"""
Prompt builder — assembles the full system prompt from all parts.

Build order (each section separated by a blank line):
    1. Global rules (format rules, roleplay rules)
    2. Character definition (identity, personality, speech, world, examples)
    3. Character-specific instructions (system_prompt field in JSON)
    4. User persona (optional)
    5. Memory (conversation summary + long-term memories)
Then passed as the system message, followed by:
    6. Recent conversation history
    7. Current user message
"""

import glob
import logging
import os
import re
from pathlib import Path
from typing import Any

from engine.static_files import load_static_json, load_static_text

logger = logging.getLogger(__name__)

ROOT = Path(__file__).resolve().parent.parent
CHARACTERS_DIR = ROOT / "characters"
PROMPTS_DIR = ROOT / "prompts"
ASSETS_DIR = ROOT / "assets"


# ── Character loading ──────────────────────────────────────────────────────────

def load_character(character_id: str) -> dict[str, Any]:
    """Load and return a character dict from characters/{character_id}.json."""
    if not isinstance(character_id, str) or not re.fullmatch(r"[a-zA-Z0-9_-]{1,100}", character_id):
        raise ValueError("Invalid character ID.")
    path = os.path.join(CHARACTERS_DIR, f"{character_id}.json")
    if not os.path.exists(path):
        raise FileNotFoundError(f"Character file not found: {path}")
    return load_static_json(path)


def list_characters() -> list[dict[str, str]]:
    """
    Discover all characters from the characters/ directory.
    Returns a list of dicts with id, name, and description.
    Skips any files that fail to parse (logs a warning instead of raising).
    """
    characters = []
    for path in sorted(glob.glob(os.path.join(CHARACTERS_DIR, "*.json"))):
        try:
            data = load_static_json(path)
            characters.append({
                "id":          data.get("id", os.path.splitext(os.path.basename(path))[0]),
                "name":        data.get("name", "Unknown"),
                "description": data.get("description", ""),
                "categories":  data.get("categories", []),
            })
        except Exception as e:
            logger.warning(f"[Characters] Skipping {path}: {e}")
    return characters


def get_avatar_path(character_id: str) -> str | None:
    """
    Return the first avatar image path found for a character.
    Logs a warning and returns None if no image exists — does not raise.
    """
    avatar_dir = os.path.join(ASSETS_DIR, "characters", character_id)
    for pattern in ("*.png", "*.jpg", "*.jpeg", "*.webp"):
        matches = glob.glob(os.path.join(avatar_dir, pattern))
        if matches:
            return sorted(matches)[0]
    logger.warning(
        f"[Avatar] No image found for '{character_id}' in '{avatar_dir}'. "
        "A placeholder will be shown in the UI."
    )
    return None


# ── Prompt sections ────────────────────────────────────────────────────────────

def build_global_prompt() -> str:
    """Load the global system prompt from prompts/system_prompt.txt."""
    path = os.path.join(PROMPTS_DIR, "system_prompt.txt")
    return load_static_text(path).strip()


def build_character_prompt(character: dict[str, Any]) -> str:
    """
    Build the character definition block from a character dict.
    Covers: identity, personality, speech style, behavior, world, roleplay rules,
    and a capped set of example dialogues.
    """
    name     = character.get("name", "Unknown")
    sections = [f"You are {name}."]

    # Identity
    identity = character.get("identity", {})
    if identity:
        parts = []
        if identity.get("role"):
            parts.append(f"Role: {identity['role']}")
        if identity.get("background"):
            parts.append(f"Background: {identity['background']}")
        if parts:
            sections.append("IDENTITY\n" + "\n".join(parts))

    # Personality
    personality = character.get("personality", [])
    if personality:
        sections.append("PERSONALITY\n" + ", ".join(personality))

    # Speech style
    speech = character.get("speech_style", {})
    if speech:
        parts = []
        if speech.get("tone"):
            parts.append(f"Tone: {', '.join(speech['tone'])}")
        if speech.get("formality"):
            parts.append(f"Formality: {speech['formality']}")
        if speech.get("sentence_style"):
            parts.append(f"Sentence style: {speech['sentence_style']}")
        flags = []
        if speech.get("uses_humor"):
            flags.append("humor")
        if speech.get("uses_rhetorical_questions"):
            flags.append("rhetorical questions")
        if speech.get("avoids_excessive_enthusiasm"):
            flags.append("avoids excessive enthusiasm")
        if flags:
            parts.append("Uses: " + ", ".join(flags))
        if parts:
            sections.append("SPEECH STYLE\n" + "\n".join(parts))

    # Behavior
    behavior = character.get("behavior", {})
    if behavior:
        lines = [
            f"- {k.replace('_', ' ')}: {v}"
            for k, v in behavior.items()
        ]
        sections.append("BEHAVIOR\n" + "\n".join(lines))

    # World
    world = character.get("world", {})
    if world:
        parts = []
        if world.get("universe"):
            parts.append(f"Universe: {world['universe']}")
        if world.get("setting"):
            parts.append(f"Setting: {world['setting']}")
        if world.get("description"):
            parts.append(world["description"])
        sections.append("WORLD\n" + "\n".join(parts))

    # Roleplay rules
    roleplay = character.get("roleplay", {})
    if roleplay:
        parts = []
        if roleplay.get("action_format"):
            parts.append(f"Action format: {roleplay['action_format']}")
        if roleplay.get("thought_format"):
            parts.append(f"Thought format: {roleplay['thought_format']}")
        if roleplay.get("break_character") is False:
            parts.append("Never break character.")
        if parts:
            sections.append("ROLEPLAY RULES\n" + "\n".join(parts))

    # Example dialogues (capped at 4 to manage token budget)
    examples = character.get("example_dialogues", [])
    if examples:
        lines = ["EXAMPLE DIALOGUES"]
        for ex in examples[:4]:
            lines.append(f'User: {ex["user"]}')
            lines.append(f'{name}: {ex["character"]}')
            lines.append("")
        sections.append("\n".join(lines).strip())

    return "\n\n".join(sections)


def build_character_specific_prompt(character: dict[str, Any]) -> str:
    """
    Return the character's system_prompt field.
    This is character-specific fine-tuning on top of the global rules —
    it does not replace them.
    """
    sp = character.get("system_prompt", "").strip()
    if sp:
        return f"ADDITIONAL CHARACTER NOTES\n{sp}"
    return ""


def build_persona_prompt(persona: dict[str, str] | None) -> str:
    """
    Build the user persona section.
    Returns an empty string if persona is absent or all fields are blank.
    """
    if not persona or not any(persona.values()):
        return ""
    lines = ["THE USER IS PLAYING THE ROLE OF:"]
    for key in ("name", "age", "gender", "personality", "background"):
        val = persona.get(key, "").strip()
        if val:
            lines.append(f"{key.capitalize()}: {val}")
    return "\n".join(lines)


def build_memory_prompt(summary: str, long_term_memory: list[dict]) -> str:
    """Build the memory section from conversation summary and long-term memories."""
    parts = []
    if summary:
        parts.append(f"CONVERSATION SUMMARY\n{summary}")
    if long_term_memory:
        lines = ["LONG-TERM MEMORY"]
        for mem in long_term_memory:
            importance = mem.get("importance", "medium").upper()
            content    = mem.get("content", "")
            lines.append(f"[{importance}] {content}")
        parts.append("\n".join(lines))
    return "\n\n".join(parts)

# ── Language instruction ───────────────────────────────────────────────────────

# Maps lowercase language name → display label (native name in parentheses)
_LANG_LABELS: dict[str, str] = {
    "turkish":  "Turkish (Türkçe)",
    "french":   "French (Français)",
    "german":   "German (Deutsch)",
    "italian":  "Italian (Italiano)",
    "russian":  "Russian (Русский)",
    "chinese":  "Chinese (中文)",
}


def build_language_prompt(language: str) -> str:
    """
    Return a language-enforcement instruction for the system prompt.
    Returns an empty string for English (the default behaviour of most models).
    """
    key = language.strip().lower()
    if not key or key == "english":
        return ""
    label = _LANG_LABELS.get(key, language)
    return (
        f"LANGUAGE\n"
        f"You must always respond in {label}. "
        f"This applies to all dialogue, actions, and internal thoughts — "
        f"regardless of what language the user writes in."
    )

# ── Final assembly ─────────────────────────────────────────────────────────────

def build_messages(
    character:        dict[str, Any],
    persona:          dict[str, str] | None,
    summary:          str,
    long_term_memory: list[dict],
    recent_messages:  list[dict],
    current_message:  str,
    language:         str = "English",
) -> list[dict[str, str]]:
    """
    Assemble the full messages array to send to the LLM.

    System prompt build order:
        1. Global rules (format rules, roleplay rules)
        2. Character definition (identity, personality, speech, world, examples)
        3. Character-specific instructions (system_prompt field in JSON)
        4. User persona (optional)
        5. Memory (summary + long-term)
        6. Language instruction (omitted for English)
    Then:
        7. Recent conversation history
        8. Current user message
    """
    system_sections: list[str] = []

    global_prompt = build_global_prompt()
    if global_prompt:
        system_sections.append(global_prompt)

    char_prompt = build_character_prompt(character)
    if char_prompt:
        system_sections.append(char_prompt)

    char_specific = build_character_specific_prompt(character)
    if char_specific:
        system_sections.append(char_specific)

    persona_prompt = build_persona_prompt(persona)
    if persona_prompt:
        system_sections.append(persona_prompt)

    memory_prompt = build_memory_prompt(summary, long_term_memory)
    if memory_prompt:
        system_sections.append(memory_prompt)

    # Language instruction goes last — recency helps models follow it reliably
    lang_prompt = build_language_prompt(language)
    if lang_prompt:
        system_sections.append(lang_prompt)

    system_content = "\n\n".join(system_sections)

    messages: list[dict[str, str]] = [{"role": "system", "content": system_content}]
    messages.extend(recent_messages)
    messages.append({"role": "user", "content": current_message})

    logger.debug(
        f"[PromptBuilder] Built: {len(system_content)} chars system | "
        f"{len(system_sections)} sections | "
        f"{len(recent_messages)} history turns | "
        f"language='{language}'"
    )
    return messages