from __future__ import annotations
from django.db import models
from django.contrib.auth import get_user_model
from django.utils import timezone

# Remove eager evaluation to avoid accessing settings before configured
# User = get_user_model()

def get_user_model_cached():
    return get_user_model()

class RemoteHost(models.Model):
    AUTH_METHOD_CHOICES = [
        ('ssh_key', 'SSH Key'),
        ('agent', 'SSH Agent'),
        ('password', 'Password'),  # not stored; prompt in future
    ]
    name = models.CharField(max_length=100)
    hostname = models.CharField(max_length=255)
    port = models.PositiveIntegerField(default=22)
    username = models.CharField(max_length=100)
    auth_method = models.CharField(max_length=20, choices=AUTH_METHOD_CHOICES, default='ssh_key')
    key_path = models.CharField(max_length=500, blank=True)
    strict_host_key_checking = models.BooleanField(default=True)
    notes = models.TextField(blank=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ['name']

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

class CommandLog(models.Model):
    STATUS_CHOICES = [
        ('running', 'Running'),
        ('ok', 'Success'),
        ('failed', 'Failed'),
        ('canceled', 'Canceled'),
        ('error', 'Error'),
    ]
    RUN_TYPE_CHOICES = [
        ('single','Single'),
        ('batch','Batch'),
    ]
    host = models.ForeignKey(RemoteHost, on_delete=models.CASCADE, related_name='command_logs')
    created_by = models.ForeignKey('auth.User', null=True, blank=True, on_delete=models.SET_NULL)
    command = models.TextField()
    args_json = models.JSONField(null=True, blank=True)
    run_type = models.CharField(max_length=10, choices=RUN_TYPE_CHOICES, default='single')
    failed_step = models.IntegerField(null=True, blank=True)
    started_at = models.DateTimeField(default=timezone.now)
    finished_at = models.DateTimeField(null=True, blank=True)
    status = models.CharField(max_length=20, choices=STATUS_CHOICES, default='running')
    exit_code = models.IntegerField(null=True, blank=True)
    output_tail = models.TextField(blank=True)

    class Meta:
        ordering = ['-started_at']

    def mark_finished(self, status: str, exit_code: int | None, tail: str | None, failed_step: int | None = None):
        self.status = status
        self.exit_code = exit_code
        self.failed_step = failed_step
        self.finished_at = timezone.now()
        if tail is not None:
            self.output_tail = tail
        self.save(update_fields=['status', 'exit_code', 'failed_step', 'finished_at', 'output_tail'])

    def duration(self):  # pragma: no cover simple helper
        end = self.finished_at or timezone.now()
        return (end - self.started_at).total_seconds()

class BatchScript(models.Model):
    name = models.CharField(max_length=100, unique=True)
    description = models.CharField(max_length=255, blank=True)
    script = models.TextField(help_text="One command per line. Lines starting with # are ignored.")
    created_by = models.ForeignKey('auth.User', null=True, blank=True, on_delete=models.SET_NULL)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ['name']

    def __str__(self):  # pragma: no cover simple
        return self.name

    def clean(self):  # normalize script formatting
        if self.script:
            normalized = self.script.replace('\r\n', '\n').replace('\r', '\n')
            lines = [ln.rstrip() for ln in normalized.split('\n')]
            # remove trailing empty lines
            while lines and not lines[-1].strip():
                lines.pop()
            self.script = '\n'.join(lines).strip('\n')

    def step_lines(self):  # returns list of effective lines excluding comments/blank
        if not self.script:
            return []
        return [l for l in self.script.split('\n') if l.strip() and not l.strip().startswith('#')]

    def step_count(self):  # pragma: no cover trivial
        return len(self.step_lines())

class CommandTask(models.Model):
    name = models.CharField(max_length=100, unique=True, help_text="Key used internally")
    label = models.CharField(max_length=150)
    command = models.TextField()
    description = models.CharField(max_length=255, blank=True)
    created_by = models.ForeignKey('auth.User', null=True, blank=True, on_delete=models.SET_NULL)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ['name']

    def __str__(self):  # pragma: no cover
        return self.label or self.name