import os.path
import pydoc
from pathlib import Path
from typing import List, MutableMapping, Optional

from ee import EeException
from ee.db import ObjDb
from ee.part import PartDb, load_db, save_db, Part
from ee.project import Project, report, SupplierDescriptor
from ee.xml import types

__all__ = ["create_bom"]


class BomPart(object):
    def __init__(self, part: types.Part):
        self.part = Part(part)
        ref = self.part.get_only_schematic_reference()
        self.ref = ref.referenceProp if ref else None
        self.available_from: MutableMapping[str, Part] = {}
        self.selected_part = None


def make_report(out_file, unresolved_parts, bom_parts: ObjDb[BomPart], supplier_parts: ObjDb[Path]):
    kwargs = {
        "bom_parts": bom_parts,
        "supplier_parts": supplier_parts,
        "unresolved_parts": unresolved_parts,
    }
    report.save_report("ee", "bom.rst.j2", out_file, **kwargs)


def default_strategy(x):
    return x


def create_bom(project: Project, schematic_path: Path, out_path: Path, part_dbs: List[Path],
               fail_on_missing_parts: bool, strategy_name: Optional[str]):
    strategy = default_strategy
    if strategy_name:
        strategy = pydoc.locate(strategy_name)
        if not callable(strategy):
            raise EeException("Not a callable: {}, is a {}".format(strategy_name, type(strategy)))

    supplier_parts = ObjDb[Part]()
    supplier_parts.add_unique_index("uri", lambda p: p.uri)
    supplier_parts.add_index("spn", lambda p: [ref.valueProp for ref in p.get_spns()],
                             multiple=True)
    supplier_pn_idx = supplier_parts.add_multi_index("supplier,pn", lambda p: [
        (p.supplier, ref.valueProp) for ref in p.get_mpns()], multiple=True)
    supplier_spn_idx = supplier_parts.add_multi_index("supplier,spn", lambda p: [
        (p.supplier, ref.valueProp) for ref in p.get_spns()], multiple=True)

    suppliers: List[SupplierDescriptor] = [project.get_supplier_by_key(path.parent.name) for path in part_dbs]
    for path in part_dbs:
        for xml in load_db(path).iterparts():
            if not xml.supplierProp:
                continue
            supplier_parts.add(Part(xml))

    sch_db = load_db(schematic_path)
    bom_parts: ObjDb[BomPart] = ObjDb[BomPart]()
    bom_parts.add_multi_index("supplier,pn", lambda op: [
        (op.part.supplierProp, ref.valueProp) for ref in
        op.part.get_mpns()] if op.part.supplier else None, multiple=True)

    for sch_part in sch_db.iterparts():
        part = BomPart(sch_part)
        part.part = strategy(part.part)
        if part.part is None:
            continue

        bom_parts.add(part)

    for bom_part in bom_parts:
        sch_part_numbers = [pn.valueProp for pn in bom_part.part.get_mpns()]
        sch_supplier_part_numbers = [spn.valueProp for spn in bom_part.part.get_spns()]

        for supplier in suppliers:
            pns = supplier_pn_idx.get(supplier.uri)
            spns = supplier_spn_idx.get(supplier.uri)

            for sch_pn in sch_part_numbers:
                for supplier_part in pns.get(sch_pn, []):
                    bom_part.available_from[supplier_part.uri] = supplier_part
            for sch_spn in sch_supplier_part_numbers:
                for supplier_part in spns.get(sch_spn, []):
                    bom_part.available_from[supplier_part.uri] = supplier_part

    unresolved_parts = []
    for bom_part in bom_parts:
        af = bom_part.available_from
        if len(af) == 0:
            unresolved_parts.append(bom_part)
        elif len(af) == 1:
            bom_part.selected_part = next(iter(af.values()))
        else:
            raise EeException("unimplemented: part ({}) available from multiple suppliers: {}".
                              format(bom_part.ref, ",".join(af.keys())))

    bom_parts.add_index("uri", lambda op: op.selected_part.uri if op.selected_part else None)
    bom_parts.add_multi_index("supplier,part", lambda op: (
        op.selected_part.supplier, op.selected_part.uri) if op.selected_part else None)

    if len(unresolved_parts) and fail_on_missing_parts:
        raise EeException("The bom has parts that can't be found from any supplier")

    out_file = project.report_dir / (os.path.splitext(out_path.name)[0] + ".rst")
    make_report(out_file, unresolved_parts, bom_parts, supplier_parts)

    out_parts = PartDb()
    for bom_part in bom_parts:
        if not bom_part.selected_part:
            continue

        supplier_part = bom_part.selected_part

        part = Part(types.Part(supplier=supplier_part.supplier))
        part.add_schematic_reference(bom_part.part.get_exactly_one_schematic_reference().referenceProp)
        part.add_part_reference(supplier_part.uri)

        out_parts.add_entry(part, True)

    save_db(out_path, out_parts)