{%- macro render_content(content, is_system_content=false) %}
    {%- if content is string %}
        {{- content }}
    {%- elif content is iterable and content is not mapping %}
        {%- for item in content %}
            {%- if 'image' in item or 'image_url' in item or item.type == 'image' %}
                {%- if is_system_content %}
                    {{- raise_exception('System message cannot contain images.') }}
                {%- endif %}
                {{- '<|vision_start|><|image_pad|><|vision_end|>' }}
            {%- elif 'video' in item or item.type == 'video' %}
                {%- if is_system_content %}
                    {{- raise_exception('System message cannot contain videos.') }}
                {%- endif %}
                {{- '<|vision_start|><|video_pad|><|vision_end|>' }}
            {%- elif 'text' in item %}
                {{- item.text }}
            {%- else %}
                {{- raise_exception('Unexpected item type in content.') }}
            {%- endif %}
        {%- endfor %}
    {%- elif content is none or content is undefined %}
        {{- '' }}
    {%- else %}
        {{- raise_exception('Unexpected content type.') }}
    {%- endif %}
{%- endmacro %}
{%- if not messages %}
    {{- raise_exception('No messages provided.') }}
{%- endif %}
{%- if tools %}
    {{- raise_exception('This chat template does not support tools.') }}
{%- endif %}
{%- for message in messages %}
    {%- if message.role == 'system' %}
        {%- if not loop.first %}
            {{- raise_exception('System message must be first.') }}
        {%- endif %}
        {{- '<|im_start|>system\n' + render_content(message.content, true) + '<|im_end|>\n' }}
    {%- elif message.role == 'user' or message.role == 'assistant' %}
        {{- '<|im_start|>' + message.role + '\n' + render_content(message.content) + '<|im_end|>\n' }}
    {%- else %}
        {{- raise_exception('Only system/user/assistant roles are supported.') }}
    {%- endif %}
{%- endfor %}
{%- if add_generation_prompt %}
    {{- '<|im_start|>assistant\n' }}
{%- endif %}