package openapi

import (
	"os"
	"testing"

	"go.yaml.in/yaml/v4"
)

type document struct {
	OpenAPI    string                    `yaml:"openapi"`
	Paths      map[string]map[string]any `yaml:"paths"`
	Components map[string]any            `yaml:"components"`
}

func TestDistributionContract(t *testing.T) {
	spec := readDocument(t, "proxy-pool.yaml")
	if spec.OpenAPI != "3.1.0" {
		t.Fatalf("openapi version = %q, want 3.1.0", spec.OpenAPI)
	}
	extraction, ok := spec.Paths["/api/v1/proxies/extract"]
	if !ok {
		t.Fatal("exclusive extraction path is missing")
	}
	post, ok := extraction["post"]
	if !ok {
		t.Fatal("exclusive extraction must use POST")
	}
	requireResponses(t, post, "200", "400", "409", "413", "415", "422", "429", "500", "503")
	for path := range spec.Paths {
		if path == "/api/v1/leases" || path == "/api/v1/proxies/release" || path == "/api/v1/proxies/renew" {
			t.Fatalf("lease/release path is forbidden: %s", path)
		}
	}
}

func TestAdminContract(t *testing.T) {
	spec := readDocument(t, "admin.yaml")
	for _, path := range []string{
		"/api/v1/status",
		"/api/v1/audit",
		"/api/v1/upstreams/{name}/enable",
		"/api/v1/upstreams/{name}/disable",
		"/api/v1/routing/{name}/switch",
		"/api/v1/config/reload",
	} {
		if _, ok := spec.Paths[path]; !ok {
			t.Errorf("admin path is missing: %s", path)
		}
	}
	requireResponses(t, spec.Paths["/api/v1/routing/{name}/switch"]["post"],
		"200", "400", "401", "403", "404", "405", "409", "413", "415", "422", "500", "503")
	requireResponses(t, spec.Paths["/api/v1/audit"]["get"],
		"200", "400", "401", "403", "405", "500", "503")
	requireAuditPaginationContract(t, spec.Paths["/api/v1/audit"]["get"])
	requireAuditSchemas(t, spec)
}

func requireAuditPaginationContract(t *testing.T, operation any) {
	t.Helper()
	operationMap, ok := operation.(map[string]any)
	if !ok {
		t.Fatalf("audit operation has type %T, want map", operation)
	}
	parameters, ok := operationMap["parameters"].([]any)
	if !ok {
		t.Fatalf("audit parameters has type %T, want array", operationMap["parameters"])
	}
	afterID := parameterSchema(t, parameters, "afterId")
	if afterID["type"] != "integer" || afterID["minimum"] != 0 || afterID["default"] != 0 {
		t.Errorf("afterId schema = %#v, want integer with minimum/default 0", afterID)
	}
	limit := parameterSchema(t, parameters, "limit")
	if limit["type"] != "integer" || limit["minimum"] != 1 || limit["maximum"] != 1000 || limit["default"] != 100 {
		t.Errorf("limit schema = %#v, want integer [1, 1000] with default 100", limit)
	}
}

func parameterSchema(t *testing.T, parameters []any, name string) map[string]any {
	t.Helper()
	for _, raw := range parameters {
		parameter, ok := raw.(map[string]any)
		if !ok || parameter["name"] != name || parameter["in"] != "query" {
			continue
		}
		schema, ok := parameter["schema"].(map[string]any)
		if !ok {
			t.Fatalf("%s parameter schema has type %T, want map", name, parameter["schema"])
		}
		return schema
	}
	t.Fatalf("query parameter %q is missing", name)
	return nil
}

func requireAuditSchemas(t *testing.T, spec document) {
	t.Helper()
	schemas, ok := spec.Components["schemas"].(map[string]any)
	if !ok {
		t.Fatal("components.schemas is missing")
	}
	for _, name := range []string{"AuditPage", "AuditRecord"} {
		if _, ok := schemas[name].(map[string]any); !ok {
			t.Errorf("schema %s is missing", name)
		}
	}
	record, _ := schemas["AuditRecord"].(map[string]any)
	properties, _ := record["properties"].(map[string]any)
	for _, forbidden := range []string{"proxy", "upstreamUrl", "credential", "activePool"} {
		if _, exists := properties[forbidden]; exists {
			t.Errorf("AuditRecord must not expose %q", forbidden)
		}
	}
}

func requireResponses(t *testing.T, operation any, codes ...string) {
	t.Helper()
	operationMap, ok := operation.(map[string]any)
	if !ok {
		t.Fatalf("operation has type %T, want map", operation)
	}
	responses, ok := operationMap["responses"].(map[string]any)
	if !ok {
		t.Fatalf("responses has type %T, want map", operationMap["responses"])
	}
	for _, code := range codes {
		if _, ok := responses[code]; !ok {
			t.Errorf("response %s is missing", code)
		}
	}
}

func readDocument(t *testing.T, path string) document {
	t.Helper()
	content, err := os.ReadFile(path)
	if err != nil {
		t.Fatalf("read %s: %v", path, err)
	}
	var spec document
	if err := yaml.Unmarshal(content, &spec); err != nil {
		t.Fatalf("parse %s: %v", path, err)
	}
	if spec.OpenAPI != "3.1.0" {
		t.Fatalf("%s openapi version = %q, want 3.1.0", path, spec.OpenAPI)
	}
	return spec
}