irc: persist per-target history to files; preload last lines on switch

Signed-off-by: Slendi <slendi@socopon.com>

main.lua

@@ -17,6 +17,7 @@ local socket = require("socket")
 local socketutil = require("socketutil")
 local _ = require("gettext")
 local T = require("ffi/util").template
+local lfs = require("libs/libkoreader-lfs")
 
 -- Chat view based on TextViewer for scrollable text & menu buttons
 local IrcChatView = TextViewer:extend{
@@ -38,6 +39,10 @@ local IrcChatView = TextViewer:extend{
     _current_target = nil,   -- active target ("*" for server console)
     _server_label = nil,
     _unread = nil,          -- map target => count of unseen messages
+    -- History persistence
+    _history_dir = nil,
+    _history_server_dir = nil,
+    _history_preload_lines = 500,
 }
 
 function IrcChatView:init()
@@ -64,6 +69,8 @@ function IrcChatView:init()
     self._current_target = nil
     self._server_label = self._server and (self._server.name or (self._server.host .. ":" .. tostring(self._server.port or 6667))) or "IRC"
     self._unread = {}
+    -- Init history before selecting initial buffer
+    self:initHistory()
     -- default to server console target
     self:switchTarget("*")
     self:updateTitle()
@@ -72,6 +79,75 @@ function IrcChatView:init()
     UIManager:nextTick(function() self:startConnection() end)
 end
 
+-- History helpers
+function IrcChatView:sanitizePathPart(part)
+    part = part or ""
+    part = part:gsub("[^%w%._%-#@]+", "_")
+    if part == "" then part = "_" end
+    return part
+end
+
+function IrcChatView:getServerId()
+    local name = self._server and (self._server.name or "") or ""
+    local host = self._server and (self._server.host or "") or ""
+    local port = self._server and tostring(self._server.port or 6667) or "6667"
+    local id = string.format("%s_%s_%s", name, host, port)
+    return self:sanitizePathPart(id)
+end
+
+function IrcChatView:initHistory()
+    self._history_dir = DataStorage:getDataDir() .. "/irc_logs"
+    lfs.mkdir(self._history_dir)
+    self._history_server_dir = self._history_dir .. "/" .. self:getServerId()
+    lfs.mkdir(self._history_server_dir)
+end
+
+function IrcChatView:getLogPath(target)
+    target = target or "*"
+    local fname = target == "*" and "console" or self:sanitizePathPart(target)
+    return string.format("%s/%s.log", self._history_server_dir, fname)
+end
+
+function IrcChatView:writeHistory(target, line)
+    local path = self:getLogPath(target)
+    local f = io.open(path, "a")
+    if f then
+        f:write(line, "\n")
+        f:close()
+    end
+end
+
+function IrcChatView:readLastLines(path, max_lines)
+    local f = io.open(path, "r")
+    if not f then return nil end
+    local buf = {}
+    local count = 0
+    for l in f:lines() do
+        table.insert(buf, l)
+        count = count + 1
+        if count > max_lines then
+            table.remove(buf, 1)
+            count = count - 1
+        end
+    end
+    f:close()
+    if #buf == 0 then return nil end
+    return table.concat(buf, "\n")
+end
+
+function IrcChatView:preloadHistory(target)
+    target = target or self._current_target or "*"
+    if self._buffers[target] and #self._buffers[target] > 0 then return end
+    local path = self:getLogPath(target)
+    local content = self:readLastLines(path, self._history_preload_lines)
+    if content and #content > 0 then
+        self._buffers[target] = content
+        if target == (self._current_target or "*") and self.scroll_text_w and self.scroll_text_w.text_widget then
+            self.scroll_text_w.text_widget:setText(content)
+        end
+    end
+end
+
 function IrcChatView:updateTitle()
     local tgt = self._current_target
     local new_title
@@ -106,6 +182,8 @@ end
 function IrcChatView:switchTarget(target)
     if not target then return end
     self:ensureBuffer(target)
+    -- Preload history (if any) when switching to a buffer
+    self:preloadHistory(target)
     self._current_target = target
     self:updateTitle()
     if self.scroll_text_w and self.scroll_text_w.text_widget then
@@ -124,6 +202,8 @@ function IrcChatView:appendLine(line, target)
     local buf = self._buffers[target]
     buf = (buf and #buf > 0) and (buf .. "\n" .. prefix .. line) or (prefix .. line)
     self._buffers[target] = buf
+    -- Persist to history
+    self:writeHistory(target, prefix .. line)
     if target == (self._current_target or "*") then
         if self.scroll_text_w and self.scroll_text_w.text_widget then
             self.scroll_text_w.text_widget:setText(buf)