import frappe
from lms.www.utils import get_common_context, redirect_to_lesson
from lms.lms.utils import get_lesson_url, has_course_moderator_role, is_instructor, redirect_to_courses_list
from frappe.utils import cstr, flt

def get_context(context):
    get_common_context(context)

    chapter_index = frappe.form_dict.get("chapter")
    lesson_index = frappe.form_dict.get("lesson")
    lesson_number = f"{chapter_index}.{lesson_index}"
    context.lesson_index = lesson_index
    context.chapter = frappe.db.get_value("Chapter Reference", {
        "idx": chapter_index,
        "parent": context.course.name
        }, "chapter")

    if not chapter_index or not lesson_index:
        if context.batch:
            index_ = get_lesson_index(context.course, context.batch, frappe.session.user) or "1.1"
        else:
            index_ = "1.1"
        redirect_to_lesson(context.course, index_)

    context.lesson = get_current_lesson_details(lesson_number, context)
    instructor = is_instructor(context.course.name)
    context.show_lesson = context.membership or (context.lesson and context.lesson.include_in_preview) or instructor or has_course_moderator_role()

    if not context.lesson:
        context.lesson = frappe._dict()

    if frappe.form_dict.get("edit"):
        if not instructor and not has_course_moderator_role():
            redirect_to_courses_list()
        context.lesson.edit_mode = True
    else:
        neighbours = get_neighbours(lesson_number, context.lessons)
        context.next_url = get_url(neighbours["next"], context.course)
        context.prev_url = get_url(neighbours["prev"], context.course)

    meta_info = context.lesson.title + " - " + context.course.title if context.lesson.title else "New Lesson"
    context.metatags = {
        "title": meta_info,
        "keywords": meta_info,
        "description": meta_info
    }

    context.page_extensions = get_page_extensions(context)
    context.page_context = {
        "course": context.course.name,
        "batch": context.get("batch") and context.batch.name,
        "lesson": context.lesson.name if context.lesson.name else "New Lesson",
        "is_member": context.membership is not None
    }


def get_current_lesson_details(lesson_number, context):
    details_list = list(filter(lambda x: cstr(x.number) == lesson_number, context.lessons))

    if not len(details_list):
        if frappe.form_dict.get("edit"):
            return None
        else:
            redirect_to_lesson(context.course)

    lesson_info = details_list[0]
    lesson_info.body = lesson_info.body.replace("\"", "'")
    return lesson_info


def get_url(lesson_number, course):
    return get_lesson_url(course.name, lesson_number) and get_lesson_url(course.name, lesson_number) + course.query_parameter


def get_lesson_index(course, batch, user):
    lesson = batch.get_current_lesson(user)
    return lesson and course.get_lesson_index(lesson)


def get_page_extensions(context):
    default_value = ["lms.plugins.PageExtension"]
    classnames = frappe.get_hooks("lms_lesson_page_extensions") or default_value
    extensions = [frappe.get_attr(name)() for name in classnames]
    for e in extensions:
        e.set_context(context)
    return extensions


def get_neighbours(current, lessons):
    current = flt(current)
    numbers = sorted(lesson.number for lesson in lessons)
    index = numbers.index(current)
    return {
            "prev": numbers[index-1] if index-1 >= 0 else None,
            "next": numbers[index+1] if index+1 < len(numbers) else None
        }