import { execSync } from "node:child_process";

export interface GiteaReleaseConfig {
  baseUrl: string;
  token: string;
  owner: string;
  repo: string;
}

export interface GiteaRelease {
  id: number;
  tag_name: string;
  name: string;
  body: string;
  url: string;
  html_url: string;
  draft: boolean;
  prerelease: boolean;
}

export class GiteaClient {
  private config: GiteaReleaseConfig;

  constructor(config: GiteaReleaseConfig) {
    this.config = config;
  }

  async createRelease(params: {
    tag_name: string;
    name: string;
    body: string;
    draft?: boolean;
    prerelease?: boolean;
  }): Promise<GiteaRelease> {
    const url = `${this.config.baseUrl}/api/v1/repos/${this.config.owner}/${this.config.repo}/releases`;
    const response = await fetch(url, {
      method: "POST",
      headers: {
        "Authorization": `token ${this.config.token}`,
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        tag_name: params.tag_name,
        name: params.name,
        body: params.body,
        draft: params.draft ?? false,
        prerelease: params.prerelease ?? false,
      }),
    });

    if (!response.ok) {
      const text = await response.text();
      throw new Error(`Gitea API error: ${response.status} ${text}`);
    }

    return response.json() as Promise<GiteaRelease>;
  }

  async listReleases(): Promise<GiteaRelease[]> {
    const url = `${this.config.baseUrl}/api/v1/repos/${this.config.owner}/${this.config.repo}/releases`;
    const response = await fetch(url, {
      method: "GET",
      headers: {
        "Authorization": `token ${this.config.token}`,
      },
    });

    if (!response.ok) {
      throw new Error(`Gitea API error: ${response.status}`);
    }

    return response.json() as Promise<GiteaRelease[]>;
  }

  async getReleaseByTag(tag: string): Promise<GiteaRelease | null> {
    const url = `${this.config.baseUrl}/api/v1/repos/${this.config.owner}/${this.config.repo}/releases/tags/${tag}`;
    const response = await fetch(url, {
      method: "GET",
      headers: {
        "Authorization": `token ${this.config.token}`,
      },
    });

    if (response.status === 404) {
      return null;
    }

    if (!response.ok) {
      throw new Error(`Gitea API error: ${response.status}`);
    }

    return response.json() as Promise<GiteaRelease>;
  }
}

export function generateReleaseNotes(projectPath: string, fromTag: string | null, toTag: string): string {
  let gitLogCmd: string;
  if (fromTag) {
    gitLogCmd = `git log ${fromTag}..${toTag} --oneline`;
  } else {
    gitLogCmd = `git log ${toTag} --oneline`;
  }

  let logOutput: string;
  try {
    logOutput = execSync(gitLogCmd, { cwd: projectPath, encoding: "utf-8" }).trim();
  } catch {
    return `## What's Changed\n\nNo commits found between ${fromTag || "beginning"} and ${toTag}.\n`;
  }

  if (!logOutput) {
    return `## What's Changed\n\nNo commits found between ${fromTag || "beginning"} and ${toTag}.\n`;
  }

  const lines = logOutput.split("\n").filter(Boolean);

  const featCommits: string[] = [];
  const fixCommits: string[] = [];
  const testCommits: string[] = [];
  const otherCommits: string[] = [];

  for (const line of lines) {
    const subject = line.replace(/^[a-f0-9]+\s+/, "");
    if (/^feat/i.test(subject)) {
      featCommits.push(subject);
    } else if (/^fix/i.test(subject)) {
      fixCommits.push(subject);
    } else if (/^test/i.test(subject)) {
      testCommits.push(subject);
    } else {
      otherCommits.push(subject);
    }
  }

  const sections: string[] = [];

  if (featCommits.length > 0) {
    sections.push("### New Features\n");
    for (const c of featCommits) {
      sections.push(`- ${c}`);
    }
    sections.push("");
  }

  if (fixCommits.length > 0) {
    sections.push("### Bug Fixes\n");
    for (const c of fixCommits) {
      sections.push(`- ${c}`);
    }
    sections.push("");
  }

  if (testCommits.length > 0) {
    sections.push("### Tests\n");
    for (const c of testCommits) {
      sections.push(`- ${c}`);
    }
    sections.push("");
  }

  if (otherCommits.length > 0) {
    sections.push("### Other Changes\n");
    for (const c of otherCommits) {
      sections.push(`- ${c}`);
    }
    sections.push("");
  }

  return `## What's Changed\n\n${sections.join("\n")}`;
}