import oracledb
import csv
import io
import logging
from fastapi import HTTPException
from .. import database

logger = logging.getLogger(__name__)

def get_mappings(search: str = "", page: int = 1, per_page: int = 50,
                 sort_by: str = "sku", sort_dir: str = "asc",
                 show_deleted: bool = False, pct_filter: str = None):
    """Get paginated mappings with optional search, sorting, and pct_filter.

    pct_filter values:
      'complete'   – only SKU groups where sum(procent_pret for active rows) == 100
      'incomplete' – only SKU groups where sum < 100
      None / 'all' – no filter
    """
    if database.pool is None:
        raise HTTPException(status_code=503, detail="Oracle unavailable")

    offset = (page - 1) * per_page

    # Validate and resolve sort parameters
    allowed_sort = {
        "sku": "at.sku",
        "codmat": "at.codmat",
        "denumire": "na.denumire",
        "um": "na.um",
        "cantitate_roa": "at.cantitate_roa",
        "procent_pret": "at.procent_pret",
        "activ": "at.activ",
    }
    sort_col = allowed_sort.get(sort_by, "at.sku")
    if sort_dir.lower() not in ("asc", "desc"):
        sort_dir = "asc"
    order_clause = f"{sort_col} {sort_dir}"
    # Always add secondary sort to keep groups together
    if sort_col not in ("at.sku",):
        order_clause += ", at.sku"
    order_clause += ", at.codmat"

    with database.pool.acquire() as conn:
        with conn.cursor() as cur:
            # Build WHERE clause
            where_clauses = []
            params = {}
            if not show_deleted:
                where_clauses.append("at.sters = 0")
            if search:
                where_clauses.append("""(UPPER(at.sku) LIKE '%' || UPPER(:search) || '%'
                    OR UPPER(at.codmat) LIKE '%' || UPPER(:search) || '%'
                    OR UPPER(na.denumire) LIKE '%' || UPPER(:search) || '%')""")
                params["search"] = search
            where = "WHERE " + " AND ".join(where_clauses) if where_clauses else ""

            # Fetch ALL matching rows (no pagination yet — we need to group by SKU first)
            data_sql = f"""
                SELECT at.sku, at.codmat, na.denumire, na.um, at.cantitate_roa,
                       at.procent_pret, at.activ, at.sters,
                       TO_CHAR(at.data_creare, 'YYYY-MM-DD HH24:MI') as data_creare
                FROM ARTICOLE_TERTI at
                LEFT JOIN nom_articole na ON na.codmat = at.codmat
                {where}
                ORDER BY {order_clause}
            """
            cur.execute(data_sql, params)
            columns = [col[0].lower() for col in cur.description]
            all_rows = [dict(zip(columns, row)) for row in cur.fetchall()]

            # Group by SKU and compute pct_total for each group
            from collections import OrderedDict
            groups = OrderedDict()
            for row in all_rows:
                sku = row["sku"]
                if sku not in groups:
                    groups[sku] = []
                groups[sku].append(row)

            # Compute counts across ALL groups (before pct_filter)
            total_skus = len(groups)
            complete_skus = 0
            incomplete_skus = 0
            for sku, rows in groups.items():
                pct_total = sum(
                    (r["procent_pret"] or 0)
                    for r in rows
                    if r.get("activ") == 1
                )
                if abs(pct_total - 100) <= 0.01:
                    complete_skus += 1
                else:
                    incomplete_skus += 1

            counts = {
                "total": total_skus,
                "complete": complete_skus,
                "incomplete": incomplete_skus,
            }

            # Apply pct_filter
            if pct_filter in ("complete", "incomplete"):
                filtered_groups = {}
                for sku, rows in groups.items():
                    pct_total = sum(
                        (r["procent_pret"] or 0)
                        for r in rows
                        if r.get("activ") == 1
                    )
                    is_complete = abs(pct_total - 100) <= 0.01
                    if pct_filter == "complete" and is_complete:
                        filtered_groups[sku] = rows
                    elif pct_filter == "incomplete" and not is_complete:
                        filtered_groups[sku] = rows
                groups = filtered_groups

            # Flatten back to rows for pagination (paginate by raw row count)
            filtered_rows = [row for rows in groups.values() for row in rows]
            total = len(filtered_rows)
            page_rows = filtered_rows[offset: offset + per_page]

            # Attach pct_total and is_complete to each row for the renderer
            # Re-compute per visible group
            sku_pct = {}
            for sku, rows in groups.items():
                pct_total = sum(
                    (r["procent_pret"] or 0)
                    for r in rows
                    if r.get("activ") == 1
                )
                sku_pct[sku] = {"pct_total": pct_total, "is_complete": abs(pct_total - 100) <= 0.01}

            for row in page_rows:
                meta = sku_pct.get(row["sku"], {"pct_total": 0, "is_complete": False})
                row["pct_total"] = meta["pct_total"]
                row["is_complete"] = meta["is_complete"]

            return {
                "mappings": page_rows,
                "total": total,
                "page": page,
                "per_page": per_page,
                "pages": (total + per_page - 1) // per_page if total > 0 else 0,
                "counts": counts,
            }

def create_mapping(sku: str, codmat: str, cantitate_roa: float = 1, procent_pret: float = 100):
    """Create a new mapping. Returns dict or raises HTTPException on duplicate."""
    if not sku or not sku.strip():
        raise HTTPException(status_code=400, detail="SKU este obligatoriu")
    if not codmat or not codmat.strip():
        raise HTTPException(status_code=400, detail="CODMAT este obligatoriu")
    if database.pool is None:
        raise HTTPException(status_code=503, detail="Oracle unavailable")

    with database.pool.acquire() as conn:
        with conn.cursor() as cur:
            # Check for active duplicate
            cur.execute("""
                SELECT COUNT(*) FROM ARTICOLE_TERTI
                WHERE sku = :sku AND codmat = :codmat AND NVL(sters, 0) = 0
            """, {"sku": sku, "codmat": codmat})
            if cur.fetchone()[0] > 0:
                raise HTTPException(status_code=409, detail="Maparea SKU-CODMAT există deja")

            # Check for soft-deleted record that could be restored
            cur.execute("""
                SELECT COUNT(*) FROM ARTICOLE_TERTI
                WHERE sku = :sku AND codmat = :codmat AND sters = 1
            """, {"sku": sku, "codmat": codmat})
            if cur.fetchone()[0] > 0:
                raise HTTPException(
                    status_code=409,
                    detail="Maparea a fost ștearsă anterior",
                    headers={"X-Can-Restore": "true"}
                )

            cur.execute("""
                INSERT INTO ARTICOLE_TERTI (sku, codmat, cantitate_roa, procent_pret, activ, sters, data_creare, id_util_creare)
                VALUES (:sku, :codmat, :cantitate_roa, :procent_pret, 1, 0, SYSDATE, -3)
            """, {"sku": sku, "codmat": codmat, "cantitate_roa": cantitate_roa, "procent_pret": procent_pret})
            conn.commit()
    return {"sku": sku, "codmat": codmat}

def update_mapping(sku: str, codmat: str, cantitate_roa: float = None, procent_pret: float = None, activ: int = None):
    """Update an existing mapping."""
    if database.pool is None:
        raise HTTPException(status_code=503, detail="Oracle unavailable")

    sets = []
    params = {"sku": sku, "codmat": codmat}

    if cantitate_roa is not None:
        sets.append("cantitate_roa = :cantitate_roa")
        params["cantitate_roa"] = cantitate_roa
    if procent_pret is not None:
        sets.append("procent_pret = :procent_pret")
        params["procent_pret"] = procent_pret
    if activ is not None:
        sets.append("activ = :activ")
        params["activ"] = activ

    if not sets:
        return False

    sets.append("data_modif = SYSDATE")
    set_clause = ", ".join(sets)

    with database.pool.acquire() as conn:
        with conn.cursor() as cur:
            cur.execute(f"""
                UPDATE ARTICOLE_TERTI SET {set_clause}
                WHERE sku = :sku AND codmat = :codmat
            """, params)
            conn.commit()
            return cur.rowcount > 0

def delete_mapping(sku: str, codmat: str):
    """Soft delete (set sters=1)."""
    if database.pool is None:
        raise HTTPException(status_code=503, detail="Oracle unavailable")

    with database.pool.acquire() as conn:
        with conn.cursor() as cur:
            cur.execute("""
                UPDATE ARTICOLE_TERTI SET sters = 1, data_modif = SYSDATE
                WHERE sku = :sku AND codmat = :codmat
            """, {"sku": sku, "codmat": codmat})
            conn.commit()
            return cur.rowcount > 0

def edit_mapping(old_sku: str, old_codmat: str, new_sku: str, new_codmat: str,
                 cantitate_roa: float = 1, procent_pret: float = 100):
    """Edit a mapping. If PK changed, soft-delete old and insert new."""
    if not new_sku or not new_sku.strip():
        raise HTTPException(status_code=400, detail="SKU este obligatoriu")
    if not new_codmat or not new_codmat.strip():
        raise HTTPException(status_code=400, detail="CODMAT este obligatoriu")
    if database.pool is None:
        raise HTTPException(status_code=503, detail="Oracle unavailable")

    if old_sku == new_sku and old_codmat == new_codmat:
        # Simple update - only cantitate/procent changed
        return update_mapping(new_sku, new_codmat, cantitate_roa, procent_pret)
    else:
        # PK changed: soft-delete old, upsert new (MERGE handles existing soft-deleted target)
        with database.pool.acquire() as conn:
            with conn.cursor() as cur:
                # Mark old record as deleted
                cur.execute("""
                    UPDATE ARTICOLE_TERTI SET sters = 1, data_modif = SYSDATE
                    WHERE sku = :sku AND codmat = :codmat
                """, {"sku": old_sku, "codmat": old_codmat})
                # Upsert new record (MERGE in case target PK exists as soft-deleted)
                cur.execute("""
                    MERGE INTO ARTICOLE_TERTI t
                    USING (SELECT :sku AS sku, :codmat AS codmat FROM DUAL) s
                    ON (t.sku = s.sku AND t.codmat = s.codmat)
                    WHEN MATCHED THEN UPDATE SET
                        cantitate_roa = :cantitate_roa,
                        procent_pret = :procent_pret,
                        activ = 1, sters = 0,
                        data_modif = SYSDATE
                    WHEN NOT MATCHED THEN INSERT
                        (sku, codmat, cantitate_roa, procent_pret, activ, sters, data_creare, id_util_creare)
                        VALUES (:sku, :codmat, :cantitate_roa, :procent_pret, 1, 0, SYSDATE, -3)
                """, {"sku": new_sku, "codmat": new_codmat,
                      "cantitate_roa": cantitate_roa, "procent_pret": procent_pret})
                conn.commit()
                return True

def restore_mapping(sku: str, codmat: str):
    """Restore a soft-deleted mapping (set sters=0)."""
    if database.pool is None:
        raise HTTPException(status_code=503, detail="Oracle unavailable")

    with database.pool.acquire() as conn:
        with conn.cursor() as cur:
            cur.execute("""
                UPDATE ARTICOLE_TERTI SET sters = 0, data_modif = SYSDATE
                WHERE sku = :sku AND codmat = :codmat
            """, {"sku": sku, "codmat": codmat})
            conn.commit()
            return cur.rowcount > 0

def import_csv(file_content: str):
    """Import mappings from CSV content. Returns summary."""
    if database.pool is None:
        raise HTTPException(status_code=503, detail="Oracle unavailable")

    reader = csv.DictReader(io.StringIO(file_content))
    created = 0
    skipped_no_codmat = 0
    errors = []

    with database.pool.acquire() as conn:
        with conn.cursor() as cur:
            for i, row in enumerate(reader, 1):
                sku = row.get("sku", "").strip()
                codmat = row.get("codmat", "").strip()

                if not sku:
                    errors.append(f"Rând {i}: SKU lipsă")
                    continue

                if not codmat:
                    skipped_no_codmat += 1
                    continue

                try:
                    cantitate = float(row.get("cantitate_roa", "1") or "1")
                    procent = float(row.get("procent_pret", "100") or "100")

                    cur.execute("""
                        MERGE INTO ARTICOLE_TERTI t
                        USING (SELECT :sku AS sku, :codmat AS codmat FROM DUAL) s
                        ON (t.sku = s.sku AND t.codmat = s.codmat)
                        WHEN MATCHED THEN UPDATE SET
                            cantitate_roa = :cantitate_roa,
                            procent_pret = :procent_pret,
                            activ = 1,
                            sters = 0,
                            data_modif = SYSDATE
                        WHEN NOT MATCHED THEN INSERT
                            (sku, codmat, cantitate_roa, procent_pret, activ, sters, data_creare, id_util_creare)
                            VALUES (:sku, :codmat, :cantitate_roa, :procent_pret, 1, 0, SYSDATE, -3)
                    """, {"sku": sku, "codmat": codmat, "cantitate_roa": cantitate, "procent_pret": procent})
                    created += 1

                except Exception as e:
                    errors.append(f"Rând {i}: {str(e)}")

            conn.commit()

    return {"processed": created, "skipped_no_codmat": skipped_no_codmat, "errors": errors}

def export_csv():
    """Export all mappings as CSV string."""
    if database.pool is None:
        raise HTTPException(status_code=503, detail="Oracle unavailable")

    output = io.StringIO()
    writer = csv.writer(output)
    writer.writerow(["sku", "codmat", "cantitate_roa", "procent_pret", "activ"])

    with database.pool.acquire() as conn:
        with conn.cursor() as cur:
            cur.execute("""
                SELECT sku, codmat, cantitate_roa, procent_pret, activ
                FROM ARTICOLE_TERTI WHERE sters = 0 ORDER BY sku, codmat
            """)
            for row in cur:
                writer.writerow(row)

    return output.getvalue()

def get_csv_template():
    """Return empty CSV template."""
    output = io.StringIO()
    writer = csv.writer(output)
    writer.writerow(["sku", "codmat", "cantitate_roa", "procent_pret"])
    writer.writerow(["EXAMPLE_SKU", "EXAMPLE_CODMAT", "1", "100"])
    return output.getvalue()