import { useState, useEffect, useMemo, useCallback } from "react";
import {
  TextField,
  Dialog,
  DialogTitle,
  DialogContent,
  DialogActions,
  Button,
  List,
  ListItemButton,
  ListItemIcon,
  ListItemText,
  Typography,
  InputAdornment,
  IconButton,
  Checkbox,
  CircularProgress,
} from "@mui/material";
import ClearIcon from "@mui/icons-material/Clear";
import FilterTableBuilder from "../utils/filterTableBuilder";
import { apiRequest } from "../api/request";
import { useApiHeaders } from "./ApiContext";

export default function ListVirtual({
  id,
  label,
  name,
  url,
  lengthData = 100,
  getData,
  defaultValue,
  value,
  required,
  disabled,
  error = false,
  size = 'medium',
  helperText,
  filter,
	isApiGo = false,
  multiple,
  customSxTextField = {},
  joins = [],
  warningCheck,
}) {
  const headersRequest = useApiHeaders();
  const [open, setOpen] = useState(false);
  const [search, setSearch] = useState("");
  const [rows, setRows] = useState([]);
  const [selected, setSelected] = useState(null);
  const [loading, setLoading] = useState(false);
  const [selectAllLoading, setSelectAllLoading] = useState(false);
  const [offset, setOffset] = useState(0);
  const [totalRecord, setTotalRecord] = useState(0);

    const debounce = (fn, delay = 400) => {
			let timeout;

			return (...args) => {
				clearTimeout(timeout);

				timeout = setTimeout(() => {
					fn(...args);
				}, delay);
			};
    };

  const fetchData = useCallback(async (keyword = "", currentOffset = 0, isAppend = false) => {
    setLoading(true);

    const payload = new FilterTableBuilder()
      .setPaging(currentOffset, lengthData)
      .setOrder([name], true);

    if (keyword) payload.like(name, keyword);
    
    if (filter && filter.length > 0) {
      filter.forEach(f => payload.where(f.logic_operator || "=", f.name, f.value, f.operator || "AND", f.value1 || null, f.table_name || null));
    }

    if (Array.isArray(filter) && filter.some(f => f.name === "company_id")) {
      payload.addJoin("company", ["name"]);
    }

    joins.forEach(join => {
      payload.addJoin(join.table, join.columns);
    });

    try {
      const res = await apiRequest.search(
				url, 
				payload.build(),
        {
          headers: headersRequest
        },
        isApiGo,
			);
      const incomingData = res.data || [];
      
      setRows(prev => isAppend ? [...prev, ...incomingData] : incomingData);
      setTotalRecord(res.totalRecord || 0);
      setOffset(currentOffset);
    } catch (err) {
      console.error("Fetch Error:", err);
    } finally {
      setLoading(false);
    }
  }, [url, name, lengthData, filter]);

  const handleScroll = (e) => {
    const { scrollTop, scrollHeight, clientHeight } = e.currentTarget;

    const isAtBottom = scrollHeight - scrollTop <= clientHeight + 20;

    if (isAtBottom && !loading && rows.length < totalRecord) {
      const nextOffset = offset + lengthData;

      fetchData(search, nextOffset, true);
    }
  };

  const debouncedFetch = useMemo(
    () =>
      debounce((keyword) => {
        setOffset(0); 
        fetchData(keyword, 0, false);
      }, 400),
    [fetchData]
  );

  useEffect(() => {
    if (open) {
        setOffset(0);
        fetchData(search, 0, false);
    }
  }, [open]);

  const fetchDefaultValue = async (value) => {
    setLoading(true);

    const payload = new FilterTableBuilder().setPaging(0, lengthData);

    if (multiple) {
      payload.in("id", value);        // value = [1,2,3]
    } else {
      payload.equal("id", value);     // value = 1
    }

    try {
      const res = await apiRequest.search(
        url,
        payload.build(),
        {
          headers: headersRequest,
        },
        isApiGo,
      );

      const data = res.data || [];

      setSelected(multiple ? data : data[0] || null);
    } catch (err) {
      console.error(err);
    } finally {
      setLoading(false);
    }
  };

  useEffect(() => {
    if (defaultValue == null) return;

    if (multiple) {
      // kosong, jangan request
      if (Array.isArray(defaultValue) && defaultValue.length === 0) {
        setSelected([]);
        return;
      }

      // object
      if (
        Array.isArray(defaultValue) &&
        typeof defaultValue[0] === "object"
      ) {
        setSelected(defaultValue);
        return;
      }
    } else {
      if (typeof defaultValue === "object" && !Array.isArray(defaultValue)) {
        setSelected(defaultValue);
        return;
      }
    }

    fetchDefaultValue(defaultValue);
  }, [defaultValue, multiple]);

  const handleSelect = (row) => {
    if (!multiple) {
      setSelected(row);
      setOpen(false);
      setSearch("");
      getData?.(row);
      return;
    }

    setSelected((prev) => {
      const current = Array.isArray(prev) ? prev : [];

      const exists = current.some((x) => x.id === row.id);

      const result = exists
        ? current.filter((x) => x.id !== row.id)
        : [...current, row];

      getData?.(result);

      return result;
    });
  };

  const handleClear = () => {
    setSelected(multiple ? [] : null);
    setSearch("");
    setRows([]);

    getData?.(multiple ? [] : null);
  };

  // NEW: helper untuk memanggil warningCheck dengan aman
  const getRowWarning = useCallback(
    (row) => {
      if (typeof warningCheck !== "function") return null;
      return warningCheck(row) || null;
    },
    [warningCheck]
  );

  const displayValue = multiple
    ? (selected?.length > 1
        ? `${selected.length} ${label} selected`
        : selected?.length === 1
        ? selected[0][name]
        : "")
    : selected?.[name] || "";

  const isSelected = (row) => {
    if (!multiple) {
      return selected?.id === row.id;
    }

    return (selected || []).some((x) => x.id === row.id);
  };

  // Whether every record matching the current search/filter is currently selected
  const isAllSelected =
    multiple && totalRecord > 0 && (selected?.length || 0) === totalRecord;

  const isPartiallySelected =
    multiple && (selected?.length || 0) > 0 && !isAllSelected;

  const handleSelectAll = async () => {
    // Toggle off: if everything is already selected, clicking again clears selection
    if (isAllSelected) {
      setSelected([]);
      getData?.([]);
      return;
    }

    setSelectAllLoading(true);

    try {
      const pageSize = 1000;
      const requests = [];

      for (let pageOffset = 0; pageOffset < totalRecord; pageOffset += pageSize) {
        const payload = new FilterTableBuilder()
          .setPaging(pageOffset, pageSize)
          .setOrder([name], true);

        if (search) {
          payload.like(name, search);
        }

        if (filter?.length) {
          filter.forEach(f =>
            payload.where(
              f.logic_operator || "=",
              f.name,
              f.value,
              f.operator || "AND",
              f.value1 || null,
              f.table_name || null
            )
          );
        }

        joins.forEach(join => {
          payload.addJoin(join.table, join.columns);
        });

        requests.push(
          apiRequest.search(
            url,
            payload.build(),
            {
              headers: headersRequest,
            },
            isApiGo
          )
        );
      }

      const responses = await Promise.all(requests);

      const allRows = responses.flatMap(res => res.data || []);

      setSelected(allRows);
      getData?.(allRows);
    } catch (err) {
      console.error("Select All Error:", err);
    } finally {
      setSelectAllLoading(false);
    }
  };

  return (
    <>
      <TextField
        id={id}
        label={label}
        value={displayValue}
        fullWidth
        required={required}
        disabled={disabled}
        size={size}
        helperText={helperText}
        error={!!error}
        onClick={() => !disabled && setOpen(true)}
        sx={{
          ...customSxTextField,
          '& .MuiOutlinedInput-root.Mui-error .MuiOutlinedInput-notchedOutline': {
            borderColor: 'error.main',
          }
        }}
        slotProps={{
          input: {
            endAdornment: selected && (
              <InputAdornment position="end">
                <IconButton 
                  size="small"  
                  onClick={(e) => {
                    e.stopPropagation();
                    handleClear();
                  }}>
                  <ClearIcon sx={{ fontSize: 16 }} />
                </IconButton>
              </InputAdornment>
            )
          },
          formHelperText: {
            sx: {
              marginLeft: 0,
            }
          }
        }}
      />

      <Dialog open={open} onClose={() => setOpen(false)} maxWidth="sm" fullWidth>
        <DialogTitle sx={{ fontSize: 14 }}>Search {label}</DialogTitle>
        <DialogContent 
          onScroll={handleScroll} 
          sx={{
            '& .MuiTypography-root': {
              fontSize: 14,
            },
            '& .MuiInputBase-input': {
              fontSize: 14,
            },
            '& .MuiInputLabel-root': {
              fontSize: 14,
            },
            '& .MuiButton-root': {
              fontSize: 14,
            },
          }}
        >
          <TextField
            fullWidth
            autoFocus
            placeholder={`Search ${label}`}
            size="small"
            sx={{ my: 2, position: 'sticky', top: 0, zIndex: 10, bgcolor: 'background.paper' }}
            onChange={(e) => {
              const val = e.target.value;
              setSearch(val);
              debouncedFetch(val);
            }}
          />

          <List disablePadding>
            <>            
              {multiple && rows.length > 0 && (
                <ListItemButton
                  onClick={handleSelectAll}
                  disabled={selectAllLoading || totalRecord === 0}
                  sx={{ fontSize: 14 }}
                >
                  <ListItemIcon sx={{ minWidth: 36 }}>
                    {selectAllLoading ? (
                      <CircularProgress size={18} />
                    ) : (
                      <Checkbox
                        edge="start"
                        checked={isAllSelected}
                        indeterminate={isPartiallySelected}
                        tabIndex={-1}
                        disableRipple
                      />
                    )}
                  </ListItemIcon>
                  <ListItemText
                    primary={
                      selectAllLoading
                        ? "Selecting all..."
                        : isAllSelected
                        ? "Unselect All"
                        : "Select All"
                    }
                  />
                </ListItemButton>
              )}

              {rows.map((row, i) => {
                const warning = getRowWarning(row);

                return (
                  <ListItemButton
                    key={`${row.id}-${i}`}
                    onClick={() => handleSelect(row)}
                    disabled={selectAllLoading}
                  >
                    {multiple && (
                      <Checkbox checked={isSelected(row)} />
                    )}

                    <ListItemText
                      primary={
                        <Typography
                          component="span"
                          sx={{
                            fontSize: 14,
                            color: warning ? "error.main" : "text.primary",
                          }}
                        >
                          {row[name]}
                          {warning && (
                            <Typography
                              component="span"
                              sx={{ fontSize: 12, color: "error.main", ml: 0.5 }}
                            >
                              {" "}| {warning}
                            </Typography>
                          )}
                        </Typography>
                      }
                      secondary={row.join?.company_name}
                    />
                  </ListItemButton>
                );
              })}
              
              {loading && (
                <Typography variant="caption" sx={{ display: 'block', textAlign: 'center', p: 1 }}>
                  Loading more...
                </Typography>
              )}
            </>
          </List>

          {!loading && rows.length === 0 && (
            <Typography sx={{ textAlign: "center", fontSize: 12, color: "text.secondary", py: 3 }}>
              No Data
            </Typography>
          )}
        </DialogContent>

        <DialogActions>
          <Button onClick={handleClear} disabled={selectAllLoading}>Clear</Button>
          <Button onClick={() => setOpen(false)}>Cancel</Button>
          <Button
            onClick={() => {
              getData?.(selected ?? (multiple ? [] : null));
              setOpen(false);
            }}
            variant="contained"
            disabled={selectAllLoading}
          >
            Save
          </Button>
        </DialogActions>
      </Dialog>
    </>
  );
}