#include "samsung_vfd.h"
#include "charmaps.h"

#include "esphome/core/log.h"

#include <algorithm>
#include <cmath>

namespace esphome {
namespace samsung_vfd {

// Unaccented stand-ins for U+00C0..U+00FF (À..ÿ), one per code point. Used when
// the selected code table has no glyph for a character.
static const char LATIN1_FOLD[] = "AAAAAAACEEEEIIIIDNOOOOOxOUUUUYPs"
                                  "aaaaaaaceeeeiiiidnooooo/ouuuuypy";

static const char *const CODE_TABLE_NAMES[] = {"PC437", "PC850", "PC866", "PC737",
                                               "PC775", "CP10",  "PC864", "PC852"};

void SamsungVfd::setup() {
  this->resize_lines_();
  this->init_display_();
}

void SamsungVfd::dump_config() {
  ESP_LOGCONFIG(TAG, "Samsung VFD:");
  ESP_LOGCONFIG(TAG, "  Size: %u cols x %u rows", this->cols_, this->rows_);
  ESP_LOGCONFIG(TAG, "  Newline between lines: %s", YESNO(this->send_newlines_));
  ESP_LOGCONFIG(TAG, "  Brightness level: %u/4", this->brightness_level_);
  ESP_LOGCONFIG(TAG, "  Code table: %s", CODE_TABLE_NAMES[this->code_table_ & 7]);
  ESP_LOGCONFIG(TAG, "  International charset: %u", this->charset_);
  ESP_LOGCONFIG(TAG, "  User characters: %u", (unsigned) this->user_chars_.size());
}

// ---------- low-level output ----------

void SamsungVfd::write_str_(const std::string &s) {
  if (!s.empty())
    this->write_array(reinterpret_cast<const uint8_t *>(s.data()), s.size());
}

void SamsungVfd::send_esc_(uint8_t cmd) {
  const uint8_t b[] = {CMD_ESC, cmd};
  this->write_array(b, sizeof(b));
}

void SamsungVfd::send_esc_(uint8_t cmd, uint8_t arg) {
  const uint8_t b[] = {CMD_ESC, cmd, arg};
  this->write_array(b, sizeof(b));
}

void SamsungVfd::send_us_(uint8_t cmd) {
  const uint8_t b[] = {CMD_US, cmd};
  this->write_array(b, sizeof(b));
}

void SamsungVfd::send_us_(uint8_t cmd, uint8_t arg) {
  const uint8_t b[] = {CMD_US, cmd, arg};
  this->write_array(b, sizeof(b));
}

// ---------- initialisation ----------

void SamsungVfd::init_display_() {
  // ESC @ resets every setting, clears the screen and homes the cursor.
  this->send_esc_(ESC_INIT);
  this->apply_settings_();
  // Force the next flush to retransmit whatever is in the shadow buffer.
  this->invalidate_();
}

void SamsungVfd::apply_settings_() {
  this->send_esc_(ESC_CODE_TABLE, this->code_table_);
  this->send_esc_(ESC_INTL_CHARSET, this->charset_);
  this->send_user_chars_();
  this->send_us_(US_BRIGHTNESS, this->brightness_level_);
  this->send_us_(US_BLINK, this->on_ ? this->blink_ : BLINK_BLANK);
  this->send_annunciators_();
  if (this->mode_ != MODE_OVERWRITE)
    this->send_us_(this->mode_);
}

void SamsungVfd::send_user_chars_() {
  if (this->user_chars_.empty())
    return;
  for (const auto &uc : this->user_chars_) {
    // ESC & s n m a p1..p5: s = 1 byte per column, one character (n = m), 5 columns.
    const uint8_t b[] = {CMD_ESC, ESC_DEFINE_CHAR, 0x01, uc.code, uc.code, 0x05};
    this->write_array(b, sizeof(b));
    this->write_array(uc.columns.data(), uc.columns.size());
  }
  this->send_esc_(ESC_USER_FONT_SET, 0x01);
}

void SamsungVfd::send_annunciators_() {
  const uint32_t all = 0x1FFFFE;  // columns 1..20
  if ((this->annunciators_ & all) == all) {
    const uint8_t b[] = {CMD_US, US_ANNUNCIATOR, 0x01, 0x00};
    this->write_array(b, sizeof(b));
    return;
  }
  for (uint8_t col = 1; col <= 20; col++) {
    if (this->annunciators_ & (1UL << col)) {
      const uint8_t b[] = {CMD_US, US_ANNUNCIATOR, 0x01, col};
      this->write_array(b, sizeof(b));
    }
  }
}

void SamsungVfd::reinit() {
  this->init_display_();
  this->flush_();
}

// ---------- text encoding ----------

char SamsungVfd::encode_codepoint_(uint32_t cp) const {
  if (this->code_table_ < sizeof(CHARMAPS) / sizeof(CHARMAPS[0])) {
    const uint16_t *map = CHARMAPS[this->code_table_];
    if (map != nullptr) {
      for (uint8_t i = 0; i < 128; i++) {
        if (map[i] == cp)
          return static_cast<char>(0x80 + i);
      }
    }
  }
  if (cp == 0xA0)
    return ' ';
  if (cp >= 0xC0 && cp <= 0xFF)
    return LATIN1_FOLD[cp - 0xC0];
  return '?';
}

std::string SamsungVfd::encode(const std::string &text, bool keep_newlines) const {
  std::string out;
  out.reserve(text.size());
  size_t i = 0;
  while (i < text.size()) {
    auto c = static_cast<uint8_t>(text[i]);
    uint32_t cp;
    size_t len;
    if (c < 0x80) {
      cp = c;
      len = 1;
    } else if ((c & 0xE0) == 0xC0) {
      cp = c & 0x1F;
      len = 2;
    } else if ((c & 0xF0) == 0xE0) {
      cp = c & 0x0F;
      len = 3;
    } else if ((c & 0xF8) == 0xF0) {
      cp = c & 0x07;
      len = 4;
    } else {
      i++;  // stray continuation byte
      continue;
    }

    bool valid = i + len <= text.size();
    for (size_t k = 1; valid && k < len; k++) {
      auto cc = static_cast<uint8_t>(text[i + k]);
      if ((cc & 0xC0) != 0x80)
        valid = false;
      else
        cp = (cp << 6) | (cc & 0x3F);
    }
    if (!valid) {
      out.push_back('?');
      i++;
      continue;
    }
    i += len;

    if (cp == '\n') {
      out.push_back(keep_newlines ? '\n' : ' ');
    } else if (cp < 0x20 || cp == 0x7F) {
      out.push_back(' ');
    } else if (cp < 0x80) {
      out.push_back(static_cast<char>(cp));
    } else {
      out.push_back(this->encode_codepoint_(cp));
    }
  }
  return out;
}

// ---------- buffered text ----------

void SamsungVfd::resize_lines_() { this->lines_.assign(this->rows_, std::string(this->cols_, ' ')); }

std::string SamsungVfd::fit_(const std::string &text, bool centered) const {
  std::string line = text.substr(0, this->cols_);
  if (centered && line.size() < this->cols_)
    line.insert(0, (this->cols_ - line.size()) / 2, ' ');
  line.resize(this->cols_, ' ');
  return line;
}

void SamsungVfd::print(const std::string &raw, bool centered) {
  this->resize_lines_();
  const std::string text = this->encode(raw, true);

  // Lay the text out over the lines: split on explicit newlines, then wrap each
  // part into line-width chunks, breaking at the last space where possible.
  uint8_t row = 0;
  size_t i = 0;
  while (row < this->rows_) {
    size_t nl = text.find('\n', i);
    size_t end = (nl == std::string::npos) ? text.size() : nl;

    // A part always occupies at least one line, so "A\nB" puts B on line 2.
    do {
      size_t n = std::min<size_t>(this->cols_, end - i);
      size_t next = i + n;
      if (next < end && text[next] != ' ') {
        size_t sp = text.rfind(' ', next);
        if (sp != std::string::npos && sp > i) {
          n = sp - i;
          next = sp;
        }
      }
      this->lines_[row++] = this->fit_(text.substr(i, n), centered);
      i = next;
      while (i < end && text[i] == ' ')
        i++;  // a wrapped line never starts with a space
    } while (i < end && row < this->rows_);

    if (nl == std::string::npos)
      break;
    i = nl + 1;
  }

  this->flush_();
}

void SamsungVfd::print_line(uint8_t line, const std::string &text, bool centered) {
  if (line >= this->rows_) {
    ESP_LOGW(TAG, "print_line: line %u out of range (has %u lines)", line, this->rows_);
    return;
  }
  if (this->lines_.size() < this->rows_)
    this->resize_lines_();

  this->lines_[line] = this->fit_(this->encode(text, false), centered);
  this->flush_();
}

void SamsungVfd::clear() {
  this->resize_lines_();
  this->invalidate_();
  this->write_byte(CMD_CLEAR);
}

void SamsungVfd::flush_() {
  std::string payload;
  for (uint8_t r = 0; r < this->rows_; r++) {
    if (r != 0 && this->send_newlines_)
      payload += "\r\n";
    payload += this->lines_[r];
  }

  if (payload == this->last_payload_)
    return;  // nothing changed -> no re-send

  // No clear: every line is padded to the full width, so going home and
  // overwriting replaces all characters without the blank-screen flicker.
  // In overwrite mode the cursor wraps from the end of line 1 to line 2.
  this->write_byte(CMD_HOME);
  this->write_str_(payload);
  this->last_payload_ = payload;
}

// ---------- settings ----------

uint8_t SamsungVfd::brightness_to_level_(float b) {
  // Levels 1..4 = 40/60/80/100 %.
  int level = static_cast<int>(std::lround((b - 0.2f) / 0.2f));
  return static_cast<uint8_t>(std::max(1, std::min(4, level)));
}

void SamsungVfd::set_brightness(float brightness) {
  this->brightness_level_ = brightness_to_level_(brightness);
  this->send_us_(US_BRIGHTNESS, this->brightness_level_);
}

void SamsungVfd::set_blink(uint32_t ms) {
  // US E n: n * 13 ms on, n * 13 ms off. 0xFF means "off", so stop at 0xFE.
  this->blink_ = ms == 0 ? BLINK_OFF : static_cast<uint8_t>(std::max<uint32_t>(1, std::min<uint32_t>(0xFE, (ms + 6) / 13)));
  if (this->on_)
    this->send_us_(US_BLINK, this->blink_);
}

void SamsungVfd::turn_off() {
  this->on_ = false;
  this->send_us_(US_BLINK, BLINK_BLANK);
}

void SamsungVfd::turn_on() {
  this->on_ = true;
  this->send_us_(US_BLINK, this->blink_);
}

void SamsungVfd::set_annunciator(uint8_t column, bool state) {
  if (column > 20) {
    ESP_LOGW(TAG, "set_annunciator: column %u out of range (0 = all, 1..20)", column);
    return;
  }
  if (column == 0) {
    this->annunciators_ = state ? 0x1FFFFE : 0;
  } else if (state) {
    this->annunciators_ |= 1UL << column;
  } else {
    this->annunciators_ &= ~(1UL << column);
  }
  const uint8_t b[] = {CMD_US, US_ANNUNCIATOR, static_cast<uint8_t>(state ? 1 : 0), column};
  this->write_array(b, sizeof(b));
}

void SamsungVfd::set_code_table(CodeTable table) {
  this->code_table_ = table;
  this->send_esc_(ESC_CODE_TABLE, table);
}

void SamsungVfd::set_international_charset(InternationalCharset charset) {
  this->charset_ = charset;
  this->send_esc_(ESC_INTL_CHARSET, charset);
}

void SamsungVfd::define_char(uint8_t code, const std::array<uint8_t, 5> &columns) {
  if (code < 0x20 || code > 0x7E) {
    ESP_LOGW(TAG, "define_char: code 0x%02X out of range (0x20..0x7E)", code);
    return;
  }
  auto it = std::find_if(this->user_chars_.begin(), this->user_chars_.end(),
                         [code](const UserChar &uc) { return uc.code == code; });
  if (it != this->user_chars_.end()) {
    it->columns = columns;
  } else if (this->user_chars_.size() >= MAX_USER_CHARS) {
    ESP_LOGW(TAG, "define_char: at most %u user characters", MAX_USER_CHARS);
    return;
  } else {
    this->user_chars_.push_back(UserChar{code, columns});
  }
  const uint8_t b[] = {CMD_ESC, ESC_DEFINE_CHAR, 0x01, code, code, 0x05};
  this->write_array(b, sizeof(b));
  this->write_array(columns.data(), columns.size());
  this->send_esc_(ESC_USER_FONT_SET, 0x01);
  this->invalidate_();
}

void SamsungVfd::cancel_char(uint8_t code) {
  this->user_chars_.erase(std::remove_if(this->user_chars_.begin(), this->user_chars_.end(),
                                         [code](const UserChar &uc) { return uc.code == code; }),
                          this->user_chars_.end());
  this->send_esc_(ESC_CANCEL_CHAR, code);
  this->invalidate_();
}

// ---------- raw cursor and mode commands ----------

void SamsungVfd::home() { this->write_byte(CMD_HOME); }
void SamsungVfd::cursor_left() { this->write_byte(CMD_BS); }
void SamsungVfd::cursor_right() { this->write_byte(CMD_HT); }
void SamsungVfd::cursor_down() { this->write_byte(CMD_LF); }
void SamsungVfd::cursor_up() { this->send_us_(US_CURSOR_UP); }
void SamsungVfd::cursor_line_start() { this->write_byte(CMD_CR); }
void SamsungVfd::cursor_line_end() { this->send_us_(US_LINE_END); }
void SamsungVfd::cursor_bottom() { this->send_us_(US_BOTTOM); }

void SamsungVfd::set_cursor(uint8_t column, uint8_t line) {
  if (column >= this->cols_ || line >= this->rows_) {
    ESP_LOGW(TAG, "set_cursor: %u,%u out of range", column, line);
    return;
  }
  const uint8_t b[] = {CMD_US, US_SET_CURSOR, static_cast<uint8_t>(column + 1), static_cast<uint8_t>(line + 1)};
  this->write_array(b, sizeof(b));
}

void SamsungVfd::clear_cursor_line() {
  this->write_byte(CMD_CAN);
  this->invalidate_();
}

void SamsungVfd::set_display_mode(DisplayMode mode) {
  this->mode_ = mode;
  this->send_us_(mode);
  if (mode != MODE_OVERWRITE)
    ESP_LOGW(TAG, "Scroll mode set: print/print_line assume overwrite mode and may scroll the screen");
}

void SamsungVfd::select_peripheral(uint8_t n) {
  if (n < 1 || n > 3) {
    ESP_LOGW(TAG, "select_peripheral: %u out of range (1..3)", n);
    return;
  }
  this->send_esc_(ESC_PERIPHERAL, n);
}

void SamsungVfd::self_test() {
  this->send_us_(US_SELF_TEST);
  this->invalidate_();
  // The self-test resets every setting except user characters and ignores
  // input for about 20 s; restore settings and the screen afterwards.
  this->set_timeout("self_test", 21000, [this]() {
    this->apply_settings_();
    this->flush_();
  });
}

void SamsungVfd::write_text(const std::string &text) {
  this->write_str_(this->encode(text, false));
  this->invalidate_();
}

void SamsungVfd::write_raw(const std::vector<uint8_t> &data) { this->write_raw(data.data(), data.size()); }

void SamsungVfd::write_raw(const uint8_t *data, size_t len) {
  if (len != 0)
    this->write_array(data, len);
  this->invalidate_();
}

}  // namespace samsung_vfd
}  // namespace esphome