mtg_python_deckbuilder/code/deck_builder/builder_utils.py

"""Utility helper functions for deck builder.

This module houses pure/stateless helper logic that was previously embedded
inside the large builder.py module. Extracting them here keeps the DeckBuilder
class leaner and makes the logic easier to test independently.

Only import lightweight standard library modules here to avoid import cycles.
"""
from __future__ import annotations

from typing import Dict, Iterable
import re
import ast
import random as _rand

from . import builder_constants as bc
import math

COLOR_LETTERS = ['W', 'U', 'B', 'R', 'G']


def parse_theme_tags(val) -> list[str]:
	"""Robustly parse a themeTags cell that may be a list, nested list, or string-repr.

	Handles formats like:
	  ['Tag1', 'Tag2']
	  "['Tag1', 'Tag2']"
	  Tag1, Tag2
	Returns list of stripped string tags (may be empty)."""
	if isinstance(val, list):
		flat: list[str] = []
		for v in val:
			if isinstance(v, list):
				flat.extend(str(x) for x in v)
			else:
				flat.append(str(v))
		return [s.strip() for s in flat if s and str(s).strip()]
	if isinstance(val, str):
		s = val.strip()
		# Try literal list first
		try:
			parsed = ast.literal_eval(s)
			if isinstance(parsed, list):
				return [str(x).strip() for x in parsed if str(x).strip()]
		except Exception:
			pass
		# Fallback comma split
		if s.startswith('[') and s.endswith(']'):
			s = s[1:-1]
		parts = [p.strip().strip("'\"") for p in s.split(',')]
		out: list[str] = []
		for p in parts:
			if not p:
				continue
			clean = re.sub(r"^[\[\s']+|[\]\s']+$", '', p)
			if clean:
				out.append(clean)
		return out
	return []


def normalize_theme_list(raw) -> list[str]:
	"""Parse then lowercase + strip each tag."""
	tags = parse_theme_tags(raw)
	return [t.lower().strip() for t in tags if t and t.strip()]


def compute_color_source_matrix(card_library: Dict[str, dict], full_df) -> Dict[str, Dict[str, int]]:
	"""Build a matrix mapping land name -> {color: 0/1} indicating if that land
	can (reliably) produce each color.

	Heuristics:
	  - Presence of basic land types in type line grants that color.
	  - Text containing "add one mana of any color/colour" grants all colors.
	  - Explicit mana symbols in rules text (e.g. "{R}") grant that color.

	Parameters
	----------
	card_library : Dict[str, dict]
		Current deck card entries (expects 'Card Type' and 'Count').
	full_df : pandas.DataFrame | None
		Full card dataset used for type/text lookups. May be None/empty.
	"""
	matrix: Dict[str, Dict[str, int]] = {}
	lookup = {}
	if full_df is not None and not getattr(full_df, 'empty', True) and 'name' in full_df.columns:
		for _, r in full_df.iterrows():  # type: ignore[attr-defined]
			nm = str(r.get('name', ''))
			if nm and nm not in lookup:
				lookup[nm] = r
	for name, entry in card_library.items():
		if 'land' not in str(entry.get('Card Type', '')).lower():
			continue
		row = lookup.get(name, {})
		tline = str(row.get('type', row.get('type_line', ''))).lower()
		text_field = str(row.get('text', row.get('oracleText', ''))).lower()
		colors = {c: 0 for c in COLOR_LETTERS}
		if 'plains' in tline:
			colors['W'] = 1
		if 'island' in tline:
			colors['U'] = 1
		if 'swamp' in tline:
			colors['B'] = 1
		if 'mountain' in tline:
			colors['R'] = 1
		if 'forest' in tline:
			colors['G'] = 1
		if 'add one mana of any color' in text_field or 'add one mana of any colour' in text_field:
			for k in colors:
				colors[k] = 1
		for sym, c in [(' {w}', 'W'), (' {u}', 'U'), (' {b}', 'B'), (' {r}', 'R'), (' {g}', 'G')]:
			if sym in text_field:
				colors[c] = 1
		matrix[name] = colors
	return matrix


def compute_spell_pip_weights(card_library: Dict[str, dict], color_identity: Iterable[str]) -> Dict[str, float]:
	"""Compute relative colored mana pip weights from non-land spells.

	Hybrid symbols are split evenly among their component colors. If no colored
	pips are found we fall back to an even distribution across the commander's
	color identity (or 0s if identity empty).
	"""
	pip_counts = {c: 0 for c in COLOR_LETTERS}
	total_colored = 0.0
	for entry in card_library.values():
		ctype = str(entry.get('Card Type', ''))
		if 'land' in ctype.lower():
			continue
		mana_cost = entry.get('Mana Cost') or entry.get('mana_cost') or ''
		if not isinstance(mana_cost, str):
			continue
		for match in re.findall(r'\{([^}]+)\}', mana_cost):
			sym = match.upper()
			if len(sym) == 1 and sym in pip_counts:
				pip_counts[sym] += 1
				total_colored += 1
			else:
				if '/' in sym:
					parts = [p for p in sym.split('/') if p in pip_counts]
					if parts:
						weight_each = 1 / len(parts)
						for p in parts:
							pip_counts[p] += weight_each
							total_colored += weight_each
	if total_colored <= 0:
		colors = [c for c in color_identity if c in pip_counts]
		if not colors:
			return {c: 0.0 for c in pip_counts}
		share = 1 / len(colors)
		return {c: (share if c in colors else 0.0) for c in pip_counts}
	return {c: (pip_counts[c] / total_colored) for c in pip_counts}


__all__ = [
	'compute_color_source_matrix',
	'compute_spell_pip_weights',
	'parse_theme_tags',
	'normalize_theme_list',
	'prefer_owned_first',
	'compute_adjusted_target',
	'normalize_tag_cell',
	'sort_by_priority',
	'COLOR_LETTERS',
	'tapped_land_penalty',
	'replacement_land_score',
	'build_tag_driven_suggestions',
	'select_color_balance_removal',
	'color_balance_addition_candidates',
	'basic_land_names',
	'count_basic_lands',
	'choose_basic_to_trim',
	'enforce_land_cap',
	'is_color_fixing_land',
	'weighted_sample_without_replacement',
	'count_existing_fetches',
	'select_top_land_candidates',
]


def compute_adjusted_target(category_label: str,
                            original_cfg: int,
                            existing: int,
                            output_func,
                            plural_word: str | None = None,
                            bonus_max_pct: float = 0.2,
                            rng=None) -> tuple[int, int]:
	"""Compute how many additional cards of a category to add applying a random bonus.

	Returns (to_add, bonus). to_add may be 0 if target already satisfied and bonus doesn't push above existing.

	Parameters
	----------
	category_label : str
		Human-readable label (e.g. 'Ramp', 'Removal').
	original_cfg : int
		Configured target count.
	existing : int
		How many already present.
	output_func : callable
		Function for emitting messages (e.g. print or logger).
	plural_word : str | None
		Phrase used in messages for plural additions. If None derives from label (lower + ' spells').
	bonus_max_pct : float
		Upper bound for random bonus percent (default 0.2 => up to +20%).
	rng : object | None
		Optional random-like object with uniform().
	"""
	if original_cfg <= 0:
		return 0, 0
	plural_word = plural_word or f"{category_label.lower()} spells"
	# Random bonus between 0 and bonus_max_pct inclusive
	roll = (rng.uniform(0.0, bonus_max_pct) if rng else _rand.uniform(0.0, bonus_max_pct))
	bonus = math.ceil(original_cfg * roll) if original_cfg > 0 else 0
	if existing >= original_cfg:
		to_add = original_cfg + bonus - existing
		if to_add <= 0:
			output_func(f"{category_label} target met ({existing}/{original_cfg}). Random bonus {bonus} -> no additional {plural_word} needed.")
			return 0, bonus
		output_func(f"{category_label} target met ({existing}/{original_cfg}). Adding random bonus {bonus}; scheduling {to_add} extra {plural_word}.")
		return to_add, bonus
	remaining_need = original_cfg - existing
	to_add = remaining_need + bonus
	output_func(f"Existing {category_label.lower()} {existing}/{original_cfg}. Remaining need {remaining_need}. Random bonus {bonus}. Adding {to_add} {plural_word}.")
	return to_add, bonus


def tapped_land_penalty(tline: str, text_field: str) -> tuple[int, int]:
	"""Classify a land for tapped optimization.

	Returns (tapped_flag, penalty). tapped_flag is 1 if the land counts toward
	the tapped threshold. Penalty is higher for worse (slower) lands. Non-tapped
	lands return (0, 0).
	"""
	tline_l = tline.lower()
	text_l = text_field.lower()
	if 'land' not in tline_l:
		return 0, 0
	always_tapped = 'enters the battlefield tapped' in text_l
	shock_like = 'you may pay 2 life' in text_l  # shocks can be untapped
	conditional = any(kw in text_l for kw in ['unless you control', 'if you control', 'as long as you control']) or shock_like
	tapped_flag = 0
	if always_tapped and not shock_like:
		tapped_flag = 1
	elif conditional:
		tapped_flag = 1
	if not tapped_flag:
		return 0, 0
	tri_types = sum(1 for b in bc.BASIC_LAND_TYPE_KEYWORDS if b in tline_l) >= 3
	any_color = any(p in text_l for p in bc.ANY_COLOR_MANA_PHRASES)
	cycling = 'cycling' in text_l
	life_gain = 'gain' in text_l and 'life' in text_l and 'you gain' in text_l
	produces_basic_colors = any(sym in text_l for sym in bc.COLORED_MANA_SYMBOLS)
	penalty = 8 if always_tapped and not conditional else 6
	if tri_types:
		penalty -= 3
	if any_color:
		penalty -= 3
	if cycling:
		penalty -= 2
	if conditional:
		penalty -= 2
	if not produces_basic_colors and not any_color:
		penalty += 1
	if life_gain:
		penalty += 1
	return tapped_flag, penalty


def replacement_land_score(name: str, tline: str, text_field: str) -> int:
	"""Heuristic scoring of candidate replacement lands (higher is better)."""
	tline_l = tline.lower()
	text_l = text_field.lower()
	score = 0
	lname = name.lower()
	# Prioritize shocks explicitly
	if any(kw in lname for kw in ['blood crypt', 'steam vents', 'watery grave', 'breeding pool', 'godless shrine', 'hallowed fountain', 'overgrown tomb', 'stomping ground', 'temple garden', 'sacred foundry']):
		score += 20
	if 'you may pay 2 life' in text_l:
		score += 15
	if any(p in text_l for p in bc.ANY_COLOR_MANA_PHRASES):
		score += 10
	types_present = [b for b in bc.BASIC_LAND_TYPE_KEYWORDS if b in tline_l]
	score += len(types_present) * 3
	if 'unless you control' in text_l:
		score += 2
	if 'cycling' in text_l:
		score += 1
	return score


def is_color_fixing_land(tline: str, text_lower: str) -> bool:
	"""Heuristic to detect if a land significantly fixes colors.

	Criteria:
	  - Two or more basic land types
	  - Produces any color (explicit text)
	  - Text shows two or more distinct colored mana symbols
	"""
	basic_count = sum(1 for bk in bc.BASIC_LAND_TYPE_KEYWORDS if bk in tline.lower())
	if basic_count >= 2:
		return True
	if any(p in text_lower for p in bc.ANY_COLOR_MANA_PHRASES):
		return True
	distinct = {cw for cw in bc.COLORED_MANA_SYMBOLS if cw in text_lower}
	return len(distinct) >= 2


# ---------------------------------------------------------------------------
# Weighted sampling & fetch helpers
# ---------------------------------------------------------------------------
def weighted_sample_without_replacement(pool: list[tuple[str, int | float]], k: int, rng=None) -> list[str]:
	"""Sample up to k unique names from (name, weight) pool without replacement.

	If total weight becomes 0, stops early. Stable for small pools used here.
	"""
	if k <= 0 or not pool:
		return []
	# _rand imported at module level
	local_rng = rng if rng is not None else _rand
	working = pool.copy()
	chosen: list[str] = []
	while working and len(chosen) < k:
		total_w = sum(max(0, float(w)) for _, w in working)
		if total_w <= 0:
			break
		r = local_rng.random() * total_w
		acc = 0.0
		pick_idx = 0
		for idx, (nm, w) in enumerate(working):
			acc += max(0, float(w))
			if r <= acc:
				pick_idx = idx
				break
		nm, _w = working.pop(pick_idx)
		chosen.append(nm)
	return chosen


def count_existing_fetches(card_library: dict) -> int:
	bc = __import__('deck_builder.builder_constants', fromlist=['FETCH_LAND_MAX_CAP'])
	total = 0
	generic = getattr(bc, 'GENERIC_FETCH_LANDS', [])
	for n in generic:
		if n in card_library:
			total += card_library[n].get('Count', 1)
	for seq in getattr(bc, 'COLOR_TO_FETCH_LANDS', {}).values():
		for n in seq:
			if n in card_library:
				total += card_library[n].get('Count', 1)
	return total


def select_top_land_candidates(df, already: set[str], basics: set[str], top_n: int) -> list[tuple[int,str,str,str]]:
	"""Return list of (edh_rank, name, type_line, text_lower) for top_n remaining lands.

	Falls back to large rank number if edhrecRank missing/unparseable.
	"""
	out: list[tuple[int,str,str,str]] = []
	if df is None or getattr(df, 'empty', True):
		return out
	for _, row in df.iterrows():  # type: ignore[attr-defined]
		try:
			name = str(row.get('name',''))
			if not name or name in already or name in basics:
				continue
			tline = str(row.get('type', row.get('type_line','')))
			if 'land' not in tline.lower():
				continue
			edh = row.get('edhrecRank') if 'edhrecRank' in df.columns else None
			try:
				edh_val = int(edh) if edh not in (None,'','nan') else 999999
			except Exception:
				edh_val = 999999
			text_lower = str(row.get('text', row.get('oracleText',''))).lower()
			out.append((edh_val, name, tline, text_lower))
		except Exception:
			continue
	out.sort(key=lambda x: x[0])
	return out[:top_n]


# ---------------------------------------------------------------------------
# Generic DataFrame helpers (tag normalization & sorting)
# ---------------------------------------------------------------------------
def normalize_tag_cell(cell):
	"""Normalize a themeTags-like cell into a lowercase list of tags.

	Accepts list, nested list, or string forms. Mirrors logic previously in multiple
	methods inside builder.py.
	"""
	if isinstance(cell, list):
		out: list[str] = []
		for v in cell:
			if isinstance(v, list):
				out.extend(str(x).strip().lower() for x in v if str(x).strip())
			else:
				vs = str(v).strip().lower()
				if vs:
					out.append(vs)
		return out
	if isinstance(cell, str):
		raw = cell.lower()
		for ch in '[]"':
			raw = raw.replace(ch, ' ')
		parts = [p.strip().strip("'\"") for p in raw.replace(';', ',').split(',') if p.strip()]
		return [p for p in parts if p]
	return []


def sort_by_priority(df, columns: list[str]):
	"""Sort DataFrame by listed columns ascending if present; ignores missing.

	Returns new DataFrame (does not mutate original)."""
	present = [c for c in columns if c in df.columns]
	if not present:
		return df
	return df.sort_values(by=present, ascending=[True]*len(present), na_position='last')


def prefer_owned_first(df, owned_names_lower: set[str], name_col: str = 'name'):
	"""Stable-reorder DataFrame to put owned names first while preserving prior sort.

	- Adds a temporary column to flag ownership, sorts by it desc with mergesort, then drops it.
	- If the name column is missing or owned_names_lower empty, returns df unchanged.
	"""
	try:
		if df is None or getattr(df, 'empty', True):
			return df
		if not owned_names_lower:
			return df
		if name_col not in df.columns:
			return df
		tmp_col = '_ownedPref'
		# Avoid clobbering if already present
		while tmp_col in df.columns:
			tmp_col = tmp_col + '_x'
		ser = df[name_col].astype(str).str.lower().isin(owned_names_lower).astype(int)
		df = df.assign(**{tmp_col: ser})
		df = df.sort_values(by=[tmp_col], ascending=[False], kind='mergesort')
		df = df.drop(columns=[tmp_col])
		return df
	except Exception:
		return df


# ---------------------------------------------------------------------------
# Tag-driven land suggestion helpers
# ---------------------------------------------------------------------------
def build_tag_driven_suggestions(builder) -> list[dict]:  # type: ignore[override]
	"""Return a list of suggestion dicts based on selected commander tags.

	Each dict fields:
	  name, reason, condition (callable taking builder), flex (bool), defer_if_full (bool)
	"""
	tags_lower = [t.lower() for t in getattr(builder, 'selected_tags', [])]
	existing = set(builder.card_library.keys())
	suggestions: list[dict] = []

	def cond_always(_):
		return True

	def cond_artifact_threshold(b):
		art_count = sum(1 for v in b.card_library.values() if 'artifact' in str(v.get('Card Type', '')).lower())
		return art_count >= 10

	mapping = [
		(['+1/+1 counters', 'counters matter'], 'Gavony Township', cond_always, '+1/+1 Counters support', True),
		(['token', 'tokens', 'wide'], 'Castle Ardenvale', cond_always, 'Token strategy support', True),
		(['graveyard', 'recursion', 'reanimator'], 'Boseiju, Who Endures', cond_always, 'Graveyard interaction / utility', False),
		(['graveyard', 'recursion', 'reanimator'], 'Takenuma, Abandoned Mire', cond_always, 'Recursion utility', True),
		(['artifact'], "Inventors' Fair", cond_artifact_threshold, 'Artifact payoff (conditional)', True),
	]
	for tag_keys, land_name, condition, reason, flex in mapping:
		if any(k in tl for k in tag_keys for tl in tags_lower):
			if land_name not in existing:
				suggestions.append({
					'name': land_name,
					'reason': reason,
					'condition': condition,
					'flex': flex,
					'defer_if_full': True
				})
	# Landfall fetch cap soft bump (side-effect set on builder)
	if any('landfall' in tl for tl in tags_lower) and not hasattr(builder, '_landfall_fetch_bump_applied'):
		setattr(builder, '_landfall_fetch_bump_applied', True)
		builder.dynamic_fetch_cap = getattr(__import__('deck_builder.builder_constants', fromlist=['FETCH_LAND_MAX_CAP']), 'FETCH_LAND_MAX_CAP', 7) + 1  # safe fallback
	return suggestions


# ---------------------------------------------------------------------------
# Color balance swap helpers
# ---------------------------------------------------------------------------
def select_color_balance_removal(builder, deficit_colors: set[str], overages: dict[str, float]) -> str | None:
	"""Select a land to remove when performing color balance swaps.

	Preference order:
	  1. Flex lands not producing any deficit colors
	  2. Basic land of the most overrepresented color
	  3. Mono-color non-flex land not producing deficit colors
	"""
	matrix_current = builder._compute_color_source_matrix()
	land_names = set(matrix_current.keys())  # ensure we only ever remove lands
	# Flex lands first
	for name, entry in builder.card_library.items():
		if name not in land_names:
			continue
		if entry.get('Role') == 'flex':
			colors = matrix_current.get(name, {})
			if not any(colors.get(c, 0) for c in deficit_colors):
				return name
	# Basic of most overrepresented color
	if overages:
		color_remove = max(overages.items(), key=lambda x: x[1])[0]
		basic_map = {'W': 'Plains', 'U': 'Island', 'B': 'Swamp', 'R': 'Mountain', 'G': 'Forest'}
		candidate = basic_map.get(color_remove)
		if candidate and candidate in builder.card_library and candidate in land_names:
			return candidate
	# Mono-color non-flex lands
	for name, entry in builder.card_library.items():
		if name not in land_names:
			continue
		if entry.get('Role') == 'flex':
			continue
		colors = matrix_current.get(name, {})
		color_count = sum(1 for v in colors.values() if v)
		if color_count <= 1 and not any(colors.get(c, 0) for c in deficit_colors):
			return name
	return None


def color_balance_addition_candidates(builder, target_color: str, combined_df) -> list[str]:
	"""Rank potential addition lands for a target color (best first)."""
	if combined_df is None or getattr(combined_df, 'empty', True):
		return []
	existing = set(builder.card_library.keys())
	out: list[tuple[str, int]] = []
	for _, row in combined_df.iterrows():  # type: ignore[attr-defined]
		name = str(row.get('name', ''))
		if not name or name in existing or any(name == o[0] for o in out):
			continue
		tline = str(row.get('type', row.get('type_line', ''))).lower()
		if 'land' not in tline:
			continue
		text_field = str(row.get('text', row.get('oracleText', ''))).lower()
		produces = False
		if target_color == 'W' and ('plains' in tline or '{w}' in text_field):
			produces = True
		if target_color == 'U' and ('island' in tline or '{u}' in text_field):
			produces = True
		if target_color == 'B' and ('swamp' in tline or '{b}' in text_field):
			produces = True
		if target_color == 'R' and ('mountain' in tline or '{r}' in text_field):
			produces = True
		if target_color == 'G' and ('forest' in tline or '{g}' in text_field):
			produces = True
		if not produces:
			continue
		any_color = 'add one mana of any color' in text_field
		basic_types = sum(1 for b in bc.BASIC_LAND_TYPE_KEYWORDS if b in tline)
		score = 0
		if any_color:
			score += 30
		score += basic_types * 10
		if 'enters the battlefield tapped' in text_field and 'you may pay 2 life' not in text_field:
			score -= 5
		out.append((name, score))
	out.sort(key=lambda x: x[1], reverse=True)
	return [n for n, _ in out]


# ---------------------------------------------------------------------------
# Basic land / land cap helpers
# ---------------------------------------------------------------------------
def basic_land_names() -> set[str]:
	names = set(getattr(__import__('deck_builder.builder_constants', fromlist=['BASIC_LANDS']), 'BASIC_LANDS', []))
	names.update(getattr(__import__('deck_builder.builder_constants', fromlist=['SNOW_BASIC_LAND_MAPPING']), 'SNOW_BASIC_LAND_MAPPING', {}).values())
	names.add('Wastes')
	return names


def count_basic_lands(card_library: dict) -> int:
	basics = basic_land_names()
	total = 0
	for name, entry in card_library.items():
		if name in basics:
			total += entry.get('Count', 1)
	return total


def choose_basic_to_trim(card_library: dict) -> str | None:
	basics = basic_land_names()
	candidates: list[tuple[int, str]] = []
	for name, entry in card_library.items():
		if name in basics:
			cnt = entry.get('Count', 1)
			if cnt > 0:
				candidates.append((cnt, name))
	if not candidates:
		return None
	candidates.sort(reverse=True)
	return candidates[0][1]


def enforce_land_cap(builder, step_label: str = ""):
	if not hasattr(builder, 'ideal_counts') or not getattr(builder, 'ideal_counts'):
		return
	bc = __import__('deck_builder.builder_constants', fromlist=['DEFAULT_LAND_COUNT'])
	land_target = builder.ideal_counts.get('lands', getattr(bc, 'DEFAULT_LAND_COUNT', 35))
	min_basic = builder.ideal_counts.get('basic_lands', getattr(bc, 'DEFAULT_BASIC_LAND_COUNT', 20))
	# math not needed; using ceil via BASIC_FLOOR_FACTOR logic only
	floor_basics = math.ceil(bc.BASIC_FLOOR_FACTOR * min_basic)
	current_land = builder._current_land_count()
	if current_land <= land_target:
		return
	builder.output_func(f"\nLand Cap Enforcement after {step_label}: Over target ({current_land}/{land_target}). Trimming basics...")
	removed = 0
	while current_land > land_target:
		basic_total = count_basic_lands(builder.card_library)
		if basic_total <= floor_basics:
			builder.output_func(f"Stopped trimming: basic lands at floor {basic_total} (floor {floor_basics}). Still {current_land}/{land_target}.")
			break
		target_basic = choose_basic_to_trim(builder.card_library)
		if not target_basic or not builder._decrement_card(target_basic):
			builder.output_func("No basic lands available to trim further.")
			break
		removed += 1
		current_land = builder._current_land_count()
	if removed:
		builder.output_func(f"Trimmed {removed} basic land(s). New land count: {current_land}/{land_target}. Basic total now {count_basic_lands(builder.card_library)} (floor {floor_basics}).")