# METADATA
# title: Data source policy for ds:receipts
# description: |
#   Governs who may upload (write) and who may read receipts.
#   Receipts are PII. agent-travel uploads during the chat; downstream agents
#   may only read by content_hash and only within an active user session.
# authors:
#   - CTO Agent <cto@basicstack.de>
# related_resources:
#   - ref: docs/architecture/v1.1.md#user-content-47-belege-receipts--upload-hashbindung-lesezugriff-entlang-der-kette
#   - ref: schemas/ds/receipts/v1.0.0.json
package proofedmesh.data_sources.receipts

import rego.v1

default allow := false

allow if {
	input.data_source == "ds:receipts"
	input.user_sub != ""
	input.session_id != ""
	some rule in agent_scope_rules
	rule.agent_id == input.agent_id
	rule.operation == input.operation
	filters_ok(rule)
}

agent_scope_rules := [
	{
		"agent_id": "agent-travel",
		"operation": "write",
		"required_filters": set(),
		"allowed_filters": set(),
	},
	{
		"agent_id": "agent-sink-mapping",
		"operation": "read",
		"required_filters": {"content_hash"},
		"allowed_filters": {"content_hash"},
	},
	{
		"agent_id": "agent-sink-posting",
		"operation": "read",
		"required_filters": {"content_hash"},
		"allowed_filters": {"content_hash"},
	},
]

filters_ok(rule) if {
	rule.operation == "write"
}

filters_ok(rule) if {
	rule.operation == "read"
	provided := {k | some k; _ := input.filters[k]}
	count(provided - rule.allowed_filters) == 0
	count(rule.required_filters - provided) == 0
}

deny_reason contains msg if {
	input.data_source != "ds:receipts"
	msg := sprintf("wrong data_source: %s", [input.data_source])
}

deny_reason contains msg if {
	input.user_sub == ""
	msg := "missing user_sub (receipts always require an active user session)"
}

deny_reason contains msg if {
	not any_rule_matches
	msg := sprintf("no scope rule for agent=%s op=%s", [input.agent_id, input.operation])
}

any_rule_matches if {
	some rule in agent_scope_rules
	rule.agent_id == input.agent_id
	rule.operation == input.operation
}