"""Submission + Filament models -- the data layer for plan.md §5.

The state machine lives in `Submission.Status`; transitions and side-effects
are documented in plan.md §7.
"""

from __future__ import annotations

import uuid

from django.conf import settings
from django.core.validators import FileExtensionValidator
from django.db import models
from django.urls import reverse


def _validate_stl_size(uploaded_file) -> None:
    """Hard 4 MB cap on uploaded `.stl` files -- mirrors plan.md §5."""
    from django.core.exceptions import ValidationError

    max_bytes = 4 * 1024 * 1024
    if uploaded_file.size > max_bytes:
        raise ValidationError(
            f"STL file is {uploaded_file.size // 1024} KB; max is "
            f"{max_bytes // 1024} KB."
        )


class Filament(models.Model):
    """Operator-curated filament inventory (plan.md §5).

    The submit form's "Filament" dropdown is populated from rows with
    `is_available = True`. Filaments are protected from deletion while
    referenced by an in-flight `Submission`; the correct workflow is to
    flip `is_available = False`.
    """

    class Material(models.TextChoices):
        PLA = "PLA", "PLA"
        PLA_PLUS = "PLA+", "PLA+"
        PETG = "PETG", "PETG"
        ABS = "ABS", "ABS"
        TPU = "TPU", "TPU"
        ASA = "ASA", "ASA"
        NYLON = "Nylon", "Nylon"
        OTHER = "Other", "Other"

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    material = models.CharField(max_length=16, choices=Material.choices)
    color_name = models.CharField(max_length=64)
    swatch_hex = models.CharField(max_length=7, blank=True, help_text="#RRGGBB")
    is_available = models.BooleanField(default=True)
    notes = models.CharField(max_length=200, blank=True)
    sort_order = models.IntegerField(default=0)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ("sort_order", "color_name")
        indexes = [
            models.Index(fields=["is_available"]),
            models.Index(fields=["sort_order", "color_name"]),
        ]

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

    @property
    def display_label(self) -> str:
        return f"{self.color_name} {self.material}"


class Submission(models.Model):
    """A 3D-print job. State machine documented in plan.md §7."""

    class Status(models.TextChoices):
        IDENTIFYING = "identifying", "Identifying"
        PROCESSING = "processing", "Processing"
        VERIFYING = "verifying", "Verifying"
        QUEUED = "queued", "Queued"
        PRINTING = "printing", "Printing"
        COMPLETED = "completed", "Completed"
        REJECTED = "rejected", "Rejected"
        FAILED = "failed", "Failed"

    class SourceType(models.TextChoices):
        UPLOAD = "upload", "Raw .stl upload"
        PRINTABLES = "printables", "Printables.com"
        MAKERWORLD = "makerworld", "MakerWorld"
        THINGIVERSE = "thingiverse", "Thingiverse"

    DASHBOARD_VISIBLE_STATUSES = (
        Status.VERIFYING,
        Status.QUEUED,
        Status.PRINTING,
        Status.COMPLETED,
    )
    TERMINAL_STATUSES = (Status.COMPLETED, Status.FAILED, Status.REJECTED)

    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
    slug = models.CharField(max_length=64, unique=True, db_index=True)

    submitted_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="submissions",
    )
    guest_email = models.EmailField(null=True, blank=True)
    email_confirmed = models.BooleanField(default=False)
    confirmation_token = models.CharField(
        max_length=64, null=True, blank=True, db_index=True
    )
    confirmation_sent_at = models.DateTimeField(null=True, blank=True)

    source_type = models.CharField(
        max_length=16,
        choices=SourceType.choices,
        default=SourceType.UPLOAD,
    )
    stl_file = models.FileField(
        upload_to="stl/",
        null=True,
        blank=True,
        validators=[
            FileExtensionValidator(allowed_extensions=["stl"]),
            _validate_stl_size,
        ],
    )
    source_url = models.URLField(null=True, blank=True)
    requested_filament = models.ForeignKey(
        Filament,
        on_delete=models.PROTECT,
        null=True,
        blank=True,
        related_name="submissions",
    )

    notes_for_op = models.TextField(blank=True)

    status = models.CharField(
        max_length=16,
        choices=Status.choices,
        default=Status.IDENTIFYING,
        db_index=True,
    )
    operator_notes = models.TextField(blank=True)
    closed_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="closed_submissions",
    )
    closed_at = models.DateTimeField(null=True, blank=True)

    created_at = models.DateTimeField(auto_now_add=True, db_index=True)
    updated_at = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ("-created_at",)
        constraints = [
            models.CheckConstraint(
                name="submission_has_contact_identity",
                condition=(
                    models.Q(submitted_by__isnull=False)
                    | models.Q(guest_email__isnull=False)
                ),
            ),
        ]

    def __str__(self) -> str:
        return f"{self.slug} ({self.get_status_display()})"

    def get_absolute_url(self) -> str:
        # The dashboard detail route is not wired yet; fall back to the
        # dashboard index so post-submit redirects always land somewhere real.
        return reverse("dashboard:index")

    # --- presentation helpers (consumed by dashboard templates) -------------

    SOURCE_LABEL = {
        SourceType.UPLOAD: ".stl upload",
        SourceType.PRINTABLES: "printables.com",
        SourceType.MAKERWORLD: "makerworld.com",
        SourceType.THINGIVERSE: "thingiverse.com",
    }

    # Tailwind class string per status, kept here (not in the template) so the
    # palette is defined in one place and Tailwind's @source-scanner picks the
    # literal class strings up from apps/.
    STATUS_BADGE_CLASS = {
        Status.IDENTIFYING: "bg-yellow-100 text-yellow-800",
        Status.PROCESSING: "bg-slate-100 text-slate-700",
        Status.VERIFYING: "bg-violet-100 text-violet-800",
        Status.QUEUED: "bg-blue-100 text-blue-800",
        Status.PRINTING: "bg-orange-100 text-orange-800",
        Status.COMPLETED: "bg-emerald-100 text-emerald-800",
        Status.REJECTED: "bg-red-100 text-red-800",
        Status.FAILED: "bg-red-100 text-red-800",
    }

    @property
    def source_label(self) -> str:
        return self.SOURCE_LABEL.get(self.source_type, self.source_type)

    @property
    def status_badge_class(self) -> str:
        return self.STATUS_BADGE_CLASS.get(self.status, "bg-slate-100 text-slate-700")