{%- if messages[0]["role"] == "system" %}
    {%- set system_message = messages[0]["content"] %}
    {%- set loop_messages = messages[1:] %}
{%- else %}
    {%- set loop_messages = messages %}
{%- endif %}
{%- if not tools is defined %}
    {%- set tools = none %}
{%- endif %}
{%- set user_messages = loop_messages | selectattr("role", "equalto", "user") | list %}

{#- This block checks for alternating user/assistant messages, skipping tool calling messages #}
{%- set ns = namespace() %}
{%- set ns.index = 0 %}
{%- for message in loop_messages %}
    {%- if not (message.role == "tool" or message.role == "tool_results" or (message.tool_calls is defined and message.tool_calls is not none)) %}
        {%- if (message["role"] == "user") != (ns.index % 2 == 0) %}
            {{- raise_exception("After the optional system message, conversation roles must alternate user/assistant/user/assistant/...") }}
        {%- endif %}
        {%- set ns.index = ns.index + 1 %}
    {%- endif %}
{%- endfor %}

{{- bos_token }}
{%- for message in loop_messages %}
    {%- if message["role"] == "user" %}
        {%- if tools is not none and (message == user_messages[-1]) %}
            {{- "[AVAILABLE_TOOLS] [" }}
            {%- for tool in tools %}
                {%- set tool = tool.function %}
                {{- '{"type": "function", "function": {' }}
                {%- for key, val in tool.items() if key != "return" %}
                    {%- if val is string %}
                        {{- '"' + key + '": "' + val + '"' }}
                    {%- else %}
                        {{- '"' + key + '": ' + val|tojson }}
                    {%- endif %}
                    {%- if not loop.last %}
                        {{- ", " }}
                    {%- endif %}
                {%- endfor %}
                {{- "}}" }}
                {%- if not loop.last %}
                    {{- ", " }}
                {%- else %}
                    {{- "]" }}
                {%- endif %}
            {%- endfor %}
            {{- "[/AVAILABLE_TOOLS]" }}
            {%- endif %}
        {%- if loop.last and system_message is defined %}
            {{- "
 " + system_message + "\n\n" + message["content"] + "
" }}
        {%- else %}
            {{- "
 " + message["content"] + "
" }}
        {%- endif %}
    {%- elif message.tool_calls is defined and message.tool_calls is not none %}
        {{- "[TOOL_CALLS] [" }}
        {%- for tool_call in message.tool_calls %}
            {%- set out = tool_call.function|tojson %}
            {{- out[:-1] }}
            {%- if not tool_call.id is defined or tool_call.id|length != 9 %}
                {{- raise_exception("Tool call IDs should be alphanumeric strings with length 9!") }}
            {%- endif %}
            {{- ', "id": "' + tool_call.id + '"}' }}
            {%- if not loop.last %}
                {{- ", " }}
            {%- else %}
                {{- "]" + eos_token }}
            {%- endif %}
        {%- endfor %}
    {%- elif message["role"] == "assistant" %}
        {{- " " + message["content"]|trim + eos_token}}
    {%- elif message["role"] == "tool_results" or message["role"] == "tool" %}
        {%- if message.content is defined and message.content.content is defined %}
            {%- set content = message.content.content %}
        {%- else %}
            {%- set content = message.content %}
        {%- endif %}
        {{- '[TOOL_RESULTS] {"content": ' + content|string + ", " }}
        {%- if not message.tool_call_id is defined or message.tool_call_id|length != 9 %}
            {{- raise_exception("Tool call IDs should be alphanumeric strings with length 9!") }}
        {%- endif %}
        {{- '"call_id": "' + message.tool_call_id + '"}[/TOOL_RESULTS]' }}
    {%- else %}
        {{- raise_exception("Only user and assistant roles are supported, with the exception of an initial optional system message!") }}
    {%- endif %}
{%- endfor %}