"use client";

import { useEffect, useState } from "react";

import {
  useListAgentsApiV1AgentsGet,
  type listAgentsApiV1AgentsGetResponse,
} from "@/api/generated/agents/agents";
import { ApiError } from "@/api/mutator";
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
} from "@/components/ui/dialog";
import { Button } from "@/components/ui/button";
import { Textarea } from "@/components/ui/textarea";
import type { ForgejoIssue, AssignIssueAgentResponse } from "@/lib/api-forgejo";
import { assignIssueToAgent, getLinkedBoardsForRepository } from "@/lib/api-forgejo";

type LinkedBoard = { id: string; name: string };

type AssignIssueAgentDialogProps = {
  issue: ForgejoIssue | null;
  repositoryName: string;
  open: boolean;
  onOpenChange: (open: boolean) => void;
  onSuccess: (result: AssignIssueAgentResponse) => void;
};

export function AssignIssueAgentDialog({
  issue,
  repositoryName,
  open,
  onOpenChange,
  onSuccess,
}: AssignIssueAgentDialogProps) {
  const [boardId, setBoardId] = useState("");
  const [agentId, setAgentId] = useState("");
  const [priority, setPriority] = useState("medium");
  const [instructions, setInstructions] = useState("");
  const [startImmediately, setStartImmediately] = useState(true);
  const [isSubmitting, setIsSubmitting] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [linkedBoards, setLinkedBoards] = useState<LinkedBoard[]>([]);
  const [boardsLoading, setBoardsLoading] = useState(false);

  // Fetch only boards linked to this issue's repository — prevents picking a
  // board that the backend will reject with "not linked to any board".
  useEffect(() => {
    if (!open || !issue) return;
    let cancelled = false;
    setBoardsLoading(true);
    setLinkedBoards([]);
    setBoardId("");
    getLinkedBoardsForRepository(issue.repository_id)
      .then((boards) => {
        if (cancelled) return;
        setLinkedBoards(boards);
        if (boards.length === 1) setBoardId(boards[0].id);
      })
      .catch(() => {
        if (!cancelled) setLinkedBoards([]);
      })
      .finally(() => {
        if (!cancelled) setBoardsLoading(false);
      });
    return () => { cancelled = true; };
  }, [open, issue]);

  const agentsQuery = useListAgentsApiV1AgentsGet<
    listAgentsApiV1AgentsGetResponse,
    ApiError
  >(
    { board_id: boardId || undefined, limit: 200 },
    { query: { enabled: open && !!boardId, refetchOnMount: "always" } },
  );

  const agents =
    agentsQuery.data?.status === 200
      ? (agentsQuery.data.data.items ?? [])
      : [];

  useEffect(() => {
    if (!open) {
      setBoardId("");
      setAgentId("");
      setPriority("medium");
      setInstructions("");
      setStartImmediately(true);
      setError(null);
    }
  }, [open]);

  useEffect(() => {
    setAgentId("");
  }, [boardId]);

  if (!issue) return null;

  const noLinkedBoards = !boardsLoading && linkedBoards.length === 0;

  const handleSubmit = async () => {
    if (!boardId) return;
    setIsSubmitting(true);
    setError(null);
    try {
      const result = await assignIssueToAgent(issue.id, {
        board_id: boardId,
        assigned_agent_id: agentId || undefined,
        priority,
        start_immediately: startImmediately,
        status: startImmediately && agentId ? "in_progress" : "inbox",
        instructions: instructions.trim() || undefined,
      });
      onSuccess(result);
      onOpenChange(false);
    } catch (err) {
      setError(err instanceof Error ? err.message : "Failed to assign agent");
    } finally {
      setIsSubmitting(false);
    }
  };

  const toggleSwitch = (
    value: boolean,
    setter: (v: boolean) => void,
    disabled: boolean,
  ) => (
    <button
      type="button"
      role="switch"
      aria-checked={value}
      onClick={() => !disabled && setter(!value)}
      disabled={disabled}
      className={`mt-0.5 inline-flex h-6 w-11 shrink-0 items-center rounded-full border transition ${
        value
          ? "border-emerald-600 bg-emerald-600"
          : "border-[color:var(--border)] bg-[color:var(--surface-muted)]"
      } ${disabled ? "cursor-not-allowed opacity-60" : "cursor-pointer"}`}
    >
      <span
        className={`inline-block h-5 w-5 rounded-full bg-[color:var(--surface)] shadow-sm transition ${
          value ? "translate-x-5" : "translate-x-0.5"
        }`}
      />
    </button>
  );

  return (
    <Dialog
      open={open}
      onOpenChange={(next) => {
        if (!isSubmitting) onOpenChange(next);
      }}
    >
      <DialogContent className="max-w-lg">
        <DialogHeader>
          <DialogTitle>Assign to agent</DialogTitle>
          <DialogDescription>
            Create a Pipeline task for{" "}
            <span className="font-mono font-semibold text-strong">
              {repositoryName}#{issue.forgejo_issue_number}
            </span>{" "}
            and assign an agent to work on it.
          </DialogDescription>
        </DialogHeader>

        <div className="space-y-4">
          <div className="rounded-xl border border-[color:var(--border)] bg-[color:var(--surface-muted)] px-3 py-2">
            <p className="truncate text-sm font-medium text-strong">
              {issue.title}
            </p>
          </div>

          {noLinkedBoards ? (
            <div className="rounded-xl border border-[color:rgba(234,179,8,0.4)] bg-[color:rgba(234,179,8,0.08)] p-4 text-sm">
              <p className="font-semibold text-[color:var(--warning,#ca8a04)]">
                Repository not linked to any board
              </p>
              <p className="mt-1 text-muted">
                Before you can assign an agent, link{" "}
                <span className="font-medium text-strong">{repositoryName}</span>{" "}
                to a board in{" "}
                <span className="font-medium text-strong">
                  Board Settings → Git Repositories
                </span>
                .
              </p>
            </div>
          ) : (
            <>
              <div className="space-y-1.5">
                <label className="text-sm font-medium text-strong">
                  Board <span className="text-[color:var(--danger)]">*</span>
                </label>
                <select
                  value={boardId}
                  onChange={(e) => setBoardId(e.target.value)}
                  disabled={isSubmitting || boardsLoading}
                  className="w-full rounded-xl border border-[color:var(--border)] bg-[color:var(--surface)] px-3 py-2 text-sm text-strong focus:outline-none focus:ring-2 focus:ring-[color:var(--accent)]"
                >
                  {boardsLoading ? (
                    <option>Loading boards…</option>
                  ) : (
                    <>
                      {linkedBoards.length > 1 && (
                        <option value="">Select a board…</option>
                      )}
                      {linkedBoards.map((b) => (
                        <option key={b.id} value={b.id}>
                          {b.name}
                        </option>
                      ))}
                    </>
                  )}
                </select>
              </div>

              <div className="space-y-1.5">
                <label className="text-sm font-medium text-strong">
                  Agent{" "}
                  <span className="text-xs font-normal text-muted">
                    (optional — leaves task unassigned if blank)
                  </span>
                </label>
                <select
                  value={agentId}
                  onChange={(e) => setAgentId(e.target.value)}
                  disabled={isSubmitting || !boardId || agentsQuery.isLoading}
                  className="w-full rounded-xl border border-[color:var(--border)] bg-[color:var(--surface)] px-3 py-2 text-sm text-strong focus:outline-none focus:ring-2 focus:ring-[color:var(--accent)]"
                >
                  <option value="">Unassigned</option>
                  {agentsQuery.isLoading ? (
                    <option disabled>Loading agents…</option>
                  ) : (
                    agents.map((a) => (
                      <option key={a.id} value={a.id}>
                        {a.name}
                        {a.is_board_lead ? " (lead)" : ""}
                      </option>
                    ))
                  )}
                </select>
              </div>

              <div className="space-y-1.5">
                <label className="text-sm font-medium text-strong">Priority</label>
                <select
                  value={priority}
                  onChange={(e) => setPriority(e.target.value)}
                  disabled={isSubmitting}
                  className="w-full rounded-xl border border-[color:var(--border)] bg-[color:var(--surface)] px-3 py-2 text-sm text-strong focus:outline-none focus:ring-2 focus:ring-[color:var(--accent)]"
                >
                  <option value="low">Low</option>
                  <option value="medium">Medium</option>
                  <option value="high">High</option>
                  <option value="critical">Critical</option>
                </select>
              </div>

              <div className="space-y-1.5">
                <label className="text-sm font-medium text-strong">
                  Instructions{" "}
                  <span className="text-xs font-normal text-muted">(optional)</span>
                </label>
                <Textarea
                  value={instructions}
                  onChange={(e) => setInstructions(e.target.value)}
                  disabled={isSubmitting}
                  rows={3}
                  placeholder="Additional context or instructions for the agent…"
                  className="resize-none text-sm"
                />
              </div>

              {agentId ? (
                <div className="flex items-center gap-3">
                  {toggleSwitch(startImmediately, setStartImmediately, isSubmitting)}
                  <span className="space-y-0.5">
                    <span className="block text-sm font-medium text-strong">
                      Start immediately
                    </span>
                    <span className="block text-xs text-muted">
                      Set task to{" "}
                      <span className="font-mono">in_progress</span> on assign.
                    </span>
                  </span>
                </div>
              ) : null}
            </>
          )}
        </div>

        {error ? (
          <div className="rounded-lg border border-[color:rgba(248,113,113,0.35)] bg-[color:rgba(248,113,113,0.08)] p-3 text-xs text-[color:var(--danger)]">
            {error}
          </div>
        ) : null}

        <DialogFooter>
          <Button
            variant="outline"
            onClick={() => onOpenChange(false)}
            disabled={isSubmitting}
          >
            Cancel
          </Button>
          {!noLinkedBoards && (
            <Button
              onClick={handleSubmit}
              disabled={isSubmitting || !boardId}
            >
              {isSubmitting
                ? "Assigning…"
                : agentId
                  ? "Assign Agent"
                  : "Create Task"}
            </Button>
          )}
        </DialogFooter>
      </DialogContent>
    </Dialog>
  );
}
