"""
RECON Enricher

Text to structured concepts via Gemini API. Saves JSON to data/concepts/{hash}/
BEFORE any DB operations. Uses 10-page windows, 4 API keys, 16 workers.

Resilience:
  - Exponential backoff with jitter for transient errors (429, 500, 503, timeout)
  - Permanent errors (JSON parse, auth) fail immediately without wasting retries
  - Window failures skip that window and continue — partial enrichment beats zero
  - Document marked enriched if ANY windows succeeded, failed only if ALL failed

Dependencies: google-generativeai
Config: processing.enrich_workers, processing.enrich_window_size, gemini, paths.concepts
"""
import json
import os
import random
import re
import time
import traceback
from concurrent.futures import ThreadPoolExecutor, as_completed

import google.generativeai as genai

from .utils import get_config, setup_logging
from .status import StatusDB

logger = setup_logging('recon.enricher')

# Docs stuck in "enriching" longer than this get reset to "extracted" for retry
STALE_ENRICHING_HOURS = 2

# ── Classification allowlists ───────────────────────────────────────────────
VALID_DOMAINS = {
    'Agriculture & Livestock', 'Civil Organization', 'Communications',
    'Food Systems', 'Foundational Skills', 'Logistics', 'Medical',
    'Navigation', 'Operations', 'Power Systems', 'Preservation & Storage',
    'Security', 'Shelter & Construction', 'Technology', 'Tools & Equipment',
    'Vehicles', 'Water Systems', 'Wilderness Skills',
}
VALID_KNOWLEDGE_TYPES = {'foundational', 'procedural', 'operational'}
VALID_COMPLEXITIES = {'basic', 'intermediate', 'advanced'}

DOMAIN_FALLBACK = 'Foundational Skills'
KNOWLEDGE_TYPE_FALLBACK = 'foundational'
COMPLEXITY_FALLBACK = 'basic'


def repair_json(text):
    """Attempt to repair common LLM JSON output issues including truncation."""
    # Remove control characters except newlines and tabs
    text = re.sub(r'[\x00-\x08\x0b\x0c\x0e-\x1f]', '', text)
    # Fix invalid JSON escape sequences (e.g. \e, \p, \c from Gemini)
    # Valid JSON escapes: \", \\, \/, \b, \f, \n, \r, \t, \uXXXX
    text = re.sub(r'\\(?!["\\/bfnrtu])', r'\\\\', text)
    # Remove trailing commas before } or ]
    text = re.sub(r',\s*([}\]])', r'\1', text)

    # Handle truncated JSON: try to find the last complete object in the array
    try:
        json.loads(text, strict=False)
        return text
    except json.JSONDecodeError:
        pass

    # Find the last complete }, then close the array
    # Walk backward to find the last valid closing brace
    last_complete = -1
    depth_brace = 0
    depth_bracket = 0
    in_string = False
    escape = False

    for i, ch in enumerate(text):
        if escape:
            escape = False
            continue
        if ch == '\\' and in_string:
            escape = True
            continue
        if ch == '"' and not escape:
            in_string = not in_string
            continue
        if in_string:
            continue
        if ch == '{':
            depth_brace += 1
        elif ch == '}':
            depth_brace -= 1
            if depth_brace == 0:
                last_complete = i
        elif ch == '[':
            depth_bracket += 1
        elif ch == ']':
            depth_bracket -= 1

    if last_complete > 0:
        truncated = text[:last_complete + 1].rstrip().rstrip(',')
        # Close any open arrays
        open_brackets = truncated.count('[') - truncated.count(']')
        truncated += ']' * open_brackets
        return truncated

    return text

ENRICH_PROMPT = """Extract knowledge concepts from this document text.

A concept is a SELF-CONTAINED piece of knowledge that can stand alone.

For each concept, provide ALL fields:

Required:
- content: Full text of the concept (complete procedure, definition, etc.)
- summary: 1-2 sentence summary
- title: Brief descriptive title
- domain: must be exactly one of: Agriculture & Livestock, Civil Organization, Communications, Food Systems, Foundational Skills, Logistics, Medical, Navigation, Operations, Power Systems, Preservation & Storage, Security, Shelter & Construction, Technology, Tools & Equipment, Vehicles, Water Systems, Wilderness Skills — return ONLY this exact string, no variations, no new domains, no underscores, no synonyms
  CRITICAL: Medical content (first aid, anatomy, pharmacology, herbs, veterinary, austere medicine) → Medical
  CRITICAL: Food growing, farming, animal husbandry, livestock → Agriculture & Livestock
  CRITICAL: Foraging, hunting, fishing, bushcraft, wilderness survival → Wilderness Skills
  CRITICAL: Food preservation, storage, canning, dehydration, processing → Preservation & Storage
  CRITICAL: Solar, wind, hydro, batteries, generators → Power Systems
  CRITICAL: Water sourcing, filtration, sanitation, purification → Water Systems
  CRITICAL: Building, carpentry, structural construction, shelter → Shelter & Construction
  CRITICAL: Tactical operations, mission execution, combat maneuvers, search & rescue → Operations
  CRITICAL: Governance, civil administration, community leadership → Civil Organization
  CRITICAL: Electronics, IT, computing, engineering → Technology
  CRITICAL: Hand tools, power tools, equipment maintenance → Tools & Equipment
  CRITICAL: Motor vehicles, aircraft, watercraft, vehicle maintenance → Vehicles
  CRITICAL: Radio, signals, networking, comms equipment → Communications
  CRITICAL: Supply chain, transport, distribution, inventory → Logistics
  CRITICAL: Physical security, OPSEC, threat assessment → Security
  CRITICAL: Map reading, orienteering, GPS, celestial navigation → Navigation
  CRITICAL: Cooking methods, food production, recipes, nutrition → Food Systems
- subdomain: Array of specific subcategories (up to 10)
- keywords: Array of 3-30 searchable terms
- knowledge_type: foundational | procedural | operational
    foundational — concepts, definitions, theory, background knowledge, explanations of how things work
    procedural — step-by-step techniques, instructions, how-to skills, methods you execute
    operational — application under real conditions, decision-making, mission execution, judgment calls in context
    Valid values are ONLY: foundational, procedural, operational — do not use any other values
- complexity: basic | intermediate | advanced
    basic — requires little or no prior knowledge, introductory material, simple concepts
    intermediate — requires some domain familiarity, assumes foundational knowledge is in place
    advanced — requires significant experience or expertise, high-stakes or highly technical material
    Valid values are ONLY: basic, intermediate, advanced — do not use any other values
- key_facts: Array of specific extractable claims, measurements, data points

Optional (include when present):
- scenario_applicable: Array from: tuesday_prepper, month_prepper, year_prepper, multi_year, eotwawki
- cross_domain_tags: Array from: sustainment, medical, security, communications, leadership, logistics, navigation, power_systems, water_systems, food_systems, tactical_ops, community_coordination
- chapter: Chapter name if identifiable
- page_ref: Page reference
- notes: Any additional context

EXAMPLES (knowledge_type + complexity):
- "Needle chest decompression procedure" → knowledge_type: "procedural", complexity: "advanced"
- "What is soil texture and why does it matter" → knowledge_type: "foundational", complexity: "basic"
- "Coordinating a fire team withdrawal under contact" → knowledge_type: "operational", complexity: "advanced"

Return JSON array. If no extractable concepts, return [].

Document text:
"""


class KeyRotator:
    def __init__(self, keys):
        self.keys = keys
        self.index = 0

    def next(self):
        if not self.keys:
            raise ValueError("No Gemini API keys configured")
        key = self.keys[self.index % len(self.keys)]
        self.index += 1
        return key


def enrich_window(text, key, config):
    genai.configure(api_key=key)
    model = genai.GenerativeModel(
        config['gemini']['model'],
        generation_config={"response_mime_type": config['gemini']['response_mime_type']}
    )
    response = model.generate_content(ENRICH_PROMPT + text)
    raw = response.text
    try:
        result = json.loads(raw, strict=False)
    except json.JSONDecodeError:
        repaired = repair_json(raw)
        result = json.loads(repaired, strict=False)
    # Filter out non-dict items (nested lists from truncated responses)
    if isinstance(result, list):
        result = [c for c in result if isinstance(c, dict)]
    return result


def _is_transient(error_str):
    """Classify whether an error is transient (worth retrying) or permanent."""
    s = error_str.lower()
    transient_signals = ['429', 'resource_exhausted', 'quota', 'rate',
                         '500', '503', 'unavailable', 'timeout',
                         'connection', 'reset by peer', 'broken pipe']
    return any(sig in s for sig in transient_signals)


def _retry_with_backoff(fn, max_retries=5, base_delay=5.0, max_delay=120.0):
    """Retry with exponential backoff + jitter for transient errors.

    Backoff: ~5s, ~10s, ~20s, ~40s, ~80s (total ~155s before giving up).
    Permanent errors (JSON parse, auth) raise immediately without retrying.
    """
    last_exc = None
    for attempt in range(max_retries):
        try:
            return fn()
        except Exception as e:
            last_exc = e
            err = str(e)
            if not _is_transient(err):
                raise  # permanent — don't waste retries
            if attempt < max_retries - 1:
                delay = min(base_delay * (2 ** attempt) + random.uniform(0, base_delay), max_delay)
                logger.info(f"    Transient error (attempt {attempt+1}/{max_retries}), "
                            f"retrying in {delay:.0f}s: {err[:120]}")
                time.sleep(delay)
            else:
                logger.warning(f"    Transient error, max retries exhausted: {err[:150]}")
    raise last_exc


def _reclassify_field(field_name, allowlist, concept, key, config, max_retries=3):
    """Retry Gemini up to max_retries to get a valid value for a specific field."""
    content = concept.get('content', concept.get('summary', ''))
    if isinstance(content, str):
        content = content[:400]
    else:
        content = str(content)[:400]
    title = concept.get('title', '(untitled)')
    allowlist_str = ', '.join(sorted(allowlist))

    for attempt in range(max_retries):
        try:
            prompt = (
                f"Your previous response for '{field_name}' was invalid. "
                f"You must return ONLY one of these exact strings: {allowlist_str}\n\n"
                f"Title: {title}\n"
                f"Content: {content}\n\n"
                f"Return ONLY the exact string, nothing else. No explanation, no punctuation, no quotes."
            )
            genai.configure(api_key=key)
            model = genai.GenerativeModel(
                config['gemini']['model'],
                generation_config={"response_mime_type": "text/plain"}
            )
            resp = model.generate_content(prompt)
            value = resp.text.strip().strip('"').strip("'").strip()
            if value in allowlist:
                return value
            # Try case-insensitive match for knowledge_type/complexity
            for valid in allowlist:
                if value.lower() == valid.lower():
                    return valid
        except Exception as e:
            err = str(e).lower()
            if any(s in err for s in ['429', 'quota', 'rate', '503']):
                time.sleep(min(3 * (2 ** attempt) + random.uniform(0, 2), 30))
            else:
                logger.warning(f"  Reclassify retry {attempt+1} for {field_name} failed: {e}")
    return None


def validate_and_fix_concepts(concepts, key, config):
    """Validate domain, knowledge_type, complexity on each concept.

    For invalid values: retry Gemini up to 3 times, then apply safe fallback.
    """
    for concept in concepts:
        if not isinstance(concept, dict):
            continue

        # ── Validate domain ─────────────────────────────────────────────
        domain = concept.get('domain')
        if isinstance(domain, list):
            # Legacy array format — find first valid or reclassify
            valid = [d for d in domain if d in VALID_DOMAINS]
            if valid:
                concept['domain'] = valid[0]
            else:
                new_val = _reclassify_field('domain', VALID_DOMAINS, concept, key, config)
                if new_val:
                    concept['domain'] = new_val
                else:
                    logger.warning(f"Invalid domain {domain} for '{concept.get('title', '?')}', using fallback")
                    concept['domain'] = DOMAIN_FALLBACK
        elif isinstance(domain, str):
            if domain not in VALID_DOMAINS:
                new_val = _reclassify_field('domain', VALID_DOMAINS, concept, key, config)
                if new_val:
                    concept['domain'] = new_val
                else:
                    logger.warning(f"Invalid domain '{domain}' for '{concept.get('title', '?')}', using fallback")
                    concept['domain'] = DOMAIN_FALLBACK
        else:
            concept['domain'] = DOMAIN_FALLBACK

        # ── Validate knowledge_type ─────────────────────────────────────
        kt = concept.get('knowledge_type', '')
        if isinstance(kt, str):
            kt = kt.lower().strip()
        else:
            kt = ''
        if kt not in VALID_KNOWLEDGE_TYPES:
            new_val = _reclassify_field('knowledge_type', VALID_KNOWLEDGE_TYPES, concept, key, config)
            if new_val:
                concept['knowledge_type'] = new_val
            else:
                logger.warning(f"Invalid knowledge_type '{kt}' for '{concept.get('title', '?')}', using fallback")
                concept['knowledge_type'] = KNOWLEDGE_TYPE_FALLBACK
        else:
            concept['knowledge_type'] = kt

        # ── Validate complexity ─────────────────────────────────────────
        cx = concept.get('complexity', '')
        if isinstance(cx, str):
            cx = cx.lower().strip()
        else:
            cx = ''
        if cx not in VALID_COMPLEXITIES:
            new_val = _reclassify_field('complexity', VALID_COMPLEXITIES, concept, key, config)
            if new_val:
                concept['complexity'] = new_val
            else:
                logger.warning(f"Invalid complexity '{cx}' for '{concept.get('title', '?')}', using fallback")
                concept['complexity'] = COMPLEXITY_FALLBACK
        else:
            concept['complexity'] = cx

    return concepts


def enrich_single(file_hash, db, config, key_rotator):
    doc = db.get_document(file_hash)
    if not doc:
        return False

    text_dir = os.path.join(config['paths']['text'], file_hash)
    concepts_dir = os.path.join(config['paths']['concepts'], file_hash)
    window_size = config['processing']['enrich_window_size']
    delay = config['processing']['rate_limit_delay']
    proc = config.get('processing', {})
    max_retries = proc.get('enrich_max_retries', proc.get('max_retries', 5))
    base_delay = proc.get('enrich_base_delay', 5.0)
    max_delay = proc.get('enrich_max_delay', 120.0)

    if not os.path.exists(text_dir):
        db.mark_failed(file_hash, f"Text directory not found: {text_dir}")
        return False

    db.update_status(file_hash, 'enriching')

    try:
        os.makedirs(concepts_dir, exist_ok=True)

        page_files = sorted([f for f in os.listdir(text_dir) if f.startswith('page_') and f.endswith('.txt')])
        if not page_files:
            db.mark_failed(file_hash, "No page files found")
            return False

        pages_text = []
        for pf in page_files:
            with open(os.path.join(text_dir, pf), encoding='utf-8') as f:
                pages_text.append(f.read())

        windows = []
        for i in range(0, len(pages_text), window_size):
            window_pages = pages_text[i:i + window_size]
            combined = "\n\n".join(f"--- Page {i + j + 1} ---\n{t}" for j, t in enumerate(window_pages))
            windows.append((i, combined))

        total_concepts = 0
        failed_windows = []

        for w_idx, (start_page, window_text) in enumerate(windows):
            window_file = os.path.join(concepts_dir, f"window_{w_idx+1:04d}.json")

            if os.path.exists(window_file):
                with open(window_file, encoding='utf-8') as f:
                    existing = json.load(f)
                total_concepts += len(existing)
                logger.debug(f"  Window {w_idx+1} already exists, skipping")
                continue

            if len(window_text.strip()) < 50:
                with open(window_file, 'w') as f:
                    json.dump([], f)
                continue

            # Attempt enrichment with backoff — failures skip the window, not the doc
            try:
                key = key_rotator.next()
                concepts = _retry_with_backoff(
                    lambda k=key: enrich_window(window_text, k, config),
                    max_retries=max_retries,
                    base_delay=base_delay,
                    max_delay=max_delay,
                )
            except Exception as e:
                failed_windows.append((w_idx + 1, str(e)[:100]))
                logger.warning(f"  Window {w_idx+1}/{len(windows)} failed: {e}")
                continue  # skip this window, keep going

            if not isinstance(concepts, list):
                concepts = [concepts] if isinstance(concepts, dict) else []
            concepts = [c for c in concepts if isinstance(c, dict)]

            # Validate domain, knowledge_type, complexity — retry then fallback
            validation_key = key_rotator.next()
            concepts = validate_and_fix_concepts(concepts, validation_key, config)

            for c_idx, concept in enumerate(concepts):
                concept['_window'] = w_idx + 1
                concept['_start_page'] = start_page + 1
                concept['_doc_hash'] = file_hash

            # JSON FIRST: save before anything else
            with open(window_file, 'w', encoding='utf-8') as f:
                json.dump(concepts, f, indent=2, ensure_ascii=False)

            total_concepts += len(concepts)
            logger.debug(f"  Window {w_idx+1}/{len(windows)}: {len(concepts)} concepts")
            time.sleep(delay)

        # Decide document status based on results
        meta = {
            'hash': file_hash,
            'total_windows': len(windows),
            'total_concepts': total_concepts,
            'failed_windows': len(failed_windows),
            'window_size': window_size,
            'timestamp': time.strftime('%Y-%m-%dT%H:%M:%SZ', time.gmtime()),
        }
        with open(os.path.join(concepts_dir, 'meta.json'), 'w') as f:
            json.dump(meta, f, indent=2)

        if total_concepts > 0 or not failed_windows:
            # Some concepts extracted, or all windows were empty — mark enriched
            error_msg = None
            if total_concepts == 0 and doc.get('page_count', 0) >= 3:
                error_msg = (f"0 concepts from {doc.get('page_count', '?')} pages — "
                             f"likely image-only PDF, may need manual review")
                logger.warning(f"  {doc['filename']}: {error_msg}")
            elif failed_windows:
                wins = ', '.join(str(w) for w, _ in failed_windows[:10])
                error_msg = (f"Partial: {len(failed_windows)}/{len(windows)} "
                             f"windows failed (windows {wins})")
                logger.warning(f"  {doc['filename']}: {error_msg}")
            db.update_status(file_hash, 'enriched', concepts_extracted=total_concepts,
                             error_message=error_msg)
            fw_note = f", {len(failed_windows)} windows failed" if failed_windows else ""
            logger.info(f"Enriched {doc['filename']}: {total_concepts} concepts "
                        f"from {len(windows)} windows{fw_note}")
            return True
        else:
            # Every window failed — document truly failed
            first_err = failed_windows[0][1] if failed_windows else 'unknown'
            db.mark_failed(file_hash,
                           f"All {len(windows)} windows failed: {first_err}")
            logger.error(f"  {doc['filename']}: all {len(windows)} windows failed")
            return False

    except Exception as e:
        logger.error(f"Enrichment failed for {file_hash}: {e}\n{traceback.format_exc()}")
        db.mark_failed(file_hash, str(e))
        return False


def _recover_stale_enriching(db, max_hours=STALE_ENRICHING_HOURS):
    """Reset docs stuck in enriching back to extracted so they get retried.

    This handles the case where a previous enrichment run crashed mid-document.
    The enricher skips already-completed window files, so no work is lost.
    """
    import sqlite3
    conn = db._get_conn()
    rows = conn.execute(
        "SELECT hash, filename FROM documents WHERE status = 'enriching'",
    ).fetchall()
    if not rows:
        return

    # Check extracted_at timestamp — if enriching started > max_hours ago, reset
    now = __import__('datetime').datetime.now(__import__('datetime').timezone.utc)
    reset = []
    for row in rows:
        doc = db.get_document(row['hash'])
        extracted_at = doc.get('extracted_at', '')
        if not extracted_at:
            reset.append(row)
            continue
        try:
            from datetime import datetime, timezone
            ts = datetime.fromisoformat(extracted_at)
            if ts.tzinfo is None:
                ts = ts.replace(tzinfo=timezone.utc)
            age_hours = (now - ts).total_seconds() / 3600
            if age_hours > max_hours:
                reset.append(row)
        except Exception:
            reset.append(row)

    for row in reset:
        conn.execute(
            "UPDATE documents SET status = 'extracted' WHERE hash = ?",
            (row['hash'],)
        )
        logger.warning(f"Recovered stale enriching doc: {row['filename']} ({row['hash'][:12]}...)")
    if reset:
        conn.commit()
        logger.info(f"Reset {len(reset)} stale enriching docs back to extracted")


def run_enrichment(workers=None, limit=None):
    config = get_config()
    db = StatusDB()
    workers = workers or config['processing']['enrich_workers']

    # Recover docs orphaned by previous crashed enrichment runs
    _recover_stale_enriching(db)

    keys = config.get('gemini_keys', [])
    if not keys:
        logger.error("No Gemini API keys configured in .env")
        return 0

    key_rotator = KeyRotator(keys)

    extracted = db.get_by_status('extracted', limit=limit)
    if not extracted:
        logger.info("No extracted documents to enrich")
        return 0

    logger.info(f"Enriching {len(extracted)} documents with {workers} workers, {len(keys)} API key(s)")
    success = 0

    with ThreadPoolExecutor(max_workers=workers) as pool:
        futures = {
            pool.submit(enrich_single, doc['hash'], StatusDB(), config, key_rotator): doc
            for doc in extracted
        }
        for future in as_completed(futures):
            doc = futures[future]
            try:
                if future.result():
                    success += 1
            except Exception as e:
                logger.error(f"Worker error for {doc['hash']}: {e}")

    logger.info(f"Enrichment complete: {success}/{len(extracted)} succeeded")
    return success