package plugins

import (
	"fmt"

	lua "github.com/yuin/gopher-lua"
)

// pushError pushes an error message as a Lua error (using lua.Errorf-style).
// Returns 0 (no return values — the Lua function will error).
func pushError(L *lua.LState, err error) int {
	L.RaiseError("%s", err.Error())
	return 0 // unreachable, but satisfies signature
}

// pushResult pushes a single value to Lua stack and returns 1.
func pushResult(L *lua.LState, val lua.LValue) int {
	L.Push(val)
	return 1
}

// pushOK pushes true (success) to Lua stack.
func pushOK(L *lua.LState) int {
	L.Push(lua.LBool(true))
	return 1
}

// checkOptString gets an optional string argument at position.
func checkOptString(L *lua.LState, pos int, defaultVal string) string {
	if L.GetTop() >= pos {
		return L.CheckString(pos)
	}
	return defaultVal
}

// checkOptInt gets an optional int argument at position.
func checkOptInt(L *lua.LState, pos int, defaultVal int) int {
	if L.GetTop() >= pos {
		return L.CheckInt(pos)
	}
	return defaultVal
}

// checkOptTable gets an optional table argument at position.
func checkOptTable(L *lua.LState, pos int) *lua.LTable {
	if L.GetTop() >= pos && L.Get(pos).Type() == lua.LTTable {
		return L.CheckTable(pos)
	}
	return nil
}

// tableToMap converts a Lua table to map[string]interface{}.
// Only handles string keys and basic value types.
func tableToMap(tbl *lua.LTable) map[string]interface{} {
	m := make(map[string]interface{})
	tbl.ForEach(func(key lua.LValue, val lua.LValue) {
		k := lua.LVAsString(key)
		m[k] = luaValueToGo(val)
	})
	return m
}

// luaValueToGo converts a Lua value to a Go interface{}.
func luaValueToGo(v lua.LValue) interface{} {
	if v == lua.LNil {
		return nil
	}
	switch val := v.(type) {
	case lua.LBool:
		return bool(val)
	case lua.LString:
		return string(val)
	case lua.LNumber:
		return float64(val)
	case *lua.LTable:
		// Detect if it's an array or map
		if val.MaxN() > 0 {
			arr := make([]interface{}, 0, val.MaxN())
			for i := 1; i <= val.MaxN(); i++ {
				arr = append(arr, luaValueToGo(val.RawGetInt(i)))
			}
			return arr
		}
		// Check if table has any keys at all — empty tables are ambiguous.
		// DB queries return empty tables when no rows match; the frontend
		// expects a valid array [] (with .length), not {} (where .length is undefined).
		hasKeys := false
		val.ForEach(func(k lua.LValue, v lua.LValue) {
			hasKeys = true
		})
		if !hasKeys {
			return make([]interface{}, 0)
		}
		m := make(map[string]interface{})
		val.ForEach(func(k lua.LValue, v lua.LValue) {
			m[fmt.Sprintf("%v", k)] = luaValueToGo(v)
		})
		return m
	default:
		return fmt.Sprintf("%v", v)
	}
}