#!/usr/bin/env python3
#
# Script to manipulate CSV files.
#
# Example:
# ./scripts/code.py lfs.o lfs_util.o -q -o lfs.code.csv
# ./scripts/data.py lfs.o lfs_util.o -q -o lfs.data.csv
# ./scripts/csv.py lfs.code.csv lfs.data.csv -q -o lfs.csv
# ./scripts/csv.py -Y lfs.csv -f code=code_size,data=data_size
#
# Copyright (c) 2022, The littlefs authors.
# SPDX-License-Identifier: BSD-3-Clause
#

# prevent local imports
__import__('sys').path.pop(0)

import collections as co
import csv
import functools as ft
import itertools as it
import math as mt
import os
import re


# supported merge operations
#
# this is a terrible way to express these
#
OPS = {
    'sum':     lambda xs: sum(xs[1:], start=xs[0]),
    'prod':    lambda xs: mt.prod(xs[1:], start=xs[0]),
    'min':     min,
    'max':     max,
    'avg':     lambda xs: RFloat(sum(float(x) for x in xs) / len(xs)),
    'stddev':  lambda xs: (
            lambda avg: RFloat(
                mt.sqrt(sum((float(x) - avg)**2 for x in xs) / len(xs)))
        )(sum(float(x) for x in xs) / len(xs)),
    'gmean':   lambda xs: RFloat(mt.prod(float(x) for x in xs)**(1/len(xs))),
    'gstddev': lambda xs: (
        lambda gmean: RFloat(
            mt.exp(mt.sqrt(
                    sum(mt.log(float(x)/gmean)**2 for x in xs)
                        / len(xs)))
                if gmean else mt.inf)
        )(mt.prod(float(x) for x in xs)**(1/len(xs))),
}


# integer fields
class RInt(co.namedtuple('RInt', 'x')):
    __slots__ = ()
    def __new__(cls, x=0):
        if isinstance(x, RInt):
            return x
        if isinstance(x, str):
            try:
                x = int(x, 0)
            except ValueError:
                # also accept +-∞ and +-inf
                if re.match('^\s*\+?\s*(?:∞|inf)\s*$', x):
                    x = mt.inf
                elif re.match('^\s*-\s*(?:∞|inf)\s*$', x):
                    x = -mt.inf
                else:
                    raise
        assert isinstance(x, int) or mt.isinf(x), x
        return super().__new__(cls, x)

    def __str__(self):
        if self.x == mt.inf:
            return '∞'
        elif self.x == -mt.inf:
            return '-∞'
        else:
            return str(self.x)

    def __int__(self):
        assert not mt.isinf(self.x)
        return self.x

    def __float__(self):
        return float(self.x)

    none = '%7s' % '-'
    def table(self):
        return '%7s' % (self,)

    def diff(self, other):
        new = self.x if self else 0
        old = other.x if other else 0
        diff = new - old
        if diff == +mt.inf:
            return '%7s' % '+∞'
        elif diff == -mt.inf:
            return '%7s' % '-∞'
        else:
            return '%+7d' % diff

    def ratio(self, other):
        new = self.x if self else 0
        old = other.x if other else 0
        if mt.isinf(new) and mt.isinf(old):
            return 0.0
        elif mt.isinf(new):
            return +mt.inf
        elif mt.isinf(old):
            return -mt.inf
        elif not old and not new:
            return 0.0
        elif not old:
            return +mt.inf
        else:
            return (new-old) / old

    def __add__(self, other):
        return self.__class__(self.x + other.x)

    def __sub__(self, other):
        return self.__class__(self.x - other.x)

    def __mul__(self, other):
        return self.__class__(self.x * other.x)

# float fields
class RFloat(co.namedtuple('RFloat', 'x')):
    __slots__ = ()
    def __new__(cls, x=0.0):
        if isinstance(x, RFloat):
            return x
        if isinstance(x, str):
            try:
                x = float(x)
            except ValueError:
                # also accept +-∞ and +-inf
                if re.match('^\s*\+?\s*(?:∞|inf)\s*$', x):
                    x = mt.inf
                elif re.match('^\s*-\s*(?:∞|inf)\s*$', x):
                    x = -mt.inf
                else:
                    raise
        assert isinstance(x, float), x
        return super().__new__(cls, x)

    def __str__(self):
        if self.x == mt.inf:
            return '∞'
        elif self.x == -mt.inf:
            return '-∞'
        else:
            return '%.1f' % self.x

    def __float__(self):
        return float(self.x)

    none = RInt.none
    table = RInt.table

    def diff(self, other):
        new = self.x if self else 0
        old = other.x if other else 0
        diff = new - old
        if diff == +mt.inf:
            return '%7s' % '+∞'
        elif diff == -mt.inf:
            return '%7s' % '-∞'
        else:
            return '%+7.1f' % diff

    ratio = RInt.ratio
    __add__ = RInt.__add__
    __sub__ = RInt.__sub__
    __mul__ = RInt.__mul__

# fractional fields, a/b
class RFrac(co.namedtuple('RFrac', 'a,b')):
    __slots__ = ()
    def __new__(cls, a=0, b=None):
        if isinstance(a, RFrac) and b is None:
            return a
        if isinstance(a, str) and b is None:
            a, b = a.split('/', 1)
        if b is None:
            b = a
        return super().__new__(cls, RInt(a), RInt(b))

    def __str__(self):
        return '%s/%s' % (self.a, self.b)

    def __float__(self):
        return float(self.a)

    none = '%11s' % '-'
    def table(self):
        return '%11s' % (self,)

    def notes(self):
        t = self.a.x/self.b.x if self.b.x else 1.0
        return ['∞%' if t == +mt.inf
                else '-∞%' if t == -mt.inf
                else '%.1f%%' % (100*t)]

    def diff(self, other):
        new_a, new_b = self if self else (RInt(0), RInt(0))
        old_a, old_b = other if other else (RInt(0), RInt(0))
        return '%11s' % ('%s/%s' % (
                new_a.diff(old_a).strip(),
                new_b.diff(old_b).strip()))

    def ratio(self, other):
        new_a, new_b = self if self else (RInt(0), RInt(0))
        old_a, old_b = other if other else (RInt(0), RInt(0))
        new = new_a.x/new_b.x if new_b.x else 1.0
        old = old_a.x/old_b.x if old_b.x else 1.0
        return new - old

    def __add__(self, other):
        return self.__class__(self.a + other.a, self.b + other.b)

    def __sub__(self, other):
        return self.__class__(self.a - other.a, self.b - other.b)

    def __mul__(self, other):
        return self.__class__(self.a * other.a, self.b + other.b)

    def __eq__(self, other):
        self_a, self_b = self if self.b.x else (RInt(1), RInt(1))
        other_a, other_b = other if other.b.x else (RInt(1), RInt(1))
        return self_a * other_b == other_a * self_b

    def __ne__(self, other):
        return not self.__eq__(other)

    def __lt__(self, other):
        self_a, self_b = self if self.b.x else (RInt(1), RInt(1))
        other_a, other_b = other if other.b.x else (RInt(1), RInt(1))
        return self_a * other_b < other_a * self_b

    def __gt__(self, other):
        return self.__class__.__lt__(other, self)

    def __le__(self, other):
        return not self.__gt__(other)

    def __ge__(self, other):
        return not self.__lt__(other)

# available types
TYPES = co.OrderedDict([
    ('int',   RInt),
    ('float', RFloat),
    ('frac',  RFrac)
])


def openio(path, mode='r', buffering=-1):
    # allow '-' for stdin/stdout
    if path == '-':
        if 'r' in mode:
            return os.fdopen(os.dup(sys.stdin.fileno()), mode, buffering)
        else:
            return os.fdopen(os.dup(sys.stdout.fileno()), mode, buffering)
    else:
        return open(path, mode, buffering)

def collect(csv_paths, renames=[], defines=[]):
    # collect results from CSV files
    fields = []
    results = []
    for path in csv_paths:
        try:
            with openio(path) as f:
                reader = csv.DictReader(f, restval='')
                fields.extend(
                        k for k in reader.fieldnames
                            if k not in fields)
                for r in reader:
                    # apply any renames
                    if renames:
                        # make a copy so renames can overlap
                        r_ = {}
                        for new_k, old_k in renames:
                            if old_k in r:
                                r_[new_k] = r[old_k]
                        r.update(r_)

                    # filter by matching defines
                    if not all(k in r and r[k] in vs for k, vs in defines):
                        continue

                    results.append(r)
        except FileNotFoundError:
            pass

    return fields, results

def infer(fields_, results,
        by=None,
        fields=None,
        types={},
        ops={},
        renames=[],
        defines=[]):
    # if by not specified, guess it's anything not in fields/renames/defines
    if by is None:
        by = [k for k in fields_
                if k not in (fields or [])
                    and not any(k == old_k for _, old_k in renames)
                    and not any(k == k_ for k_, _ in defines)]

    # if fields not specified, guess it's anything not in by/renames/defines
    if fields is None:
        fields = [k for k in fields_
                if k not in (by or [])
                    and not any(k == old_k for _, old_k in renames)
                    and not any(k == k_ for k_, _ in defines)]

    # deduplicate by/fields
    by = list(co.OrderedDict.fromkeys(by).keys())
    fields = list(co.OrderedDict.fromkeys(fields).keys())

    # find best type for all fields
    types_ = {}
    for k in fields:
        if k in types:
            types_[k] = types[k]
        else:
            for t in TYPES.values():
                for r in results:
                    if k in r and r[k].strip():
                        try:
                            t(r[k])
                        except ValueError:
                            break
                else:
                    types_[k] = t
                    break
            else:
                print("error: no type matches field %r?" % k,
                        file=sys.stderr)
                sys.exit(-1)
    types = types_

    # does folding change the type?
    types_ = {}
    for k, t in types.items():
        types_[k] = ops.get(k, OPS['sum'])([t()]).__class__


    # create result class
    def __new__(cls, **r):
        return cls.__mro__[1].__new__(cls,
                **{k: r.get(k, '') for k in by},
                **{k: r[k] if k in r and isinstance(r[k], tuple)
                        else ([types[k](r[k])], 1) if k in r
                        else ([], 0)
                    for k in fields})

    def __add__(self, other):
        # reuse lists if possible
        def extend(a, b):
            if len(a[0]) == a[1]:
                a[0].extend(b[0][:b[1]])
                return (a[0], a[1] + b[1])
            else:
                return (a[0][:a[1]] + b[0][:b[1]], a[1] + b[1])

        return self.__class__(
                **{k: getattr(self, k) for k in by},
                **{k: extend(
                        object.__getattribute__(self, k),
                        object.__getattribute__(other, k))
                    for k in fields})

    def __getattribute__(self, k):
        if k in fields:
            v = object.__getattribute__(self, k)
            if v[1]:
                return ops.get(k, OPS['sum'])(v[0][:v[1]])
            else:
                return None
        return object.__getattribute__(self, k)

    return type('Result', (co.namedtuple('Result', by + fields),), {
        '__slots__': (),
        '__new__': __new__,
        '__add__': __add__,
        '__getattribute__': __getattribute__,
        '_by': by,
        '_fields': fields,
        '_sort': fields,
        '_types': types_,
    })


def fold(Result, results, by=None, defines=[]):
    if by is None:
        by = Result._by

    for k in it.chain(by or [], (k for k, _ in defines)):
        if k not in Result._by and k not in Result._fields:
            print("error: could not find field %r?" % k,
                    file=sys.stderr)
            sys.exit(-1)

    # filter by matching defines
    if defines:
        results_ = []
        for r in results:
            if all(getattr(r, k) in vs for k, vs in defines):
                results_.append(r)
        results = results_

    # organize results into conflicts
    folding = co.OrderedDict()
    for r in results:
        name = tuple(getattr(r, k) for k in by)
        if name not in folding:
            folding[name] = []
        folding[name].append(r)

    # merge conflicts
    folded = []
    for name, rs in folding.items():
        folded.append(sum(rs[1:], start=rs[0]))

    return folded

def table(Result, results, diff_results=None, *,
        by=None,
        fields=None,
        sort=None,
        summary=False,
        all=False,
        percent=False,
        **_):
    all_, all = all, __builtins__.all

    if by is None:
        by = Result._by
    if fields is None:
        fields = Result._fields
    types = Result._types

    # fold again
    results = fold(Result, results, by=by)
    if diff_results is not None:
        diff_results = fold(Result, diff_results, by=by)

    # organize by name
    table = {
            ','.join(str(getattr(r, k) or '') for k in by): r
                for r in results}
    diff_table = {
            ','.join(str(getattr(r, k) or '') for k in by): r
                for r in diff_results or []}
    names = [name
            for name in table.keys() | diff_table.keys()
            if diff_results is None
                or all_
                or any(
                    types[k].ratio(
                            getattr(table.get(name), k, None),
                            getattr(diff_table.get(name), k, None))
                        for k in fields)]

    # sort again, now with diff info, note that python's sort is stable
    names.sort()
    if diff_results is not None:
        names.sort(
                key=lambda n: tuple(
                    types[k].ratio(
                            getattr(table.get(n), k, None),
                            getattr(diff_table.get(n), k, None))
                        for k in fields),
                reverse=True)
    if sort:
        for k, reverse in reversed(sort):
            names.sort(
                    key=lambda n: tuple(
                        (getattr(table[n], k),)
                                if getattr(table.get(n), k, None) is not None
                                else ()
                            for k in (
                                [k] if k else [
                                    k for k in Result._sort
                                        if k in fields])),
                    reverse=reverse ^ (not k or k in Result._fields))


    # build up our lines
    lines = []

    # header
    header = ['%s%s' % (
                ','.join(by),
                ' (%d added, %d removed)' % (
                        sum(1 for n in table if n not in diff_table),
                        sum(1 for n in diff_table if n not in table))
                    if diff_results is not None and not percent else '')
            if not summary else '']
    if diff_results is None:
        for k in fields:
            header.append(k)
    elif percent:
        for k in fields:
            header.append(k)
    else:
        for k in fields:
            header.append('o'+k)
        for k in fields:
            header.append('n'+k)
        for k in fields:
            header.append('d'+k)
    lines.append(header)

    # entry helper
    def table_entry(name, r, diff_r=None):
        entry = [name]
        if diff_results is None:
            for k in fields:
                entry.append(
                        (getattr(r, k).table(),
                                getattr(getattr(r, k), 'notes', lambda: [])())
                            if getattr(r, k, None) is not None
                            else types[k].none)
        elif percent:
            for k in fields:
                entry.append(
                        (getattr(r, k).table()
                                if getattr(r, k, None) is not None
                                else types[k].none,
                            (lambda t: ['+∞%'] if t == +mt.inf
                                    else ['-∞%'] if t == -mt.inf
                                    else ['%+.1f%%' % (100*t)])(
                                types[k].ratio(
                                    getattr(r, k, None),
                                    getattr(diff_r, k, None)))))
        else:
            for k in fields:
                entry.append(getattr(diff_r, k).table()
                        if getattr(diff_r, k, None) is not None
                        else types[k].none)
            for k in fields:
                entry.append(getattr(r, k).table()
                        if getattr(r, k, None) is not None
                        else types[k].none)
            for k in fields:
                entry.append(
                        (types[k].diff(
                                getattr(r, k, None),
                                getattr(diff_r, k, None)),
                            (lambda t: ['+∞%'] if t == +mt.inf
                                    else ['-∞%'] if t == -mt.inf
                                    else ['%+.1f%%' % (100*t)] if t
                                    else [])(
                                types[k].ratio(
                                    getattr(r, k, None),
                                    getattr(diff_r, k, None)))))
        return entry

    # entries
    if not summary:
        for name in names:
            r = table.get(name)
            if diff_results is None:
                diff_r = None
            else:
                diff_r = diff_table.get(name)
            lines.append(table_entry(name, r, diff_r))

    # total
    r = next(iter(fold(Result, results, by=[])), None)
    if diff_results is None:
        diff_r = None
    else:
        diff_r = next(iter(fold(Result, diff_results, by=[])), None)
    lines.append(table_entry('TOTAL', r, diff_r))

    # homogenize
    lines = [
            [x if isinstance(x, tuple) else (x, []) for x in line]
                for line in lines]

    # find the best widths, note that column 0 contains the names and is
    # handled a bit differently
    widths = co.defaultdict(lambda: 7, {0: 23})
    notes = co.defaultdict(lambda: 0)
    for line in lines:
        for i, x in enumerate(line):
            widths[i] = max(widths[i], ((len(x[0])+1+4-1)//4)*4-1)
            notes[i] = max(notes[i], 1+2*len(x[1])+sum(len(n) for n in x[1]))

    # print our table
    for line in lines:
        print('%-*s  %s' % (
                widths[0], line[0][0],
                ' '.join('%*s%-*s' % (
                        widths[i], x[0],
                        notes[i], ' (%s)' % ', '.join(x[1]) if x[1] else '')
                    for i, x in enumerate(line[1:], 1))))


def main(csv_paths, *,
        by=None,
        fields=None,
        defines=[],
        sort=None,
        **args):
    # separate out renames
    renames = list(it.chain.from_iterable(
            ((k, v) for v in vs)
                for k, vs in it.chain(by or [], fields or [])))
    if by is not None:
        by = [k for k, _ in by]
    if fields is not None:
        fields = [k for k, _ in fields]

    # figure out types
    types = {}
    for t in TYPES.keys():
        for k in args.get(t, []):
            if k in types:
                print("error: conflicting type for field %r?" % k,
                        file=sys.stderr)
                sys.exit(-1)
            types[k] = TYPES[t]
    # rename types?
    if renames:
        types_ = {}
        for new_k, old_k in renames:
            if old_k in types:
                types_[new_k] = types[old_k]
        types.update(types_)

    # figure out merge operations
    ops = {}
    for o in OPS.keys():
        for k in args.get(o, []):
            if k in ops:
                print("error: conflicting op for field %r?" % k,
                        file=sys.stderr)
                sys.exit(-1)
            ops[k] = OPS[o]
    # rename ops?
    if renames:
        ops_ = {}
        for new_k, old_k in renames:
            if old_k in ops:
                ops_[new_k] = ops[old_k]
        ops.update(ops_)

    if by is None and fields is None:
        print("error: needs --by or --fields to figure out fields",
                file=sys.stderr)
        sys.exit(-1)

    # use is just an alias
    if args.get('use'):
        csv_paths = csv_paths + [args['use']]

    # find CSV files
    fields_, results = collect(csv_paths, renames, defines)

    # homogenize
    Result = infer(fields_, results,
            by=by,
            fields=fields,
            types=types,
            ops=ops,
            renames=renames,
            defines=defines)
    results_ = []
    for r in results:
        if not any(k in r and r[k].strip()
                for k in Result._fields):
            continue
        try:
            results_.append(Result(**{
                    k: r[k] for k in Result._by + Result._fields
                        if k in r and r[k].strip()}))
        except TypeError:
            pass
    results = results_

    # fold
    results = fold(Result, results, by=by, defines=defines)

    # sort, note that python's sort is stable
    results.sort()
    if sort:
        for k, reverse in reversed(sort):
            results.sort(
                    key=lambda r: tuple(
                        (getattr(r, k),) if getattr(r, k) is not None else ()
                            for k in ([k] if k else Result._sort)),
                    reverse=reverse ^ (not k or k in Result._fields))

    # write results to CSV
    if args.get('output'):
        with openio(args['output'], 'w') as f:
            writer = csv.DictWriter(f, Result._by + Result._fields)
            writer.writeheader()
            for r in results:
                # note we need to go through getattr to resolve lazy fields
                writer.writerow({
                        k: getattr(r, k)
                            for k in Result._by + Result._fields})

    # find previous results?
    if args.get('diff'):
        _, diff_results = collect([args['diff']], renames, defines)
        diff_results_ = []
        for r in diff_results:
            if not any(k in r and r[k].strip()
                    for k in Result._fields):
                continue
            try:
                diff_results_.append(Result(**{
                        k: r[k] for k in Result._by + Result._fields
                            if k in r and r[k].strip()}))
            except TypeError:
                pass
        diff_results = diff_results_

        # fold
        diff_results = fold(Result, diff_results, by=by, defines=defines)

    # print table
    if not args.get('quiet'):
        table(Result, results,
                diff_results if args.get('diff') else None,
                by=by,
                fields=fields,
                sort=sort,
                **args)


if __name__ == "__main__":
    import argparse
    import sys
    parser = argparse.ArgumentParser(
            description="Script to manipulate CSV files.",
            allow_abbrev=False)
    parser.add_argument(
            'csv_paths',
            nargs='*',
            help="Input *.csv files.")
    parser.add_argument(
            '-q', '--quiet',
            action='store_true',
            help="Don't show anything, useful with -o.")
    parser.add_argument(
            '-o', '--output',
            help="Specify CSV file to store results.")
    parser.add_argument(
            '-u', '--use',
            help="Don't parse anything, use this CSV file.")
    parser.add_argument(
            '-d', '--diff',
            help="Specify CSV file to diff against.")
    parser.add_argument(
            '-a', '--all',
            action='store_true',
            help="Show all, not just the ones that changed.")
    parser.add_argument(
            '-p', '--percent',
            action='store_true',
            help="Only show percentage change, not a full diff.")
    parser.add_argument(
            '-b', '--by',
            action='append',
            type=lambda x: (
                lambda k, vs=None: (
                    k.strip(),
                    tuple(v.strip() for v in vs.split(','))
                        if vs is not None else ())
                )(*x.split('=', 1)),
            help="Group by this field. Can rename fields with "
                "new_name=old_name.")
    parser.add_argument(
            '-f', '--field',
            dest='fields',
            action='append',
            type=lambda x: (
                lambda k, vs=None: (
                    k.strip(),
                    tuple(v.strip() for v in vs.split(','))
                        if vs is not None else ())
                )(*x.split('=', 1)),
            help="Show this field. Can rename fields with "
                "new_name=old_name.")
    parser.add_argument(
            '-D', '--define',
            dest='defines',
            action='append',
            type=lambda x: (
                lambda k, vs: (
                    k.strip(),
                    {v.strip() for v in vs.split(',')})
                )(*x.split('=', 1)),
            help="Only include results where this field is this value. May "
                "include comma-separated options.")
    class AppendSort(argparse.Action):
        def __call__(self, parser, namespace, value, option):
            if namespace.sort is None:
                namespace.sort = []
            namespace.sort.append((value, True if option == '-S' else False))
    parser.add_argument(
            '-s', '--sort',
            nargs='?',
            action=AppendSort,
            help="Sort by this field.")
    parser.add_argument(
            '-S', '--reverse-sort',
            nargs='?',
            action=AppendSort,
            help="Sort by this field, but backwards.")
    parser.add_argument(
            '-Y', '--summary',
            action='store_true',
            help="Only show the total.")
    parser.add_argument(
            '--int',
            action='append',
            help="Treat these fields as ints.")
    parser.add_argument(
            '--float',
            action='append',
            help="Treat these fields as floats.")
    parser.add_argument(
            '--frac',
            action='append',
            help="Treat these fields as fractions.")
    parser.add_argument(
            '--sum',
            action='append',
            help="Add these fields (the default).")
    parser.add_argument(
            '--prod',
            action='append',
            help="Multiply these fields.")
    parser.add_argument(
            '--min',
            action='append',
            help="Take the minimum of these fields.")
    parser.add_argument(
            '--max',
            action='append',
            help="Take the maximum of these fields.")
    parser.add_argument(
            '--avg', '--mean',
            action='append',
            help="Average these fields.")
    parser.add_argument(
            '--stddev',
            action='append',
            help="Find the standard deviation of these fields.")
    parser.add_argument(
            '--gmean',
            action='append',
            help="Find the geometric mean of these fields.")
    parser.add_argument(
            '--gstddev',
            action='append',
            help="Find the geometric standard deviation of these fields.")
    sys.exit(main(**{k: v
            for k, v in vars(parser.parse_intermixed_args()).items()
            if v is not None}))