#!/usr/bin/env python3
"""Resolve Nextcloud view rows through explicitly configured storage mounts."""

from __future__ import annotations

import argparse
import csv
import json
import os
import re
import subprocess
import sys
import tempfile
from pathlib import Path, PurePosixPath

IDENTIFIER = re.compile(r"^[A-Za-z_][A-Za-z0-9_]*(?:\.[A-Za-z_][A-Za-z0-9_]*)?$")


def validate_view(name: str) -> str:
    value = str(name).strip()
    if not IDENTIFIER.fullmatch(value):
        raise ValueError(f"invalid SQL view name: {value!r}")
    return value


def read_config(path: Path) -> dict[str, list[tuple[str, Path, str]]]:
    result: dict[str, list[tuple[str, Path, str]]] = {}
    with path.open(encoding="utf-8") as handle:
        for number, line in enumerate(handle, 1):
            line=line.rstrip("\n")
            if not line or line.startswith("#"):continue
            fields=line.split("\t")
            if len(fields) not in {3,4}:raise ValueError(f"{path}:{number}: expected storage_id, source_prefix, local_mount and optional include_prefix")
            storage_id,prefix,mount=fields[:3]
            include_prefix=fields[3] if len(fields)==4 else ""
            storage_id=storage_id.strip();prefix=prefix.strip("/");include_prefix=include_prefix.strip("/")
            if not storage_id:raise ValueError(f"{path}:{number}: storage_id is empty")
            if ".." in PurePosixPath(prefix).parts or ".." in PurePosixPath(include_prefix).parts:raise ValueError(f"{path}:{number}: unsafe prefix")
            result.setdefault(storage_id,[]).append((prefix,Path(mount),include_prefix))
    return result


def run_query(args: argparse.Namespace, env: dict[str,str], sql: str) -> subprocess.CompletedProcess[str]:
    command=["psql","-X","-A","-F","\t","-t","-v","ON_ERROR_STOP=1","-h",args.host,"-p",str(args.port),"-U",args.user,"-d",args.database,"-c",sql]
    return subprocess.run(command,env=env,check=False,text=True,capture_output=True)


def query_rows(args: argparse.Namespace) -> list[list[str]]:
    password=args.password_file.read_text(encoding="utf-8").strip();env=os.environ.copy();env["PGPASSWORD"]=password;view=validate_view(args.view)
    modern_sql=f"SELECT share_id, item_type, display_name, storage_id, source_path FROM {view} ORDER BY share_id"
    completed=run_query(args,env,modern_sql)
    if completed.returncode==0:return list(csv.reader(completed.stdout.splitlines(),delimiter="\t"))
    if "item_type" not in completed.stderr or "does not exist" not in completed.stderr:raise RuntimeError(completed.stderr.strip() or "Nextcloud source view query failed")
    legacy_sql=f"SELECT share_id, display_name, storage_id, source_path FROM {view} ORDER BY share_id"
    completed=run_query(args,env,legacy_sql)
    if completed.returncode!=0:raise RuntimeError(completed.stderr.strip() or "legacy Nextcloud source view query failed")
    rows=[]
    for row in csv.reader(completed.stdout.splitlines(),delimiter="\t"):
        if len(row)==4:
            share_id,display_name,storage_id,source_path=row;rows.append([share_id,"",display_name,storage_id,source_path])
        else:rows.append(row)
    return rows


def contained_join(root: Path, relative: str) -> Path:
    parts=PurePosixPath(relative).parts
    if relative.startswith("/") or ".." in parts:raise ValueError(f"unsafe source path: {relative}")
    return root.joinpath(*parts)


def matches_prefix(path: str, prefix: str) -> bool:
    if not prefix:return True
    return path==prefix or path.startswith(prefix+"/")


def resolve_adapter(adapters: dict[str,list[tuple[str,Path,str]]],storage_id: str,source_path: str) -> tuple[str,Path,str] | None:
    relative=source_path.strip("/")
    matches=[]
    for prefix,mount,include_prefix in adapters.get(storage_id,[]):
        if not matches_prefix(relative,prefix):continue
        mapped_relative=relative[len(prefix):].lstrip("/") if prefix else relative
        if not matches_prefix(mapped_relative,include_prefix):continue
        matches.append((prefix,mount,include_prefix))
    if not matches:return None
    matches.sort(key=lambda item:(len(item[0]),len(item[2])),reverse=True)
    return matches[0]


def build(args: argparse.Namespace) -> dict[str,object]:
    validate_view(args.view);adapters=read_config(args.storage_config);rows=query_rows(args)
    if not rows and not args.allow_empty:raise RuntimeError("Nextcloud returned no Showcase shares; refusing an empty manifest")
    manifest=[];errors=[];folder_count=0;file_count=0
    for row in rows:
        if len(row)!=5:errors.append(f"invalid database row with {len(row)} columns");continue
        share_id,item_type,display_name,storage_id,source_path=row;item_type=item_type.strip().lower();relative=source_path.strip("/")
        if item_type and item_type not in {"folder","file"}:errors.append(f"share {share_id}: unsupported item_type {item_type!r}");continue
        adapter=resolve_adapter(adapters,storage_id,relative)
        if not adapter:continue
        prefix,mount,_include_prefix=adapter
        if prefix:relative=relative[len(prefix):].lstrip("/")
        source=contained_join(mount,relative)
        if not mount.is_mount():errors.append(f"share {share_id}: storage mount unavailable: {mount}");continue
        if not item_type:
            if source.is_dir():item_type="folder"
            elif source.is_file():item_type="file"
            else:errors.append(f"share {share_id}: source unavailable: {source}");continue
        if item_type=="folder":
            if not source.is_dir():errors.append(f"share {share_id}: source directory unavailable: {source}");continue
            folder_count+=1
        else:
            if not source.is_file():errors.append(f"share {share_id}: source file unavailable: {source}");continue
            file_count+=1
        if "\t" in display_name or "\n" in display_name or "\r" in display_name:errors.append(f"share {share_id}: display name contains unsupported control characters");continue
        source_text=str(source)
        if "\t" in source_text or "\n" in source_text or "\r" in source_text:errors.append(f"share {share_id}: source path contains unsupported control characters");continue
        manifest.append(f"{share_id}\t{item_type}\t{display_name.lstrip('/')}\t{source}")
    if errors:raise RuntimeError("; ".join(errors))
    if not manifest and rows and not args.allow_empty:raise RuntimeError("no Showcase shares match the selected directories")
    args.output.parent.mkdir(parents=True,exist_ok=True)
    with tempfile.NamedTemporaryFile("w",encoding="utf-8",dir=args.output.parent,delete=False) as handle:
        handle.write("\n".join(manifest)+("\n" if manifest else ""));temporary=Path(handle.name)
    temporary.replace(args.output)
    return {"shares":len(manifest),"folders":folder_count,"files":file_count,"manifest":str(args.output)}


def main() -> int:
    parser=argparse.ArgumentParser();parser.add_argument("--host",required=True);parser.add_argument("--port",type=int,default=5432);parser.add_argument("--database",required=True);parser.add_argument("--user",required=True);parser.add_argument("--password-file",required=True,type=Path);parser.add_argument("--view",default="piwigo_showcase_sources");parser.add_argument("--storage-config",required=True,type=Path);parser.add_argument("--output",required=True,type=Path);parser.add_argument("--allow-empty",action="store_true");args=parser.parse_args()
    try:print(json.dumps(build(args),ensure_ascii=False))
    except Exception as error:print(f"manifest: {error}",file=sys.stderr);return 1
    return 0


if __name__=="__main__":raise SystemExit(main())