/**
 * 「改动」tab 的扩展侧 handler：实时从 Gitea 读整个 PR 的改动文件清单，并按需取
 * 单个文件改动前后的原文，交给 webview 内联渲染（主从式 diff）。
 *
 * 数据全程实时拉取，只把「已查看」确认态落到 `.spx/pr-review-confirmed.json`
 * （按文件变更指纹失效：作者推新提交后，仅真改动过的文件掉勾，没动的保留）。diff
 * 左右两侧用 merge_base → head 的原文，与 Gitea 网页 diff 口径一致；getRawFile 对
 * 404 兜底空串，故新增/删除/改名天然成立。
 */

import type { KanbanWebviewPanel } from '../KanbanPanel'
import { createPatch } from 'diff'
import { workspace } from 'vscode'
import { getToken } from '../../auth/secrets'
import { listClaudeProfiles } from '../../cc/profiles'
import { spawnClaude } from '../../cc/spawnClaude'
import { detectRepo } from '../../git/remote'
import { getPullRequest, getRawFile, listPullRequestFiles } from '../../gitea/api'
import { readStateJsonComment } from '../../gitea/stateJson'
import { readFileSummaries, readSummarySession, writeFileSummary, writeSummarySession } from '../../sessions/prFileSummaryStore'
import { readConfirmedSigs, writeConfirmedSigs } from '../../sessions/prReviewStore'
import { parsePrDiffMode, type PrDiffMode } from '../../cc/prDiffMode'
import { makeNonce } from '../KanbanPanel'

/**
 * 解析当前工作区的 Gitea 仓库与 token。三者任一缺失返回 undefined，
 * 调用方据此走空态/错误分支。
 */
async function resolveRepoContext(panel: KanbanWebviewPanel): Promise<
  { host: string, owner: string, repo: string, token: string } | undefined
> {
  const workspaceRoot = workspace.workspaceFolders?.[0]?.uri.fsPath
  if (!workspaceRoot)
    return undefined
  const remote = await detectRepo(workspaceRoot)
  if (!remote)
    return undefined
  const token = await getToken(panel.context, remote.host)
  if (!token)
    return undefined
  return { host: remote.host, owner: remote.owner, repo: remote.repo, token }
}

/** 从工单的 state JSON 取 PR 号。无则返回 undefined（前端按空态处理，不算错误）。 */
async function resolvePrNumber(
  ctx: { host: string, owner: string, repo: string, token: string },
  issueNumber: number,
): Promise<number | undefined> {
  const stateObj = await readStateJsonComment({
    host: ctx.host,
    owner: ctx.owner,
    repo: ctx.repo,
    token: ctx.token,
    issueNumber,
  })
  const pr = typeof stateObj?.pr === 'string' && stateObj.pr.length > 0 ? stateObj.pr : undefined
  return pr ? Number(pr) : undefined
}

/** 由文件扩展名推断高亮语言 id（highlight.js/lowlight 口径）；未知则回退扩展名本身。 */
function langFromPath(path: string): string {
  const ext = path.split('.').pop()?.toLowerCase() ?? ''
  const map: Record<string, string> = {
    ts: 'typescript',
    tsx: 'typescript',
    js: 'javascript',
    jsx: 'javascript',
    mjs: 'javascript',
    cjs: 'javascript',
    json: 'json',
    py: 'python',
    go: 'go',
    rs: 'rust',
    java: 'java',
    kt: 'kotlin',
    kts: 'kotlin',
    rb: 'ruby',
    php: 'php',
    c: 'c',
    h: 'c',
    cpp: 'cpp',
    cc: 'cpp',
    hpp: 'cpp',
    cs: 'csharp',
    swift: 'swift',
    md: 'markdown',
    markdown: 'markdown',
    yml: 'yaml',
    yaml: 'yaml',
    toml: 'toml',
    ini: 'ini',
    sh: 'bash',
    bash: 'bash',
    zsh: 'bash',
    sql: 'sql',
    css: 'css',
    scss: 'scss',
    less: 'less',
    html: 'xml',
    htm: 'xml',
    xml: 'xml',
    vue: 'xml',
    svelte: 'xml',
  }
  return map[ext] ?? ext
}

/** 文件「变更指纹」：内容一改，status/additions/deletions 几乎必变其一；用于判定已查看是否仍有效。 */
function fileSig(f: { status: string, additions: number, deletions: number }): string {
  return `${f.status}|${f.additions}|${f.deletions}`
}

/**
 * 拉取工单对应 PR 的全部改动文件清单 + 已查看集合 + 已生成说明，推给 webview。
 * 无 PR/缺上下文回空（前端按空态处理）；真出错才带 error。
 *
 * 已查看按「变更指纹」判定：取每个文件当前的 status|additions|deletions，与落盘记录的
 * 指纹比对，仅相符的文件仍算已查看——作者推新提交后只有真改动过的文件掉勾。比对后顺手把
 * 已失配/已消失的条目从盘上剪掉。
 */
export async function handleGetPrFiles(panel: KanbanWebviewPanel, issueNumber: number): Promise<void> {
  try {
    const ctx = await resolveRepoContext(panel)
    if (!ctx) {
      panel.postMessage({ type: 'pr-files/show', issueNumber, files: [], confirmed: [], summaries: {} })
      return
    }

    const index = await resolvePrNumber(ctx, issueNumber)
    if (index === undefined) {
      panel.postMessage({ type: 'pr-files/show', issueNumber, files: [], confirmed: [], summaries: {} })
      return
    }

    const files = await listPullRequestFiles({
      host: ctx.host,
      owner: ctx.owner,
      repo: ctx.repo,
      token: ctx.token,
      index,
    })

    const workspaceRoot = workspace.workspaceFolders?.[0]?.uri.fsPath
    let confirmed: string[] = []
    let summaries: Record<string, string> = {}
    if (workspaceRoot) {
      const [stored, sums] = await Promise.all([
        readConfirmedSigs(workspaceRoot, issueNumber),
        readFileSummaries(workspaceRoot, issueNumber),
      ])
      summaries = sums
      // 当前每文件的变更指纹；仅指纹相符的已查看条目仍有效。
      const cur = new Map(files.map(f => [f.path, fileSig(f)]))
      confirmed = Object.keys(stored).filter(p => cur.get(p) === stored[p])
      // 有失配/消失才写盘，剪掉陈旧条目，避免无谓磁盘写入。
      if (confirmed.length !== Object.keys(stored).length) {
        const pruned: Record<string, string> = {}
        for (const p of confirmed)
          pruned[p] = stored[p]
        await writeConfirmedSigs(workspaceRoot, issueNumber, pruned)
      }
    }

    panel.postMessage({ type: 'pr-files/show', issueNumber, files, confirmed, summaries })
  }
  catch (err) {
    panel.postMessage({
      type: 'pr-files/show',
      issueNumber,
      files: [],
      confirmed: [],
      summaries: {},
      error: err instanceof Error ? err.message : String(err),
    })
  }
}

/**
 * 取单个文件改动前后的原文：左 = previousPath@mergeBase（无改名则 path），
 * 右 = path@head。两侧原文 + 语言推断回给 webview，由 git-diff-view 内联渲染。
 */
export async function handleGetPrFileDiff(
  panel: KanbanWebviewPanel,
  args: { issueNumber: number, path: string, previousPath?: string },
): Promise<void> {
  try {
    const ctx = await resolveRepoContext(panel)
    if (!ctx) {
      panel.postMessage({ type: 'pr-file-diff/show', issueNumber: args.issueNumber, path: args.path, oldContent: '', newContent: '' })
      return
    }
    const index = await resolvePrNumber(ctx, args.issueNumber)
    if (index === undefined) {
      panel.postMessage({ type: 'pr-file-diff/show', issueNumber: args.issueNumber, path: args.path, oldContent: '', newContent: '' })
      return
    }

    const pr = await getPullRequest({ host: ctx.host, owner: ctx.owner, repo: ctx.repo, token: ctx.token, index })
    const mergeBase = pr.mergeBase || pr.baseSha
    const oldPath = args.previousPath ?? args.path
    const [oldContent, newContent] = await Promise.all([
      getRawFile({ host: ctx.host, owner: ctx.owner, repo: ctx.repo, token: ctx.token, filepath: oldPath, ref: mergeBase }),
      getRawFile({ host: ctx.host, owner: ctx.owner, repo: ctx.repo, token: ctx.token, filepath: args.path, ref: pr.headSha }),
    ])
    panel.postMessage({
      type: 'pr-file-diff/show',
      issueNumber: args.issueNumber,
      path: args.path,
      oldContent,
      newContent,
      oldLang: langFromPath(oldPath),
      newLang: langFromPath(args.path),
    })
  }
  catch (err) {
    panel.postMessage({
      type: 'pr-file-diff/show',
      issueNumber: args.issueNumber,
      path: args.path,
      oldContent: '',
      newContent: '',
      error: err instanceof Error ? err.message : String(err),
    })
  }
}

/**
 * 持久化某 PR 的「已查看文件 → 变更指纹」映射到 `.spx/pr-review-confirmed.json`。
 * 拿不到工作区根则静默跳过；写盘失败兜底打日志、不抛——确认态丢失不该中断 UI。
 */
export async function handleSetPrReviewConfirmed(
  _panel: KanbanWebviewPanel,
  args: { issueNumber: number, confirmed: Record<string, string> },
): Promise<void> {
  try {
    const workspaceRoot = workspace.workspaceFolders?.[0]?.uri.fsPath
    if (!workspaceRoot)
      return
    await writeConfirmedSigs(workspaceRoot, args.issueNumber, args.confirmed)
  }
  catch (err) {
    console.warn('handleSetPrReviewConfirmed 写盘失败', err)
  }
}

/**
 * 生成说明的 prompt：只要一句「这个文件改了什么」，给审查者扫一眼用。
 * 首条垫入 PR 描述当背景并立下问法；续会话只发新文件，复用已有 PR 理解、省 token。
 */
function buildSummaryPrompt(prNumber: number, prBody: string, filePath: string, patch: string, isFirst: boolean): string {
  if (isFirst) {
    const body = prBody.trim()
    const prContext = body
      ? `我在逐个审查 PR #${prNumber} 的改动，本 PR 的说明如下：\n${body}\n\n`
      : `我在逐个审查 PR #${prNumber} 的改动。`
    return `${prContext}针对下面这个文件的改动，用一句简短中文说明改了什么 / 改了哪些东西。只输出这一句话，不要分点、不要 ①②、不要 markdown 加粗，不要解释为什么改、不要写不做的后果，不要复述整段代码或罗列函数/结构。\n\n文件: ${filePath}\n\n\`\`\`diff\n${patch}\n\`\`\``
  }
  return `下一个文件，同样只用一句简短中文说明改了什么，不要分点、不要 ①②、不要解释为什么或后果。\n文件: ${filePath}\n\`\`\`diff\n${patch}\n\`\`\``
}

/**
 * 用 deepseek 给单个文件生成「一句话说明改了什么」的改动说明。增量复用同一会话：首个文件开新会话并把
 * sessionId 记到 `.spx/pr-file-summaries.json`，后续文件 `--resume` 接上去，省去每次重新理解
 * PR 的开销。说明也落盘，重载后仍显示。
 *
 * diff 取 merge_base → head 两版原文用 jsdiff 拼 unified diff 喂给模型（比塞两份全文省 token）。
 * spawnClaude 走 spawn 数组参数、不经 shell，故 patch 里的引号/换行无需转义。
 */
export async function handleGeneratePrFileSummary(
  panel: KanbanWebviewPanel,
  args: { issueNumber: number, path: string, previousPath?: string },
): Promise<void> {
  const { issueNumber, path: filePath } = args
  try {
    const workspaceRoot = workspace.workspaceFolders?.[0]?.uri.fsPath
    const ctx = await resolveRepoContext(panel)
    if (!ctx || !workspaceRoot) {
      panel.postMessage({ type: 'pr-file-summary/show', issueNumber, path: filePath, error: '当前工作区没有 Gitea 仓库或未配置 token' })
      return
    }

    // deepseek profile 与「一键提交」同一来源；缺失则提示用户创建并清掉前端 loading。
    const profiles = await listClaudeProfiles()
    const deepseek = profiles.find(p => p.name === 'deepseek-v4-pro')
    if (!deepseek) {
      panel.postMessage({
        type: 'toast/show',
        id: makeNonce(),
        level: 'error',
        message: '未找到 deepseek profile（deepseek-v4-pro / deepseek），请在 Claude profiles 目录下创建对应 .json',
        dismissOnTimer: 8000,
      })
      panel.postMessage({ type: 'pr-file-summary/show', issueNumber, path: filePath, error: '未找到 deepseek profile' })
      return
    }

    const index = await resolvePrNumber(ctx, issueNumber)
    if (index === undefined) {
      panel.postMessage({ type: 'pr-file-summary/show', issueNumber, path: filePath, error: '该工单还没有 PR' })
      return
    }

    const pr = await getPullRequest({ host: ctx.host, owner: ctx.owner, repo: ctx.repo, token: ctx.token, index })
    const mergeBase = pr.mergeBase || pr.baseSha
    const oldPath = args.previousPath ?? filePath
    const [oldContent, newContent] = await Promise.all([
      getRawFile({ host: ctx.host, owner: ctx.owner, repo: ctx.repo, token: ctx.token, filepath: oldPath, ref: mergeBase }),
      getRawFile({ host: ctx.host, owner: ctx.owner, repo: ctx.repo, token: ctx.token, filepath: filePath, ref: pr.headSha }),
    ])
    const patch = createPatch(filePath, oldContent, newContent, '', '')

    const prevSession = await readSummarySession(workspaceRoot, issueNumber)
    let result
    try {
      result = await spawnClaude({
        prompt: buildSummaryPrompt(index, pr.body, filePath, patch, !prevSession),
        cwd: workspaceRoot,
        profilePath: deepseek.path,
        resumeSessionId: prevSession,
        timeoutMs: 120_000,
      })
    }
    catch (err) {
      // resume 失败（会话过期/被清理）→ 丢弃旧 id，按首次重开一个会话再试一次。
      if (!prevSession)
        throw err
      await writeSummarySession(workspaceRoot, issueNumber, undefined)
      result = await spawnClaude({
        prompt: buildSummaryPrompt(index, pr.body, filePath, patch, true),
        cwd: workspaceRoot,
        profilePath: deepseek.path,
        timeoutMs: 120_000,
      })
    }

    // 模型偶发仍加 **①**/**②** → 轻量去标记；一句话约束主要靠 prompt
    const summary = result.resultText
      .trim()
      .replace(/\s+/g, ' ')
      .replace(/(?:\*{0,2}[①②]\*{0,2}\s*)+/g, '')
      .trim()
    await writeFileSummary(workspaceRoot, issueNumber, filePath, summary)
    await writeSummarySession(workspaceRoot, issueNumber, result.sessionId)
    panel.postMessage({ type: 'pr-file-summary/show', issueNumber, path: filePath, summary })
  }
  catch (err) {
    panel.postMessage({
      type: 'pr-file-summary/show',
      issueNumber,
      path: filePath,
      error: err instanceof Error ? err.message : String(err),
    })
  }
}

const PR_DIFF_MODE_KEY = 'prDiffMode'

/** 读 workspace 级 diff 模式（缺省 unified），回推 webview。 */
export function handleGetPrDiffMode(panel: KanbanWebviewPanel): void {
  const stored = panel.context.workspaceState.get<unknown>(PR_DIFF_MODE_KEY)
  const mode = parsePrDiffMode(stored)
  panel.postMessage({ type: 'pr-diff-mode/show', mode })
}

/** 写 workspace 级 diff 模式；非法值按 unified 落盘。 */
export async function handleSetPrDiffMode(
  panel: KanbanWebviewPanel,
  mode: unknown,
): Promise<void> {
  const next: PrDiffMode = parsePrDiffMode(mode)
  await panel.context.workspaceState.update(PR_DIFF_MODE_KEY, next)
}