const { store } = require("../mock/store");
const { reportError } = require("../lib/report-error");

// Bus-line repository methods (DEV_MOCK mode). Each mirrors the original
// handler's `if (DEV_MOCK) { ... }` branch verbatim and returns
// { statusCode, body }. The original reorder/delete handlers acquired a
// db.pool.connect() before the mock branch; the mock implementation below
// intentionally skips that so mock-only deletion/reorder work without a
// database (documented improvement).

async function listLineStops(req) {
  try {
    const { busLineId } = req.params;
    const stops = store.routeStops
      .filter((rs) => String(rs.busLineId) === String(busLineId))
      .sort((a, b) => a.stopOrder - b.stopOrder)
      .map((rs) => ({
        id: rs.id,
        order: rs.stopOrder,
        name: rs.name,
        latitude: rs.latitude,
        longitude: rs.longitude,
        estimatedArrivalMinutes: rs.estimatedArrivalMinutes,
      }));
    return { statusCode: 200, body: { stops } };
  } catch (err) {
    console.error(err);
    reportError({ partofservice: `${req.method} ${req.originalUrl}`, error: err.stack || err.message });
    return { statusCode: 500, body: { error: "internal_error", details: err.message } };
  }
}

async function listLines(req) {
  try {
    return {
      statusCode: 200,
      body: {
        busLines: store.busLines
          .slice()
          .sort((a, b) => a.lineNumber - b.lineNumber),
      },
    };
  } catch (err) {
    console.error(err);
    reportError({ partofservice: `${req.method} ${req.originalUrl}`, error: err.stack || err.message });
    return { statusCode: 500, body: { error: "internal_error", details: err.message } };
  }
}

async function createLine(req) {
  try {
    const {
      lineNumber,
      startStop,
      endStop,
      estimatedDurationMinutes,
      description,
    } = req.body;

    if (
      lineNumber === undefined ||
      !startStop ||
      !endStop ||
      estimatedDurationMinutes === undefined
    ) {
      return { statusCode: 400, body: { error: "missing_required_fields" } };
    }

    const busLine = {
      id: store.nextBusLineId++,
      lineNumber: Number(lineNumber),
      startStop,
      endStop,
      estimatedDurationMinutes: Number(estimatedDurationMinutes),
      description: description || "",
      createdAt: new Date().toISOString(),
      updatedAt: new Date().toISOString(),
    };
    store.busLines.push(busLine);
    return { statusCode: 201, body: { busLine } };
  } catch (err) {
    console.error(err);
    reportError({ partofservice: `${req.method} ${req.originalUrl}`, error: err.stack || err.message });
    return { statusCode: 500, body: { error: "internal_error", details: err.message } };
  }
}

async function updateLine(req) {
  try {
    const { busLineId } = req.params;
    const {
      lineNumber,
      startStop,
      endStop,
      estimatedDurationMinutes,
      description,
    } = req.body;

    const existing = store.busLines.find(
      (line) => String(line.id) === String(busLineId),
    );
    if (!existing)
      return { statusCode: 404, body: { error: "bus_line_not_found" } };
    if (lineNumber !== undefined) existing.lineNumber = Number(lineNumber);
    if (startStop !== undefined) existing.startStop = startStop;
    if (endStop !== undefined) existing.endStop = endStop;
    if (estimatedDurationMinutes !== undefined)
      existing.estimatedDurationMinutes = Number(estimatedDurationMinutes);
    if (description !== undefined) existing.description = description;
    existing.updatedAt = new Date().toISOString();
    return { statusCode: 200, body: { busLine: existing } };
  } catch (err) {
    console.error(err);
    reportError({ partofservice: `${req.method} ${req.originalUrl}`, error: err.stack || err.message });
    return { statusCode: 500, body: { error: "internal_error", details: err.message } };
  }
}

async function listLineStopsDetailed(req) {
  try {
    const { busLineId } = req.params;
    if (!busLineId || !Number.isFinite(Number(busLineId))) {
      return { statusCode: 400, body: { error: "invalid_bus_line_id" } };
    }

    const stops = store.routeStops
      .filter((rs) => String(rs.busLineId) === String(busLineId))
      .sort((a, b) => a.stopOrder - b.stopOrder)
      .map((rs) => ({
        id: rs.id,
        busLineId: rs.busLineId,
        stopId: rs.stopId,
        stopOrder: rs.stopOrder,
        estimatedArrivalMinutes: rs.estimatedArrivalMinutes,
        name: rs.name,
        latitude: rs.latitude,
        longitude: rs.longitude,
      }));
    return { statusCode: 200, body: { routeStops: stops } };
  } catch (err) {
    console.error(err);
    reportError({ partofservice: `${req.method} ${req.originalUrl}`, error: err.stack || err.message });
    return { statusCode: 500, body: { error: "internal_error", details: err.message } };
  }
}

async function addLineStop(req) {
  try {
    const { busLineId } = req.params;
    const { stopId, stopOrder, estimatedArrivalMinutes } = req.body;

    if (!stopId || stopOrder === undefined) {
      return { statusCode: 400, body: { error: "missing_required_fields" } };
    }

    const stop = store.stops.find((s) => String(s.id) === String(stopId));
    const routeStop = {
      id: store.nextRouteStopId++,
      busLineId: Number(busLineId),
      stopId: Number(stopId),
      stopOrder: Number(stopOrder),
      estimatedArrivalMinutes: estimatedArrivalMinutes ?? null,
      createdAt: new Date().toISOString(),
      updatedAt: new Date().toISOString(),
      name: stop ? stop.name : `stop-${stopId}`,
      latitude: stop ? stop.latitude : 0,
      longitude: stop ? stop.longitude : 0,
    };
    // remove existing with same busLineId & stopOrder
    store.routeStops = store.routeStops.filter(
      (rs) =>
        !(
          rs.busLineId === routeStop.busLineId &&
          rs.stopOrder === routeStop.stopOrder
        ),
    );
    store.routeStops.push(routeStop);
    return { statusCode: 201, body: { routeStop } };
  } catch (err) {
    console.error(err);
    reportError({ partofservice: `${req.method} ${req.originalUrl}`, error: err.stack || err.message });
    return { statusCode: 500, body: { error: "internal_error", details: err.message } };
  }
}

async function reorderLineStops(req) {
  try {
    const { busLineId } = req.params;
    const { routeStopIds } = req.body || {};

    if (!Array.isArray(routeStopIds) || routeStopIds.length === 0) {
      return { statusCode: 400, body: { error: "routeStopIds array required" } };
    }

    const normalizedIds = routeStopIds
      .map((id) => Number(id))
      .filter((id) => Number.isFinite(id));
    if (normalizedIds.length !== routeStopIds.length) {
      return { statusCode: 400, body: { error: "routeStopIds must contain only numeric ids" } };
    }

    const busLineStops = store.routeStops
      .filter((rs) => String(rs.busLineId) === String(busLineId))
      .sort((a, b) => a.stopOrder - b.stopOrder);

    const idSet = new Set(busLineStops.map((rs) => Number(rs.id)));
    const sameCount = busLineStops.length === normalizedIds.length;
    const sameIds = sameCount && normalizedIds.every((id) => idSet.has(id));
    if (!sameIds) {
      return { statusCode: 400, body: { error: "routeStopIds must match current bus line stops" } };
    }

    const updated = normalizedIds.map((routeStopId, index) => {
      const stop = store.routeStops.find(
        (rs) =>
          Number(rs.id) === routeStopId &&
          String(rs.busLineId) === String(busLineId),
      );
      if (!stop) return null;
      stop.stopOrder = index + 1;
      stop.updatedAt = new Date().toISOString();
      return stop;
    });

    if (updated.some((item) => !item)) {
      return { statusCode: 400, body: { error: "routeStopIds must match current bus line stops" } };
    }

    store.routeStops = store.routeStops.map((routeStop) => {
      const reordered = updated.find((item) => item.id === routeStop.id);
      return reordered || routeStop;
    });

    return { statusCode: 200, body: { routeStops: updated } };
  } catch (err) {
    console.error(err);
    reportError({ partofservice: `${req.method} ${req.originalUrl}`, error: err.stack || err.message });
    return { statusCode: 500, body: { error: "internal_error", details: err.message } };
  }
}

async function deleteLine(req) {
  try {
    const { busLineId } = req.params;

    if (!busLineId || !Number.isFinite(Number(busLineId))) {
      return { statusCode: 400, body: { error: "invalid_bus_line_id" } };
    }

    const lineIndex = store.busLines.findIndex(
      (bl) => Number(bl.id) === Number(busLineId),
    );
    if (lineIndex === -1) {
      return { statusCode: 404, body: { error: "bus_line_not_found" } };
    }
    const deletedLine = store.busLines.splice(lineIndex, 1)[0];
    // Also delete route_stops for this line
    store.routeStops = store.routeStops.filter(
      (rs) => String(rs.busLineId) !== String(busLineId),
    );
    return { statusCode: 200, body: { success: true, busLine: deletedLine } };
  } catch (err) {
    console.error(err);
    reportError({ partofservice: `${req.method} ${req.originalUrl}`, error: err.stack || err.message });
    return { statusCode: 500, body: { error: "internal_error", details: err.message } };
  }
}

async function deleteLineStop(req) {
  try {
    const { busLineId, routeStopId } = req.params;

    if (!busLineId || !Number.isFinite(Number(busLineId))) {
      return { statusCode: 400, body: { error: "invalid_bus_line_id" } };
    }

    if (!routeStopId || !Number.isFinite(Number(routeStopId))) {
      return { statusCode: 400, body: { error: "invalid_route_stop_id" } };
    }

    const index = store.routeStops.findIndex(
      (rs) =>
        Number(rs.id) === Number(routeStopId) &&
        String(rs.busLineId) === String(busLineId),
    );
    if (index === -1) {
      return { statusCode: 404, body: { error: "route_stop_not_found" } };
    }
    const deletedRouteStop = store.routeStops.splice(index, 1)[0];
    return { statusCode: 200, body: { success: true, routeStop: deletedRouteStop } };
  } catch (err) {
    console.error(err);
    reportError({ partofservice: `${req.method} ${req.originalUrl}`, error: err.stack || err.message });
    return { statusCode: 500, body: { error: "internal_error", details: err.message } };
  }
}

module.exports = {
  listLineStops,
  listLines,
  createLine,
  updateLine,
  listLineStopsDetailed,
  addLineStop,
  reorderLineStops,
  deleteLine,
  deleteLineStop,
};