// package main is the main package for the LapisDeploy program
package main

import (
	"errors"
	"log"

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

// Configuration stores information retrieved from a configuration file
type Configuration struct {
	port            int64
	sites_dir       string
	trusted_servers []string
	matrix          struct {
		homeserver string
		username   string
		password   string
		room_id    string
		disabled   bool
	}
}

// getStringFromTable retrieves a string from a table on the lua stack using the key passed in.
//
//	If the value is nil, 'out' is unchanged.
func getStringFromTable(L *lua.LState, lobj lua.LValue, key string, out *string) (bool, error) {
	lv := L.GetTable(lobj, lua.LString(key))
	if text, ok := lv.(lua.LString); ok { // Value is string
		*out = string(text)
	} else if _, ok := lv.(*lua.LNilType); !ok { // Value is not a string, and is not nil
		return true, errors.New("'" + key + "' is not a string")
	}
	return true, nil
}

// getIntFromTable retrieves an integer from a table on the Lua stack using the key passed in.
//
//	If the value is nil, 'out' is unchanged.
func getIntFromTable(L *lua.LState, lobj lua.LValue, key string, out *int64) (bool, error) {
	lv := L.GetTable(lobj, lua.LString(key))
	if int, ok := lv.(lua.LNumber); ok { // Value is number
		*out = int64(int)
	} else if _, ok := lv.(*lua.LNilType); !ok { // Value is not a number, and is not nil
		return true, errors.New("'" + key + "' is not a number")
	}
	return true, nil
}

// getBoolFromTable retrieves a bool from a table on the Lua stack using the key passed in.
//
//	If the value is nil, 'out' is unchanged.
func getBoolFromTable(L *lua.LState, lobj lua.LValue, key string, out *bool) (bool, error) {
	lv := L.GetTable(lobj, lua.LString(key))
	if boolean, ok := lv.(lua.LBool); ok { // Value is boolean
		*out = bool(boolean)
	} else if _, ok := lv.(*lua.LNilType); !ok { // Value is not a bool, and is not nil
		return true, errors.New("'" + key + "' is not a bool")
	}
	return true, nil
}

// getTableFromTable retrieves a nested table from the Lua stack using the key passed in.
func getTableFromTable(L *lua.LState, lobj lua.LValue, key string, out *lua.LValue) bool {
	lv := L.GetTable(lobj, lua.LString(key))
	*out = lv
	if _, ok := lv.(*lua.LNilType); ok {
		return false
	}
	return true
}

// parseConfig parses the JSON configuration file at 'path' and stores the contents in 'config'
func parseConfig(path string, config *Configuration) {
	log.Printf("Loading config from : %s ...", path)
	// Lua state setup
	L := lua.NewState()
	defer L.Close()

	L.DoFile(path)
	table := L.Get(-1)                    // Get the table returned by the config file
	if table.Type().String() != "table" { // Make sure value returned is of type 'table'
		log.Fatalf("config is of type : '%s', not 'table'", table.Type().String())
	}

	// Main config
	if _, err := getStringFromTable(L, table, "sites_dir", &config.sites_dir); err != nil {
		panic(err)
	}
	if _, err := getIntFromTable(L, table, "port", &config.port); err != nil {
		panic(err)
	}

	// Trusted servers
	var trusted_servers lua.LValue
	getTableFromTable(L, table, "trusted_servers", &trusted_servers) // Get the 'trusted_servers' table
	// Make sure 'config.trusted_servers' is of type 'table'
	if trusted_servers_type := trusted_servers.Type().String(); trusted_servers_type != "table" &&
		trusted_servers_type != "nil" {
		log.Fatalf("config.trusted_servers is of type : '%s', not 'table'", trusted_servers_type)
	} else if trusted_servers_type != "nil" { // If type is not nil (has to be table or it would've been caught already)
		for i := 1; i <= L.ObjLen(trusted_servers); i++ { // Loop through every trusted server
			lv := L.GetTable(trusted_servers, lua.LNumber(i))
			if text, ok := lv.(lua.LString); ok { // Value is string
				config.trusted_servers = append(config.trusted_servers, string(text))
			} else if _, ok := lv.(*lua.LNilType); !ok { // Value is not a string, and is not nil
				log.Fatalf("config.trusted_servers[%d] is of type : '%s', not 'string'", i, lv.Type().String())
			}
		}
	}

	// Matrix config
	var matrix lua.LValue
	getTableFromTable(L, table, "matrix", &matrix) // Get the 'matrix' table
	// Make sure 'config.matrix' is of type 'table'
	if matrix_type := matrix.Type().String(); matrix_type != "table" && matrix_type != "nil" {
		log.Fatalf("config.matrix is of type : '%s', not 'table'", matrix_type)
	} else if matrix_type != "nil" {
		if _, err := getBoolFromTable(L, matrix, "disabled", &config.matrix.disabled); err != nil {
			panic(err)
		}
		if !config.matrix.disabled { // Only load the rest of the matrix config if matrix isn't disabled
			if _, err := getStringFromTable(L, matrix, "homeserver", &config.matrix.homeserver); err != nil {
				panic(err)
			}
			if _, err := getStringFromTable(L, matrix, "username", &config.matrix.username); err != nil {
				panic(err)
			}
			if _, err := getStringFromTable(L, matrix, "password", &config.matrix.password); err != nil {
				panic(err)
			}
			if _, err := getStringFromTable(L, matrix, "room_id", &config.matrix.room_id); err != nil {
				panic(err)
			}
		}
	} else if matrix_type == "nil" { // Assume config.matrix.disabled is true if 'matrix' is missing from the config file
		config.matrix.disabled = true
	}
}