using System.Text.Encodings.Web;
using System.Text.Json;
using System.Text.Json.Nodes;
using System.Text.RegularExpressions;

var root = FindRoot();
var folder = Path.Combine(root, "src", "MeWeb.App", "Strings");
var options = new JsonSerializerOptions { WriteIndented = true, Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping };
var placeholder = new Regex(@"\{\d+\}");
const string Name = "me-web?";
var quotes = JsonNode.Parse(File.ReadAllText(Path.Combine(root, "data", "languages.json"))).AsArray()
  .ToDictionary(n => (string)n["code"], n => ((string)n["quotes"][0], (string)n["quotes"][1]));
var named = new Regex(@"(?:«[\u00A0\u202F ]|[""'“”„‟«»‹›「」『』‘’‚])?me-web\?(?:[\u00A0\u202F ]»|[""'“”„‟«»‹›「」『』‘’‚])?");

if (args.Length >= 1 && args[0] == "check") return Check();
if (args.Length == 3 && args[0] == "set") return Set(args[1], args[2]);
if (args.Length == 2 && args[0] == "merge") return Merge(args[1]);
if (args.Length == 3 && args[0] == "import") return Import(args[1], args[2]);
if (args.Length == 2 && args[0] == "drop") return Drop(args[1]);
if (args.Length == 1 && args[0] == "quote") return Quote();
Console.Error.WriteLine("usage: dotnet run tools/strings.cs -- check | set <Key> <values.json> | merge <keys.json> | import <code> <strings.json> | drop <Key> | quote");
Console.Error.WriteLine("  values.json maps a language code to its text; keys.json maps keys to such maps; strings.json maps keys to one language's text");
return 2;

int Check()
{
  var english = Read("en");
  var problems = 0;
  foreach (var file in Directory.GetFiles(folder, "*.json").OrderBy(f => f, StringComparer.Ordinal))
  {
    var code = Path.GetFileNameWithoutExtension(file);
    var values = Read(code);
    var (open, close) = quotes[code];
    var bare = values.Where(p => Bare(p.Value, open, close)).Select(p => p.Key).ToList();
    if (bare.Count > 0)
    {
      problems++;
      Console.WriteLine($"{code}: {Name} not between {open.Trim()} and {close.Trim()} in [{string.Join(", ", bare)}]");
    }
    if (code == "en") continue;
    var missing = english.Keys.Where(k => !values.ContainsKey(k)).ToList();
    var extra = values.Keys.Where(k => !english.ContainsKey(k)).ToList();
    var mismatched = english.Keys.Where(values.ContainsKey)
      .Where(k => !placeholder.Matches(english[k]).Select(m => m.Value).Order().SequenceEqual(placeholder.Matches(values[k]).Select(m => m.Value).Order())).ToList();
    if (missing.Count + extra.Count + mismatched.Count == 0) continue;
    problems++;
    Console.WriteLine($"{code}: missing [{string.Join(", ", missing)}] extra [{string.Join(", ", extra)}] placeholders [{string.Join(", ", mismatched)}]");
  }
  Console.WriteLine(problems == 0 ? $"strings: OK ({english.Count} keys)" : $"strings: {problems} language(s) to fix");
  return problems == 0 ? 0 : 1;
}

int Set(string key, string valuesPath)
{
  var values = JsonNode.Parse(File.ReadAllText(valuesPath)).AsObject();
  if (values["en"] is null) throw new InvalidOperationException("values.json must carry at least \"en\"");
  foreach (var (code, value) in values)
  {
    var strings = Read(code);
    strings[key] = (string)value;
    Write(code, strings);
  }
  Console.WriteLine($"{key}: set in {values.Count} language(s)");
  return 0;
}

int Merge(string path)
{
  var keys = JsonNode.Parse(File.ReadAllText(path)).AsObject();
  var byLanguage = new Dictionary<string, SortedDictionary<string, string>>();
  foreach (var (key, values) in keys)
  {
    if (values?["en"] is null) throw new InvalidOperationException($"{key} carries no \"en\"");
    foreach (var (code, value) in values.AsObject())
    {
      if (!byLanguage.TryGetValue(code, out var strings)) byLanguage[code] = strings = Read(code);
      strings[key] = (string)value;
    }
  }
  foreach (var (code, strings) in byLanguage) Write(code, strings);
  Console.WriteLine($"merge: {keys.Count} key(s) into {byLanguage.Count} language(s)");
  return 0;
}

int Import(string code, string path)
{
  var english = Read("en");
  var incoming = JsonNode.Parse(File.ReadAllText(path)).AsObject();
  var strings = Read(code);
  var unknown = new List<string>();
  foreach (var (key, value) in incoming)
  {
    if (!english.ContainsKey(key))
    {
      unknown.Add(key);
      continue;
    }
    strings[key] = (string)value;
  }
  Write(code, strings);
  Console.WriteLine($"import {code}: {incoming.Count - unknown.Count} key(s){(unknown.Count > 0 ? $", ignored unknown [{string.Join(", ", unknown)}]" : "")}");
  return unknown.Count == 0 ? 0 : 1;
}

int Drop(string key)
{
  var count = 0;
  foreach (var file in Directory.GetFiles(folder, "*.json"))
  {
    var code = Path.GetFileNameWithoutExtension(file);
    var strings = Read(code);
    if (!strings.Remove(key)) continue;
    Write(code, strings);
    count++;
  }
  Console.WriteLine($"{key}: dropped from {count} language(s)");
  return 0;
}

int Quote()
{
  var changed = 0;
  foreach (var file in Directory.GetFiles(folder, "*.json").OrderBy(f => f, StringComparer.Ordinal))
  {
    var code = Path.GetFileNameWithoutExtension(file);
    var (open, close) = quotes[code];
    var strings = Read(code);
    var quoted = new SortedDictionary<string, string>(strings.ToDictionary(p => p.Key, p => named.Replace(p.Value, open + Name + close)), StringComparer.Ordinal);
    if (quoted.SequenceEqual(strings)) continue;
    Write(code, quoted);
    changed++;
  }
  Console.WriteLine($"quote: {changed} language(s) changed");
  return 0;
}

static bool Bare(string text, string open, string close)
{
  for (var at = text.IndexOf(Name, StringComparison.Ordinal); at >= 0; at = text.IndexOf(Name, at + Name.Length, StringComparison.Ordinal))
    if (!text[..at].EndsWith(open, StringComparison.Ordinal) || !text[(at + Name.Length)..].StartsWith(close, StringComparison.Ordinal)) return true;
  return false;
}

SortedDictionary<string, string> Read(string code)
{
  var path = Path.Combine(folder, $"{code}.json");
  if (!File.Exists(path)) return new SortedDictionary<string, string>(StringComparer.Ordinal);
  var node = JsonNode.Parse(File.ReadAllText(path)).AsObject();
  return new SortedDictionary<string, string>(node.ToDictionary(p => p.Key, p => (string)p.Value), StringComparer.Ordinal);
}

void Write(string code, SortedDictionary<string, string> strings)
{
  var node = new JsonObject();
  foreach (var (key, value) in strings) node[key] = value;
  File.WriteAllText(Path.Combine(folder, $"{code}.json"), node.ToJsonString(options) + "\n");
}

static string FindRoot()
{
  var dir = new DirectoryInfo(Directory.GetCurrentDirectory());
  while (dir is not null && !File.Exists(Path.Combine(dir.FullName, "MeWeb.slnx"))) dir = dir.Parent;
  return dir?.FullName ?? throw new InvalidOperationException("run from inside the repository (MeWeb.slnx not found)");
}