package processor

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

	"github.com/stretchr/testify/assert"
)

func TestLoadExternalLuaFile(t *testing.T) {
	tmpDir, err := os.MkdirTemp("", "lua-external-test-*")
	assert.NoError(t, err)
	defer os.RemoveAll(tmpDir)

	// Create a test Lua file
	luaFile := filepath.Join(tmpDir, "test.lua")
	luaContent := `data.value = 42
modified = true`
	err = os.WriteFile(luaFile, []byte(luaContent), 0644)
	assert.NoError(t, err)

	tests := []struct {
		name      string
		luaPath   string
		sourceDir string
		expected  string
		wantError bool
	}{
		{
			name:      "Relative path with sourceDir",
			luaPath:   "test.lua",
			sourceDir: tmpDir,
			expected:  luaContent,
			wantError: false,
		},
		{
			name:      "Absolute path",
			luaPath:   luaFile,
			sourceDir: "",
			expected:  luaContent,
			wantError: false,
		},
		{
			name:      "Relative path without sourceDir (uses CWD)",
			luaPath:   filepath.Base(luaFile),
			sourceDir: "",
			expected:  luaContent,
			wantError: false,
		},
		{
			name:      "Nested relative path",
			luaPath:   "scripts/test.lua",
			sourceDir: tmpDir,
			expected:  "",
			wantError: true,
		},
		{
			name:      "Non-existent file",
			luaPath:   "nonexistent.lua",
			sourceDir: tmpDir,
			expected:  "",
			wantError: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			// Change to tmpDir for CWD-based tests
			if tt.sourceDir == "" && !filepath.IsAbs(tt.luaPath) {
				origDir, _ := os.Getwd()
				defer os.Chdir(origDir)
				os.Chdir(tmpDir)
			}

			result, err := LoadExternalLuaFile(tt.luaPath, tt.sourceDir)
			if tt.wantError {
				assert.Error(t, err)
				assert.Empty(t, result)
			} else {
				assert.NoError(t, err)
				assert.Equal(t, tt.expected, result)
			}
		})
	}
}

func TestBuildLuaScriptWithExternalFile(t *testing.T) {
	tmpDir, err := os.MkdirTemp("", "lua-external-build-test-*")
	assert.NoError(t, err)
	defer os.RemoveAll(tmpDir)

	// Create a test Lua file
	luaFile := filepath.Join(tmpDir, "multiply.lua")
	luaContent := `v1 = v1 * 2`
	err = os.WriteFile(luaFile, []byte(luaContent), 0644)
	assert.NoError(t, err)

	// Test with relative path
	relativePath := filepath.Base(luaFile)
	result := BuildLuaScript("@"+relativePath, tmpDir)
	assert.Contains(t, result, "v1 = v1 * 2")
	assert.Contains(t, result, "function run()")

	// Test with absolute path
	result = BuildLuaScript("@"+luaFile, "")
	assert.Contains(t, result, "v1 = v1 * 2")
}

func TestBuildLuaScriptWithExternalFileError(t *testing.T) {
	// Test that missing file returns error script
	result := BuildLuaScript("@nonexistent.lua", "/tmp")
	assert.Contains(t, result, "error(")
	assert.Contains(t, result, "Failed to load external Lua file")
}

func TestBuildJSONLuaScriptWithExternalFile(t *testing.T) {
	tmpDir, err := os.MkdirTemp("", "lua-external-json-test-*")
	assert.NoError(t, err)
	defer os.RemoveAll(tmpDir)

	// Create a test Lua file
	luaFile := filepath.Join(tmpDir, "json_modify.lua")
	luaContent := `data.value = 84
modified = true`
	err = os.WriteFile(luaFile, []byte(luaContent), 0644)
	assert.NoError(t, err)

	// Test with relative path
	relativePath := filepath.Base(luaFile)
	result := BuildJSONLuaScript("@"+relativePath, tmpDir)
	assert.Contains(t, result, "data.value = 84")
	assert.Contains(t, result, "modified = true")
	assert.Contains(t, result, "function run()")
}

func TestBuildLuaScriptWithInlineCode(t *testing.T) {
	// Test that inline code (without @) still works
	result := BuildLuaScript("v1 = v1 * 2", "")
	assert.Contains(t, result, "v1 = v1 * 2")
	assert.Contains(t, result, "function run()")
	assert.NotContains(t, result, "@")
}

func TestBuildLuaScriptExternalFileWithVariables(t *testing.T) {
	tmpDir, err := os.MkdirTemp("", "lua-external-vars-test-*")
	assert.NoError(t, err)
	defer os.RemoveAll(tmpDir)

	// Create a test Lua file with variable reference
	luaFile := filepath.Join(tmpDir, "with_vars.lua")
	luaContent := `v1 = v1 * $multiply`
	err = os.WriteFile(luaFile, []byte(luaContent), 0644)
	assert.NoError(t, err)

	// Set a global variable
	SetVariables(map[string]interface{}{"multiply": 1.5})
	defer SetVariables(map[string]interface{}{})

	// Test that variables are substituted in external files
	result := BuildLuaScript("@"+filepath.Base(luaFile), tmpDir)
	assert.Contains(t, result, "v1 = v1 * 1.5")
	assert.NotContains(t, result, "$multiply")
}

func TestBuildLuaScriptExternalFileNestedPath(t *testing.T) {
	tmpDir, err := os.MkdirTemp("", "lua-external-nested-test-*")
	assert.NoError(t, err)
	defer os.RemoveAll(tmpDir)

	// Create nested directory structure
	scriptsDir := filepath.Join(tmpDir, "scripts")
	err = os.MkdirAll(scriptsDir, 0755)
	assert.NoError(t, err)

	luaFile := filepath.Join(scriptsDir, "test.lua")
	luaContent := `data.value = 100`
	err = os.WriteFile(luaFile, []byte(luaContent), 0644)
	assert.NoError(t, err)

	// Test with nested relative path
	result := BuildLuaScript("@scripts/test.lua", tmpDir)
	assert.Contains(t, result, "data.value = 100")
}

func TestBuildLuaScriptExternalFileWithPrependLuaAssignment(t *testing.T) {
	tmpDir, err := os.MkdirTemp("", "lua-external-prepend-test-*")
	assert.NoError(t, err)
	defer os.RemoveAll(tmpDir)

	// Create a test Lua file with operator prefix (should trigger prepend)
	luaFile := filepath.Join(tmpDir, "multiply.lua")
	luaContent := `* 2`
	err = os.WriteFile(luaFile, []byte(luaContent), 0644)
	assert.NoError(t, err)

	// Test that prepend still works with external files
	result := BuildLuaScript("@"+filepath.Base(luaFile), tmpDir)
	// PrependLuaAssignment adds "v1 = v1" + "* 2" = "v1 = v1* 2" (no space between v1 and *)
	assert.Contains(t, result, "v1 = v1* 2")
}

func TestBuildLuaScriptExternalFilePreservesWhitespace(t *testing.T) {
	tmpDir, err := os.MkdirTemp("", "lua-external-whitespace-test-*")
	assert.NoError(t, err)
	defer os.RemoveAll(tmpDir)

	// Create a test Lua file with multiline content
	luaFile := filepath.Join(tmpDir, "multiline.lua")
	luaContent := `if data.items then
    for i, item in ipairs(data.items) do
        item.value = item.value * 2
    end
    modified = true
end`
	err = os.WriteFile(luaFile, []byte(luaContent), 0644)
	assert.NoError(t, err)

	// Test that whitespace and formatting is preserved
	result := BuildLuaScript("@"+filepath.Base(luaFile), tmpDir)
	assert.Contains(t, result, "if data.items then")
	assert.Contains(t, result, "    for i, item in ipairs(data.items) do")
	assert.Contains(t, result, "        item.value = item.value * 2")
}