-- Resolve the game's patch notes for the launcher footer modal.
--
-- Sources, first hit wins:
--   1. The GitHub body the self-updater already fetched (Check.parseRelease)
--   2. PATCH_NOTES.md, if a build packed one
--   3. mobile/ios/app-repo.json -- CI copies each release's notes into
--      versions[].localizedDescription, so a checkout already has them
--      on disk even when the updater has not run

local Json = require("src.link.Json")

local PatchNotes = {}

PatchNotes.FILES = {
  "PATCH_NOTES.md",
  "assets/PATCH_NOTES.md",
}

PatchNotes.CACHE_FILES = {
  "updates/notes_cache.json",
}

PatchNotes.REPO_FILES = {
  "mobile/ios/app-repo.json",
}

local function nonempty(s)
  return type(s) == "string" and s:find("%S")
end

function PatchNotes.fromCheck(Check)
  if not (Check and Check.state) then return nil, nil end
  local ok, st = pcall(Check.state)
  st = (ok and type(st) == "table") and st or nil
  if not st then return nil, nil end
  if nonempty(st.notes) then
    return st.notes, st.latest
  end
  return nil, st.latest
end

local function readPath(path)
  local fs = love and love.filesystem
  if fs and fs.read then
    local ok, text = pcall(fs.read, path)
    if ok and nonempty(text) then return text end
  end
  local f = io.open(path, "rb")
  if not f then return nil end
  local text = f:read("*a")
  f:close()
  return nonempty(text) and text or nil
end

function PatchNotes.fromCache(engine)
  for _, path in ipairs(PatchNotes.CACHE_FILES) do
    local text = readPath(path)
    if text then
      local ok, doc = pcall(Json.decode, text)
      if ok and type(doc) == "table" then
        if engine and not engine:match("^0%.0%.0%-dev") then
          if doc[engine] and nonempty(doc[engine]) then
            return doc[engine], engine
          end
        else
          for ver, notes in pairs(doc) do
            if nonempty(notes) then
              return notes, ver
            end
          end
        end
      end
    end
  end
  return nil, nil
end

function PatchNotes.fromFile()
  for _, path in ipairs(PatchNotes.FILES) do
    local text = readPath(path)
    if text then return text end
  end
  return nil
end

-- Newest-first list of { version, notes } from the iOS sidecar.
function PatchNotes.parseRepo(jsonText)
  local doc = Json.decode(jsonText)
  if type(doc) ~= "table" or type(doc.apps) ~= "table" then return {} end
  local out = {}
  for _, app in ipairs(doc.apps) do
    if type(app) == "table" and type(app.versions) == "table" then
      for _, row in ipairs(app.versions) do
        if type(row) == "table" and nonempty(row.localizedDescription) then
          out[#out + 1] = {
            version = row.version,
            notes = row.localizedDescription,
          }
        end
      end
    end
  end
  return out
end

function PatchNotes.fromRepo(engine)
  for _, path in ipairs(PatchNotes.REPO_FILES) do
    local text = readPath(path)
    if text then
      local list = PatchNotes.parseRepo(text)
      if #list == 0 then return nil, nil end
      if engine and not engine:match("^0%.0%.0%-dev") then
        for _, row in ipairs(list) do
          if row.version == engine then
            return row.notes, row.version
          end
        end
        return nil, nil
      end
      return list[1].notes, list[1].version
    end
  end
  return nil, nil
end

function PatchNotes.body(Check)
  local Version = require("src.core.Version")
  local engine = (Version and Version.engine) or "?"

  local notes, ver = PatchNotes.fromCheck(Check)
  if notes and (engine:match("^0%.0%.0%-dev") or ver == engine or ver == nil) then
    return notes, ver or engine
  end

  notes, ver = PatchNotes.fromCache(engine)
  if notes then return notes, ver end

  notes = PatchNotes.fromFile()
  if notes then return notes, engine end

  notes, ver = PatchNotes.fromRepo(engine)
  if notes then return notes, ver end

  return "Unable to fetch patch notes.", engine
end

return PatchNotes