-- Lumacs Configuration File
-- This file is executed on startup and allows you to customize keybindings,
-- create commands, and extend the editor with Lua.

print("Loading init.lua...")

-- Example: Custom keybindings
-- Syntax: bind_key("key", function() ... end)

-- Emacs-style navigation (Ctrl+N/P for next/previous line)
bind_key("C-n", function()
    editor:move_down()
    message("Moved down")
end)

bind_key("C-p", function()
    editor:move_up()
    message("Moved up")
end)

bind_key("C-f", function()
    editor:move_right()
end)

bind_key("C-b", function()
    editor:move_left()
end)

-- Emacs-style line navigation
bind_key("C-a", function()
    editor:move_to_line_start()
end)

bind_key("C-e", function()
    editor:move_to_line_end()
end)

-- Custom command: Save buffer
bind_key("C-s", function()
    local buf = editor.buffer
    if buf:save() then
        message("Buffer saved: " .. buf:name())
    else
        message("Failed to save buffer")
    end
end)

-- Custom command: Insert timestamp
bind_key("C-t", function()
    local cursor_pos = editor.cursor
    local timestamp = os.date("%Y-%m-%d %H:%M:%S")
    editor.buffer:insert(cursor_pos, timestamp)
    message("Inserted timestamp")
end)

-- Example: Helper functions you can define
function goto_line(line_num)
    local pos = lumacs.Position(line_num - 1, 0)
    editor:set_cursor(pos)
    message("Jumped to line " .. line_num)
end

-- Example: Buffer inspection
function buffer_info()
    local buf = editor.buffer
    local cursor = editor.cursor

    message(string.format(
        "Buffer: %s | Lines: %d | Cursor: %d,%d | Modified: %s",
        buf:name(),
        buf:line_count(),
        cursor.line + 1,
        cursor.column + 1,
        buf:is_modified() and "yes" or "no"
    ))
end

-- Bind to show buffer info
bind_key("C-i", buffer_info)

-- Search helper function
function find_next(query)
    local buf = editor.buffer
    local cursor = editor.cursor
    -- Start searching AFTER the current cursor position to find the next occurrence
    -- Otherwise we might find the same one if we are sitting on it.
    -- A simple way is to advance column by 1 for the search start.
    local search_start = lumacs.Position(cursor.line, cursor.column + 1)
    
    -- If at end of line, search from start of next line is handled by find() implementation? 
    -- Buffer::find currently implements simple linear search from a position.
    -- If column is beyond end, it should handle it. Let's trust the C++ impl or adjust.
    
    local res = buf:find(query, search_start)
    if res then
        editor.cursor = res.start
        message("Found '" .. query .. "' at " .. res.start.line .. ":" .. res.start.column)
        -- Optional: Highlight the found range?
    else
        message("'" .. query .. "' not found")
    end
end

-- Example binding: Find "TODO"
bind_key("C-o", function() find_next("TODO") end)

-- Line swapping functions (like Emacs M-up/down or VS Code Alt+arrows)
function swap_line_up()
    local buf = editor.buffer
    local cursor = editor.cursor

    -- Can't move first line up
    if cursor.line == 0 then
        message("Already at first line")
        return
    end

    message("DEBUG: Starting swap_line_up, cursor at line " .. cursor.line)

    -- Get the current line and above line text
    local current_line = buf:line(cursor.line)
    local above_line = buf:line(cursor.line - 1)

    -- Strategy: Replace both lines with them swapped
    -- Delete from start of line above to end of current line (not including next line)
    local delete_start = lumacs.Position(cursor.line - 1, 0)
    local delete_end = lumacs.Position(cursor.line, string.len(current_line))

    local range = lumacs.Range(delete_start, delete_end)
    buf:erase(range)

    -- Insert them back in swapped order
    -- Add extra newline if above_line is empty to preserve it
    local insert_pos = lumacs.Position(cursor.line - 1, 0)
    local text = current_line .. "\n" .. above_line
    if above_line == "" then
        text = text .. "\n"
    end
    buf:insert(insert_pos, text)

    -- Move cursor up to follow the line
    editor.cursor = lumacs.Position(cursor.line - 1, cursor.column)
    message("Swapped line up")
end

function swap_line_down()
    local buf = editor.buffer
    local cursor = editor.cursor

    -- Can't move last line down
    if cursor.line >= buf:line_count() - 1 then
        message("Already at last line")
        return
    end

    -- Get the current line and the line below
    local current_line = buf:line(cursor.line)
    local below_line = buf:line(cursor.line + 1)

    -- Strategy: Replace both lines with them swapped
    -- Delete from start of current line to end of line below (not including line after)
    local delete_start = lumacs.Position(cursor.line, 0)
    local delete_end = lumacs.Position(cursor.line + 1, string.len(below_line))
    local range = lumacs.Range(delete_start, delete_end)
    buf:erase(range)

    -- Insert them back in swapped order
    -- Add extra newline if current_line is empty to preserve it
    local insert_pos = lumacs.Position(cursor.line, 0)
    local text = below_line .. "\n" .. current_line
    if current_line == "" then
        text = text .. "\n"
    end
    buf:insert(insert_pos, text)

    -- Move cursor down to follow the line
    editor.cursor = lumacs.Position(cursor.line + 1, cursor.column)
    message("Swapped line down")
end

-- Bind to M-ArrowUp and M-ArrowDown (Meta/Alt + arrows)
bind_key("M-ArrowUp", swap_line_up)
bind_key("M-ArrowDown", swap_line_down)

-- Window Management Bindings
bind_key("C-w", function()
    editor:next_window()
    -- message("Switched window")
end)

-- Split horizontal (like Emacs C-x 2, simplified to M-2)
bind_key("M-2", function()
    editor:split_horizontally()
    message("Split horizontally")
end)

-- Split vertical (like Emacs C-x 3, simplified to M-3)
bind_key("M-3", function()
    editor:split_vertically()
    message("Split vertically")
end)

-- Close window (like Emacs C-x 0, simplified to M-0)
bind_key("M-0", function()
    editor:close_window()
    message("Closed window")
end)

-- Command Mode (Minibuffer)
bind_key("M-x", function()
    editor:command_mode()
end)

-- Undo/Redo
bind_key("C-z", function()
    if editor:undo() then
        message("Undid change")
    else
        message("Nothing to undo")
    end
end)

bind_key("C-y", function()
    if editor:redo() then
        message("Redid change")
    else
        message("Nothing to redo")
    end
end)

-- Simple syntax highlighter for demonstration
function highlight_buffer()
    local buf = editor.buffer
    buf:clear_styles()  -- Clear existing styles

    -- Keywords to highlight
    local keywords = {
        "function", "local", "end", "if", "then", "else", "elseif",
        "for", "while", "do", "return", "break", "and", "or", "not"
    }

    -- Highlight each line
    for line_num = 0, buf:line_count() - 1 do
        local line_text = buf:line(line_num)

        -- Highlight keywords
        for _, keyword in ipairs(keywords) do
            local start_pos = 1
            while true do
                -- Find keyword with word boundaries
                local pattern = "%f[%w]" .. keyword .. "%f[%W]"
                local pos = string.find(line_text, pattern, start_pos)
                if not pos then break end

                local range = lumacs.Range(
                    lumacs.Position(line_num, pos - 1),
                    lumacs.Position(line_num, pos + #keyword - 1)
                )

                buf:set_style(range, lumacs.TextAttribute(lumacs.ColorType.Keyword, 0))
                start_pos = pos + #keyword
            end
        end

        -- Highlight strings (simple version - just finds quoted text)
        local start_pos = 1
        while true do
            local quote_start = string.find(line_text, '"', start_pos, true)
            if not quote_start then break end

            local quote_end = string.find(line_text, '"', quote_start + 1, true)
            if not quote_end then break end

            local range = lumacs.Range(
                lumacs.Position(line_num, quote_start - 1),
                lumacs.Position(line_num, quote_end)
            )

            buf:set_style(range, lumacs.TextAttribute(lumacs.ColorType.String, 0))
            start_pos = quote_end + 1
        end

        -- Highlight comments
        local comment_pos = string.find(line_text, "%-%-", 1, true)
        if comment_pos then
            local range = lumacs.Range(
                lumacs.Position(line_num, comment_pos - 1),
                lumacs.Position(line_num, #line_text)
            )

            buf:set_style(range, lumacs.TextAttribute(lumacs.ColorType.Comment, 0))
        end
    end
end

-- Auto-highlighting using events!
-- Register event handler to automatically highlight when buffer loads or changes
editor.buffer:on_buffer_event(function(event_data)
    local buf = editor.buffer

    -- Auto-highlight on these events
    if event_data.event == lumacs.BufferEvent.Loaded or
       event_data.event == lumacs.BufferEvent.LanguageChanged then
        -- Only highlight Lua files automatically
        if buf.language == "lua" then
            highlight_buffer()
            print(string.format("[Auto-highlight] Applied to %s buffer", buf.language))
        end
    end
end)

-- Manual highlight key (C-l) for any language
bind_key("C-l", function()
    highlight_buffer()

    -- Debug: Count applied styles
    local buf = editor.buffer
    local styles_count = 0
    for line = 0, buf:line_count() - 1 do
        local styles = buf:get_line_styles(line)
        styles_count = styles_count + #styles
    end

    message(string.format("Highlighted! Applied %d styled ranges", styles_count))
end)

-- Welcome message
message("Lumacs ready! C-s=save, C-l=highlight, M-arrows=swap lines, C-i=info, Esc/Q=quit")