package config

import (
	"bytes"
	"errors"
	"reflect"
	"strings"
	"testing"

	configkit "gitea.maximumdirect.net/eric/ConfigKit"
)

func loadDocumentBytes(content string) (*configkit.Result[Document], error) {
	return configkit.Load(configkit.Bytes("application.yml", []byte(content)), configkit.Options[Document]{
		Definition: documentDefinition(),
	})
}

func TestDocumentDefaultsAndExplicitValues(t *testing.T) {
	defaultsOnly, err := configkit.Load(configkit.NoSource(), configkit.Options[Document]{Definition: documentDefinition()})
	if err != nil {
		t.Fatalf("defaults-only load: %v", err)
	}
	if !reflect.DeepEqual(defaultsOnly.Config, documentDefaults()) || len(defaultsOnly.Sources()) != 0 {
		t.Fatalf("unexpected defaults-only result: %+v sources=%+v", defaultsOnly.Config, defaultsOnly.Sources())
	}

	result, err := loadDocumentBytes(`prompt_dir: ""
profile_dir: ""
schema_dir: ""
transient_retries: 0
server:
  addr: ""
  artifact_root: ""
  max_request_bytes: 0
  max_artifact_bytes: 0
  max_response_bytes: 0
defaults:
  render_format: " JSON "
backends:
  local:
    endpoint: "http://fixture.invalid/v1"
    queue_capacity: 0
    extra_params:
      sample_count: 23
`)
	if err != nil {
		t.Fatalf("explicit-value load: %v", err)
	}
	config := result.Config
	if config.SchemaDir != "" || config.Server.Addr != "" || config.Server.MaxRequestBytes != 0 || config.Server.MaxArtifactBytes != 0 || config.Server.MaxResponseBytes != 0 {
		t.Fatalf("explicit empty and zero values did not replace defaults: %+v", config)
	}
	if config.TransientRetries == nil || *config.TransientRetries != 0 {
		t.Fatalf("explicit zero retry budget lost: %+v", config.TransientRetries)
	}
	if backend := config.Backends["local"]; backend.QueueCapacity == nil || *backend.QueueCapacity != 0 || backend.ExtraParams["sample_count"] != int64(23) {
		t.Fatalf("backend presence or dynamic integer changed: %+v", backend)
	}
	if config.Defaults.RenderFormat != "json" {
		t.Fatalf("render format normalization failed: %q", config.Defaults.RenderFormat)
	}

	nullable, err := loadDocumentBytes("transient_retries: null\nbackends:\n  local:\n    queue_capacity: null\n")
	if err != nil {
		t.Fatalf("nullable-value load: %v", err)
	}
	if nullable.Config.TransientRetries != nil || nullable.Config.Backends["local"].QueueCapacity != nil {
		t.Fatalf("nullable fields did not remain nil: %+v", nullable.Config)
	}

	nullBackends, err := loadDocumentBytes("backends: null\n")
	if err != nil || nullBackends.Config.Backends != nil {
		t.Fatalf("nullable backend map did not remain nil: %+v error=%v", nullBackends, err)
	}
}

func TestDocumentRecordsEffectiveNormalization(t *testing.T) {
	result, err := loadDocumentBytes(`prompt_dir: "  ./one/../two  "
profile_dir: "  "
server:
  artifact_root: " ./data/../artifacts "
  addr: "  :9000  "
defaults:
  render_format: " JSON "
`)
	if err != nil {
		t.Fatalf("load normalized document: %v", err)
	}
	if result.Config.PromptDir != "two" || result.Config.ProfileDir != "" || result.Config.Server.ArtifactRoot != "artifacts" || result.Config.Server.Addr != ":9000" {
		t.Fatalf("unexpected normalized values: %+v", result.Config)
	}
	var effective bytes.Buffer
	if err := result.WriteEffective(&effective); err != nil {
		t.Fatalf("write effective configuration: %v", err)
	}
	for _, fragment := range []string{"prompt_dir: two", "profile_dir: ''", "artifact_root: artifacts", "addr: :9000", "render_format: json"} {
		if !strings.Contains(effective.String(), fragment) {
			t.Fatalf("effective output omitted %q: %s", fragment, effective.String())
		}
	}
	explanation, known := result.Explain(configkit.Keys("prompt_dir"))
	if !known || explanation.Effective.YAML != "two\n" {
		t.Fatalf("explanation does not agree with effective value: %+v known=%t", explanation, known)
	}
	found := false
	for _, change := range explanation.History {
		if change.Origin.Operation == configkit.ChangeNormalization {
			found = true
		}
	}
	if !found {
		t.Fatalf("normalization was not recorded: %+v", explanation.History)
	}
}

func TestDocumentValidationIsSafeAndPathSpecific(t *testing.T) {
	for _, tc := range []struct{ name, content, path string }{
		{"negative retry", "transient_retries: -9173\n", "/transient_retries"},
		{"negative request limit", "server:\n  max_request_bytes: -9173\n", "/server/max_request_bytes"},
		{"negative artifact limit", "server:\n  max_artifact_bytes: -9173\n", "/server/max_artifact_bytes"},
		{"negative response limit", "server:\n  max_response_bytes: -9173\n", "/server/max_response_bytes"},
		{"empty format", "defaults:\n  render_format: \"\"\n", "/defaults/render_format"},
		{"unknown format", "defaults:\n  render_format: private-invalid-value\n", "/defaults/render_format"},
	} {
		t.Run(tc.name, func(t *testing.T) {
			_, err := loadDocumentBytes(tc.content)
			var loadError *configkit.LoadError
			if !errors.As(err, &loadError) {
				t.Fatalf("expected typed validation error, got %v", err)
			}
			found := false
			for _, diagnostic := range loadError.Diagnostics() {
				if diagnostic.Code == configkit.CodeValidateError && diagnostic.Path.String() == tc.path {
					found = true
				}
				if strings.Contains(diagnostic.Message, "9173") || strings.Contains(diagnostic.Message, "private-invalid-value") {
					t.Fatalf("diagnostic disclosed rejected value: %+v", diagnostic)
				}
			}
			if !found {
				t.Fatalf("expected validation at %s, got %+v", tc.path, loadError.Diagnostics())
			}
		})
	}
}

func TestDocumentRejectsNativeShapeErrors(t *testing.T) {
	for _, content := range []string{
		"server: null\n",
		"defaults: null\n",
		"server:\n  addr: null\n",
		"server:\n  max_request_bytes: null\n",
		"defaults:\n  render_format: null\n",
		"server:\n  unknown_field: 1\n",
		"backends:\n  local:\n    unknown_field: 1\n",
	} {
		_, err := loadDocumentBytes(content)
		if err == nil {
			t.Fatalf("unexpected acceptance of %q", content)
		}
	}
}