-- init: bootstrap launcher.
--
-- Installed as startup.lua by the kernel. On boot it asks which program
-- to fetch, downloads it via the kernel, rewrites startup.lua so that
-- subsequent boots launch THAT program directly, then runs it.

local BASE_URL = "https://git.astrocore.space/root/nova-corp/raw/branch/main/"

local function fetch(path, dest)
    if fs.exists(dest) then shell.execute("rm", dest) end
    shell.execute("wget", BASE_URL .. path, dest)
    sleep(1)
end

local function ensureKernel()
    if not fs.exists("kernel.lua") then
        fetch("kernel.lua", "kernel.lua")
    end
    return require("kernel")
end

local function writeProgramStartup(programName)
    local src = ([[-- Auto-generated startup for "%s"
local BASE_URL = "%s"

local function fetch(path, dest)
    if fs.exists(dest) then shell.execute("rm", dest) end
    shell.execute("wget", BASE_URL .. path, dest)
    sleep(1)
end

-- Always refresh kernel + program so code updates flow through.
fetch("kernel.lua", "kernel.lua")
local kernel = require("kernel")
local program = kernel.addProgram("%s")

if type(program) ~= "table" then
    print("Program '%s' did not return a module table.")
    return
end

if program.start then program.start() end
if program.main then
    program.main()
else
    print("Program '%s' has no main() function.")
end
]]):format(programName, BASE_URL, programName, programName, programName)

    if fs.exists("startup.lua") then shell.execute("rm", "startup.lua") end
    local f = fs.open("startup.lua", "w")
    f.write(src)
    f.close()
end

local function prompt()
    term.clear()
    term.setCursorPos(1, 1)
    print("=== NovaCorp init ===")
    print("Enter program name to install (from /programs):")
    write("> ")
    local name = read()
    if not name or name == "" then
        print("No program entered. Staying on init.")
        return nil
    end
    return name
end

local function main()
    local name = prompt()
    if not name then return end

    local kernel = ensureKernel()

    print("Fetching program '" .. name .. "'...")
    local ok, programOrErr = pcall(kernel.addProgram, name)
    if not ok then
        print("Failed to download program: " .. tostring(programOrErr))
        print("Leaving init in place. Reboot to try again.")
        return
    end

    print("Replacing startup.lua...")
    writeProgramStartup(name)

    print("Done. Launching '" .. name .. "' now.")
    sleep(1)

    local program = programOrErr
    if type(program) == "table" then
        if program.start then pcall(program.start) end
        if program.main then pcall(program.main) end
    end
end

main()