import uuid
from datetime import timedelta

from django.conf import settings
from django.db import models
from django.utils import timezone


def default_ticket_draft_expiry():
    return timezone.now() + timedelta(hours=24)


class TicketStatus(models.TextChoices):
    PENDING_INFO = "pending_info", "Pending info"
    PENDING = "pending", "Pending"
    IN_PROGRESS = "in_progress", "In progress"
    PENDING_CONFIRM = "pending_confirm", "Pending confirm"
    RESOLVED = "resolved", "Resolved"
    CLOSED = "closed", "Closed"


class TicketPriority(models.TextChoices):
    LOW = "low", "Low"
    MEDIUM = "medium", "Medium"
    HIGH = "high", "High"
    URGENT = "urgent", "Urgent"


class TicketCategory(models.Model):
    parent = models.ForeignKey("self", null=True, blank=True, on_delete=models.SET_NULL)
    name = models.CharField(max_length=120)
    code = models.CharField(max_length=80, unique=True)
    description = models.TextField(blank=True)
    enabled = models.BooleanField(default=True)
    sort_order = models.PositiveIntegerField(default=0)

    class Meta:
        ordering = ["sort_order", "name"]

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


class Ticket(models.Model):
    ticket_no = models.CharField(max_length=32, unique=True)
    title = models.CharField(max_length=200)
    description = models.TextField()
    category = models.ForeignKey(TicketCategory, null=True, blank=True, on_delete=models.SET_NULL)
    status = models.CharField(
        max_length=32,
        choices=TicketStatus.choices,
        default=TicketStatus.PENDING,
    )
    priority = models.CharField(
        max_length=20,
        choices=TicketPriority.choices,
        default=TicketPriority.MEDIUM,
    )
    problem_performance = models.TextField(blank=True)
    problem_object = models.CharField(max_length=160, blank=True)
    submitter_name = models.CharField(max_length=80, blank=True)
    submitter_org = models.CharField(max_length=160, blank=True)
    ai_solution = models.TextField(blank=True)
    resolution_summary = models.TextField(blank=True)
    is_resolved = models.BooleanField(default=False)
    replied_to_customer = models.BooleanField(default=False)
    impact_scope = models.CharField(max_length=80, blank=True)
    environment = models.CharField(max_length=80, blank=True)
    related_system = models.CharField(max_length=120, blank=True)
    requester = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="requested_tickets",
    )
    assignee = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="assigned_tickets",
    )
    created_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="created_tickets",
    )
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    resolved_at = models.DateTimeField(null=True, blank=True)
    closed_at = models.DateTimeField(null=True, blank=True)

    class Meta:
        ordering = ["-created_at"]
        indexes = [
            models.Index(fields=["ticket_no"]),
            models.Index(fields=["status", "priority"]),
            models.Index(fields=["created_at"]),
        ]

    def __str__(self) -> str:
        return f"{self.ticket_no} {self.title}"


class TicketComment(models.Model):
    ticket = models.ForeignKey(Ticket, on_delete=models.CASCADE, related_name="comments")
    content = models.TextField()
    comment_type = models.CharField(max_length=40, default="user")
    visibility = models.CharField(max_length=40, default="internal")
    created_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
    )
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ["created_at"]


class TicketAttachment(models.Model):
    ticket = models.ForeignKey(Ticket, on_delete=models.CASCADE, related_name="attachments")
    file_name = models.CharField(max_length=255)
    file_type = models.CharField(max_length=80, blank=True)
    mime_type = models.CharField(max_length=120, blank=True)
    file_size = models.PositiveBigIntegerField(default=0)
    storage_path = models.CharField(max_length=500)
    ocr_text = models.TextField(blank=True)
    parsed_text = models.TextField(blank=True)
    created_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
    )
    created_at = models.DateTimeField(auto_now_add=True)


class TicketDraft(models.Model):
    public_id = models.UUIDField(default=uuid.uuid4, unique=True, editable=False)
    created_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
        related_name="ticket_drafts",
    )
    status = models.CharField(max_length=24, default="editing")
    revision = models.PositiveIntegerField(default=1)
    source_text = models.TextField(blank=True)
    current_fields = models.JSONField(default=dict)
    last_ai_fields = models.JSONField(default=dict)
    missing_fields = models.JSONField(default=list)
    questions = models.JSONField(default=list)
    guided_rounds = models.PositiveSmallIntegerField(default=0)
    latest_agent_run = models.ForeignKey(
        "agents.AgentRun",
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="ticket_drafts",
    )
    latest_artifact = models.ForeignKey(
        "agents.AgentArtifact",
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="ticket_drafts",
    )
    confirmed_ticket = models.OneToOneField(
        Ticket,
        null=True,
        blank=True,
        on_delete=models.PROTECT,
        related_name="source_draft",
    )
    decision = models.CharField(max_length=24, blank=True)
    error_code = models.CharField(max_length=80, blank=True)
    error_message = models.TextField(blank=True)
    expires_at = models.DateTimeField(default=default_ticket_draft_expiry)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    confirmed_at = models.DateTimeField(null=True, blank=True)

    class Meta:
        ordering = ["-updated_at"]
        indexes = [
            models.Index(fields=["created_by", "status", "updated_at"]),
            models.Index(fields=["status", "expires_at"]),
        ]


class TicketDraftMessage(models.Model):
    draft = models.ForeignKey(TicketDraft, on_delete=models.CASCADE, related_name="messages")
    role = models.CharField(max_length=24)
    content = models.TextField()
    round_number = models.PositiveSmallIntegerField(default=0)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ["created_at"]


class TicketDraftImage(models.Model):
    public_id = models.UUIDField(default=uuid.uuid4, unique=True, editable=False)
    draft = models.ForeignKey(TicketDraft, on_delete=models.CASCADE, related_name="images")
    file_name = models.CharField(max_length=255)
    mime_type = models.CharField(max_length=120)
    file_size = models.PositiveBigIntegerField()
    sha256 = models.CharField(max_length=64)
    storage_path = models.CharField(max_length=500)
    status = models.CharField(max_length=24, default="temporary")
    confirmed_attachment = models.OneToOneField(
        TicketAttachment,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
        related_name="source_draft_image",
    )
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ["created_at"]


class TicketEvent(models.Model):
    ticket = models.ForeignKey(Ticket, on_delete=models.CASCADE, related_name="events")
    event_type = models.CharField(max_length=80)
    from_value = models.JSONField(default=dict, blank=True)
    to_value = models.JSONField(default=dict, blank=True)
    operator = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        blank=True,
        on_delete=models.SET_NULL,
    )
    remark = models.TextField(blank=True)
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ["created_at"]