import re

import semver
from django.db import models
from django.core.validators import RegexValidator

from membershipworks.models import Member, Flag as MembershipWorksFlag

VALID_SEMVER_PATTERN = re.compile(
    r"(?P<semver>\d+\.\d+\.\d+) - (?P<approvaldate>\d{4}-\d{2}-\d{2})"
)


class CmsRedRiverVeteransScholarship(models.Model):
    serial = models.AutoField(primary_key=True)
    program_name = models.CharField(db_column="Program Name", max_length=255)
    member_name = models.CharField(
        db_column="Member Name", max_length=255, blank=True, null=True
    )
    discount_percent = models.DecimalField(
        db_column="Discount Percent",
        max_digits=16,
        decimal_places=0,
        blank=True,
        null=True,
    )
    discount_code = models.CharField(
        db_column="Discount Code", max_length=255, blank=True, null=True
    )
    membership_code = models.CharField(
        db_column="Membership Code", max_length=255, blank=True, null=True
    )
    start_date = models.DateField(db_column="Start Date", blank=True, null=True)
    end_date = models.DateField(db_column="End Date", blank=True, null=True)
    program_amount = models.DecimalField(
        db_column="Program Amount",
        max_digits=16,
        decimal_places=0,
        blank=True,
        null=True,
    )
    program_status = models.CharField(
        db_column="Program Status", max_length=16, blank=True, null=True
    )

    def __str__(self):
        return f"{self.program_name} {self.member_name}"

    class Meta:
        db_table = "CMS Red River Veterans Scholarship"


class Department(models.Model):
    name = models.CharField(
        max_length=64,
        validators=[RegexValidator("^[-_ A-Za-z0-9]*$")],
        help_text="This will also be used to generate the mailing list name",
    )
    parent = models.ForeignKey(
        "self", on_delete=models.PROTECT, related_name="children", blank=True, null=True
    )
    has_mailing_list = models.BooleanField(default=False)
    list_moderator_flag = models.ForeignKey(
        MembershipWorksFlag,
        on_delete=models.PROTECT,
        blank=True,
        null=True,
        db_constraint=False,
    )
    list_reply_to_address = models.EmailField(max_length=254, blank=True)

    def __str__(self):
        return self.name

    @property
    def list_name(self):
        return self.name.replace(" ", "_") + "-info"


class CertificationDefinition(models.Model):
    certification_identifier = models.AutoField(
        db_column="Certification Identifier", primary_key=True
    )
    certification_name = models.CharField(
        db_column="Certification Name", max_length=255, blank=True, null=True
    )
    department = models.ForeignKey(Department, models.PROTECT)

    def __str__(self):
        return f"{self.certification_name} <{self.department}>"

    class Meta:
        db_table = "Certification Definitions"
        ordering = ("certification_name", "department")

    def latest_version(self) -> "CertificationVersion":
        all_versions = CertificationVersion.objects.filter(definition=self)

        return max(all_versions, key=lambda version: version.semantic_version())


class CertificationVersion(models.Model):
    definition = models.ForeignKey(
        CertificationDefinition, on_delete=models.PROTECT, db_column="Certification"
    )
    version = models.CharField(
        db_column="Version", max_length=255, blank=True, null=True
    )

    def __str__(self):
        return f"{self.definition} [{self.version}]"

    class Meta:
        constraints = [
            models.UniqueConstraint(
                fields=["definition", "version"], name="unique_certification_version"
            )
        ]

    def semantic_version(self) -> semver.VersionInfo:
        if self.version is None:
            return "0.0.0-none"
        elif self.version == "MembershipWorks Label":
            return semver.parse_version_info("0.0.1-mw-label")
        elif match := VALID_SEMVER_PATTERN.match(self.version):
            return semver.parse_version_info(
                f'{match["semver"]}+{match["approvaldate"]}'
            )
        else:
            return semver.parse_version_info(
                "0.0.1-" + re.sub(r"[^.a-zA-Z0-9]", "-", self.version)
            )

    def is_latest(self) -> bool:
        return self.definition.latest_version() == self

    is_latest.boolean = True

    def is_current(self) -> bool:
        """Returns true if this version compatible with the latest version"""
        # TODO: should do a more correct comparison than just major version
        return (
            self.definition.latest_version().semantic_version().major
            == self.semantic_version().major
        )

    is_current.boolean = True


class Certification(models.Model):
    number = models.AutoField(db_column="Number", primary_key=True)
    certification_version = models.ForeignKey(
        CertificationVersion, on_delete=models.PROTECT
    )
    name = models.CharField(db_column="Name", max_length=255)
    member = models.ForeignKey(
        Member,
        on_delete=models.PROTECT,
        to_field="uid",
        db_column="uid",
        blank=True,
        null=True,
        db_constraint=False,
    )
    certified_by = models.CharField(
        db_column="Certified_By", max_length=255, blank=True, null=True
    )
    date = models.DateField(db_column="Date", blank=True, null=True)
    shop_lead_notified = models.DateTimeField(
        db_column="Shop Lead Notified", blank=True, null=True
    )
    notes = models.CharField(db_column="Notes", max_length=255, blank=True, null=True)

    def __str__(self):
        return f"{self.name} - {self.certification_version}"

    class Meta:
        db_table = "Certifications"
        permissions = [
            (
                "receive_certification_emails",
                "Receives notifications of all new certifications",
            ),
        ]


class InstructorOrVendor(models.Model):
    serial = models.AutoField(primary_key=True)
    name = models.CharField(db_column="Name", max_length=255)
    instructor_agreement_date = models.DateField(
        db_column="Instructor Agreement Date", blank=True, null=True
    )
    w9_date = models.DateField(db_column="W9 date", blank=True, null=True)
    phone = models.CharField(max_length=255, blank=True, null=True)
    email_address = models.CharField(
        db_column="email address", max_length=255, blank=True, null=True
    )

    def __str__(self):
        return f"{self.name}"

    class Meta:
        db_table = "Instructors and Vendors"


class SpecialProgram(models.Model):
    program_name = models.CharField(
        db_column="Program Name", primary_key=True, max_length=255
    )
    discount_percent = models.DecimalField(
        db_column="Discount Percent",
        max_digits=16,
        decimal_places=0,
        blank=True,
        null=True,
    )
    discount_code = models.CharField(
        db_column="Discount Code", max_length=255, blank=True, null=True
    )
    membership_code = models.CharField(
        db_column="Membership Code", max_length=255, blank=True, null=True
    )
    start_date = models.DateField(db_column="Start Date", blank=True, null=True)
    end_date = models.DateField(db_column="End Date", blank=True, null=True)
    program_amount = models.DecimalField(
        db_column="Program Amount",
        max_digits=16,
        decimal_places=0,
        blank=True,
        null=True,
    )
    program_status = models.CharField(
        db_column="Program Status", max_length=16, blank=True, null=True
    )

    def __str__(self):
        return self.program_name

    class Meta:
        db_table = "Special_Programs"


class Waiver(models.Model):
    number = models.AutoField(db_column="Number", primary_key=True)
    name = models.CharField(db_column="Name", max_length=255)
    date = models.DateField(db_column="Date")
    emergency_contact_name = models.CharField(
        db_column="Emergency Contact Name", max_length=255, blank=True, null=True
    )
    emergency_contact_number = models.CharField(
        db_column="Emergency Contact Number", max_length=25, blank=True, null=True
    )
    waiver_version = models.CharField(db_column="Waiver version", max_length=64)
    guardian_name = models.CharField(
        db_column="Guardian Name", max_length=255, blank=True, null=True
    )
    guardian_relation = models.CharField(
        db_column="Guardian Relation", max_length=255, blank=True, null=True
    )
    guardian_date = models.DateField(db_column="Guardian Date", blank=True, null=True)

    def __str__(self):
        return f"{self.name} {self.date}"

    class Meta:
        db_table = "Waivers"