from django.db import models

CURRICULUM_CHOICES = [
    ("No curriculum", "No curriculum"),
    ("English", "English"),
    ("Scottish", "Scottish"),
]

AGE_RANGE_CHOICES = [
    ("Preschool (3-4yrs)", "Preschool (3-4yrs)"),
    ("Nursery (2-5yrs)", "Nursery (2-5yrs)"),
    ("Reception (4-5yrs)", "Reception (4-5yrs)"),
    ("Year 1 (5-6yrs)", "Year 1 (5-6yrs)"),
    ("Year 2 (6-7yrs)", "Year 2 (6-7yrs)"),
    ("Early Years (0-5yrs)", "Early Years (0-5yrs)"),
    ("Keystage 1 (5-7yrs)", "Keystage 1 (5-7yrs)"),
    ("Keystage 2 (7-11yrs)", "Keystage 2 (7-11yrs)"),
    ("Age not applicable", "Age not applicable"),
]

DESC_HELP_TEXT = """
    <strong>Markdown acceptable here!</strong>This is your opportunity to clearly explain what
    your resource is all about! It’s worth remembering that you are using the space to
    communicate to two different audiences. Firstly, think about what fellow teachers
    would like to know, such as exactly what the resource contains and how it could be used in
    the classroom. Secondly, the words you include on this page are also talking to internal and
    external search engines. External search engines, like Google, show the first 155 characters
    of the resource description, so make sure you take advantage
    of these characters by using lots of relevant keywords as part of an enticing pitch.
"""


# Create your models here.
class Resource(models.Model):
    name = models.CharField(max_length=255, null=False)
    thumbnail_filenames = models.JSONField(
        null=False,
        verbose_name="Thumbnail filenames",
        default=list,
    )
    resource_type = models.ForeignKey("ResourceType", on_delete=models.CASCADE)
    main_resource_category = models.ForeignKey(
        "ResourceCategory",
        on_delete=models.CASCADE,
        null=False,
        related_name="main_resource_category",
    )
    additional_resource_category = models.ForeignKey(
        "ResourceCategory",
        on_delete=models.CASCADE,
        null=True,
        blank=True,
        related_name="additional_resource_category",
    )
    description = models.TextField(
        max_length=5000,
        null=False,
        blank=False,
        help_text=DESC_HELP_TEXT,
    )
    card_description = models.TextField(
        max_length=1000,
        blank=True,
        default="",
        help_text=("If you enter text here, it will be used in the 'card' "
                   "description box on the home page. Max 1000 characters."),
    )
    age_range = models.CharField(
        max_length=20,
        null=False,
        default="5-7",
        blank=False,
        choices=AGE_RANGE_CHOICES,
    )
    curriculum = models.CharField(
        max_length=20,
        default="English",
        blank=True,
        null=True,
        choices=[
            ("No curriculum", "No curriculum"),
            ("English", "English"),
            ("Scottish", "Scottish"),
        ],
    )
    feature_slot = models.IntegerField(
        choices=((1, 1), (2, 2), (3, 3)), unique=True, null=True, blank=True, default=0,
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    def __str__(self):
        return self.name

    def get_pdf_file_names(self):
        return [p.file_name for p in self.pdf_resources.all()]

    def get_pdf_snapshot_file_names(self):
        rs = self.pdf_resources.all()
        sh = [sh for sh in rs.values_list("pdf_page_snapshots__file_name", flat=True)]
        return [s for s in sh if s]


class ResourceType(models.Model):
    name = models.CharField(max_length=255, null=False)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    def __str__(self):
        return self.name


class ResourceCategory(models.Model):
    name = models.CharField(max_length=255, null=False)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    colour_css_class = models.CharField(max_length=56, blank=True, null=True)

    class Meta:
        verbose_name_plural = "Resource Categories"

    def __str__(self):
        return self.name


class PDFResource(models.Model):
    resource = models.ForeignKey(
        "Resource",
        on_delete=models.CASCADE,
        null=False,
        related_name="pdf_resources",
    )
    file_name = models.CharField(max_length=255, null=False)
    file_size = models.IntegerField(null=False)

    class Meta:
        unique_together = ("resource", "file_name")

    def __str__(self):
        return self.resource.name

    def snapshot_file_names(self):
        return [f.file_name for f in self.pdf_page_snapshots.all()]


class PDFPageSnapshot(models.Model):
    name = models.CharField(max_length=255, null=False)
    file_name = models.CharField(max_length=255, null=False)
    pdf_file = models.ForeignKey(
        "PDFResource",
        on_delete=models.CASCADE,
        null=False,
        related_name="pdf_page_snapshots",
    )

    def __str__(self):
        return self.name