import builtins
import json
import keyword
import math
import re
from datetime import datetime  # noqa
from pathlib import Path
from textwrap import indent
from typing import List
from typing import Optional, Callable, Tuple
from typing import Union, Dict, Any

import numpy as np
import pandas as pd
import rasterio
from pyproj import Geod
from pyproj import Transformer
from rasterio.transform import Affine
from tqdm import tqdm


def _nan_to_none(obj):
    if isinstance(obj, dict):
        return {k: _nan_to_none(v) for k, v in obj.items()}
    elif isinstance(obj, list):
        return [_nan_to_none(v) for v in obj]
    elif isinstance(obj, float) and math.isnan(obj):
        return None
    else:
        return obj


def resolve_code(code: Any,
                 codebook: Union[str, Dict[str, Any]],
                 top_key: str = None,
                 ignore_error_codes=None) -> Optional[str]:
    """
    Resolve a hierarchical code into its labels by prefix-walking the code.

    - If code is in ignore_error_codes or empty -> return None silently.
    - If code not found in codebook and not ignored -> raise KeyError.
    - top_key missing is a hard error (still raises).
    """
    # normalize ignore list
    ignore_error_codes = [] if ignore_error_codes is None else list(ignore_error_codes)

    # accept non-str inputs; only None/empty-string -> None
    if code is None or (isinstance(code, str) and not code.strip()):
        return None

    # normalize code to string; "3.0" -> "3"
    code_str = str(code).strip()
    try:
        f = float(code_str)
        if f.is_integer():
            code_str = str(int(f))
    except Exception:
        # keep original string if not a number
        pass

    # fast path: ignored codes
    if code_str in ignore_error_codes:
        return None

    # Load codebook
    if isinstance(codebook, str):
        try:
            with open("src/fuse_esdac/codebooks/" + codebook + ".json", "r", encoding="utf-8") as fs:
                codebook_dict = json.load(fs)
        except FileNotFoundError as e:
            raise FileNotFoundError(f"Codebook file not found: {codebook}") from e
        except json.JSONDecodeError as e:
            raise ValueError(f"Invalid JSON in codebook file: {codebook}") from e
    elif isinstance(codebook, dict):
        codebook_dict = codebook
    else:
        raise TypeError(f"codebook must be a file path (str) or dict, got {type(codebook).__name__}")

    # Pick source dict (top_key remains strict)
    src = codebook_dict if top_key is None else codebook_dict.get(top_key)
    if src is None:
        raise KeyError(f"top_key '{top_key}' not found in codebook")
    if not isinstance(src, dict):
        raise TypeError(f"Top-level codebook section must be a dict, got {type(src).__name__}")

    labels: List[str] = []
    level_dict = src

    # progressive prefixes
    prefixes = [code_str[:i] for i in range(1, len(code_str) + 1)]

    for pref in prefixes:
        if not isinstance(level_dict, dict):
            raise ValueError(f"Invalid structure: expected dict at prefix '{pref}', got {type(level_dict).__name__}")

        if pref not in level_dict:
            break

        node = level_dict[pref]

        if isinstance(node, dict):
            if "value" not in node:
                raise KeyError(f"Missing 'value' key in node for prefix '{pref}'")
            if "children" not in node:
                raise KeyError(f"Missing 'children' key in node for prefix '{pref}'")
            if not isinstance(node["value"], str):
                raise TypeError(f"'value' for prefix '{pref}' must be a string, got {type(node['value']).__name__}")
            if not isinstance(node["children"], dict):
                raise TypeError(f"'children' for prefix '{pref}' must be a dict, got {type(node['children']).__name__}")

            labels.append(node["value"])
            level_dict = node["children"]

        elif isinstance(node, str):
            if not node.strip():
                raise ValueError(f"Empty string label for prefix '{pref}'")
            labels.append(node)
            break  # leaf node, stop walking

        else:
            raise TypeError(f"Unexpected node type for prefix '{pref}': {type(node).__name__}")

    # post-check: no match -> ignore or raise
    if len(labels) == 0:
        if code_str in ignore_error_codes:
            return None
        raise KeyError(f"Code '{code_str}' not found in codebook")

    return code_str + ": " + " => ".join(labels)


def as_float(number: Any, keep_str=True, ignore_substr="-999", factor=1.0) -> Optional[float]:
    """Convert to float; empty CSV values -> None; real errors -> raise."""
    if number is None or (isinstance(number, str) and number.strip() == ""):
        return None
    if ignore_substr is not None and ignore_substr in number:
        return None
    try:
        return float(number) * factor
    except (ValueError, TypeError) as e:
        if keep_str:
            return number.strip()
        raise ValueError(f"as_float: cannot convert {number!r}") from e


def as_int_id(number: Any, allow_letters: bool = False) -> Optional[str]:
    """
    Convert to integer-like string.
    If allow_letters is True, allow prefix/suffix letters around digits (e.g., 'AA024322BB'),
    but reject strings with interleaved letters (e.g., 'A2323B232C').
    """
    if number is None:
        raise ValueError("as_int_id: input is None")

    s = str(number).strip()

    if not allow_letters:
        try:
            return str(int(float(s)))
        except (ValueError, TypeError) as e:
            raise ValueError(f"as_int_id: cannot convert {number!r}") from e
    else:
        # Allow only prefix/suffix letters, core must be digits
        m = re.fullmatch(r"[A-Za-z]*([0-9]+)[A-Za-z]*", s)
        if not m:
            raise ValueError(f"as_int_id: invalid alphanumeric format {number!r}")
        return m.group(1)


def _sanitize_identifier(name: str, used: set) -> str:
    """Convert arbitrary string to a unique, valid Python identifier."""
    # Replace non-identifier chars with underscores and strip leading/trailing underscores
    ident = re.sub(r'\W+', '_', str(name)).strip('_')

    # Empty or starts with digit -> prefix with underscore
    if not ident or ident[0].isdigit():
        ident = f"_{ident}" if ident else "_arg"

    # Avoid keywords and builtins
    if keyword.iskeyword(ident) or ident in dir(builtins):
        ident += "_"

    # Ensure uniqueness
    base = ident
    i = 1
    while ident in used:
        ident = f"{base}_{i}"
        i += 1

    used.add(ident)
    return ident


def make_callable(expr: str, returns_str: bool = False) -> Union[Callable, Tuple[Callable, str]]:
    """
    Compile an expression string with placeholders into a callable.

    Placeholders of the form 【name】 are replaced by valid Python parameter names,
    preserving order and uniqueness. A mapping from safe names to original placeholders
    is attached to the returned function as `_arg_map` and `_arg_order`.

    Args:
        expr: Expression string containing placeholders.
        returns_str: If True, return (callable, function_definition_str); otherwise return callable.

    Returns:
        Callable or (Callable, str): The compiled function, and optionally the source code.
    """
    # find placeholders
    orig_vars = re.findall(r'【(.*?)】', expr)
    orig_vars = list(dict.fromkeys(orig_vars))  # dedupe preserving order

    # build safe arg names + mapping
    used = set()
    safe_args = []
    arg_map = {}
    for v in orig_vars:
        s = _sanitize_identifier(v, used)
        safe_args.append(s)
        arg_map[s] = v

    # replace placeholders in expression with safe arg names
    body_expr = expr
    for s in safe_args:
        orig = arg_map[s]
        body_expr = body_expr.replace(f"【{orig}】", s)

    # define function text
    args_str = ", ".join(safe_args)
    func_str = f"def func({args_str}):\n"
    func_str += indent(f"return {body_expr}", "    ")

    # exec in isolated globals that still see current globals
    exec_globals = globals().copy()
    local_vars = {}
    exec(func_str, exec_globals, local_vars)
    fn = local_vars["func"]

    # attach mapping for callers
    setattr(fn, "_arg_map", arg_map)  # safe -> original
    setattr(fn, "_arg_order", tuple(safe_args))  # ordered safe args

    if returns_str:
        return fn, func_str
    return fn


def _eval_expr(expr: str, row: Dict[str, Any]) -> Any:
    """
    Evaluate a schema expression against a CSV row.
    - If any referenced CSV value is empty/None -> return None (no noise).
    - Otherwise: print detailed error and return None.
    """
    if expr is None:
        return None
    try:
        fn, func_src = make_callable(expr, returns_str=True)
        kwargs = {}
        had_empty_input = False
        for safe in getattr(fn, "_arg_order", []):
            orig = fn._arg_map[safe]
            raw = row.get(orig, None)
            # normalize to str or None; treat "" as empty
            if raw is None:
                had_empty_input = True
                kwargs[safe] = None
            else:
                s = str(raw)
                if s == "":
                    had_empty_input = True
                    kwargs[safe] = None
                else:
                    kwargs[safe] = s
        return fn(**kwargs)
    except Exception as e:
        if 'had_empty_input' in locals() and had_empty_input:
            return None
        print("=== EVAL ERROR ===")
        print("expr:", expr)
        try:
            print("compiled:\n", func_src)
        except Exception:
            pass
        try:
            print("kwargs:", kwargs)
        except Exception:
            pass
        print("error:", repr(e))
        print("==================")
        return None


def _labels_to_list(s: Optional[str]) -> list:
    if not isinstance(s, str):
        return []
    parts = [p.strip() for p in s.split(",")]
    return [p for p in parts if p]


def fuse_csv(
        source_file: Union[str, Path],
        schema: Dict[str, Any],
        source_name: str,
        current_dict: Dict[str, Any],
) -> Dict[str, Any]:
    """
    Fuse CSV rows into hierarchical dict.

    New convention:
    - Thematic sections map var_name -> expression directly.
    - Units parsed from "(...)" in var_name.
    - SHARED merged into every variable.
    - ENTRY_KEY handling:
        * If ENTRY_KEY starts with '^', treat as regex to match existing keys (never create new).
        * Otherwise, treat as literal key (create new if not present).
    """
    df = pd.read_csv(source_file, dtype=str, keep_default_na=False, na_values=[])
    out_dict = dict(current_dict) if current_dict else {}

    CONTROL_KEYS = {"ENTRY_KEY", "LAT_LONG", "COUNTRY_CODE", "SAMPLE_DATE", "SAMPLE_DEPTH_RANGE_CM", "SHARED"}
    thematic_keys = [k for k in schema.keys() if k not in CONTROL_KEYS]

    filename_for_bar = Path(source_file).name if isinstance(source_file, (str, Path)) else str(source_file)
    for _, row in tqdm(df.iterrows(), total=len(df), desc=filename_for_bar):
        row_dict = row.to_dict()
        entry_key_expr = schema.get("ENTRY_KEY")
        entry_key_val = _eval_expr(entry_key_expr, row_dict)
        if entry_key_val in (None, ""):
            continue

        lat_long = _eval_expr(schema.get("LAT_LONG"), row_dict)
        country_code = _eval_expr(schema.get("COUNTRY_CODE"), row_dict)
        sample_date = _eval_expr(schema.get("SAMPLE_DATE"), row_dict)
        sample_depth_range_cm = _eval_expr(schema.get("SAMPLE_DEPTH_RANGE_CM"), row_dict)

        # Shared metadata
        shared_evaluated = {sk: _eval_expr(sv, row_dict)
                            for sk, sv in (schema.get("SHARED", {}) or {}).items()}
        shared_evaluated["source_dataset"] = source_name
        if "distance_to_grid (m)" not in shared_evaluated:
            shared_evaluated["distance_to_grid (m)"] = 0.0

        # Step 1. Resolve target entries
        if str(entry_key_val).startswith("^"):  # regex matching
            pattern = re.compile(str(entry_key_val))
            targets = [k for k in out_dict.keys() if pattern.search(k)]
            is_new_sample = False
            # never create new
        else:  # exact match
            if lat_long is None:
                continue
            if lat_long[0] is None or lat_long[1] is None:
                continue
            if entry_key_val not in out_dict:
                out_dict[entry_key_val] = {}
            targets = [entry_key_val]
            is_new_sample = True

        # Step 2. Apply update
        for key in targets:
            sample = out_dict[key]
            if is_new_sample:
                assert lat_long is not None
                sample["LAT_LONG"] = lat_long
                assert country_code is not None
                sample["COUNTRY_CODE"] = country_code
                assert sample_date is not None
                sample["SAMPLE_DATE"] = sample_date
                assert sample_depth_range_cm is not None
                sample["SAMPLE_DEPTH_RANGE_CM"] = sample_depth_range_cm
                assert source_name is not None
                sample["SAMPLE_SOURCE_DATASET"] = source_name

            for sec_name in thematic_keys:
                sec_schema = schema.get(sec_name, {}) or {}
                section_data = {}

                for var_name, expr in sec_schema.items():
                    value = _eval_expr(expr, row_dict)

                    m = re.match(r"^([^\s()]+)\s*\((.+)\)\s*$", var_name)
                    if m:
                        clean_name = m.group(1).strip()
                        unit = m.group(2).strip()
                    else:
                        clean_name, unit = var_name.strip(), None

                    leaf = {"value": value}
                    if unit:
                        leaf["unit"] = unit
                    leaf.update(shared_evaluated)

                    section_data[clean_name] = leaf

                existing_section = sample.get(sec_name, {})
                merged_section = dict(existing_section)
                for var_name, leaf in section_data.items():
                    if var_name not in merged_section:
                        merged_section[var_name] = leaf  # only add if missing
                sample[sec_name] = merged_section

    return out_dict


def fuse_tif(
        source_file: Union[str, Path],
        schema: Dict[str, Any],
        source_name: str,
        current_dict: Dict[str, Any],
) -> Dict[str, Any]:
    out_dict = dict(current_dict) if current_dict else {}

    CONTROL_KEYS = {"CRS_STRING"}
    thematic_keys = [k for k in schema.keys() if k not in CONTROL_KEYS]

    keys, lats, lons = [], [], []
    for k, s in out_dict.items():
        if "LAT_LONG" in s and s["LAT_LONG"] not in (None, "", "null"):
            lat, lon = s["LAT_LONG"]
            keys.append(k)
            lats.append(lat)
            lons.append(lon)

    if not keys:
        return out_dict

    keys = np.array(keys)
    lats = np.array(lats, dtype=float)
    lons = np.array(lons, dtype=float)

    tif_dir = Path(source_file)
    geod = Geod(ellps="WGS84")

    def _sample_one_entry(tif_entry):
        value_map = None
        scale_factor = 1.0

        if isinstance(tif_entry, list):
            if len(tif_entry) == 2:
                if isinstance(tif_entry[1], dict):
                    tif_key, value_map = tif_entry
                elif isinstance(tif_entry[1], (int, float)):
                    tif_key, scale_factor = tif_entry
                else:
                    raise ValueError(
                        f"Error parsing entry {tif_entry}: second item must be a dict (codebook) or a number (scale factor)"
                    )
            elif len(tif_entry) == 1 and isinstance(tif_entry[0], str):
                # simple single-item list, same as plain string
                tif_key = tif_entry[0]
            else:
                # multi-entry list → likely a profile list, handle outside
                raise ValueError(
                    f"Error parsing entry {tif_entry}: unexpected list form (did you mean a profile list?)"
                )
        else:
            tif_key = tif_entry

        tif_path = tif_dir / f"{tif_key}.standardized.tif"
        with rasterio.open(tif_path) as ds:
            arr = ds.read(1)
            nodata = ds.nodata
            inv_affine: Affine = ~ds.transform
            if "CRS_STRING" in schema:
                crs = rasterio.crs.CRS.from_string(schema["CRS_STRING"])
            else:
                crs = ds.crs
                if crs is None or "LOCAL_CS" in crs.to_wkt():
                    raise ValueError(f"{tif_key}.standardized.tif: CRS not available. Please provide CRS_STRING")
            transformer = Transformer.from_crs("EPSG:4326", crs, always_xy=True)

            xs, ys = transformer.transform(lons, lats)
            cols, rows = inv_affine * (xs, ys)
            rows = np.round(rows).astype(int)
            cols = np.round(cols).astype(int)

            in_bounds = (rows >= 0) & (rows < ds.height) & (cols >= 0) & (cols < ds.width)

            values = np.empty(len(keys), dtype=object)
            values[:] = np.nan
            dists = np.full(len(keys), np.nan, dtype=float)

            if np.any(in_bounds):
                r = rows[in_bounds]
                c = cols[in_bounds]

                raw_vals = arr[r, c]

                x_centers, y_centers = ds.transform * (c, r)
                lats_geo = lats[in_bounds]
                lons_geo = lons[in_bounds]

                if crs.is_geographic:
                    _, _, d_valid = geod.inv(lons_geo, lats_geo, x_centers, y_centers)
                else:
                    xs_valid = xs[in_bounds]
                    ys_valid = ys[in_bounds]
                    d_valid = np.sqrt((xs_valid - x_centers) ** 2 + (ys_valid - y_centers) ** 2)

                if nodata is not None:
                    nd_mask = np.isclose(raw_vals, nodata, equal_nan=True)
                else:
                    nd_mask = np.zeros_like(raw_vals, dtype=bool)

                out_vals = []
                for rv, is_nd in zip(raw_vals, nd_mask):
                    if is_nd:
                        out_vals.append(np.nan)
                    else:
                        if value_map is not None:
                            try:
                                code_str = str(int(round(float(rv))))
                            except Exception:
                                code_str = str(int(round(rv)))
                            out_vals.append(code_str + ": " + str(value_map.get(code_str, "Unknown")))
                        else:
                            out_vals.append(float(rv) * scale_factor)

                values[in_bounds] = out_vals
                d_valid = np.array(d_valid, dtype=float)
                d_valid[nd_mask] = np.nan
                dists[in_bounds] = d_valid

            return values, dists, in_bounds

    all_vars = []
    for sec_name in thematic_keys:
        for var_name, tif_entry in schema[sec_name].items():
            all_vars.append((sec_name, var_name, tif_entry))

    for sec_name, var_name, tif_entry in tqdm(all_vars, desc=f"Processing variables in {tif_dir.name}"):
        m = re.match(r"^(.*)\s+\(([^()]*)\)$", var_name)
        if m:
            clean_name, unit = m.group(1).strip(), m.group(2).strip()
        else:
            clean_name, unit = var_name.strip(), None

        is_profile = (
                isinstance(tif_entry, list)
                and not (
                len(tif_entry) == 2
                and isinstance(tif_entry[1], (dict, int, float))
        )
        )

        if is_profile:
            per_entry_values = []
            per_entry_dists = []
            union_in_bounds = np.zeros(len(keys), dtype=bool)

            for entry in tif_entry:
                vals, dists, in_bounds = _sample_one_entry(entry)
                per_entry_values.append(vals)
                per_entry_dists.append(dists)
                union_in_bounds |= in_bounds

            for idx, key in enumerate(keys):
                if not union_in_bounds[idx]:
                    continue

                sample = out_dict[key]
                section = sample.setdefault(sec_name, {})
                if clean_name in section:
                    continue

                value_list = [vals[idx] for vals in per_entry_values]

                dist_candidates = []
                for d in per_entry_dists:
                    di = d[idx]
                    if not (isinstance(di, float) and np.isnan(di)):
                        dist_candidates.append(float(di))
                dist_reduced = (max(dist_candidates) if dist_candidates else None)

                leaf = {
                    "value": value_list,
                    **({"unit": unit} if unit else {}),
                    "distance_to_grid (m)": dist_reduced,
                    "source_dataset": source_name
                }
                leaf = _nan_to_none(leaf)
                section[clean_name] = leaf

        else:
            vals, dists, in_bounds = _sample_one_entry(tif_entry)

            ib_idx = np.where(in_bounds)[0]
            for ii in ib_idx:
                key = keys[ii]
                sample = out_dict[key]
                section = sample.setdefault(sec_name, {})
                if clean_name in section:
                    continue

                raw_val = vals[ii]
                val = None if (isinstance(raw_val, float) and np.isnan(raw_val)) else raw_val
                dist_val = float(dists[ii]) if not np.isnan(dists[ii]) else np.nan

                leaf = {
                    "value": val,
                    **({"unit": unit} if unit else {}),
                    "distance_to_grid (m)": dist_val,
                    "source_dataset": source_name
                }
                leaf = _nan_to_none(leaf)
                section[clean_name] = leaf

    return out_dict