# IfcOpenShell - IFC toolkit and geometry engine
# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
#
# This file is part of IfcOpenShell.
#
# IfcOpenShell is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# IfcOpenShell is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.

import datetime
import ifcopenshell.util.date
from functools import lru_cache


def derive_date(task, attribute_name, date=None, is_earliest=False, is_latest=False):
    if task.TaskTime:
        current_date = (
            ifcopenshell.util.date.ifc2datetime(getattr(task.TaskTime, attribute_name))
            if getattr(task.TaskTime, attribute_name)
            else ""
        )
        if current_date:
            return current_date
    for subtask in get_all_nested_tasks(task):
        current_date = derive_date(
            subtask,
            attribute_name,
            date=date,
            is_earliest=is_earliest,
            is_latest=is_latest,
        )
        if is_earliest:
            if current_date and (date is None or current_date < date):
                date = current_date
        if is_latest:
            if current_date and (date is None or current_date > date):
                date = current_date
    return date


def derive_calendar(task):
    calendar = [
        rel.RelatingControl
        for rel in task.HasAssignments or []
        if rel.is_a("IfcRelAssignsToControl")
        and rel.RelatingControl.is_a("IfcWorkCalendar")
    ]
    if calendar:
        return calendar[0]
    for rel in task.Nests or []:
        return derive_calendar(rel.RelatingObject)


def count_working_days(start, finish, calendar):
    result = 0
    current_date = datetime.date(start.year, start.month, start.day)
    finish_date = datetime.date(finish.year, finish.month, finish.day)
    while current_date <= finish_date:
        if (
            calendar
            and calendar.WorkingTimes
            and is_working_day(current_date, calendar)
        ):
            result += 1
        elif not calendar or not is_calendar_applicable(current_date, calendar):
            result += 1
        current_date += datetime.timedelta(days=1)
    return result


def get_start_or_finish_date(
    start, duration, duration_type, calendar, date_type="FINISH"
):
    if not duration.days:
        # Typically a milestone will have zero duration, so the start == finish
        return start
    # We minus 1 because the start day itself is counted as a day
    months = int(getattr(duration, "months", 0))
    years = int(getattr(duration, "years", 0))
    total_duration = duration.days + months * 30 + years * 12 * 30
    duration = datetime.timedelta(days=total_duration - 1)

    if date_type == "START":
        duration = -duration
    result = offset_date(start, duration, duration_type, calendar)
    if date_type == "START":
        return datetime.datetime.combine(result, datetime.time(9))
    return datetime.datetime.combine(result, datetime.time(17))


def offset_date(start, duration, duration_type, calendar):
    current_date = start
    months = getattr(duration, "months", 0)
    years = getattr(duration, "years", 0)

    abs_duration = abs((duration.days + months * 30 + years * 12 * 30))
    date_offset = datetime.timedelta(days=1 if duration.days > 0 else -1)
    while abs_duration > 0:
        if duration_type == "ELAPSEDTIME" or not is_calendar_applicable(
            current_date, calendar
        ):
            abs_duration -= 1
        elif is_working_day(current_date, calendar):
            abs_duration -= 1
        current_date += date_offset
    if duration.days > 0:
        current_date = get_soonest_working_day(current_date, duration_type, calendar)
    else:
        current_date = get_recent_working_day(current_date, duration_type, calendar)
    return current_date


def get_soonest_working_day(start, duration_type, calendar):
    if duration_type == "ELAPSEDTIME" or not is_calendar_applicable(start, calendar):
        return start
    while not is_working_day(start, calendar):
        if not is_calendar_applicable(start, calendar):
            break
        start += datetime.timedelta(days=1)
    return start


def get_recent_working_day(start, duration_type, calendar):
    if duration_type == "ELAPSEDTIME" or not is_calendar_applicable(start, calendar):
        return start
    while not is_working_day(start, calendar):
        if not is_calendar_applicable(start, calendar):
            break
        start -= datetime.timedelta(days=1)
    return start


@lru_cache(maxsize=None)
def is_working_day(day, calendar):
    is_working_day = False
    for work_time in calendar.WorkingTimes or []:
        if is_work_time_applicable_to_day(work_time, day):
            is_working_day = True
            break
    if not is_working_day:
        return is_working_day
    for work_time in calendar.ExceptionTimes or []:
        if is_work_time_applicable_to_day(work_time, day):
            is_working_day = False
            break
    return is_working_day


@lru_cache(maxsize=None)
def is_calendar_applicable(day, calendar):
    if not calendar or not calendar.WorkingTimes:
        return False
    is_applicable = False
    for work_time in calendar.WorkingTimes or []:
        if is_day_in_work_time(day, work_time):
            is_applicable = True
            break
    return is_applicable


def is_day_in_work_time(day, work_time):
    is_day_in_work_time = True
    if isinstance(day, datetime.datetime):
        day = datetime.date(day.year, day.month, day.day)
    if work_time.Start:
        start = ifcopenshell.util.date.ifc2datetime(work_time.Start)
        if day > start:
            is_day_in_work_time = True
        else:
            is_day_in_work_time = False
    if work_time.Finish:
        finish = ifcopenshell.util.date.ifc2datetime(work_time.Finish)
        if day < finish:
            is_day_in_work_time = True
        else:
            is_day_in_work_time = False
    return is_day_in_work_time


def is_work_time_applicable_to_day(work_time, day):
    if not is_day_in_work_time(day, work_time):
        return False
    if not work_time.RecurrencePattern:
        return True

    if isinstance(day, datetime.datetime):
        day = datetime.date(day.year, day.month, day.day)
    recurrence = work_time.RecurrencePattern
    if recurrence.RecurrenceType == "DAILY":
        if not recurrence.Interval and not recurrence.Occurrences:
            return True
        if not work_time.Start:
            return False
        return False  # TODO
    elif recurrence.RecurrenceType == "WEEKLY":
        if not recurrence.Interval and not recurrence.Occurrences:
            return (day.weekday() + 1) in recurrence.WeekdayComponent
        if not work_time.Start:
            return False
        return False  # TODO
    elif recurrence.RecurrenceType == "MONTHLY_BY_DAY_OF_MONTH":
        if not recurrence.Interval and not recurrence.Occurrences:
            return day.day in recurrence.DayComponent
        return False  # TODO
    elif recurrence.RecurrenceType == "MONTHLY_BY_POSITION":
        if not recurrence.Interval and not recurrence.Occurrences:
            return (day.weekday() + 1) in recurrence.WeekdayComponent and math.floor(
                day.day / 7
            ) + 1 == recurrence["Position"]
        return False  # TODO
    elif recurrence.RecurrenceType == "YEARLY_BY_DAY_OF_MONTH":
        if not recurrence.Interval and not recurrence.Occurrences:
            return (
                day.month in recurrence.MonthComponent
                and day.day in recurrence.DayComponent
            )
        return False  # TODO
    elif recurrence.RecurrenceType == "YEARLY_BY_POSITION":
        if not recurrence.Interval and not recurrence.Occurrences:
            return (
                day.month in recurrence.MonthComponent
                and (day.weekday() + 1) in recurrence.WeekdayComponent
                and math.floor(day.day / 7) + 1 == recurrence.Position
            )
        return False  # TODO


def get_task_work_schedule(task):
    parent_task = get_parent_task(task)
    if parent_task:
        return get_task_work_schedule(parent_task) or get_task_work_schedule(task)
    else:
        for rel in task.HasAssignments:
            if rel.is_a("IfcRelAssignsToControl") and rel.RelatingControl.is_a(
                "IfcWorkSchedule"
            ):
                return rel.RelatingControl
        return None


def get_nested_tasks(task):
    return [object for rel in task.IsNestedBy for object in rel.RelatedObjects]


def get_parent_task(task):
    return (
        task.Nests[0].RelatingObject
        if task.Nests and task.Nests[0].RelatingObject.is_a("IfcTask")
        else None
    )


def get_all_nested_tasks(task):
    for nested_task in get_nested_tasks(task):
        yield nested_task
        yield from get_all_nested_tasks(nested_task)


def get_work_schedule_tasks(work_schedule):
    tasks = []
    for root_task in get_root_tasks(work_schedule):
        nested_tasks = get_all_nested_tasks(root_task)
        tasks.extend(nested_tasks)
    return tasks


def get_root_tasks(work_schedule):
    return [
        obj
        for rel in work_schedule.Controls
        for obj in rel.RelatedObjects
        if obj.is_a("IfcTask")
    ]


def get_root_tasks_ids(work_schedule):
    return [
        obj.id()
        for rel in work_schedule.Controls
        for obj in rel.RelatedObjects
        if obj.is_a("IfcTask")
    ]


def guess_date_range(work_schedule):
    earliest = None
    latest = None
    root_tasks = get_root_tasks(work_schedule)
    tasks_with_assignements = []
    for task in root_tasks:
        if has_task_outputs(task) or has_task_inputs(task):
            tasks_with_assignements.append(task)
        for sub_task in get_all_nested_tasks(task):
            if has_task_outputs(sub_task) or has_task_inputs(sub_task):
                tasks_with_assignements.append(sub_task)

    for task in tasks_with_assignements:
        derived_start = derive_date(task, "ScheduleStart", is_earliest=True)
        derived_finish = derive_date(task, "ScheduleFinish", is_latest=True)
        if derived_start and (not earliest or derived_start < earliest):
            earliest = derived_start
        if derived_finish and (not latest or derived_finish > latest):
            latest = derived_finish
    return earliest, latest


def get_direct_task_outputs(task):
    return [
        rel.RelatingProduct
        for rel in task.HasAssignments
        if rel.is_a("IfcRelAssignsToProduct")
    ]


def get_task_outputs(task, is_deep=False):
    if not is_deep:
        return get_direct_task_outputs(task)
    else:
        return [
            output
            for nested_task in get_all_nested_tasks(task)
            for output in get_direct_task_outputs(nested_task)
        ]


def get_task_inputs(task, is_deep=False):
    if not is_deep:
        return [
            object
            for rel in task.OperatesOn
            if rel.is_a("IfcRelAssignsToProcess")
            for object in rel.RelatedObjects
            if object.is_a("IfcProduct")
        ]
    else:
        return [
            output
            for nested_task in get_all_nested_tasks(task)
            for output in [
                object
                for rel in nested_task.OperatesOn
                if rel.is_a("IfcRelAssignsToProcess")
                for object in rel.RelatedObjects
                if object.is_a("IfcProduct")
            ]
        ]


def get_task_resources(task, is_deep=False):
    if not is_deep:
        return [
            object
            for rel in task.OperatesOn
            if rel.is_a("IfcRelAssignsToProcess")
            for object in rel.RelatedObjects
            if object.is_a("IfcResource")
        ]
    else:
        return [
            resource
            for nested_task in get_all_nested_tasks(task)
            for resource in [
                object
                for rel in nested_task.OperatesOn
                if rel.is_a("IfcRelAssignsToProcess")
                for object in rel.RelatedObjects
                if object.is_a("IfcResource")
            ]
        ]


def has_task_outputs(task):
    return len(get_task_outputs(task)) > 0


def has_task_inputs(task):
    return len(get_task_inputs(task)) > 0


def get_tasks_for_product(product, schedule=None):
    """
    Get all tasks assigned to or referenced by the given product.

    Args:
        product: An object that is assigned tasks or references tasks.
        schedule: An optional string representing the schedule name to filter tasks by.

    Returns:
        A tuple of two lists:
        - The first list contains all tasks assigned to the product.
        - The second list contains all tasks referenced by the product that are part of the given schedule.
    """
    inputs = [
        assignement.RelatingProcess
        for assignement in product.HasAssignments
        if assignement.is_a("IfcRelAssignsToProcess")
        and assignement.RelatingProcess.is_a("IfcTask")
    ]
    outputs = [
        obj
        for ref in product.ReferencedBy
        if ref.is_a("IfcRelAssignsToProduct")
        for obj in ref.RelatedObjects
        if obj.is_a("IfcTask")
    ]

    if schedule:
        inputs = [
            task
            for task in inputs
            if get_task_work_schedule(task).id() == schedule.id()
        ]
        outputs = [
            task
            for task in outputs
            if get_task_work_schedule(task).id() == schedule.id()
        ]

    return inputs, outputs