"""
ui_helpers.py
---------------------
Gradio UI support functions.

_safe_content          — defensive Gradio 6.x content extraction
get_history_text       — formats history list for the generation prompt
build_retrieval_query  — context-enriched query for follow-up questions
format_metrics         — builds the right-hand metrics panel markdown
"""
from config import CONFIDENCE_THRESHOLD, MAX_PROMPT_TOKENS


def _safe_content(raw) -> str:
  """
  Safely convert any Gradio message content value to a plain string.

  In Gradio 6.x, 'content' can be str, list of typed blocks
  (e.g. [{"type": "text", "text": "..."}]), or None. Calling
  .strip() directly on a list raises AttributeError — this
  function centralises the defensive conversion.
  """
  if raw is None:
      return ""
  if isinstance(raw, str):
      return raw.strip()
  if isinstance(raw, list):
    parts = []
    for block in raw:
      if isinstance(block, dict):
        parts.append(block.get("text", block.get("content", "")))
      elif isinstance(block, str):
        parts.append(block)
    return " ".join(filter(None, parts)).strip()
  return str(raw).strip()


def get_history_text(history: list, max_turns: int = 3) -> str:
  """
  Convert Gradio's history list to a readable conversation string
  for inclusion in the generation prompt.

  max_turns=3 keeps enough context to resolve references without
  overflowing the prompt budget. UI status placeholders
  ("🔍 Searching...", etc.) are filtered out so they never leak
  into the model's view of the conversation.
  """
  if not history:
      return ""

  UI_PREFIXES = ("🔍", "📚", "🌐", "❌", "⏳")

  lines  = []
  recent = history[-(max_turns * 2):]

  for msg in recent:
    if isinstance(msg, dict):
      role    = "User" if msg.get("role") == "user" else "Assistant"
      content = _safe_content(msg.get("content"))

    elif isinstance(msg, (list, tuple)) and len(msg) == 2:
      for role, raw in [("User", msg[0]), ("Assistant", msg[1])]:
        content = _safe_content(raw)
        if content and not content.startswith(UI_PREFIXES):
          lines.append(f"{role}: {content}")
      continue

    else:
      continue

    if content and not content.startswith(UI_PREFIXES):
        lines.append(f"{role}: {content}")

  return "\n".join(lines)


def build_retrieval_query(message: str, history: list) -> str:
  """
  Enrich the FAISS/Tavily query with prior-turn context — but ONLY
  when the current message looks like a genuine follow-up question.

  Requires ALL three signals: short message (≤7 words), a reference
  word (pronoun/article), and a question starter that presupposes
  a subject. This avoids polluting retrieval for brand-new topics.
  """
  if not history:
    return message

  words = message.lower().split()

  REFERENCE_WORDS = {
      "it", "they", "he", "she", "them", "those", "that",
      "this", "his", "her", "its", "their", "the",
  }
  QUESTION_STARTERS = {
      "who", "when", "where", "how", "why",
      "was", "did", "is", "are",
  }

  is_short      = len(words) <= 7
  has_reference = any(w in REFERENCE_WORDS for w in words)
  has_q_word    = bool(words) and words[0] in QUESTION_STARTERS

  if not (is_short and has_reference and has_q_word):
      return message

  last_user_msg = ""
  for msg in reversed(history):
      if isinstance(msg, dict) and msg.get("role") == "user":
          last_user_msg = _safe_content(msg.get("content"))
          break
      elif isinstance(msg, (list, tuple)) and len(msg) >= 1:
          last_user_msg = _safe_content(msg[0])
          break

  if last_user_msg and last_user_msg.lower() != message.lower():
      return f"{last_user_msg} {message}"

  return message


def format_metrics(
    source_type:    str   = "none",
    confidence:     float = 0.0,
    sources_count:  int   = 0,
    prompt_tokens:  int   = 0,
    t_retrieve:     float = 0.0,
    t_web:          float = 0.0,
    t_generate:     float = 0.0,
    t_total:        float = 0.0,
    tokens_per_sec: float = 0.0,
    output_tokens:  int   = 0,
    generating:     bool  = False,
    elapsed:        float = 0.0,
    token_so_far:   int   = 0,
    error:          str   = "",
) -> str:
  """
  Return a markdown string for the right-hand metrics panel.

  Three display modes: empty (no query yet), generating (live view
  during streaming), done (full breakdown after completion).
  """
  if error:
      return f"❌ **Error:** `{error}`"

  if source_type == "none" and not generating and t_total == 0.0:
      return "_Metrics will appear here during and after the response._"

  if generating:
    web_line = f"- Web search: **{t_web:.1f}s**\n" if t_web > 0 else ""
    return (
        f"⚡ **Generating...**\n\n"
        f"- Tokens out: **{token_so_far}**\n"
        f"- Elapsed: **{elapsed:.1f}s**\n"
        f"- Retrieval: **{t_retrieve*1000:.0f} ms**\n"
        f"{web_line}"
    )

  source_icon = "📚" if source_type == "faiss" else "🌐"
  source_name = "FAISS" if source_type == "faiss" else "Tavily"
  conf_status = "✓" if confidence >= CONFIDENCE_THRESHOLD else "✗ → web"

  lines = [
    f"**{source_icon} {source_name}** — sim `{confidence:.3f}` {conf_status}",
    "",
    "**⏱ Timing**",
    f"- Retrieval: `{t_retrieve * 1000:.0f} ms`",
  ]
  if t_web > 0:
      lines.append(f"- Web search: `{t_web:.2f}s`")
  lines += [
      f"- Generation: `{t_generate:.2f}s`",
      f"- **Total: `{t_total:.2f}s`**",
      "",
      "**🔢 Generation**",
      f"- Speed: **`{tokens_per_sec:.1f} tok/s`**",
      f"- Output tokens: `{output_tokens}`",
      f"- Prompt tokens: `{prompt_tokens}` / `{MAX_PROMPT_TOKENS}`",
  ]
  if sources_count > 0:
      lines.append(f"- Sources indexed: `{sources_count}`")

  return "\n".join(lines)