/* ---- Generate Matrix: duplicate the team's Google Sheets matchup matrix
   template, once per opposing team, pre-filled from this page's own roster
   data plus cleaned army lists (via the vendored 40k-compactor). ----

   Auth: Google Identity Services (GIS) token client — the viewer signs in
   with their own Google account (a real OAuth popup), no backend, no
   client secret. Scopes: drive.file (files this app creates — covers the
   generated matrix copies and everything written to them afterward) plus
   drive.readonly (needed for exactly one thing: reading the pre-existing
   template to copy it — drive.file deliberately can't see a file the app
   didn't create, which is why the first version of this only requesting
   drive.file 404'd on the template with no way to even see it existed —
   Drive's API returns 404, not 403, for a file outside the token's grant,
   so it looks identical to a bad file ID) and spreadsheets. */

import { detectFormat, parseGwAppV11, parseWarOrganV11, parseV11List, generateDiscordText, buildAbbreviationIndex } from "./vendor/40k-compactor/index.js";
import skippableWargear from "./vendor/40k-compactor/skippable_wargear.json";

const GOOGLE_CLIENT_ID = "698705216189-rqbg3f7vlosi3077c3n410a7lpmsn16r.apps.googleusercontent.com";
const TEMPLATE_FILE_ID = "1tSG1BxqLwmMtwFnaHozaLqVsKlmk_QsCXRorIxQBcMo";
const SCOPES = "https://www.googleapis.com/auth/drive.file https://www.googleapis.com/auth/drive.readonly https://www.googleapis.com/auth/spreadsheets";

const DRIVE_API = "https://www.googleapis.com/drive/v3";
const SHEETS_API = "https://sheets.googleapis.com/v4/spreadsheets";

/* ---- List cleaning (vendored 40k-compactor — see vendor/40k-compactor/NOTICE.md) ---- */

// detectFormat() only distinguishes the 11th-edition dialects this parser
// set understands; NR_TOURNAMENT isn't separately parseable from the
// functions this tool exports (no dedicated parser in the vendored code),
// so it falls back to the generic V11 parser same as an unrecognized format.
const PARSERS = {
  GW_APP_V11: parseGwAppV11,
  WAR_ORGAN_V11: parseWarOrganV11,
  V11_GENERIC: parseV11List,
};

// Returns cleaned, sheet-friendly (plain, not Discord-markdown) list text,
// or null if the list couldn't be parsed — callers should fall back to the
// raw text rather than dropping the list entirely.
function cleanListText(rawText) {
  if (!rawText) return null;
  try {
    const lines = String(rawText).split("\n");
    const format = detectFormat(lines);
    const parser = PARSERS[format] || parseV11List;
    const parsed = parser(lines, skippableWargear);
    if (!parsed) return null;
    const abbrIndex = buildAbbreviationIndex(parsed);
    return generateDiscordText(
      parsed,
      true, // plain text — this is going in a spreadsheet cell, not Discord
      true, // use abbreviations
      abbrIndex,
      false, // hide subunits?
      skippableWargear,
      true, // combine identical units?
      { multilineHeader: true, colorMode: "none" }
    );
  } catch (err) {
    console.warn("[matrix] list cleaning failed, falling back to raw text:", err);
    return null;
  }
}

/* ---- Google auth ---- */

let tokenClient = null;
let cachedToken = null; // { access_token, expires_at }

function ensureTokenClient() {
  if (tokenClient) return tokenClient;
  if (!window.google?.accounts?.oauth2) {
    throw new Error("Google Identity Services hasn't loaded yet — try again in a moment.");
  }
  tokenClient = window.google.accounts.oauth2.initTokenClient({
    client_id: GOOGLE_CLIENT_ID,
    scope: SCOPES,
    callback: () => {}, // overridden per-request in getAccessToken()
  });
  return tokenClient;
}

function getAccessToken() {
  if (cachedToken && cachedToken.expires_at > Date.now() + 30_000) {
    return Promise.resolve(cachedToken.access_token);
  }
  return new Promise((resolve, reject) => {
    const client = ensureTokenClient();
    client.callback = resp => {
      if (resp.error) { reject(new Error(`Google sign-in failed: ${resp.error}`)); return; }
      cachedToken = { access_token: resp.access_token, expires_at: Date.now() + (resp.expires_in || 3600) * 1000 };
      resolve(resp.access_token);
    };
    client.requestAccessToken({ prompt: cachedToken ? "" : "consent" });
  });
}

/* ---- Google API helpers ---- */

async function googleFetch(url, token, options = {}) {
  const r = await fetch(url, {
    ...options,
    headers: { Authorization: `Bearer ${token}`, "Content-Type": "application/json", ...options.headers },
  });
  if (!r.ok) {
    const body = await r.text().catch(() => "");
    throw new Error(`Google API ${r.status}: ${body.slice(0, 300)}`);
  }
  return r.json();
}

const copyTemplate = (token, name) =>
  googleFetch(`${DRIVE_API}/files/${TEMPLATE_FILE_ID}/copy?fields=id,webViewLink`, token, {
    method: "POST",
    body: JSON.stringify({ name }),
  });

const getSpreadsheet = (token, fileId) =>
  googleFetch(`${SHEETS_API}/${fileId}?includeGridData=true`, token);

const batchUpdate = (token, fileId, requests) =>
  googleFetch(`${SHEETS_API}/${fileId}:batchUpdate`, token, {
    method: "POST",
    body: JSON.stringify({ requests }),
  });

const batchUpdateValues = (token, fileId, data) =>
  googleFetch(`${SHEETS_API}/${fileId}/values:batchUpdate`, token, {
    method: "POST",
    body: JSON.stringify({ valueInputOption: "USER_ENTERED", data }),
  });

/* ---- Template layout ----
   Deliberately not hardcoding A1 ranges: the implementation searches each
   template tab for its own placeholder text ("Player N - Faction", the
   "Opponent N" row) and works relative to what it finds, so this survives
   the template being tweaked later (rows/columns inserted, etc.) without
   needing a code change. See the plan file for how this was mapped out. */

const PLAYER_ROW_RE = /^Player (\d+) - Faction$/;
const OPPONENT_COL_RE = /^Opponent (\d+)$/;

// The template repeats "Player N - Faction" / "Opponent N" in more than one
// place — a primary input area, plus a "mobile matrix" mirror and a couple
// of reference/lookup sections the sheet's own instructions say to ignore
// ("Ignore the mobile matrix... I have no clue what the purpose is"). CSV
// export can't tell these apart (it only shows computed values), but the
// real API response can: only treat a cell as a genuine placeholder if it's
// literal typed text (userEnteredValue.stringValue), not a formula result
// (e.g. a mirror cell like `=B6`) that merely displays the same text.
function isLiteralText(cell, expected) {
  return cell.userEnteredValue?.stringValue === expected && (cell.formattedValue || "") === expected;
}

// Scans a tab's grid for the template's placeholder cells. Returns null if
// this isn't a matrix template tab (e.g. the instructions tab, or a tab a
// team has already filled in and renamed).
function locateTemplate(sheet) {
  const rows = sheet.data?.[0]?.rowData || [];

  // { col -> [{ row, size }] } — group by column so mirrored/reference
  // occurrences (which land in different columns) don't get mixed together.
  const playerHitsByCol = new Map();
  const opponentHitsByRow = new Map();

  rows.forEach((rowData, rIdx) => {
    (rowData.values || []).forEach((cell, cIdx) => {
      const text = cell.formattedValue || "";
      const pm = text.match(PLAYER_ROW_RE);
      if (pm && isLiteralText(cell, text)) {
        if (!playerHitsByCol.has(cIdx)) playerHitsByCol.set(cIdx, []);
        playerHitsByCol.get(cIdx).push({ row: rIdx, size: Number(pm[1]) });
      }
      const om = text.match(OPPONENT_COL_RE);
      if (om && isLiteralText(cell, text)) {
        if (!opponentHitsByRow.has(rIdx)) opponentHitsByRow.set(rIdx, []);
        opponentHitsByRow.get(rIdx).push({ col: cIdx, size: Number(om[1]) });
      }
    });
  });

  // The real input area is the single column/row with the longest run of
  // *consecutive* placeholder numbers (1, 2, 3, …) — mirrors elsewhere in
  // the sheet may repeat the same set, but this is how we'd tell a genuine
  // partial/edited copy apart from a stray one-off match either way.
  const longestRun = hits => {
    const sorted = [...hits].sort((a, b) => a.size - b.size);
    let best = [], current = [];
    for (const h of sorted) {
      if (current.length && h.size !== current[current.length - 1].size + 1) { current = []; }
      current.push(h);
      if (current.length > best.length) best = current;
    }
    return best;
  };

  let playerCol = null, playerRows = [];
  for (const [col, hits] of playerHitsByCol) {
    const run = longestRun(hits);
    if (run.length > playerRows.length) { playerCol = col; playerRows = run; }
  }

  let opponentRowIdx = null, opponentHits = [];
  for (const [row, hits] of opponentHitsByRow) {
    const run = longestRun(hits);
    if (run.length > opponentHits.length) { opponentRowIdx = row; opponentHits = run; }
  }

  if (!playerRows.length || !opponentHits.length) return null;

  return {
    sheetId: sheet.properties.sheetId,
    title: sheet.properties.title,
    teamSize: Math.max(...opponentHits.map(c => c.size)),
    playerCol,
    playerRows: playerRows.map(p => p.row).sort((a, b) => a - b),
    opponentRow: opponentRowIdx, // "Name and Win Rate" row
    factionRow: opponentRowIdx - 1, // one row up, per the template's own layout
    listRow: opponentRowIdx - 2, // two rows up — "top of each appropriate column"
    opponentCols: opponentHits.sort((a, b) => a.size - b.size).map(c => c.col),
  };
}

// Finds every matrix-template tab in the copied file (there's one per
// supported team size, e.g. 5-man and 8-man) and returns them keyed by size.
function findTemplates(spreadsheet) {
  const templates = new Map(); // teamSize -> layout
  for (const sheet of spreadsheet.sheets) {
    const layout = locateTemplate(sheet);
    if (layout) templates.set(layout.teamSize, layout);
  }
  return templates;
}

function colLetter(idx) {
  let s = "", n = idx;
  do { s = String.fromCharCode(65 + (n % 26)) + s; n = Math.floor(n / 26) - 1; } while (n >= 0);
  return s;
}

const a1 = (sheetTitle, col, row) => `'${sheetTitle.replace(/'/g, "''")}'!${colLetter(col)}${row + 1}`;

/* ---- Row/column value builders ---- */

function playerLabel(member) {
  const name = fullNameOf(member);
  const faction = member.faction?.name || "Unknown";
  return `${name} - ${faction}`;
}

// fullName/fmtWpct live in main.js today; passed in rather than duplicated.
let fullNameOf = () => "";
let fmtWpctOf = () => "—";
export function configureMatrixHelpers({ fullName, fmtWpct }) {
  fullNameOf = fullName;
  fmtWpctOf = fmtWpct;
}

function opponentNameAndWinRate(member, careerRecords) {
  const name = fullNameOf(member);
  const uid = member.userId || member.user?.id;
  const rec = careerRecords.get(uid);
  const wpct = rec ? fmtWpctOf(rec.w, rec.l, rec.t) : "—";
  return `${name} (${wpct})`;
}

/* ---- Orchestration ---- */

// team: one entry from computeTeamRollups(). onProgress(msg) for UI status.
export async function generateMatrix({ event, ourTeam, opposingTeams, careerRecords, bcpToken, onProgress }) {
  onProgress?.("Signing in to Google…");
  const token = await getAccessToken();

  onProgress?.("Copying the matrix template…");
  const copy = await copyTemplate(token, `${event.name || "Event"} — Matrix`);

  onProgress?.("Reading the template…");
  const spreadsheet = await getSpreadsheet(token, copy.id);
  const templates = findTemplates(spreadsheet);
  if (!templates.size) {
    throw new Error("Couldn't find a recognizable template tab (looking for 'Player 1 - Faction' / 'Opponent 1' placeholders) in the copied spreadsheet.");
  }

  const skipped = [];
  let done = 0;

  for (const oppTeam of opposingTeams) {
    onProgress?.(`Building tab ${++done}/${opposingTeams.length}: ${oppTeam.name}…`);

    // Nearest template size at or above this team's actual size (an
    // undersized opponent just leaves trailing columns blank).
    const sizes = [...templates.keys()].sort((a, b) => a - b);
    const size = sizes.find(s => s >= Math.max(oppTeam.members.length, ourTeam.members.length)) || sizes[sizes.length - 1];
    const template = templates.get(size);

    let title;
    try {
      const dup = await batchUpdate(token, copy.id, [{
        duplicateSheet: {
          sourceSheetId: template.sheetId,
          newSheetName: oppTeam.name.slice(0, 100),
        },
      }]);
      title = dup.replies[0].duplicateSheet.properties.title;
    } catch (err) {
      skipped.push({ team: oppTeam.name, reason: `Couldn't duplicate tab: ${err.message}` });
      continue;
    }

    const data = [];
    ourTeam.members.forEach((member, i) => {
      const row = template.playerRows[i];
      if (row == null) return; // template has fewer rows than our roster
      data.push({ range: a1(title, template.playerCol, row), values: [[playerLabel(member)]] });
    });

    let listSkips = 0;
    for (let i = 0; i < oppTeam.members.length; i++) {
      const col = template.opponentCols[i];
      if (col == null) break; // opposing team is larger than this template supports
      const member = oppTeam.members[i];
      data.push({ range: a1(title, col, template.opponentRow), values: [[opponentNameAndWinRate(member, careerRecords)]] });
      data.push({ range: a1(title, col, template.factionRow), values: [[member.faction?.name || "Unknown"]] });

      if (member.listId && bcpToken) {
        try {
          const list = await fetchArmyListText(member.listId, bcpToken);
          const cleaned = cleanListText(list) || list;
          data.push({ range: a1(title, col, template.listRow), values: [[cleaned]] });
        } catch {
          listSkips++;
        }
      } else if (member.listId) {
        listSkips++;
      }
    }
    if (listSkips) skipped.push({ team: oppTeam.name, reason: `${listSkips} list(s) not fetched — add a BCP auth token above to include them.` });

    try {
      await batchUpdateValues(token, copy.id, data);
    } catch (err) {
      skipped.push({ team: oppTeam.name, reason: `Tab created but couldn't write data: ${err.message}` });
    }
  }

  return { url: copy.webViewLink || `https://docs.google.com/spreadsheets/d/${copy.id}/edit`, skipped };
}

// Same BCP endpoint/shape as fetchArmyList() in main.js (kept local rather
// than imported to keep this module's dependency surface self-contained).
async function fetchArmyListText(listId, token) {
  const r = await fetch(`https://newprod-api.bestcoastpairings.com/v1/armylists/${listId}`, {
    headers: { "client-id": "web-app", "env": "bcp", "accept": "application/json", authorization: `Bearer ${token}` },
  });
  if (!r.ok) throw new Error(`armylists/${r.status}`);
  const list = await r.json();
  return list.armyListText || "";
}