package config

import (
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"
)

func TestLoadExpandsEnvAndDefaults(t *testing.T) {
	dir := t.TempDir()
	t.Setenv("AGENTU_TEST_KEY", "sk-test")
	path := filepath.Join(dir, "agentu.yaml")
	if err := os.WriteFile(path, []byte(`
providers:
  test:
    base_url: https://example.com
    api_key: ${AGENTU_TEST_KEY}
    models:
      - id: test-model
agent:
  working_dir: .
`), 0o644); err != nil {
		t.Fatal(err)
	}

	cfg, err := Load(path)
	if err != nil {
		t.Fatal(err)
	}
	provider := cfg.Providers[cfg.DefaultProviderName()]
	if provider.APIKey != "sk-test" {
		t.Fatalf("api key = %q", provider.APIKey)
	}
	if providerName := cfg.DefaultProviderName(); providerName != "test" {
		t.Fatalf("default provider = %q", providerName)
	}
	if cfg.Agent.ToolTimeout != 30*time.Second {
		t.Fatalf("tool timeout = %s", cfg.Agent.ToolTimeout)
	}
	if !filepath.IsAbs(cfg.Agent.WorkingDir) {
		t.Fatalf("working dir is not absolute: %s", cfg.Agent.WorkingDir)
	}
}

func TestLoadMinimalModelObjectConfig(t *testing.T) {
	dir := t.TempDir()
	t.Setenv("AGENTU_TEST_KEY", "sk-test")
	path := filepath.Join(dir, "agentu.yaml")
	if err := os.WriteFile(path, []byte(`
providers:
  test:
    base_url: https://example.com
    api_key: ${AGENTU_TEST_KEY}
    models:
      - id: model-a
        thinking: none
        context: 256000
`), 0o644); err != nil {
		t.Fatal(err)
	}

	cfg, err := Load(path)
	if err != nil {
		t.Fatal(err)
	}
	provider := cfg.Providers["test"]
	if provider.Model != "model-a" {
		t.Fatalf("model = %q", provider.Model)
	}
	if len(provider.Models) != 1 || provider.Models[0] != "model-a" {
		t.Fatalf("models = %#v", provider.Models)
	}
	if provider.ContextTokens != 256000 {
		t.Fatalf("context tokens = %d", provider.ContextTokens)
	}
	if !provider.ThinkingConfigured || provider.Thinking != "none" || provider.ThinkingParam != "thinking" {
		t.Fatalf("thinking config = %#v", provider)
	}
	if cfg.Agent.ToolTimeout != 30*time.Second {
		t.Fatalf("tool timeout = %s", cfg.Agent.ToolTimeout)
	}
	if cfg.Agent.SystemPrompt == "" {
		t.Fatal("system prompt default was not applied")
	}
}

func TestLoadRejectsStringModelEntries(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "agentu.yaml")
	if err := os.WriteFile(path, []byte(`
providers:
  test:
    base_url: https://example.com
    api_key: sk-test
    models:
      - test-model
`), 0o644); err != nil {
		t.Fatal(err)
	}

	_, err := Load(path)
	if err == nil || !strings.Contains(err.Error(), "cannot unmarshal") {
		t.Fatalf("err = %v", err)
	}
}

func TestLoadMaxContextTokens(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "agentu.yaml")
	if err := os.WriteFile(path, []byte(`
providers:
  test:
    base_url: https://example.com
    api_key: sk-test
    models:
      - id: test-model
agent:
  max_context_tokens: 120000
`), 0o644); err != nil {
		t.Fatal(err)
	}

	cfg, err := Load(path)
	if err != nil {
		t.Fatal(err)
	}
	if cfg.Agent.MaxContextTokens != 120000 {
		t.Fatalf("max context tokens = %d", cfg.Agent.MaxContextTokens)
	}
}

func TestLoadRejectsNegativeMaxContextTokens(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "agentu.yaml")
	if err := os.WriteFile(path, []byte(`
providers:
  test:
    base_url: https://example.com
    api_key: sk-test
    models:
      - id: test-model
agent:
  max_context_tokens: -1
`), 0o644); err != nil {
		t.Fatal(err)
	}

	_, err := Load(path)
	if err == nil || !strings.Contains(err.Error(), "agent.max_context_tokens") {
		t.Fatalf("err = %v", err)
	}
}

func TestLoadUsesDefaultConfigPath(t *testing.T) {
	dir := t.TempDir()
	t.Setenv("HOME", dir)
	t.Setenv("AGENTU_TEST_KEY", "sk-test")
	configDir := filepath.Join(dir, ".agentu")
	if err := os.MkdirAll(configDir, 0o755); err != nil {
		t.Fatal(err)
	}
	path := filepath.Join(configDir, "config.yaml")
	if err := os.WriteFile(path, []byte(`
providers:
  test:
    base_url: https://example.com
    api_key: ${AGENTU_TEST_KEY}
    models:
      - id: test-model
`), 0o644); err != nil {
		t.Fatal(err)
	}

	cfg, err := Load("")
	if err != nil {
		t.Fatal(err)
	}
	if got := cfg.DefaultProviderName(); got != "test" {
		t.Fatalf("default provider = %q", got)
	}
}

func TestResolvePathExpandsHome(t *testing.T) {
	dir := t.TempDir()
	t.Setenv("HOME", dir)

	got, err := ResolvePath("~/.agentu/config.yaml")
	if err != nil {
		t.Fatal(err)
	}
	want := filepath.Join(dir, ".agentu", "config.yaml")
	if got != want {
		t.Fatalf("path = %q, want %q", got, want)
	}
}

func TestLoadDefaultSystemPromptDiscouragesEagerTools(t *testing.T) {
	dir := t.TempDir()
	t.Setenv("AGENTU_TEST_KEY", "sk-test")
	path := filepath.Join(dir, "agentu.yaml")
	if err := os.WriteFile(path, []byte(`
providers:
  test:
    base_url: https://example.com
    api_key: ${AGENTU_TEST_KEY}
    models:
      - id: test-model
`), 0o644); err != nil {
		t.Fatal(err)
	}

	cfg, err := Load(path)
	if err != nil {
		t.Fatal(err)
	}
	for _, want := range []string{"Answer simple conversation directly", "Use tools only when"} {
		if !strings.Contains(cfg.Agent.SystemPrompt, want) {
			t.Fatalf("system prompt missing %q: %s", want, cfg.Agent.SystemPrompt)
		}
	}
}

func TestLoadMultiProviderConfig(t *testing.T) {
	dir := t.TempDir()
	t.Setenv("AGENTU_TEST_KEY", "sk-test")
	path := filepath.Join(dir, "agentu.yaml")
	if err := os.WriteFile(path, []byte(`
providers:
  loveuer:
    base_url: https://example.com
    api_key: ${AGENTU_TEST_KEY}
    models:
      - id: model-a
        thinking: xhigh
      - id: model-b
  backup:
    base_url: https://backup.example.com
    api_key: ${AGENTU_TEST_KEY}
    models:
      - id: model-c
`), 0o644); err != nil {
		t.Fatal(err)
	}

	cfg, err := Load(path)
	if err != nil {
		t.Fatal(err)
	}
	if got := cfg.DefaultProviderName(); got != "backup" {
		t.Fatalf("default provider = %q", got)
	}
	provider := cfg.Providers["loveuer"]
	if got := provider.Model; got != "model-a" {
		t.Fatalf("active model = %q", got)
	}
	if got := cfg.Providers["backup"].Model; got != "model-c" {
		t.Fatalf("backup default model = %q", got)
	}
	if !provider.ThinkingConfigured || provider.Thinking != "xhigh" || provider.ThinkingParam != "thinking" {
		t.Fatalf("thinking config = %#v", provider)
	}
}

func TestLoadDefaultProviderNameIsDeterministic(t *testing.T) {
	dir := t.TempDir()
	t.Setenv("AGENTU_TEST_KEY", "sk-test")
	path := filepath.Join(dir, "agentu.yaml")
	if err := os.WriteFile(path, []byte(`
providers:
  two:
    base_url: https://two.example.com
    api_key: ${AGENTU_TEST_KEY}
    models:
      - id: model-b
  one:
    base_url: https://one.example.com
    api_key: ${AGENTU_TEST_KEY}
    models:
      - id: model-a
`), 0o644); err != nil {
		t.Fatal(err)
	}

	cfg, err := Load(path)
	if err != nil {
		t.Fatal(err)
	}
	if got := cfg.DefaultProviderName(); got != "one" {
		t.Fatalf("default provider = %q", got)
	}
}

func TestLoadRejectsInvalidThinking(t *testing.T) {
	dir := t.TempDir()
	t.Setenv("AGENTU_TEST_KEY", "sk-test")
	path := filepath.Join(dir, "agentu.yaml")
	if err := os.WriteFile(path, []byte(`
providers:
  test:
    base_url: https://example.com
    api_key: ${AGENTU_TEST_KEY}
    models:
      - id: test-model
        thinking: huge
`), 0o644); err != nil {
		t.Fatal(err)
	}

	_, err := Load(path)
	if err == nil || !strings.Contains(err.Error(), "thinking") {
		t.Fatalf("err = %v", err)
	}
}

func TestLoadRequiresProviderFields(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "agentu.yaml")
	if err := os.WriteFile(path, []byte(`
providers:
  test:
    base_url: https://example.com
`), 0o644); err != nil {
		t.Fatal(err)
	}

	_, err := Load(path)
	if err == nil {
		t.Fatal("expected error")
	}
}

func TestLoadRejectsLegacyProviderConfig(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "agentu.yaml")
	if err := os.WriteFile(path, []byte(`
provider:
  base_url: https://example.com
  api_key: sk-test
  models:
    - id: test-model
`), 0o644); err != nil {
		t.Fatal(err)
	}

	_, err := Load(path)
	if err == nil || !strings.Contains(err.Error(), "field provider not found") {
		t.Fatalf("err = %v", err)
	}
}

func TestLoadRejectsActiveProviderConfig(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "agentu.yaml")
	if err := os.WriteFile(path, []byte(`
active_provider: loveuer
providers:
  loveuer:
    base_url: https://example.com
    api_key: sk-test
    models:
      - id: test-model
`), 0o644); err != nil {
		t.Fatal(err)
	}

	_, err := Load(path)
	if err == nil || !strings.Contains(err.Error(), "field active_provider not found") {
		t.Fatalf("err = %v", err)
	}
}