import json

from scripts.dynamic_dispatch_optimizer import generate_plan, write_plan


def test_generate_plan_rebalances_offline_host_tasks_to_online_capacity():
    spec = {
        "hosts": [
            {"name": "ezra", "capacity": 2, "lanes": ["research", "general"]},
            {"name": "bezalel", "capacity": 2, "lanes": ["build", "general"]},
            {"name": "local", "capacity": 1, "lanes": ["general"], "always_available": True},
        ],
        "tasks": [
            {"id": "ISSUE-1", "lane": "build", "priority": 100},
            {"id": "ISSUE-2", "lane": "general", "priority": 80},
            {"id": "ISSUE-3", "lane": "research", "priority": 60},
        ],
    }
    failover_status = {"fleet": {"ezra": "ONLINE", "bezalel": "OFFLINE"}}

    plan = generate_plan(spec, failover_status)

    assignments = {item["task_id"]: item["host"] for item in plan["assignments"]}
    assert assignments == {
        "ISSUE-1": "local",
        "ISSUE-2": "ezra",
        "ISSUE-3": "ezra",
    }
    assert plan["offline_hosts"] == ["bezalel"]
    assert plan["unassigned"] == []


def test_generate_plan_prefers_preferred_host_when_online():
    spec = {
        "hosts": [
            {"name": "ezra", "capacity": 2, "lanes": ["general"]},
            {"name": "bezalel", "capacity": 2, "lanes": ["general"]},
        ],
        "tasks": [
            {"id": "ISSUE-9", "lane": "general", "priority": 100, "preferred_hosts": ["bezalel", "ezra"]},
        ],
    }

    plan = generate_plan(spec, {"fleet": {"ezra": "ONLINE", "bezalel": "ONLINE"}})

    assert plan["assignments"] == [
        {"task_id": "ISSUE-9", "host": "bezalel", "lane": "general", "priority": 100}
    ]


def test_generate_plan_reports_unassigned_when_no_host_matches_lane():
    spec = {
        "hosts": [
            {"name": "ezra", "capacity": 1, "lanes": ["research"]},
        ],
        "tasks": [
            {"id": "ISSUE-5", "lane": "build", "priority": 50},
        ],
    }

    plan = generate_plan(spec, {"fleet": {"ezra": "ONLINE"}})

    assert plan["assignments"] == []
    assert plan["unassigned"] == [
        {"task_id": "ISSUE-5", "reason": "no_online_host_for_lane:build"}
    ]


def test_write_plan_persists_json(tmp_path):
    plan = {
        "assignments": [{"task_id": "ISSUE-1", "host": "ezra", "lane": "general", "priority": 10}],
        "offline_hosts": [],
        "unassigned": [],
    }
    output_path = tmp_path / "dispatch-plan.json"

    write_plan(plan, output_path)

    assert json.loads(output_path.read_text()) == plan