#!/usr/bin/env python3

import json
from pathlib import Path
from collections import OrderedDict


DATA = Path("data")
REPORTS = Path("reports/updateChanges")

VERSION_DIRS = sorted(
                [d for d in DATA.iterdir() if d.is_dir()],
                key=lambda p: [int(x) for x in p.name.split(".")]
                )
VERSIONS = [v.name for v in VERSION_DIRS]

def modules():
    first = VERSION_DIRS[0]
    return sorted(f.stem for f in first.glob("*.json"))


class Operation(object):
    def __init__(self, data, source):
        self.condition = None
        self.via = None
        self.unresolved = False
        self.__dict__.update(data)
        self.sources = [source,]
        self.tables_unknown = not self.tables
        if not self.tables:
            self.tables = ('unknown',)

    def toText(self):
        marker = "unresolved " if self.unresolved else ""
        text = [f"- **{self.phase}** {marker}`{self.operation}`"]
        if self.condition:
            text.append( f"  - condition: `{self.condition}`")
        if self.object:
            text.append( f"  - object: `{self.object}`" )
        if self.via:
            chain = " -> ".join(f"{v['method']} (Zeile {v['line']})" for v in self.via)
            text.append( f"  - via: {chain}" )
        if self.tables_unknown:
            text.append("  - Tabelle nicht erkannt!")
        text.append( "  - files:" )
        for s in self.sources:
            text.append( f"    - `{s['file']}`"  )
        if self.args:
            text.append( f"  - args: `{', '.join(self.args)}`"  )
        if self.kwargs:
            text.append("  - kwargs:")
            for k, v in self.kwargs.items():
                text.append( f"    - {k}: `{v}`" )
        if self.code:
            text.append("  - code:")
            text.append(f"    '{self.code}'")
        text.append('')
        return '\n'.join(text)
    
    @property
    def key(self):
        # kwargs are intentionally ignored for now.
        # The key is only used to collapse repeated migration blocks;
        # it is not intended to establish semantic equality.
        return ( self.phase, self.operation, self.object,
                tuple(self.tables), tuple(self.args), self.code,  )

class Table:

    _allTables = {}

    @classmethod
    def get(cls, name):
        if name not in cls._allTables:
            cls._allTables[name] = cls(name)
        return cls._allTables[name]

    @classmethod
    def addObject(cls, obj):
        new = False
        for t in obj.tables:
            if cls.get(t).add(obj):
                new = True
        return new

    def __init__(self, name):
        self.versions = {key: {} for key in VERSIONS}  # was angezeigt wird

        # _current_presence: der TATSÄCHLICHE, vollständige Operationsbestand
        # der Version, die wir gerade verarbeiten (unabhängig davon, ob wir
        # sie anzeigen). _prev_presence: derselbe vollständige Bestand der
        # UNMITTELBAR VORHERIGEN Version. Nur dieser Vergleich (nicht ein
        # kumulatives "jemals gesehen") ist korrekt: taucht ein Block in
        # einer Zwischenversion NICHT auf (weil er dort entfernt/ersetzt
        # wurde) und kommt später identisch zurück, muss er wieder als neu
        # gelten - auch wenn exakt derselbe Code schon vor langer Zeit
        # existierte.
        self._current_version = None
        self._current_presence = {}
        self._prev_presence = {}

    def _advance_to(self, version):
        if version == self._current_version:
            return
        if self._current_version is not None:
            self._prev_presence = self._current_presence
        self._current_version = version
        self._current_presence = {}

    def add(self, obj):
        self._advance_to(obj.version)
        key = obj.key

        already_in_this_version = key in self._current_presence
        self._current_presence[key] = obj  # immer im tatsächlichen Bestand vermerken

        if already_in_this_version:
            return None  # exakt dieselbe Operation kam mehrfach in DIESER Version vor

        if key in self._prev_presence:
            return None  # unverändert gegenüber der unmittelbar vorherigen Version

        self.versions[obj.version][key] = obj
        return obj

class Module(object):
    def __init__(self, module):
        self.name = module
        self.tables = {}
        self.operations = []
        
    def read_data(self):
        for version in VERSION_DIRS:
            
            vers = version.name

            infile = version / f"{self.name}.json"
            if not infile.exists():
                continue

            data = json.loads(infile.read_text())
            
            for f in data["files"]:
                f['version'] = vers
                
                for o in f['operations']:
                    source = {'module': f['module'],
                              'file': f['file'],
                              'class': f['class'],
                              'method': f['method'],
                              'line': f['line']}
                    op = Operation(o, source)
                    op.version = vers
                    if Table.addObject(op):
                        for t in op.tables:
                            if t not in self.tables:
                                self.tables[t] = Table.get(t)

    def write_data(self):
    
        outfile = REPORTS / f"{self.name}.md"
    
        with outfile.open("w", encoding="utf8") as out:
    
            out.write(f"# modul {self.name}\n\n")
            
            # iterate all tables
            for t in sorted(self.tables):
                table = self.tables[t]
                
                out.write(f"\n## Tabelle {t}\n")

                # iterate all Versions
                for tName, ops in sorted(table.versions.items()):
                    if not ops:
                        continue
                    
                    new_version = tName

                    # iterate all files / occureces
                    for op in ops.values():
                        
                        if new_version:
                            out.write("\n")
                            out.write(f"### {new_version}\n\n")
                            new_version = None
                        out.write(op.toText())
                    out.write("\n")
        


def main():

    REPORTS.mkdir(exist_ok=True)

    for module in modules():

        print(module)
        
        mod = Module(module)
        
        mod.read_data()
        mod.write_data()


if __name__ == "__main__":
    main()