{% import 'helpers.j2' as h -%}

{%- macro instrument_default(metric) -%}
{%- set ns = namespace(value="Int64", inst="unknown") -%}
{%- set divisible = ["s", "ms"] -%}
{%- if metric.unit is in divisible -%}
{%- set ns.value="Float64" -%}
{%- endif -%}
{%- if metric.instrument == "counter" -%}
{%- set ns.inst="Counter" -%}
{%- elif metric.instrument == "updowncounter" -%}
{%- set ns.inst="UpDownCounter" -%}
{%- elif metric.instrument == "gauge" -%}
{%- set ns.inst="Gauge" -%}
{%- elif metric.instrument == "histogram" -%}
{%- set ns.inst="Histogram" -%}
{%- endif -%}
{{ ns.value ~ ns.inst }}
{%- endmacro -%}

{%- macro instrument(metric) -%}
{{ metric.metric_name | map_text("instrument", instrument_default(metric)) }}
{%- endmacro -%}

{%- macro value_type(metric) -%}
{%- if instrument(metric)[:7] == "Float64" -%}
Float64
{%- else -%}
Int64
{%- endif -%}
{%- endmacro -%}

{%- macro param_name(raw="", pkg="") -%}
{%- set reserved = [
	"type", "break", "default", "func", "interface", "select", "case", "defer",
	"go", "map", "struct", "chan", "else", "goto", "const", "fallthrough", "if",
	"range", "type", "continue", "for", "import", "return", "var",
]-%}
{%- set name = raw -%}
{%- if pkg != "" -%}
{%- set n = pkg | length -%}
{%- if pkg == name[:n] -%}
{%- set name = name[n:] -%}
{%- if name[0] == "." or name[0] == "." -%}
{%- set name = name[1:] -%}
{%- endif -%}
{%- endif -%}
{%- endif -%}
{%- if name | lower is in reserved -%}
{{ raw | camel_case }}
{%- else -%}
{{ name | camel_case }}
{%- endif -%}
{%- endmacro -%}

{%- macro params_docs(attrs, pkg="") -%}
{%- set ns = namespace(output='') -%}
{%- for attr in attrs | required | attribute_sort -%}
	{%- set ns.output = ns.output ~  "\n\nThe " ~ param_name(attr.name, pkg) ~ " is the " ~ h.lower_first(attr.brief) -%}
{%- endfor -%}
{%- if attrs | not_required | length > 0 -%}
	{%- set ns.output = ns.output ~ "\n\nAll additional attrs passed are included in the recorded value." -%}
{%- endif -%}
{%- if ns.output != "" -%}
//
{{ ns.output | comment }}
{%- endif -%}
{%- endmacro -%}

{%- macro param(attr, pkg="") -%}
{%- if attr.type is mapping -%}
{{ param_name(attr.name, pkg) }} {{ h.to_go_name(attr.name, pkg) }}Attr,
{%- else -%}
{{ param_name(attr.name, pkg) }} {{ attr.type | map_text("attribute_type_value")}},
{%- endif -%}
{%- endmacro -%}

{%- macro params(attrs, type="", pkg="", prefix="") -%}
{%- for attr in attrs | required | attribute_sort -%}
{{ prefix ~ param(attr, pkg) }}
{% endfor -%}
{{ prefix ~ "attrs ...attribute.KeyValue," }}
{%- endmacro -%}

{%- macro to_attribute(attr, pkg="") -%}
{%- if attr.type is mapping -%}
	attribute.{{ h.attr_type(attr) | map_text("attribute_type_method")}}("{{ attr.name }}", {{ h.member_type(attr.type.members[0]) }}({{ param_name(attr.name, pkg) }})),
{%- else -%}
	attribute.{{ attr.type | map_text("attribute_type_method")}}("{{ attr.name }}", {{ param_name(attr.name, pkg) }}),
{%- endif -%}
{%- endmacro -%}

{%- macro with_attributes_opt(attrs, pkg="", prefix="") -%}
{%- if attrs | length > 0 -%}
{{ prefix }}metric.WithAttributes(
{%- if attrs | required | length > 0 %}
{{ prefix }}	append(
{{ prefix }}		attrs,
{%- for attr in attrs | required | attribute_sort %}
{{ prefix }}		{{ to_attribute(attr, pkg) }}
{%- endfor %}
{{ prefix }}	)...,
{%- else %}
{{ prefix }}	attrs...,
{%- endif %}
{{ prefix }}),
{%- endif -%}
{%- endmacro -%}

{%- macro add_method_with_optional(metric, inst, pkg="") -%}
{%- set name = h.to_go_name(metric.metric_name, pkg) -%}
{%- set req_attr = metric.attributes | required | attribute_sort -%}
func (m {{ name }}) Add(
	ctx context.Context,
	incr {{ value_type(metric) | lower }},
{{ params(metric.attributes, pkg=pkg, prefix="\t") }}
) {
	o := addOptPool.Get().(*[]metric.AddOption)
	defer func() {
		*o = (*o)[:0]
		addOptPool.Put(o)
	}()

	*o = append(
		*o,
{{ with_attributes_opt(metric.attributes, pkg=pkg, prefix="\t\t") }}
	)

	m.{{ inst }}.Add(ctx, incr, *o...)
}
{%- endmacro -%}

{%- macro add_method(metric, inst, pkg="") -%}

// Add adds incr to the existing count.
{%- if metric.attributes | length > 0 %}
{{ params_docs(metric.attributes, pkg=pkg) }}
{%- if metric.note is defined %}
//
{{ metric.note | comment }}
{%- endif %}
{{ add_method_with_optional(metric, inst, pkg) }}
{%- else %}
{%- if metric.note is defined %}
//
{{ metric.note | comment }}
{%- endif %}
func (m {{ h.to_go_name(metric.metric_name, pkg) }}) Add(ctx context.Context, incr {{ value_type(metric) | lower }}, attrs ...attribute.KeyValue) {
	if len(attrs) == 0 {
		m.{{ inst }}.Add(ctx, incr)
		return
	}

	o := addOptPool.Get().(*[]metric.AddOption)
	defer func() {
		*o = (*o)[:0]
		addOptPool.Put(o)
	}()

	*o = append(*o, metric.WithAttributes(attrs...))
	m.{{ inst }}.Add(ctx, incr, *o...)
}
{%- endif -%}
{%- endmacro -%}

{%- macro record_method_with_optional(metric, inst, pkg="") -%}
{%- set name = h.to_go_name(metric.metric_name, pkg) -%}
{%- set req_attr = metric.attributes | required | attribute_sort -%}
func (m {{ name }}) Record(
	ctx context.Context,
	val {{ value_type(metric) | lower }},
{{ params(metric.attributes, pkg=pkg, prefix="\t") }}
) {
	o := recOptPool.Get().(*[]metric.RecordOption)
	defer func() {
		*o = (*o)[:0]
		recOptPool.Put(o)
	}()

	*o = append(
		*o,
{{ with_attributes_opt(metric.attributes, pkg=pkg, prefix="\t\t") }}
	)

	m.{{ inst }}.Record(ctx, val, *o...)
}
{%- endmacro -%}

{%- macro record_method(metric, inst, pkg="") -%}

// Record records val to the current distribution.
{%- if metric.attributes | length > 0 %}
{{ params_docs(metric.attributes, pkg=pkg) }}
{%- if metric.note is defined %}
//
{{ metric.note | comment }}
{%- endif %}
{{ record_method_with_optional(metric, inst, pkg) }}
{%- else %}
{%- set name = h.to_go_name(metric.metric_name, pkg) -%}
{%- if metric.note is defined %}
//
{{ metric.note | comment }}
{%- endif %}
func (m {{ name }}) Record(ctx context.Context, val {{ value_type(metric) | lower }}, attrs ...attribute.KeyValue) {
	if len(attrs) == 0 {
		m.{{ inst }}.Record(ctx, val)
	}

	o := recOptPool.Get().(*[]metric.RecordOption)
	defer func() {
		*o = (*o)[:0]
		recOptPool.Put(o)
	}()

	*o = append(*o, metric.WithAttributes(attrs...))
	m.{{ inst }}.Record(ctx, val, *o...)
}
{%- endif -%}
{%- endmacro -%}
