feat: add governed postbox delivery and report hardening

src/govoplan_campaign/backend/campaign/models.py

@@ -23,6 +23,8 @@ class FieldType(StrEnum):
     DOUBLE = "double"
     DATE = "date"
     PASSWORD = "password"  # noqa: S105  # nosec B105 - field type vocabulary.
+    ORGANIZATION_UNIT = "organization_unit"
+    ORGANIZATION_FUNCTION = "organization_function"
 
 
 class RecipientType(StrEnum):
@@ -92,6 +94,104 @@ class SendStatus(StrEnum):
     SKIPPED = "skipped"
 
 
+class DeliveryChannelPolicy(StrEnum):
+    MAIL = "mail"
+    POSTBOX = "postbox"
+    MAIL_AND_POSTBOX = "mail_and_postbox"
+    MAIL_THEN_POSTBOX = "mail_then_postbox"
+    POSTBOX_THEN_MAIL = "postbox_then_mail"
+
+    @property
+    def uses_mail(self) -> bool:
+        return self in {
+            DeliveryChannelPolicy.MAIL,
+            DeliveryChannelPolicy.MAIL_AND_POSTBOX,
+            DeliveryChannelPolicy.MAIL_THEN_POSTBOX,
+            DeliveryChannelPolicy.POSTBOX_THEN_MAIL,
+        }
+
+    @property
+    def uses_postbox(self) -> bool:
+        return self != DeliveryChannelPolicy.MAIL
+
+
+class PostboxTargetMode(StrEnum):
+    DIRECT = "direct"
+    DERIVED = "derived"
+
+
+class PostboxTargetMatch(StrEnum):
+    ID = "id"
+    SLUG = "slug"
+
+
+class PostboxTargetConfig(StrictModel):
+    id: str = Field(min_length=1, max_length=120)
+    mode: PostboxTargetMode = PostboxTargetMode.DIRECT
+    label: str | None = Field(default=None, max_length=500)
+
+    postbox_id: str | None = Field(default=None, max_length=36)
+    address_key: str | None = Field(default=None, max_length=500)
+
+    template_id: str | None = Field(default=None, max_length=36)
+    organization_unit_id: str | None = Field(default=None, max_length=36)
+    organization_unit_field: str | None = Field(default=None, max_length=255)
+    organization_unit_match: PostboxTargetMatch = PostboxTargetMatch.ID
+    function_id: str | None = Field(default=None, max_length=36)
+    function_field: str | None = Field(default=None, max_length=255)
+    function_match: PostboxTargetMatch = PostboxTargetMatch.ID
+    context_key: str | None = Field(default=None, max_length=255)
+    context_field: str | None = Field(default=None, max_length=255)
+
+    @model_validator(mode="after")
+    def validate_target_shape(self) -> "PostboxTargetConfig":
+        direct_values = [self.postbox_id, self.address_key]
+        if self.mode == PostboxTargetMode.DIRECT:
+            if sum(bool(value) for value in direct_values) != 1:
+                raise ValueError(
+                    "A direct Postbox target requires exactly one postbox_id "
+                    "or address_key."
+                )
+            if any(
+                (
+                    self.template_id,
+                    self.organization_unit_id,
+                    self.organization_unit_field,
+                    self.function_id,
+                    self.function_field,
+                    self.context_key,
+                    self.context_field,
+                )
+            ):
+                raise ValueError(
+                    "A direct Postbox target cannot contain derived target fields."
+                )
+            return self
+
+        if any(direct_values):
+            raise ValueError(
+                "A derived Postbox target cannot contain postbox_id or address_key."
+            )
+        if not self.template_id:
+            raise ValueError("A derived Postbox target requires template_id.")
+        if bool(self.organization_unit_id) == bool(self.organization_unit_field):
+            raise ValueError(
+                "A derived Postbox target requires exactly one fixed or "
+                "field-derived organization unit."
+            )
+        if bool(self.function_id) == bool(self.function_field):
+            raise ValueError(
+                "A derived Postbox target requires exactly one fixed or "
+                "field-derived function."
+            )
+        if self.context_key and self.context_field:
+            raise ValueError(
+                "A derived Postbox target may use a fixed context or a context "
+                "field, not both."
+            )
+        return self
+
+
 class CampaignMeta(StrictModel):
     id: str
     name: str
@@ -450,6 +550,13 @@ class EntryConfig(StrictModel):
     disposition_notification_to: list[RecipientConfig] = Field(default_factory=list)
     merge_disposition_notification_to: bool = True
 
+    channel_policy: DeliveryChannelPolicy | None = None
+    postbox_targets: list[PostboxTargetConfig] = Field(
+        default_factory=list,
+        max_length=50,
+    )
+    merge_postbox_targets: bool = True
+
     attachments: list[AttachmentConfig] = Field(default_factory=list)
     combine_attachments: bool = True
 
@@ -563,7 +670,17 @@ class RetryConfig(StrictModel):
         return values
 
 
+class PostboxDeliveryConfig(StrictModel):
+    targets: list[PostboxTargetConfig] = Field(default_factory=list, max_length=50)
+    classification: str = Field(default="internal", min_length=1, max_length=50)
+    unresolved_target: Behavior = Behavior.BLOCK
+    vacant_target: Behavior = Behavior.WARN
+    duplicate_target: Behavior = Behavior.WARN
+
+
 class DeliveryConfig(StrictModel):
+    channel_policy: DeliveryChannelPolicy = DeliveryChannelPolicy.MAIL
+    postbox: PostboxDeliveryConfig = Field(default_factory=PostboxDeliveryConfig)
     rate_limit: RateLimitConfig = Field(default_factory=RateLimitConfig)
     imap_append_sent: ImapAppendSentConfig = Field(default_factory=ImapAppendSentConfig)
     retry: RetryConfig = Field(default_factory=RetryConfig)
@@ -606,3 +723,23 @@ class CampaignConfig(StrictModel):
         if path.is_absolute():
             return path
         return (campaign_file.parent / path).resolve()
+
+
+def effective_delivery_channel_policy(
+    config: CampaignConfig,
+    entry: EntryConfig,
+) -> DeliveryChannelPolicy:
+    return entry.channel_policy or config.delivery.channel_policy
+
+
+def effective_postbox_targets(
+    config: CampaignConfig,
+    entry: EntryConfig,
+) -> list[PostboxTargetConfig]:
+    global_targets = list(config.delivery.postbox.targets)
+    individual_targets = list(entry.postbox_targets)
+    if not individual_targets:
+        return global_targets
+    if entry.merge_postbox_targets:
+        return [*global_targets, *individual_targets]
+    return individual_targets