"""
Phase 2 — Step 2.4: crm_customers  (Firestore → Postgres)

Reads the 'crm_customers' Firestore collection.
- Strips legacy fields: 'negotiating', 'has_problem'
- Converts Firestore DatetimeWithNanoseconds → UTC datetime
- Converts nested dicts/lists → JSONB-ready Python objects

After this runs, the FK constraints on crm_quotations, crm_comms_log,
crm_media, and crm_orders (all inserted in Phase 1 with FK enforcement
suppressed) become valid.

Run on VPS:
    docker compose exec backend python -m migration.migrate_crm_customers
"""

import asyncio
import sys
from datetime import datetime, timezone

from sqlalchemy.dialects.postgresql import insert as pg_insert

from crm.orm import CrmCustomer
from shared.firebase import init_firebase, get_db as get_firestore
from migration.utils import AsyncPgSession, parse_dt, log_run, pg_count

SCRIPT = "migrate_crm_customers"
COLLECTION = "crm_customers"

_LEGACY_FIELDS = {"negotiating", "has_problem"}

_VALID_STATUSES = {
    "lead", "active", "inactive", "archived",
    "prospect", "churned", "vip",
}


def _now_utc() -> datetime:
    return datetime.now(timezone.utc)


def _coerce_dt(val) -> datetime | None:
    """Handle both Firestore DatetimeWithNanoseconds and ISO strings."""
    if val is None:
        return None
    if isinstance(val, datetime):
        return val.replace(tzinfo=timezone.utc) if val.tzinfo is None else val
    return parse_dt(str(val))


def _coerce_list(val, default=None) -> list:
    if isinstance(val, list):
        return val
    return default if default is not None else []


async def run() -> None:
    init_firebase()
    fs = get_firestore()
    if fs is None:
        print("ERROR: Firebase not initialised.", file=sys.stderr)
        sys.exit(1)

    docs = list(fs.collection(COLLECTION).stream())
    source_count = len(docs)
    print(f"Source (Firestore): {source_count} crm_customers documents")

    if source_count == 0:
        print("Nothing to migrate.")
        await log_run(SCRIPT, 0, 0, notes="source empty")
        return

    records = []
    skipped = 0
    for doc in docs:
        d = doc.to_dict()

        # Strip legacy fields
        for f in _LEGACY_FIELDS:
            d.pop(f, None)

        # folder_id is NOT NULL UNIQUE — skip docs missing it
        folder_id = d.get("folder_id") or ""
        if not folder_id:
            print(f"  WARNING: customer {doc.id} has no folder_id — skipping", file=sys.stderr)
            skipped += 1
            continue

        # relationship_status — normalise unknown values to 'lead'
        rel_status = d.get("relationship_status") or "lead"
        if rel_status not in _VALID_STATUSES:
            rel_status = "lead"

        # contacts / notes — Firestore stores as list of maps
        contacts = _coerce_list(d.get("contacts"))
        # Serialise nested Pydantic-style objects to plain dicts
        contacts = [c if isinstance(c, dict) else vars(c) for c in contacts]

        notes = _coerce_list(d.get("notes"))
        notes = [n if isinstance(n, dict) else vars(n) for n in notes]

        # location — may be a map or None
        location = d.get("location")
        if location and not isinstance(location, dict):
            location = vars(location)

        tags = _coerce_list(d.get("tags"))
        owned_items = _coerce_list(d.get("owned_items"))
        owned_items = [o if isinstance(o, dict) else vars(o) for o in owned_items]

        linked_user_ids = _coerce_list(d.get("linked_user_ids"))

        technical_issues    = _coerce_list(d.get("technical_issues"))
        install_support     = _coerce_list(d.get("install_support"))
        transaction_history = _coerce_list(d.get("transaction_history"))

        crm_summary = d.get("crm_summary")
        if crm_summary and not isinstance(crm_summary, dict):
            crm_summary = vars(crm_summary)

        created_at = _coerce_dt(d.get("created_at")) or _now_utc()
        updated_at = _coerce_dt(d.get("updated_at")) or _now_utc()

        records.append({
            "id":                  doc.id,
            "firestore_id":        doc.id,
            "title":               d.get("title"),
            "name":                d.get("name") or "",
            "surname":             d.get("surname"),
            "organization":        d.get("organization"),
            "religion":            d.get("religion"),
            "language":            d.get("language") or "el",
            "folder_id":           folder_id,
            "relationship_status": rel_status,
            "nextcloud_folder":    d.get("nextcloud_folder"),
            "contacts":            contacts,
            "notes":               notes,
            "location":            location,
            "tags":                tags,
            "owned_items":         owned_items,
            "linked_user_ids":     linked_user_ids,
            "technical_issues":    technical_issues,
            "install_support":     install_support,
            "transaction_history": transaction_history,
            "crm_summary":         crm_summary,
            "created_at":          created_at,
            "updated_at":          updated_at,
        })

    actual_source = source_count - skipped
    print(f"  {skipped} skipped (missing folder_id), {actual_source} to insert")

    async with AsyncPgSession() as session:
        async with session.begin():
            stmt = pg_insert(CrmCustomer).values(records)
            stmt = stmt.on_conflict_do_nothing(index_elements=["id"])
            await session.execute(stmt)
            dest_count = await pg_count(session, "crm_customers")

    if dest_count < actual_source:
        msg = f"Count mismatch: expected>={actual_source}  postgres={dest_count}"
        print(f"ERROR: {msg}", file=sys.stderr)
        await log_run(SCRIPT, source_count, dest_count, success=False, notes=msg)
        sys.exit(1)

    print(f"Postgres: {dest_count} rows ✓")
    await log_run(SCRIPT, source_count, dest_count,
                  notes=f"{skipped} skipped (no folder_id)" if skipped else None)


if __name__ == "__main__":
    asyncio.run(run())