--!strict
local datetime = require("@lune/datetime")
local fs = require("@lune/fs")
local net = require("@lune/net")

local result = require("./util/result")

--- Fetches the given file raw from the jecs github
local function fetch_raw(file: string): result.Identity<string>
    local res = net.request(`https://raw.githubusercontent.com/Ukendio/jecs/refs/heads/main/{file}`)
    if not res.ok then
        return result(false, `Not ok: {res.statusMessage} @ {res.statusCode}`)
    end
    return result(true, res.body)
end

local function save_if_diff(filepath: string, contents: string): result.Identity<nil>
    if not fs.metadata(filepath).exists then
        fs.writeFile(filepath, contents)
        return result(true, nil)
    end

    local existing = fs.readFile(filepath)
    if existing == contents then
        return result(false, "Contents are the same.")
    end

    fs.writeFile(filepath, contents)
    return result(true, nil)
end

local function round_to(n: number, places: number)
    local x = 10 ^ (places or 0)
    return math.round(n * x) / x
end

-- Returns an ISO 8601 date (YYYYmmddThhmmssZ)
local function iso_date_light(date: datetime.DateTime): string
    return date:formatUniversalTime("%Y%m%dT%H%M%SZ")
end

return {
    fetch_raw = fetch_raw,
    save_if_diff = save_if_diff,
    round_to = round_to,
    iso_date_light = iso_date_light,
}