based on: [https://github.com/chujiezheng/chat_templates/blob/main/chat_templates/chatqa.jinja]

{% if messages[0]['role'] == 'system' %}
    {% set system_message = 'System: ' + messages[0]['content'] | trim %}
    {% set messages = messages[1:] %}
{% else %}
    {% set system_message = '' %}
{% endif %}

{% if messages[0]['role'] == 'context' %}
    {% set context_message = '

' + messages[0]['content'] | trim %}
    {% set messages = messages[1:] %}
{% else %}
    {% set context_message = '' %}
{% endif %}

{{ bos_token + system_message + context_message}}
{% for message in messages %}
    {% if (message['role'] == 'user') != (loop.index0 % 2 == 0) %}
        {{ raise_exception('Conversation roles must alternate user/assistant/user/assistant/...') }}
    {% endif %}

    {% if message['role'] == 'user' %}
        {{ '

User: ' + message['content'] | trim }}
    {% elif message['role'] == 'assistant' %}
        {{ '

Assistant: '  + message['content'] | trim }}
    {% endif %}
{% endfor %}

{% if add_generation_prompt %}
    {{ '

Assistant:' }}
{% endif %}