# Copyright 2021 The IREE Authors
#
# Licensed under the Apache License v2.0 with LLVM Exceptions.
# See https://llvm.org/LICENSE.txt for license information.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

from abc import ABC, abstractmethod
from dataclasses import dataclass
from typing import Any, Callable, Dict, Generic, List, Optional, Sequence, Tuple, TypeVar, Union
import pathlib
import dataclasses
import json
import urllib.parse
import markdown_strings as md
import math

from common.benchmark_definition import BenchmarkResults, CompilationInfo, CompilationResults
from common.benchmark_thresholds import BENCHMARK_THRESHOLDS, COMPILATION_TIME_THRESHOLDS, TOTAL_DISPATCH_SIZE_THRESHOLDS, BenchmarkThreshold, ThresholdUnit

GetMetricFunc = Callable[[Any], Tuple[int, Optional[int]]]
GetTableRowFunc = Callable[[str, Any], Tuple]

PERFBOARD_SERIES_PREFIX = "https://perf.iree.dev/serie?IREE?"
BENCHMARK_RESULTS_HEADERS = [
    "Benchmark Name",
    "Average Latency (ms)",
    "Median Latency (ms)",
    "Latency Standard Deviation (ms)",
]
COMPILATION_TIME_SERIES_SUFFIX = "compilation:module:compilation-time"
TOTAL_DISPATCH_SIZE_SERIES_SUFFIX = "compilation:module:component-size:total-dispatch-size"


@dataclass
class AggregateBenchmarkLatency:
  """An object for describing aggregate latency numbers for a benchmark."""
  mean_time: int
  median_time: int
  stddev_time: int
  # The average latency time for the base commit to compare against.
  base_mean_time: Optional[int] = None


@dataclass(frozen=True)
class CompilationMetrics:
  """An object for describing the summary of statistics and the reference."""
  compilation_info: CompilationInfo
  compilation_time_ms: int
  total_dispatch_component_bytes: int
  base_compilation_time_ms: Optional[int] = None
  base_total_dispatch_component_bytes: Optional[int] = None


T = TypeVar("T")


class MetricsToTableMapper(ABC, Generic[T]):
  """Abstract class to help map benchmark metrics to table.

    It contains a set of methods to help table generator get the required
    information for a metric. For example, extract the current and base metric
    value, the metric thresholds, the table header of the metrics, ...
  """

  @abstractmethod
  def update_base_value(self, obj: T, base_value: Any) -> T:
    """Sets the base value and returns the updated metric object."""
    raise NotImplementedError()

  @abstractmethod
  def get_current_and_base_value(self, obj: T) -> Tuple[int, Optional[int]]:
    """Returns the current and base (can be None) value."""
    raise NotImplementedError()

  @abstractmethod
  def get_series_name(self, name: str) -> str:
    """Returns the dashboard series name."""
    raise NotImplementedError()

  @abstractmethod
  def get_unit(self) -> str:
    """Returns the unit of the metric value."""
    raise NotImplementedError()

  @abstractmethod
  def get_table_header(self) -> str:
    """Returns the header of the table."""
    raise NotImplementedError()

  @staticmethod
  @abstractmethod
  def get_metric_thresholds() -> Sequence[BenchmarkThreshold]:
    raise NotImplementedError()

  @staticmethod
  @abstractmethod
  def get_table_title() -> str:
    raise NotImplementedError()


class CompilationTimeToTable(MetricsToTableMapper[CompilationMetrics]):
  """Helper to map CompilationMetrics to compilation time column."""

  def update_base_value(self, compile_metrics: CompilationMetrics,
                        base_value: Any) -> CompilationMetrics:
    return dataclasses.replace(compile_metrics,
                               base_compilation_time_ms=base_value)

  def get_current_and_base_value(
      self, compile_metrics: CompilationMetrics) -> Tuple[int, Optional[int]]:
    return (compile_metrics.compilation_time_ms,
            compile_metrics.base_compilation_time_ms)

  def get_series_name(self, name: str) -> str:
    return f"{name} [{COMPILATION_TIME_SERIES_SUFFIX}]"

  def get_unit(self) -> str:
    return "ms"

  def get_table_header(self) -> str:
    return f"Compilation Time ({self.get_unit()})"

  @staticmethod
  def get_metric_thresholds() -> Sequence[BenchmarkThreshold]:
    return COMPILATION_TIME_THRESHOLDS

  @staticmethod
  def get_table_title() -> str:
    return "Compilation Times"


class TotalDispatchSizeToTable(MetricsToTableMapper[CompilationMetrics]):
  """Helper to map CompilationMetrics to total dispatch size column."""

  def update_base_value(self, compile_metrics: CompilationMetrics,
                        base_value: Any) -> CompilationMetrics:
    return dataclasses.replace(compile_metrics,
                               base_total_dispatch_component_bytes=base_value)

  def get_current_and_base_value(
      self, compile_metrics: CompilationMetrics) -> Tuple[int, Optional[int]]:
    return (compile_metrics.total_dispatch_component_bytes,
            compile_metrics.base_total_dispatch_component_bytes)

  def get_series_name(self, name: str) -> str:
    return f"{name} [{TOTAL_DISPATCH_SIZE_SERIES_SUFFIX}]"

  def get_unit(self) -> str:
    return "bytes"

  def get_table_header(self) -> str:
    return f"Total Dispatch Size ({self.get_unit()})"

  @staticmethod
  def get_metric_thresholds() -> Sequence[BenchmarkThreshold]:
    return TOTAL_DISPATCH_SIZE_THRESHOLDS

  @staticmethod
  def get_table_title() -> str:
    return "Total Dispatch Sizes"


COMPILATION_METRICS_TO_TABLE_MAPPERS: List[
    MetricsToTableMapper[CompilationMetrics]] = [
        CompilationTimeToTable(),
        TotalDispatchSizeToTable(),
    ]


def aggregate_all_benchmarks(
    benchmark_files: Sequence[pathlib.Path],
    expected_pr_commit: Optional[str] = None,
    verbose: bool = False) -> Dict[str, AggregateBenchmarkLatency]:
  """Aggregates all benchmarks in the given files.

  Args:
  - benchmark_files: A list of JSON files, each can be decoded as a
    BenchmarkResults.
  - expected_pr_commit: An optional Git commit SHA to match against.

  Returns:
  - A dict of benchmark names to AggregateBenchmarkLatency numbers.
  """

  aggregate_results = {}

  for benchmark_file in benchmark_files:
    file_results = BenchmarkResults.from_json_str(benchmark_file.read_text())

    if ((expected_pr_commit is not None) and
        (file_results.commit != expected_pr_commit)):
      raise ValueError("Inconsistent pull request commit")

    for benchmark_index in range(len(file_results.benchmarks)):
      benchmark_case = file_results.benchmarks[benchmark_index]

      # Make sure each benchmark has a unique name.
      name = str(benchmark_case.benchmark_info)
      if name in aggregate_results:
        raise ValueError(f"Duplicated benchmarks: {name}")

      # Now scan all benchmark iterations and find the aggregate results.
      mean_time = file_results.get_aggregate_time(benchmark_index, "mean")
      median_time = file_results.get_aggregate_time(benchmark_index, "median")
      stddev_time = file_results.get_aggregate_time(benchmark_index, "stddev")

      aggregate_results[name] = AggregateBenchmarkLatency(
          mean_time, median_time, stddev_time)

  return aggregate_results


def collect_all_compilation_metrics(
    compile_stats_files: Sequence[pathlib.Path],
    expected_pr_commit: Optional[str] = None) -> Dict[str, CompilationMetrics]:
  """Collects all compilation statistics in the given files.

    Args:
      compile_stats_files: A list of JSON files, each can be decoded as a
        CompilationResults.
      expected_pr_commit: An optional Git commit SHA to match against.

    Returns:
      A dict of benchmark names to CompilationMetrics.
  """
  compile_metrics = {}

  for compile_stats_file in compile_stats_files:
    with compile_stats_file.open("r") as f:
      file_results = CompilationResults.from_json_object(json.load(f))

    if ((expected_pr_commit is not None) and
        (file_results.commit != expected_pr_commit)):
      raise ValueError("Inconsistent pull request commit")

    for compile_stats in file_results.compilation_statistics:
      component_sizes = compile_stats.module_component_sizes
      name = str(compile_stats.compilation_info)
      compile_metrics[name] = CompilationMetrics(
          compilation_info=compile_stats.compilation_info,
          compilation_time_ms=compile_stats.compilation_time_ms,
          total_dispatch_component_bytes=component_sizes.
          total_dispatch_component_bytes)

  return compile_metrics


def _make_series_link(name: str, series: Optional[str] = None) -> str:
  """Add link to the given benchmark name.

    Args:
      name: the text to show on the link.
      series: the dashboard series name. Use name if None.
  """
  if series is None:
    series = name
  url = PERFBOARD_SERIES_PREFIX + urllib.parse.quote(series, safe="()[]@,")
  return md.link(name, url)


def _add_header_and_get_markdown_table(headers: Sequence[str],
                                       rows: Sequence[Tuple],
                                       size_cut: Optional[int] = None) -> str:
  """Generates a markdown table with headers.

  Args:
    headers: list of table headers.
    rows: list of rows. Each row is a tuple with the same length as headers.
    size_cut: If not None, only show the top N results for each table.
  """

  total_size = len(rows)
  if size_cut is not None:
    rows = rows[0:size_cut]

  columns = [[header] for header in headers]
  for row in rows:
    for column, item in zip(columns, row):
      column.append(item)

  table_str = md.table(columns)
  if size_cut is not None and size_cut < total_size:
    table_str += "\n\n"
    table_str += md.italics(
        f"[Top {size_cut} out of {total_size} results showed]")
  return table_str


T = TypeVar("T")


def _categorize_on_single_metric(
    metrics_map: Dict[str, T],
    metric_func: GetMetricFunc,
    thresholds: Sequence[BenchmarkThreshold],
    metric_unit: str,
) -> Tuple[Dict[str, T], Dict[str, T], Dict[str, T], Dict[str, T]]:
  """Categorize the metrics object into regressed, improved, similar, and the
    raw group (the group with no base to compare to).

    Args:
      metrics_map: map of (name, metrics object).
      metric_func: the function returns current and base value of the metric.
      thresholds: list of threshold settings to match for categorizing.
    Returns:
      A tuple of (regressed, improved, similar, raw) groups.
  """

  regressed_map = {}
  improved_map = {}
  similar_map = {}
  raw_map = {}
  for name, metrics_obj in metrics_map.items():
    current, base = metric_func(metrics_obj)
    if base is None:
      raw_map[name] = metrics_obj
      continue

    similar_threshold = None
    for threshold in thresholds:
      if threshold.regex.match(name):
        similar_threshold = threshold
        break
    if similar_threshold is None:
      raise ValueError(f"No matched threshold setting for: {name}")

    if similar_threshold.unit == ThresholdUnit.PERCENTAGE:
      ratio = abs(current - base) / base * 100
    elif similar_threshold.unit.value == metric_unit:
      ratio = abs(current - base)
    else:
      raise ValueError(
          f"Mismatch between metric unit '{metric_unit}' and threshold unit '{similar_threshold.unit.value}'"
      )

    if ratio <= similar_threshold.threshold:
      similar_map[name] = metrics_obj
    elif current > base:
      regressed_map[name] = metrics_obj
    else:
      improved_map[name] = metrics_obj

  return (regressed_map, improved_map, similar_map, raw_map)


def _get_fixed_point_str(value: Union[int, float], digits=3) -> str:
  if isinstance(value, int) or value.is_integer():
    return str(math.floor(value))
  return f"{{:.{digits}f}}".format(value)


def _get_compare_text(current: float, base: Optional[int]) -> str:
  """Generates the text of comparison between current and base value. Returns
    the current value if the base value is None.
  """
  # If base is None, don't need to do compare.
  if base is None:
    return f"{_get_fixed_point_str(current)}"

  ratio = abs(current - base) / base
  direction = "↑" if current > base else ("↓" if current < base else "")
  return f"{_get_fixed_point_str(current)} (vs. {_get_fixed_point_str(base)}, {ratio:.2%}{direction})"


def _sort_benchmarks_and_get_table(benchmarks: Dict[str,
                                                    AggregateBenchmarkLatency],
                                   size_cut: Optional[int] = None) -> str:
  """Sorts all benchmarks according to the improvement/regression ratio and
    returns a markdown table for it.

    Args:
      benchmarks_map: map of (name, benchmark object).
      size_cut: If not None, only show the top N results for each table.
  """
  sorted_rows = []
  for name, benchmark in benchmarks.items():
    current = benchmark.mean_time / 1e6
    base = benchmark.base_mean_time / 1e6
    ratio = abs(current - base) / base
    str_mean = _get_compare_text(current, base)
    clickable_name = _make_series_link(name)
    sorted_rows.append(
        (ratio, (clickable_name, str_mean,
                 f"{_get_fixed_point_str(benchmark.median_time / 1e6)}",
                 f"{_get_fixed_point_str(benchmark.stddev_time / 1e6)}")))
  sorted_rows.sort(key=lambda row: row[0], reverse=True)

  return _add_header_and_get_markdown_table(
      headers=BENCHMARK_RESULTS_HEADERS,
      rows=[row[1] for row in sorted_rows],
      size_cut=size_cut)


def categorize_benchmarks_into_tables(benchmarks: Dict[
    str, AggregateBenchmarkLatency],
                                      size_cut: Optional[int] = None) -> str:
  """Splits benchmarks into regressed/improved/similar/raw categories and
    returns their markdown tables.

    If size_cut is None, the table includes regressed/improved/similar/raw
    categories; otherwise, the table includes regressed/improved/raw categories.

    Args:
      benchmarks: A dictionary of benchmark names to its aggregate info.
      size_cut: If not None, only show the top N results for each table.
  """
  regressed, improved, similar, raw = _categorize_on_single_metric(
      benchmarks, lambda results: (results.mean_time, results.base_mean_time),
      BENCHMARK_THRESHOLDS, "ns")

  tables = []
  if regressed:
    tables.append(md.header("Regressed Latencies 🚩", 3))
    tables.append(_sort_benchmarks_and_get_table(regressed, size_cut))
  if improved:
    tables.append(md.header("Improved Latencies 🎉", 3))
    tables.append(_sort_benchmarks_and_get_table(improved, size_cut))
  # If we want to abbreviate, similar results won't be interesting.
  if similar and size_cut is None:
    tables.append(md.header("Similar Latencies", 3))
    tables.append(_sort_benchmarks_and_get_table(similar, size_cut))
  if raw:
    tables.append(md.header("Raw Latencies", 3))
    raw_list = [
        (_make_series_link(k), f"{_get_fixed_point_str(v.mean_time / 1e6)}",
         f"{_get_fixed_point_str(v.median_time / 1e6)}",
         f"{_get_fixed_point_str(v.stddev_time / 1e6)}")
        for k, v in raw.items()
    ]
    tables.append(
        _add_header_and_get_markdown_table(BENCHMARK_RESULTS_HEADERS,
                                           raw_list,
                                           size_cut=size_cut))
  return "\n\n".join(tables)


def _sort_metrics_objects_and_get_table(metrics_objs: Dict[str, T],
                                        mapper: MetricsToTableMapper[T],
                                        headers: Sequence[str],
                                        size_cut: Optional[int] = None) -> str:
  """Sorts all metrics objects according to the improvement/regression ratio and
    returns a markdown table for it.

    Args:
      metrics_objs: map of (name, metrics object). All objects must contain base
        value.
      mapper: MetricsToTableMapper for metrics_objs.
      headers: list of table headers.
      size_cut: If not None, only show the top N results for each table.
  """
  sorted_rows = []
  for name, metrics_obj in metrics_objs.items():
    current, base = mapper.get_current_and_base_value(metrics_obj)
    if base is None:
      raise AssertionError("Base can't be None for sorting.")
    ratio = abs(current - base) / base
    sorted_rows.append((ratio, (
        _make_series_link(name, mapper.get_series_name(name)),
        _get_compare_text(current, base),
    )))
  sorted_rows.sort(key=lambda row: row[0], reverse=True)

  return _add_header_and_get_markdown_table(
      headers=headers, rows=[row[1] for row in sorted_rows], size_cut=size_cut)


def categorize_compilation_metrics_into_tables(
    compile_metrics_map: Dict[str, CompilationMetrics],
    size_cut: Optional[int] = None) -> str:
  """Splits compilation metrics into regressed/improved/all categories
    and returns their markdown tables.

    If size_cut is None, the table includes regressed/improved/all categories;
    otherwise, the table includes regressed/improved categories.

    Args:
      compile_metrics_map: A dictionary of benchmark names to its compilation
        metrics.
      size_cut: If not None, only show the top N results for each table.
  """

  tables = []
  for mapper in COMPILATION_METRICS_TO_TABLE_MAPPERS:
    regressed, improved, _, _ = _categorize_on_single_metric(
        compile_metrics_map, mapper.get_current_and_base_value,
        mapper.get_metric_thresholds(), mapper.get_unit())

    table_title = mapper.get_table_title()
    table_header = mapper.get_table_header()
    if regressed:
      tables.append(md.header(f"Regressed {table_title} 🚩", 3))
      tables.append(
          _sort_metrics_objects_and_get_table(regressed, mapper,
                                              ["Benchmark Name", table_header],
                                              size_cut))
    if improved:
      tables.append(md.header(f"Improved {table_title} 🎉", 3))
      tables.append(
          _sort_metrics_objects_and_get_table(improved, mapper,
                                              ["Benchmark Name", table_header],
                                              size_cut))

  # If we want to abbreviate, similar results won't be interesting.
  if size_cut is None and compile_metrics_map:
    tables.append(md.header("All Compilation Metrics", 3))
    headers = ["Benchmark Name"] + [
        mapper.get_table_header()
        for mapper in COMPILATION_METRICS_TO_TABLE_MAPPERS
    ]
    rows = []
    for name, metrics in compile_metrics_map.items():
      row = [name]
      for mapper in COMPILATION_METRICS_TO_TABLE_MAPPERS:
        current, base = mapper.get_current_and_base_value(metrics)
        row.append(
            _make_series_link(_get_compare_text(current, base),
                              mapper.get_series_name(name)))
      rows.append(tuple(row))

    tables.append(
        _add_header_and_get_markdown_table(headers, rows, size_cut=size_cut))

  return "\n\n".join(tables)