#!/usr/bin/python3

import collections
import math
import pickle
import sys
import time

from termcolor import colored

from . import db
from .action import parse
from .edits import classify_edits, clean_graph, edit_graph, get_edits_from_traces
from .graph import Node, graphviz
from .prolog.engine import PrologEngine
from .prolog.util import compose, decompose, map_vars, rename_vars, stringify
from .util import PQueue, Token, indent

# score a program (a list of lines) according to lines distribution
def score(program, lines):
    result = 1
    for line in program:
        line_normal = list(line)
        rename_vars(line_normal)
        line_normal = tuple(line_normal)
        result *= lines.get(line_normal, 0.01)

    if len(program) == 0 or result == 0:
        return 0.01
    return math.pow(result, 1/len(program))

# find a sequence of edits that fixes [code]
def fix(name, code, edits, timeout=30, debug=False):
    todo = PQueue()  # priority queue of candidate solutions
    done = set()     # set of already-analyzed solutions

    # Add a new candidate solution ([lines]+[rules]) to the priority queue.
    # This solution is generated by applying [step] with [cost] to [prev] task.
    def add_task(lines, rules, prev=None, step=None, cost=None):
        if prev is None:
            path = ()
            path_cost = 1.0
        else:
            path = tuple(list(prev[1]) + [step])
            path_cost = prev[2] * cost
        todo.push(((tuple(lines), tuple(rules)), path, path_cost), -path_cost)

    lines, rules = decompose(code)
    add_task(lines, rules)

    inserts, removes, changes = classify_edits(edits)
    start_time = time.monotonic()
    n_tested = 0
    while True:
        total_time = time.monotonic() - start_time
        if total_time > timeout:
            break

        task = todo.pop()
        if task == None:
            break

        (lines, rules), path, path_cost = task
        code = compose(lines, rules)
        if code in done:
            continue
        done.add(code)

        if debug:
            print('Cost {:.12f}'.format(path_cost))
            for line, (before, after) in path:
                print('line ' + str(line) + ':\t' + stringify(before) + ' → ' + stringify(after))

        # if the code is correct, we are done
        try:
            if test(name, code):
                return code, path, total_time, n_tested
        except:
            pass
        n_tested += 1

        # otherwise generate new solutions
        rule_no = 0
        for start, end in rules:
            rule = lines[start:end]
            rule_tokens = [t for line in rule for t in line]

            for line_idx in range(start, end):
                line = lines[line_idx]

                line_normal = list(line)
                rename_vars(line_normal)
                line_normal = tuple(line_normal)

                seen = False
                for (before, after), cost in changes.items():
                    if line_normal == before:
                        seen = True
                        mapping = map_vars(before, after, line, rule_tokens)
                        after_real = tuple([t if t.type != 'VARIABLE' else Token('VARIABLE', mapping[t.val]) for t in after])
                        new_lines = lines[:line_idx] + (after_real,) + lines[line_idx+1:]
                        new_step = ((rule_no, line_idx-start), (tuple(line), after_real))

                        add_task(new_lines, rules, prev=task, step=new_step, cost=cost)

                # if nothing could be done with this line, try removing it
                # (maybe try removing in any case?)
                if line_normal in removes.keys() or not seen:
                    new_lines = lines[:line_idx] + lines[line_idx+1:]
                    new_rules = []
                    for old_start, old_end in rules:
                        new_start, new_end = (old_start - (0 if old_start <= line_idx else 1),
                                              old_end - (0 if old_end <= line_idx else 1))
                        if new_end > new_start:
                            new_rules.append((new_start, new_end))
                    new_step = ((rule_no, line_idx-start), (tuple(line), ()))
                    new_cost = removes[line_normal] if line_normal in removes.keys() else 0.9

                    add_task(new_lines, new_rules, prev=task, step=new_step, cost=new_cost)

            # try adding a line to this rule… would need to distinguish between
            # head/body lines in transforms
            for after, cost in inserts.items():
                mapping = map_vars([], after, [], rule_tokens)
                after_real = [t if t.type != 'VARIABLE' else Token('VARIABLE', mapping[t.val]) for t in after]
                after_real = tuple(after_real)
                new_lines = lines[:end] + (after_real,) + lines[end:]
                new_rules = []
                for old_start, old_end in rules:
                    new_rules.append((old_start + (0 if old_start < end else 1),
                                      old_end + (0 if old_end < end else 1)))
                new_step = ((rule_no, end-start), ((), after_real))

                add_task(new_lines, new_rules, prev=task, step=new_step, cost=cost)
            rule_no += 1

        # try adding a new fact
        if len(rules) < 2:
            for after, cost in inserts.items():
                new_lines = lines + (after,)
                new_rules = rules + (((len(lines), len(lines)+1)),)
                new_step = ((len(new_rules)-1, 0), (tuple(), tuple(after)))

                add_task(new_lines, new_rules, prev=task, step=new_step, cost=cost)

    return '', [], total_time, n_tested

def print_hint(solution, steps, fix_time, n_tested):
    if solution:
        print(colored('Hint found! Tested {} programs in {:.1f} s.'.format(n_tested, fix_time), 'green'))
        print(colored(' Edits', 'blue'))
        for line, (before, after) in steps:
            print('  {}:\t{} → {}'.format(line, stringify(before), stringify(after)))
        print(colored(' Final version', 'blue'))
        print(indent(compose(*decompose(solution)), 2))
    else:
        print(colored('Hint not found! Tested {} programs in {:.1f} s.'.format(n_tested, fix_time), 'red'))

# Find official solutions to all problems.
def init_problems():
    names = {}
    codes = {}
    libraries = {}

    pids = db.get_problem_ids()
    for pid in pids:
        names[pid], codes[pid], libraries[pid] = db.get_problem(pid)

    return names, codes, libraries

# Submit code to Prolog server for testing.
def test(name, code):
    # TODO also load fact library and solved predicates
    engine = PrologEngine(code=code)
    result = engine.ask("run_tests({}, '{}')".format(name, engine.id))
    engine.destroy()
    return result['event'] == 'success'

if __name__ == '__main__':
    # Get problem id from commandline.
    if len(sys.argv) < 2:
        print('usage: ' + sys.argv[0] + ' <pid>')
        sys.exit(1)
    pid = int(sys.argv[1])

    names, codes, libraries = init_problems()

    # Analyze traces for this problem to get edits, submissions and queries.
    traces = db.get_traces(pid)
    edits, lines, submissions, queries = get_edits_from_traces(traces.values())

    # Find incorrect submissions.
    incorrect = []
    for submission, count in sorted(submissions.items()):
        if not test(names[pid], submission):
            # This incorrect submission appeared in [count] attempts.
            incorrect += [submission]*count

    # XXX only for testing
    try:
        done = pickle.load(open('status-'+str(pid)+'.pickle', 'rb'))
    except:
        done = []

    # test fix() on incorrect student submissions
    if len(sys.argv) >= 3 and sys.argv[2] == 'test':
        timeout = int(sys.argv[3]) if len(sys.argv) >= 4 else 10

        print('Fixing {}/{} programs (timeout={})…'.format(
            len([p for p in incorrect if p not in done]), len(incorrect), timeout))

        for i, program in enumerate(incorrect):
            if program in done:
                continue
            print(colored('Analyzing program {0}/{1}…'.format(i+1, len(incorrect)), 'yellow'))
            print(indent(compose(*decompose(program)), 2))

            solution, steps, fix_time, n_tested = fix(names[pid], program, edits, timeout=timeout)
            if solution:
                done.append(program)
            print_hint(solution, steps, fix_time, n_tested)
            print()

            pickle.dump(done, open('status-'+str(pid)+'.pickle', 'wb'))

        print('Found hints for ' + str(len(done)) + ' of ' + str(len(incorrect)) + ' incorrect programs')

    # print info for this problem
    elif len(sys.argv) >= 3 and sys.argv[2] == 'info':
        # with no additional arguments, print some stats
        if len(sys.argv) == 3:
            print('Problem {} ({}): {} edits in {} traces, fixed {}/{} ({}/{} unique)'.format(
                pid, colored(names[pid], 'yellow'),
                colored(str(len(edits)), 'yellow'), colored(str(len(traces)), 'yellow'),
                colored(str(len([p for p in incorrect if p in done])), 'yellow'),
                colored(str(len(incorrect)), 'yellow'),
                colored(str(len(set(done))), 'yellow'),
                colored(str(len(set(incorrect))), 'yellow')))
        else:
            if sys.argv[3] == 'users':
                print(' '.join([str(uid) for (pid, uid) in sorted(traces.keys())]))
            # print all observed edits and their costs
            elif sys.argv[3] == 'edits':
                inserts, removes, changes = classify_edits(edits)
                print('Inserts')
                for after, cost in sorted(inserts.items(), key=lambda x: x[1]):
                    print(' {:.2f}\t{}'.format(cost, stringify(after)))
                print('Removes')
                for before, cost in sorted(removes.items(), key=lambda x: x[1]):
                    print(' {:.2f}\t{}'.format(cost, stringify(before)))
                print('Changes')
                for (before, after), cost in sorted(changes.items(), key=lambda x: x[1]):
                    print(' {:.2f}\t{} → {}'.format(cost,
                                                   stringify(before if before else [('INVALID', 'ε')]),
                                                   stringify(after if after else [('INVALID', 'ε')])))
            # print all student submissions not (yet) corrected
            elif sys.argv[3] == 'unsolved':
                for p in sorted(set(incorrect)):
                    if p in done:
                        continue
                    print(indent(compose(*decompose(p)), 2))
                    print()
            # print all student queries and their counts
            elif sys.argv[3] == 'queries':
                for query, count in queries.most_common():
                    print('  ' + str(count) + '\t' + query)

    # Print the edit graph in graphviz dot syntax.
    elif len(sys.argv) == 4 and sys.argv[2] == 'graph':
        uid = int(sys.argv[3])
        actions = parse(traces[(pid, uid)])

        nodes, submissions, queries = edit_graph(actions)

        def position(node):
            return (node.data[1]*150, node.data[0]*-60)

        def label(node):
            return stringify(node.data[2])

        def node_attr(node):
            if node.ein and node.data[2] == node.ein[0].data[2]:
                return 'color="gray", shape="point"'
            return ''

        def edge_attr(a, b):
            if a.data[2] == b.data[2]:
                return 'arrowhead="none"'
            return ''

        graphviz_str = graphviz(nodes, pos=position, label=label,
                                node_attr=node_attr, edge_attr=edge_attr)
        print(graphviz_str)

    # run interactive loop
    else:
        while True:
            # read the program from stdin
            print('Enter program, end with empty line:')
            code = ''
            try:
                while True:
                    line = input()
                    if not line:
                        break
                    code += line + '\n'
            except EOFError:
                break

            # try finding a fix
            print(colored('Analyzing program…', 'yellow'))
            solution, steps, fix_time, n_tested = fix(names[pid], code, edits, debug=True)
            print_hint(solution, steps, fix_time, n_tested)