# parametros.py
from fastapi import APIRouter, Request, Depends, Form, UploadFile, File
from sqlalchemy.ext.asyncio import AsyncSession
from app.database import get_session
from app.models import AliquotaUF, ParametrosFormula, SelicMensal
from typing import List
from pydantic import BaseModel
import datetime
from fastapi.templating import Jinja2Templates
from sqlalchemy.future import select
from app.database import AsyncSessionLocal
from fastapi.responses import RedirectResponse, JSONResponse
from app.models import Fatura
from fastapi import Body
from app.database import engine
import httpx
from app.models import SelicMensal
from sqlalchemy.dialects.postgresql import insert as pg_insert
import io
import csv
from fastapi.responses import StreamingResponse
import pandas as pd
from io import BytesIO
from sqlalchemy import select
from decimal import Decimal
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import text


templates = Jinja2Templates(directory="app/templates")
router = APIRouter()

# === Schemas ===
class AliquotaUFSchema(BaseModel):
    uf: str
    exercicio: int
    aliq_icms: float

    class Config:
        from_attributes = True

class ParametrosFormulaSchema(BaseModel):
    nome: str
    formula: str
    ativo: bool = True

    class Config:
        from_attributes = True


class SelicMensalSchema(BaseModel):
    mes: str  # 'YYYY-MM'
    fator: float

    class Config:
        from_attributes = True

# === Rotas ===
@router.get("/parametros")
async def parametros_page(
    request: Request,
    session: AsyncSession = Depends(get_session),
):
    # Fórmulas
    result_formula = await session.execute(
        text("SELECT id, nome, formula, ativo FROM faturas.parametros_formula ORDER BY id DESC")
    )
    formulas = [dict(row) for row in result_formula.mappings()]

    # SELIC (dados + última competência)
    result_selic = await session.execute(
        text("SELECT ano, mes, percentual FROM faturas.selic_mensal ORDER BY ano DESC, mes DESC")
    )
    selic_dados = [dict(row) for row in result_selic.mappings()]
    ultima_data_selic = (
        f"{selic_dados[0]['mes']:02d}/{selic_dados[0]['ano']}" if selic_dados else None
    )

    # Alíquotas por UF
    result_aliquotas = await session.execute(
        text("""
            SELECT uf,
                exercicio,
                aliq_icms AS aliquota
            FROM faturas.aliquotas_uf
            ORDER BY uf ASC, exercicio DESC
        """)
    )
    aliquotas_uf = [dict(row) for row in result_aliquotas.mappings()]


    # Campos disponíveis da tabela Fatura para o editor
    campos_fatura = [c.name for c in Fatura.__table__.columns]

    return templates.TemplateResponse(
        "parametros.html",
        {
            "request": request,
            "parametros": None,            # evita erro no Jinja
            "formulas": formulas,          # <-- usado no template
            "selic_dados": selic_dados,    # <-- usado no template
            "aliquotas_uf": aliquotas_uf,  # se precisar em JS
            "ultima_data_selic": ultima_data_selic,
            "data_maxima": None,
            "campos_fatura": campos_fatura,
        },
    )



@router.post("/parametros/editar/{param_id}")
async def editar_parametro(param_id: int, request: Request):
    data = await request.json()
    async with AsyncSessionLocal() as session:
        param = await session.get(ParametrosFormula, param_id)
        if param:
            param.nome = data.get("nome", param.nome)
            param.formula = data.get("formula", param.formula)
            param.ativo = data.get("ativo", param.ativo)
            await session.commit()
            return {"success": True}
        return {"success": False, "error": "Não encontrado"}

@router.post("/parametros/ativar/{param_id}")
async def ativar_parametro(param_id: int, request: Request):
    data = await request.json()
    ativo = bool(data.get("ativo", True))
    async with AsyncSessionLocal() as session:
        param = await session.get(ParametrosFormula, param_id)
        if not param:
            return JSONResponse(status_code=404, content={"error": "Parâmetro não encontrado"})
        param.ativo = ativo
        await session.commit()
        return {"success": True}

@router.get("/parametros/delete/{param_id}")
async def deletar_parametro(param_id: int):
    async with AsyncSessionLocal() as session:
        param = await session.get(ParametrosFormula, param_id)
        if not param:
            return RedirectResponse("/parametros?erro=1&msg=Parâmetro não encontrado", status_code=303)
        await session.delete(param)
        await session.commit()
        return RedirectResponse("/parametros?ok=1&msg=Parâmetro removido", status_code=303)

@router.post("/parametros/testar")
async def testar_formula(db: AsyncSession = Depends(get_session), data: dict = Body(...)):
    formula = data.get("formula")

    exemplo = await db.execute(select(Fatura).limit(1))
    fatura = exemplo.scalar_one_or_none()
    if not fatura:
        return {"success": False, "error": "Sem dados para teste."}

    try:
        contexto = {col.name: getattr(fatura, col.name) for col in Fatura.__table__.columns}
        resultado = eval(formula, {}, contexto)
        return {"success": True, "resultado": resultado}
    except Exception as e:
        return {"success": False, "error": str(e)}


@router.get("/parametros/aliquotas")
async def listar_aliquotas(uf: str | None = None, db: AsyncSession = Depends(get_session)):
    stmt = select(AliquotaUF).order_by(AliquotaUF.uf, AliquotaUF.exercicio.desc())
    if uf:
        stmt = stmt.where(AliquotaUF.uf == uf)

    rows = (await db.execute(stmt)).scalars().all()
    return [
        {"uf": r.uf, "exercicio": int(r.exercicio), "aliquota": float(r.aliq_icms)}
        for r in rows
    ]


@router.post("/parametros/aliquotas")
async def adicionar_aliquota(aliq: AliquotaUFSchema, db: AsyncSession = Depends(get_session)):
    result = await db.execute(
        select(AliquotaUF).filter_by(uf=aliq.uf, exercicio=aliq.exercicio)
    )
    existente = result.scalar_one_or_none()

    if existente:
        existente.aliq_icms = aliq.aliq_icms  # atualizado
    else:
        novo = AliquotaUF(**aliq.dict())
        db.add(novo)

    await db.commit()
    return RedirectResponse(url="/parametros?ok=true&msg=Alíquota salva com sucesso", status_code=303)
    

@router.get("/parametros/formulas", response_model=List[ParametrosFormulaSchema])
async def listar_formulas(db: AsyncSession = Depends(get_session)):
    result = await db.execute(select(ParametrosFormula).order_by(ParametrosFormula.nome))
    return result.scalars().all()

@router.post("/parametros/formulas")
async def salvar_formula(form: ParametrosFormulaSchema, db: AsyncSession = Depends(get_session)):
    result = await db.execute(
        select(ParametrosFormula).filter_by(nome=form.nome)
    )
    existente = result.scalar_one_or_none()

    if existente:
        existente.formula = form.formula
        existente.ativo = form.ativo
    else:
        novo = ParametrosFormula(nome=form.nome, formula=form.formula, ativo=form.ativo)
        db.add(novo)

    await db.commit()
    return RedirectResponse(url="/parametros?ok=true&msg=Parâmetro salvo com sucesso", status_code=303)

@router.get("/parametros/selic", response_model=List[SelicMensalSchema])
async def listar_selic(db: AsyncSession = Depends(get_session)):
    result = await db.execute(select(SelicMensal).order_by(SelicMensal.mes.desc()))
    return result.scalars().all()


@router.post("/parametros/selic/importar")
async def importar_selic(request: Request, data_maxima: str = Form(None)):
    try:
        hoje = datetime.date.today()
        inicio = datetime.date(hoje.year - 5, 1, 1)
        fim = datetime.datetime.strptime(data_maxima, "%Y-%m-%d").date() if data_maxima else hoje

        url = (
            f"https://api.bcb.gov.br/dados/serie/bcdata.sgs.4390/dados?"
            f"formato=json&dataInicial={inicio.strftime('%d/%m/%Y')}&dataFinal={fim.strftime('%d/%m/%Y')}"
        )

        async with httpx.AsyncClient() as client:
            response = await client.get(url)
            response.raise_for_status()
            dados = response.json()

        registros = []
        for item in dados:
            data = datetime.datetime.strptime(item['data'], "%d/%m/%Y")
            ano, mes = data.year, data.month
            percentual = float(item['valor'].replace(',', '.'))
            registros.append({"ano": ano, "mes": mes, "percentual": percentual})

        async with engine.begin() as conn:
            stmt = pg_insert(SelicMensal.__table__).values(registros)
            upsert_stmt = stmt.on_conflict_do_update(
                index_elements=['ano', 'mes'],
                set_={'percentual': stmt.excluded.percentual}
            )
            await conn.execute(upsert_stmt)

        return RedirectResponse("/parametros?aba=selic", status_code=303)

    except Exception as e:
        return RedirectResponse(f"/parametros?erro=1&msg={str(e)}", status_code=303)

@router.get("/parametros/aliquotas/template")
def baixar_template_excel():
    df = pd.DataFrame(columns=["UF", "Exercício", "Alíquota"])
    df.loc[0] = ["SP", "2025", "18"]  # exemplo opcional
    df.loc[1] = ["MG", "2025", "12"]  # exemplo opcional

    output = BytesIO()
    with pd.ExcelWriter(output, engine='openpyxl') as writer:
        df.to_excel(writer, sheet_name='Template', index=False)

        # Adiciona instrução como observação na célula A5 (linha 5)
        sheet = writer.sheets['Template']
        sheet.cell(row=5, column=1).value = (
            "⚠️ Após preencher, salve como CSV (.csv separado por vírgulas) para importar no sistema."
        )

    output.seek(0)
    return StreamingResponse(
        output,
        media_type='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
        headers={"Content-Disposition": "attachment; filename=template_aliquotas.xlsx"}
    )

@router.post("/parametros/aliquotas/salvar")
async def salvar_aliquota(payload: dict, db: AsyncSession = Depends(get_session)):
    uf = (payload.get("uf") or "").strip().upper()
    exercicio = int(payload.get("exercicio") or 0)
    aliquota = Decimal(str(payload.get("aliquota") or "0"))

    orig_uf = (payload.get("original_uf") or "").strip().upper() or uf
    orig_ex = int(payload.get("original_exercicio") or 0) or exercicio

    if not uf or not exercicio or aliquota <= 0:
        return JSONResponse(status_code=400, content={"error": "UF, exercício e alíquota são obrigatórios."})

    # busca pelo registro original (antes da edição)
    stmt = select(AliquotaUF).where(
        AliquotaUF.uf == orig_uf,
        AliquotaUF.exercicio == orig_ex
    )
    existente = (await db.execute(stmt)).scalar_one_or_none()

    if existente:
        # atualiza (inclusive a chave, se mudou)
        existente.uf = uf
        existente.exercicio = exercicio
        existente.aliq_icms = aliquota
    else:
        # não existia o original -> upsert padrão
        db.add(AliquotaUF(uf=uf, exercicio=exercicio, aliq_icms=aliquota))

    await db.commit()
    return {"success": True}

@router.post("/parametros/aliquotas/importar")
async def importar_aliquotas_csv(arquivo: UploadFile = File(...), db: AsyncSession = Depends(get_session)):
    content = await arquivo.read()
    text = content.decode("utf-8", errors="ignore")

    # tenta ; depois ,
    sniffer = csv.Sniffer()
    dialect = sniffer.sniff(text.splitlines()[0] if text else "uf;exercicio;aliquota")
    reader = csv.DictReader(io.StringIO(text), dialect=dialect)

    count = 0
    for row in reader:
        uf = (row.get("uf") or row.get("UF") or "").strip().upper()
        exercicio_str = (row.get("exercicio") or row.get("ano") or "").strip()
        try:
            exercicio = int(exercicio_str)
        except Exception:
            continue
        aliquota_str = (row.get("aliquota") or row.get("aliq_icms") or "").replace(",", ".").strip()

        if not uf or not exercicio or not aliquota_str:
            continue

        try:
            aliquota = Decimal(aliquota_str)
        except Exception:
            continue

        stmt = select(AliquotaUF).where(AliquotaUF.uf == uf, AliquotaUF.exercicio == exercicio)
        existente = (await db.execute(stmt)).scalar_one_or_none()

        if existente:
            existente.aliq_icms = aliquota
        else:
            db.add(AliquotaUF(uf=uf, exercicio=exercicio, aliq_icms=aliquota))

        count += 1

    await db.commit()
    return {"success": True, "qtd": count}

@router.delete("/parametros/aliquotas/{uf}/{exercicio}")
async def excluir_aliquota(uf: str, exercicio: int, db: AsyncSession = Depends(get_session)):
    stmt = select(AliquotaUF).where(
        AliquotaUF.uf == uf.upper(),
        AliquotaUF.exercicio == exercicio
    )
    row = (await db.execute(stmt)).scalar_one_or_none()
    if not row:
        return JSONResponse(status_code=404, content={"error": "Registro não encontrado."})

    await db.delete(row)
    await db.commit()
    return {"success": True}