from __future__ import annotations

from django.db import models


class TimestampedModel(models.Model):
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        abstract = True


class GlobalConfig(TimestampedModel):
    name = models.CharField(max_length=64, default="default", unique=True)
    backup_root = models.CharField(max_length=512)
    default_ssh_credential = models.ForeignKey(
        "SshCredential",
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="global_configs",
    )
    ssh_user = models.CharField(max_length=64, default="root")
    ssh_port = models.PositiveIntegerField(default=22)
    ssh_options = models.JSONField(default=list, blank=True)
    rsync_binary = models.CharField(max_length=128, default="rsync")
    rsync_args = models.JSONField(default=list, blank=True)
    rsync_extra_args = models.JSONField(default=list, blank=True)
    rsync_timeout_seconds = models.PositiveIntegerField(default=0)
    rsync_bwlimit_kbps = models.PositiveIntegerField(default=0)
    default_source_root = models.CharField(max_length=512, default="/")
    default_destination_subdir = models.CharField(max_length=512, default="", blank=True)
    excludes_default = models.JSONField(default=list, blank=True)
    retention_daily = models.PositiveIntegerField(default=14)
    retention_weekly = models.PositiveIntegerField(default=8)
    retention_monthly = models.PositiveIntegerField(default=12)
    retention_yearly = models.PositiveIntegerField(default=0)

    class Meta:
        verbose_name = "global config"
        verbose_name_plural = "global configs"

    def __str__(self) -> str:
        return self.name


class HostConfig(TimestampedModel):
    host = models.CharField(max_length=255, unique=True)
    address = models.CharField(max_length=255)
    enabled = models.BooleanField(default=True)
    ssh_credential = models.ForeignKey(
        "SshCredential",
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="hosts",
    )
    ssh_user = models.CharField(max_length=64, blank=True)
    ssh_port = models.PositiveIntegerField(null=True, blank=True)
    source_root = models.CharField(max_length=512, blank=True)
    includes = models.JSONField(default=list, blank=True)
    excludes_add = models.JSONField(default=list, blank=True)
    excludes_replace = models.JSONField(null=True, blank=True)
    rsync_extra_args = models.JSONField(default=list, blank=True)
    retention_daily = models.PositiveIntegerField(default=14)
    retention_weekly = models.PositiveIntegerField(default=8)
    retention_monthly = models.PositiveIntegerField(default=12)
    retention_yearly = models.PositiveIntegerField(default=0)
    config = models.JSONField(default=dict, blank=True)

    class Meta:
        ordering = ["host"]

    def __str__(self) -> str:
        return self.host


class SshCredential(TimestampedModel):
    name = models.CharField(max_length=128, unique=True)
    private_key = models.TextField(blank=True, default="")
    public_key = models.TextField(blank=True)
    key_path = models.CharField(max_length=1024, blank=True)
    key_type = models.CharField(max_length=32, default="ed25519")
    fingerprint = models.CharField(max_length=255, blank=True)
    generated = models.BooleanField(default=False)
    known_hosts = models.TextField(blank=True)
    notes = models.TextField(blank=True)

    class Meta:
        ordering = ["name"]

    def __str__(self) -> str:
        return self.name


class BackupRun(models.Model):
    class RunType(models.TextChoices):
        SCHEDULED = "scheduled", "Scheduled"
        MANUAL = "manual", "Manual"

    class Status(models.TextChoices):
        QUEUED = "queued", "Queued"
        RUNNING = "running", "Running"
        SUCCESS = "success", "Success"
        WARNING = "warning", "Warning"
        FAILED = "failed", "Failed"
        CANCELLED = "cancelled", "Cancelled"

    host = models.ForeignKey(HostConfig, on_delete=models.PROTECT, related_name="runs")
    run_type = models.CharField(max_length=16, choices=RunType.choices, default=RunType.SCHEDULED)
    status = models.CharField(max_length=16, choices=Status.choices, default=Status.QUEUED)
    started_at = models.DateTimeField(null=True, blank=True)
    ended_at = models.DateTimeField(null=True, blank=True)
    snapshot_path = models.CharField(max_length=1024, blank=True)
    snapshot = models.ForeignKey(
        "SnapshotRecord",
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="backup_runs",
    )
    base_path = models.CharField(max_length=1024, blank=True)
    rsync_exit_code = models.IntegerField(null=True, blank=True)
    result = models.JSONField(default=dict, blank=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ["-created_at"]

    def __str__(self) -> str:
        return f"{self.host} {self.run_type} {self.status}"


class SnapshotRecord(models.Model):
    class Kind(models.TextChoices):
        SCHEDULED = "scheduled", "Scheduled"
        MANUAL = "manual", "Manual"
        INCOMPLETE = "incomplete", "Incomplete"

    host = models.ForeignKey(HostConfig, on_delete=models.CASCADE, related_name="snapshots")
    kind = models.CharField(max_length=16, choices=Kind.choices)
    dirname = models.CharField(max_length=255)
    path = models.CharField(max_length=1024)
    base = models.ForeignKey(
        "self",
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="derived_snapshots",
    )
    base_kind = models.CharField(max_length=16, blank=True)
    base_dirname = models.CharField(max_length=255, blank=True)
    base_path = models.CharField(max_length=1024, blank=True)
    base_snapshot_id = models.CharField(max_length=64, blank=True)
    status = models.CharField(max_length=32, blank=True)
    started_at = models.DateTimeField(null=True, blank=True)
    ended_at = models.DateTimeField(null=True, blank=True)
    metadata = models.JSONField(default=dict, blank=True)
    discovered_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        constraints = [
            models.UniqueConstraint(fields=["host", "kind", "dirname"], name="unique_snapshot_per_host_kind"),
        ]
        ordering = ["host__host", "-started_at", "dirname"]

    def __str__(self) -> str:
        return f"{self.host}/{self.kind}/{self.dirname}"


class ScheduleConfig(TimestampedModel):
    host = models.OneToOneField(HostConfig, on_delete=models.CASCADE, related_name="schedule")
    cron_expr = models.CharField(max_length=128)
    enabled = models.BooleanField(default=True)
    prune = models.BooleanField(default=False)
    prune_max_delete = models.PositiveIntegerField(default=10)
    prune_protect_bases = models.BooleanField(default=False)
    last_due_key = models.CharField(max_length=32, blank=True)
    last_started_at = models.DateTimeField(null=True, blank=True)
    last_finished_at = models.DateTimeField(null=True, blank=True)
    last_status = models.CharField(max_length=16, blank=True)

    class Meta:
        ordering = ["host__host"]

    def __str__(self) -> str:
        return f"{self.host} {self.cron_expr}"