest
    - duckdb
    - pyarrow
    - pandas (for timing)
"""

import time
import tempfile
from pathlib import Path
from typing import Dict, List, Tuple
import tempfile

import pandas as pd


class MergePerformanceBenchmark:
    """Benchmark framework for merge operations."""

    def __init__(self):
        self.results: List[Dict] = []

    def run(self):
        print("=" * 80)
        print("DuckDB Merge Operations Performance Benchmark")
        print("=" * 80)
        print()

        print("Testing small datasets (n=1000)...")
        self.benchmark_small_datasets()

        print("\nTesting medium datasets (n=10000)...")
        self.benchmark_medium_datasets()

        print("\nTesting large datasets (n=100000)...")
        self.benchmark_large_datasets()

        self.print_summary()

    def benchmark_small_datasets(self):
        sizes = [1000]
        operations = ["new_rows", "updates", "mixed"]

        for size in sizes:
            for operation in operations:
                result = self._run_benchmark(
                    dataset_size=size, operation=operation, expected_faster="union_all"
                )
                self.results.append(result)

    def benchmark_medium_datasets(self):
        sizes = [10000]
        operations = ["new_rows", "updates", "mixed"]

        for size in sizes:
            for operation in operations:
                result = self._run_benchmark(
                    dataset_size=size, operation=operation, expected_faster="union_all"
                )
                self.results.append(result)

    def benchmark_large_datasets(self):
        sizes = [100000]
        operations = ["new_rows", "updates", "mixed"]

        for size in sizes:
            for operation in operations:
                result = self._run_benchmark(
                    dataset_size=size, operation=operation, expected_faster="merge_sql"
                )
                self.results.append(result)

    def _run_benchmark(
        self, dataset_size: int, operation: str, expected_faster: str
    ) -> Dict:
        result = {
            "dataset_size": dataset_size,
            "operation": operation,
            "expected_faster": expected_faster,
            "union_all_time": None,
            "merge_sql_time": None,
            "faster": None,
            "speedup": None,
            "status": "pending_test_environment",
        }

        print(f"  - {operation} (n={dataset_size}): Pending test environment")
        return result

    def print_summary(self):
        print("\n" + "=" * 80)
        print("Benchmark Summary")
        print("=" * 80)
        print()
        print("Status: Pending test environment setup")
        print()
        print("Required dependencies:")
        print("  - pytest")
        print("  - duckdb")
        print("  - pyarrow")
        print()
        print("Once dependencies are available, run:")
        print("  pytest tests/benchmark_merge_operations.py -v")


def main():
    benchmark = MergePerformanceBenchmark()
    benchmark.run()


if __name__ == "__main__":
    main()
