import { Image, View } from "@react-pdf/renderer";
import type { ReactNode } from "react";
import { pinned, type ColSpec } from "../../engine/columns";
import { CLOSING_ID, TOTALS_ID } from "../../engine/ids";
import { AvailableWidthProvider } from "../../blocks/AvailableWidth";
import { BottomSpacer } from "../../blocks/BottomSpacer";
import { FirstPageHeader } from "../../blocks/FirstPageHeader";
import { fitSize, FitText } from "../../blocks/FitText";
import { IdText } from "../../blocks/IdText";
import { TableRows } from "../../blocks/ItemsTable";
import { Row } from "../../blocks/Row";
import { SafeTxt } from "../../blocks/SafeTxt";
import { Slot } from "../../blocks/slots";
import { TableGuard } from "../../blocks/TableGuard";
import { Txt } from "../../blocks/Txt";
import { AccentRule } from "../../decor/AccentRule";
import type { TypeToken } from "../../fonts/roles";
import { META_ID, SUPPLIER_ID, TITLE_ID } from "../classic/ids";
import type { PlacedLogo, TemplateProps } from "../contract";
import { includesName } from "../logoName";
import { CANCELLED_INK, CANCELLED_SENTENCE } from "../neutral/plan";
import { LABEL_GAP, NOTES_FLOW_GAP, PARTY_GUTTER, payableLines, planMarble, REVERSE_GAP, signatureOptions, stepOf, taxLabel, type MarblePlan } from "./plan";
import { RULE, ZEBRA, type MarbleVariant } from "./tokens";

/** Room that must remain under the notes' label and first line, so the next lines are not squeezed into the page foot. */
const NOTES_HOLD = 70;

/** Layout-tree ids of the blocks that are Marble's own (the harness ids are in classic/ids.ts). */
export const IDS_ID = "marble-ids";
export const PAYABLE_ID = "marble-payable";
export const BILL_ID = "marble-bill";

interface Ctx {
  model: TemplateProps["model"];
  plan: MarblePlan;
  v: MarbleVariant;
  logo: PlacedLogo | null;
}

function Spacer({ h }: { h: number }) {
  return h > 0 ? <View style={{ height: h }} /> : null;
}

function Rule({ ctx }: { ctx: Ctx }) {
  return <AccentRule width={ctx.plan.W} thickness={ctx.v.rule} color={RULE} />;
}

/**
 * One right-aligned line of tracked text. textkit adds the tracking after the last glyph too, so the box is
 * widened by one step and pulled back with a negative margin: the ink then ends on the edge.
 */
function RightText({ role, color, width, children }: { role: TypeToken; color: string; width: number; children: string }) {
  const step = stepOf(role);
  const fit = fitSize(role, children, width + step);
  if (!fit.fits) {
    return (
      <IdText role={role} color={color} width={width} align="right" fill>
        {children}
      </IdText>
    );
  }
  const sized = { ...role, size: fit.size };
  const s = stepOf(sized);
  return (
    <Txt role={sized} color={color} width={width + s} align="right" style={{ marginRight: -s }}>
      {children}
    </Txt>
  );
}

// --- header -----------------------------------------------------------------------------------------------------

/** The vendor name (Lustria caps) or its logo; the design leaves this corner empty. */
function Brand({ ctx }: { ctx: Ctx }) {
  const { model, plan, v, logo } = ctx;
  const h = plan.head;
  const hd = v.head;
  return (
    <View id={SUPPLIER_ID} style={{ ...pinned(h.leftW), marginLeft: v.inset.left } as never}>
      {logo ? (
        <View style={{ ...pinned(h.leftW), height: Math.max(hd.logoH, h.logoTop + logo.h) } as never}>
          <Image src={logo.dataUri} style={{ ...pinned(logo.w), height: logo.h, marginTop: h.logoTop, objectFit: "contain" } as never} />
        </View>
      ) : null}
      {h.showName ? (
        <View style={{ ...pinned(h.leftW), marginTop: logo ? hd.nameGap : hd.nameTop } as never}>
          <AvailableWidthProvider width={h.leftW}>
            <SafeTxt role={v.roles.brand} color={v.ink}>
              {model.supplier.name}
            </SafeTxt>
          </AvailableWidthProvider>
        </View>
      ) : null}
    </View>
  );
}

function Stack({ ctx }: { ctx: Ctx }) {
  const { model, plan, v } = ctx;
  const h = plan.head;
  const r = v.roles;
  return (
    <View style={{ ...pinned(h.stackW), paddingTop: v.head.titleTop } as never}>
      <FitText id={TITLE_ID} role={{ ...r.title, size: h.titleSize }} color={v.ink} width={h.stackW + stepOf({ ...r.title, size: h.titleSize })} align="right" style={{ marginRight: -stepOf({ ...r.title, size: h.titleSize }) }}>
        {model.docTitle}
      </FitText>
      <View id={META_ID} style={{ ...pinned(h.stackW), marginTop: v.head.titleGap } as never}>
        <AvailableWidthProvider width={h.stackW}>
          {h.lines.map((l, i) => (
            <RightText key={i} role={r.meta} color={l.kind === "cancelled" ? CANCELLED_INK : v.ink} width={h.stackW}>
              {l.text}
            </RightText>
          ))}
        </AvailableWidthProvider>
      </View>
    </View>
  );
}

function HeaderRow({ ctx }: { ctx: Ctx }) {
  const { plan } = ctx;
  return (
    <Row widths={[{ fill: true }, { fixed: plan.head.stackW }]} width={plan.W} style={{ minHeight: plan.head.h }}>
      <Brand ctx={ctx} />
      <Stack ctx={ctx} />
    </Row>
  );
}

// --- parties ----------------------------------------------------------------------------------------------------

function ClientBlock({ ctx, width }: { ctx: Ctx; width: number }) {
  const { model, v } = ctx;
  const r = v.roles;
  const c = model.client;
  return (
    <View id={BILL_ID} style={pinned(width) as never}>
      <AvailableWidthProvider width={width}>
        <Txt role={r.heading} color={v.ink} width={width} style={{ marginBottom: v.parties.headingGap }}>
          Bill to:
        </Txt>
        <SafeTxt role={r.body} color={v.ink}>
          {c.name}
        </SafeTxt>
        {c.addressLines.map((line, i) => (
          <SafeTxt key={i} role={r.body} color={v.ink}>
            {line}
          </SafeTxt>
        ))}
        <Slot.Gstin model={model} party="client" role={r.body} color={v.ink} />
        <Slot.PlaceOfSupply model={model} role={r.body} color={v.ink} />
        {c.poNumber ? <SafeTxt role={r.body} color={v.ink}>{`PO: ${c.poNumber}`}</SafeTxt> : null}
      </AvailableWidthProvider>
    </View>
  );
}

function PayableBlock({ ctx, width }: { ctx: Ctx; width: number }) {
  const { model, v } = ctx;
  const r = v.roles;
  return (
    <View id={PAYABLE_ID} style={pinned(width) as never}>
      <AvailableWidthProvider width={width}>
        <Txt role={r.heading} color={v.ink} width={width} style={{ marginBottom: v.parties.headingGap }}>
          Payable to:
        </Txt>
        {payableLines(model).map((line, i) => (
          <SafeTxt key={i} role={r.body} color={v.ink}>
            {line}
          </SafeTxt>
        ))}
      </AvailableWidthProvider>
    </View>
  );
}

function IdsBlock({ ctx, width }: { ctx: Ctx; width: number }) {
  const { model, v } = ctx;
  const r = v.roles;
  const s = model.supplier;
  return (
    <View id={IDS_ID} style={pinned(width) as never}>
      <AvailableWidthProvider width={width}>
        <Txt role={r.heading} color={v.ink} width={width} style={{ marginBottom: v.parties.headingGap }}>
          Supplier:
        </Txt>
        <Slot.Gstin model={model} party="supplier" role={r.body} color={v.ink} />
        {s.pan ? (
          <IdText role={r.body} color={v.ink}>
            {`PAN: ${s.pan}`}
          </IdText>
        ) : null}
      </AvailableWidthProvider>
    </View>
  );
}

function Parties({ ctx }: { ctx: Ctx }) {
  const { plan, v } = ctx;
  const cols = plan.info.cols;
  const text = cols.map((w) => Math.max(40, w - PARTY_GUTTER));
  const blocks: ReactNode[] = [<ClientBlock key="a" ctx={ctx} width={text[0]} />];
  let k = 1;
  if (plan.info.hasBank) blocks.push(<PayableBlock key="b" ctx={ctx} width={text[k++]} />);
  if (plan.info.hasIds) blocks.push(<IdsBlock key="c" ctx={ctx} width={text[k++]} />);
  const specs: ColSpec[] = cols.map((w, i) => (i === cols.length - 1 ? { fill: true } : { fixed: w }));
  return (
    <View style={{ ...pinned(plan.W), paddingLeft: v.inset.left } as never}>
      <Row widths={specs} width={plan.W - v.inset.left}>
        {blocks}
      </Row>
    </View>
  );
}

// --- totals -----------------------------------------------------------------------------------------------------

function StackRow({ ctx, label, amount }: { ctx: Ctx; label: string; amount: string }) {
  const { plan, v } = ctx;
  const t = plan.tail;
  const r = v.roles;
  const labelW = t.boxW - t.valueW;
  return (
    <Row widths={[{ fixed: labelW }, { fixed: t.valueW }]} width={t.boxW} style={v.totals.rowGap ? { marginBottom: v.totals.rowGap } : undefined}>
      <Txt role={r.totalLabel} color={v.ink} width={labelW}>
        {label}
      </Txt>
      <RightText role={r.totalValue} color={v.ink} width={t.valueW}>
        {amount}
      </RightText>
    </Row>
  );
}

function TotalsBox({ ctx }: { ctx: Ctx }) {
  const { model, plan, v } = ctx;
  const t = plan.tail;
  return (
    <View style={pinned(t.boxW) as never}>
      <AvailableWidthProvider width={t.boxW}>
        {t.stack.map((row, i) => (
          <StackRow key={i} ctx={ctx} label={row.label} amount={row.amount} />
        ))}
        <Slot.TaxRows model={model} role={v.roles.totalLabel} color={v.ink} amountWidth={t.valueW} format={taxLabel} renderRow={(row) => <StackRow ctx={ctx} label={row.label} amount={row.amount} />} />
        <View style={{ marginTop: v.totals.dueGap, ...pinned(t.boxW) } as never}>
          <RightText role={{ ...v.roles.due, size: t.dueSize }} color={v.ink} width={t.boxW}>
            {t.dueText}
          </RightText>
        </View>
      </AvailableWidthProvider>
    </View>
  );
}

function Tail({ ctx }: { ctx: Ctx }) {
  const { model, plan, v } = ctx;
  const t = plan.tail;
  const r = v.roles;
  const o = v.totals;
  return (
    <View id={TOTALS_ID} wrap={false} style={pinned(plan.W) as never}>
      <Spacer h={plan.gaps.tail} />
      <Row widths={[{ fill: true }, { fixed: t.boxW }]} gap={o.leftGap} width={plan.W - o.rightInset}>
        <View style={{ ...pinned(t.leftW), marginLeft: v.inset.left } as never}>
          <AvailableWidthProvider width={t.leftW}>
            <Slot.AmountInWords model={model} role={r.small} labelRole={r.smallLabel} color={v.ink} />
            {t.reverseH > 0 ? <Slot.ReverseCharge model={model} role={r.small} color={v.ink} style={{ marginTop: t.wordsH > 0 ? REVERSE_GAP : 0 }} /> : null}
          </AvailableWidthProvider>
        </View>
        <TotalsBox ctx={ctx} />
      </Row>
    </View>
  );
}

// --- closing ----------------------------------------------------------------------------------------------------

/** Notes: a label held with the first line, every line unbreakable (a cut Text would leave a zero-line node). */
function Notes({ ctx, width }: { ctx: Ctx; width: number }) {
  const { plan, v } = ctx;
  const r = v.roles;
  const lines = plan.closing.notes;
  if (lines.length === 0) return null;
  return (
    <View style={pinned(width) as never}>
      <AvailableWidthProvider width={width}>
        <View wrap={false}>
          <Txt role={r.smallLabel} color={v.ink} width={width} style={{ marginBottom: LABEL_GAP }}>
            Notes:
          </Txt>
          <SafeTxt role={r.small} color={v.ink}>
            {lines[0]}
          </SafeTxt>
        </View>
        {lines.slice(1).map((line, i) => (
          <SafeTxt key={i} role={r.small} color={v.ink} wrap={false}>
            {line}
          </SafeTxt>
        ))}
      </AvailableWidthProvider>
    </View>
  );
}

function Closing({ ctx }: { ctx: Ctx }) {
  const { model, plan, v } = ctx;
  const cl = v.closing;
  const c = plan.closing;
  const opts = signatureOptions(v);
  return (
    <>
      <BottomSpacer closingH={plan.closingH} />
      <View id={CLOSING_ID} wrap={false} style={pinned(plan.W) as never}>
        <AvailableWidthProvider width={plan.W}>
          <Spacer h={plan.gaps.close} />
          <Row widths={[{ fill: true }, { fixed: cl.signW }]} gap={cl.gap} width={plan.W - v.totals.rightInset}>
            <View style={{ ...pinned(c.notesW), marginLeft: v.inset.left } as never}>{c.notesBeside ? <Notes ctx={ctx} width={c.notesW} /> : null}</View>
            <Slot.Signatory model={model} width={cl.signW} {...opts} />
          </Row>
          {model.cancelled ? (
            <Txt role={v.roles.small} color={CANCELLED_INK} width={plan.W} style={{ marginTop: 10, marginLeft: v.inset.left }}>
              {CANCELLED_SENTENCE}
            </Txt>
          ) : null}
        </AvailableWidthProvider>
      </View>
    </>
  );
}

// --- the layout -------------------------------------------------------------------------------------------------

export function MarbleBody({ model, frame, logo, prefs, variant: v }: TemplateProps & { variant: MarbleVariant }) {
  const plan = planMarble(model, frame, v, logo, includesName({ model, prefs }));
  const ctx: Ctx = { model, plan, v, logo };
  const r = v.roles;
  const t = v.table;
  const notesFlow: ReactNode =
    plan.closing.notesBeside || plan.closing.notes.length === 0 ? null : (
      <>
        {/* A block that starts with less than a line of room left is cut into zero-height lines: it starts on the next page instead. */}
        <TableGuard {...{ minPresenceAhead: NOTES_FLOW_GAP + NOTES_HOLD }} />
        <View style={{ marginTop: NOTES_FLOW_GAP, marginLeft: v.inset.left }}>
          <Notes ctx={ctx} width={plan.W - v.inset.left - v.totals.rightInset} />
        </View>
      </>
    );
  return (
    <>
      <FirstPageHeader pad={frame.pad}>
        <HeaderRow ctx={ctx} />
        <Spacer h={plan.gaps.headRule} />
        <Rule ctx={ctx} />
        <Spacer h={plan.gaps.infoTop} />
        <Parties ctx={ctx} />
        <Spacer h={plan.gaps.infoBottom} />
        <Rule ctx={ctx} />
      </FirstPageHeader>

      <Spacer h={plan.gaps.band} />

      <TableGuard {...{ minPresenceAhead: plan.guardH }} />
      <View style={pinned(plan.W) as never}>
        <TableRows
          columns={plan.columns}
          gap={0}
          width={plan.W}
          header={plan.headerCells}
          rows={plan.rows}
          roles={{ head: r.tableHead, body: r.tableBody }}
          align={plan.align}
          padX={0}
          padLeft={plan.padLeft}
          padRight={plan.padRight}
          padY={plan.padY}
          headPadY={0}
          border={0}
          headBorder={0}
          headColor={v.ink}
          rowStyle={(i) => (i % 2 === 0 ? { backgroundColor: ZEBRA } : {})}
          headCellStyle={(i) => (i === 0 ? { marginLeft: -(t.descInset - t.headDescInset) } : undefined)}
          headerTail={<Spacer h={t.headGap} />}
          headerTailH={t.headGap}
          tailH={plan.tailH}
          tail={<Tail ctx={ctx} />}
        />
      </View>
      {notesFlow}
      <Closing ctx={ctx} />
    </>
  );
}