"""Database-driven workflow definitions.

The engine knows only generic concepts (steps, transitions, conditions,
versions). Business processes (washing, drying, sorting, ...) are data, never
code. Do NOT add hard-coded step names or branching here.
"""
from django.db import models

from apps.core.models import TimeStampedModel, UUIDModel


class Workflow(UUIDModel, TimeStampedModel):
    class Status(models.TextChoices):
        DRAFT = "draft", "Draft"
        ACTIVE = "active", "Active"
        INACTIVE = "inactive", "Inactive"
        ARCHIVED = "archived", "Archived"

    name = models.CharField(max_length=200)
    slug = models.SlugField(max_length=200, unique=True)
    description = models.TextField(blank=True)
    status = models.CharField(max_length=16, choices=Status.choices, default=Status.DRAFT)
    active_version = models.OneToOneField(
        "WorkflowVersion", null=True, blank=True, on_delete=models.SET_NULL, related_name="+"
    )

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


class WorkflowVersion(UUIDModel, TimeStampedModel):
    class Status(models.TextChoices):
        DRAFT = "draft", "Draft"
        ACTIVE = "active", "Active"
        INACTIVE = "inactive", "Inactive"
        ARCHIVED = "archived", "Archived"

    workflow = models.ForeignKey(Workflow, on_delete=models.CASCADE, related_name="versions")
    version = models.PositiveIntegerField()
    status = models.CharField(max_length=16, choices=Status.choices, default=Status.DRAFT)
    published_at = models.DateTimeField(null=True, blank=True)

    class Meta:
        ordering = ["-version"]
        constraints = [
            models.UniqueConstraint(fields=["workflow", "version"], name="uniq_workflow_version")
        ]

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


class WorkflowStep(UUIDModel):
    class StepType(models.TextChoices):
        TASK = "task", "Task"
        DECISION = "decision", "Decision"
        INPUT = "input", "Input"
        OUTPUT = "output", "Output"
        INTEGRATION = "integration", "Integration"

    version = models.ForeignKey(WorkflowVersion, on_delete=models.CASCADE, related_name="steps")
    key = models.SlugField(max_length=100)
    name = models.CharField(max_length=200)
    description = models.TextField(blank=True)
    order = models.PositiveIntegerField(default=0)
    step_type = models.CharField(max_length=16, choices=StepType.choices, default=StepType.TASK)
    required = models.BooleanField(default=False)
    enabled = models.BooleanField(default=True)
    estimated_duration_minutes = models.PositiveIntegerField(default=0)
    is_start = models.BooleanField(default=False)
    is_terminal = models.BooleanField(default=False)
    requires_customer_confirmation = models.BooleanField(default=False)
    requires_payment = models.BooleanField(default=False)
    triggers_invoice = models.BooleanField(default=False)
    triggers_odoo_sync = models.BooleanField(default=False)
    customer_visible = models.BooleanField(default=True)
    operator_visible = models.BooleanField(default=True)
    live_monitoring_enabled = models.BooleanField(default=False)
    input_schema = models.JSONField(default=dict, blank=True)
    output_schema = models.JSONField(default=dict, blank=True)
    # Optional condition (dict) that gates whether this step is available.
    availability_condition = models.JSONField(default=dict, blank=True)
    # Canvas position for the visual workflow designer.
    position_x = models.FloatField(default=0)
    position_y = models.FloatField(default=0)

    class Meta:
        ordering = ["order"]
        constraints = [
            models.UniqueConstraint(fields=["version", "key"], name="uniq_step_key")
        ]

    def __str__(self) -> str:
        return f"{self.key} ({self.version})"


class WorkflowTransition(UUIDModel):
    version = models.ForeignKey(WorkflowVersion, on_delete=models.CASCADE, related_name="transitions")
    from_step = models.ForeignKey(WorkflowStep, on_delete=models.CASCADE, related_name="outgoing")
    to_step = models.ForeignKey(WorkflowStep, on_delete=models.CASCADE, related_name="incoming")
    # List of condition dicts, e.g. [{"type": "step_completed", "step": "drying"}]
    conditions = models.JSONField(default=list, blank=True)
    required_roles = models.ManyToManyField("rbac.Role", blank=True)

    class Meta:
        constraints = [
            models.UniqueConstraint(fields=["version", "from_step", "to_step"], name="uniq_transition")
        ]

    def __str__(self) -> str:
        return f"{self.from_step.key} -> {self.to_step.key}"