from django.db import models
from django.contrib.auth import get_user_model
from django.urls import reverse_lazy

from .date_utils import after_30_days

User = get_user_model()


class Tag(models.Model):
    name = models.CharField(max_length=255, unique=True, db_index=True)

    class Meta:
        ordering = ['name']

    def __str__(self):
        return self.name


class Job(models.Model):
    CLOSED_REASON_FILLED = 'filled'
    CLOSED_REASON_NOT_FOUND = 'not-found'
    CLOSED_REASON_CANCELLED = 'cancelled'
    CLOSED_REASON_CHOICES = (
        (CLOSED_REASON_FILLED, "Job filled"),
        (CLOSED_REASON_CANCELLED, "Job Cancelled"),
        (CLOSED_REASON_NOT_FOUND, "Suitable candidate not found")
    )

    title = models.CharField(max_length=2055)
    description = models.TextField()
    tags = models.ManyToManyField(Tag, related_name="jobs")

    created = models.DateTimeField(auto_now_add=True)
    updated = models.DateTimeField(auto_now=True)
    expires = models.DateTimeField(default=after_30_days, editable=False)

    closed = models.BooleanField(default=False)
    close_reason = models.CharField(
        max_length=2055, choices=CLOSED_REASON_CHOICES, blank=True)

    posted_by = models.ForeignKey(
        User, related_name="jobs", on_delete=models.CASCADE)

    active = models.BooleanField(default=True)

    def renew(self):
        self.expires = after_30_days()
        self.save()

    def __str__(self):
        return self.title

    def get_absolute_url(self):
        return reverse_lazy("jobs:job_detail", args=[self.id])


class Question(models.Model):
    ''' A model to hold screening questions for a job post '''
    name = models.TextField('Question Title')
    job = models.ForeignKey(
        Job, related_name='questions', on_delete=models.CASCADE)

    def __str__(self):
        return self.name


class Application(models.Model):
    ''' A model representing applications to job '''

    applicant = models.ForeignKey(
        User, related_name="applications", on_delete=models.CASCADE)
    job = models.ForeignKey(
        Job, related_name="applications", on_delete=models.CASCADE)
    cover_letter = models.TextField(blank=True)

    created = models.DateTimeField(auto_now_add=True)

    class Meta:
        unique_together = ('applicant', 'job')

    def __str__(self):
        return "{0} - Job: {1}".format(self.applicant, self.job)


class Answer(models.Model):
    ''' a model to hold answers for screening questions by job applicants '''

    question = models.ForeignKey(
        Question, related_name='answers', on_delete=models.CASCADE)
    application = models.ForeignKey(
        Application, related_name='answers', on_delete=models.CASCADE
    )
    text = models.TextField()

    class Meta:
        unique_together = ('question', 'application')

    def __str__(self):
        return "Answer for : {0} - {1}".format(self.question, self.application)

class JobMessage(models.Model):
    """Basic user to user messaging app"""
    sender = models.ForeignKey(User, on_delete=models.CASCADE, related_name="sender")
    receiver = models.ForeignKey(User, on_delete=models.CASCADE, related_name="receiver")
    text = models.TextField()
    date = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return '{}, {}'.format(self.sender, self.text[:50])