// models/linear-entities.ts
import { z } from "zod";

// Core entity schemas
export const LinearIssueSchema = z.object({
  id: z.string(),
  identifier: z.string(),
  title: z.string(),
  description: z.string().nullable(),
  priority: z.number(),
  estimate: z.number().nullable(),
  stateId: z.string(),
  stateName: z.string(),
  teamId: z.string(),
  teamKey: z.string(),
  assigneeId: z.string().nullable(),
  projectId: z.string().nullable(),
  cycleId: z.string().nullable(),
  createdAt: z.string(),
  updatedAt: z.string(),
  completedAt: z.string().nullable(),
  canceledAt: z.string().nullable(),
});

export type LinearIssue = z.infer<typeof LinearIssueSchema>;

export const LinearProjectSchema = z.object({
  id: z.string(),
  name: z.string(),
  description: z.string().nullable(),
  state: z.string(),
  progress: z.number(),
  targetDate: z.string().nullable(),
  createdAt: z.string(),
  updatedAt: z.string(),
});

export type LinearProject = z.infer<typeof LinearProjectSchema>;

// sync/full-sync.ts
import { LinearClient, Issue } from "@linear/sdk";
import { db } from "../lib/database";
import { LinearIssueSchema } from "../models/linear-entities";

interface SyncStats {
  total: number;
  created: number;
  updated: number;
  deleted: number;
  errors: number;
}

export async function fullSync(client: LinearClient): Promise<SyncStats> {
  const stats: SyncStats = { total: 0, created: 0, updated: 0, deleted: 0, errors: 0 };

  console.log("Starting full sync...");

  // Fetch all issues with pagination
  const remoteIssues = new Map<string, LinearIssue>();
  let hasMore = true;
  let cursor: string | undefined;

  while (hasMore) {
    const issues = await client.issues({
      first: 100,
      after: cursor,
      includeArchived: false,
    });

    for (const issue of issues.nodes) {
      const state = await issue.state;
      const team = await issue.team;

      const mapped: LinearIssue = {
        id: issue.id,
        identifier: issue.identifier,
        title: issue.title,
        description: issue.description,
        priority: issue.priority,
        estimate: issue.estimate,
        stateId: state?.id ?? "",
        stateName: state?.name ?? "Unknown",
        teamId: team?.id ?? "",
        teamKey: team?.key ?? "",
        assigneeId: issue.assigneeId,
        projectId: issue.projectId,
        cycleId: issue.cycleId,
        createdAt: issue.createdAt.toISOString(),
        updatedAt: issue.updatedAt.toISOString(),
        completedAt: issue.completedAt?.toISOString() ?? null,
        canceledAt: issue.canceledAt?.toISOString() ?? null,
      };

      remoteIssues.set(issue.id, mapped);
    }

    hasMore = issues.pageInfo.hasNextPage;
    cursor = issues.pageInfo.endCursor;

    console.log(`  Fetched ${remoteIssues.size} issues...`);
  }

  stats.total = remoteIssues.size;

  // Get local issues
  const localIssues = await db.select().from(issuesTable);
  const localIssueMap = new Map(localIssues.map(i => [i.id, i]));

  // Process changes
  await db.transaction(async (tx) => {
    // Upsert remote issues
    for (const [id, issue] of remoteIssues) {
      const existing = localIssueMap.get(id);

      if (!existing) {
        await tx.insert(issuesTable).values(issue);
        stats.created++;
      } else if (existing.updatedAt !== issue.updatedAt) {
        await tx.update(issuesTable).set(issue).where(eq(issuesTable.id, id));
        stats.updated++;
      }
    }

    // Mark deleted issues
    for (const [id, local] of localIssueMap) {
      if (!remoteIssues.has(id) && !local.deletedAt) {
        await tx.update(issuesTable)
          .set({ deletedAt: new Date().toISOString() })
          .where(eq(issuesTable.id, id));
        stats.deleted++;
      }
    }
  });

  console.log("Full sync complete:", stats);
  return stats;
}

// sync/incremental-sync.ts
import { db } from "../lib/database";

interface WebhookEvent {
  action: "create" | "update" | "remove";
  type: string;
  data: Record<string, unknown>;
  createdAt: string;
}

export async function processWebhookSync(event: WebhookEvent): Promise<void> {
  const { action, type, data } = event;

  if (type !== "Issue") return;

  const issueData = data as any;

  switch (action) {
    case "create":
      await db.insert(issuesTable).values({
        id: issueData.id,
        identifier: issueData.identifier,
        title: issueData.title,
        // ... map all fields
        syncedAt: new Date().toISOString(),
      });
      break;

    case "update":
      await db.update(issuesTable)
        .set({
          title: issueData.title,
          // ... update changed fields
          syncedAt: new Date().toISOString(),
        })
        .where(eq(issuesTable.id, issueData.id));
      break;

    case "remove":
      await db.update(issuesTable)
        .set({ deletedAt: new Date().toISOString() })
        .where(eq(issuesTable.id, issueData.id));
      break;
  }
}

// backup/export.ts
import { LinearClient } from "@linear/sdk";
import { createWriteStream } from "fs";
import { pipeline } from "stream/promises";

interface BackupOptions {
  includeComments?: boolean;
  includeAttachments?: boolean;
  format?: "json" | "csv";
}

export async function createBackup(
  client: LinearClient,
  outputPath: string,
  options: BackupOptions = {}
): Promise<void> {
  const { includeComments = true, format = "json" } = options;

  const backup = {
    exportedAt: new Date().toISOString(),
    version: "1.0",
    data: {
      teams: [] as any[],
      projects: [] as any[],
      cycles: [] as any[],
      issues: [] as any[],
      comments: [] as any[],
    },
  };

  console.log("Creating backup...");

  // Export teams
  const teams = await client.teams();
  backup.data.teams = await Promise.all(
    teams.nodes.map(async (team) => ({
      id: team.id,
      name: team.name,
      key: team.key,
      description: team.description,
    }))
  );
  console.log(`  Exported ${backup.data.teams.length} teams`);

  // Export projects
  const projects = await client.projects();
  backup.data.projects = projects.nodes.map(p => ({
    id: p.id,
    name: p.name,
    description: p.description,
    state: p.state,
    targetDate: p.targetDate,
  }));
  console.log(`  Exported ${backup.data.projects.length} projects`);

  // Export issues with pagination
  let cursor: string | undefined;
  let hasMore = true;

  while (hasMore) {
    const issues = await client.issues({
      first: 100,
      after: cursor,
      includeArchived: true,
    });

    for (const issue of issues.nodes) {
      const issueData: any = {
        id: issue.id,
        identifier: issue.identifier,
        title: issue.title,
        description: issue.description,
        priority: issue.priority,
        createdAt: issue.createdAt,
        updatedAt: issue.updatedAt,
      };

      if (includeComments) {
        const comments = await issue.comments();
        issueData.comments = comments.nodes.map(c => ({
          id: c.id,
          body: c.body,
          createdAt: c.createdAt,
        }));
      }

      backup.data.issues.push(issueData);
    }

    hasMore = issues.pageInfo.hasNextPage;
    cursor = issues.pageInfo.endCursor;
  }
  console.log(`  Exported ${backup.data.issues.length} issues`);

  // Write to file
  const output = format === "json"
    ? JSON.stringify(backup, null, 2)
    : convertToCSV(backup);

  await fs.writeFile(outputPath, output);
  console.log(`Backup saved to ${outputPath}`);
}

// sync/consistency-check.ts
import { LinearClient } from "@linear/sdk";
import { db } from "../lib/database";

interface ConsistencyReport {
  timestamp: string;
  issues: {
    total: number;
    missing: string[];
    stale: string[];
    orphaned: string[];
  };
}

export async function checkConsistency(client: LinearClient): Promise<ConsistencyReport> {
  const report: ConsistencyReport = {
    timestamp: new Date().toISOString(),
    issues: {
      total: 0,
      missing: [],
      stale: [],
      orphaned: [],
    },
  };

  // Get sample of remote issues
  const remoteIssues = await client.issues({ first: 100 });
  report.issues.total = remoteIssues.nodes.length;

  // Check each remote issue exists locally
  for (const remote of remoteIssues.nodes) {
    const local = await db.query.issues.findFirst({
      where: eq(issues.id, remote.id),
    });

    if (!local) {
      report.issues.missing.push(remote.identifier);
    } else if (new Date(local.updatedAt) < remote.updatedAt) {
      report.issues.stale.push(remote.identifier);
    }
  }

  // Check for orphaned local issues
  const localIssues = await db.select({ id: issues.id, identifier: issues.identifier })
    .from(issues)
    .where(isNull(issues.deletedAt))
    .limit(100);

  for (const local of localIssues) {
    try {
      await client.issue(local.id);
    } catch {
      report.issues.orphaned.push(local.identifier);
    }
  }

  return report;
}

// Run periodically
export async function scheduleConsistencyChecks(): Promise<void> {
  cron.schedule("0 0 * * *", async () => {
    const client = new LinearClient({ apiKey: process.env.LINEAR_API_KEY! });
    const report = await checkConsistency(client);

    if (report.issues.missing.length > 0 || report.issues.stale.length > 10) {
      await alertOncall("Data consistency issues detected", report);
      await fullSync(client); // Trigger resync
    }
  });
}

// sync/conflict-resolution.ts
interface ConflictStrategy {
  strategy: "remote-wins" | "local-wins" | "merge" | "manual";
  mergeFields?: string[];
}

export async function resolveConflict(
  local: LinearIssue,
  remote: LinearIssue,
  config: ConflictStrategy
): Promise<LinearIssue> {
  switch (config.strategy) {
    case "remote-wins":
      return remote;

    case "local-wins":
      return local;

    case "merge":
      // Merge specific fields
      const merged = { ...remote };
      for (const field of config.mergeFields ?? []) {
        if (local[field as keyof LinearIssue] !== undefined) {
          (merged as any)[field] = local[field as keyof LinearIssue];
        }
      }
      return merged;

    case "manual":
      throw new ConflictError(local, remote);

    default:
      return remote;
  }
}