from django.conf import settings
from django.db import models
from django.db.models import Q

from infrasynth.tenancy.mixins import GlobalOrTenantModel, TenantOwnedModel


class StoredFile(TenantOwnedModel):
    storage_backend = models.CharField(max_length=50)
    storage_key = models.CharField(max_length=500)
    original_filename = models.CharField(max_length=500)
    mime_type = models.CharField(max_length=255)
    size_bytes = models.BigIntegerField()
    checksum_sha256 = models.CharField(max_length=64)
    is_public = models.BooleanField(default=False)
    category = models.ForeignKey(
        "FileCategory",
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="+",
    )
    metadata = models.JSONField(default=dict)
    uploaded_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="+",
    )
    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        db_table = "files_stored_file"
        indexes = [models.Index(fields=["tenant_id", "created_at"])]


class FileCategory(TenantOwnedModel):
    slug = models.SlugField(max_length=100)
    name = models.CharField(max_length=200)
    description = models.TextField(blank=True)
    storage_path = models.CharField(max_length=500)
    allowed_extensions = models.TextField(blank=True)
    max_size_bytes = models.BigIntegerField(null=True, blank=True)
    is_active = models.BooleanField(default=True)
    storage_backend_override = models.CharField(max_length=50, blank=True)

    class Meta:
        db_table = "files_category"
        constraints = [
            models.UniqueConstraint(fields=["tenant", "slug"], name="uniq_file_category_slug_per_tenant"),
        ]


class ProcessingPipeline(GlobalOrTenantModel):
    name = models.CharField(max_length=200)
    slug = models.SlugField(max_length=100)
    steps = models.JSONField()
    is_active = models.BooleanField(default=True)

    class Meta:
        db_table = "files_pipeline"
        constraints = [
            models.UniqueConstraint(fields=["tenant", "slug"], name="uniq_pipeline_slug_per_tenant"),
            models.UniqueConstraint(
                fields=["slug"],
                condition=Q(tenant__isnull=True),
                name="uniq_global_pipeline_slug",
            ),
        ]


class PipelineExecution(TenantOwnedModel):
    class Status(models.TextChoices):
        PENDING = "pending", "Pending"
        RUNNING = "running", "Running"
        COMPLETED = "completed", "Completed"
        FAILED = "failed", "Failed"

    file = models.ForeignKey(StoredFile, on_delete=models.CASCADE, related_name="pipeline_executions")
    pipeline = models.ForeignKey(
        ProcessingPipeline,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="+",
    )
    status = models.CharField(max_length=20, choices=Status.choices, default=Status.PENDING)
    started_at = models.DateTimeField(null=True, blank=True)
    completed_at = models.DateTimeField(null=True, blank=True)
    output_file = models.ForeignKey(
        StoredFile,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name="+",
    )
    error = models.TextField(blank=True)

    class Meta:
        db_table = "files_pipeline_execution"
        indexes = [models.Index(fields=["tenant_id", "status"])]