package review

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

func TestLoadBuiltinPersona(t *testing.T) {
	tests := []struct {
		name        string
		personaName string
		wantErr     bool
		wantDisplay string
	}{
		{
			name:        "security persona",
			personaName: "security",
			wantErr:     false,
			wantDisplay: "Security Specialist",
		},
		{
			name:        "architect persona",
			personaName: "architect",
			wantErr:     false,
			wantDisplay: "Software Architect",
		},
		{
			name:        "docs persona",
			personaName: "docs",
			wantErr:     false,
			wantDisplay: "Documentation Reviewer",
		},
		{
			name:        "unknown persona",
			personaName: "nonexistent",
			wantErr:     true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			p, err := LoadBuiltinPersona(tt.personaName)
			if tt.wantErr {
				if err == nil {
					t.Error("expected error, got nil")
				}
				return
			}
			if err != nil {
				t.Fatalf("unexpected error: %v", err)
			}
			if p.Name != tt.personaName {
				t.Errorf("Name = %q, want %q", p.Name, tt.personaName)
			}
			if p.DisplayName != tt.wantDisplay {
				t.Errorf("DisplayName = %q, want %q", p.DisplayName, tt.wantDisplay)
			}
			if p.Identity == "" {
				t.Error("Identity should not be empty")
			}
			if len(p.Focus) == 0 {
				t.Error("Focus should not be empty")
			}
		})
	}
}

func TestListBuiltinPersonas(t *testing.T) {
	names := ListBuiltinPersonas()
	if len(names) == 0 {
		t.Fatal("expected at least one built-in persona")
	}

	// Check for expected personas
	expected := map[string]bool{"security": false, "architect": false, "docs": false}
	for _, name := range names {
		if _, ok := expected[name]; ok {
			expected[name] = true
		}
	}
	for name, found := range expected {
		if !found {
			t.Errorf("expected built-in persona %q not found", name)
		}
	}
}

func TestLoadPersonaFromYAMLFile(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "test.yaml")

	content := `# Test persona
name: test
display_name: Test Persona
identity: |
  You are a test persona.
  Multi-line identity works.
focus:
  - testing
  - validation
ignore:
  - nothing
severity:
  major: Big problems
  minor: Small problems
  nit: Tiny problems
`

	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
		t.Fatalf("failed to write test file: %v", err)
	}

	p, err := LoadPersona(path)
	if err != nil {
		t.Fatalf("LoadPersona failed: %v", err)
	}

	if p.Name != "test" {
		t.Errorf("Name = %q, want %q", p.Name, "test")
	}
	if p.DisplayName != "Test Persona" {
		t.Errorf("DisplayName = %q, want %q", p.DisplayName, "Test Persona")
	}
	if len(p.Focus) != 2 {
		t.Errorf("Focus len = %d, want 2", len(p.Focus))
	}
	if !strings.Contains(p.Identity, "Multi-line") {
		t.Error("Identity should contain multi-line content")
	}
}

func TestLoadPersonaFromYMLFile(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "test.yml")

	content := `name: test
display_name: Test YML
identity: Test identity
focus:
  - testing
ignore: []
severity:
  major: Big
  minor: Small
  nit: Tiny
`

	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
		t.Fatalf("failed to write test file: %v", err)
	}

	p, err := LoadPersona(path)
	if err != nil {
		t.Fatalf("LoadPersona failed: %v", err)
	}

	if p.Name != "test" {
		t.Errorf("Name = %q, want %q", p.Name, "test")
	}
	if p.DisplayName != "Test YML" {
		t.Errorf("DisplayName = %q, want %q", p.DisplayName, "Test YML")
	}
}

func TestLoadPersonaFromJSONFile(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "test.json")

	content := `{
		"name": "test",
		"display_name": "Test Persona",
		"identity": "You are a test persona.\nMulti-line identity works.",
		"focus": ["testing", "validation"],
		"ignore": ["nothing"],
		"severity": {
			"major": "Big problems",
			"minor": "Small problems",
			"nit": "Tiny problems"
		}
	}`

	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
		t.Fatalf("failed to write test file: %v", err)
	}

	p, err := LoadPersona(path)
	if err != nil {
		t.Fatalf("LoadPersona failed: %v", err)
	}

	if p.Name != "test" {
		t.Errorf("Name = %q, want %q", p.Name, "test")
	}
	if p.DisplayName != "Test Persona" {
		t.Errorf("DisplayName = %q, want %q", p.DisplayName, "Test Persona")
	}
	if len(p.Focus) != 2 {
		t.Errorf("Focus len = %d, want 2", len(p.Focus))
	}
	if !strings.Contains(p.Identity, "Multi-line") {
		t.Error("Identity should contain multi-line content")
	}
}

func TestLoadPersonaValidation(t *testing.T) {
	tests := []struct {
		name    string
		content string
		ext     string
		wantErr string
	}{
		{
			name:    "missing name yaml",
			content: "identity: test\n",
			ext:     ".yaml",
			wantErr: "name is required",
		},
		{
			name:    "missing identity yaml",
			content: "name: test\n",
			ext:     ".yaml",
			wantErr: "identity is required",
		},
		{
			name:    "missing name json",
			content: `{"identity": "test"}`,
			ext:     ".json",
			wantErr: "name is required",
		},
		{
			name:    "missing identity json",
			content: `{"name": "test"}`,
			ext:     ".json",
			wantErr: "identity is required",
		},
		{
			name:    "display_name defaults to name",
			content: "name: test\nidentity: test identity\n",
			ext:     ".yaml",
			// No error expected - should succeed
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			dir := t.TempDir()
			path := filepath.Join(dir, "test"+tt.ext)
			if err := os.WriteFile(path, []byte(tt.content), 0644); err != nil {
				t.Fatalf("failed to write test file: %v", err)
			}

			p, err := LoadPersona(path)
			if tt.wantErr != "" {
				if err == nil {
					t.Errorf("expected error containing %q, got nil", tt.wantErr)
					return
				}
				if !strings.Contains(err.Error(), tt.wantErr) {
					t.Errorf("error = %q, want containing %q", err.Error(), tt.wantErr)
				}
				return
			}
			if err != nil {
				t.Fatalf("unexpected error: %v", err)
			}
			// Check display_name defaulting
			if p.DisplayName == "" {
				t.Error("DisplayName should default to Name")
			}
			if p.DisplayName != p.Name {
				t.Errorf("DisplayName should default to Name, got %q", p.DisplayName)
			}
		})
	}
}

func TestLoadPersonaFileNotFound(t *testing.T) {
	_, err := LoadPersona("/nonexistent/path/persona.yaml")
	if err == nil {
		t.Error("expected error for nonexistent file")
	}
}

func TestLoadPersonaInvalidYAML(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "invalid.yaml")
	if err := os.WriteFile(path, []byte("not valid yaml:\n  - [broken"), 0644); err != nil {
		t.Fatalf("failed to write test file: %v", err)
	}

	_, err := LoadPersona(path)
	if err == nil {
		t.Error("expected error for invalid YAML")
	}
}

func TestLoadPersonaInvalidJSON(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "invalid.json")
	if err := os.WriteFile(path, []byte("not valid json {"), 0644); err != nil {
		t.Fatalf("failed to write test file: %v", err)
	}

	_, err := LoadPersona(path)
	if err == nil {
		t.Error("expected error for invalid JSON")
	}
}

func TestLoadPersonaCaseInsensitiveExtension(t *testing.T) {
	tests := []struct {
		name string
		ext  string
	}{
		{"lowercase yaml", ".yaml"},
		{"uppercase YAML", ".YAML"},
		{"mixed case Yaml", ".Yaml"},
		{"lowercase yml", ".yml"},
		{"uppercase YML", ".YML"},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			dir := t.TempDir()
			path := filepath.Join(dir, "test"+tt.ext)
			content := "name: test\nidentity: test identity\n"
			if err := os.WriteFile(path, []byte(content), 0644); err != nil {
				t.Fatalf("failed to write test file: %v", err)
			}

			p, err := LoadPersona(path)
			if err != nil {
				t.Fatalf("LoadPersona failed for extension %s: %v", tt.ext, err)
			}
			if p.Name != "test" {
				t.Errorf("Name = %q, want %q", p.Name, "test")
			}
		})
	}
}

func TestCapitalizeFirst(t *testing.T) {
	tests := []struct {
		input string
		want  string
	}{
		{"hello", "Hello"},
		{"Hello", "Hello"},
		{"HELLO", "HELLO"},
		{"a", "A"},
		{"", ""},
		{"日本語", "日本語"}, // Non-ASCII: Japanese doesn't have case
		{"über", "Über"},   // German umlaut
		{"élève", "Élève"}, // French accent
	}

	for _, tt := range tests {
		t.Run(tt.input, func(t *testing.T) {
			got := CapitalizeFirst(tt.input)
			if got != tt.want {
				t.Errorf("CapitalizeFirst(%q) = %q, want %q", tt.input, got, tt.want)
			}
		})
	}
}

func TestListBuiltinPersonasReturnsEmptySlice(t *testing.T) {
	// ListBuiltinPersonas should return an empty slice (not nil) on error.
	// We can't easily test the error case, but we can verify the success case
	// returns a proper slice.
	names := ListBuiltinPersonas()
	if names == nil {
		t.Error("ListBuiltinPersonas should return empty slice, not nil")
	}
}

func TestYAMLMultilineStrings(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "multiline.yaml")

	// Test literal block scalar (|) which preserves newlines
	content := `name: multiline
display_name: Multiline Test
identity: |
  First line.
  Second line.
  Third line.
focus:
  - item one
ignore: []
severity:
  major: Major issue
  minor: Minor issue
  nit: Nit
`

	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
		t.Fatalf("failed to write test file: %v", err)
	}

	p, err := LoadPersona(path)
	if err != nil {
		t.Fatalf("LoadPersona failed: %v", err)
	}

	// Literal block scalar preserves newlines
	if !strings.Contains(p.Identity, "\n") {
		t.Error("Identity should contain newlines from literal block scalar")
	}
	if !strings.Contains(p.Identity, "Second line") {
		t.Error("Identity should contain 'Second line'")
	}
}

func TestYAMLComments(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "comments.yaml")

	content := `# This is a comment
name: commented  # inline comment
display_name: Commented Persona
# Another comment
identity: Test identity
focus:
  - item  # comment after item
ignore: []
severity:
  major: Major
  minor: Minor
  nit: Nit
`

	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
		t.Fatalf("failed to write test file: %v", err)
	}

	p, err := LoadPersona(path)
	if err != nil {
		t.Fatalf("LoadPersona failed: %v", err)
	}

	// Comments should be ignored
	if p.Name != "commented" {
		t.Errorf("Name = %q, want %q", p.Name, "commented")
	}
	if p.Focus[0] != "item" {
		t.Errorf("Focus[0] = %q, want %q", p.Focus[0], "item")
	}
}