import { pullInput, requirePull } from "~/server/pull-access";
import { limitHeavy, limitWrite } from "~/server/limits";
import { createServerFn } from "@tanstack/react-start";
import { z } from "zod";
import { requireViewer, viewerMiddleware } from "./middleware";
import { all, first } from "~/server/db";
import { loadRepo, repoPermission, requireRepoAccess } from "~/server/repos";
import { branchSha, listRefs } from "~/server/git/refs";
import { withStore } from "~/server/git/store";
import { compareCommits } from "~/server/git/history";
import { checkMergeability, mergeGate } from "~/server/pulls";
import { findForkHead, mergePullRequest, openPull } from "~/server/pull-create";
import { updatePull as updatePullRequest } from "~/server/pull-automation";
import { pullDiff } from "~/server/pull-files";
import { parseSuggestion } from "~/server/suggestions";
import { pullAutomation } from "~/server/merge-queue";
import { listLinkedIssues } from "~/server/pull-links";
import { listCommitStatuses, combinedState } from "~/server/statuses";
import { accountOrGhost, accountsById } from "~/server/people";
import { renderMarkdown } from "~/server/markdown";
import { reactionSummaries } from "~/server/reactions";
import { notFoundError } from "~/server/errors";
import { markdownBody, repoRef, title } from "~/lib/validation";
import type { RepoRow } from "~/lib/types";

export const createPull = createServerFn({ method: "POST" })
  .middleware([viewerMiddleware])
  .validator(
    repoRef.extend({
      base: z.string().min(1),
      head: z.string().min(1),
      title,
      body: markdownBody,
      draft: z.boolean().default(false),
    }),
  )
  .handler(async ({ data, context }) => {
    const viewer = requireViewer(context.viewer);
    await limitWrite(viewer);
    const { repo } = await requireRepoAccess(data.owner, data.repo, viewer, "read");
    const separator = data.head.indexOf(":");
    const headRepo = separator === -1 ? repo : await loadRepo(data.head.slice(0, separator), "");
    let resolvedHeadRepo: RepoRow | null = headRepo;
    const headRef = separator === -1 ? data.head : data.head.slice(separator + 1);
    if (separator !== -1) {
      resolvedHeadRepo = await findForkHead(repo, data.head.slice(0, separator));
    }
    if (!resolvedHeadRepo || (await repoPermission(resolvedHeadRepo, viewer)) === "none")
      throw notFoundError("Head repository not found");
    const number = await openPull({
      repo,
      headRepo: resolvedHeadRepo,
      headRef,
      base: data.base,
      title: data.title,
      body: data.body,
      draft: data.draft,
      viewer,
    });
    return { number };
  });

export const getPull = createServerFn({ method: "GET" })
  .middleware([viewerMiddleware])
  .validator(pullInput)
  .handler(async ({ data, context }) => {
    const { repo, permission, pull, headRepo } = await requirePull(
      data.owner,
      data.repo,
      data.number,
      context.viewer,
      "read",
    );
    const [statuses, gate, reviewRows, requested, automation, linkedIssues] = await Promise.all([
      listCommitStatuses(repo.id, pull.head_sha),
      mergeGate(pull, permission),
      all<{ id: string; author_id: string; state: string; commit_sha: string; dismiss_reason: string | null }>(
        `SELECT id, author_id, state, commit_sha, dismiss_reason FROM reviews
         WHERE issue_id = ? AND state != 'commented' ORDER BY created_at`,
        pull.issue_id,
      ),
      all<{ user_id: string; code_owner: number }>(
        "SELECT user_id, code_owner FROM review_requests WHERE issue_id = ?",
        pull.issue_id,
      ),
      pullAutomation(pull),
      listLinkedIssues(pull),
    ]);
    const latestReviews = new Map<string, (typeof reviewRows)[number]>();
    for (const review of reviewRows) latestReviews.set(review.author_id, review);
    const people = await accountsById([
      pull.merged_by,
      automation.autoMerge?.enabledBy ?? null,
      ...latestReviews.keys(),
      ...requested.map((row) => row.user_id),
    ]);
    const comparison = await withStore(repo.artifacts_name, (baseStore) =>
      withStore(headRepo.artifacts_name, (headStore) =>
        compareCommits(baseStore, pull.base_sha, headStore, pull.head_sha),
      ),
    );
    const headBranchExists = branchSha(await listRefs(headRepo), pull.head_ref) !== null;
    return {
      pull: {
        number: pull.number,
        headRef: pull.head_ref,
        headSha: pull.head_sha,
        headLabel: headRepo.id === repo.id ? pull.head_ref : `${headRepo.owner_name}:${pull.head_ref}`,
        headRepo: { owner: headRepo.owner_name, name: headRepo.name },
        baseRef: pull.base_ref,
        draft: pull.draft === 1,
        mergeable: pull.mergeable,
        merged: pull.merged_at !== null,
        mergedAt: pull.merged_at,
        mergedBy: pull.merged_by ? accountOrGhost(people, pull.merged_by) : null,
        mergeCommitSha: pull.merge_commit_sha,
        commitsCount: comparison.commits.length,
        behindBy: comparison.behindBy,
        headBranchExists,
      },
      checks: statuses.map((status) => ({
        context: status.context,
        state: status.state,
        description: status.description,
        targetUrl: status.target_url,
      })),
      checksState: combinedState(statuses),
      gate,
      reviews: [...latestReviews.entries()].map(([userId, review]) => ({
        id: review.id,
        reviewer: accountOrGhost(people, userId),
        state: review.state,
        stale: review.commit_sha !== pull.head_sha,
        dismissReason: review.dismiss_reason,
      })),
      requestedReviewers: requested.map((row) => ({
        ...accountOrGhost(people, row.user_id),
        codeOwner: row.code_owner === 1,
      })),
      autoMerge: automation.autoMerge && {
        method: automation.autoMerge.method,
        enabledBy: accountOrGhost(people, automation.autoMerge.enabledBy),
      },
      queue: automation.queue,
      linkedIssues,
      canUpdateBranch: comparison.behindBy > 0 && pull.state === "open",
      canMerge: permission === "write" || permission === "admin",
      canPushHead: (await repoPermission(headRepo, context.viewer)) !== "read",
    };
  });

export const getPullCommits = createServerFn({ method: "GET" })
  .middleware([viewerMiddleware])
  .validator(pullInput)
  .handler(async ({ data, context }) => {
    const { repo, pull, headRepo } = await requirePull(data.owner, data.repo, data.number, context.viewer, "read");
    const base = pull.merged_at && pull.merge_base_sha ? pull.merge_base_sha : pull.base_sha;
    return withStore(repo.artifacts_name, (baseStore) =>
      withStore(
        headRepo.artifacts_name,
        async (headStore) => (await compareCommits(baseStore, base, headStore, pull.head_sha)).commits,
      ),
    );
  });

export const getPullFiles = createServerFn({ method: "GET" })
  .middleware([viewerMiddleware])
  .validator(pullInput.extend({ commit: z.string().length(40).optional(), since: z.string().length(40).optional() }))
  .handler(async ({ data, context }) => {
    await limitHeavy(context.viewer);
    const { repo, pull, headRepo } = await requirePull(data.owner, data.repo, data.number, context.viewer, "read");
    const { diff, commits, range } = await pullDiff(pull, repo, headRepo, { commit: data.commit, since: data.since });
    const lastReview = context.viewer
      ? await first<{ commit_sha: string }>(
          "SELECT commit_sha FROM reviews WHERE issue_id = ? AND author_id = ? ORDER BY created_at DESC LIMIT 1",
          pull.issue_id,
          context.viewer.id,
        )
      : null;
    const comments = await all<{
      id: string;
      author_id: string;
      path: string;
      line: number;
      side: "LEFT" | "RIGHT";
      start_line: number | null;
      start_side: "LEFT" | "RIGHT" | null;
      body: string;
      commit_sha: string;
      suggestion_applied_sha: string | null;
      in_reply_to: string | null;
      resolved: number;
      created_at: number;
    }>("SELECT * FROM review_comments WHERE issue_id = ? ORDER BY created_at", pull.issue_id);
    const [people, reactions] = await Promise.all([
      accountsById(comments.map((comment) => comment.author_id)),
      reactionSummaries(
        "review_comment",
        comments.map((comment) => comment.id),
        context.viewer?.id ?? null,
      ),
    ]);
    return {
      diff,
      commits,
      range,
      lastReviewSha: lastReview?.commit_sha ?? null,
      headSha: pull.head_sha,
      comments: comments.map((comment) => ({
        id: comment.id,
        author: accountOrGhost(people, comment.author_id),
        path: comment.path,
        line: comment.line,
        side: comment.side,
        startLine: comment.start_line,
        startSide: comment.start_side,
        hasSuggestion: parseSuggestion(comment.body) !== null,
        suggestionApplied: comment.suggestion_applied_sha !== null,
        html: renderMarkdown(comment.body, {
          owner: repo.owner_name,
          repo: repo.name,
          ref: pull.head_sha,
          basePath: "",
        }),
        outdated: comment.commit_sha !== pull.head_sha,
        inReplyTo: comment.in_reply_to,
        resolved: comment.resolved === 1,
        createdAt: comment.created_at,
        reactions: reactions.get(comment.id) ?? [],
      })),
    };
  });

export const mergePull = createServerFn({ method: "POST" })
  .middleware([viewerMiddleware])
  .validator(
    pullInput.extend({
      method: z.enum(["merge", "squash", "rebase"]),
      message: z.string().max(10_000),
      deleteBranch: z.boolean().default(false),
      expectedHead: z.string().length(40),
      timezone: z
        .string()
        .regex(/^[+-]\d{4}$/)
        .optional(),
    }),
  )
  .handler(async ({ data, context }) => {
    const viewer = requireViewer(context.viewer);
    await limitWrite(viewer);
    const { repo, permission, pull, headRepo } = await requirePull(data.owner, data.repo, data.number, viewer, "write");
    const sha = await mergePullRequest({
      repo,
      permission,
      pull,
      headRepo,
      viewer,
      method: data.method,
      message: data.message,
      deleteBranch: data.deleteBranch,
      expectedHead: data.expectedHead,
      timezone: data.timezone,
    });
    return { sha };
  });

export const updatePull = createServerFn({ method: "POST" })
  .middleware([viewerMiddleware])
  .validator(pullInput.extend({ base: z.string().optional(), draft: z.boolean().optional() }))
  .handler(async ({ data, context }) => {
    const viewer = requireViewer(context.viewer);
    const access = await requirePull(data.owner, data.repo, data.number, viewer, "read");
    await updatePullRequest(access, viewer, data);
    return { ok: true };
  });

export const recheckMergeability = createServerFn({ method: "POST" })
  .middleware([viewerMiddleware])
  .validator(pullInput)
  .handler(async ({ data, context }) => {
    await limitHeavy(requireViewer(context.viewer));
    const { pull } = await requirePull(data.owner, data.repo, data.number, context.viewer, "read");
    return { mergeable: await checkMergeability(pull) };
  });