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

local progress_bar = require("./util/progress")
local result = require("./util/result")
local shared = require("./shared")
local types = require("./types")

--- Synchronizes the required files from the jecs main branch.
local function sync(to: string): result.Identity<boolean>
    local now = datetime.now()
    local begin = os.clock()

    local progress = progress_bar
        .new()
        :withStage("init", "Initializing")
        :withStage("fetch", "Fetching latest files")
        :withStage("save", "Saving files")
        :withStage("version", "Pulling latest jecs version")
        :withStage("metadata", "Writing build metadata")
    progress:start() -- init

    if not fs.metadata(to).exists then
        fs.writeDir(to)
    end

    progress:nextStage() -- fetch

    local includes = {
        "jecs.luau",
        "README.md",
        "CHANGELOG.md",
        "LICENSE",
        ".luaurc",
    }

    local sources = {}

    for _, file in includes do
        local contents = shared.fetch_raw(file)
        if not contents.ok then
            progress:stop()
            stdio.ewrite(`🔥 Couldn't get the latest source for {file}:\n{contents.err}\n`)
            return result(false, `Couldn't get the latest source for {file}.`)
        end

        sources[file] = contents.val
    end

    progress:nextStage() -- save

    local sources_modified = {}
    local any_changed = false
    for file, contents in sources do
        local res = shared.save_if_diff(`{to}/{file}`, contents)
        if res.ok then
            any_changed = true
            table.insert(sources_modified, file)
        end
    end

    if not any_changed then
        progress:stop()
        local took = shared.round_to((os.clock() - begin) * 1_000, 2)
        print(
            `🕛 Finished synchronizing, no changes since latest source {stdio.style("dim")}(took {took}ms){stdio.style(
                "reset"
            )}`
        )
        return result(true, false)
    end

    local project_json = {
        name = "jecs-nightly",
        tree = {
            ["$path"] = "jecs.luau",
        },
    }
    local encoded_project_json = serde.encode("json", project_json)
    fs.writeFile(`{to}/default.project.json`, encoded_project_json)

    progress:nextStage() -- version

    local wally_contents = shared.fetch_raw("wally.toml")
    if not wally_contents.ok then
        progress:stop()
        stdio.ewrite(`🔥 Couldn't get the jecs wally manifest:\n{wally_contents.err}\n`)
        return result(false, `Couldn't get the jecs wally manifest:\n{wally_contents.err}`)
    end

    local parsed: types.WallyManifest = serde.decode("toml", wally_contents.val)

    progress:nextStage() -- metadata

    local version = `{parsed.package.version}-nightly.{shared.iso_date_light(now)}`
    local metadata = {
        version = version,
        modified = sources_modified,
    }
    local encoded_metadata = serde.encode("toml", metadata)
    fs.writeFile(`{to}/build.txt`, encoded_metadata)

    progress:stop() -- finish

    local took = shared.round_to((os.clock() - begin) * 1_000, 2)
    print(`🪨 Finished synchronizing {stdio.style("dim")}(took {took}ms){stdio.style("reset")}`)
    print(`Changed files:`)
    print(sources_modified)

    return result(true, true)
end

return sync