--[[
Implements some utilities for accounts in an smr-style database.

# Lists all author_id, author_name in the database
lua tools/accounts/main.lua ls 

# Resets the author 13 with a newly generated passfile, and writes the newly
# generated file to "new.passfile"
lua tools/accounts/main.lua -o new.passfile reset_password 13 

# Deletes the author with id 40, all posts and comments by this author will
# also be deleted.
lua tools/accounts/main.lua delete 40
]]
local function sha3(data)
	local tmpfn = os.tmpname()
	local tmpf = assert(io.open(tmpfn,"wb"))
	assert(tmpf:write(data))
	assert(tmpf:close())
	local pd = assert(io.popen("openssl dgst -sha3-512 " .. tmpfn, "r"))
	local hex = pd:read("*a")
	--[[
	hex looks like 
	SHA3-512(/tmp/lua_qQtQu4)= 9ece086e9bac491fac5c1d1046ca11d737b92a2b2ebd93f005d7b710110c0a678288166e7fbe796883a4f2e9b3ca9f484f521d0ce464345cc1aec96779149c14
	]]
	hex = hex:match("= (%x+)%s*$")
	assert(pd:close())
	local ret_data = {}
	for hex_byte in hex:gmatch("%x%x") do
		table.insert(ret_data,string.char(tonumber(hex_byte,16)))
	end
	return table.concat(ret_data)
end
local sql = require("lsqlite3")
local argparse = require("argparse")

local parser = argparse(){
	name = "tools/accounts/main.lua",
	description = "View, reset, and delete accounts",
	epilog = "Other tools included in the smr source distribution include:archive",
}
parser:help_max_width(80)
parser:option("-d --database","The database file","kore_chroot/data/posts.db")
parser:option("-o --output","Output to file (instead of stdout)")
local ls = parser:command("ls") {
	description = "lists all user_id's and user_names in the database"
}
local reset_password = parser:command("reset_password") {
	description = "Resets a password for a user, pass either an account id or an account name. If the inputed string can be converted to an account_id, and the account_id exists, it is considered an account_id, even if there is a user by the same name if it were considered an account_name."
}
reset_password:mutex(
	reset_password:argument("account_id_or_name","The accout id or account name to reset")
)
local delete = parser:command("delete") {
	description = "Deletes an account from the system. All posts and comments by this user are deleted as well. Once deleted, another user may claim the same username."
}
delete:mutex(
	delete:argument("account_id","The accout id to reset"),
	delete:argument("account_name","The name of the account to reset")
)


args = parser:parse()
local db,err,errmsg = sql.open(args.database, sql.OPEN_READWRITE)
if not db then
	error(string.format("Failed to open %s : %s",args.database,errmsg))
end
if args.output then
	io.stdout = assert(io.open(args.output,"w"))
end
if args.ls then
	for row in db:rows("SELECT id, name FROM authors;") do
		local id,name = unpack(row)
		io.stdout:write(string.format("%d\t%s\n",id,name))
	end
end
if args.reset_password then
	local rngf = assert(io.open("/dev/urandom","rb"))
	local passlength = string.byte(rngf:read(1)) + 64
	local salt = rngf:read(64)
	local password = rngf:read(passlength)
	local authorid, authorname
	authorid = tonumber(args.account_id_or_name)
	if authorid == nil then --could not be converted to a number
		authorname = args.account_id_or_name
	end
	rngf:close()

	assert(io.stdout:write(password))
	local hash = sha3(salt .. password)
	local stmt_update_pass
	if authorid then
		stmt_update_pass = db:prepare([[
			UPDATE authors
			SET
				salt = :salt,
				passhash = :hash
			WHERE
				id=:authorid;]]
		)
		stmt_update_pass:bind(3,authorid)
	else
		stmt_update_pass = db:prepare([[
			UPDATE authors
			SET
				salt = :salt,
				passhash = :hash
			WHERE
				name=:authorname;]]
		)
		stmt_update_pass:bind(3,authorname)
	end

	stmt_update_pass:bind_blob(1,salt)
	stmt_update_pass:bind_blob(2,hash)
	local err = stmt_update_pass:step()
	if err ~= sql.DONE then
		io.stderr:write(string.format("Failed %d:%s",err,db:errmsg()))
	end
end

db:close()
--[[
for k,v in pairs(args) do
	print(k,":",v)
end
]]