package config

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

// Test: LoadState loads valid state
func TestLoadState(t *testing.T) {
	tests := []struct {
		name      string
		stateYAML string
		verify    func(t *testing.T, config *State)
		wantErr   bool
	}{
		{
			name: "loads complete state",
			stateYAML: `operator:
  email: "admin@example.com"
cloud:
  central:
    domain: "central.example.com"
`,
			verify: func(t *testing.T, config *State) {
				if config.Operator.Email != "admin@example.com" {
					t.Error("operator email not loaded correctly")
				}
				if config.Cloud.Central.Domain != "central.example.com" {
					t.Error("central domain not loaded correctly")
				}
			},
			wantErr: false,
		},
		{
			name: "loads minimal state",
			stateYAML: `operator:
  email: "admin@example.com"
`,
			verify: func(t *testing.T, config *State) {
				if config.Operator.Email != "admin@example.com" {
					t.Error("operator email not loaded correctly")
				}
			},
			wantErr: false,
		},
		{
			name:      "loads empty state",
			stateYAML: "{}\n",
			verify: func(t *testing.T, config *State) {
				if config.Operator.Email != "" {
					t.Error("expected empty operator email")
				}
			},
			wantErr: false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			tempDir := t.TempDir()
			statePath := filepath.Join(tempDir, "state.yaml")

			if err := os.WriteFile(statePath, []byte(tt.stateYAML), 0644); err != nil {
				t.Fatalf("setup failed: %v", err)
			}

			config, err := LoadState(statePath)
			if tt.wantErr {
				if err == nil {
					t.Error("expected error, got nil")
				}
				return
			}

			if err != nil {
				t.Errorf("unexpected error: %v", err)
				return
			}

			if config == nil {
				t.Fatal("config is nil")
			}

			if tt.verify != nil {
				tt.verify(t, config)
			}
		})
	}
}

// Test: LoadState error cases
func TestLoadState_Errors(t *testing.T) {
	tests := []struct {
		name        string
		setupFunc   func(t *testing.T) string
		errContains string
	}{
		{
			name: "non-existent file",
			setupFunc: func(t *testing.T) string {
				return filepath.Join(t.TempDir(), "nonexistent.yaml")
			},
			errContains: "reading config file",
		},
		{
			name: "invalid yaml",
			setupFunc: func(t *testing.T) string {
				tempDir := t.TempDir()
				statePath := filepath.Join(tempDir, "state.yaml")
				content := `invalid: yaml: [[[`
				if err := os.WriteFile(statePath, []byte(content), 0644); err != nil {
					t.Fatalf("setup failed: %v", err)
				}
				return statePath
			},
			errContains: "parsing config file",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			statePath := tt.setupFunc(t)
			_, err := LoadState(statePath)

			if err == nil {
				t.Error("expected error, got nil")
			} else if !strings.Contains(err.Error(), tt.errContains) {
				t.Errorf("error %q does not contain %q", err.Error(), tt.errContains)
			}
		})
	}
}

// Test: SaveState saves state correctly
func TestSaveState(t *testing.T) {
	tests := []struct {
		name   string
		config *State
		verify func(t *testing.T, statePath string)
	}{
		{
			name: "saves complete state",
			config: func() *State {
				cfg := &State{}
				cfg.Operator.Email = "admin@example.com"
				cfg.Cloud.Central.Domain = "central.example.com"
				return cfg
			}(),
			verify: func(t *testing.T, statePath string) {
				content, err := os.ReadFile(statePath)
				if err != nil {
					t.Fatalf("failed to read saved state: %v", err)
				}
				contentStr := string(content)
				if !strings.Contains(contentStr, "admin@example.com") {
					t.Error("saved state missing operator email")
				}
				if !strings.Contains(contentStr, "central.example.com") {
					t.Error("saved state missing central domain")
				}
			},
		},
		{
			name:   "saves empty state",
			config: &State{},
			verify: func(t *testing.T, statePath string) {
				if _, err := os.Stat(statePath); os.IsNotExist(err) {
					t.Error("state file not created")
				}
			},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			tempDir := t.TempDir()
			statePath := filepath.Join(tempDir, "subdir", "state.yaml")

			err := SaveState(tt.config, statePath)
			if err != nil {
				t.Errorf("SaveState failed: %v", err)
				return
			}

			// Verify file exists
			if _, err := os.Stat(statePath); err != nil {
				t.Errorf("state file not created: %v", err)
				return
			}

			// Verify file permissions
			info, err := os.Stat(statePath)
			if err != nil {
				t.Fatalf("failed to stat state file: %v", err)
			}
			if info.Mode().Perm() != 0644 {
				t.Errorf("expected permissions 0644, got %v", info.Mode().Perm())
			}

			// Verify content can be loaded back
			loadedConfig, err := LoadState(statePath)
			if err != nil {
				t.Errorf("failed to reload saved state: %v", err)
			} else if loadedConfig == nil {
				t.Error("loaded config is nil")
			}

			if tt.verify != nil {
				tt.verify(t, statePath)
			}
		})
	}
}

// Test: SaveState creates directory
func TestSaveState_CreatesDirectory(t *testing.T) {
	tempDir := t.TempDir()
	statePath := filepath.Join(tempDir, "nested", "dirs", "state.yaml")

	config := &State{}
	err := SaveState(config, statePath)
	if err != nil {
		t.Fatalf("SaveState failed: %v", err)
	}

	// Verify nested directories were created
	if _, err := os.Stat(filepath.Dir(statePath)); err != nil {
		t.Errorf("directory not created: %v", err)
	}

	// Verify file exists
	if _, err := os.Stat(statePath); err != nil {
		t.Errorf("state file not created: %v", err)
	}
}

// Test: State.IsEmpty checks if config is empty
func TestState_IsEmpty(t *testing.T) {
	tests := []struct {
		name   string
		config *State
		want   bool
	}{
		{
			name:   "nil config is empty",
			config: nil,
			want:   true,
		},
		{
			name:   "default config is empty",
			config: &State{},
			want:   true,
		},
		{
			name: "config with only central domain is not empty",
			config: func() *State {
				cfg := &State{}
				cfg.Cloud.Central.Domain = "central.example.com"
				return cfg
			}(),
			want: false,
		},
		{
			name: "config with only operator email is not empty",
			config: func() *State {
				cfg := &State{}
				cfg.Operator.Email = "admin@example.com"
				return cfg
			}(),
			want: false,
		},
		{
			name: "config with all fields is not empty",
			config: func() *State {
				cfg := &State{}
				cfg.Cloud.Central.Domain = "central.example.com"
				cfg.Operator.Email = "admin@example.com"
				return cfg
			}(),
			want: false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := tt.config.IsEmpty()
			if got != tt.want {
				t.Errorf("IsEmpty() = %v, want %v", got, tt.want)
			}
		})
	}
}

// Test: Round-trip save and load preserves data
func TestState_RoundTrip(t *testing.T) {
	tempDir := t.TempDir()
	statePath := filepath.Join(tempDir, "state.yaml")

	// Create config with all fields
	original := &State{}
	original.Operator.Email = "admin@example.com"
	original.Cloud.Central.Domain = "central.example.com"

	// Save
	if err := SaveState(original, statePath); err != nil {
		t.Fatalf("SaveState failed: %v", err)
	}

	// Load
	loaded, err := LoadState(statePath)
	if err != nil {
		t.Fatalf("LoadState failed: %v", err)
	}

	// Verify all fields match
	if loaded.Operator.Email != original.Operator.Email {
		t.Errorf("email mismatch: got %q, want %q", loaded.Operator.Email, original.Operator.Email)
	}
	if loaded.Cloud.Central.Domain != original.Cloud.Central.Domain {
		t.Errorf("central domain mismatch: got %q, want %q", loaded.Cloud.Central.Domain, original.Cloud.Central.Domain)
	}
}