package naming

import (
	"testing"
)

func TestSingularize(t *testing.T) {
	tests := []struct {
		name     string
		input    string
		expected string
	}{
		// Regular plurals
		{"simple s", "users", "user"},
		{"simple s uppercase", "Users", "User"},
		{"tables", "tables", "table"},

		// ies -> y
		{"ies to y", "companies", "company"},
		{"ies to y uppercase", "Companies", "Company"},
		{"cities", "cities", "city"},
		{"categories", "categories", "category"},

		// ves -> f/fe
		{"ves to f", "halves", "half"},
		{"ves to fe - knife", "knives", "knife"},
		{"ves to fe - wife", "wives", "wife"},
		{"ves to fe - life", "lives", "life"},

		// es endings
		{"xes", "boxes", "box"},
		{"shes", "dishes", "dish"},
		{"ches", "watches", "watch"},
		{"ses", "classes", "class"},

		// oes -> o
		{"oes", "tomatoes", "tomato"},
		{"heroes", "heroes", "hero"},

		// Irregular plurals
		{"people", "people", "person"},
		{"children", "children", "child"},
		{"men", "men", "man"},
		{"women", "women", "woman"},
		{"teeth", "teeth", "tooth"},
		{"feet", "feet", "foot"},
		{"mice", "mice", "mouse"},
		{"geese", "geese", "goose"},

		// Unchanged
		{"sheep", "sheep", "sheep"},
		{"fish", "fish", "fish"},
		{"deer", "deer", "deer"},
		{"series", "series", "series"},
		{"species", "species", "species"},

		// Special cases
		{"data", "data", "datum"},
		{"analyses", "analyses", "analysis"},
		{"crises", "crises", "crisis"},

		// Edge cases
		{"empty", "", ""},
		{"already singular", "user", "user"},
		{"ss ending", "glass", "glass"},
	}

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

func TestPluralize(t *testing.T) {
	tests := []struct {
		name     string
		input    string
		expected string
	}{
		// Regular plurals
		{"simple", "user", "users"},
		{"simple uppercase", "User", "Users"},
		{"table", "table", "tables"},

		// y -> ies
		{"y to ies", "company", "companies"},
		{"y to ies uppercase", "Company", "Companies"},
		{"city", "city", "cities"},
		{"category", "category", "categories"},

		// consonant + y stays
		{"ay ending", "day", "days"},
		{"ey ending", "key", "keys"},
		{"oy ending", "boy", "boys"},

		// f/fe -> ves
		{"f to ves", "half", "halves"},
		{"fe to ves - knife", "knife", "knives"},
		{"fe to ves - wife", "wife", "wives"},
		{"fe to ves - life", "life", "lives"},

		// s, x, sh, ch -> es
		{"x to es", "box", "boxes"},
		{"sh to es", "dish", "dishes"},
		{"ch to es", "watch", "watches"},
		{"s to es", "class", "classes"},

		// o -> oes
		{"o to oes", "tomato", "tomatoes"},
		{"hero", "hero", "heroes"},

		// Irregular plurals
		{"person", "person", "people"},
		{"child", "child", "children"},
		{"man", "man", "men"},
		{"woman", "woman", "women"},
		{"tooth", "tooth", "teeth"},
		{"foot", "foot", "feet"},
		{"mouse", "mouse", "mice"},
		{"goose", "goose", "geese"},

		// Unchanged
		{"sheep", "sheep", "sheep"},
		{"fish", "fish", "fish"},
		{"deer", "deer", "deer"},
		{"series", "series", "series"},
		{"species", "species", "species"},

		// Edge cases
		{"empty", "", ""},
		{"already plural", "users", "users"},
	}

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

func TestSingularizeTableName(t *testing.T) {
	tests := []struct {
		name     string
		input    string
		expected string
	}{
		{"simple", "users", "user"},
		{"compound", "user_accounts", "user_account"},
		{"triple compound", "user_login_histories", "user_login_history"},
		{"already singular", "user", "user"},
		{"ies ending", "cashbag_conforms", "cashbag_conform"},
		{"complex table", "auth_user_groups", "auth_user_group"},
		{"empty", "", ""},
	}

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

func TestToPascalCase(t *testing.T) {
	tests := []struct {
		name     string
		input    string
		expected string
	}{
		{"simple", "user", "User"},
		{"snake_case", "user_account", "UserAccount"},
		{"triple", "user_login_history", "UserLoginHistory"},
		{"already pascal", "UserAccount", "UserAccount"},
		{"single char", "a", "A"},
		{"empty", "", ""},
		{"with numbers", "user_2fa", "User2fa"},
		{"multiple underscores", "user___account", "UserAccount"},
	}

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

func TestToSnakeCase(t *testing.T) {
	tests := []struct {
		name     string
		input    string
		expected string
	}{
		{"PascalCase", "UserAccount", "user_account"},
		{"simple", "User", "user"},
		{"multiple words", "UserLoginHistory", "user_login_history"},
		{"already snake", "user_account", "user_account"},
		{"empty", "", ""},
		{"single char", "A", "a"},
		{"with numbers", "User2FA", "user2_f_a"},
	}

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

// Benchmark tests
func BenchmarkSingularize(b *testing.B) {
	for i := 0; i < b.N; i++ {
		Singularize("companies")
	}
}

func BenchmarkPluralize(b *testing.B) {
	for i := 0; i < b.N; i++ {
		Pluralize("company")
	}
}

func BenchmarkToPascalCase(b *testing.B) {
	for i := 0; i < b.N; i++ {
		ToPascalCase("user_login_history")
	}
}

func BenchmarkToSnakeCase(b *testing.B) {
	for i := 0; i < b.N; i++ {
		ToSnakeCase("UserLoginHistory")
	}
}