package config

import (
	"errors"
	"os"
	"path/filepath"
	"testing"

	renderformat "gitea.maximumdirect.net/eric/scriptorium/internal/format"
)

func TestLoadConfigMissingImplicitPathUsesBuiltInDefaults(t *testing.T) {
	tmp := t.TempDir()
	missing := filepath.Join(tmp, "missing.yml")

	got, err := LoadConfig(missing, false)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}

	want := BuiltInDefaults()
	if got != want {
		t.Fatalf("unexpected settings: got=%+v want=%+v", got, want)
	}
}

func TestLoadConfigMissingExplicitPathReturnsError(t *testing.T) {
	tmp := t.TempDir()
	missing := filepath.Join(tmp, "missing.yml")

	_, err := LoadConfig(missing, true)
	if err == nil {
		t.Fatal("expected error for missing explicit config")
	}
	if !errors.Is(err, ErrConfigNotFound) {
		t.Fatalf("expected ErrConfigNotFound, got %v", err)
	}
}

func TestLoadConfigInvalidYAMLReturnsError(t *testing.T) {
	path := writeConfigFile(t, "config.yml", "prompt_dir: [")

	_, err := LoadConfig(path, true)
	if err == nil {
		t.Fatal("expected invalid YAML error")
	}
	if !errors.Is(err, ErrInvalidConfigYAML) {
		t.Fatalf("expected ErrInvalidConfigYAML, got %v", err)
	}
}

func TestLoadConfigInvalidYAMLImplicitPathReturnsError(t *testing.T) {
	path := writeConfigFile(t, "config.yml", "prompt_dir: [")

	_, err := LoadConfig(path, false)
	if err == nil {
		t.Fatal("expected invalid YAML error")
	}
	if !errors.Is(err, ErrInvalidConfigYAML) {
		t.Fatalf("expected ErrInvalidConfigYAML, got %v", err)
	}
}

func TestLoadConfigUnknownFieldReturnsError(t *testing.T) {
	path := writeConfigFile(t, "config.yml", "unknown_field: true\n")

	_, err := LoadConfig(path, true)
	if err == nil {
		t.Fatal("expected unknown field error")
	}
	if !errors.Is(err, ErrInvalidConfigYAML) {
		t.Fatalf("expected ErrInvalidConfigYAML, got %v", err)
	}
}

func TestLoadConfigAPIKeyFieldIsRejectedAsUnknown(t *testing.T) {
	path := writeConfigFile(t, "config.yml", "api_key: secret\n")

	_, err := LoadConfig(path, true)
	if err == nil {
		t.Fatal("expected unknown field error for api_key")
	}
	if !errors.Is(err, ErrInvalidConfigYAML) {
		t.Fatalf("expected ErrInvalidConfigYAML, got %v", err)
	}
}

func TestLoadConfigValidConfigSetsDirectoriesAndServerAddr(t *testing.T) {
	path := writeConfigFile(t, "config.yml", `
prompt_dir: ./prompts
profile_dir: ./profiles
schema_dir: ./schemas
server:
  addr: 127.0.0.1:9090
defaults:
  render_format: json
`)

	got, err := LoadConfig(path, true)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}

	if got.PromptDir != filepath.Clean("./prompts") {
		t.Fatalf("unexpected prompt_dir: %q", got.PromptDir)
	}
	if got.ProfileDir != filepath.Clean("./profiles") {
		t.Fatalf("unexpected profile_dir: %q", got.ProfileDir)
	}
	if got.SchemaDir != filepath.Clean("./schemas") {
		t.Fatalf("unexpected schema_dir: %q", got.SchemaDir)
	}
	if got.ServerAddr != "127.0.0.1:9090" {
		t.Fatalf("unexpected server.addr: %q", got.ServerAddr)
	}
	if got.DefaultRenderFormat != renderformat.PreparedRunFormatJSON {
		t.Fatalf("unexpected defaults.render_format: %q", got.DefaultRenderFormat)
	}
}

func TestLoadConfigEmptyFileResolvesToBuiltInDefaults(t *testing.T) {
	path := writeConfigFile(t, "config.yml", "")

	got, err := LoadConfig(path, true)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}

	want := BuiltInDefaults()
	if got != want {
		t.Fatalf("unexpected settings: got=%+v want=%+v", got, want)
	}
}

func TestLoadConfigImplicitSearchPrefersUsrLocalEtcOverEtc(t *testing.T) {
	tmp := t.TempDir()
	localPath := filepath.Join(tmp, "usr-local.yml")
	etcPath := filepath.Join(tmp, "etc.yml")

	if err := os.WriteFile(localPath, []byte("prompt_dir: ./from-usr-local\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(etcPath, []byte("prompt_dir: ./from-etc\n"), 0o644); err != nil {
		t.Fatal(err)
	}

	orig := defaultConfigSearchPaths
	defaultConfigSearchPaths = []string{localPath, etcPath}
	t.Cleanup(func() { defaultConfigSearchPaths = orig })

	got, err := LoadConfig("", false)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	if got.PromptDir != filepath.Clean("./from-usr-local") {
		t.Fatalf("expected usr-local config to win, got prompt_dir=%q", got.PromptDir)
	}
}

func TestLoadConfigImplicitSearchFallsBackToEtcWhenUsrLocalMissing(t *testing.T) {
	tmp := t.TempDir()
	missingLocal := filepath.Join(tmp, "missing-local.yml")
	etcPath := filepath.Join(tmp, "etc.yml")

	if err := os.WriteFile(etcPath, []byte("prompt_dir: ./from-etc\n"), 0o644); err != nil {
		t.Fatal(err)
	}

	orig := defaultConfigSearchPaths
	defaultConfigSearchPaths = []string{missingLocal, etcPath}
	t.Cleanup(func() { defaultConfigSearchPaths = orig })

	got, err := LoadConfig("", false)
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}
	if got.PromptDir != filepath.Clean("./from-etc") {
		t.Fatalf("expected etc fallback config, got prompt_dir=%q", got.PromptDir)
	}
}

func TestApplyCLIOverridesAppliesPrecedence(t *testing.T) {
	base := AppSettings{
		PromptDir:           "/from/config/prompts",
		ProfileDir:          "/from/config/profiles",
		SchemaDir:           "/from/config/schemas",
		ServerAddr:          ":1234",
		DefaultRenderFormat: renderformat.PreparedRunFormatJSON,
	}

	got, err := ApplyCLIOverrides(base, CLIOverrides{
		PromptDir:    "./prompts-cli",
		ProfileDir:   "./profiles-cli",
		SchemaDir:    "./schemas-cli",
		ServerAddr:   ":8081",
		RenderFormat: "text",
	})
	if err != nil {
		t.Fatalf("expected no error, got %v", err)
	}

	if got.PromptDir != filepath.Clean("./prompts-cli") {
		t.Fatalf("unexpected prompt dir: %q", got.PromptDir)
	}
	if got.ProfileDir != filepath.Clean("./profiles-cli") {
		t.Fatalf("unexpected profile dir: %q", got.ProfileDir)
	}
	if got.SchemaDir != filepath.Clean("./schemas-cli") {
		t.Fatalf("unexpected schema dir: %q", got.SchemaDir)
	}
	if got.ServerAddr != ":8081" {
		t.Fatalf("unexpected server addr: %q", got.ServerAddr)
	}
	if got.DefaultRenderFormat != renderformat.PreparedRunFormatText {
		t.Fatalf("unexpected render format: %q", got.DefaultRenderFormat)
	}
}

func TestApplyCLIOverridesInvalidRenderFormatReturnsError(t *testing.T) {
	_, err := ApplyCLIOverrides(BuiltInDefaults(), CLIOverrides{RenderFormat: "yaml"})
	if err == nil {
		t.Fatal("expected invalid render format error")
	}
	if !errors.Is(err, ErrInvalidConfig) {
		t.Fatalf("expected ErrInvalidConfig, got %v", err)
	}
}

func writeConfigFile(t *testing.T, name, content string) string {
	t.Helper()
	path := filepath.Join(t.TempDir(), name)
	if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
		t.Fatalf("failed to write config file: %v", err)
	}
	return path
}