import { TRPCError } from "@trpc/server";
import type { Allocation } from "@capakraken/shared";
import {
  formatHolidayOverlays,
  loadTimelineHolidayOverlays,
  summarizeHolidayOverlays,
} from "./timeline-holiday-read.js";
import {
  anonymizeResourceOnEntry,
  createTimelineDateRange,
  fmtDate,
  rangesOverlap,
  summarizeTimelineEntries,
  toDate,
} from "./timeline-read-shared.js";

type TimelineAnonymizationDirectory = Parameters<typeof anonymizeResourceOnEntry>[1];

export interface ResolveTimelineProjectContextPeriodInput {
  requestedStartDate?: string | undefined;
  requestedEndDate?: string | undefined;
  durationDays?: number | undefined;
  projectStartDate?: Date | null | undefined;
  projectEndDate?: Date | null | undefined;
  firstAssignmentStartDate?: Date | string | null | undefined;
  firstDemandStartDate?: Date | string | null | undefined;
}

export function resolveTimelineProjectContextPeriod(
  input: ResolveTimelineProjectContextPeriodInput,
) {
  const startDate = input.requestedStartDate
    ? createTimelineDateRange({
        startDate: input.requestedStartDate,
        durationDays: 1,
      }).startDate
    : input.projectStartDate
      ?? (input.firstAssignmentStartDate ? toDate(input.firstAssignmentStartDate) : null)
      ?? (input.firstDemandStartDate ? toDate(input.firstDemandStartDate) : null)
      ?? createTimelineDateRange({ durationDays: 1 }).startDate;

  const endDate = input.requestedEndDate
    ? createTimelineDateRange({
        startDate: fmtDate(startDate) ?? undefined,
        endDate: input.requestedEndDate,
      }).endDate
    : input.projectEndDate
      ?? createTimelineDateRange({
          startDate: fmtDate(startDate) ?? undefined,
          durationDays: input.durationDays ?? 21,
        }).endDate;

  if (endDate < startDate) {
    throw new TRPCError({
      code: "BAD_REQUEST",
      message: "endDate must be on or after startDate.",
    });
  }

  return { startDate, endDate };
}

export interface TimelineProjectAssignmentConflict {
  assignmentId: string;
  resourceId: string;
  resourceName: string | null;
  startDate: string | null;
  endDate: string | null;
  hoursPerDay: number;
  overlapCount: number;
  crossProjectOverlapCount: number;
  overlaps: Array<{
    id: string;
    projectId: string | null;
    projectName: string | null;
    projectShortCode: string | null;
    startDate: string | null;
    endDate: string | null;
    hoursPerDay: number;
    status: string;
    sameProject: boolean;
  }>;
}

export function buildTimelineProjectAssignmentConflicts(input: {
  projectId: string;
  assignments: Array<{
    id: string;
    resourceId: string | null;
    resource?: { displayName?: string | null } | null;
    startDate: Date | string;
    endDate: Date | string;
    hoursPerDay: number;
  }>;
  allResourceAllocations: Array<{
    id: string;
    resourceId: string | null;
    projectId: string | null;
    project?: { name?: string | null; shortCode?: string | null } | null;
    startDate: Date | string;
    endDate: Date | string;
    hoursPerDay: number;
    status: string;
  }>;
}): TimelineProjectAssignmentConflict[] {
  return input.assignments
    .filter((assignment) => assignment.resourceId && assignment.resource)
    .map((assignment) => {
      const overlaps = input.allResourceAllocations
        .filter((booking) => (
          booking.resourceId === assignment.resourceId
          && booking.id !== assignment.id
          && rangesOverlap(
            toDate(booking.startDate),
            toDate(booking.endDate),
            toDate(assignment.startDate),
            toDate(assignment.endDate),
          )
        ))
        .map((booking) => ({
          id: booking.id,
          projectId: booking.projectId,
          projectName: booking.project?.name ?? null,
          projectShortCode: booking.project?.shortCode ?? null,
          startDate: fmtDate(toDate(booking.startDate)),
          endDate: fmtDate(toDate(booking.endDate)),
          hoursPerDay: booking.hoursPerDay,
          status: booking.status,
          sameProject: booking.projectId === input.projectId,
        }));

      return {
        assignmentId: assignment.id,
        resourceId: assignment.resourceId!,
        resourceName: assignment.resource?.displayName ?? null,
        startDate: fmtDate(toDate(assignment.startDate)),
        endDate: fmtDate(toDate(assignment.endDate)),
        hoursPerDay: assignment.hoursPerDay,
        overlapCount: overlaps.length,
        crossProjectOverlapCount: overlaps.filter((booking) => !booking.sameProject).length,
        overlaps,
      };
    });
}

export function buildTimelineProjectContextSummary(input: {
  allocations: Array<{ projectId: string | null; resourceId: string | null }>;
  demands: Array<{ projectId: string | null }>;
  assignments: Array<{ projectId: string | null; resourceId: string | null }>;
  resourceIds: string[];
  allResourceAllocations: unknown[];
  assignmentConflicts: Array<{ crossProjectOverlapCount: number }>;
  holidayOverlays: ReturnType<typeof formatHolidayOverlays>;
}) {
  return {
    ...summarizeTimelineEntries({
      allocations: input.allocations,
      demands: input.demands,
      assignments: input.assignments,
    }),
    resourceIds: input.resourceIds.length,
    allResourceAllocationCount: input.allResourceAllocations.length,
    conflictedAssignmentCount: input.assignmentConflicts.filter(
      (item) => item.crossProjectOverlapCount > 0,
    ).length,
    ...summarizeHolidayOverlays(input.holidayOverlays),
  };
}

export function buildTimelineShiftValidationBookings(
  bookings: Array<{
    id: string;
    resourceId: string | null;
    projectId: string | null;
    startDate: Date;
    endDate: Date;
    hoursPerDay: number;
    status: string;
  }>,
) {
  return bookings
    .filter(
      (
        booking,
      ): booking is typeof booking & { resourceId: string; projectId: string } =>
        booking.resourceId !== null && booking.projectId !== null,
    )
    .map((booking) => ({
      id: booking.id,
      resourceId: booking.resourceId,
      projectId: booking.projectId,
      startDate: booking.startDate,
      endDate: booking.endDate,
      hoursPerDay: booking.hoursPerDay,
      status: booking.status,
    }));
}

export function buildTimelineBudgetStatusAllocations(
  bookings: Array<{
    status: string;
    dailyCostCents: number;
    startDate: Date;
    endDate: Date;
    hoursPerDay: number;
  }>,
): Pick<
  Allocation,
  "status" | "dailyCostCents" | "startDate" | "endDate" | "hoursPerDay"
>[] {
  return bookings.map((booking) => ({
    status: booking.status as Allocation["status"],
    dailyCostCents: booking.dailyCostCents,
    startDate: booking.startDate,
    endDate: booking.endDate,
    hoursPerDay: booking.hoursPerDay,
  }));
}

export function buildTimelineBudgetStatusResponse<TBudgetStatus extends object>(input: {
  project: {
    name: string;
    shortCode: string | null;
    budgetCents: number;
  };
  budgetStatus: TBudgetStatus;
  totalAllocations: number;
}): TBudgetStatus & {
  projectName: string;
  projectCode: string;
  totalAllocations: number;
  budgetCents: number;
} {
  return {
    ...input.budgetStatus,
    projectName: input.project.name,
    projectCode: input.project.shortCode ?? "",
    totalAllocations: input.totalAllocations,
    budgetCents: input.project.budgetCents,
  };
}

export function buildTimelineProjectContextResponse<
  TProject,
  TAllocation extends { resource?: { id: string } | null },
  TDemand,
  TAssignment extends { resource?: { id: string } | null },
  TBooking extends { resource?: { id: string } | null },
>(input: {
  project: TProject;
  allocations: TAllocation[];
  demands: TDemand[];
  assignments: TAssignment[];
  allResourceAllocations: TBooking[];
  resourceIds: string[];
  directory: TimelineAnonymizationDirectory;
}) {
  return {
    project: input.project,
    allocations: input.allocations.map((allocation) =>
      anonymizeResourceOnEntry(allocation, input.directory),
    ),
    demands: input.demands,
    assignments: input.assignments.map((assignment) =>
      anonymizeResourceOnEntry(assignment, input.directory),
    ),
    allResourceAllocations: input.allResourceAllocations.map((allocation) =>
      anonymizeResourceOnEntry(allocation, input.directory),
    ),
    resourceIds: input.resourceIds,
  };
}

export function buildTimelineProjectContextDetailResponse<
  TProject,
  TAllocation extends { projectId: string | null; resourceId: string | null; resource?: { id: string } | null },
  TDemand extends { projectId: string | null },
  TAssignment extends { projectId: string | null; resourceId: string | null; resource?: { id: string } | null },
  TBooking extends { resource?: { id: string } | null },
  TConflict extends { crossProjectOverlapCount: number },
>(input: {
  project: TProject;
  period: { startDate: Date; endDate: Date };
  allocations: TAllocation[];
  demands: TDemand[];
  assignments: TAssignment[];
  allResourceAllocations: TBooking[];
  resourceIds: string[];
  assignmentConflicts: TConflict[];
  holidayOverlays: ReturnType<typeof formatHolidayOverlays>;
  directory: TimelineAnonymizationDirectory;
}) {
  const base = buildTimelineProjectContextResponse({
    project: input.project,
    allocations: input.allocations,
    demands: input.demands,
    assignments: input.assignments,
    allResourceAllocations: input.allResourceAllocations,
    resourceIds: input.resourceIds,
    directory: input.directory,
  });

  return {
    ...base,
    period: {
      startDate: fmtDate(input.period.startDate),
      endDate: fmtDate(input.period.endDate),
    },
    summary: buildTimelineProjectContextSummary({
      allocations: input.allocations,
      demands: input.demands,
      assignments: input.assignments,
      resourceIds: input.resourceIds,
      allResourceAllocations: input.allResourceAllocations,
      assignmentConflicts: input.assignmentConflicts,
      holidayOverlays: input.holidayOverlays,
    }),
    assignmentConflicts: input.assignmentConflicts,
    holidayOverlays: input.holidayOverlays,
  };
}

export async function loadTimelineProjectContextDetailArtifacts(
  db: Parameters<typeof loadTimelineHolidayOverlays>[0],
  input: {
    projectId: string;
    requestedStartDate?: string | undefined;
    requestedEndDate?: string | undefined;
    durationDays?: number | undefined;
    projectStartDate?: Date | null | undefined;
    projectEndDate?: Date | null | undefined;
    firstAssignmentStartDate?: Date | string | null | undefined;
    firstDemandStartDate?: Date | string | null | undefined;
    assignments: Array<{
      id: string;
      resourceId: string | null;
      resource?: { displayName?: string | null } | null;
      startDate: Date | string;
      endDate: Date | string;
      hoursPerDay: number;
    }>;
    allResourceAllocations: Array<{
      id: string;
      resourceId: string | null;
      projectId: string | null;
      project?: { name?: string | null; shortCode?: string | null } | null;
      startDate: Date | string;
      endDate: Date | string;
      hoursPerDay: number;
      status: string;
    }>;
    resourceIds: string[];
  },
) {
  const period = resolveTimelineProjectContextPeriod({
    requestedStartDate: input.requestedStartDate,
    requestedEndDate: input.requestedEndDate,
    durationDays: input.durationDays,
    projectStartDate: input.projectStartDate,
    projectEndDate: input.projectEndDate,
    firstAssignmentStartDate: input.firstAssignmentStartDate,
    firstDemandStartDate: input.firstDemandStartDate,
  });

  const holidayOverlays = input.resourceIds.length > 0
    ? formatHolidayOverlays(await loadTimelineHolidayOverlays(db, {
        startDate: period.startDate,
        endDate: period.endDate,
        resourceIds: input.resourceIds,
        projectIds: [input.projectId],
      }))
    : [];

  const assignmentConflicts = buildTimelineProjectAssignmentConflicts({
    projectId: input.projectId,
    assignments: input.assignments,
    allResourceAllocations: input.allResourceAllocations,
  });

  return {
    period,
    holidayOverlays,
    assignmentConflicts,
  };
}

export function buildTimelineShiftPreviewDetailResponse<TPreview>(input: {
  project: {
    id: string;
    name: string;
    shortCode: string | null;
    status: string;
    responsiblePerson: string | null;
    startDate: Date;
    endDate: Date;
  };
  requestedShift: {
    newStartDate: Date;
    newEndDate: Date;
  };
  preview: TPreview;
}) {
  return {
    project: {
      id: input.project.id,
      name: input.project.name,
      shortCode: input.project.shortCode,
      status: input.project.status,
      responsiblePerson: input.project.responsiblePerson,
      startDate: fmtDate(input.project.startDate),
      endDate: fmtDate(input.project.endDate),
    },
    requestedShift: {
      newStartDate: fmtDate(input.requestedShift.newStartDate),
      newEndDate: fmtDate(input.requestedShift.newEndDate),
    },
    preview: input.preview,
  };
}