package config

import (
	"errors"
	"fmt"

	luajit "git.sharkk.net/Sky/LuaJIT-to-Go"
)

// Config represents a configuration loaded from a Lua file
type Config struct {
	values map[string]any
}

// New creates a new empty configuration
func New() *Config {
	return &Config{
		values: make(map[string]any),
	}
}

// Load loads configuration from a Lua file
func Load(filePath string) (*Config, error) {
	// Create a new Lua state
	state := luajit.New()
	if state == nil {
		return nil, errors.New("failed to create Lua state")
	}
	defer state.Close()

	// Execute the Lua file
	if err := state.DoFile(filePath); err != nil {
		return nil, fmt.Errorf("failed to load config file: %w", err)
	}

	// Create the config instance
	config := New()

	// Extract values from the Lua state
	if err := extractGlobals(state, config.values); err != nil {
		return nil, err
	}

	return config, nil
}

// extractGlobals extracts global variables from the Lua state
func extractGlobals(state *luajit.State, values map[string]any) error {
	// Get the globals table (_G)
	state.GetGlobal("_G")
	if !state.IsTable(-1) {
		state.Pop(1)
		return errors.New("failed to get globals table")
	}

	// Pre-populate with standard globals for reference checking
	stdGlobals := map[string]bool{
		"_G": true, "_VERSION": true, "assert": true, "collectgarbage": true,
		"coroutine": true, "debug": true, "dofile": true, "error": true,
		"getmetatable": true, "io": true, "ipairs": true, "load": true,
		"loadfile": true, "loadstring": true, "math": true, "next": true,
		"os": true, "package": true, "pairs": true, "pcall": true,
		"print": true, "rawequal": true, "rawget": true, "rawset": true,
		"require": true, "select": true, "setmetatable": true, "string": true,
		"table": true, "tonumber": true, "tostring": true, "type": true,
		"unpack": true, "xpcall": true,
		// LuaJIT specific globals
		"jit": true, "bit": true, "ffi": true, "bit32": true,
	}

	// First, let's get the original globals to compare with user globals
	originalGlobals := make(map[string]bool)

	// Execute empty Lua state to get standard globals
	emptyState := luajit.New()
	if emptyState != nil {
		defer emptyState.Close()

		emptyState.GetGlobal("_G")
		emptyState.PushNil() // Start iteration
		for emptyState.Next(-2) {
			if emptyState.IsString(-2) {
				key := emptyState.ToString(-2)
				originalGlobals[key] = true
			}
			emptyState.Pop(1) // Pop value, leave key for next iteration
		}
		emptyState.Pop(1) // Pop _G
	}

	// Iterate through the globals table
	state.PushNil() // Start iteration
	for state.Next(-2) {
		// Stack now has key at -2 and value at -1

		// Get key as string
		if !state.IsString(-2) {
			state.Pop(1) // Pop value, leave key for next iteration
			continue
		}

		key := state.ToString(-2)

		// Skip standard Lua globals, but only if they're not overridden by user
		// (standard globals will be functions or tables, user values usually aren't)
		valueType := state.GetType(-1)

		// Skip functions, userdata, and threads regardless of origin
		if valueType == luajit.TypeFunction || valueType == luajit.TypeUserData || valueType == luajit.TypeThread {
			state.Pop(1)
			continue
		}

		// For known Lua globals, we need to see if they're the original or user-defined
		if stdGlobals[key] {
			// For simple value types, assume user-defined
			if valueType == luajit.TypeBoolean || valueType == luajit.TypeNumber || valueType == luajit.TypeString {
				// These are probably user values with standard names
			} else if originalGlobals[key] {
				// If it's in the original globals and not a simple type, skip it
				state.Pop(1)
				continue
			}
		}

		// Handle primitive types directly
		switch valueType {
		case luajit.TypeBoolean:
			values[key] = state.ToBoolean(-1)
			state.Pop(1)
			continue
		case luajit.TypeNumber:
			values[key] = state.ToNumber(-1)
			state.Pop(1)
			continue
		case luajit.TypeString:
			values[key] = state.ToString(-1)
			state.Pop(1)
			continue
		case luajit.TypeTable:
			// For tables, use the existing conversion logic
		default:
			// Skip unsupported types
			state.Pop(1)
			continue
		}

		// Handle tables (arrays and maps)
		if valueType == luajit.TypeTable {
			// Check if it looks like an array first
			arrLen := state.GetTableLength(-1)
			if arrLen > 0 {
				// Process as array
				arr := make([]any, arrLen)
				for i := 1; i <= arrLen; i++ {
					state.PushNumber(float64(i))
					state.GetTable(-2) // Get t[i]

					switch state.GetType(-1) {
					case luajit.TypeBoolean:
						arr[i-1] = state.ToBoolean(-1)
					case luajit.TypeNumber:
						arr[i-1] = state.ToNumber(-1)
					case luajit.TypeString:
						arr[i-1] = state.ToString(-1)
					default:
						// For complex elements, try to convert
						if val, err := state.ToValue(-1); err == nil {
							arr[i-1] = val
						}
					}

					state.Pop(1) // Pop value
				}
				values[key] = arr
				state.Pop(1)
				continue
			}

			// Try normal table conversion for non-array tables
			if table, err := state.ToTable(-1); err == nil {
				values[key] = table
			}
		}

		// Pop value, leave key for next iteration
		state.Pop(1)
	}

	// Pop the globals table
	state.Pop(1)

	return nil
}

// Get returns a configuration value by key
func (c *Config) Get(key string) any {
	return c.values[key]
}

// GetString returns a string configuration value
func (c *Config) GetString(key string, defaultValue string) string {
	value, ok := c.values[key]
	if !ok {
		return defaultValue
	}

	str, ok := value.(string)
	if !ok {
		return defaultValue
	}

	return str
}

// GetInt returns an integer configuration value
func (c *Config) GetInt(key string, defaultValue int) int {
	value, ok := c.values[key]
	if !ok {
		return defaultValue
	}

	// Handle both int and float64 (which is what Lua numbers become in Go)
	switch v := value.(type) {
	case int:
		return v
	case float64:
		return int(v)
	default:
		return defaultValue
	}
}

// GetFloat returns a float configuration value
func (c *Config) GetFloat(key string, defaultValue float64) float64 {
	value, ok := c.values[key]
	if !ok {
		return defaultValue
	}

	// Handle both float64 and int
	switch v := value.(type) {
	case float64:
		return v
	case int:
		return float64(v)
	default:
		return defaultValue
	}
}

// GetBool returns a boolean configuration value
func (c *Config) GetBool(key string, defaultValue bool) bool {
	value, ok := c.values[key]
	if !ok {
		return defaultValue
	}

	boolValue, ok := value.(bool)
	if !ok {
		return defaultValue
	}

	return boolValue
}

// GetMap returns a map configuration value
func (c *Config) GetMap(key string) map[string]any {
	value, ok := c.values[key]
	if !ok {
		return nil
	}

	table, ok := value.(map[string]any)
	if !ok {
		return nil
	}

	return table
}

// GetArray returns an array of values from a Lua array
func (c *Config) GetArray(key string) []any {
	value := c.Get(key)
	if value == nil {
		return nil
	}

	// Direct array
	if arr, ok := value.([]any); ok {
		return arr
	}

	// Arrays in Lua might also be represented as maps with an empty string key
	valueMap, ok := value.(map[string]any)
	if !ok {
		return nil
	}

	// The array data is stored with an empty key
	arr, ok := valueMap[""]
	if !ok {
		return nil
	}

	// Check if it's a float64 array (common for Lua numeric arrays)
	if floatArr, ok := arr.([]float64); ok {
		// Convert to []any
		result := make([]any, len(floatArr))
		for i, v := range floatArr {
			result[i] = v
		}
		return result
	}

	// Otherwise, try to return as is
	anyArr, ok := arr.([]any)
	if !ok {
		return nil
	}

	return anyArr
}

// GetIntArray returns an array of integers from a Lua array
func (c *Config) GetIntArray(key string) []int {
	value := c.Get(key)
	if value == nil {
		return nil
	}

	// Direct array case
	if arr, ok := value.([]any); ok {
		result := make([]int, 0, len(arr))
		for _, v := range arr {
			if num, ok := v.(float64); ok {
				result = append(result, int(num))
			}
		}
		return result
	}

	// Arrays in Lua might also be represented as maps with an empty string key
	valueMap, ok := value.(map[string]any)
	if !ok {
		return nil
	}

	// The array data is stored with an empty key
	arr, ok := valueMap[""]
	if !ok {
		return nil
	}

	// For numeric arrays, LuaJIT returns []float64
	floatArr, ok := arr.([]float64)
	if !ok {
		return nil
	}

	// Convert to int slice
	result := make([]int, len(floatArr))
	for i, v := range floatArr {
		result[i] = int(v)
	}

	return result
}

// GetStringArray returns an array of strings from a Lua array
func (c *Config) GetStringArray(key string) []string {
	arr := c.GetArray(key)
	if arr == nil {
		return nil
	}

	result := make([]string, 0, len(arr))
	for _, v := range arr {
		if str, ok := v.(string); ok {
			result = append(result, str)
		}
	}

	return result
}

// Values returns all configuration values
// Note: The returned map should not be modified
func (c *Config) Values() map[string]any {
	return c.values
}

// Set sets a configuration value
func (c *Config) Set(key string, value any) {
	c.values[key] = value
}