-- recentf.lua
-- Track and access recently opened files (like Emacs recentf-mode)
-- ============================================================================

local recentf = {}

-- Configuration
recentf.config = {
    enabled = true,
    max_saved = 20,      -- Maximum number of recent files to track
    exclude_patterns = {  -- Patterns to exclude from recent files
        "^/tmp/",
        "%.git/",
        "COMMIT_EDITMSG$",
    },
}

-- Recent files list (most recent first)
recentf.list = {}

-- Check if a file should be excluded
local function should_exclude(filepath)
    if not filepath or filepath == "" then
        return true
    end
    -- Exclude *scratch* and other special buffers
    if filepath:match("^%*") then
        return true
    end
    for _, pattern in ipairs(recentf.config.exclude_patterns) do
        if filepath:match(pattern) then
            return true
        end
    end
    return false
end

-- Add a file to the recent list
function recentf.add(filepath)
    if should_exclude(filepath) then
        return
    end

    -- Remove if already in list (to move to front)
    for i, f in ipairs(recentf.list) do
        if f == filepath then
            table.remove(recentf.list, i)
            break
        end
    end

    -- Add to front
    table.insert(recentf.list, 1, filepath)

    -- Trim to max size
    while #recentf.list > recentf.config.max_saved do
        table.remove(recentf.list)
    end
end

-- Get the recent files list
function recentf.get_list()
    return recentf.list
end

-- Clear the recent files list
function recentf.clear()
    recentf.list = {}
end

-- Open a recent file by index (1-based)
function recentf.open(index)
    local idx = tonumber(index)
    if not idx or idx < 1 or idx > #recentf.list then
        return {success = false, message = "Invalid index: " .. tostring(index)}
    end

    local filepath = recentf.list[idx]
    return editor:execute_command("find-file", {filepath})
end

-- Format the recent files list for display
function recentf.format_list()
    local lines = {}
    for i, filepath in ipairs(recentf.list) do
        -- Shorten home directory
        local display = filepath:gsub("^" .. os.getenv("HOME"), "~")
        table.insert(lines, string.format("%2d: %s", i, display))
    end
    return lines
end

-- Setup function
function recentf.setup(opts)
    opts = opts or {}
    for k, v in pairs(opts) do
        recentf.config[k] = v
    end

    if not recentf.config.enabled then
        return
    end

    -- Register commands
    editor:register_command("recentf-open", "Open a recent file by number", function(args)
        if #args == 0 then
            -- List recent files
            local list = recentf.format_list()
            if #list == 0 then
                return {success = true, message = "No recent files"}
            end
            -- Show in echo area (up to 5 files)
            local preview = {}
            for i = 1, math.min(5, #list) do
                table.insert(preview, list[i])
            end
            local msg = table.concat(preview, " | ")
            if #list > 5 then
                msg = msg .. " ..."
            end
            return {success = true, message = msg}
        end
        return recentf.open(args[1])
    end, {}, true, "n")

    editor:register_command("recentf-list", "List all recent files", function(args)
        local list = recentf.format_list()
        if #list == 0 then
            return {success = true, message = "No recent files"}
        end
        -- Use echo area for multi-line display
        editor:set_echo_area(list)
        return {success = true, message = ""}
    end)

    editor:register_command("recentf-clear", "Clear the recent files list", function(args)
        recentf.clear()
        return {success = true, message = "Recent files list cleared"}
    end)

    -- Key binding (similar to Emacs)
    editor:bind_key("C-x C-r", "recentf-open", "Open recent file")

    -- Hook into find-file to track opens
    -- We'll expose a global function that the C++ can call
    lumacs.recentf_track = function(filepath)
        recentf.add(filepath)
    end

    print("[recentf] Package loaded")
end

-- Auto-setup with defaults
recentf.setup()

return recentf