package openapi

import (
	"encoding/json"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"testing"

	"gitea.mynodes.xyz/ilker/llmgw/internal/clientapi"
	"gitea.mynodes.xyz/ilker/llmgw/internal/control/adminapi"
)

func repoRoot(t *testing.T) string {
	t.Helper()
	_, file, _, ok := runtime.Caller(0)
	if !ok {
		t.Fatal("cannot locate this test")
	}
	return filepath.Join(filepath.Dir(file), "..", "..", "..")
}

func generated(t *testing.T) map[string]any {
	t.Helper()
	b, err := Generate(repoRoot(t), adminapi.Routes, adminapi.PathParams)
	if err != nil {
		t.Fatal(err)
	}
	var doc map[string]any
	if err := json.Unmarshal(b, &doc); err != nil {
		t.Fatalf("the document is not JSON: %v", err)
	}
	return doc
}

// at walks a decoded document by keys.
func at(t *testing.T, v any, keys ...string) any {
	t.Helper()
	for _, k := range keys {
		m, ok := v.(map[string]any)
		if !ok {
			t.Fatalf("%s: not an object", strings.Join(keys, "."))
		}
		v, ok = m[k]
		if !ok {
			t.Fatalf("no %s (of %s)", k, strings.Join(keys, "."))
		}
	}
	return v
}

func TestTheAdminAPIDocumentIsNotStale(t *testing.T) {
	// Like the configuration reference: a description of the API that is not
	// regenerated describes some earlier week's API, and the server serves the
	// committed copy to every client generated from it.
	want, err := Generate(repoRoot(t), adminapi.Routes, adminapi.PathParams)
	if err != nil {
		t.Fatal(err)
	}
	got, err := os.ReadFile(filepath.Join(repoRoot(t), "docs", "admin-api.openapi.json"))
	if err != nil {
		t.Fatalf("docs/admin-api.openapi.json is missing; run go generate ./internal/docgen: %v", err)
	}
	if string(got) != string(want) {
		t.Error("docs/admin-api.openapi.json no longer matches the admin API's routes and types.\n" +
			"Run: go generate ./internal/docgen")
	}
}

func TestEveryReferenceInTheDocumentResolves(t *testing.T) {
	doc := generated(t)
	var walk func(v any)
	n := 0
	walk = func(v any) {
		switch x := v.(type) {
		case map[string]any:
			if r, ok := x["$ref"].(string); ok {
				n++
				parts := strings.Split(strings.TrimPrefix(r, "#/"), "/")
				at(t, doc, parts...)
			}
			for _, e := range x {
				walk(e)
			}
		case []any:
			for _, e := range x {
				walk(e)
			}
		}
	}
	walk(doc)
	if n < 50 {
		t.Errorf("only %d references; the schemas are not being shared", n)
	}
}

func TestABodyIsDescribedByItsGoType(t *testing.T) {
	doc := generated(t)
	scale := at(t, doc, "paths", "/api/v1/models/{name}/scale", "post")
	if r := at(t, scale, "requestBody", "content", "application/json", "schema", "$ref"); r != "#/components/schemas/ScaleRequest" {
		t.Errorf("scale's body is %v", r)
	}
	props := at(t, doc, "components", "schemas", "ScaleRequest", "properties").(map[string]any)
	// The tag's name, not the field's.
	for _, k := range []string{"min", "max", "idle_timeout"} {
		if _, ok := props[k]; !ok {
			t.Errorf("ScaleRequest has no %s: %v", k, props)
		}
	}
	// The field's comment is its description, and a duration says its unit.
	if d := at(t, props, "max", "description").(string); !strings.Contains(d, "follows Min") {
		t.Errorf("max lost its comment: %q", d)
	}
	if d := at(t, props, "idle_timeout", "description").(string); !strings.Contains(d, "nanoseconds") {
		t.Errorf("idle_timeout does not say it is nanoseconds: %q", d)
	}
	// A type from another package is named with its package.
	if r := at(t, doc, "paths", "/api/v1/models", "post", "requestBody", "content", "application/json", "schema", "$ref"); r != "#/components/schemas/catalog.Model" {
		t.Errorf("adding a model takes %v", r)
	}
}

func TestAnEmbeddedStructsFieldsAreItsOwn(t *testing.T) {
	// CapacityView embeds bench.Capacity, and encoding/json writes the
	// embedded fields at the top level: so must the schema.
	doc := generated(t)
	props := at(t, doc, "components", "schemas", "CapacityView", "properties").(map[string]any)
	for _, k := range []string{"measured_by", "model", "profile"} {
		if _, ok := props[k]; !ok {
			t.Errorf("CapacityView has no %s: %v", k, props)
		}
	}
}

func TestEveryChangeNeedsTheTokenAndNamesItsActor(t *testing.T) {
	doc := generated(t)
	if s := at(t, doc, "components", "securitySchemes", "adminToken", "scheme"); s != "bearer" {
		t.Errorf("scheme %v", s)
	}
	if len(at(t, doc, "security").([]any)) != 1 {
		t.Error("the token is not required document-wide")
	}
	del := at(t, doc, "paths", "/api/v1/models/{name}", "delete")
	found := false
	for _, p := range at(t, del, "parameters").([]any) {
		if p.(map[string]any)["$ref"] == "#/components/parameters/Actor" {
			found = true
		}
	}
	if !found {
		t.Error("removing a model does not take X-Llmgw-Actor")
	}
	if _, ok := at(t, del, "responses").(map[string]any)["401"]; !ok {
		t.Error("removing a model does not say it can be refused for the token")
	}
}

func TestAPathParameterWithNoDescriptionIsAnError(t *testing.T) {
	routes := []adminapi.Route{{Method: "GET", Path: "/api/v1/things/{id}", Summary: "x", Response: adminapi.Result{}}}
	if _, err := Generate(repoRoot(t), routes, adminapi.PathParams); err == nil {
		t.Error("a parameter nobody described was let through")
	}
}

func TestTheClientAPIDocumentIsNotStaleAndDescribesWhatClientsSend(t *testing.T) {
	want, err := GenerateDoc(repoRoot(t), Client, clientapi.Routes, clientapi.PathParams)
	if err != nil {
		t.Fatal(err)
	}
	got, err := os.ReadFile(filepath.Join(repoRoot(t), "docs", "client-api.openapi.json"))
	if err != nil || string(got) != string(want) {
		t.Fatal("docs/client-api.openapi.json no longer matches the client API's routes and types.\n" +
			"Run: go generate ./internal/docgen")
	}
	var doc map[string]any
	if err := json.Unmarshal(want, &doc); err != nil {
		t.Fatal(err)
	}
	chat := at(t, doc, "paths", "/v1/chat/completions", "post")
	if at(t, chat, "requestBody", "content", "application/json", "schema", "$ref") != "#/components/schemas/ChatCompletionRequest" {
		t.Error("chat's body is not its request type")
	}
	if _, ok := at(t, chat, "responses", "200", "content").(map[string]any)["text/event-stream"]; !ok {
		t.Error("chat does not say it may stream")
	}
	if _, ok := at(t, doc, "paths", "/v1/files", "post", "requestBody", "content").(map[string]any)["multipart/form-data"]; !ok {
		t.Error("an upload is not a form")
	}
	if at(t, doc, "paths", "/v1/3d/generations", "post", "responses", "202", "description") == nil {
		t.Error("a 3D job is not answered 202")
	}
	if _, ok := at(t, doc, "components", "securitySchemes").(map[string]any)["apiKey"]; !ok {
		t.Error("no API key scheme")
	}
	// The admin API's actor header is the admin API's.
	if _, ok := at(t, doc, "components").(map[string]any)["parameters"]; ok {
		t.Error("the client API takes the admin API's X-Llmgw-Actor")
	}
}