import { MessageSquare, X, ChevronDown } from "lucide-react";
import type { TaskDetail } from "../api";
import { Markdown } from "./Markdown";
import { Badge, statusVariant } from "@/components/ui/badge";
import { Button } from "@/components/ui/button";
import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
import { Separator } from "@/components/ui/separator";
import { ScrollArea } from "@/components/ui/scroll-area";
import {
  Collapsible,
  CollapsibleTrigger,
  CollapsibleContent,
} from "@/components/ui/collapsible";
import { cn } from "@/lib/utils";

interface Props {
  detail: TaskDetail | null;
  loading: boolean;
  error: string | null;
  onClose: () => void;
}

function fmtDuration(s: number | null): string {
  if (s == null) return "—";
  if (s < 60) return `${s.toFixed(1)}s`;
  if (s < 3600) return `${(s / 60).toFixed(1)}m`;
  return `${(s / 3600).toFixed(1)}h`;
}

function fmtCost(usd: number): string {
  return usd > 0 ? `$${usd.toFixed(4)}` : "—";
}

// Right-hand drawer: a task's journey through the pipeline (vertical timeline of
// task_transitions) plus Q&A, review verdicts, plan summary, and total spend.
export function TaskDrawer({ detail, loading, error, onClose }: Props) {
  if (!detail && !loading && !error) return null;

  const isWaiting = detail?.ok && detail.status === "waiting_human";
  const isClarifyGate =
    isWaiting && detail?.current_phase === "clarify";

  return (
    <section
      className="flex flex-col w-[380px] h-full bg-card border-l border-border"
      aria-label="task detail"
      role="complementary"
    >
      {/* Sticky header */}
      <div className="sticky top-0 z-10 flex items-center justify-between px-3 py-2 bg-card border-b border-border">
        <h2 className="text-sm font-semibold text-foreground">Task history</h2>
        <Button
          variant="ghost"
          size="icon"
          aria-label="Close detail"
          onClick={onClose}
          className="h-7 w-7"
        >
          <X className="h-4 w-4" />
        </Button>
      </div>

      {loading && (
        <div className="flex-1 flex items-center justify-center text-sm text-muted-foreground">
          Loading…
        </div>
      )}
      {error && (
        <div className="m-3 rounded-md bg-status-failed-bg text-status-failed text-sm px-3 py-2">
          {error}
        </div>
      )}

      {detail && detail.ok && (
        <ScrollArea className="flex-1">
          <div className="p-3 space-y-3">
            {/* Summary card */}
            <Card className="bg-background">
              <CardContent className="pt-3 pb-3 space-y-1.5">
                <p className="text-sm font-medium text-foreground leading-snug">
                  {detail.task}
                </p>
                <div className="flex items-center gap-2 flex-wrap">
                  <Badge variant={statusVariant(detail.status)}>
                    {detail.status}
                  </Badge>
                  <code className="text-xs font-mono text-muted-foreground">
                    {detail.short_id}
                  </code>
                  <span className="text-xs text-muted-foreground">
                    spend {fmtCost(detail.total_usd)}
                  </span>
                </div>
                {detail.partial && (
                  <p className="text-xs text-muted-foreground bg-muted rounded px-2 py-1">
                    Partial history — recorded since the v3 ledger; earlier
                    steps are reconstructed.
                  </p>
                )}
              </CardContent>
            </Card>

            {/* Gate panel — waiting_human informational only */}
            {isWaiting && (
              <Card className="bg-status-waiting-bg border border-status-waiting/30">
                <CardContent className="pt-3 pb-3">
                  <div className="flex items-start gap-2">
                    <MessageSquare className="h-4 w-4 mt-0.5 shrink-0 text-status-waiting" />
                    <div className="space-y-1 min-w-0">
                      <p className="text-sm font-semibold text-status-waiting">
                        Input requested
                      </p>
                      <p className="text-xs text-status-waiting/80 leading-snug">
                        {isClarifyGate
                          ? "The pipeline needs clarification before planning."
                          : "The pipeline is awaiting a human decision to proceed."}
                      </p>
                      <p className="text-xs font-medium text-status-waiting mt-1">
                        Answer in Slack{" "}
                        <span className="font-mono">#agent-team</span>
                      </p>
                    </div>
                  </div>
                </CardContent>
              </Card>
            )}

            {/* Timeline */}
            <div>
              <p className="text-xs font-semibold text-muted-foreground uppercase tracking-wide mb-2">
                Timeline
              </p>
              <ol className="relative space-y-0">
                {detail.timeline.map((step, i) => {
                  const open = step.exited_at == null;
                  const isLast = i === detail.timeline.length - 1;
                  return (
                    <li key={i} className="flex gap-2">
                      {/* Dot + connector */}
                      <div className="flex flex-col items-center">
                        <span
                          className={cn(
                            "mt-1 h-2 w-2 rounded-full shrink-0 border-2",
                            open
                              ? "bg-status-active border-status-active"
                              : "bg-muted border-border",
                          )}
                          aria-hidden
                        />
                        {!isLast && (
                          <span className="w-px flex-1 bg-border mt-0.5 mb-0.5 min-h-[12px]" />
                        )}
                      </div>

                      {/* Step body */}
                      <div className="pb-3 flex-1 min-w-0">
                        <div className="flex items-center justify-between gap-2">
                          <span className="text-sm font-medium text-foreground">
                            {step.to_phase}
                          </span>
                          <span
                            className={cn(
                              "text-xs shrink-0",
                              open
                                ? "text-status-active font-medium"
                                : "text-muted-foreground",
                            )}
                          >
                            {open ? "in progress" : fmtDuration(step.duration_s)}
                          </span>
                        </div>
                        <div className="flex items-center gap-2 mt-0.5 flex-wrap">
                          {step.entered_at && (
                            <span className="text-xs text-muted-foreground">
                              {step.entered_at}
                            </span>
                          )}
                          {step.status && (
                            <Badge variant={statusVariant(step.status)} className="text-[10px] py-0 px-1.5">
                              {step.status}
                            </Badge>
                          )}
                          {step.cost_usd > 0 && (
                            <span className="text-xs text-muted-foreground">
                              {fmtCost(step.cost_usd)}
                            </span>
                          )}
                          {step.note && (
                            <span className="text-xs text-muted-foreground italic">
                              {step.note}
                            </span>
                          )}
                        </div>
                      </div>
                    </li>
                  );
                })}
                {detail.timeline.length === 0 && (
                  <li className="text-sm text-muted-foreground py-2">
                    No transitions recorded.
                  </li>
                )}
              </ol>
            </div>

            {/* Q&A section */}
            {detail.qa_history.length > 0 && (
              <>
                <Separator />
                <CollapsibleSection
                  title={`Q&A (${detail.qa_history.length})`}
                  defaultOpen
                >
                  <QASection entries={detail.qa_history} />
                </CollapsibleSection>
              </>
            )}

            {/* Review verdicts */}
            {detail.review_verdicts.length > 0 && (
              <>
                <Separator />
                <CollapsibleSection
                  title={`Review verdicts (${detail.review_verdicts.length})`}
                  defaultOpen={true}
                >
                  <VerdictsSection entries={detail.review_verdicts} />
                </CollapsibleSection>
              </>
            )}

            {/* Plan */}
            {detail.plan && (
              <>
                <Separator />
                <CollapsibleSection title="Plan" defaultOpen={true}>
                  <PlanSection plan={detail.plan} />
                </CollapsibleSection>
              </>
            )}
          </div>
        </ScrollArea>
      )}

      {detail && !detail.ok && (
        <div className="m-3 rounded-md bg-status-failed-bg text-status-failed text-sm px-3 py-2">
          {detail.error ?? "Could not load task."}
        </div>
      )}
    </section>
  );
}

// Collapsible section wrapper used for Q&A / Verdicts / Plan
function CollapsibleSection({
  title,
  defaultOpen,
  children,
}: {
  title: string;
  defaultOpen: boolean;
  children: React.ReactNode;
}) {
  return (
    <Collapsible defaultOpen={defaultOpen}>
      <CollapsibleTrigger className="flex items-center justify-between w-full group">
        <span className="text-xs font-semibold text-muted-foreground uppercase tracking-wide">
          {title}
        </span>
        <ChevronDown className="h-3.5 w-3.5 text-muted-foreground transition-transform group-data-[state=open]:rotate-180" />
      </CollapsibleTrigger>
      <CollapsibleContent>
        <div className="mt-2">{children}</div>
      </CollapsibleContent>
    </Collapsible>
  );
}

function asText(v: unknown): string {
  return typeof v === "string" ? v : v == null ? "" : JSON.stringify(v, null, 2);
}

// Q&A: each entry is the answer text for a turn (a string), or an older
// {turn, question_id, answer} dict. Render each as a turn card with the answer
// as markdown so numbered sub-answers / bold render readably.
function QASection({ entries }: { entries: unknown[] }) {
  return (
    <div className="space-y-2">
      {entries.map((entry, i) => {
        const obj =
          entry && typeof entry === "object" ? (entry as Record<string, unknown>) : null;
        const turn = obj && "turn" in obj ? Number(obj.turn) : i;
        const answer = obj && "answer" in obj ? asText(obj.answer) : asText(entry);
        return (
          <Card key={i} className="bg-background">
            <CardHeader className="pb-1 pt-2 px-3">
              <CardTitle className="text-xs font-semibold text-muted-foreground">
                Turn {turn + 1}
              </CardTitle>
            </CardHeader>
            <CardContent className="pb-2 px-3 text-sm prose-sm">
              <Markdown>{answer}</Markdown>
            </CardContent>
          </Card>
        );
      })}
    </div>
  );
}

// Review verdicts: each {verdict, round_index, outcome, findings} → a card with a
// verdict badge + round + outcome header and the findings rendered as markdown.
function VerdictsSection({ entries }: { entries: unknown[] }) {
  return (
    <div className="space-y-2">
      {entries.map((entry, i) => {
        const v =
          entry && typeof entry === "object" ? (entry as Record<string, unknown>) : {};
        const verdict = asText(v.verdict) || "verdict";
        const round = "round_index" in v ? Number(v.round_index) : i + 1;
        const outcome = asText(v.outcome);
        const findings = asText(v.findings);
        return (
          <Card key={i} className="bg-background">
            <CardHeader className="pb-1 pt-2 px-3">
              <div className="flex items-center gap-2 flex-wrap">
                <span className="text-xs text-muted-foreground">
                  Round {round}
                </span>
                <Badge variant={statusVariant(verdict)}>
                  {verdict.replace(/_/g, " ")}
                </Badge>
                {outcome && (
                  <span className="text-xs text-muted-foreground">
                    {outcome.replace(/_/g, " ")}
                  </span>
                )}
              </div>
            </CardHeader>
            {findings && (
              <CardContent className="pb-2 px-3 text-sm prose-sm">
                <Markdown>{findings}</Markdown>
              </CardContent>
            )}
          </Card>
        );
      })}
    </div>
  );
}

// Plan: {summary, phases:[{name, steps:[...]}]} → summary (markdown) + a phase
// list with nested steps. Any extra scalar keys render as a small label/value
// list; an unrecognized shape falls back to a collapsed JSON view.
function PlanSection({ plan }: { plan: Record<string, unknown> }) {
  const summary = asText(plan.summary);
  const phases = Array.isArray(plan.phases) ? plan.phases : null;
  const extra = Object.entries(plan).filter(
    ([k, val]) =>
      k !== "summary" && k !== "phases" && (typeof val !== "object" || val === null),
  );

  if (!summary && !phases) {
    return (
      <pre className="text-xs bg-muted rounded p-2 overflow-auto font-mono">
        {JSON.stringify(plan, null, 2)}
      </pre>
    );
  }

  return (
    <div className="space-y-2">
      {summary && (
        <div className="text-sm prose-sm">
          <Markdown>{summary}</Markdown>
        </div>
      )}
      {phases && (
        <ol className="space-y-2">
          {phases.map((p, i) => {
            const ph =
              p && typeof p === "object" ? (p as Record<string, unknown>) : {};
            const name = asText(ph.name) || `Phase ${i + 1}`;
            const steps = Array.isArray(ph.steps) ? ph.steps : [];
            return (
              <li key={i}>
                <p className="text-xs font-semibold text-foreground mb-1">
                  {name}
                </p>
                {steps.length > 0 && (
                  <ul className="space-y-0.5 pl-3">
                    {steps.map((s, j) => (
                      <li
                        key={j}
                        className="text-xs text-muted-foreground list-disc"
                      >
                        {asText(s)}
                      </li>
                    ))}
                  </ul>
                )}
              </li>
            );
          })}
        </ol>
      )}
      {extra.length > 0 && (
        <dl className="space-y-1">
          {extra.map(([k, val]) => (
            <div key={k} className="flex gap-2 text-xs">
              <dt className="text-muted-foreground font-medium shrink-0">{k}</dt>
              <dd className="text-foreground truncate">{asText(val)}</dd>
            </div>
          ))}
        </dl>
      )}
    </div>
  );
}