import * as Tool from "./tool"
import { CallToolResultSchema, type CallToolResult } from "@modelcontextprotocol/sdk/types.js"
import { Cause, Effect, Schema } from "effect"
import {
  CodeMode,
  Tool as SandboxTool,
  toolError,
  type ExecuteResult,
  type JsonSchema,
  type ToolDefinition,
} from "@opencode-ai/codemode"
import { MCP } from "@/mcp"
import { McpCatalog } from "@/mcp/catalog"
import { Agent } from "@/agent/agent"
import { Session } from "@/session/session"
import { Permission } from "@/permission"
import { Plugin } from "@/plugin"

export const CODE_MODE_TOOL = "execute"

const DESCRIPTION = [
  "Execute a JavaScript/TypeScript program that orchestrates the connected MCP tools inside a confined runtime.",
  "The full usage guide and the catalog of available tools follow below.",
].join("\n")

export const Parameters = Schema.Struct({
  code: Schema.String.annotate({
    description: [
      "JavaScript source to execute.",
      "Inside CodeMode, `tools` contains only the MCP/CodeMode tools listed in this execute tool's description; top-level opencode tools like bash, read, or lsp are not available unless listed there.",
      "Call available tools using the exact signatures shown in this execute tool's description, compose the results, and `return` the final value.",
    ].join(" "),
  }),
})

type CallEntry = { tool: string; status: "running" | "completed" | "error"; input?: Record<string, unknown> }

type Metadata = {
  toolCalls: CallEntry[]
  error?: boolean
}

type Attachment = NonNullable<Tool.ExecuteResult["attachments"]>[number]

type CatalogEntry = {
  path: string
  key: string
  server: string
  local: string
  tool: MCP.McpTool
}

const toJsonSchema = (schema: unknown): JsonSchema => schema as JsonSchema

function groupByServer(mcpTools: Record<string, MCP.McpTool>, servers: readonly string[]): Map<string, CatalogEntry[]> {
  const byLongest = [...servers].sort((a, b) => b.length - a.length)
  const groups = new Map<string, CatalogEntry[]>()
  for (const key of Object.keys(mcpTools).sort((a, b) => a.localeCompare(b))) {
    const server =
      byLongest.find((name) => key.startsWith(name + "_")) ?? (key.includes("_") ? key.slice(0, key.indexOf("_")) : key)
    const local = server && key.startsWith(server + "_") ? key.slice(server.length + 1) : key
    const entry: CatalogEntry = {
      path: `${server}.${local}`,
      key,
      server,
      local,
      tool: mcpTools[key]!,
    }
    groups.set(server, [...(groups.get(server) ?? []), entry])
  }
  return groups
}

export function describeCatalog(mcpTools: Record<string, MCP.McpTool>, servers: readonly string[]): string {
  return CodeMode.make({
    tools: toolTree(
      [...groupByServer(mcpTools, servers).values()].flat(),
      () => () => Effect.fail(toolError("Tool preview is not executable.")),
    ),
  }).instructions()
}

const lastSegment = (uri: string) => {
  const trimmed = uri.split(/[?#]/, 1)[0]!.replace(/\/+$/, "")
  const segment = trimmed.slice(trimmed.lastIndexOf("/") + 1)
  return segment.length > 0 ? segment : undefined
}

const dataUrl = (mime: string, base64: string) => `data:${mime};base64,${base64}`

function projectMcpResult(result: CallToolResult, collect: (attachment: Attachment) => void): unknown {
  const text: string[] = []
  let files = 0
  let images = 0
  const push = (attachment: Attachment) => {
    files += 1
    if (attachment.mime.startsWith("image/")) images += 1
    collect(attachment)
  }
  for (const block of result.content) {
    switch (block.type) {
      case "text":
        text.push(block.text)
        break
      case "image":
      case "audio":
        push({ type: "file", mime: block.mimeType, url: dataUrl(block.mimeType, block.data) })
        break
      case "resource": {
        if ("text" in block.resource) {
          text.push(block.resource.text)
          break
        }
        const mime = block.resource.mimeType ?? "application/octet-stream"
        push({ type: "file", mime, url: dataUrl(mime, block.resource.blob), filename: lastSegment(block.resource.uri) })
        break
      }
      case "resource_link":
        push({
          type: "file",
          mime: block.mimeType ?? "application/octet-stream",
          url: block.uri,
          filename: block.name,
        })
        break
    }
  }

  if (result.structuredContent !== undefined && result.structuredContent !== null) return result.structuredContent
  if (text.length > 0) return text.join("\n")
  if (files > 0) {
    const noun = files === images ? "image" : "file"
    return `[${files} ${noun}${files === 1 ? "" : "s"} attached to the result]`
  }
  return null
}

type Run = (input: unknown) => Effect.Effect<unknown, unknown>

function toolTree(catalog: readonly CatalogEntry[], run: (entry: CatalogEntry) => Run) {
  const tree: Record<string, Record<string, ToolDefinition>> = {}
  for (const entry of catalog) {
    const namespace = (tree[entry.server] ??= {})
    namespace[entry.local] = SandboxTool.make({
      description: entry.tool.def.description ?? "",
      input: toJsonSchema(entry.tool.def.inputSchema),
      output: entry.tool.def.outputSchema ? toJsonSchema(entry.tool.def.outputSchema) : undefined,
      run: run(entry),
    })
  }
  return tree
}

const invokeChildTool = Effect.fn("CodeMode.invokeChildTool")(function* (input: {
  plugin: Plugin.Interface
  entry: CatalogEntry
  args: Record<string, unknown>
  callID: string
  ctx: Tool.Context
}) {
  yield* input.plugin.trigger(
    "tool.execute.before",
    { tool: input.entry.key, sessionID: input.ctx.sessionID, callID: input.callID },
    { args: input.args },
  )
  const result: CallToolResult = yield* Effect.gen(function* () {
    yield* input.ctx.ask({ permission: input.entry.key, metadata: {}, patterns: ["*"], always: ["*"] })
    // Deliberately mirrors McpCatalog.convertTool's transport call so the MCP service stays free of tool-loop concerns.
    return yield* Effect.promise(async () => {
      const raw = await input.entry.tool.client.callTool(
        { name: input.entry.tool.def.name, arguments: input.args },
        CallToolResultSchema,
        {
          resetTimeoutOnProgress: true,
          signal: input.ctx.abort,
          timeout: input.entry.tool.timeout,
          // The MCP SDK only sends a progress token when this hook is present, enabling timeout resets.
          onprogress: () => {},
        },
      )
      if (raw.isError)
        throw new Error(
          raw.content
            .flatMap((item) => (item.type === "text" ? [item.text] : []))
            .filter((text) => text.trim())
            .join("\n\n") || "MCP tool returned an error",
        )
      return raw
    })
  }).pipe(
    Effect.withSpan("Tool.execute", {
      attributes: {
        "tool.name": input.entry.key,
        "tool.call_id": input.callID,
        "session.id": input.ctx.sessionID,
        "message.id": input.ctx.messageID,
      },
    }),
  )
  yield* input.plugin.trigger(
    "tool.execute.after",
    { tool: input.entry.key, sessionID: input.ctx.sessionID, callID: input.callID, args: input.args },
    result,
  )
  return result
})

export const CodeModeTool = Tool.define(
  CODE_MODE_TOOL,
  Effect.gen(function* () {
    const mcp = yield* MCP.Service
    const agents = yield* Agent.Service
    const sessions = yield* Session.Service
    const plugin = yield* Plugin.Service

    const init: Tool.DefWithoutID<typeof Parameters, Metadata> = {
      description: DESCRIPTION,
      parameters: Parameters,
      execute: Effect.fn("CodeMode.execute")(function* (params, ctx) {
        if (ctx.abort.aborted) {
          return {
            title: CODE_MODE_TOOL,
            metadata: { toolCalls: [], error: true },
            output: "Execution cancelled.",
          } satisfies Tool.ExecuteResult<Metadata>
        }
        const agent = yield* agents.get(ctx.agent)
        const session = yield* sessions.get(ctx.sessionID).pipe(Effect.orDie)
        const ruleset = Permission.merge(agent.permission, session.permission ?? [])
        const mcpTools = Permission.visibleTools(yield* mcp.tools(), ruleset)
        const servers = Object.keys(yield* mcp.clients()).map(McpCatalog.sanitize)
        const catalog = [...groupByServer(mcpTools, servers).values()].flat()

        const calls: CallEntry[] = []
        const attachments: Attachment[] = []
        const collect = (attachment: Attachment) => void attachments.push(attachment)
        const publish = () =>
          ctx.metadata({ title: CODE_MODE_TOOL, metadata: { toolCalls: calls.map((c) => ({ ...c })) } })

        let childCalls = 0
        const callTool = (entry: CatalogEntry) => (input: unknown) =>
          Effect.gen(function* () {
            childCalls += 1
            const result = yield* invokeChildTool({
              plugin,
              entry,
              args: (input ?? {}) as Record<string, unknown>,
              callID: `${ctx.callID ?? entry.key}/${childCalls}`,
              ctx,
            })
            return projectMcpResult(result, collect)
          }).pipe(
            Effect.catchCause((cause) => {
              if (Cause.hasInterruptsOnly(cause)) return Effect.interrupt
              const error = Cause.squash(cause)
              return Effect.fail(toolError(error instanceof Error ? error.message : String(error), error))
            }),
          )

        const runtime = CodeMode.make({
          tools: toolTree(catalog, callTool),
          onToolCallStart: ({ index, name, input }) =>
            Effect.suspend(() => {
              const shown = (() => {
                if (input === null || input === undefined) return
                if (typeof input === "object" && !Array.isArray(input)) {
                  const value = input as Record<string, unknown>
                  return Object.keys(value).length > 0 ? value : undefined
                }
                return { input }
              })()
              calls[index] = { tool: name, status: "running", ...(shown ? { input: shown } : {}) }
              return publish()
            }),
          onToolCallEnd: ({ index, outcome }) =>
            Effect.suspend(() => {
              const current = calls[index]
              if (current) calls[index] = { ...current, status: outcome === "success" ? "completed" : "error" }
              return publish()
            }),
        })

        const abort = Effect.callback<void>((resume) => {
          if (ctx.abort.aborted) return resume(Effect.void)
          const handler = () => resume(Effect.void)
          ctx.abort.addEventListener("abort", handler, { once: true })
          return Effect.sync(() => ctx.abort.removeEventListener("abort", handler))
        })
        const cancelled = (): ExecuteResult => ({
          ok: false,
          error: { kind: "ExecutionFailure", message: "Execution cancelled." },
          toolCalls: calls.map((call) => ({ name: call.tool })),
        })

        const result = yield* Effect.raceFirst(
          runtime.execute(params.code),
          abort.pipe(Effect.map(cancelled)),
        )
        const logs = result.logs ?? []
        const attached = attachments.length > 0 ? { attachments } : {}
        const hints = result.ok
          ? []
          : (result.error.suggestions ?? []).filter((hint) => !result.error.message.includes(hint))
        const metadata: Metadata = result.ok ? { toolCalls: calls } : { toolCalls: calls, error: true }
        let output: string
        if (result.ok) {
          if (typeof result.value === "string") output = result.value
          else if (result.value === undefined) output = "undefined"
          else {
            try {
              output = JSON.stringify(result.value, null, 2) ?? String(result.value)
            } catch {
              output = String(result.value)
            }
          }
        } else {
          output = [result.error.message, ...hints].join("\n")
        }
        if (logs.length > 0)
          output = output.length > 0 ? `${output}\n\nLogs:\n${logs.join("\n")}` : `Logs:\n${logs.join("\n")}`

        return {
          title: CODE_MODE_TOOL,
          metadata,
          output,
          ...attached,
        } satisfies Tool.ExecuteResult<Metadata>
      }),
    }
    return init
  }),
)