"""AI-generated form field definitions per commodity — cached in SQLite for consistency."""

from __future__ import annotations

import json
import os
import sqlite3
from typing import Any

from openai import OpenAI

from server.catalog import get_commodity, summarize_row
from server.pr_lines import INTERVAL_ORDER

# Used when the model (or legacy cache) emits text fields or too few options.
GENERIC_SELECT_FALLBACK = (
    "Standard / typical requirement",
    "Enhanced vs baseline",
    "Economy / essential only",
    "Pilot or limited scope",
    "Strategic priority program",
    "Other — use specification notes below",
)

SCHEMA_GEN_SYSTEM = """You design procurement intake forms for a single catalogue commodity (segment → family → class → commodity).

Return ONE JSON object only (no markdown). Shape:
{
  "fields": [
    {
      "id": "stable_snake_case_id",
      "label": "Full question text shown to the user (no Q1/Q2 prefixes)",
      "type": "select" | "chips" | "number",
      "options": ["required for select and chips: 3–12 distinct, short option strings"],
      "unit": "ONLY for type number: short suffix shown next to the input (e.g. kg, lb, mm, in, %)"
    }
  ]
}

Rules:
- 3 to 7 fields. Labels must be clear procurement questions for THIS commodity type.
- Do NOT include: number of deliveries, delivery interval/frequency, year for scheduling, or a generic "other / free text specifications" field — the application collects those separately.
- **No open-ended typing:** NEVER use type "text" or "textarea". Users must tap choices only.
- Prefer **select** with 5–12 concise options for objectives, scope, methodology, audience, timing, risk, quality level, etc.
- Use **chips** for 3–8 mutually exclusive options when labels are short (single choice — same as select, shown as buttons).
- Use **number** only for true numeric values (counts, currency amounts, percentages, sizes, weights, dimensions).
- For **every number field**, set **"unit"** to the metric users should enter (e.g. `"kg"` for weight capacity, `"mm"` for seat depth, `"lb"` only if Imperial is explicit). Never leave unit ambiguous when the question is a measurement.
- Every option string must be self-contained (no reliance on free-form explanations). If a case might need nuance, add an option such as "Other — see specification notes below".
- Use stable `id` values (snake_case) — they are keys in saved data.
- Same commodity must always get the same structure when regenerated; the app caches by commodity code, but ids and intent must stay consistent if you see similar commodities.
"""


def ensure_form_schema_table(conn: sqlite3.Connection) -> None:
    conn.execute(
        """
        CREATE TABLE IF NOT EXISTS commodity_form_schemas (
            commodity_code INTEGER PRIMARY KEY,
            schema_json TEXT NOT NULL,
            updated_at TEXT DEFAULT CURRENT_TIMESTAMP
        )
        """
    )
    conn.commit()


def _load_cached(conn: sqlite3.Connection, commodity_code: int) -> dict[str, Any] | None:
    cur = conn.cursor()
    cur.execute(
        "SELECT schema_json FROM commodity_form_schemas WHERE commodity_code = ?",
        (commodity_code,),
    )
    row = cur.fetchone()
    if not row:
        return None
    try:
        return json.loads(row[0])
    except json.JSONDecodeError:
        return None


def _save_cache(conn: sqlite3.Connection, commodity_code: int, schema: dict[str, Any]) -> None:
    conn.execute(
        """
        INSERT INTO commodity_form_schemas (commodity_code, schema_json, updated_at)
        VALUES (?, ?, datetime('now'))
        ON CONFLICT(commodity_code) DO UPDATE SET
          schema_json = excluded.schema_json,
          updated_at = datetime('now')
        """,
        (commodity_code, json.dumps(schema, ensure_ascii=False)),
    )
    conn.commit()


_FALLBACK_FIELDS_RAW: list[dict[str, Any]] = [
    {
        "id": "primary_scope",
        "label": "What is the primary scope or geography for this requirement?",
        "type": "select",
        "options": [
            "Local / single site",
            "Regional",
            "National",
            "International",
            "Multi-region program",
            "To be determined",
        ],
    },
    {
        "id": "scale_band",
        "label": "What scale band best matches expected volume or spend?",
        "type": "chips",
        "options": [
            "Pilot / small",
            "Medium",
            "Large",
            "Enterprise-wide",
            "Not yet estimated",
        ],
    },
    {
        "id": "compliance_focus",
        "label": "Which compliance themes apply (if any)?",
        "type": "select",
        "options": [
            "None identified yet",
            "Data privacy / residency",
            "Safety / quality standards",
            "Financial / audit controls",
            "Industry-specific regulations",
            "Mixed — see specification notes",
        ],
    },
]


def _fallback_schema() -> dict[str, Any]:
    return {
        "fields": [_coerce_field_selectable(dict(f)) for f in _FALLBACK_FIELDS_RAW],
        "source": "fallback",
    }


def _coerce_field_selectable(entry: dict[str, Any]) -> dict[str, Any]:
    """Ensure fields are selectable (select/chips) or number — never free-text."""
    typ = str(entry.get("type") or "select").lower()
    if typ in ("text", "textarea"):
        typ = "select"
    elif typ == "number":
        out = {**entry, "type": "number"}
        out.pop("options", None)
        unit = str(out.get("unit") or "").strip()
        if unit:
            out["unit"] = unit[:24]
        else:
            out.pop("unit", None)
        return out
    elif typ not in ("select", "chips"):
        typ = "select"

    opts_raw = entry.get("options")
    clean: list[str] = []
    if isinstance(opts_raw, list):
        clean = [str(o).strip() for o in opts_raw if str(o).strip()]
    if len(clean) < 2:
        clean = list(GENERIC_SELECT_FALLBACK)
    return {**entry, "type": typ, "options": clean}


def _validate_and_normalize(raw: dict[str, Any]) -> dict[str, Any]:
    fields_out: list[dict[str, Any]] = []
    seen_ids: set[str] = set()
    for f in raw.get("fields") or []:
        if not isinstance(f, dict):
            continue
        fid = str(f.get("id") or "").strip()
        label = str(f.get("label") or "").strip()
        typ = str(f.get("type") or "select").lower()
        if not fid or not label:
            continue
        if fid in seen_ids:
            continue
        seen_ids.add(fid)
        if typ not in ("select", "number", "text", "chips", "textarea"):
            typ = "select"
        opts = f.get("options")
        entry: dict[str, Any] = {"id": fid, "label": label, "type": typ}
        if typ in ("select", "chips") and isinstance(opts, list) and opts:
            entry["options"] = [str(o) for o in opts if str(o).strip()]
        if typ == "number":
            u = str(f.get("unit") or "").strip()
            if u:
                entry["unit"] = u[:24]
        fields_out.append(_coerce_field_selectable(entry))
    if len(fields_out) < 1:
        return _fallback_schema()
    return {"fields": fields_out, "source": "openai"}


def _coerce_cached_schema(cached: dict[str, Any]) -> dict[str, Any]:
    """Upgrade legacy cached schemas (text/textarea) to selectable controls."""
    fields_in = cached.get("fields") or []
    fields_out: list[dict[str, Any]] = []
    seen_ids: set[str] = set()
    for f in fields_in:
        if not isinstance(f, dict):
            continue
        fid = str(f.get("id") or "").strip()
        label = str(f.get("label") or "").strip()
        if not fid or not label or fid in seen_ids:
            continue
        seen_ids.add(fid)
        typ = str(f.get("type") or "select").lower()
        entry: dict[str, Any] = {"id": fid, "label": label, "type": typ}
        opts = f.get("options")
        if typ in ("select", "chips") and isinstance(opts, list) and opts:
            entry["options"] = [str(o) for o in opts if str(o).strip()]
        if typ == "number":
            u = str(f.get("unit") or "").strip()
            if u:
                entry["unit"] = u[:24]
        fields_out.append(_coerce_field_selectable(entry))
    if len(fields_out) < 1:
        return _fallback_schema()
    out = {**cached, "fields": fields_out, "source": cached.get("source", "cache")}
    out["interval_options"] = INTERVAL_ORDER
    return out


def generate_schema_with_llm(row: dict[str, Any]) -> dict[str, Any]:
    api_key = os.environ.get("OPENAI_API_KEY")
    if not api_key:
        return _fallback_schema()

    s = summarize_row(row)
    user_block = json.dumps(
        {
            "segment_code": s.get("segment_code"),
            "family_code": s.get("family_code"),
            "class_code": s.get("class_code"),
            "commodity_code": s.get("commodity_code"),
            "path": s.get("path"),
            "commodity_title": s.get("commodity_title"),
            "commodity_definition": s.get("commodity_definition"),
        },
        ensure_ascii=False,
    )

    client = OpenAI(api_key=api_key)
    resp = client.chat.completions.create(
        model=os.environ.get("OPENAI_MODEL", "gpt-4o-mini"),
        messages=[
            {"role": "system", "content": SCHEMA_GEN_SYSTEM},
            {"role": "user", "content": user_block},
        ],
        temperature=0.2,
        response_format={"type": "json_object"},
    )
    text = (resp.choices[0].message.content or "").strip()
    try:
        parsed = json.loads(text)
    except json.JSONDecodeError:
        return _fallback_schema()
    return _validate_and_normalize(parsed)


def get_or_create_schema(conn: sqlite3.Connection, commodity_code: int) -> dict[str, Any]:
    ensure_form_schema_table(conn)
    cached = _load_cached(conn, commodity_code)
    if cached and cached.get("fields"):
        return _coerce_cached_schema(cached)

    row = get_commodity(conn, commodity_code)
    if not row:
        return {"fields": [], "error": "commodity_not_found", "interval_options": INTERVAL_ORDER}

    schema = generate_schema_with_llm(row)
    if schema.get("fields"):
        _save_cache(conn, commodity_code, schema)
    schema["interval_options"] = INTERVAL_ORDER
    return schema